Coronary MRA

Hall D                                   Thursday 13:30-15:30                                                                                                                                           

                  935.       Coronary Magnetic Resonance Angiography Using Non Spatially Selective Navigator Excitations at 3T

Harsh K. Agarwal1, Khaled Z. Abd-Elmoniem1, Michael Schär1, 2, Sebastian Kelle1, Matthias Stuber1, Jerry L. Prince1

1Johns Hopkins University, Baltimore, Maryland, USA; 2Phillips Medical System, Best, Netherlands

B0 inhomogeneity, reduced T2* and off-resonant fat excitation may adversely affect the performance of 2D selective navigator technology, particularly at higher magnetic field strength. Furthermore, localization of a 2D selective navigator is user dependent and time consuming. A navigator technique which uses non-spatially selective excitation in conjunction with local surface coil navigator signal reception is proposed to circumvent the aforementioned issues.

                  936.       Contrast-Enhanced Whole-Heart Coronary MR Angiography at 3.0 T: Comparison to Steady-State Free
                                Precession Imaging at 1.5 T

Xin Liu1, Xiaoming Bi, Nondas Leloudas, Renate Jerecic, James C. Carr, Debiao Li

1Northwestern University, Chicago, Illinois, USA

To compare contrast-enhanced whole-heart coronary MRA at 3.0T and steady-state free precession imaging at 1.5 T, 11 healthy volunteers underwent both 3.0 T and 1.5 T coronary MRA using 3D FLASH with slow infusion of MultiHance and 3D TrueFISP, respectively. SNR, CNR, image quality, and coverage of coronary segments were analyzed and compared statistically. Contrast-enhanced whole-heart coronary MRA at 3.0 T demonstrated higher CNR, less acquisition time, and better depiction of coronary segments compared to non-contrast SSFP coronary MRA at 1.5 T.

                  937.       Time-Resolved Contrast-Enhanced Coronary MRA with HYPR PR: A Feasibility Study

Lan Ge1, Xiaoming Bi1, Peng Lai1, Hua Peng1, Andrew Larson1, Debiao Li1

1Northwestern University, Chicago, Illinois, USA

During contrast-enhanced coronary MRA, the blood signal changes during the contrast injection time will result in image artifacts, blurring and relatively low SNR, when the k-space segments from different cardiac cycles are combined to reconstruct the final image as ¡ time-averaged¡±. Thus, it is important to acquire data during maximal blood signal enhancement from firstmpass, therefore requiring relatively high temporal resolution. This work demonstrated the feasibility of HYPR PR for time-resolved, contrast-enhanced coronary MRA with an increased temporal resolution. HYPR processed coronary artery images around the time of peak blood signal enhancement significantly improved CNR and suppressed artifacts compared to conventional composite images.

                  938.       "One-Stop Shop" MRI of Coronary Heart Disease at 3T: Technical Feasibility

Lan Ge1, Aya Kino1, Xiaoming Bi2, Xin Liu1, Natasha Berg1, Renate Jerecic2, James Carr1, Debiao Li1

1Northwestern University, Chicago, Illinois, USA; 2Siemens Medical Solutions, Chicago, Illinois, USA

Cardiac MRI is a promising tool to detect and evaluate myocardial ischemic disease. Various MRI techniques have been developed, including functional cine scan, first pass myocardial perfusion (FPMP), coronary MRA, and delayed enhancement imaging. Nevertheless, these techniques have not been applied in the same imaging session for a comprehensive examination. The study demonstrated the feasibility of a comprehensive protocol ¡ One Stop Shop¡± for cardiac MRI at 3T. The ¡ one stop shop¡± cardiac MRI was successfully acquired in 4 volunteers with an average time of 43 minutes.

                  939.       Whole-Heart Magnetic Resonance Coronary Angiography (WH MRCA) with Visual Feedback for Use
                                in a Clinical Setting
 [Not Available]

Shigehide Kuhara1, Tomohisa Okada2, Shotaro Kanao2, Ayako Ninomiya1, Saori Satou1, Toshikazu Kamae2, Kimio Goto2, Kaori Togashi2

1Toshiba Medical Systems, Otawara-shi, Japan; 2Kyoto University Hospital, Kyoto, Japan

We have developed a visual feedback (VFB) system that displays the breathing level to the patient, thus permitting the patient to adjust his or her breathing level. The present study was undertaken to investigate the usefulness of the VFB system in WH MRCA studies, aiming to perform abdominal band-free examinations for clinical use.Using the VFB system, WH MRCA can be performed with less difficulty and without prolonging the scan time, and, in particular, multi-breath-hold WH MRCA with VFB provides the best image quality in the shortest practical time.

                  940.       Contrast Enhanced Coronary Artery Imaging in a Breath-Hold at 3 Tesla Using 3D Segmented EPI:
                                A Feasibility Study

Himanshu V. Bhat1, Sven Zuehlsdorff2, Xiaoming Bi2, Renate Jerecic2, Debiao Li1

1Northwestern University, Chicago, Illinois, USA; 2Siemens Medical Solutions, Chicago, Illinois, USA

Contrast enhanced coronary artery magnetic resonance angiography (CMRA) at 3T has recently shown very promising results. Imaging time on the order of five minutes was reported for a whole heart acquisition. Further reduction of the imaging time is required to make CMRA more robust and clinically applicable. Segmented EPI is a method which can be exploited to provide a significant speed gain for CMRA and has previously been reported at 1.5T. In this work the feasibility of 3D segmented EPI for breath-hold high resolution CMRA at 3T has been shown. Segmented EPI is a promising technique for contrast enhanced coronary artery imaging at 3T.

                  941.       Whole-Heart Coronary Angiography at Isotropic Spatial Resolution:  High SENSE Acceleration at 3T
                                Utilizing a  32 Element Cardiac Receive Coil

Axel Bornstedt1, Vinzenz Hombach1, Marc Kouwenhoven, Volker Rasche1

1University of Ulm, Ulm, Germany

Possible improvement of image acquisition time for whole-heart coronary angiography at isotropic spatial resolution by application of a 32-element cardiac coil is presented. It is shown that parallel imaging factors of up to 7.5 can be applied without severe image degradation.

                  942.       NMR Signals from Hyperpolarized Xe-129 Dissolved in Atherosclerotic Plaques

Zhaohui Han1, Nicholas N. Kuzma1

1University of Rochester, Rochester, USA

We report the first confirmed NMR signals from hyperpolarized Xenon-129 (HP Xe-129) dissolved in atherosclerotic plaques of mouse aortas. HP Xe-129 has a broad range of properties that make it a biosensor of choice to characterize biological systems. These properties include high sensitivity to molecular environments, high solubility in biological tissues, and several orders of magnitude increase in NMR signal intensity by optical pumping. Exploring the use of xenon for atherosclerosis diagnostics, we have performed ex-vivo NMR on excised mouse aortas. We have detected characteristic signals from HP Xe-129 dissolved in the atherosclerotic plaques of the apolipoprotein E-deficient mouse.

                  943.       Free-Breathing Steady-State Free Precession 3D Coronary MRA: Comparison of Diaphragm and
                                Cardiac Fat Navigator Gating Techniques

Thanh D. Nguyen1, Pascal Spincemaille1, Matthew D. Cham1, Jonathan W. Weinsaft1, Martin R. Prince1, Yi Wang1

1Weill Medical College of Cornell University, New York, New York, USA

The objective of this study was to compare the performance of diaphragm navigator (DNAV) and cardiac fat navigator (FNAV) in free-breathing SSFP 3D CMRA. Imaging was performed in 16 volunteers at 1.5T using the PAWS real-time gating algorithm. Interpretable CMRA was obtained in all subjects with FNAV gating (0% failure rate) and only 14 subjects with DNAV gating (12% failure rate). Compared to DNAV gating, FNAV gating was found to provide more effective motion suppression, significantly better image quality (P<0.01), and a 30% improvement in average navigator efficiency (P=0.002).

                  944.       A Comparison Study of Four Navigator Gating Techniques in Free-Breathing Steady-State Free Precession
                                3D Coronary MR Angiography

Thanh D. Nguyen1, Pascal Spincemaille1, Matthew D. Cham1, Jonathan W. Weinsaft1, Martin R. Prince1, Yi Wang1

1Weill Medical College of Cornell University, New York, New York, USA

The objective of this work was to compare the performance of the restrospective (RETRO), accept/reject (A/R), diminishing variance algorithm (DVA), and phase ordering with automatic windows selection (PAWS) gating techniques in SSFP 3D coronary MRA. Experiments were performed in 10 volunteers without breath coaching and 15 vessels were imaged. PAWS provided significantly better image quality than A/R (P=0.02), DVA (P=0.01) and RETRO (P=0.002). PAWS and DVA were the most efficient algorithms, providing an approximately 20% and 41% higher navigator efficiency compared to A/R (P=0.01) and RETRO (P<0.001).

                  945.       Navigator Echo Biofeedback (NEB) Significantly Increases Navigator Efficiency in Coronary MR Imaging

Sebastian Feuerlein1, Martin Jeltsch2, Oliver Klass2, Hans-Juergen Brambs2, Martin HK Hoffmann2

1University of Ulm, Ulm, Germany; 2University of Ulm, Germany

The aim of our study was to investigate whether a modern respiratory biofeedback system using different diaphragm positions and supplemental oxygen could significantly increase navigator efficiency while maintaining image quality compared to conventional respiratory gated MRCA.According to our initial experiences such a Navigator Echo Biofeedback significantly increases navigator efficiency and thereby decreases total imaging time by about 40% compared to a conventional free breathing acquisition strategy.


Myocardial Perfusion

Hall D                                   Thursday 13:30-15:30

                   995.       Automated Breathing Motion Correction in First-Pass Myocardial Perfusion MRI

Julien Milles1, Rob J. van der Geest1, Michael Jerosch Herold2, Johan HC Reiber1, Boudewijn PF Lelieveldt1

1Leiden University Medical Center, Leiden, Netherlands; 2Brigham & Women's Hospital, Boston, USA

In this work, we present a fully automatic algorithm for registration of perfusion data that is robust against the large contrast variations during bolus passage, and does not require manual interaction or ROI definition. Validation experiments on 45 MR perfusion studies demonstrate: 1)a high robustness, 2)a substantial reduction in LV center motion after registration, with an average motion of 0.64 ± 0.46 pixel, 3)an increase in the percentage of studies with a motion below 1 pixel from 32% before to 88% after registration and 4)a substantial improvement due to registration of the correlation and NMSE of perfusion curves compared to manually derived perfusion curves. We conclude that the ICA-based registration shows an excellent accuracy, robustness and computation speed, adequate for use in a clinical environment.

                  996.       3D HYPR-Based MRI Techniques for Myocardial Perfusion Imaging

Orhan Unal1, 2, Julia Velikina1, Charles A. Mistretta1

1University of Wisconsin, Madison, Wisconsin, USA

In myocardial perfusion imaging, the goal is to differentiate contrast kinetics of normal and ischemic myocardium. The required high temporal resolution does not allow for acquisition of a fully sampled dataset in each time frame. As a result, reconstructed images suffer from loss of spatial resolution and/or low signal-to-noise ratio (SNR) and undersampling artifacts. Recently developed HighlY constrained backPRojection (HYPR)-based techniques in combination with a hybrid radial/Cartesian acquisition can provide relatively artifact free images with high SNR and high temporal resolution for large undersampling factors.

                  997.       Arterial Spin Labeled Myocardium Perfusion Imaging with Background Suppression

Zungho Zun1, Eric C. Wong2, Krishna S. Nayak1

1University of Southern California, Los Angeles, California , USA; 2University of California, San Diego, La Jolla, California , USA

We demonstrate myocardial perfusion imaging at 3 T using arterial spin labeling with background suppression. The measured perfusion rate follows a non-central chi distribution as verified by experiments. The number of averages that provides quantification of myocardial blood flow with a specific percentage confidence interval is roughly 200 times greater than that required for ASL cerebral blood flow measurement with the same confidence. ASL cardiac perfusion imaging is demonstrated in healthy volunteers with measured myocardial blood flow values matching literature values.

                  998.       3D First-Pass Myocardial Perfusion Imaging at 3T: Towards Complete Left Ventricular Coverage

Taehoon Shin1, Houchun Harry Hu1, Samuel S. Valencerina2, Gerald M. Pohost1, Krishna S. Nayak1

1University of Southern California, Los Angeles, California , USA; 2Tenet Healthcare, Los Angeles, California , USA

Inadequate spatial coverage of the left ventricle in current 2D multi-slice first-pass myocardial perfusion imaging (MPI) limits the complete assessment of under-perfused volume.  In this work, we investigate 3D MPI, an attractive alternative that provides contiguous volumetric coverage as well as greater signal-to-noise ratio efficiency.  In healthy volunteers, we demonstrate 3D MPI with 2D parallel imaging at 3 Tesla. Complete coverage of the left ventricle in diastole with 3x4.5x10 mm3 spatial resolution is achieved.  Excellent image quality was obtained, allowing semi-quantitative analysis and visualization of perfusion indices across the whole heart.

                  999.       Towards Non Contrast Agent Myocardial Perfusion Imaging Using Spin-Echo Based Images with Blood
                                Oxygenation Level Dependent Contrast at 3.0 T

Uwe Heinrichs1, Tobias Frauenrath1, Jane Francis Utting1, Gabriele A. Krombach1, Rolf W. Günther1, Thoralf Niendorf1

1University of Aachen, University Hospital, Aachen, Germany

This study examines the feasibility of free breathing, black blood prepared, cardiac gated spin echo based imaging (UFLARE) at 3.0 T to generate BOLD contrast and T2*-maps of the myocardium, without geometric distortions. Phantom and volunteer studies demonstrate the geometrical integrity and high image quality obtained with UFLARE - even for strong T2*-weighting. Results show that T2*-weighted UFLARE may present a realistic alternative to contrast agent studies of myocardial perfusion, which avoids the drawbacks of EPI and gradient echo based imaging. Furthermore, the approach may be extended to map T2*, quantify myocardial iron content, and assess endothelial function. 

                  1000.     Quantitative Myocardial Perfusion Imaging Using Different TSENSE Accelerated Pulse Sequences

Stefan Weber1, Andrea Kronfeld1, R. Peter Kunz1, Kerstin Münnemann1, Georg Horstick1, Karl Friedrich Kreitner1, Wolfgang G. Schreiber1

1Mainz University Medical School, Mainz, Germany

Quantitative first-pass myocardial perfusion imaging was performed using three TSENSE-accelerated (R=2) pulse se-quences (SR-TrueFISP, SR-TurboFLASH and SR-segEPI). Myocardial blood flow (MBF) was calculated using XSIM using the MMID4 model. All calculated MBF values were the in range expected for young healthy volunteers. However, SR-TurboFLASH and SR-segEPI yielded significant smaller MBF values than SR-TrueFISP. Furthermore, MMID4-fit quality was considerably lower using the SR-TurboFLASH or SR-segEPI pulse sequence compared to SR-TrueFISP. Therefore, under the shown experimental setting SR-TrueFISP seems to be the method of choice for quantitative myocar-dial perfusion imaging.

                  1001.     Steady State Free Precession (SSFP) Cardiac 1st Pass Perfusion MRI: Left Ventricular Blood Pool
                                Saturation Effects and Considerations at 1.5T

Jens Vogel-Claussen1, Kakuya Kitagawa1, Joao A.C. Lima1, David A. Bluemke1

1Johns Hopkins Hospital, Baltimore, Maryland, USA

Traditionally gadolinium contrast is administered on a weight-based dosing scheme (mmol/kg). The purpose of this study was to evaluate the impact of this traditional weight-adjusted dosing scheme on the myocardial blood pool contrast concentration for quantitative analysis of first pass perfusion MRI. Traditional weight-adjusted dosing scheme for quantitative analysis of first pass SSFP perfusion MRI using 0.075mmol/kg does not result in uniform left ventricular blood pool contrast concentration. At doses >11ml gadopentetate dimeglumine the T2 effects appear to artificially decrease the measured LV contrast concentration, which cannot be fully corrected by the test bolus.

                  1002.     Multi-Modal Cardiac MRI Monitoring of the Effect of Isoproterenol on Myocardial Perfusion, Function
                                and Morphology

Frank Kober1, Mark Cole2, Martine Desrois1, Carole Lan1, Patrick J. Cozzone1, Kieran Clarke2, Monique Bernard1

1CNRS UMR N  6612, Faculté de Médecine, Université de la Méditerranée, Marseille, France; 2University Laboratory of Physiology, Oxford, UK

Isoproterenol is a beta-adrenoreceptor agonist used in animal models to study the mechanisms of cardiac hypertrophy and failure. In this longitudinal CMR study, time-dependent changes in myocardial perfusion were assessed by arterial spin labeling along with morphologic and functional parameters using multimodal cardiac MRI during continuous administration of IP over 7 days. Multimodal MRI has shown that hypertrophy during IP administration is preceded by strong MBF increase and that cardiac function is maintained on a high level even at day 7. This indicates a mismatch between cardiac function and perfusion that might play a major role in the process of ventricular adaptation.

                  1003.     Linear Arterial Input Functions for First-Pass Myocardium Blood Flow Assessment Using Calibration
                                and Bloch Simulation

Glenn Reynolds1, Micheal Jerosch-Herold2, Sandeep N. Gupta3

1GE Healthcare, Boston, Massachusetts, USA; 2Brigham and Women's Hospital, Boston, Massachusetts, USA; 3GE Global Research Center, Niskayuna, USA

Quantitative techniques, such as Fermi analysis, are used to assess ischemic regions of the myocardium and require Arterial Input Functions (AIF) and Myocardial Response Functions (MRF). First-pass perfusion imaging, using a single bolus of Gadolinium (Gd) contrast agent, results in a linear Myocardial Response Function and a less than linear Arterial Input Function. The purpose of this study is to demonstrate a method to generate a linear AIF using a combination of imaging, calibration, and Bloch simulation.

                  1004.     Computational Fluid Dynamics Analysis of Bolus Dispersion in Myocardial Perfusion Measurements

Dirk Graafen1, Kerstin Münnemann1, Stefan Weber1, Wolfgang G. Schreiber1

1Mainz University Medical School, Mainz, Germany

Using Computational Fluid Dynamics methodology dispersion of a contrast agent bolus was simulated in a straight vessel with different stenoses under steady state conditions. Two different perfusion conditions were examined: resting condition (inlet-velocity v = 0.1m/s) and stress condition (constant inlet-pressure p = 1010 Pa) both realizing a myocardial perfusion reserve of 5 in the absence of a stenosis. The dispersion in resting condition is greater than under stress conditions. Therefore, resting myocardial blood flow may be more underestimated in quantitative myocardial perfusion studies than stress perfusion.

                  1005.     Detection of Coronary Artery Disease with Both Myocardial Blood Flow and Volume:

Kyle Stephan McCommis1, Thomas A. Goldstein1, Robert J. Gropler1, Jie Zheng1

1Washington University School of Medicine, St. Louis, Missouri, USA

A newly developed quantitative MR perfusion technique was evaluated in normal and stenotic dogs, at rest and during Dipyridamole or Dobutamine-induced hyperemia. Myocardial perfusion maps were constructed to assess changes in both myocardial blood flow (MBF) and volume (MBV). Stenosis caused gradual attenuations of both hyperemic MBF and MBV in the stenosis subtended region. Interestingly, these parameters were also attenuated in the normal remote myocardial regions. These effects may imply coronary steal and auto-regulation, but further study is necessary. Measurements of both MBF and MBV may allow for more comprehensive diagnoses of coronary artery stenosis and better treatment planning.

                  1006.     Inline Perfusion – a New Approach for Fully Automated Generation of Semi-Quantitative Parameter
                                Maps Integrated Into Image Reconstruction

Sven Zuehlsdorff1, Tongbai Meng2, Ying Sun3, Peter Kellman4, Jens Guehring5, Sonia Nielles-Vallespin6, Christine H. Lorenz2, Renate Jerecic1

1Siemens Medical Solutions USA, Inc., Chicago, USA; 2Siemens Corporate Research, Inc., Baltimore, USA; 3National University of Singapore, Singapore, Singapore; 4National Institutes of Health/NHLBI, Bethesda, USA; 5Siemens Corporate Research, Inc., Princeton, USA; 6Siemens AG Medical Solutions, Erlangen, Germany

The clinical use of first-pass MR myocardial perfusion imaging has shown a significant increase over the last years due to improved image quality and overall increased sequence performance in terms of spatial resolution and speed. Semi-quantitative or quantitative analysis of perfusion images usually requires significant user interaction and expertise that results in prohibitive long times to evaluate myocardial perfusion images. The goal of this work was to implement and test a framework for inline perfusion analysis which completely eliminates the need for user interaction and presents semi-quantitative parameter maps immediately after the scan together with the reconstructed images. The framework was tested on volunteers and patients. The feasibility of a fully automated perfusion analysis was demonstrated.

                  1007.     Effects of Blood Fraction and Noise on a Model-Independent Deconvolution Method for Estimating
                                Myocardial Blood Flow

Nathan Allen Pack1, 2, Edward VR DiBella1

1University of Utah, Salt Lake City, USA

A model-independent deconvolution method, which uses iterative minimization and regularization to estimate the impulse response and myocardial blood flow from dynamic contrast-enhanced MRI perfusion images, was evaluated.  Variations in the delay time between blood and tissue enhancement changed flow estimates up to 10%. The inclusion of a vascular blood signal was found to linearly increase estimates of blood flow using this deconvolution method.  The use of model-independent analysis with noisy pixelwise dynamic MRI perfusion data resulted in flow estimates ~12% higher than flow estimates from large (200 pixel) regions.


Myocardial Viability Methods & Applications

Hall D                                   Thursday 13:30-15:30

                   1036.     Improved Dark Blood Delayed Enhancement Imaging with Triple IR Preparation

Wolfgang G. Rehwald1, Michael Salerno, Enn-Ling Chen, Robert M. Judd, Raymond J. Kim

1Siemens Medical Solutions, Chapel Hill, North Carolina, USA

We developed a dark blood delayed enhancement technique for MR imaging of myocardial viability employing a triple IR preparation. We implemented the method on a 1.5T clinical MRI scanner and evaluated it in dogs. The contrast between infarct and blood pool improved dramatically compared to the clinical gold standard (GS) while still providing adequate infarct SNR. Compared to previous double-preparation dark blood techniques timing was more flexible and SNR was improved. The slice-selective inversions and readout could be played when the heart was in a similar position providing a homogeneous preparation and reliable blood signal suppression.

                  1037.     Cardiac MRI: How Much Myocardial Damage is Necessary to Detect Focal Late Gadolinium Enhancement?
 [Not Available]

Kai Nassenstein1, Frank Breuckmann2, Christina Bucher1, Gernot Kaiser2, Thomas Konorza2, Gerd Heusch3, Joerg Barkhausen1

1University Hospital Essen, Essen, Germany; 2Universitiy Hospital Essen, Germany; 3University Hospital Essen, Germany

Detection of structural myocardial abnormalities in non-ischemic diseases is difficult by cardiac MRI, because non-ischemic diseases typically cause multifocal myocardial damages and affect only a small amount of myocardium. To estimate how much myocardial damage is necessary to detect focal myocardial lesions by late enhancement, experimental coronary microembolization was performed in 18 pig as a model for a multifocal myocardial pathology. Our results show, that focal myocardial lesions exceeding 5% of myocardium per section could be detected in vivo by late gadolinium enhancement in 86%.

                  1038.     Late Gadolinium Enhancement Imaging with Automatic Establishment of the Optimal Inversion Delay

J.B.M. Warntjes1, 2, J. Kihlberg1, J. Engvall1

1Center for Medical Imaging Science and Visualization (CMIV), Linköping, Sweden; 2Division of Clinical Physiology, Linköping, Sweden

To establish the optimal inversion delay time for inversion recovery images in a Late Gadolinium Enhancement examination is challenging. The optimal delay time depends on many factors such as patient weight, contrast dose and time after contrast injection. A method is presented that allows to visualize LGE images with an inversion delay time that is free to choose. All these images are based on a single breath-hold scan. The procedure is implemented into the PACS visualization software and helps to interactively find the optimal inversion delay for all subsequent MR scans.

                  1039.     Automatic Detection and Quantification of Non-Viable Myocardium in Late Enhancement Images

Anja Hennemuth1, Achim Seeger2, Ola Friman1, Stephan Miller2, Heinz-Otto Peitgen1

1MeVis Research, Bremen, Germany; 2University Hospital Tübingen, Tübingen, Germany

Late enhancement imaging is proven to be suitable for the assessment of myocardial infarctions. The purpose of our work was the development and evaluation of an automatic and thus reproducible method to detect and quantify non-viable tissue in short axis late enhancement images. The developed methods are based on an intensity distribution model combined with a watershed segmentation. For evaluation 15 datasets were segmented by experts, with the common 3s-method and with the new automatic algorithms. Segment-based volume analysis correlated well for automatic and manual segmentations but not for 3s-results. Overlap comparisons also indicate the appropriateness of the developed algorithms. Further improvements are possible by consideration of long axis images

                  1040.     A Rician-Gaussian Mixture Model for Segmenting Delayed Enhancement MRI Images

Ola Friman1, Anja Hennemuth1, Heinz-Otto Peitgen1

1MeVis Research, Bremen, Germany

A Rician-Gaussian mixture model for segmenting scarred tissue in delayed enhancement MRI images is presented. The parameters in the mixture model are fitted using the Expectation-Maximization algorithm, which also is detailed in the abstract. It is shown that the Rician-Gaussian model fits well, as is predicted by theory. However, partial volume effects due to the large voxel size in delayed enhancement images broaden the fitted distributions. Future work to combat the influence of partial volume effects involves extending the mixture model and introducing spatial context via a Markov Random Field.

                  1041.     Evaluation of Patients with Suspected Cardioembolic Stroke Using Cardiovascular MRI - A Comparative
                                Study with Echocardiography

John J. Sheehan1, George Lin1, Jim Conners1, Mark J. Alberts1, Karin Dill1, Reed A. Omary1, Richard A. Bernstein1, James C. Carr1

1Northwestern University, Chicago, USA

CVMR is a non invasive method for the detection of intracardiac thrombi and is clinically advantageous in the detecting non thrombotic findings, including prothrombotic conditions. 106 patients with a suspected CES had CVMR for the detection of intracardiac thrombi. CVMR revealed 10 thrombi in n=9  patients. In 9 patients echocardiography was positive in n=2, indeter. in n=2 and negative in n=5. Additional findings associated with thrombus formation were n=19 (20%) for CVMR and n=7 (7%) for echocardiography.  CVMR should be considered as part of the routine evaluation with echocardiography in the assessment of patients with suspected CES.

                  1042.     Correlation and Visualization of Left Atrial Scar Due to Pulmonary Vein Ablation with Recorded Ablation

Jason E. Taclas1, John V. Wylie1, Reza Nezafat1, Thomas H. Hauser1, Mark E. Josephson1, Warren J. Manning1, Dana C. Peters1

1Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA

Radio frequency pulmonary vein ablation is a treatment for atrial fibrillation which provides an electrical block between the left atrium and the pulmonary veins.  Electroanatomic mapping system CARTOMERGE (Biosense, Webster) records sites of RF application, and registers these sites to angiographic data in real time to help guide the procedure.  After the procedure, late gadolinium enhancement (LGE) cardiovascular MR can be used to image scar generated by RF ablation.  We have developed a tool using Visual Toolkit (Kitware Inc.) to register electroanatomic mapping data to angiographic data, and render it with LGE scar data. 

                  1043.     Application of DE-MRI to Assess the LA Myocardium Composition in AF Patients

Robert S. Oakes1, 2, Eugene Kholmovski3, 4, Edward V.R. DiBella3, 4, Nathan Segerson4, Eric Nathaniel Fish4, Christopher J. McGann4, Rob S. MacLeod2, 4, Nassir F. Marrouche5

1University of Utah School of Medicine, Salt Lake City, USA; 2University of Utah, Salt Lake City, USA; 3Utah Center for Advanced Imaging Research, Salt Lake City, USA; 4University of Utah Schol of Medicine, Salt Lake City, USA; 5University of Utah Schol of Medicine, Salt Lake, USA

We report an MRI method to define responders to pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF).  Thirty one patients were imaged using a delayed enhancement MRI scan protocol.  Novel image processing methods were then applied to visualize and quantify the amount of enhancement in two and three dimensions.  Patients with extensive enhancement on MRI were much more likely to suffer recurrence than patients without enhancement.  MRI appears to offer a feasible way to define areas of fibrosis in patients with AF and shows great promise in predicting responders to PVI treatment.

                  1044.     Temporal Evolution of Myocardial Perfusion, Viability and Function After Intramyocardial Transfer
                                of Plasmid  DNA Gene Expressing Two Isoforms of Hepatocyte Growth Factor

Maythem Saeed1, Alastair J. Martin1, Phlilip Ursell1, Loi Do1, Matthew Bucknor1, Charles B. Higgins1, David Saloner1

1University of California San Francisco, San Francisco, California , USA

Cardiac dysfunction in ischemic cardiomyopathy is most likely due to decreased perfusion and increased collagen synthesis. Therefore, an approach that alters perfusion and fibrosis may open up a new therapeutic avenue. Accordingly, we investigated the angiogenic and antifibrotic effects of intramyocardially delivered hepatocyte growth factor (HGF) gene in acute infarction. Perfusion and viability MR imaging was used to non-invasively assess the therapy. Histopathological methods were used to confirm MR findings. Our novel study demonstrated the biological effects of HGF gene in infarcted myocardium. The beneficial effect of HGF gene includes angiogenesis and formation of peninsulas/islands of viable cells in peri-infarcted myocardium. The MR study provides comprehensive assessment of myocardial perfusion, viability and function after gene therapy.


RF Transmit Array Methods

Hall D                                   Thursday 13:30-15:30

                   1081.     Analysis of Coil Configurations for Transmit SENSE

Glen Morrell1

1University of Utah, Salt Lake City, USA

A framework is presented for evaluation of coil configurations for transmit SENSE.  For subsampled Cartesian k-space, a matrix A of coil sensitivity values is inverted at each spatial location to calculate the individual per-coil excitation profiles which add to give the desired excitation.  We show through mathematical analysis and Monte Carlo simulation that the condition number of A, evaluated point by point in the spatial domain, is a good measure of the fidelity of excitation that can be achieved by a transmit SENSE coil configuration in the presence of noise in the coil sensitivity profiles.

                  1082.     Q Measurement and Simulation for RF Coils

Geoff Jacobs1, Abel Assefa1, Jacob Willig-Onwuachi1

1Grinnell College, Grinnell, USA

While Q measurements are used widely to characterize RF coils and the theory involved is well understood, there is surprisingly little literature on how to most accurately perform these measurements.  This project is an initial attempt to compare several common methods of measuring Q with each other and with expected theoretical results.  A basic model for simulation is presented.

                  1083.     Selective Excitation Without Gradients with Accelerated TRASE

Jonathan C. Sharp1, Scott B. King2, Donghui Yin2, Vyacheslav Volotovskyy2, Boguslaw Tomanek1

1National Research Council Institute for Biodiagnostics, Calgary, Canada; 2National Research Council Institute for Biodiagnostics, Winnipeg, Canada

The abstract shows how slice selection can be achieved using only pair of RF coils and a single-channel transmitter system. This method uses two or more uniform amplitude RF volume coils designed with B1 phase gradients. A train of refocusing pulses, applied alternately between the two coils, provides a k-space trajectory. Interleaved small tip angle pulses with a sinc envelope results in slice selection. In addition, the method may be accelerated to reduce the echo train length by use of two or more coils for the small tip angle pulses following each refocusing pulse.

                  1084.     B1-Shimming at 3T Using an 8-Channel Transmit Array

Scott B. King1, Mike J. Smith1, Ulrich Fontius2, Peter Latta1, Jarod Matwiy1, Franz Schmitt2, Boguslaw Tomanek1

1Institute for Biodiagnostics, Winnipeg, Canada; 2Siemens Medical Solutions, Erlangen, Germany

B1-shimming can be accomplished with hardware-only using a transmit-array with appropriately driven amplitude and phase of each array element, or using 2D/3D RF spatially selective pulses.  On a new Siemens 8-channel transmitter 3T Trio-Tim MRI system, we have shown that B1-shimming using the hardware approach using an azimuthal distribution of array elements is unable to adequately achieve uniform excitation and therefore future Tx-array coils will require elements to be placed along the axis of the coil as well.  2D/3D RF pulses can effectively produce uniform excitation but require Tx-arrays (Tx-SENSE) to minimize acceptable pulse lengths.

                  1085.     B1 Transmit Field Correction at 7T Using Coupled Inner Elements

Hellmut Merkle1, Shumin Wang1, Peter van Gelderen1, Tie Q. Li1, Joseph Murphy-Boesch1, Alan P. Koretsky1, Jeff H. Duyn1

1National Institutes of Health, Bethesda, Maryland, USA

Multiple resonant loop elements placed within the interior of a circularly polarized volume transmit coil have been used to modify the field profile over a conductive phantom.  The phantom has been filled with low dielectric material and saline to approximate the dielectric and conductive properties of the head.  A B1 mapping sequence has been used to provide quantitative information about the modified transmit B1 field.

                  1086.     Improved Parallel Imaging Using Small FOV Excitation on an 8-Channel Transmit Array System

Mike J. Smith1, Scott B. King1, Peter Latta1, Jarod Matwiy1, Ulrich Fontius2, Franz Schmitt2, Boguslaw Tomanek1

1National Research Council Institute for Biodiagnostics, Winnipeg, Canada; 2Siemens Medical Solutions, Erlangen, Germany

Transmit array systems can generate better 2D excitation profiles in shorter time than single channel transmitters. We used our new 3T Siemens 8-channel transmit system in enhancing parallel imaging when the sample exceeds the ROI. When excitation artifact signals are below the image noise level, g-factor maps are significantly improved, and effective reduction factors larger than the receive array are possible.

                  1087.     Subject-Dependent Optimization of Parallel RF Transmission for High-Field MRI  [Not Available]

Yeun Chul Ryu1, Jung Ho Hyun1, Jong Soek Oh1, Yong Gwon Kim1, Soo Yeol Lee2, Heung Kyu Lee3, Chang Hyun Oh1

1Korea University, Seoul, Republic of Korea; 2Kyung-Hee University, Suwon, Republic of Korea; 3KAIST, Dae-jeon, Republic of Korea

A Subject-dependent rapid RF field mapping method for parallel RF transmission.

                  1088.     Transmit B1 Shimming at High Field with SAR Constraints: A Two Stage Optimization Method
                                 Independent of the Initial Set of RF Phases and Amplitudes

Tsung-Hui Chang1, Zhi-Quan Luo1, Xiaoping Wu2, Can Akgun2, Thomas Vaughan2, Kamil Ugurbil2, 3, Pierre-Francois Van de Moortele2

1University of Minnesota, Minneapolis, Minnesota, USA; 2University of Minnesota Medical School, Minneapolis, Minnesota, USA; 3Max Planck Institute for Biological Cybernetics, Germany

There has been an increasing interest in constraining transmit B1 shimming with specific absorption rate (SAR) limits, especially at high magnetic field. Since most of the existing methods rely on solving a nonconvex optimization problem, they are typically faced with two difficulties: Only local optimum solutions are obtained, and they are susceptible to the chosen initial points for optimization. Here we introduce a two stage optimization method where a reliable initial point is acquired in the first stage by a convex semidefinite relaxation (SDR) approximation method. A high quality B1 shimmed map then can be obtained in the second stage optimization using the SDR initial points. The presented technique is verified with simulations for a 16-channel transmit coil array at 7T with a human head model.


RF Systems & Components

Hall D                                   Thursday 13:30-15:30

                  1119.     An MRI System with 128 Seamlessly Integrated Receive Channels for Multi-Nuclear Operation  [Not Available]

Bernd Stoeckel1, Andreas Potthast1, Niels Oesingmann1, Daniel Sodickson2, Ray Lee2, Davide Santoro2, Glyn Johnson2, Thomas Heumann3, Thomas Arnold3, Michael Wullenweber3, Matthias Buettner4

1Siemens Medical Solutions USA, Inc., New York, New York, USA; 2Center for Biomedical Imaging, New York, New York, USA; 3Siemens Medical Solutions, Inc., Erlangen, Germany; 4Astrum IT, Erlangen, Germany

We present the expansion of a commercially available Siemens 3T MR scanner to a system, which enables the online acquisition and reconstruction of images from up to 128 receive channels and which offers multi-nuclear capabilities. The combination of hyperpolarization and a very high number of receive elements is very interesting for two reasons: The initially available SNR is increased and the SNR loss traditionally associated with accelerated parallel imaging may be mitigated or even eliminated. As an example first volunteer lung images with hyperpolarized helium are shown which were acquired with a 128 element receive array at 3He frequency.

                  1120.     Analog Optical Transmission of 4 MRI Receive Channels with High Dynamic Range Over One Single
                                 Optical Fiber

Stephan Biber1, Peter Baureis2, Jan Bollenbeck1, Phillip Höcht1, Hubertus Fischer1

1Siemens Medical Solutions, Erlangen, Germany; 2University of Applied Sciences Wuerzburg Schweinfurt, Germany

A new prototype system for analog optical signal transmission between local coil and the receiver is presented in this paper. The system allows to transmit 4 MRI receiver signals on the same optical fiber and implements an optical link with high dynamic range using low cost vertical cavity surface emitting laser diodes (VCSEL). The advantage of an optical transmission concept is the fact that large bundles of copper cables including cable traps for shield wave suppression can become redundant.

                  1121.     Design of Digital Wireless Transmission for 64 Channel Array Using IEEE 802.11n  [Not Available]

Gary X. Shen1, Juan Wei, Yong Pang

1The University of Hong Kong, Hong Kong, People's Republic of China

This work investigates MRI application using the recent developed technology of WLAN 802.11n (draft) for multiple RF channel EPI. The number of RF channel, signal dynamic range, bandwidth, ADC sampling rate, direct digital synthesizer and digital signal processing control are analyzed and discussed in detail.  FDM modulation is used to increase the number of RF channels before ADC. The theoretical analysis and bench test results show that 802.11n can be used for ultra-fast EPI (20 images/s) with 64 RF channels. The MR signal dynamic range could be up to 120 dB.

                  1122.     A Preamplifier for 7T MRI with Extended Dynamic Range and Integrated Cable Trap

Klaus Markus Huber1, Martin Hemmerlein1, Stephan Biber1, Ralph Oppelt1, Karsten Wicklow1

1Siemens AG, Erlangen, Germany

The new 7T preamplifier is capable of handling input powers of up to -15.6dBm although consuming less than 250mW of dc power. Its noise figure is as low as 0.6dB. An integrated cable trap suppresses common mode signals and thus makes the design of high channel array coils much easier. The actual size of the amplifier PCB is only about 41mm x 18mm. With a first 3-channel array equipped with the new preamplifiers, outstanding signal to noise ratios have been achieved in a Siemens 7T MRI-system.

                  1123.     Influence of Magnetic Field on Preamplifiers Using GaAs FET Technology

Cecilia Possanzini1, Marco Boutelje1

1Philips Medical Systems, Best, Netherlands

In this paper, we show the influence of magnetic field on preamplifiers carrying a GaAs FET (field effect transistor). The S-parameters of the amplifier are measured with magnetic field parallel and perpendicular to the carriers in the FET and compared with data at zero magnetic field. The difference in behaviour of the preamplifier with and without magnetic field can be explained by the occurrence of Hall effect.

                  1124.     Preamp Decoupling - Eigenvalue Solution Approach

Victor Taracila1, Keerthi Shet2, Fraser Robb1

1GE Healthcare, Aurora, USA; 2Ohio State University, Columbus, USA

The most modern decoupling method is the preamp decoupling, which consists in bringing a low impedance preamp as close as possible to the coil element and inserting it into a parallel resonance trap which itself is in series with the coils element. This method allows decoupling of the coil elements placed far from each other, which exhibits week coupling and cannot be decoupled by other means. Although there are many interpretation of this techniques based on transmission line theory, we consider that an eigenvalue interpretation is closer to the multiple-degree electrical oscillator, which the MR RF coil represents par excellence.

                  1125.     Optimizing Artwork Cross-Section for Surface RF Coils

Victor Taracila1, Fraser Robb1

1GE Healthcare, Aurora, USA

At high frequency the current flows only on the surface of the conductor due to the well known skin effect, the excess of copper will not lower the noise coming from the coil itself. Moreover, very large copper strips will shield the subject (object) under study from transmit RF field introducing significant B1 field distortion. This problem can be solved for one dimension and even two dimensions for a rectangular cross-section using complicate mathematical methods. Presented method is simpler and can easily be applied to any cross section of the copper strip.

                  1126.     Can Inkjet Printing Produce MRI Coils?

Patrick J. Smith1, Dario Mager1, Ute Loeffelmann1, Jan G. Korvink1

1University of Freiburg, Freiburg, Germany

To the knowledge of the authors, inkjet printing has not yet been used to produce MRI RF transmit and receive coils, possibly because of the variability of the fabrication technology, and the lack of low resistivity metal-containing inks. In this paper, we discuss the questions and responses facing an inkjet-based processing route for MRI coils, and report on the experimental steps that have been undertaken to demonstrate the veracity of the answers. 

                  1127.     Ultra Low Susceptibility PIN Diodes for High Field

Ronald D. Watkins1, William Doherty2, Pavel Voskoboynik

1Stanford Medical School, stanford, California , USA; 2MicroSemi Corp, Lowell, USA

Authors here have developed and demonstrated greatly improved RFPIN Diode components for reducingsusceptibility artifacts at high field

                  1128.     Spurious Proton Signal from Phased Array Coil Materials- How Much Proton Signal is Too Much?

Victor Taracila1, Fraser Robb1

1GE Healthcare, Aurora, USA

A receive RF coils contains material like Kapton™ tape, Delrin™ rods, Polycarbonate, Nylon etc., which do contain a certain amount of proton signal. The ideal situation would be to eliminate completely all Hydrogen from all building components. However, it could be costly and sometimes unnecessary if the amount and relaxation times T1 and T2 are correlated with existing gradient slew rates, RF pulse width and the very matter we intend to image – living organisms.

                  1129.     MRI Dynamic Range: Theory and Measurement

Refaat E. Gabr1, Michael Schar1, 2, Arthur D. Edelstein3, Paul A. Bottomley1, William A. Edelstein1

1Johns Hopkins University, Baltimore, Maryland, USA; 2Philips Medical Systems, Cleveland, Ohio, USA; 3University of California, Berkeley, Berkeley, California , USA

We have undertaken MRI dynamic range (DR) measurements in order to determine compatibility of MR multicoil images with fiber optic signal transmission. Our results indicate that such links should be viable at 3T and possibly higher.


MR-Guided Interventions (Non-Thermotherapy)

Hall D                                   Thursday 13:30-15:30 

                  1197.     Cardiovascular MR Imaging is a Platform for Percutaneous Transendocardial Delivery and Assessment
                                of Gene Therapy

Maythem Saeed1, Alastair J. Martin1, Alexis Jacquier1, Loi Do1, Matthew Bucknor1, Charles B. Higgins1, David Saloner1

1University of California San Francisco, San Francisco, California , USA

MR fluoroscopy was used for guiding transendocardial delivery of plasmid VEGF and for evaluating myocardial perfusion, viability and function in occlusive infarction. A mixture of plasmid VEGF and LacZ or plasmid LacZ and Dy-DTPA-BMA were delivered into the border and core of MR hyperenhanced infarcted region. At 7-8 wks, plasmid VEGF increased ejection fraction, perfusion, vascularity and decreased infarcted region on MR imaging and histochemical staining. MR imaging was successfully used in guiding delivery of genes and assessing myocardial viability and function. The effectiveness of this approach most likely stems from VEGF effects on neovascularization in scar tissue.

                  1198.     MR-Guided Biopsy Targeting Transplanted MR-Visible Magnetocapsules (MCs) Containing Human Islets

David Arthur Woodrum1, Thomas Link2, Wesley D. Gilson2, Christine H. Lorenz2, Dara L. Kraitchman2, Jeff WM Bulte2, Aravind Arepally2

1Mayo Clinic, Rochester, Minnesota, USA; 2Johns Hopkins University School of Medicine, Baltimore, Maryland, USA

Magnetic resonance (MR)-trackable magnetocapsules (MCs) were created to simultaneously immunoprotect pancreatic beta cells and non-invasively monitor, in real-time, portal vein delivery and engraftment using MR imaging (MRI). The purpose of this study was to demonstrate the feasibility of MR-guided targeted biopsy of MCs containing human islets to assess viability and function.  MR-compatible 14g biopsy needle was tracked (using a passive artifact from the needle) and steered into the four quadrants of the  liver using  a real-time sequence through a percutaneous access. By utilizing MRI, needle placement close to the MCs was ensured and core biopsies were obtained.

                  1199.     Endoluminal In-Vivo High-Resolution MR Imaging of the Esophageal Wall with Histological Correlation

Sherif G. Nour1, 2, Jens O. Heidenreich1, Jamal J. Derakhshan, Simi Paul1, Fadi W. Abdul-Karim1, Mark A. Griswold1, Vikas Gulani1, John Jesberger, Philip A. Linden1, Jeffrey L. Duerk1

1University Hospitals Case Medical center / Case Western Reserve University, Cleveland, Ohio, USA

Esophageal cancer affects 5/100,000 people in the USA.  5-year survival rate is <10% despite therapeutic advances. Accurate staging and appropriate treatment rely on determining the depth of tumor invasion through the esophageal wall. Here, a catheter-mounted receiver coil was used to obtain in-vivo high-resolution images of esophageal wall. The performance of various MR-pulse sequences was tested, imaged segments were harvested, and images were correlated with histology. Results show that high-resolution esophageal wall MRI is feasible with commercially-available imaging catheters and there is high correlation with histology in delineating various layers of normal esophageal wall as required for future MR staging.

                  1200.     PSIF Imaging with Outer Volume Suppression for Percutaneous Interventions

Jaane Rauschenberg1, Wolfhard Semmler1, Michael Bock1

1Deutsches Krebsforschungszentrum (dkfz), Heidelberg, Germany

In percutaneous MR-guided interventions imaging can be significantly accelerated by inner volume excitation or outer volume suppression, which restricts the phase encoding FOV. The combination of outer volume suppression with steady state pulse sequences such as PSIF is challenging, as conventional suppression pulses lead to a violation of the steady state condition. Here, a new integrated outer volume suppression technique, which maintains the steady state, is presented and evaluated in phantom and volunteer experiments.

                  1201.     Image Fusion Techniques for Integrated MR-Endoscope System

Makiya Matsumoto1, Yuu Shoji1, Yuichiro Matsuoka2, Etsuko Kumamoto1, Kagayaki Kuroda2, 3, Toshiya Kaihara1

1Kobe University, Kobe, Japan; 2Institute of Biomedical Research and Innovation, Kobe, Japan; 3Tokai University, Hiratsuka, Japan

We have devised image fusion techniques for the integrated MR-endoscope system, in which real time MR scanning is performed with an intraluminal surface coil during endoscopic observation and surgery for gastrointestinal applications. To navigate the scope and to match the scope coordinates with that of the scanner, wireless resonators with Gadolinium-absorbed gel were developed. For the image fusion, the MR images were deformed numerically with a fifth order, two dimensional approximation function obtained from the optical distortion of the scope view, after appropriate Affine-transformations for scaling and trapezoidal conversion were applied.

                  1202.     Motion-Corrected Intravascular MRI with an Active Tracking Catheter

Ann-Kathrin Homagk1, Sven Müller1, Peter Hallscheidt2, Marc-Andre Weber1, Wolfhard Semmler1, Michael Bock1

1Deutsches Krebsforschungszentrum (dkfz), Heidelberg, Germany; 2University Heidelberg, Heidelberg, Germany

The present study proposes a method of acquiring intra-arterial images using additional MR tracking information. An imaging and tracking pulse sequence was implemented and tested on a healthy anesthetized pig. The position of the tracking catheter tip was continuously extracted from projection data to use them for retrospective gating of the acquired images. For motion compensation, a range of positions was defined which were accepted as input for the subsequent image calculation. A comparison between motion-corrected images and uncorrected images showed that the use of projection data for motion correction leads to a significant improvement in image quality.

                  1203.     3D MRI-Guided Passive Catheter Tracking and Visualization Using HYPR-Based Techniques

Orhan Unal1, 2, Julia Velikina1, Charles M. Mistretta1

1University of Wisconsin, Madison, Wisconsin, USA

Catheter tracking and visualization require both good spatial and temporal resolution.  Recently developed HighlY constrained back PRojection (HYPR)-based techniques in combination with radial or hybrid radial/Cartesian acquisition techniques provides relatively artifact free images with large undersampling factors and is therefore well-suited for  MRI-guided passive catheter tracking and visualization applications.

                  1204.     Reverse Polarization Method for Catheter Tracking: Phased Array Coil Studies and Real-Time TSENSE

Haydar Celik1, Michael A. Guttman2, Onur Kocaturk2, Christina Saikus2, Kanishka Ratnayak2, Anthony Faranesh2, Andrew Derbyshire2, Robert Lederman2, Ergin Atalar1, 3

1Bilkent University, Ankara, Turkey; 2National Institude of Health, Bethesda, Maryland, USA; 3Johns Hopkins University, Baltimore, Maryland, USA

In MRI-guided vascular interventions, visualization of interventional devices is rather difficult. For this purpose many tracking techniques have been developed. In one of these studies, reverse polarized signal was acquired using a receive-only birdcage coil in order to separate the anatomical information from a catheter which contains a receive coupled RF (RCRF) coil.In present work, the reverse polarization method has been implemented to phased array coils and real-time experiments have been conducted on phantom using TSENSE  algorithm. As a result, reverse polarization mode of image, which consists of the catheter, and color-coded image are obtained. In order to show safety profile, phantom heating experiments were conducted.

                  1205.     Automated Tracking of a Passive Endomyocardial Stiletto Catheter with Dephased FLAPS MRI:
                                A Feasibility  Study

Ioannis Koktzoglou1, 2, Sotirios A. Tsaftaris3, Sven Zuehlsdorff4, Debiao Li2, Aggelos K. Katsaggelos3, Rohan Dharmakumar2

1Evanston Northwestern Healthcare, Evanston, Illinois, USA; 2Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA; 3Northwestern University, Evanston, Illinois, USA; 4Siemens Medical Solutions, Chicago, Illinois, USA

Automated tracking of a passive stiletto catheter for regenerative myocardial therapy under the MR environment may improve the accuracy ofthe procedure. We report successful implementation of automated computer-assisted tracking for this purpose in a controlled phantom study.

                  1206.     Non-Excitory Steady-State Interference Elimination (NESSIE) MRI Fiducial Tracking

Donald W. McRobbie1, Marc Rea1

1Imperial College Healthcare NHS Trust, Charing Cross Hospital, UK

Inductively coupled fiducial markers have an inconsistent appearance on MR images.The Non-Excitory Steady-State Interference Elimination (NESSIE) pulse sequence has been developed to remove this imaging sequence dependence. The contrast of the fiducials can be controlled independently from the background anatomy using NESSIE pre-pulses, potentially improving MR tracking during interventions.

                  1207.     Catheter Visualization Using Rubber Bands and Ultrashort TE Imaging

Juergen Rahmer1, Sascha Krueger1

1Philips Research Europe, Hamburg, Germany

Increasingly, interventional procedures rely on MR imaging for tracking of catheters in the body. Active catheter visualization allows highlighting the tip position in a standard MR image, but requires additional equipment and dedicated catheters. In contrast, passive visualization requires only minimal device modification. Typically, susceptibility markers are attached to the device to cause local contrast in the image. However, this contrast effect is permanent and can negatively affect the anatomical information in the MR image. We propose to use short-T2 material with T2 shorter than about 1 ms as a passive marker. This material does not interfere with standard MR imaging, but can be visualized using ultrashort echo-time (UTE) sequences. This work demonstrates the passive visualization of the full catheter length using 3D UTE imaging of short-T2 rubber bands inserted into the catheter.

                  1208.     Rubber Materials for Active Device Tracking

Reiner Umathum1, Michael Bock1

1Deutsches Krebsforschungszentrum (dkfz), Heidelberg, Germany

Active device tracking is challenging in anatomical areas such as the lung where no MR signal is present. To overcome this limitation, a signal reservoir needs to be integrated into the tracking coil; however, these reservoirs require frequent re-filling. In this work we propose semi-solid rubber materials for MR tracking which are long-term stable. Due to their short T2* relaxation times, pulse sequences with ultra-short TE below 1 ms need to be used for device tracking.

                  1209.     A Novel Intravascular MRI Coil with Optimized Sensitivity

Stephan Fandrey1, Steffen Weiss2, Jörg Müller1

1Hamburg University of Technology, Hamburg, Germany; 2Philips Research Europe , Hamburg, Germany

A modified micro Helmholtz coil was designed for intravascular imaging and tracking with the objective to achieve maximum homogeneity of the coil sensitivity in the surrounding medium. The optimal design was determined using finite element simulations. Foil-based micro-Helmholtz-coils were fabricated with this design using planar micro systems technology and mounted on a 5F catheter tube. The sensitivity pattern of the coils was evaluated in phantom experiments and found to be conform with the simulation results. The use of micro systems technology allows coil fabrication in large batches with high reproducibility.

                  1210.     Ground Pad for Better Look-Ahead Visualization in Guidewire Imaging

Lizabeth Y. Li1, William R. Overall1, Greig C. Scott1, John M. Pauly1

1Stanford University, Stanford, California , USA

We apply the use of a grounding pad in combination with a wire receiver antenna to increase signal intensity in front of the wire tip for use in interventional MRI, offering a significant improvement in look-ahead visualization over a guidewire receiver antenna only.  The ground pad directs the current density off of the wire, increasing the receiver B1 field and the resulting signal. With different positioning of the return current path from the ground pad, we can also selectively increase the signal intensity at locations near the front of the guidewire.

                  1211.     MR-Assisted Retrograde Drilling of Osteochondral Lesions of the Talus - A Feasibility Study

Christian Seebauer1, Florian Wichlas1, Jens Rump1, Jens Pinkernelle1, Ioannis Papanikolaou1, Tobias Jung1, Sascha Chopra1, Ulf Teichgräber1, Hermann Josef Bail1

1Charité, Berlin, Germany

Osteochondrosis dissecans is a localized subchondral aseptic bone necrosis. However, its pathogenesis is still controversial. Various operative techniques for the treatment of osteochondral lesions of the talus with varying success have been reported. MRI yields additional information on the vitality and stability of the osteochondral fragment and allows differentiating the surrounding tissue, providing information on the fixation of the fragment. Here, we propose an innovative method for the retrograde drilling of necrotic areas in the talus using a MR-compatible drilling guide.

                  1212.     Novel Circumferential Immobilization of Breast Tissue Displacement During MR-Guided Procedures:
                                 Initial Results

Matthew Smith1, Xu Zhai1, Ray Harter2, Sean Fain1

1University of Wisconsin, Madison, Wisconsin, USA; 2Marvel Medtech LLC, Madison, Wisconsin, USA

The performance of image-guided devices for breast procedures is dependent on how well the tissue is stabilized during interventions. Novel MR-compatible devices for breast interventions have been previously developed by various groups using conventional 2D compression plates for breast tissue immobilization during a procedure. However, these devices typically distort the anatomy and cause discomfort for many women. We find that tissue is sufficiently immobilized during a trocar insertion with a 3D tissue immobilization concept using circumferential air bladders compared to an insertion without immobilization. Patient studies are planned to optimize the bladder shape and evaluate the required stabilization pressure.

                  1213.     An MR Compatible Tactile Sensor Array for Palpation-Based Diagnosis and Noise Analysis in MR

Zion Tsz Ho Tse1, Abbi Hamed1, Michael Lamperth1

1Imperial College London, London, UK

In this research piezoelectric sensors are utilized for force sensing and developed into an array for the purpose of inner-body palpation using an endoscope system. The sensors are shown to be MR compatible and highly sensitive and will output a charge signal on the slightest deformation (micron scale), however this property and their highly capacitive nature also entail that they are very sensitive to interference from the noisy scanner environment and hence significant attention must be paid into attenuating unwanted signals before they can present a serviceable transduction solution.

                   1214.     Navigation System for Interventional MR Image Guidance in a Closed-Bore Scanner: System Setup and
                                 Estimation of Targeting Accuracy
 [Not Available]

Harald Busse1, Robert Trampel1, 2, Wilfried Gründer3, Nikita Garnov3, Jochen Fuchs1, Tim-Ole Petersen1, Thomas Kahn1, Michael Moche1

1Leipzig University Hospital, Leipzig, Germany; 2Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; 3Leipzig University, Leipzig, Germany

The ongoing development of powerful MR imaging techniques also allows for advanced possibilities to guide and control minimally invasive interventions. Various navigation concepts have already been described for practically all regions of the body. Most diagnostic scanners, however, do not allow the physician to guide the instrument inside the magnet and, consequently, the patient needs to be moved out of the bore. The purpose of this work was to present a concept for real-time navigation with automatic patient registration and interventional control for a closed-bore scanner and to provide first estimates on the overall targeting accuracy in an experimental setup.

                  1215.     3D Real-Time Tracking Using Passive Fiducial Markers and Image Processing

Marc A. Rea1, 2, H Elhawary2, Zion T. Tse2, Donald W. McRobbie, 12, Michael Lamperth2, Ian Young2

1Charing Cross Hospital, London, UK; 2Imperial College London, London, UK

This abstract reports the implementation of an imaging methodology enabling real-time 3-dimensional tracking of devices using only passive micro-coil fiducials and image processing. A modified FLASH sequnce was executed with a minimum update rate of 1.8 seconds, sufficient for tracking movements up to 7mm/s. Using a MRI-compatible manipulator, prostate phantom lesions were successfully targeted with a maximum accuracy of 0.5mm.

                  1216.     Imaging-Guided Percutaneous Punctures Using a Combined MR Imaging / C-Arm CT Approach: A Pilot
                                Study Assessing the Feasibility

Bernhard C. Meyer1, Alexander B. Brost2, Liron Yatziv3, Norbert Strobel4, Wesley Gilson5, Karl Juergen Wolf1, Jonathan S. Lewin6, Frank K. Wacker, 16

1Charite - Universitätsmedizin Berlin, Berlin, Germany; 2Universität Erlangen, Erlangen, Germany; 3Siemens Corporate Research, Princeton, New Jersey, USA; 4Siemens Medical Solutions, Forchheim, Germany; 5Siemens Corporate Research, Baltimore, Maryland, USA; 6Johns Hopkins University, Baltimore, Maryland, USA

Purpose: To test the use MR images augmented on C-arm CT images to guide needle punctures in phantoms. Method: 10 punctures with 6 mm radius ring targets and 2 punctures of 15-20 mm cysts were performed. MR based fluoroscopic guidance was used.Result: The needle tip was correctly placed in 8/10 rings with a maximum distance to the center of 5mm. The cyst punctures were successful with a needle deviation of 10 and 8 mm.Conclusion: The combination of preacquired MR images, C-arm CT and fluoroscopy allows puncture of lesions not visible with fluoroscopy and hardly accessible using MR.

                  1217.     Advanced Communication Device for Interventional MR Communication and Talking

Margarita Con Lima1, James Bean, Thomas Collins

1Lima Institute for Advanced Studies, Lima, Peru

An advanced, MR compatible communication device for interventional MR is presented.  It is made of space age polymers and fibers, and can transmit audio data up to three meters with only 98% losses.


B1 Mapping & Correction

Hall D                                   Thursday 13:30-15:30

                  1244.     Radiofrequency (B1) Field Mapping in the Heart and Lungs Using a HASTE Double Angle Method

Kelvin Chow1, Ian Paterson1, Richard Thompson1

1University of Alberta, Edmonton, Canada

The double angle method for mapping radiofrequency (B1) fields was adapted for use in the heart and lungs using the HASTE pulse sequence and free breathing acquisition.  At 1.5T, significant heterogeneity was found within the chest, with flip angle variations >20  between the right and left heart, as well as ~10  between the base and apex.  The right lung experiences an average flip angle ~20  less than the left lung, with the largest spatial gradients around the heart.  The HASTE approach to mapping B1 fields is applicable to other regions and higher field strengths (with minor modifications).

                  1245.     Adiabatic B1 Mapping for RF Current Density Imaging

Kim Shultz1, Greig Scott1, John Pauly1

1Stanford University, Stanford, California , USA

RF current density imaging, useful for ablation treatment planning and RF safety evaluation, requires mapping a large range of B1 magnitudes in the presence of strong off-resonance effects. Standard B1 mapping methods like the double angle method require many repetitions to achieve the necessary dynamic range and lose accuracy in B1 phase measurement as off-resonance effects increase. An adiabatic excitation that is not brought fully to on-resonance creates transverse magnetization approximately linearly dependent on B1 magnitude over a large range of B1 values. Off-resonance effects can be corrected using a second excitation with a negative frequency offset. 

                  1246.     B1 Correction Using Double Angle Look-Locker (DALL)

Trevor Wade1, 2, Brian Rutt1

1Robarts Research Institute, London, Canada; 2University of Western Ontario, London, Canada

A new method for B1 mapping is introduced that takes advantage of fast 3D imaging at low flip angles.  By sampling the inversion recovery curve using two different, small tip angle RF pulses, an expression is obtained for both a corrected T1 and the achieved flip angle. This results in a B1 mapping technique that is very fast and efficient at low flip angles and does not require long TR values.

                  1247.     B1 Mapping of Coil Arrays for Parallel Transmission

Hans-Peter Fautz1, Mika Vogel1, Patrick Gross1, Adam Kerr2, Yudong Zhu3

1GE Global Research, Garching, Germany; 2Stanford University, Stanford, California , USA; 3GE Global Research, Niskayuna, New York, USA

A composite technique for B1 mapping of transmit coil arrays is proposed that uses all coil elements for signal excitation whereas the flip angle produced by the individual coils is encoded using a magnetization preparation. Only one flip angle encoding scan is required per coil element plus one reference scan that is used for the calibration of all coils. The dynamic range of the excitation pulse of the imaging part is reduced over the FOV allowing a significant increase in precision with which low B1 field amplitudes from single coils can be determined.

                  1248.     Simultaneous Measurement of B0- And B1-Maps with Modified Actual Flip Angle Imaging Sequence

Alexis Amadon1, Nicolas Boulant2

1CEA-Saclay, Gif-sur-Yvette, France; 2Siemens Medical Solutions, Saint-Denis, France

In high-field MRI, more and more sequences make use of the prior knowledge of B0- and B1-maps of the object under study. This abstract describes a fast method to simultaneously measure 3D maps of the B0 and B1 fields. Examples of brain maps acquired with this method are given at 3T.

                  1249.     Rapid Proton Density Weighted Abdominal MRI at 3 Tesla with RF Non-Uniformity Correction

Houchun Harry Hu1, Kyunghyun Sung1, Krishna S. Nayak1

1University of Southern California, Los Angeles, California , USA

A retrospective approach to compensate variations in signal intensity due to RF transmit and receive inhomogeneity is described for proton-density-weighted abdominal imaging.  The model utilizes rapid, low-resolution acquisitions to measure the RF transmit and receive fields.  Corrections for RF-induced signal shading are not only helpful in improving image quality, but are essential in applications requiring signal-intensity-based quantification.  We hypothesize that this method can accurately remove signal intensity non-uniformity typically encountered in multi-coil abdominal imaging, and demonstrate its performance at 3 Tesla.  Signal non-uniformity was reduced from 46% to 4% and 25% to 15% in phantom and in vivo experiments, respectively.


RF Pulse Design

Hall D                                   Thursday 13:30-15:30 

                  1320.     Improved Half RF Slice Selectivity in Presence of Eddy Currents with Quadratic Phase Saturation

Sonal Josan1, 2, Elena Kaye2, John Pauly1, Bruce Daniel2, Kim Butts Pauly2

1Stanford University, Stanford, California , USA; 2Stanford University, USA

Half RF excitation pulses used in ultrashort T2 imaging are very sensitive to eddy currents which distort its slice profile. The purpose of this work is to improve slice selectivity of the half RF in the presence of eddy currents, by using quadratic phase RF saturation to suppress any out of slice magnetization, thus providing a simple robust method for accurate T2* quantitation.

                  1321.     Fast Fat Suppression RF Pulse with Insensitivity to B1 Inhomogeneity: H-Sinc

Takayuki Abe1, Takeuchi Hiroyuki1, Takahashi Tetsuhiko1

1Hitachi Medical Corporation, Kashiwa, Japan

Robust fatsat is important in clinical applications. With 1.5-T or higher MRI scanners, an adiabatic inversion pulse is used for reducing the residual fat shown on an image caused by B1 inhomogeneity. Since this pulse is a 180‹-one, a long TI is required resulting in a dead time of the measurement. So, we developed a new fast fatsat pulse called H-Sinc, which excites at a flip angle near 90‹ and is insensitive to B1 inhomogeneity. Because H-Sinc can easily induce an arbitrary FA and does not require TI, it shows faster fat suppression than that of the adiabatic inversion pulse.

                  1322.     Improved Slice Profiles Using Low-Ripple Numerically Optimized SINC Pulses

Randy Lee Tyson1, Jonathan Sharp1, Boguslaw Tomanek1

1National Research Council of Canada, Calgary, Canada

Low-ripple RF pulse design through numerical optimization using the coefficients of the discrete cosine or Fourier transform of the SINC waveform as initial parameters. Bloch simulation and optimization of waveform parameters fitted to a target slice profile results in decreased rippling in both the pass and stopbands.

                  1323.     SLR RF Pulse Design for Arbitrarily-Shaped Excitation Profiles

Joëlle Karine Barral1, John Mark Pauly1, Dwight George Nishimura1

1Stanford University, Stanford, California , USA

The Shinnar-Le Roux algorithm has been widely used to reduce the pulse design problem to a well-known finite impulse response digital filter design problem when a rectangular slice profile is desired. However, there is no intrinsic limitation to such a profile. An adaptation of the SLR algorithm is proposed, which allows the design of large flip-angle pulses producing arbitrarily-shaped excited slice profiles accurate in both, magnitude and phase. This design should benefit alternative schemes like wavelet encoding which so far suffer from magnitude and phase distortions of the excited magnetization profiles, especially when SNR-efficient large flip-angles are desired.

                  1324.     Selective Adiabatic Refocusing Pulse Train for Nonlinear Phase Dispersion and Flip Angle Error

Ziqi Sun1, Jay L. Zweier1

1The Ohio State University, Columbus, USA

A selective adiabatic full passage (AFP) pulse train, consisted of two 90 degree hyperbolic secant (HS1_R20) pulses of alternate frequency sweep (AFS) at the two ends of the pulse train, and two low power HS1_R20 AFP pulses in the middle, was developed for spin refocusing in a 3D spin echo sequence. In comparison to an amplitude-modulated refocusing pulse, AFP-AFS pulse train substantially improved signal sensitivity and uniformity, which is ascribed to the effective compensation of the nonlinear phase dispersion and flip-angle errors associated with selective AFP pulses. This interpretation is supported by the theoretical analysis and Bloch equation simulation results.

                  1325.     Calibration Procedure of 2D RF Excitation Pulses Using Echo-Planar K-Space Trajectories

Carsten Warmuth1, Robert Krieg1

1Siemens Medical Solutions, Erlangen, Germany

A temporal mismatch between gradient and RF waveforms causes strong N/2 ghosting in two-dimensional excitations when using echo-planar k-space trajectories. We implemented a quick delay calibration approach preceding each sequence using 2D RF respiratory navigators.

                  1326.     2D-Selective RF Excitations Based on the PROPELLER Trajectory

Martin G. Busch1, 2, Jürgen Finsterbusch1, 2

1University Medical Center Hamburg-Eppendorf, Hamburg, Germany; 2Neuroimage Nord, Hamburg-Kiel-Lübeck, Germany

This work presents 2D-selective RF excitations based on the PROPELLER trajectory. The trajectory consists of segments of parallel lines which are rotated to one another. The center of k-space is covered by all segments which yields large flip angles for all segments. Profile blurring in the presence of off-resonance effects like chemical shift or magnetic field inhomogeneities is avoided by using non-selective refocusing RF pulses between the individual lines of each segment.

                  1327.     A New Method for Single-Shot 2-D OVS

Nathaniel James Powell1, Malgorzata Marjanska1, Julien Valette2, Pierre-Gilles Henry1, Michael Garwood1

1University of Minnesota, Minneapolis, USA; 2CEA-neurospin, Gif-sur-Yvette, France

Outer Volume Suppression (OVS) is sometimes needed in MR imaging and, more often, in spectroscopy.  MR Spectroscopic Imaging (MRSI) studies of the brain and other anatomical regions generally require some form of OVS to ensure that the strong lipid signals from the layer of skin and subcutaneous fat do not interfere with the desired signals from deeper tissues of interest.  Typically when OVS is used in brain MRSI, the standard approach involves sequentially applying multiple slice-selective (1D) suppression pulses at different angles around the periphery of the object, an approach that has drawbacks in terms of efficiency and Specific Absorption Rate (SAR).  Our method employs a single two-dimensional pulse to suppress an elliptically shaped annulus in one shot, saving both time and SAR, and in some cases providing a suppression pattern that more closely matches the anatomy.


SSFP Methods

Hall D                                   Thursday 13:30-15:30 

                  1357.     Partially Dephased SSFP for Elimination of Dark Bands

Brian A. Hargreaves1

1Stanford University, Stanford, California , USA

Balanced SSFP imaging sequences provide high signal-to-noise, rapid imaging, and diagnostically useful contrast, but their clinical utility is limited primarily by the dark-band artifacts resulting from off-resonance effects, especially at 3.0T.  This work demonstrates that using an unbalanced gradient immediately before and after the readout, combined with a modified reconstruction, a signal with balanced SSFP characteristics and no dark band artifacts can be obtained.  The technique is demonstrated in phantoms and human scans.

                  1358.     A Simplified Model for Stabilizing Alternating TR SSFP Sequences

Hsu-Lei Lee1, Krishna S. Nayak1

1University of Southern Califonia, Los Angeles, California , USA

An efficient initial preparation is critical for reducing the transient signal fluctuation in non-continuous steady-state imaging.  For conventional SSFP, LeRoux derived a Fourier relation between RF amplitude increments and the resulted oscillatory residues. In alternating TR SSFP the Fourier relation is also altered and the preparation scheme has to be modified. We utilized the SU2 formalism to build a simplified model for alternating TR SSFP sequences and present a design method that can be applied to arbitrary repetition times and RF phase cycling combinations. This approach is used to design stabilizer sequences for ATR-SSFP and wideband SSFP.

                  1359.     On the Spoiler Gradient in RF-Spoiled Gradient Echo Sequences  [Not Available]

Jochen Leupold1, Jürgen Hennig1, Klaus Scheffler2

1University Hospital Freiburg, Dept. of Diagnostic Radiology, Medical Physics, Freiburg, Germany; 2MR Physics, Department of Medical Radiology, University Hospital of Basel, Basel, Switzerland

RF-spoiled gradient echo sequences are widely used in clinical MRI. However, the theoretical description of the measured signal is not trivial, as a pseudo steady state of the voxel magnetisation is built up. We demonstrate that the well known occasional occurrence of ghost artifacts is a direct consequence of the existence of the PSS, and that there is no rigid rule for the needed moment of the spoiler gradient of an RF spoiled gradient echo sequence.

                  1360.     Banding Reduction in SSFP Imaging Through Accurate, Image-Based Estimation of the SSFP Sensitivities

Tolga Çukur1, Michael Lustig1, Dwight Georger Nishimura1

1Stanford University, Stanford, California , USA

Balanced steady-state free precession (SSFP) imaging offers high SNR efficiency within short scan times, but suffers from banding artifacts in the presence of strong field inhomogeneities. A common approach is to combine multiple SSFP images with different phase-cycling schemes. There is an inherent trade-off between SNR and the level of banding artifact reduction for most combination methods. In this work, accurate estimates of the SSFP sensitivities are obtained from multiple phase-cycled acquisitions using the magnitude-weighted complex-sum combination as an initial reference. Banding-free images with true SSFP contrast are reconstructed without sacrificing SNR performance.

                  1361.     Synthesis of Multiple Phase Cycled SSFP Images to Remove Band Artifacts as Well as to Improve
                                 the SNR   by Use of a Spectral Decomposition

Kwan-Jin Jung1, 2

1Univ. of Pittsburgh & Carnegie Mellon Univ., Pittsburgh, Pennsylvania, USA; 2University of Pittsburgh, Pittsburgh, Pennsylvania, USA

The band artifacts in SSFP can be removed by MIP of the multiple acquisitions of the phase cycled SSFP images. MIP, however,  cannot take the effect of averaging of the multiple images to improve the SNR. There were two reported methods, i.e., the complex sum and the squared sum, that had claimed to achieve both objectives. These two methods, however, could not be confirmed to achieve the major objective of the band artifacts removal. A new method to achieve both effects has been developed by use of the spectral decomposition of each phase cycled image into the low and high frequency components. The low frequency components are processed by MIP, while the high frequency components are averaged. The MIP of the low frequency components and the average of the high frequency components are summed, and results in the synthesized image that is free from the band artifacts with the improved SNR.


New Methods for Generating Contrast

Hall D                                   Thursday 13:30-15:30

                  1389.     Fast Low-Angle Positive-Contrast Imaging with Alternating Repetition Time SSFP

Tolga Çukur1, William Overall1, Dwight Georger Nishimura1

1Stanford University, Stanford, California , USA

Methods for generating positive-contrast images from susceptibility-induced magnetic field variations are useful for applications such as the guiding of interventional devices or imaging of super paramagnetic iron oxide (SPIO)-labeled cells. SSFP-based methods, such as fast low-angle positive-contrast SSFP (FLAPS), offer fast imaging and flow insensitivity. However, the level of background suppression can be limited. In this work, we employ the alternating repetition time (ATR) SSFP stop-band to suppress the signal from on-resonant spins. The ATR sequence provides positive contrast with robust suppression for a wide range of flip angles and tissue parameters.

                  1390.     Short T2 Positive Contrast Imaging with Self-Refocused Spiral Pulse Sequence

Angus Zoen Lau1, Charles Henry Cunningham1

1Department of Medical Biophysics, University of Toronto, Toronto, Canada

Conventional imaging of superparamagnetic iron oxide (SPIO) particles yields negative contrast in the region surrounding the particles. Recent positive contrast techniques refocus this dephased signal using an off-resonance spin echo sequence. We investigate the possibility of imaging off-resonance short T2 spins using a short TE spiral pulse sequence containing a spectrally-selective self-refocusing RF pulse. A short T2 agar gel model using gadolinium as the field perturber is used to evaluate the performance of this sequence. We demonstrate that the short TE sequence is able to refocus increased signal from off-resonance short T2 spins compared to a spectrally-selective spin echo sequence.

                  1391.     Faster Myelin Imaging in Vivo; Validation of 3D Multi-Echo T2-Relaxation Measurements

Shannon Heather Kolind1, Burkhard Mädler2, Alex Lloyd MacKay1

1University of British Columbia, Vancouver, Canada; 2Philips Medical Systems,, Vancouver, Canada

We compared results from a recently introduced 3D multi-echo T2-relaxation imaging technique to the standard single-slice multi-echo T2-relaxation measurement most common in the literature. For 10 healthy controls, myelin water fraction correlated strongly between the techniques (slope=1.00,intercept=-0.91%,R2=0.89,p<0.0001) with significant differences only occurring in peripheral brain. Geometric mean T2 was not significantly different in any brain structure examined except minor forceps. SNR was generally higher using the 3D technique. In conclusion, results from the 3D multi-echo T2-relaxation technique were generally consistent with single-slice results, and achieved 7 times greater brain coverage in similar scan times with higher SNR.

                  1392.     Voxel-Based Morphometry at 3 Tesla: Which T1-Weighted Sequence is Best?

Christine Lucas Tardif1, D Louis Collins1, G Bruce Pike1

1Montreal Neurological Institute, Montreal, Canada

The stability and accuracy of the voxel-based morphometry (VBM) process is crucial in large studies to improve the power of statistical results and minimize regional bias. In this study, we evaluated three protocols, FLASH, MP-RAGE and MDEFT, from the perspective of VBM. Nine volunteers were scanned twice for each protocol. We performed a VBM analysis of grey matter (GM) density between the sequences, as well as GM density scan-rescan variability. The results show large areas of significant difference in GM density and variability between the three protocols, and suggest that MDEFT is best suited to this type of analysis.

                  1393.     MP2RAGE, a Self-Bias Field Corrected Sequence for Improved Segmentation at High Field

José P. Marques1, 2, Tobias Kober1, 3, Wietske van der Zwaag1, 2, Gunnar Kruegger1, 3, Rolf Gruetter1, 4

1Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland; 2University of Lausanne, Lausanne, Switzerland; 3Siemens Medical Solutions-CIBM, Lausanne, Switzerland; 4University of Lausanne and Geneva, Switzerland

To improve bias field correction as well as contrast between tissues with different T1’s, the MPRAGE sequence was modified into a MP2RAGE (Magnetization Prepared with 2 RApid Gradient Echoes), which accommodates two gradient echo modules after each inversion, GRETI1 and GRETI2, which are characterized by their two different inversion times (TI1 and TI2) and flip angles α 1 and  α 2). The use of the combined images resulted in higher contrast between CSF, GM and WM.

                  1394.     Acceleration of Multi-Echo Spin-Echo Imaging for T2 Mapping Using Single or Multiple Coils

Julien Sénégas1, Wei Liu2, 3, Hannes Dahnke1

1Philips Research Europe, Hamburg, Germany; 2National Institutes of Health, Bethesda, USA; 3Philips Research North America, Briarcliff Manor, USA

This work presents a new acceleration method that exploits the temporal correlation of the k-space signal at different echo times to reduce the number of phase-encoding steps in a multi-echo spin-echo sequence. The extension to the case of multiple coils is addressed. The approach is evaluated with respect to SNR and reconstruction artefacts, and compared to SENSE and GRAPPA. For single coil acquisitions, the proposed method represents a new way of reducing the scan time that was not accessible with sensitivity encoding approaches. For multiple coils acquisitions, it extends the existing methods and allows an appreciable improvement in reconstruction quality, limiting especially noise amplification.

                  1395.     "High-Frequency Relaxation" with Contrast Agents

Christian Hoehl1, Nouri Elmiladi1, Jessica Mende1, Karl Maier1

1Rheinische Friedrich-Wilhelms-Universität, Bonn, Germany

A new method of contrast may be achieved by using different nanoparticles as high frequency transmitters. Activated by ultrasound radiation, the nanoparticles emit electromagnetic waves within their nearest neighborhood. This produces a change in the relaxation rate, depending on the ultrasound parameters and the physical properties of the tissue.

                  1396.     An Optimal Pulse Sequence for Parahydrogen-Induced Polarization of Heteronuclei

Stephen Kadlecek1, Vahid Vadhat1, Kiarash Emami1, Richard A. Guyer1, Robert V. Cadman1, Jiangsheng Yu1, John MacDuffie Woodburn1, Masaru Ishii, 12, Hans Hyonchang Kim1, Warren Gefter1, Rahim R. Rizi1

1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Johns Hopkins University, Baltimore, Maryland, USA

We present a closed-form prescription for NMR pulses and delays which maximizes heteronuclear hyperpolarization through transfer of spin order from a coupled nuclear singlet state.  This result is applicable to the preparation of MRI contrast agents through the method of Parahydrogen-Induced Polarization.  The sequence is derived using a geometric analogy to the evolution of orthogonal density matrix components.  We find that the sequence is optimal in that it minimizes sequence duration, and therefore T2-like relaxation, and is less sensitive to pulse imperfections than other prescriptions studied.

                  1397.     Triggered Angiography Non-Contrast Enhanced (TRANCE) of Peripheral Arteries: Optimization of
                                 Systolic and Diastolic Time Delays for Electrocardiographic Triggering

Andreas Stadlbauer1, Wilma van der Riet2, Markus Scheidegger3, Stephan Gruber4, Erich Salomonowitz1

1Landesklinikum St.Poelten, St. Poelten, Austria; 2European MRI Consultancy (EMRIC), Strasbourg, France; 3Philips AG Medical Systems, Zurich, Switzerland; 4Medical University Vienna, Vienna, Austria

We determined the optimal systolic and diastolic time delays (TD) for ECG-triggering of a non-contrast enhanced MRA (TRANCE) in patients with peripheral arterial disease. We specified the requirements for the systolic images with minimal and the diastolic images with maximum arterial SNR. An ECG-triggered T2w TSE (VISTA) sequence was performed in 12 patients using variable trigger delays for systolic and diastolic phase. The SNR in the popliteal and anterior tibial arteries of systolic and diastolic images were determined. The optimal systolic TD was 14–21ms smaller, the optimal diastolic TD 200ms apart from time of maximum peak velocity.

                  1398.     Spectrally Selective Hard Pulses (SSHP) for Positive Contrast MRI: Theory and Validation

Twinkle Gupta1, Saurabh Shah2, Sumeet Virmani, Reed Omary1, Andrew Larson1

1Northwestern University, Chicago, Illinois, USA; 2Siemens Medical Solutions, Chicago, Illinois, USA

We investigated the use of spectrally selective hard pulses (SSHP) for positive contrast MRI of paramagnetic markers. Our primary focus was to study the effects of specific SSHP-parameters (targeted off-resonance and no. of binomial sub-pulses=N) upon marker conspicuity, background and fat suppression. Studies were performed using simulations and phantom models. Background suppression increased with increasing N and targeted off-resonance. Marker conspicuity was higher at lower N and off-resonance values. Fat suppression maximized at 100Hz off-resonance. SSHP pulses offer a promising method for positive contrast MR. Further developments are needed to demonstrate the utility of this technique for in-vivo clinical applications.

                  1399.     A Novel FLAIR PROPELLER Technique for T1-Weighted Brain Imaging

Zhiqiang Li1, Donglai Huo2, Eric Aboussouan2, Xiaoli Zhao3, John Karis2, Leland Hu2, Zhu Li3, James G. Pipe2

1GE Healthcare, Phoenix, Arizona , USA; 2Barrow Neurological Institute, Phoenix, Arizona , USA; 3GE Healthcare, Waukesha, Wisconsin, USA

Spin Echo (SE) sequence is widely used for T1-weighted brain imaging. T1 FLAIR FSE also has drawn significant attention recently due to superior SNR and CNR, and improved lesion conspicuity. However, these techniques are significantly impaired in regions affected by flow artifact, which is even worse in post-contrast imaging. Turboprop is a technique insensitive to flow artifact. In this work, we combine FLAIR preparation with turboprop to produce superior T1 contrast with minimized flow artifact. This technique can be used for both pre- and post-contrast T1 imaging, and has several advantages over current clinical T1 SE protocols.

                  1400.     T1 Mapping of MT Effects in BSSFP  [Not Available]

Rexford David Newbould1, Marcus T. Alley1, Stefan Ropele2, Roland Bammer1

1Stanford University, Stanford, California , USA; 2Medical University Graz, Graz, Austria

Recent work has presented the concept of magnetization transfer effects in balanced SSFP (bSSFP) acquisitions for calculating MTR maps from variation in the steady-state magnetization. Another quantity of interest is the variation in T1 of the free pool under varying saturation of the bound pool. By prefacing the bSSFP train with an inversion pulse, the transient magnetization progresses towards steady-state with an apparent rate constant known as T1*, which can be related to underlying T1.  In this work IR-bSSFP relaxometry is performed with varying direct RF power deposition, which can measure both the variation in steady-state levels and underlying T1.

                  1401.     Magnetization Transfer Effects in Cardiac Balanced SSFP Imaging at 3T

Kyunghyun Sung1, Hsu-Lei Lee1, Houchun Harry Hu1, Krishna S. Nayak1

1University of Southern California, Los Angeles, California , USA

Magnetization transfer (MT) in 3T cardiac balanced steady state free precession (bSSFP) imaging can possibly produce a new type of contrast to detect infarcts and inflammation of the myocardial tissue. We evaluate the range of MT ratio (MTR) with different RF pulse elongations by a constant TR (3.6ms – 5.6ms). We also perform multiple measurements to establish variation range in 3T cardiac imaging. The study shows a MTR of 12 – 19% in 3T bSSFP cardiac imaging while a MTR of 30 – 50% has been reported in brain applications.

                  1402.     Integration of Magnetization Preparation Sequences Into SSFP Sequences: A Fat Saturation Example

Sergio Andres Uribe1, Reza Razavi1, Tobias Schaeffter1

1Kings College London, London, UK

In this work we present a new method that allows the integration of magnetization preparation sequences into b-SSFP sequence without disturbing the steady state. Gradients and rf pulses are integrating into steady state free precession sequence after certain time interval without the need to stop and re-establish the steady state. An example for fat suppression has been implemented and tested in phantom and volunteers. Other preparation techniques can also benefit from this method, such as regional saturation (REST) or spin labeling.

                  1403.     Dual Acquisition Phase Difference SSFP for Improved Fat Suppression

Catherine Judith Moran1, Walter F. Block2

1University of Wisconsin, Madsion, USA; 2University of Wisconsin, Madison, USA

Linear Combination SSFP is one of a number of methods that provide fat-water separation in balanced SSFP.  Fat/water separation in this dual pass method suffers when the magnitude of the signal varies between passes.  Instead, we recognize the phase difference between the two passes robustly falls into two categories, 0 for water and 180 degrees for fat.  Unlike previous phase-sensitive methods, common mode sources of phase error cancel out. Thus an extremely simple reconstruction method can classify fat voxels and remove them.  We demonstrate the method in dramatic improvements of contrast in breast and knee imaging.

                  1404.     Balanced Steady-State Free Precession Spatial Gridding

Walter Robert Thurmond Witschey II1, Mark A. Elliott, Jeremy Magland1, Ravinder Reddy

1University of Pennsylvania, Philadelphia, USA

Steady-state free precession gridding exploits the external field sensitivity of the balanced gradient echo sequence to generate a uniform image grid. A simple gradient pulse added to the balanced gradient echo sequence 'unbalances' the sequence and generates a grid with spacing proportional to the gradient pulse amplitude and gradient. Potential applications include steady-state diffusion weighting and persistent motion sensitivity.

                  1405.     Simultaneous T1 and T2* Mapping Without B1 Correction

Philipp Mörchel1, Gerd Melkus1, Markus Kotas1, Michael Flentje1, Peter Michael Jakob1

1University of Würzburg, Würzburg, Germany

A new method for the simultaneous measurement of T1 and T2* maps is presented. This method is robust against variations in flip angles due to B1 inhomogeneities of the resonator. Moreover, this sequence is time efficient because both parameters can be measured in the time the T1 measurement would take. Another advantage is that there no misregistration artifacts due to motion during a consecutive measurement of the single parameters T1 and T2*.

                  1406.     TRITONE: RF Insensitive T1 Estimator Using SPGR Acquisitions

Roman Fleysher1, Lazar Fleysher1, Songtao Liu1, Oded Gonen1

1NYU School of Medicine, New York, USA

We present a method of T1 estimation designed to be free of systematic errors caused by B1 inhomogeneity in which the value of T1 is extracted from three 3D spoiled-gradient-recalled-echo (SPGR) images acquired with EPI readout. The method provides protocols optimized for precision in T1 given available scan time. The precision is comparable to that of the adopted two-SPGR method in the same time and spatial resolution. If the two-SPGR methods are combined with B1 measurement for accuracy, then TRITONE supersedes them in precision in the same total time.

                  1407.     Intermolecular Zero-Quantum Coherence Imaging in Structured Samples

Bernard Siow1, Li Sun1, Andrew M. Blamire1

1Newcastle University, Newcastle upon Tyne, UK

Intermolecular multiple quantum coherence imaging sequences have recently been shown to provide a fundamentally different contrast mechanism to conventional MRI. A numerical study of intermolecular zero-quantum coherence imaging has shown sensitivity to susceptibility gradients at selected distance scales. In this study, an iZQC sequence was implemented and iZQC signal verified. The sequence was used to investigate sensitivity to susceptibility gradients at selected distance scales in structured samples. Images show contrast in areas where susceptibility gradients are present. Furthermore, contrast was modulated by the distance scale selected. Further results suggest that contrast is modulated by specific resonant frequency difference at distance scale selected.

                  1408.     Measurement of T2* Relaxation Time of Cerebral White Matter Structures Using Large-Scale
                               Field Inhomogenetiy Correction Technique in Healthy Volunteers at 3T
 [Not Available]

Akira Sasao1, Mika Kitajima1, Toshinori Hirai1, Hirofumi Fukuoka1, Tomoko Okuda1, Tomoyuki Okuaki2, Shutaro Saiki2, Yasuyuki Yamashita1

1Kumamoto University, Kumamoto, Japan; 2Philips Medical Systems, Japan

We measured T2* values of the five white matter structures, the genu and splenium of the corpus callosum, posterior limb of the internal capsule (PLIC), occipital white matter adjacent to the lateral ventricle and frontal white matter, at 3T using a multi-echo fast field echo sequence with and without the main field inhomogeneity (B0 inhomogeneity) correction in 20 neurologically normal cases. The mean T2* values of all measured white matter regions using B0 inhomogeneity correction was statistically longer than those without B0 inhomogeneity correction. The mean T2* value of PLIC using B0inhomogeneity correction was longest among the five regions.


Compressed Sensing

Hall D                                   Thursday 13:30-15:30

                  1477.     Suppression of MRI Truncation Artifacts Using Total Variation Constrained Data Extrapolation

Kai Tobias Block1, Martin Uecker1, Jens Frahm1

1Biomedizinische NMR Forschungs GmbH, Goettingen, Germany

Finite sampling of k-space causes ringing artifacts from signal truncation at the border of the measured k-space. This work demonstrates that the simple assumption of a piecewise-constant object can be exploited to extrapolate the data in k-space beyond the measured part. The assumption translates into a total variation minimization problem which can be solved with a non-linear optimization algorithm and allows for a significant reduction of truncation artifacts without compromising resolution. In the presence of substantial noise, a modified approach offers edge-preserving denoising which, in addition to supplementing data, also tolerates slight deviations from the measured data.

                  1478.     Compressed Sensing Parallel Imaging

Chen Zhao1, Tao Lang1, Jim Ji1

1Texas A&M University, College Station, USA

Both parallel MR Imaging (pMRI) and compressed sensing (CS) can significantly reduce image acquisition time in MRI, the former by utilizing multi-channel receivers and the latter by utilizing the sparsity of MR images in a transformed domain. An integrated approach was developed to use CS as a regularization tool to improve the pMRI reconstruction. Reconstruction results from in-vivo data show that CS can significantly suppress the aliasing artifacts and improve SNR, but with very minor resolution loss. Comparison with the truncated SVD and the Tikhonov  regularization were presented.

                  1479.     Nonlinear Inversion with L1-Wavelet Regularization – Application to Autocalibrated Parallel Imaging

Martin Uecker1, Kai Tobias Block1, Jens Frahm1

1Biomedizinische NMR Forschungs GmbH am MPI für biophysikalische Chemie, Goettingen, Germany

Recent algorithms for autocalibrated parallel imaging estimate the coil sensitivities and the image at the same time. Regularization is commonly employed to counteract the low SNR due to the reconstruction process (quantified by the g-factor map). In contrast to linear reconstruction methods which are restricted to a regularization related to the L2-norm of the image, nonlinear regularization methods like the L1-norm in combination with a sparsity transform or total variation are known to suppress noise much more efficiently. This work demonstrates how L1-wavelet regularization can be incorporated into an autocalibrating parallel imaging algorithm based on a regularized nonlinear inversion method.

                  1480.     Applying Compressed Sensing in Parallel MRI

Bing Wu1, Rick P. Millane1, Richard Watts1, Philip Bones1

1University of Canterbury, Christchurch, New Zealand

Compressed sensing is used in recovering images from multiple receiver coil data sets, and the results are compared to those obtained from using a direct image recovery method (SENSE). It is shown that compressed sensing achieved better reconstruction results than the conventional SENSE approach at high acceleration factors, since the latter suffers badly from deteriorated SNR.

                  1481.     Accelerating Dynamic Contrast-Enhanced MRI Using Compressed Sensing

Tao Lang1, Jim Ji1

1Texas A&M University, College Station, USA

Compressed Sensing (CS) is an effective approach to fast imaging by utilizing the signal sparsity in a transformed domain. We developed a CS imaging method for dynamic contrast enhanced MRI. Specifically, a difference operator is applied to the successive temporal data frames to enhance the spatial signal sparsity for CS reconstruction. The new algorithm method is assessed using simulated and in-vivo dynamic imaging data. The result shows that the new method provides higher resolution than zero-padded Fourier reconstruction and the Keyhole method, and it results in reduced artifacts and noise than conventional CS reconstruction where no temporal information is used.

                  1482.     Interventional MRI with Sparse Sampling: An Application of Compressed Sensing

Diego Hernando1, Justin Haldar1, Leslie Ying2, Kevin King3, Dan Xu3, Zhi-Pei Liang1

1University of Illinois at Urbana-Champaign, Urbana, Illinois, USA; 2University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA; 3G.E. Medical Systems, Milwaukee, Wisconsin, USA

Interventional MRI (I-MRI) is an important dynamic imaging application, allowing the guidance of therapeutic procedures, which requires high frame-rate and near-real-time reconstruction. Compressed sensing (CS) allows high-resolution reconstruction from a reduced number of samples by exploiting the sparsity of the signal. In this work, CS is tailored to ¡ maximize¡± the sparsity in each frame while satisfying the inherent causality constraints in I-MRI reconstruction, so that high-quality images can be obtained from a small number of samples.

                  1483.     Prior Information Constraint Compressed Sensing (PICCS): A Novel Technique for MR Myocardial
                                Perfusion Imaging

Orhan Unal1, 2, Jie Tang1, Guang-Hong Chen1

1University of Wisconsin, Madison, Wisconsin, USA

Recently, a novel reconstruction technique called PICCS (Prior Information Constraint Compressed Sensing) has been developed. This technique enables accurate reconstruction of high SNR images with large undersampling factors (>50 in 2D). In this work, PICCS and its utility in MR perfusion imaging is investigated. In PICCS, the sparsity of the difference image between the target image and the high SNR prior image is exploited.  When this PICCS sparsity is combined with other known sparsifying transforms such as total variation (TV) norm used in compressed sensing (CS), PICCS enables accurate reconstruction of images using fewer projections than required by CS and standard filtered backprojection (FBP) reconstruction

                  1484.     MRI with Accelerated Multi-Coil Compressed Sensing

Luca Marinelli1, Christopher J. Hardy1, Daniel J. Blezek1, 2

1General Electric, Niskayuna, USA; 2Mayo Foundation and Clinic, Rochester, USA

Parallel imaging methods reduce acquisition time at the expense of aliasing artifacts and image SNR.  Compressed sensing has emerged as a framework for exact reconstruction for compressible signals and images. A novel approach is proposed to adapt distributed compressed sensing algorithms to accelerated multi-coil MR imaging. The algorithm employs coil sensitivity maps and can be combined with parallel imaging to achieve high acceleration factors. We demonstrate the convergence properties of the method on a numerical phantom and apply it to FGRE imaging.

                  1485.     Superresolution Parallel Magnetic Resonance Imaging

Ricardo Otazo1, Fa-Hsuan Lin2, Graham Wiggins2, Ramiro Jordan1, Stefan Posse1

1University of New Mexico, Albuquerque, New Mexico, USA; 2Massachusetts General Hospital, Boston, Massachusetts, USA

Parallel MRI reconstruction is formulated as a superresolution problem where acceleration is performed by acquiring the low spatial resolution representation of the object being imaged and coil sensitivity maps are acquired with higher target spatial resolution. The increase in spatial resolution will be determined by the degree of sensitivity variation within the low resolution voxel. The method is applicable to receiver arrays with a large number of small elements which provide strong spatial variation of the coil sensitivity maps. Superresolution Sensitivity-Encoding (SURE-SENSE) represents a powerful alternative to standard SENSE for the same acquisition time and it is advantageous for low spatial resolution where the aliasing from intra-voxel coil sensitivity variation is removed. We show feasibility of the method for human brain imaging using receiver arrays with 32 and 96 elements.

                  1486.     An Experimental Comparison of Super-Resolution Techniques in 2-D Multi-Slice MRI

Richard Z. Shilling1, Marijn E. Brummer2

1Georgia Insitute of Technology, Atlanta, Georgia, USA; 2Emory University, Atlanta, Georgia, USA

Most super-resolution reconstruction (SRR) techniques proposed for MRI to date have involved multiple multi-slice acquisitions with sub-pixel shifts in the slice-selection or phase-encoding direction.  Another SRR technique has been developed called “Multi-stack” (MS), which instead of using sets of parallel shifted scans (PS), uses multiple multi-slice stacks of the same object, scanned at different orientations, rotated about the frequency-encoding axis.  In this work we compare these methods with a real scanning experiment using 2-D Inversion Recovery acquisition.

                  1487.     Introduction of a Nonconvex Compressed Sensing Algorithm for MR Imaging

André Fischer1, 2, Felix Breuer2, Martin Blaimer2, Nicole Seiberlich1, Peter Michael Jakob1, 2

1University of Wuerzburg, Wuerzburg, Germany; 2Research Center for Magnetic Resonance Bavaria e.V., Wuerzburg, Germany

In recently published works, convex optimization procedures were chosen for recovering missing data with Compressed Sensing (CS). This method depends on a proper adjustment of parameters in the functional to be optimized; this is often computationally expensive and reduces the advantage of accelerated data acquisition. In this work, a CS reconstruction algorithm based on a nonconvex procedure is introduced for MR imaging. No parameter determination is necessary, thus reducing the computational load. A preliminary application in the field of MR is shown, as well as a demonstration which indicates that the nonconvex technique offers similar results as a convex optimization.

                  1488.     Combining Compressed Sensing and Parallel Imaging

Kevin F. King1

1GE Healthcare, Waukesha, Wisconsin, USA

Compressed sensing uses L1-norm minimization in a sparse transform space to reconstruct randomly undersampled k-space data.  Parallel imaging uses L2-norm error minimization to incorporate receive B1 information into the reconstruction of undersampled multicoil k-space data.  An L1-norm penalty function has also been used for denoising and regularization of parallel imaging and non-Cartesian k-space reconstructions.  These methods are overlapping and complimentary and can be combined by reconstructing randomly undersampled multicoil k-space data with both L1- and L2-norm minimization.  This combines compressed sensing and L1-regularized parallel imaging and denoises the image.  The resulting acceleration can be higher than with either technique alone.

                  1489.     Data Interpolation in Phase-Scrambling Fourier Transform Technique by Modified Gerchberg's
                                Algorithm for Alias-Free Image Reconstruction

Yoshifumi Yamada1, Satoshi Ito1

1Utsunomiya University, Utsunomiya, Japan

This report presents a novel data interpolation method in the phase-scrambling Fourier transform (PSFT) imaging technique. A coarsely sampled PSFT signal which an aliasing artifact is produced in the reconstructed image can be interpolated to obtain fully encoded signal by using an iteration method based on the Gerchberg's algorithm known as a super resolution technique. Modification of the Gerchberg's algorithm is made to apply the method to interpolation of PSFT signal. Numerical simulation using MR images shows that alias-free images are reconstructed from the interpolated PSFT signal by using this technique.


Tissue Segmentation & Localization

Hall D                                   Thursday 13:30-15:30

                  1531.     Analysis of Bilateral Asymmetries in Breast MR Images Based on Texture and Directional Statistics
                                of the Breast Parenchymal

Ricardo J. Ferrari1, Anne L. Martel1, 2

1Sunnybrook Health Sciences Centre, Toronto, Canada; 2University of Toronto, Toronto, Canada

The main objective of this work is to use bilateral asymmetry analysis to detect abnormal global changes in the breast parenchymal flow. The analysis, which is based on the differences in texture and directional edge information obtained from the left and right MR breast images, aims to help radiologists in the detection of breast cancer in women with a high risk of developing such disease. Preliminary results of the proposed method has shown an average accuracy of 75.0% on the classification when applied to 40 MRI cases (20 benign and 20 malignant).

                  1532.     Improved Vessel Segmentation Within Tumors Using Implicit Active Contours Driven by Local Binary
                                Fitting Energy

Chunming Li1, Zhaohua Ding1, Mary M. Zutter1, John C. Gore2, Thomas Yankeelov3

1Vanderbilt University, USA; 2Institute of Imaging Science, USA; 3Vanderbilt University, Nashville, USA

We apply our recently developed local binary fitting (LBF) method of image segmentation to the problem of separating angiogenic vessels amid a heterogeneous intensity background and show how it yields superior results than common methods of vessel segmentation which include simple intensity thresholding and the Chan-Vese model.  The LBF algorithm is less sensitive to noise than thresholding and Chan-Vese model, provides more accurate segmentation and can be applied to images with substantial intensity inhomogeneities.

                  1533.     Fast and Robust Brain-Tissue Segmentation

Suyash Prakash Awate1, James C. Gee1

1University of Pennsylvania, Philadelphia, USA

We present a novel, fast, and robust brain-tissue segmentation method.

                  1534.     Pinned Snakes: A Technique to Extract Mouse Brain Data from Whole Head MRI

Yutong Liu1, 2, Mariano Uberti1, Michael Boska1

1University of Nebraska Medical Center, Omaha, Nebraska, USA

We developed a technique to extract mouse brain from in vivo head MRI based on an active contour model (“snake”). Most brain extraction techniques developed for human head MRI that employ the image intensity and gradient cannot be directly used for mouse. We include higher level image constraints (“pins”) in the energy function of the snake. The definition of the pins and the initial snakes are automated in this technique. Results have demonstrated that pinned snakes can accurately extract the brain from 3D head MRI with minimal user intervention.

                  1535.     Optimized Filtering of ICA Corrected DCE-MRI Perfusion Images Using Tikhonov Regularization

Gernot Reishofer1, Stefan Ropele1, Franz Ebner, Rudolf Stollberger2

1Medical University Graz, Graz, Austria; 2Technical University Graz, Graz, Austria

Previous studies have shown the potential of independent component analysis to separate the signal assigned to macro vessels from tissue signal. This enables an algorithm for minimizing macro-vessel signal in DCE-MRI perfusion imaging to avoid overestimation of relative blood flow and blood volume. The reconstruction step for restoring corrected DCE-MRI time series involves the solution of ill-posed linear systems. Direct back transformation leads to noise amplification in the reconstructed dynamic time series which results in noisy hemodynamic parameter maps. We found that Tikhonov regularization improves the visualization of hemodynamic parameter changes without affecting the quality of macro-vessel minimization through ICA

                  1536.     Kidney Segmentation in 4D DCE-MRI Renal Studies: A Physiological Approach

Voreak Suybeng1, Borys Shuter1, David Stringer2, Ashraf Kassim1, Shih-Chang Wang1

1National University of Singapore, Singapore, Singapore; 2National University Hospital, Singapore, Singapore

4D DCE-MRI studies contain temporal information which may be useful in segmenting the kidney, liver and spleen. Three cluster analysis techniques (Kohonen Neural Network, Fuzzy K-Means, Expectation-Maximization) and Factor Analysis of Dynamic Structures (FADS) are compared. All performed similarly in segmenting kidney parenchyma from other abdominal organs. FADS appeared to be most sensitive to the temporal information producing TICs for kidney compartments that were of more physiological interest.

                  1537.     Vein Classification Using Vesselness Filters on SWI Data Acquired at 3T and 7T

Peter Jan Koopmans1, Rashindra Manniesing2, Wiro J. Niessen2, Max A. Viergever3, Markus Barth4, 5

1F.C. Donders Centre for Cognitive Neuroimaging, Radboud University, Nijmegen, Netherlands; 2Department of Medical Informatics and Radiology, Rotterdam, Netherlands; 3Image Sciences Institute, University Medical Center Utrecht, Netherlands; 4F.C. Donders Centre for Cognitive Neuroimaging, Radboud University, Nijmegen, Netherlands; 5Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Germany

MR venography data of the brain were acquired at 3T and 7T using susceptibility weighted imaging (SWI). Two automated vein segmentation filters, the Utrecht vesselness filter and Vessel Enhancing Diffusion (VED), were tested. VED results were in excellent agreement with manual segmentation. Results at 3T were marginally better than those at 7T due to increased inhomogeneity at the latter field strength. However, the acquisition time at 3T was 50% longer. SWI at 7T shows good promise for future MR venography.

                  1538.     Partial Volume Segmentation Using Super-Resolution, Structure Maps and Multi-Scale Processing

James P. Withers1, Mark E. Bastin1, Amos J. Storkey1

1University of Edinburgh, Edinburgh, UK

The segmentation of brain MRI volumes is complicated by noise as well as partial volume voxels that contain a mixture of tissue types. Automated algorithms that perform partial volume segmentation often rely on average tissue class maps that may not represent the target anatomy, especially blood vessels and cortical sulci. These small structures can also be smoothed out by aggressive homogeneity constraints or confined to tissue boundaries only. In this abstract, robust techniques for minimizing aliasing through super-resolution, quantifying mixtures over a small number of discrete mixture states, and detecting tube-like structures using differential geometry are examined.

                  1539.     Lesions Detection on 3D Brain MRI Based on Robust Hidden Markov Chain

Stephanie Bricq1, 2, Christophe Collet1, Jean-Paul Armspach2

1LSIIT - UMR CNRS 7005, Illkirch, France; 2LINC - UMR CNRS 7191, Strasbourg, France

We present a new automatic robust method to estimate parameters to segment brain MR images  (WM, GM, CSF) and MS lesions using the Hidden Markov Chain (HMC) model. For this aim, we use the Trimmed Likelihood Estimator (TLE) to extract outliers and propose to include a priori information brought by a probabilistic atlas. Tests on Brainweb images with MS lesions have been carried out.

                  1540.     Automated Lesion Discrimination and Outlining

David Scott Wack1, 2, Michael Dwyer1, Sara Hussein1, Christopher Caiola1, Peter Hojczyk1, Robert Zivadinov1

1State University of New York at Buffalo, Buffalo, USA

A method which uses Stochastic Discrimination for the detection of MS lesions was trained using 40 scans from MS subjects acquired from 4 scanners.  Thirty-nine scans  were used as a test set.  The pattern recognition results were subsequently used in a stage which created an outline of the lesions in a format accepted by JIM (Java Image Manipulation) software, allowing for further editing of the results.  A comparison of the un-edited ROIs and expert drawn ROIs had median Kappa value of .61.  ROIs from either method predicted over 93% of the lesions found in the other.

                  1541.     Increasing the Sensitivity of Detection of Targeted MRI Contrast Agents Using Bayesian Image
                                Analysis Methods

Holly C. Canuto1, 2, Marko Velic3, Charles I. McLachlan3, Mikko I. Kettunen1, 2, Anant S. Krishnan1, Andre' A. Neves1, 2, Maaike M. de Backer1, De-en Hu1, Michael P. Hobson1, 3, Kevin M. Brindle1, 2

1University of Cambridge, Cambridge, UK; 2Cancer Research UK, Cambridge, UK; 3Metropolis Data Consultants, Cambridge, UK

The capability to perform reliable and accurate automated segmentation of MR images does not currently exist within the MR imaging community. Bayesian image analysis methods have been used successfully in the astronomy community for more than thirty years to de-noise images and enhance feature recognition.  We have developed a Bayesian Multi-Region Segmenter (BMRS) to provide reliable assessment of contrast heterogeneity within murine lymphomas and potentially enhance the sensitivity of contrast agent detection.

                  1542.     Gradient-Field-Based MRI Knee Cartilage Segmentation Algorithm with Self Correction

Ana Rodriguez-Soto1, 2, Julio Carballido-Gamio2, Thomas M. Link2, Sharmila Majumdar2

1Universidad Iberoamericana, Mexico City, Mexico; 2University of California, San Francisco, San Francisco, California , USA

In this work a semi-automatic cartilage segmentation technique is presented. The bone cartilage interface was extracted by Canny edge detection and was used as initialization for the segmentation of the articular surface. First and second order gradients of pixel intensities were used to move the control points of the splines representing the cartilage contours. A self correction technique based on local cartilage thickness values of adjacent slices was implemented to reduce user interaction. The algorithm was tested with 10 human knees with different levels of OA which were segmented twice. The global CV was 0.57% for 3D cartilage thickness and 1.69% for cartilage volume demonstrating the good performance of the technique.

                  1543.     A Novel Pixel-By-Pixel Texture Analysis Technique Improves Frequency Resolution of Local MS Spectra

Sylvia Drabycz1, J Ross Mitchell1

1University of Calgary, Calgary, Canada

Previous studies have demonstrated that local spectral analysis using the polar S-transform (PST) can help discriminate between normal-appearing white matter (NAWM) and active as well as inactive multiple sclerosis (MS) lesions on MR images. However, the very large number of computations required for even moderately sized images relegates the PST to a region-of-interest approach, which reduces the resulting spectral resolution. We introduce a novel spectral analysis technique that uses circularly symmetric windows in the frequency domain and averages the contribution of each complex spectral contribution. Our method produces a complex, and fully invertible, 3D local frequency domain with complete spectral resolution.

                  1544.     A Common De-Scalping Procedure for Various Different MRI Proctols

Ankur Purwar1, RKS Rathore1, RK Gupta2, MK Sarma1, G Bayu1, D Rathore1, R Trivedi2, JK Singh1, Anup Singh1, S Verma1

1IIT Kanpur, Kanpur, India; 2SGPGIMS Lucknow, Lucknow, India

De-scalping the brain is a very useful procedure with enormous applications in visualization, surface rendering, decreasing the complexity of subsequent processing algorithms, and the like. Many applications related to brain imaging either require, or benefits from the ability to accurately segment brain from the non-brain tissue. For example, (a) in the registration of b0-images to DW images in DT-MRI, both b0 and DW images often contain considerable portions of eyeballs, skin etc. that cause problems in the registration process, which gets improved once these non-brain parts of the images are removed, (b) a second application of de-scalping is in tissue-type segmentation, which helps in isolating brain tissue from other parts of the stack such as CSF, (c) in the removal of strong ghosting effects which can occur with EPI and (d) creating probabilistic atlases from large groups of subjects. This work describes an automatic procedure for de-scalping in the brain for MRI for scans with axial orientation. The procedure has effective in all types of brain imaging techniques including T1, T2W, PD, and T2W-EPI.

                  1545.     Computer-Assisted Segmentation of White Matter Lesions in 3D MR Images, Using Support Vector

Zhiqiang Lao1, Dinggang Shen1, Elias R. Melhem1, Nick R. Bryan1, Christos Davatzikos1

1University of Pennsylvania, Philadelphia, Pennsylvania, USA

We present a computer-assisted white matter lesions (WMLs) segmentation method, based on local features extracted from multi-parametric MRI sequences. A Support Vector Machine (SVM) classifier is first trained on expert-defined WML’s, and is then used to classify new scans. Subsequent post-processing analysis further reduces false positives by utilizing anatomical knowledge and measures of distance from the training set. Cross-validation on 35 patients from 3 different imaging sites with WMLs of varying sizes, shapes and locations tests the robustness and accuracy of the proposed segmentation method, compared to the manual segmentation results from two experienced neuroradiologists.


Spectroscopy Methodology:  Miscellaneous

Hall D                                   Thursday 13:30-15:30

                  1576.     Reproducibility Study of Whole-Brain Spectroscopic Imaging with Automated Quantification

Meng Gu1, Dirk Mayer1, Edith Sullivan, Adolf Pefeeferbaum, Daniel Spielman1

1Stanford University, Stanford, USA

A reproducibility study of proton magnetic resonance spectroscopic imaging of the human brain was conducted to evaluate the reliability of an automated 3D in vivo spectroscopic imaging acquisition and associated quantification algorithm.  The complete study consisted of 7 healthy adult subjects scanned within a one month interval to assess inter-subject variability and one subject scanned six times to assess intra-subject variability. The observed inter-subject and intra-subject coefficients-of-variation from five regions-of-interest were comparable to those reported for single-voxel acquisitions from similar ROIs. These results demonstrate that reproducible whole-brain 1H-MRSI data can be robustly obtained with the proposed methods.

                  1577.     Imaging of Physiologic Lactate Concentrations by SelMQC Spectroscopy with Hadamard Slice Selection
                                on a Clinical Scanner

Eric Albert Mellon1, Stephen J. Pickup1, Gamliel Isaac1, Sueng Cheol Lee1, Edward J. Delikatny1, Ravinder Reddy1, Jerry D. Glickson1

1University of Pennsylvania, Philadelphia, Pennsylvania, USA

Selective Homonuclear Multiple-Quantum Coherence-transfer (Sel-MQC) lactate spectroscopy has shown excellent promise for the detection of lactate with full fat and water suppression. While 2D versions of this technique have been published on animal scanners and very recently a 3D technique has been proposed, to our knowledge these techniques have not been implemented on a clinical scanner. Here a 2D phase encoded, 1D Hadamard encoded Sel-MQC sequence is demonstrated in single and double quantum modes for the detection of physiologic levels of lactate in phantoms on a 3T clinical scanner with a standard coil for the goal of future clinical studies.

                  1578.     New Technique for Simultaneous Acquisition of Metabolite and Water Signals in 1H-CSI

Toru Shirai1, Yukari Yamamoto1, Yoshitaka Bito1, Satoshi Hirata2

1Hitachi, Ltd., Kokubunji-shi, Japan; 2Hitachi Medical Corporation, Kashiwa-shi, Japan

We propose a new technique for simultaneous acquisition of metabolite and water signals in CSI. The pulse sequence of this technique includes a CHESS pulse whose amplitude is switched alternately in accordance with phase encoding steps in order to reverse the polarity of the water signal. Because the water signal is shifted to the top and bottom of the reconstructed image, the metabolite signal is separable from the water signal. The results of phantom experiments showed that this technique was effective in suppressing water signal, which suggests the usefulness of the proposed method.

                  1579.     Lipid Suppression with Variable-Density Spiral Trajectory for Volumetric Brain CSI

Joonsung Lee1, Borjan Gagoski1, Elfar Adalsteinsson1

1Massachusetts Institute of Technology, Cambridge, Massachusetts, USA

Estimates of cortical brain metabolites using chemical shift imaging (CSI), especially those of NAA, are severely hampered by strong, subcutaneous lipid signals. by reducing the spatial side lobes and using the variable-density spiral trajectories, lipid signals can be bound spatially to reduce the amount of lipid signal leakage. A 3D filter was designed and demonstrated in variable-density spiral-based trajectory for volumetric brain CSI. Excellent lipid suppression was achieved via the filter function without minimal SNR tradeoffs.

                  1580.     Improved Spatial Coverage for 3D MRSI by Automatic Placement of Outer-Volume Suppression
                                Saturation Bands

Eugene Ozhinsky1, 2, Sarah J. Nelson1, Daniel B. Vigneron1

1University of California San Francisco, San Francisco, California , USA

To improve coverage of the brain, while simultaneously reducing lipid contamination, we have developed a technique for automatic optimization of sat band position and orientation that simultaneously maximizes coverage of subcutaneous fat and minimizes the portion of brain tissue that is removed. This allows to prescribe a much larger PRESS box and provides MR spectra from a significantly larger volume of the brain.

                  1581.     Off-Resonance Effects in Non-Conventional Spectroscopic Imaging

Claudiu Schirda1, Fernando Boada2

1State University of New York at Buffalo , Buffalo, New York, USA; 2University of Pittsburgh, Pittsburgh, Pennsylvania, USA

Fast spectroscopic imaging enables resolving the spectral information at much higher spatial resolutions compared to classical Chemical Shift Imaging (CSI) experiments, in shorter scan times. Besides fast CSI techniques that sample k-space on a Cartesian grid (e.g. Dixon), a number of non-conventional approaches employing non-Cartesian trajectories have been developed. Among them are stochastic trajectories, PREP, spiral and rosette trajectories. We theoretically analyze and experimentally demonstrate the off-resonance effects associated with these non-conventional encoding techniques.

                 1582.     High Speed Magnetic Resonance Spectroscopic Imaging Using Wavelet Encoding and Parallel Imaging

Yao Fu1, Hacene Serrai1

1National Research Council Institute for Biodiagnostics, Winnipeg, Canada

This work describes a new MRSI technique resulting from combination of wavelet encoding and parallel imaging. The purpose of this work is to reduce acquisition time in MRSI and minimize the SNR loss inherent to parallel imaging. Similar to Fourier encoding with parallel imaging where a predetermined number of k-space lines are skipped depending on the speed factor R, fewer lines in the wavelet domain, which resemble to k-space for wavelet encoding, are omitted and reconstructed from the acquired signals. As a result, reduction of acquisition time achieved by a factor R with minimum loss of SNR as compared to Fourier encoding.

                  1583.     Optimal Number of Excitations for a Rosette Spectroscopic Imaging Experiment

Claudiu Schirda1, Fernando Boada2

1State University of New York at Buffalo , Buffalo, New York, USA; 2University of Pittsburgh, Pittsburgh, Pennsylvania, USA

Fast spectroscopic imaging enables resolving the spectral information at much higher spatial resolutions compared to classical Chemical Shift Imaging (CSI) experiments, in shorter scan times. Besides fast CSI techniques that sample k-space on a Cartesian grid (e.g. Dixon), a number of non-conventional approaches employing non-Cartesian trajectories have been developed. Among them are stochastic trajectories, PREP, spiral and rosette trajectories. We theoretically analyze and experimentally demonstrate the off-resonance effects associated with these non-conventional encoding techniques.

                  1584.     Breath-Hold High Resolution Spectroscopic Imaging of the Liver Using Rosette Trajectories

Claudiu Schirda1, 2, Fernando Boada2

1State University of New York at Buffalo , Buffalo, New York, USA; 2University of Pittsburgh, Pittsburgh, Pennsylvania, USA

Nonalcoholic fatty liver disease (NAFLD) affects an estimated 14% to 30% of the general population in the United States, with an important number of these patients progressing to nonalcoholic steatohepatitis (NASH), cirrhosis or die of liver failure. The earliest manifestation of NAFLD/NASH is hepatic steatosis (fatty infiltration of the liver) and regrettably, the utility of liver biopsy is very limited. MRI techniques based on a two-point or multi-point Dixon methods were demonstrated for fat-water separation and fat fraction quantification in liver. However, FT based techniques are much more susceptible to even minimal amounts of motion compared to methods using center-out k-space trajectories. We propose the use of Rosette Spectroscopic Imaging (RSI) for fat-water separation in liver.

                  1585.     Impact of T2* Decay on the Quantification of Hepatic Steatosis with MRI

Venkata Veerendranadh Chebrolu1, Huanzhou Yu2, Ethan K. Brodsky1, Charles McKenzie, Scott B. Reeder1

1University of Wisconsin Madison, Madison, USA; 2GE Healthcare, Menlo Park, California , USA

This study investigates the impact of T2* decay on the ability of MRI using water-fat separation techniques to quantify fatty infiltration of the liver. A new generic analytical model, that includes the effects of line-width caused by T2* decay, is developed to the quantity the amount of different chemical species present in a specimen using MRI. The model is used to demonstrate the effect of line-width on the quantification of fat-fraction in non-alcoholic fatty liver disease. Our results demonstrate the need for methods that compensate for the effects of T2* decay when attempting to measure hepatic fat content.

                  1586.     Comparison Between TmDOTP5- and TmDOTMA- Temperature Probes in Rat Brain

Daniel Coman1, Fahmeed Hyder1

1Yale University, New Haven, USA

In the last decade, a new non-invasive method for temperature and pH determination was developed based on temperature and pH dependencies of the 1H chemical shifts emanating from TmDOTP5-. More recently a similar temperature-sensitive probe was introduced, based on temperature dependence of the methyl 1H chemical shift of TmDOTMA-, which is pH independent. Here we report detection of TmDOTMA- in the rat brain and compare in vivo temperature distributions obtained using TmDOTP5- and TmDOTMA- complexes. Additionally we discuss advantages and/or disadvantages of using these two complexes as exogenous probes for temperature and pH sensing in rat brain.

                  1587.     Assessment of Lipids in Skeletal Muscle: Comparison of the Water and Fat Referenced Spectroscopy

Jan Weis1, Lars Johansson1, Francisco Ortiz-Nieto1, Håkan Ahlström1

1Uppsala University Hospital, Uppsala, Sweden

The unsuppressed water line is almost exclusively used as a concentration reference in quantitation of the muscle lipids. In spectroscopy of the skeletal muscle, the necessity for relaxation correction of water reference is a fundamental disadvantage. Alternatively, the fat signal can be used as the internal standard. In this study we compare both methods for the determination of lipid content in human skeletal muscle: relaxation effects sensitive water referenced single-voxel 1H MRS and relaxation effects robust high-spatial-resolution MRSI with fat (yellow bone marrow) as the internal or vegetable oil as the external concentration reference.

                  1588.     Design of Quality Control Measures for a Multi-Site Clinical Trial of Breast MRS - ACRIN 6657

Patrick J. Bolan1, Michael Garwood1, Mark A. Rosen2, Anthony Levering3, Jeffrey D. Blume4, James Gimpel3, Laura J. Esserman5, Nola Hylton5

1University of Minnesota, Minneapolis, Minnesota, USA; 2University of Pennsylvania, Philadelphia, USA; 3ACRIN, Philadelphia, USA; 4Brown University, Providence, Rhode Island, USA; 5University of California, San Franciso, San Francisco, California , USA

The American College of Radiology Imaging Network (ACRIN) and the I-SPY network are supporting a multi-site clinical trial using quantitative single voxel spectroscopy (SVS) to quantify early response to neoadjuvant therapy in 140 patients. Ensuring that the spectroscopic [tCho] measurements can be performed with sufficient accuracy and precision to address this clinical aim is a difficult challenge, especially considering that field strength, scanner manufacturer, breast coil, and sequences will vary between sites. The goal of this abstract is to describe the design of the study and its quality control measures and present initial findings from the quality control phantom scans.

                  1589.     P-31 MRS for Detection of Myocardial Microvascular Disease in Latino Type-I Diabetes Mellitus Patients

Hee-Won Kim1, Gerald M. Pohost1, Padmini Varadarajan2, Milena Ocon1, Rafit Drori3, Patrick Colletti1, Adina E. Zeidler1

1University of Southern California, Los Angeles, California , USA; 2Loma Linda University Medical Center, Loma Linda, California , USA; 3Hillel Yaffe Medical Center, Hadera, Israel

The change of high energy phosphate (HEP) level in the heart of Latino Type-1 diabetes mellitus (DM) patients was evaluated during rest and stress at 3T in order to identify impaired left ventricular function that is associated with reversible, exercise-induced metabolite alteration in Type-1 DM patients. The significant drop of PCr/ATP was found during handgrip stress among 28% of the patient compared with normal control. It may suggest systemic microvascular disorder as bioenergetic changes present among Type-1 DM patients and the non-invasive 31P cardiac MRS may facilitate the prediction of cardiomyopathy in such patients.


Quantitative MRS of Glutathion 2 13C Labeled Metabolites

Hall D                                   Thursday 13:30-15:30

                  1637.     Adaptive Spectral Registration Method for Glutathione Measurement Using J-Difference Editing

Li An1, Yan Zhang1, David M. Thomasson1, Lawrence L. Latour1, Eva H. Baker1, Jun Shen1, Steven J. Warach1

1National Institutes of Health, Bethesda, Maryland, USA

In this work, we present a fully automated spectral registration method for frequency, phase, and linear baseline corrections. Instead of using a Lorenzian and/or Gaussian curve, target spectra for spectral registrations are generated from the data by a fitting and selection process. Spectral registrations are performed using broader ranges of spectral data instead of just one peak in the spectrum. A linear baseline correction is also done in the spectral registration process, which is important for GSH measurement where residual water baseline is a bigger problem than for other J-difference editing experiments.

                  1638.     Strategy for Yield Enhancement in Glutathione Double-Quantum Filtering

Changho Choi1, Nicholas J. Coupland2, Peter Seres2

1University of Texas Southwestern Medical Center, Dallas, USA; 2University of Alberta, Edmonton, Canada

A new strategy for yield enhancement of glutathione (GSH) double-quantum (DQ) filtering for detection of the 2.95-ppm resonances is proposed. Following the double-quantum preparation and DQC encoding, a spectrally-selective 180° RF pulse is employed to interchange DQC and ZQC, followed by another DQC encoding step. With the large bandwidth of adiabatic 180° pulses for space localization, an edited signal amplitude ~100% with respect to the 90°-acquired multiplet can be achieved at an optimal sequence time. Preliminary results of numerical simulation and phantom tests are presented.

                  1639.     A New Strategy to Measure Reduced Glutathione (GSH) at 3 and 4 Tesla Using an Optimized STEAM

Shaolin Yang1, Yihong Yang1

1National Institute on Drug Abuse, NIH, Baltimore, Maryland, USA

The reduced form of glutathione (GSH) is a major intracellular antioxidant. Due to its strong spectral overlap with other metabolites, spectral editing or LCModel analysis of short-echo PRESS or STEAM spectra has been suggested to measure GSH. We propose here a new strategy to resolve the spectral overlap between GSH and other metabolites by optimizing the timing parameters of a standard STEAM sequence through spectral simulation. The results show that the proton resonances of GSH at 2.54 ppm can be resolved from other metabolite resonances at 3T and 4T, which provides a potential to significantly improve the quantification of GSH. 

                  1640.     Practical Glutathione Measurement in Human Brain at 3 T

Li An1, Yan Zhang1, David M. Thomasson1, Lawrence L. Latour1, Eva H. Baker1, Jun Shen1, Steven J. Warach1

1National Institutes of Health, Bethesda, Maryland, USA

This work demonstrates the ability to consistently measure GSH in human brain on a commercial 3 T scanner with a scan time of nine minutes. A relatively long TE of 131 ms yields good GSH signal, smaller water baseline, as well as near in-phase GSH and co-edited NAA/NAAG resonances. A novel spectral registration method was also developed to perform frequency, phase, and linear baseline corrections without human intervention. From scanning normal volunteers and stroke patients, this work appears to be a step forward toward practical use of GSH measurement in clinical studies.

                  1641.     Simultaneous Detection of Antioxidant Concentrations and Their T2 Using Double Edited 1H MRS
 [Not Available]

Melissa Terpstra1, Dinesh Deelchand1, Ivan Tkac1, Pierre-Gilles Henry1

1University of Minnesota, Minneapolis, Minnesota, USA

Quantification of ascorbate (Asc) and glutathione (GSH) concentrations may be useful to study neurodegenerative disease. T2 might differ between patients and controls. The goal of this study was to measure T2 along with Asc and GSH concentrations in the human occipital cortex in vivo. Asc and GSH resonances were detected at multiple echo times using DEW MEGA-PRESS edited 1H MR spectroscopy at 4 T. Reasonable T2 were measured in one subject without compromising signal to noise for detection of Asc and GSH. Data can be averaged over several subjects to reduce uncertainty in measurement of T2.

                  1642.     Direct Measurement of Malate-Aspartate Shuttle Activity at Different Cytosolic Redox States in Intact
                                Hearts Using 13C NMR Spectroscopy

Ming Lu1, 2, Suhanti Banerjee1, Gerald M. Saidel1, Xin Yu1

1Case Western Reserve University, Cleveland, USA

To examine the effect of cytosolic redox state (NADH/NAD+) on malate-aspartate (M-A) shuttle activity in hearts, oxidative cardiac metabolism was studied using 13C NMR spectroscopy. Isolated rat hearts were perfused with either 2.5mM [2-13C]acetate or 2.5mM [2-13C]acetate plus glucose and lactate to increase cytosolic NADH/NAD+. Tricarboxylic acid (TCA) cycle flux (VTCA) and M-A shuttle flux (VM-A) were determined by least-square fitting of a novel multi-domain kinetic model of cardiac metabolism to dynamic 13C NMR spectra. Our results showed that VTCA was unaltered by changes in cytosolic redox state, whereas VM-A increased by 38% at high cytosolic NADH/NAD+.

                  1643.     Mathematical Model of Glial Metabolism Assessed Using C1-Labeled Acetate

Bernard Lanz1, Kai Uffmann1, Matthias T. Wyss2, Bruno Weber2, 3, Alfred Buck2, Rolf Gruetter1, 4

1Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 2PET Center, University Hospital Zurich, Zurich, Switzerland; 3University Zurich, Zurich, Switzerland; 4Universities of Lausanne and Geneva, Lausanne and Geneva, Switzerland

Combining PET and NMR for cerebral labeling studies in vivo requires a common  model to compare and combine the results given by both techniques. The aim of the present study is to develop a metabolic model of neuro-glial metabolism suitable to assess metabolic rates resulting from an infusion of acetate labeled at the C1 position and to apply this model to experimental radiotracer time courses following  11C[1]-acetate infusion. We developed and applied successfully a model based on traditional NMR modeling to simulate and fit PET data.

                  1644.     Simultaneous Measurement of Neuronal and Glial Metabolism in Rat Brain In Vivo Using Co-Infusion
                                of [1,6-13C2]Glucose and [1,2-13C2]Acetate

Dinesh K. Deelchand1, Chris Nelson1, Alexander A. Shestov1, Kamil Ugurbil1, Pierre-Gilles Henry1

1University of Minnesota, Minneapolis, Minnesota, USA

In this work the feasibility of measuring neuronal-glial metabolism in rat brain in vivo using co-infusion of [1,6-13C2]glucose and [1,2-13C2]acetate was investigated. The distinct 13C spectral pattern observed in glutamate and glutamine directly reflected the fact that glucose was metabolized primarily in the neuronal compartment and acetate in the glial compartment. Time courses of concentration of singly and multiply-labeled isotopomers of glutamate and glutamine were obtained. We expect that dynamic metabolic modeling of these new 13C isotopomer data using two-compartment neuronal-glial models will lead to a more precise determination of metabolic rates, particularly the rate of glutamate-glutamine cycle.


Multi-Modality Contrast Agents

Hall D                                   Thursday 13:30-15:30

                  1695.     Characterization of Graphite/metal Core-Shell Nanocrystals as Multi-Modality Contrast Agents for
                                Macrophage and Atherosclerosis Imaging

Hisanori Kosuge1, Masahiro Terashima1, Sarah Sherlock, Jin Hyung Lee, Hongjie Dai, Michael V. McConnell

1Stanford University, Stanford, California , USA

The novel graphite/metal core-shell nanocrystals (CN) are effectively taken up by macrophages in vitro and in vivo. This particles show promising properties as MRI contrast agents for noninvasive evaluation of atherosclerosis.

                  1696.     A Novel Redox-Responsive, Dual-Modality MRI/optical Imaging Probe  [Not Available]

Chuqiao (Tom) Tu1, Ryan Ngao1, Angelique Louie1

1UC Davis, Davis, California , USA

We have developed a small molecule gadolinumm contrast agent that changes conformation in response to redox activity, thereby modulating relaxivity.  The synthesized contrast agent responds to NADH at biologically relevant concentrations.  Significant changes in MR image contrast are produced in response to chemical reductants and oxidants.

                  1697.     Pharmacokinetics and Bio-Distribution of a Novel Silica-Based Multimodal Nanoparticle

Matti M. van Schooneveld1, Esad Vucic2, Rolf Koole1, Yu Zhou2, Cheuk Y. Tang2, Klaas Nicolay3, Andries Meijerink1, Zahi A. Fayad2, Willem J.M. Mulder2

1Utrecht University, Utrecht, Netherlands; 2Mount Sinai School of Medicine, New York, New York, USA; 3Eindhoven University of Technology, Eindhoven, Netherlands

We investigated the pharmacokinetics and bio-distribution of a novel silica-based multimodal nanoparticle. This probe consists of a quantum dot (for fluorescence imaging) incorporated in a 35 nm silica nanoparticle, which is coated by paramagnetic (for MRI) and pegylated lipids to overcome the limited bio-applicability of silica particles. MRI, optical techniques, relaxation measurements, and ICP-MS were used to determine the blood half-life value and the tissue distribution at anatomical and cellular level. A 10-fold increase in the half-life value was observed in case the particles were lipidic coated as compared to non-coated particles (t1/2 = 17 min vs. 180 min).

                       1698.     Kinetics of Avidin-Induced Clearance of Biotinylated Bimodal Liposomes for Improved MR Molecular

Geralda A.F. van Tilborg1, Gustav J. Strijkers1, Emilie M. Pouget1, Chris P.M. Reutelingsperger2, Nico A.J.M. Sommerdijk1, Klaas Nicolay1, Willem j.m. Mulder3

1Eindhoven University of Technology, Eindhoven, Netherlands; 2University of Maastricht, Maastricht, Netherlands; 3Mount Sinai School of Medicine, New York, USA

Bimodal liposomes, carrying large amounts of gadolinium-lipids, were recently proposed as potent contrast agents for MR molecular imaging. These nanoparticles display a long circulation time, which enables massive accumulation at the targeted site but also keeps the target to background ratio low for a prolonged period. In this study an avidin chase was designed to rapidly clear paramagnetic biotinylated liposomes from the blood circulation. Avidin-induced alterations in the biodistribution and blood clearance kinetics were studied. The ability to rapidly clear circulating contrast agent opens up exciting possibilities to study targeting kinetics and to optimize nano-particulate contrast agent formulations.

                  1699.     In Vivo T1 and T2 Effects of Paramagnetic Quantum Dot Based Contrast Agents for Molecular Magnetic
                                Resonance Imaging

Marlies Oostendorp1, 2, Kim Douma2, Tilman M. Hackeng2, Anouk Dirksen2, Mark J. Post2, Marc A.M.J. van Zandvoort2, Walter H. Backes1, 2

1Maastricht University Hospital, Maastricht, Netherlands; 2Maastricht University, Maastricht, Netherlands

Paramagnetic quantum dots (pQD), Gadolinium-loaded fluorescent semiconductor nanoparticles, are becoming more popular as molecular MRI contrast agent. Besides decreasing the local T1 relaxation time, it is expected that the semiconductive properties of pQD result in field inhomogeneities, which contribute to T2 relaxation time shortening. It is therefore unknown whether T1 or T2 based methods show the strongest contrast enhancement upon pQD injection. Here, we applied a quantitative molecular MRI method to analyze tissue T1 and T2 and the changes thereof induced by pQD targeted to the angiogenic tumor vasculature. Significant differences were only found for T1 based effects.

                  1700.     MR and Optical Target Imaging for Intracranial Tumors with Chlorotoxin Conjugated Nanoprobes

Donghoon Lee1, Conroy Sun1, Omid Veiseh1, Chen Fang1, Stacey Hansen2, Miqin Zhang1, James Olson2, Richard Ellenbogen1

1University of Washington, Seattle, Washington, USA; 2Fred Hutchinson Cancer Research Center, Seattle, Washington, USA

Nanoprobes were developed for MR and optical target imaging of intracranial tumors. Currently, nanoconjugates have been limited in target imaging for intracranial tumors due to insufficient accumulation within tumor and inability to cross the blood brain barrier (BBB). Our developed nanoconjugates were iron oxide nanoparticles coated with PEG (polyethylene glycol)-chitosan conjugated with chlorotoxin. Images acquired by MR and optical imaging revealed specific particle uptakes by intracranial tumors for 2-5 days post injections and evidence of the nanoprobes passing through the BBB for mouse model with BBB intact. Histology data also supported the results.

                  1701.     Multimodal Imaging of Luciferase Transgenic Dendritic Cells Using Magnetic Resonance Imaging (MRI)
                                Based Tracking After Allogeneic Hematopoietic Cell Transplantation

Wilfried Reichardt1, Robert Zeiser2, Jürgen Hennig1, Dominik von Elverfeldt1

1University of Freiburg, Freiburg, Germany; 2Stanford University School of Medicine, Stanford, USA

Synopsis:Insight into the trafficking pattern of dendritic cell (DC) populations into lymphoid and non-lymphoid tissues after allogeneic hematopoietic cell transplantation (aHCT) is critical to understand the complex processes that regulate graft-versus-host disease. We were able to generate a platform for in vivo bioluminescence (BLI) and magnetic resonance imaging (MRI) based cell trafficking studies by labelling luciferase transgenic DC with superparamagnetic iron oxide (SPIO) Nano particles bound to a murine IgG antibody.

                  1702.     Dual Modality Imaging of Phosphatidylcholine-Specific Phospholipase C in DU145 Prostate Cancer
         Cells and Solid Tumors

Theresa Meganne Mawn1, Daniel-Joseph Leung1, Nancy Beardsley1, Anitoliy Popov1, E. James Delikatny1

1University of Pennsylvania, Philadelphia, Pennsylvania, USA

We have employed a dual modality approach to detect changes in lipid metabolites and phosphatidylcholine-specific phospholipase C (PC-PLC) activity in prostate cancer cells and solid tumors. MRS studies have consistently revealed the presence of elevated levels of phosphocholine (PCho) in various types of cancer. However, it remains uncertain whether these elevations are due to choline transport and choline kinase, or occur catabolically through the action of PC-PLC. By combining MRS with a near-infrared (NIR) PC-PLC-activated optical imaging probe, we are able to directly image the relative contributions of the anabolic and catabolic pathways to PCho elevations in cancer.

                  1703.     Molecular NMR and EPR in Vivo Detection of Inflammation Using Specific E-Selectin Targeted Iron Oxides

Kim Anne Radermacher1, Nelson Beghein1, Sebastien Boutry2, Sophie Laurent2, Luce Vander Elst2, Robert N. Muller2, Benedicte F. Jordan1, Bernard Gallez1

1Université Catholique de Louvain, Brussels, Belgium; 2University of Mons-Hainaut, Mons, Belgium

The aim of the study was to develop a molecular marker for non invasive diagnosis and monitoring in the early stages of inflammation. An E-selectin ligand was coupled to ultrasmall particles of iron oxide (USPIO). After intravenous injection of the grafted or ungrafted USPIO, their concentration was evaluated in inflamed muscle ex vivo by an EPR X-band and in vivo by an EPR L-band, as well as by MRI. All three methods demonstrate that the specific targeting of grafted USPIO was twice higher in inflamed tissues than using the ungrafted ones.


Non-Proton MRI

Hall D                                   Thursday 13:30-15:30                                                                                                                                           

                  1734.     Natural Abundance 17O NMR Spectroscopy of Rat Brain In Vivo

Robin A. de Graaf1, Peter B. Brown1, Kevin L. Behar1

1Yale University, New Haven, Connecticut, USA

Despite the rich abundance of oxygen in biologically relevant compounds, oxygen detection by NMR is limited largely by the low natural abundance of oxygen-17 (0.037%) and the broad resonances (spin 5/2). However, the favorable T1 relaxation constants, together with the increased spectral dispersion and sensitivity at high magnetic fields allowed the detection of natural abundance 17O NMR spectra from rat brain in vivo. A large number of resonances originating from phosphate, sulfate and carbonyl groups were readily detected.

                  1735.     Evaluation of Lung Tumor Oxygenation in Rats Using FREDOM

Jesus Pacheco1, 2, Dawen Zhao1, Vikram D. Kodibagkar1, Angelina Contero1, Debabrata Saha3, Sebastian Cerdan2, Ralph P. Mason1

1University of Texas Southwestern Medical Center, Dallas, Texas, USA; 2Instituto de Investigaciones Biomédicas "Alberto Sols" - CSIC, Madrid, Spain; 3University of Texas Southwestern Medical Center, Dalas, Texas, USA

Hypoxia is recognized to influence tumor response to therapy. 19F MRI using the reporter molecule hexafluorobenzene has been demonstrated to measure pO2 dynamics in tumors growing in animals- the  FREDOM  approach. Here, we explore the use of  FREDOM   to evaluate pO2 distributions and response to hyperoxic gas breathing in H460 lung tumor xenografts growing in rats. Oxygenation is found to range from hypoxia to well oxygenated and the H460 tumors are found to be highly responsive to hyperoxic gas breathing. The regions, which are initially best oxygenated showed greatest response. These results show further application of 19F MRI oximetry.

                  1736.     Fluorinated Anaesthetics Uptake Kinetic Investigation on Large Animal Model Using 19F MRS/MRI

Maxim Terekhov1, Alexander Scholz2, Ursula Wolf1, Julien Rivoire1, Wolfgang Schreiber1

1Mainz University Medical School, Mainz, Germany; 2Mainz University Medical School,, Mainz, Germany

MRS and MRI of drugs are emerging tools in the development and understanding of pharmacons. Some drugs, e.g. the inhaled anesthetics such as sevoflurane, embody fluorine. In these cases, 19F MRI allows for in vivo imaging.without background signal. We established a large animal model for NMR/MRI investigations of fluorinated anesthetics at 1.5T medical scanner that may be considered as a further step towards human studies. This imaging and spectroscopy techniques may allow for a regional analysis of pharmacokinetic and better understanding of molecular interactions of inhaled anesthetics.

                  1737.     Phase Contrast MRI of 19F and 3He Gas Flow: Phantom Studies

Daniel Kalthoff1, 2, Ursula Wolf1, Kerstin Münnemann1, Wolfgang Günther Schreiber1

1Mainz University Medical School, Mainz , Germany; 2Max Planck Institute for Neurological Research, Cologne, Germany

A method of phase contrast MRI was implemented to study flow of 3He and especially 19F gases which are currently used in lung imaging. Experiments were performed on a custom-made gas flow phantom that produced a continuous gas flow with in-vivo-like characteristics in flow rates and geometry. Turbulent and laminar flow were observed as expected in C4F8 and 3He respectively. A comparison of MRI data to simultaneous flow sensor measurements showed excellent agreement and verified the accuracy of the presented method. Thus, phase contrast MRI of 19F and 3He appears to suitable for quantitative investigation of lung ventilation.

                  1738.     Reduction of Chemical Shift Artifacts in 19F Imaging Utilizing Coil Sensitivities

Oliver Lips1, Jochen Keupp1

1Philips Research Europe, Hamburg, Germany

19F-MRI bears potential as a tracer technique for applications in diagnosis and therapy monitoring when combined with fluorine-labeled agents. However, 19F-MRI suffers from chemical shift (CS) artifacts due to multi-line spectra of typical 19F-agents or the presence of multiple agents exhibiting different CS. Hence, countermeasures are needed, which do not spoil the SNR or significantly increase scan time. A concept is presented, which utilizes different coil sensitivity profiles to correct for CS artifacts applying a SENSE-like algorithm in the frequency encoding direction. Simulations and initial experiments were performed. The results indicate, that the method has potential to improve multi-line 19F-imaging.

                  1739.     19F MR for Drug Delivery Research

Xin Liu1, Zhong-Xing Jiang1, Y. Bruce Yu2, Eun-Kee Jeong1

1University of Utah, Salt Lake City, USA; 2University of Maryland, College Park, USA

1H MR imaging of water protons in tissue is widely used for studying the pharmacokinetics of Gd-chelate based endogenous contrast agent. The concentration of the delivered compound is indirectly measured by analyzing the change in the proton MRI signal intensity. this method is not practical in most of dynamic MR imaging due to the long imaging time for T1 mapping. In this report, 19F MRI is presented as an alternative method to access the drug quantity. The concentration of fluorine compound is directly proportional to the 19F signal in density weighted 19F-MRI.

                  1740.     Combining Tissue Segmentation with Quantitative 31P and 1H MRSI Can Resolve the Distribution of
                                Three Trimethylamine Components in Gray and White Matter

Joerg Magerkurth1, Ulrich Pilatus1

1Johann Wolfgang Goethe Universität, Frankfurt a. M., Germany

Voxelwise coregistration for combining quantitative 31P and 1H MR spectroscopy ishampered by the rather large voxel size and the poor point-spread-function (PSF) of 31PMRSI data.  The problem can be addressed by minimizing the partial volume effects usingimage segmentation and linear regresson analysis as described previously for 31P  and 1H. The approach was evaluated to determine concentration differences between gray and whitematter for the three components of the trimethylamine (tCho) signal at 3.2 ppm in 1HMRSI. This study demonstrates that application of tissue segmentation in combination with quantitative 31P and 1H MRSI can resolve the distribution of these components in gray andwhite matter.

                  1741.     Preliminary Results of 31P MR Imaging at 9.4T Using a RARE Sequence

Aiming Lu1, Ian C. Atkinson1, Xiaoong Joe Zhou1, Theodore Claiborne1, Keith R. Thulborn1

1Univ. of Illinois at Chicago, Chicago, Illinois, USA

31P MRI can provide quantitative bioenergetic information of human brain non-invasively. However, quantitative determination of the spatial distribution of 31P is challenging due to its low MR sensitivity. With the increased sensitivity at 9.4T, initial 31P images with reasonable SNR have been obtained on a phantom with concentration comparable to that of PCr in human brain within 10 minutes using a RARE sequence, which demonstrates the potential of quantitative 31P metabolic imaging at 9.4T.

                  1742.     Optimization of Xenon Biosensors for Increased Sensitivity

Tyler Meldrum1, Monica A. Smith1, Leif Schroeder1, Thomas Lowery1, David Wemmer1, Alex Pines1

1University of California, Berkeley, Berkeley, California , USA

We have developed a modular approach to xenon-based biosensor synthesis that facilitates optimization of the sensors for increasing sensitivity.  By synthesizing a biosensor with a negatively-charged side chain, together with increased temperature (37 C) and the HYPER-CEST detection method, we can detect biosensor concentrations as low as 10 nM.

Text Box:  
                  1743.     Measurement of Pressure from the Diffusion Coefficient of 3He Gas

Jim M. Wild1, Steven R. Parnell1

1University of Sheffield, Sheffield, UK

Non-invasive measurement of pressure with NMR could have a variety of applications in-vivo (e.g. measurement of blood pressure) and in non-medical applications (e.g. pressure jets in fluid dynamics). In this work an inverse relation between the pressure of 3He and the measured (apparent) diffusion coefficient (D) was observed using intermediate diffusion time pulsed gradient spin echo (PGSE) methods. Extension of the technique for measuring pressure in-vivo in micro bubbles is proposed using different gas mixtures and short time scale diffusion sequences.

                  1744.     Are We Nearly There Yet? Cardiac 23Na Imaging at 3T Using a 3D Ultrashort TE Acquisition and
                                 Phased-Array Reception

Matthew David Robson1, Stefan Neubauer1

1Oxford University, Oxford, UK

We have implemented and evaluated a 3D stack of spokes acquisition at 3T using an 8-channel phased array sodium coil.  This incorporates an ultra-short TE readout, and can be run as an SSFP sequence.  This combination of technologies boosts the signal to noise, and provides higher image quality than have previously been demonstrated.


Diffusion Acquisition

Hall D                                   Thursday 13:30-15:30                                                                                                                                           

                  1798.     Effects of T2-Weighting on Optimum b-Value vs. SNR for ADC Measurements

Emine Ulku Saritas1, Jin Hyung Lee1, Dwight G. Nishimura1

1Stanford University, Stanford, California , USA

The optimization of b-value for two-point apparent diffusion coefficient (ADC) estimation schemes were previously investigated, assuming high signal-to-noise ratio (SNR) imaging and considering the effects of T2-weighting. Here, we investigate both the dependence of the optimum b-value on the SNR of the imaging scheme and also on the T2 of the tissue of interest. The results of this work are especially important for high-resolution diffusion-weighted imaging, which intrinsically suffers from low SNR.

                  1799.     Investigation of the Effects of Quality Weighting in Turboprop-DTI on the Diffusion Tensor Noise Due to
                                Brain Pulsation

Minzhi Gui1, Zhe Hu1, Konstantinos Arfanakis1

1Illinois Institute of Technology, Chicago, Illinois, USA

In the image reconstruction process for Turboprop diffusion tensor imaging (DTI), weights representing the quality of the data are estimated for each k-space blade (quality weighting, QW), and used during reconstruction to reduce the contribution of corrupted blades to the final image. This weighting procedure reduces artifacts due to: bulk motion, odd/even echo fluctuations, and other sources of k-space data variation between blades. In this work, the degree to which the QW also compensates for the increase in the total variance of the diffusion tensor due to cardiac-induced brain pulsation is investigated in both simulations and experiments on humans.

                  1800.     Evaluation of Spatial Normalization in Turboprop-DTI vs. SE-EPI-DTI

Huiling Peng1, Gady Agam1, Minzhi Gui1, Konstantinos Arfanakis1

1Illinois Institute of Technology, Chicago, USA

Accurate spatial normalization in diffusion tensor imaging (DTI) requires data with minimal artifacts. Conventional spin-echo echo-planar DTI (SE-EPI-DTI) suffers from severe B0-related image artifacts, which are prominent in certain brain regions, such as the brainstem, the frontal and temporal lobes. In contrast, Turboprop-DTI is relatively immune to image artifacts caused by magnetic field inhomogeneities. In this study, the performance of spatial normalization of DTI data obtained with SE-EPI-DTI and Turboprop-DTI was evaluated. The results demonstrated that, Turboprop-DTI may lead to more accurate spatial normalization than SE-EPI-DTI in regions where the latter suffers from magnetic field inhomogeneity artifacts.

                  1801.     Improvement of Diffusion Weighted Images with Reduced-View Radial Acquisitions

Yeji Han1, JinYoung Hwang2, HyunWook Park2

1University Hospital Freiburg, Freiburg, Germany; 2Korea Advanced Institute of Science and Technology, Republic of Korea

The proposed method aims to generate high-resolution diffusion-weighted (DW) images from a reduced number of projection data acquired with any kind of existing radial acquisition sequences. After acquiring less than a half of the required number of projection data, a reasonable estimation of the unacquired part of the projections is performed. After that, the proposed process refines the estimated projection data utilizing information of a full-resolution non-DW image. By using the proposed method, the acquisition time can be decreased while preserving the image quality. The simulation and experiment results show that the proposed method gives high-resolution DW images from the reduced-view projection dataset.

                  1802.     3T PROPELLER DiffusionTensor Imaging and Tractography : A Method for SAR Reduction
 [Not Available]

Hiroyuki Kabasawa1, Shigeki Aoki2, Yoshitaka Masutani2, Osamu Abe2, Kuni Ohtomo2

1GE Yokogawa Medical Systems, Hino-shi, Japan; 2The university of Tokyo, Bunkyo-ku, Japan

We demonstrated that VERSE implementation to PROPELLER reduced SAR and that helped to increase volume coverage and reduce scan time to clinically acceptable range. Slice coverage was increased from less than slice to 28 slices with 8sec of repetition time. The proposed method has potential for acquiring diffusion tensor images without compromising both image geometry accuracy and slice coverage.

                  1803.     SNR Improvement and Reduction of Geometric Distortion in 3D SingleShot Diffusion-Weighted
                               STimulated-EPI (3D Ss-DWSTEPI)

Xianfeng SHI1, Eugene Kholmovski1, Eun-Kee Jeong1

1University of Utah, Salt Lake City, USA

3D single-shot Diffusion-Weighted STimulated-EPI (3D ss-DWSTEPI) suffers from low SNR because it uses only half the diffusion-weighted magnetization stored into the longitudinal plane by a 90o RF and spoils another half. The degree of susceptibility-induced distortion in EPI-type acquisitions is inversely proportional to the speed of the k-space traveling in phase-encoding direction. To improve SNR and reduce the susceptibility-induced distortion, 3D ss-DWSTEPI in-plane readout is shorten by reducing FOV in phase-encoding direction. Parallel imaging technique has been implemented in 3D ss-DWSTEPI to reduce the geometric distortion and a method has been developed to improve SNR by utilizing whole diffusion-weighted magnetization.

                  1804.     Diffusion Weighted Fast Spin Echo PROPELLER at 9.4T

Irvin Teh1, 2, David J. Larkman1, Xavier Golay2, 3

1Imperial College London, London, UK; 2Singapore Bioimaging Consortium, Singapore, Singapore; 3National Neuroscience Institute, Singapore

Diffusion weighted imaging is widely used for studying tissue integrity and structure. Single shot DW-EPI is commonly used to improve motion robustness and efficiency, but suffers from lower resolution and magnetic field inhomogeneity effects. At high fields, image distortion and short T2* make multishot FSE methods more attractive. Periodically Rotated Overlapping ParallEL Lines with Enhanced Reconstruction (PROPELLER) has been demonstrated in humans as a self navigating and efficient sequence robust to motion artifacts and image distortion. Here, we present the novel application of DW-FSE-PROPELLER in in-vivo imaging of mice at 9.4T.

                  1805.     K-Space Weighted Multi-Channel Regularization for Motion Correction in Multi-Shot DWI

Sheng Fang1, Kui Ying1

1Tsinghua University, Beijing, People's Republic of China

Multi-shot diffusion-weighted imaging suffers from motion-induced phase error that varies from shot to shot. Conjugate-gradient (CG) based reconstruction may not adequately correct this error if phase estimation is not accurate enough. Besides, the CG algorithm only utilizes the phase information from the navigator image. In this work, we propose an effective k-space weighted multi-channel regularization algorithm based on Tikhonov regularization to fully utilize acquired navigator data and further reduce the residual motion-induced aliasing artifacts left by standard Tikhonov regularization. Both single-coil and multi-coil simulations have been performed to demonstrate the feasibility of the proposed method.

                  1806.     Multi-Slice High Resolution Cerebellum Diffusion Tensor Imaging Using Pre-IR Inner Volume Excitation

Tzu-Cheng Chao1, Yi-Jui Liu2, Teng-Yi Huang3, Hsiao-Wen Chung1, Cheng-Yu Sandy Chen4

1National Taiwan University, Taipei, Taiwan; 2Feng-Chia University, Taichung, Taiwan; 3National Taiwan University of Science and Technology, Taipei, Taiwan; 4Tri-Service General Hospital, Taipei, Taiwan

Susceptibility-induced geometric distortions in diffusion tensor EPI limit the image resolution in regions showing strongly inhomogeneous magnetic fields. In this work, we proposed an alternative inner volume excitation scheme for EPI with reduced FOV, which employed a pre-inversion approach suitable for multi-slice acquisition without severe compromise in SNR. Simulations and experimental results for diffusion tensor imaging in the cerebellum showed that this approach could provide simultaneous signal uniformity and good SNR throughout all slices. Susceptibility-related distortions were effectively minimized via a shortening of the data acquisition window to achieved DTI of the cerebellum at 0.86mm in-plane resolution.

                  1807.     Comparison of Sequences for Improved Diffusion Weighted Imaging at 7 T

Paul S. Morgan1, Ron J. Coxon1, Josef Habib1, Penny A. Gowland1, Richard Bowtell1

1University of Nottingham, Nottingham, UK

Application of diffusion-weighted (DW) MRI on a 7 T scanner holds the promise of significantly increased spatial resolution. However the challenges involved in implementing DW-EPI at 7 T require re-evaluation of the best sequence for obtaining DW images. Here we have therefore implemented four different DW-EPI sequences at 7 T and compared the results in terms of signal-to-noise and spatial distortion, as well as studying the effect of parallel imaging. Twice-refocused DW-EPI acquisitions were found to offer the best compromise between SNR and spatial distortion.

                  1808.     Comparison of Short-Readout Trajectories for Diffusion-Weighted Imaging

Samantha J. Holdsworth1, Stefan Skare1, Rexford D. Newbould1, Anders Nordell2, Roland Bammer1

1Stanford University, Palo Alto, California , USA; 2Karolinska University Hospital, Stockholm, Sweden

“Short-Axis readout Propeller EPI” (SAP-EPI), its dual-blade variant (dual-blade SAP-EPI), and Readout-Segmented EPI (RS-EPI) have been proposed as variants of EPI for high resolution diffusion-weighted (DW) imaging. While there are many similarities between these sequences, there are various differences between them which affect the scan efficiency and overall image quality. The purpose of this abstract is to make an initial assessment of these schemes with regard to diffusion preparation/acquisition ratio, normalized scan time, and image quality for a typical set of scan parameters we have been using for high resolution GRAPPA-accelerated DW imaging.

                  1809.     Non-Uniform Distribution of Diffusion Gradient Directions Using Preferred Diffusion Tensor Orientations
                                in the Human Brain

Jeroen Siero1, Hans Hoogduin1

1University Medical Center Groningen / University of Groningen, Groningen, Netherlands

A non-uniform gradient direction scheme for DTI is presented based on the non-uniform fiber orientations in the human brain. A comparison with a uniform 60 direction scheme shows an increase in FA values and a decreased error for the dominant fiber directions.

                  1810.     On the Utility of Complex-Averaged Diffusion-Weighted Images  [Not Available]

Rexford David Newbould1, Stefan Skare1, Roland Bammer1

1Stanford University, Stanford, California , USA

Magnitude averaging is very common in diffusion imaging, as it avoids random phase offsets in the data from the diffusion-sensitizing gradients. Noise in magnitude MR images is Rician distributed. In low SNR magnitude images, such as diffusion images, the Rician distribution approaches a Rayleigh distribution.  This introduces a severe non-zero bias of the signal expectation value and underestimates the calculated ADC. The deflection of the diffusion attenuation can reduce the CNR and mimic biexponential decay. Combining magnitude diffusion images for signal averaging or to create isotropic DWI images does not lower this mean, whereas combining complex diffusion images does.

                  1811.     High Angular Resolution Diffusion Imaging with B0 Distortion Correction at 7T

Ha-Kyu Jeong1, 2, Adam W. Anderson1

1Vanderbilt University, Nashville, Tennessee, USA

In this study, high angular resolution diffusion imaging (HARDI) measurements performed at 7T were corrected for distortions due to B0 field inhomogeneities using a static field map. After the correction, the anatomy of individual brain slices and corresponding fiber tracts are much closer to those of multishot gradient echo images, which have relatively small distortions. The improvements in spatial accuracy of the HARDI data are critical for quantitative applications of diffusion MRI at high field strengths.

                  1812.     In Vivo Human Brain Diffusion Tensor Imaging (DTI) at 3T and 7 T

Ralf Luetzkendorf1, Tobias Moench1, Maurice Hollmann1, Sebastian Baecke1, Claus Tempelmann1, Joerg Stadler2, Johannes Bernarding1

1University of Magdeburg, Magdeburg, Germany; 2Leibniz Institute for Neurobiology, Magdeburg, Germany

Higher B0 fields are expected to increase the signal-to-noise ratio which should lead to higher spatial resolution of DTI. At high fields B1 inhomogeneities are strong and result in sever distortions and signal voids in DTI. We used parallel imaging techniques combined with data post-processing to reduce distortions and to reach a high spatial resolution. The same starting maps and waypoint maps to track the apparent fibers of the same volunteer were used in both 3T and 7T to ensure the comparability of the data.

                  1813.     Fast Fluid Suppressed DTI

Allen W. Song1, Zoe Englander1, Bin Chen1

1Duke University, Durham, North Carolina, USA

DTI images suffer from fluid contaminations from CSF and vasculature, especially in the ventral brain regions, periventricular space and cortical surface, because of the hyper-intensity of fluid in the T2 weighted baseline image. Early methods for removing these confounds have relied on inversion recovery technique which could result in a large reduction in signal-to-noise ratio and temporal resolution. Here we propose a method that applies flow-sensitive diffusion weighting to the baseline scan, and evaluate its advantage on improving the delineation of white matter anisotropy. Much improved characterization of white matter anisotropy is found with further separation from the gray matter.

                  1814.     Compressed Sensing in Diffusion-Weighted Radial-FSE

Ted P. Trouard1, 2, John Wade Totenhagen1, Ali Bilgin1

1University of Arizona, Tucson, Arizona , USA

Compressed Sensing (CS) reconstruction enables generation of images from dramatically undersampled MRI data.  In this work, CS methodology is applied to undersampled diffusion-weighted radial-FSE datasets to evaluate the utility of CS to reduce scan times in multishot DW-radial-FSE acquisitions.  DW-radial-FSE has been shown to produce diffusion-weighted images with high spatial resolution and little artifact from motion and/or magnetic field inhomogeneities, but requires considerably more acquisition time than single-shot DW-MRI methods.  CS reconstruction of severely undersampled radial-FSE data is shown to produce diffusion-weighted images and ADC maps without the streaking artifacts generated by filtered backprojection or regridding reconstruction.

                  1815.     In Vivo Diffusion Tensor Imaging of Human Optic Nerve Using 2D Interleaved Inner Volume Technique
                                on 3T System

Seong-Eun Kim1, Eun-Kee Jeong1, Tae Ho Kim1, J Rock Hadley1, Emilee Minagla1, Jeff Anderson1, Dennis L. Parker1

1University of Utah, Salt Lake City, USA

In this work we present the in vivo DTI measurement of the normal human optic nerve using two different interleaved multiple inner volume diffusion weighted EPI sequences and a 20 channel dedicated optic nerve coil on 3T system. The results indicate that both 2D IMIV-DWEPI and 2D rFOV-DWEPI allow reliable DTI measurement of optic nerve and ocular muscle. Quantitative analysis of diffusivity and anisotropy in the human optic nerve area appears to be feasible and has potential to enable more sensitive and specific detection and monitoring of structural changes caused by pathology including multiple sclerosis, optic neuritis, and neurofibromatosis.

                  1816.     A Simple But Robust Isotropic and Background Gradient Independent Diffusion Gradient Design

Hua Guo1, 2, Allen W. Song2, Ed X. Wu1

1The University of Hong Kong, Pokfulam, Hong Kong; 2Duke University, Durham, North Carolina, USA

Due to computation and design complexity, there is no design so far for isotropic and background gradient independent diffusion gradients. In this abstract, we present a simple but robust method to design orientation invariant and background magnetic field insensitive diffusion gradients. Although the diffusion weighting efficiency is reduced, this design provides a set of diffusion gradients that may be used to map ADC efficiently and accurately or in presence of severe field inhomogeneity such as induced by metal implants.

                  1817.     DTI of the Human Brain with Sub-Millimeter Voxel Size: Clear Depiction of Fiber Decussation in the
                                Optic Chiasm

Joelle E. Sarlls1, Stefano Marenco1, Carlo Pierpaoli1

1National Institutes of Health, Bethesda, Maryland, USA

Sub-millimeter isotropic voxel diffusion tensor images (DTI) of the optic chiasm are presented, in vivo, for the first time. Data are acquired with a modified radial-FSE sequence, which allows anatomical details of structures in the brain to be studied  with a voxel size about 10 times smaller than that currently achievable with EPI-based DTI. These images clearly depict the decussation of the medial fibers in the optic chiasm. Geometric distortion and susceptibility artifacts are virtually eliminated in these high-resolution DTI maps.


Diffusion & Perfusion Studies in Animal Models

Hall D                                   Thursday 13:30-15:30                                                                                                                                           

                   1867.     Rapid High-Field Diffusion MR Histology: Image-Based Phase Correction for Diffusion-Weighted RARE

Julian Michael Tyszka1, Lawrence R. Frank

1California Institute of Technology, Pasadena, California , USA

Two phase correction schemes for eddy-current ghosting in high-field diffusion-weighted RARE imaging are presented. The schemes are tailored for efficient MR diffusion histological studies of samples such as fixed rodent brains, in which physiological motion is absent and per-acquisition navigation can be eliminated. The effectiveness of both approaches is demonstrated in rat brain samples.

                  1868.     Altered Fiber Connectivity in Adult Brain of PAX6 Knock-Out Mice Revealed by DTI in Vivo

Susann Boretius1, Anastassia Stoykova1, Roland Tammer1, 2, Jens Frahm1, Thomas Michaelis1

1Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany; 2DFG Center of Molecular Physiology of the Brain (CMPB), Göttingen, Germany

Cortex specific conditional knock-out of transcription factor PAX6 at the beginning of neurogenesis in mice results in almost full abolishment of the upper cortical layers. To assess putative structural abnormalities in the cortex at maturity, pairs of mutant and control mice were studied by diffusion tensor imaging (DTI). Tracking of major neuronal fiber bundles revealed a lack of interhemispheric connectivity as well as pronounced fiber reorganization in the septal region and fimbria. These findings indicate an important role of PAX6 in establishment of the intracortical fiber connectivity. 

                  1869.     Quantifying Cerebral Blood Volume Over the Mouse Cerebral Cortex Using Micro-CT Co-Registered
                                to an MRI Anatomical Atlas

Brige P. Chugh1, Jason P. Lerch1, Lisa X. Yu1, R Mark Henkelman1, John G. Sled1

1Mouse Imaging Centre,Toronto Centre for Phenogenomics, Hospital for Sick Children, Toronto, Canada

Measurement of the cerebral blood volume (CBV) in local regions of the mouse brain will be useful to describe the phenotypes of models of neurodegenerative diseases that alter microvasculature including Alzheimer’s disease. A limitation of current methods to determine CBV in mice, including MRI methods sensitive to magnetic susceptibility changes, is that they do not provide absolute quantification of CBV over the entire mouse cerebral cortex. To overcome this difficulty, we developed a method to determine absolute CBV over the mouse cortex using micro-computed tomography (micro-CT) co-registered to an MRI anatomical brain atlas.

                  1870.     Diffusion Tensor Imaging Detects and Characterizes Proliferative Diabetic Retinopathy in the
                                 Murine Retina

Saurav Chandra1, Angelos Barmpoutis1, John Forder1

1University of Florida, Gainesville, USA

The specific aim in this study is to prove that the alterations in the eye following damage (by laser damage and diabetic retinopathy) can be detected by DTI. This is done by comparing the fractional anisotropies in the retinas of controls versus diabetic eyes. The mice had been subjected to Type I diabetes. The experiments were successful in determining significant differences between the fractional anisotropies of retinas in controls compared to the lasered as well as diabetic retinas. Future studies will involve in vivo imaging of mice with various stages of the disease.

                  1871.     In Vivo Quantification of Lamina T1, T2, and Apparent Diffusion Coefficient in the Mouse Retina at 11.74T

Junjie Chen1, Qing Wang1, Huiying Zhang1, Xiaoxia Yang1, Jian Wang2, Bruce A. Berkowitz3, Samuel A. Wickline1, Sheng-Kwei Song1

1Washington University, St. Louis, Missouri, USA; 2Chinese Pharmaceutical Association, Beijing, People's Republic of China; 3Wayne State University, Detroit, Michigan, USA

Quantitative MRI of the mouse retina (~ 250 µm thick) is challenging due to its limited thickness.  In the present study, T1 and T2 relaxation time constants, and the directional apparent diffusion coefficient (ADC) in three MR-detected retina layers of C57/BL6 mice were measured at 47 x 47 x 400 µm 3 resolution.  This study establishes, for the first time, normative metrics of T1, T2, and ADC of the mouse retina. These MR parameters are expected to be useful in future evaluation of developmental and pathological alterations of retinal cell layers in mice. 

                  1872.     Blood-Flow MRI of Retinal Degeneration

Yingxia Li1, Haiying Cheng1, Qiang Shen1, Moon K. Kim2, Darin E. Olson1, Peter M. Thule1, Machelle T. Pardue2, Timothy Quyen Duong1

1Emory University, Atlanta, Georgia, USA; 2Department of Veterans Affairs Medical Center, Atlanta, Georgia, USA

Vision loss due to retinal degeneration is a major problem in clinical ophthalmology. We have previously reported a thinning of the retina and perturbed BOLD fMRI responses to physiologic challenges in the retina of an animal model of progressive retinal degeneration (Royal-College-of-Surgeons rats). In this study, we extend previous findings by studying basal blood flow (BF) and physiologically induced BF changes in RCS rat retinas and age-matched controls at 90x90x1500-ƒÝm. Quantitative BF was measured using the continuous arterial-spin-labeling technique. MRI provides quantitative BF data without depth limitation and large field-of-view and could complement existing retinal imaging techniques.

                  1873.     Quantification of Perfusion and Blood Volume in the Brains of Rats Breathing Carbogen Using ASL and
                                a Two Compartment Model

John Carr1, David Buckley1, Jean Tessier2, Geoff Parker1

1University of Manchester, Manchester, UK; 2AstraZeneca, Macclesfield, UK

ASL is shown to be a feasible method for measuring F in a subcutaneous tumour model and sensitive enough to quantify changes resulting from carbogen breathing. A positive correlation is shown between T2* change and F change due to carbogen (r = 0.68, p = 0.01) and between ADC and F (r = 0.67, p =0.04). No correlation was found between IAUC and F indicating IAUC measurements are dominated by CA leakage. In summary, a novel application of the ASL technique is demonstrated showing how ASL can be used in tumours outside the brain in animals and potentially in humans.

                  1874.     Arterial Spin Labeling Quantification of Cerebral Blood Flow and Cerebrovascular Reactivity to Carbon
                                Dioxide in Normotensive and Hypertensive Rats: A Comparative Study

Fernando F. Paiva1, 2, Erica C. Henning1, Alberto Tannus2, Afonso C. Silva1

1National Institutes of Health, Bethesda, Maryland, USA; 2Universidade de Sao Paulo, Sao Carlos, Brazil

Cerebral blood flow under basal and hypercapnic condition (5% and 10% CO2) were obtained in normotensive and hypertensive rats using a continuous ASL EPI sequence with a a three coil system comprised of a homogeneous volume excitation coil, a receive-only quadrature surface coil and a dedicated labeling RF coil. Higher CBF values were found in hypertensive rats both under normocapnia and hypercapnia. While the vascular reactivity under 5% carbon dioxide was not significantly different amongst both strains, the hypertensive rats displayed impaired reactivity when submitted to 10% CO2.

                  1875.     Dynamic Arterial Spin Labeling Functional MRI (DASL-FMRI)

Fernando F. Paiva1, Bojana Stefanovic1, Yoshiyuki Hirano1, Alberto Tannus2, Afonso C. Silva1

1National Institutes of Health, Bethesda, Maryland, USA; 2Universidade de Sao Paulo, Sao Carlos, Brazil

Dynamic arterial spin labeling (DASL) is an efficient way to quantitatively measure cerebral blood flow (CBF), the transit-time tƒnof the endogenous labeled arterial water and T1 of the brain. In this work, we combine DASL with fMRI experiments during somatosensory stimulation in rats. We show that the combination of DASL with fMRI constitutes an interesting approach to obtain, in a single experiment, dynamic quantification of both resting and functional hemodynamics with improved efficiency and SNR. This new methodology is poised to become a versatile experimental plat-form for studying the spatial and temporal characteristics of functional cerebral hemodynamics.

                  1876.     Agonists of Alpha2-Adrenoceptors and Imidazoline Receptors Show Selectivity-Related Differential Effects
                                on Cerebral Blood Flow in Rat: An MR Perfusion Imaging Study

Xiao-xia Du1, Fu-chun Lin2, Hao Lei1

1Wuhan Institute of Physics and Mathematics, Chinese Academy of Science, Wuhan, People's Republic of China; 2 Wuhan Institute of Physics and Mathematics, Chinese Academy of Science, Wuhan, People's Republic of China

Agonists/antagnoists of alpha2-adrenoceptor and imidazoline receptor are known to have the ability to affect cerebral blood flow (CBF). Xylazine, clonidine and moxonidine have different receptor affinities for alpha2-adrenoceptors and imidazoline receptors. In this study, continuous arterial labeling (CASL) perfusion imaging was used to investigate the effects of xylazine, clonidne and moxonidine on CBF in rats. The results showed that, at the dosages used, the three drugs induced similar cardiovascular responses, but significantly different effects on CBF.

                  1877.     Insulin Reverses Attenuation of Cerebral Blood Flow (CBF) Caused by Hyperglycemia in a Mouse Model
                                of Diabetes: Potential Impact on Acute Ischemic Stroke

Samir Kamalesh Amin1, Faridis Serrano1, Tomoya Terashima1, Lawrence Chan1, Lingyun Hu1, Robia G. Pautler1

1Baylor College of Medicine, Houston, Texas, USA

Diabetes is associated with microvascular disease and believed to increase cerebrovascular complications, particularly acute ischemic strokes. Studies have shown that both acute and chronic hyperglycemia cause cerebral blood flow (CBF) reduction, however, little is known about the mechanism of change. We used an in vivo mouse model of diabetes not only to evidence reduced CBF utilizing Flow-sensitive Alternating Inversion Recovery (FAIR) arterial spin labeling (ASL), but also to determine if this vascular effect is reversible by modifying glucose levels with insulin. In conclusion, we observed CBF reduction in a diabetic mouse model (STZ) and witnessed an “insulin rescue” in CBF.

                  1878.     High-Field MRI Detection of Magnevist Permeation Into Normal Mouse Brain Parenchymal and Ventricular

Martin M. Pike1, 2, William D. Rooney2, Xin Li2, Christine Neumann Stoops1, G Yancey Gillespie1, Charles S. Springer2

1University of Alabama at Birmingham, Birmingham, USA; 2Oregon Health & Science University, Portland, USA

Recent evidence suggests that contrast agent (CA) permeation into normal brain parenchyma is detectable with high-field MRI, which should increase detection sensitivity via tissue 1H2O T1 increases, concomitant with greater CA-induced T1 reductions.  During gradual, sustained GdDTPA2- infusions, we observed substantial image intensity increases in the normal mouse brain ventricular system, and in non-ventricular parenchyma, using ultra high-field MRI (8.5T).   These data provide clear and convincing evidence of standard monomeric Gd(III) chelate MRI CA permeation into normal brain parenchyma, consistent with improved  CA detection sensitivity at high-field,  potentially enabling implementation of powerful new CA approaches in normal and diseased brain.

                  1879.     Cerebral Blood Volume Alterations After Traumatic Brain Injury in the Rat Brain - 2 Weeks MRI Follow-Up

Riikka Johanna Immonen1, Juha Yrjänheikki2, Taneli Heikkinen2, Leena Tähtivaara2, J Puoliväli2, R I. Grundy3, T Tuinstra4, A Phinney4, B Van Vliet4, Olli Gröhn1

1A.I.Virtanen Institute for Molecular Sciences, University of Kuopio, Kuopio, Finland; 2Cerebricon Ltd., Kuopio, Finland; 3Cerebricon Ltd., London, UK; 4Solvay Pharmaceuticals BV, CP Weesp, Netherlands

Hypoperfusion may have a role in the secondary injury cascade following traumatic brain injury. We measured relative cerebral blood volume (CBV) changes and diffusion in rat brain following cortical impact injury aiming to find out more about the hemodynamics in the perifocal area surrounding the lesion. The Δ R2 and Δ;R2* maps using iron oxide contrast agent and average diffusion maps were acquired at 1h, 2h, 4h, 1d, 2d, 3d, 4d, 7d and 14d after TBI. Both Δ R2 and Δ;R2* showed acute drop in CBV in the perifocal area, which then started to recover. Yet even after 14d, ΔR2 remained decreased.

                  1880.     Velocity Selective Arterial Spin Labeling in Rat Brain

Kim C.C. van de Ven1, Rick M. Dijkhuizen1, Ivo A.C.W. Tiebosch1, Annette Van der Toorn1

1University Medical Center Utrecht, Utrecht, Netherlands

Velocity Selective Arterial Spin Labeling (VSASL) is an ASL-based perfusion MRI technique that magnetically labels blood spins based ontheir velocity instead of their spatial position. Thus far VSASL perfusionimaging has not yet been assessed for application in an animal model. We measured VSASL subtraction signal in in vivo rat brain at 9.4T, which diminished to noise level after asphyxiation. Our study demonstrates that VSASL can be successfully applied in rat brain studies.

                  1881.     Automatic Analysis of Quantitative Cerebral Perfusion in Rodents

Rui Liu1, Ping Hou2, Kurt H. Bockhorst2, Renjie He2, Ponnada A. Narayana2

1University of Houston, Houston, Texas, USA; 2University of Texas Medical School at Houston, Houston, Texas, USA

Synopsis: A method for automatic determination of the perfusion parameters based on dynamic susceptibility contrast MRI is proposed and applied to determine the hemodynamic parameters. Our algorithm is based on the singular valued decomposition (SVD) technique in which the thresholds are automatically determined. In addition, our algorithm automatically determines the arterial input function by searching the whole image volume. Application of this method to rodents yielded a value of the cerebral blood volume that is very close to the value determined using the microsphere technique, considered to be the “gold standard”.


Animal Models & Cerebral Ischemia

Hall D                                   Thursday 13:30-15:30                                                                                                                                           

                  1933.     Longitudinal MRI for the Detection of a Typical Pattern of Cerebral Blood Flow (CBF) and Tissue
                                 Integrity Changes After Stroke in Ischemia Tolerant Rats

Susanne Wegener1, Tommy Shute1, Eric C. Wong1

1University of California San Diego, La Jolla, USA

One of the unresolved problems in stroke therapy is the heterogeneity of the disease and of the individual resistance to ischemic damage. We used longitudinal MRI to study ischemia tolerance, induced in rats by preconditioning with 3-nitroproprionic acid (3NPA). When preconditioned rats were subjected to transient ischemia, the immediate deficit on apparent diffusion coefficient maps was dramatically reduced within 30min of occlusion, together with better maintained residual blood flow (CBF) in the ischemic area compared to controls. Besides, CBF was lower on the unaffected side in NPA animals. MRI might have the potential to detect a “signature” of ischemia tolerance.

                  1934.     The Relationship Between Perfusion and Diffusion Imaging Parameters in Ischemic Stroke

Qiang Shen1, Meghana Bhatta1, Ryan Jessee1, Timothy Q. Duong1

1Emory Unviersity, Atlanta, Georgia, USA

Ischemic stroke occurs when cerebral blood flow (CBF) falls below a critical threshold, resulting in energy failure which subsequently manifests into a reduction in the water apparent diffusion coefficient (ADC). However, how the ADC is affected by CBF over time and under different ischemic conditions remains poorly understood. In this study, ADC and CBF in rat models following permanent and transient (30-min, 60-min and 90-min) MCAO were systematically studied at multiple time points after stroke. These results provide novel insight into the relationship between ADC and CBF under different ischemic durations and time after stroke.

                  1935.     Postischemic Hyperperfusion: The Insight from a Multi-Parameter MRI Study

Qiang Shen1, Hanh Nguyen1, Timothy Q. Duong1

1Emory Unviersity, Atlanta, Georgia, USA

We investigated postischemic hyperperfusion in rats subjected to three different occlusion durations. Diffusion, perfusion and T2 imaging during acute and sub-acute phase were acquired. Hyperperfusion was observed predominantly in the core after 24 hrs post-occlusion in the 30-min MCAO group, some in the 60-min group, and none in the 90-min group. No hyperperfusion was observed in normal tissues. Tracking tissue fates indicates that subsequently salvaged tissue has normal CBF (no hyperperfusion) whereas tissue destined to infarct showed hyperperfusion. These results suggest that chronic phase hyperperfusion is due to changes in blood-brain permeability which leads to increased CBF in infarct regions.

                  1936.     Effects of Blood-Brain Permeability on CBF Measured by Arterial Spin Labeling and Dynamic Susceptibility

Yoji Tanaka1, Tsukasa Nagaoka1, Govind Nair1, Timothy Q. Duong1

1Emory University, Atlanta, Georgia, USA

Stroke disrupts blood brain barrier, resulting in changing vascular permeability which is expected to affect cerebral blood flow (CBF) quantification. However, permeability changes are generally not taken into account in perfusion imaging of stroke. The aim of this study is to examine how changes in permeability affect CBF measured by arterial-spin-labeling and dynamic-susceptibility-contrast MRI on the same animals under different experimental conditions which included stroke, hypercapnia and permeability disruption by mannitol. We concluded that permeability changes markedly affects the CBF, it affects the two methods very differently, and CBF MRI of stroke needs to take permeability changes into account.

                  1937.     Comparison of Ischaemic Lesion Evolution Using Diffusion and Perfusion Imaging in the Shrsp RAT and
                                 WKY RAT Following Permanent Middle Cerebral Artery Occlussion (MCAO)

Chris McCabe1, William Matthew Holmes1, Lindsay Gallagher1, Willy Gsell2, Anna F. Dominiczak1, Barrie Condon1, I Mhairi Macrae1

1University of Glasgow, Glasgow, UK; 2Imperial College London, London, UK

In the present study we investigated the spatiotemporal evolution of stroke in the SHRSP rat and compared this to its normotensive control the WKY rat.  We have demonstrated that the SHRSP rat has significantly less penumbral tissue than the WKY within 1 hour of stroke onset and by 6 hours the SHRSP has no diffusion/perfusion mismatch.  These results could have important implications for the management of stroke patients with pre-existing hypertension and suggest  ischaemic damage could  progress at a faster rate in the presence of known risk factors such as hypertension.

                  1938.     Differential Spatio-Temporal Cerebral Blood Volume Response to Normobaric Oxygen Therapy in an
                                Experimental Rat Stroke Model

Ona Wu1, Jie Lu1, Yasu Egi1, Guangping Dai1, Yoshi Murata1, Joseph B. Mandeville1, John J. Marota1, A Gregory Sorensen1, Rick M. Dijkhuizen2, Kenneth K. Kwong1, Eng H. Lo1, Aneesh Singhal3

1Massachusetts General Hospital, Charlestown, Massachusetts, USA; 2University Medical Center Utrecht, Utrecht, Netherlands; 3Massachusetts General Hospital, Boston, Massachusetts, USA

In rodent and pilot human acute stroke studies, normobaric oxygen therapy (NBO, or inhaled 100% oxygen) transiently improved neurological deficits and diffusion-weighted imaging abnormalities. We used serial MRI in rodent stroke models to investigate the hemodynamic effects of NBO in different brain regions. NBO induced an early, reproducible change in cerebral blood volume Δ CBV) in different brain regions, with ‘salvageable’ tissue showing increased CBV. This effect diminished over 3 hours. Whether this effect indicates a mechanism (e.g a hemodynamic “reverse steal phenomenon”) or a consequence of ‘salvaged’ tissue requires further investigation.

                  1939.     Vasculature Changes Early After Stroke Using One-Hour MCAo Mouse Model at 9.4T  [Not Available]

Shuning Huang1, Dmitriy Atochin2, Guangping Dai2, Paul Huang2, Bruce R. Rosen2, Young Ro Kim2

1MIT/MGH, Cambridge, Massachusetts, USA; 2MGH, Charlestown, Massachusetts, USA

Restoration of cerebral blood supply at early stage of stroke is critical for salvaging brain tissues at risk. We characterized vascular transformation during the reperfusion phase of transient ischemia using steady-state intravascular contrast agent techniques. Previous studies have shown that relative cerebral blood volume (rCBV) measured from Δ R2 and Δ R2*, the transverse relaxation rate change before and after the contrast agent administration, reflects total and micro-vascular CBV. The goal of this study was to understand cerebrovascular changes (rCBV and vessel size) in transient stroke mouse models using an intravascular contrast agent (superparamagnetic iron oxide nanoparticles) at 9.4T.

                  1940.     Diffusion and Extracellular Space Volume in the Rat Somatosensory Cortex During Recovery from
                                Transient Global Ischemia/hypoxia

Ivan Vorisek1, 2, Norbert Zoremba3, Ales Homola1, 2, Karel Slais1, 2, Eva Sykova1, 2

1Institute of Experimental Medicine ASCR, Prague, Czech Republic; 2Charles University, 2nd Medical Faculty, Prague, Czech Republic; 3University Hospital RWTH Aachen, Aachen, Germany

The aim of the present study was to quantify the changes in ECS diffusion parameters during recovery from transient ischemia by TMA+-diffusion and MRI measurements and to describe their time course. The data were correlated with the results of DC-potential recordings and measurements of extracellular potassium levels. To the best of our knowledge, the diffusion parameters of the ECS during recovery from transient ischemia have not yet been studied in vivo.

                  1941.     MRI/MRS of Ischemic Evolution in Mouse Brain at 14.1 T  [Not Available]

Hongxia Lei1, 2, Carole Berthet3, Lorenz Hirt3, Rolf Gruetter1, 4

1Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland; 2University of Lausanne, Lausanne, Switzerland; 3Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland; 4University of Geneva, Lausanne, Switzerland

High magnetic fields increase sensitivities and thus using a recently installed 14.1 T/26cm MR system, we sought to determine the feasibility of studying lesion developing and neurochemical changes following 30 min of ischemia in mouse brain. At 8 and 24h after the insult, T2-weighted images presented lesion developing and localized spectra were obtained with 0.035ppm linewidths in the stroke region after B0 homogenneities adjustment with 2nd-order shimming. Prominent changes include a transient doubling of brain Gln, postulated to reflect Glu excitotoxicity, and decreases in several compounds such as NAA, Glu, Tau, as well as increases in acetate (attributed to NAA breakdown) and Lactate.

                  1942.     Radiation Pretreatment Result in a Dramatic Increase in ADC After Ischemic Brain Injury in Rats

Elena Titova1, Arash Adami1, Robert Ostrowski1, Serafin Lalas1, Roman Vlkolinsky1, John H. Zhang1, Gregory Nelson1, Andre Obenaus1

1Loma Linda University School of Medicine, Loma Linda, California , USA

Radiation is routinely used in general medical practice significantly increases risk of stroke among patients but the response of the brain after such kind of injury is still insufficiently studied. We report that a single radiation (8Gy) exposure at 10 days prior to middle cerebral artery occlusion appears to reduce cytotoxic edema but dramatically increased ADC values at later time points. Thus, stroke outcomes in previously irradiated patients differ from the normal population and relatively low doses of radiation result in less brain edema in acute stages.

                  1943.     White Matter Injury in Neonatal Rats After a Mild Cerebral Hypoxic- Ischemic Insult: MR Confirmation
                                Prior to Assessment of Injury Markers
 [Not Available]

Ursula I. Tuor1, 2, Min Qiao1, Sanju Lama2, Salma Shivji2, Kumud Deka2, Tadek Foniok1

1National Research Council - Institute for Biodiagnostics (West), Calgary, Canada; 2University of Calgary, Calgary, Canada

We hypothesized that mild cerebral hypoxia-ischemia producing selective white matter injury would have accompanying markers of injury in white matter reflecting mechanisms of damage.  T2 MRI was used in our mild model of cerebral hypoxia-ischemia to screen animals with relatively selective white matter injury.  In such animals, substantial white matter injury appeared irreversible as demonstrated by an increased labelling of cells with TUNEL and a reduced myelination detected with O4 and MBP.  Inflammatory responses associated with microglia activation (ED1) were observed selectively in the whiter matter at 48hrs post a mild hypoxia ischemia.

                  1944.     Effect of Gender on Cerebral Hypoxic-Ischemic Injury in Neonatal Brain:  a Magnetic Resonance Imaging
 [Not Available]

Sanju Lama1, 2, Min Qiao2, Tadek Foniok2, Ursula I. Tuor, 12

1University of Calgary, Calgary, Canada; 2National Research Council Institute for Biodiagnostics (West), Calgary, Canada

In adults, stroke injury is affected by gender.  We hypothesized that neonates  would also exhibit gender-differences in the extent, distribution or degree of vasogenic edema detected with MRI following cerebral hypoxia-ischemia.  Seven day old rats were subjected to cerebal hypoxia-ischemia and T2 imaging to determine infarct size and edema.  Three days post insult, the ischemic lesion volume was similar in male and female pups, however, T2 values in ischemic parietal cortex were less in female than male rat pups.  The greater edema in males supports a sexual dimorphism regarding the mechanisms of hypoxic-ischemic injury in immature brain.

                  1945.     Cerebral Reorganization After Transient Focal Ischemia in Developing Rat Brain

Chrystelle Po1, Sebastien Fau2, Christiane Charriaut-Marlangue2, Philippe Meric1, Brigitte Gillet1

1ICSN/CNRS, Gif-sur-Yvette, France; 2UMR-CNRS 7102, Paris, France

The evolution of the injured tissues after a transient focal cerebral ischemia in neonate rats was investigated by serial measurements of T2 maps and DTI. Since day 7 after ischemia up to day 21, a significant low T2 value area on T2 maps and significant perturbations of tissue organization evidenced on maps of anisotropy fraction and of first eigenvector of DTI appeared in the previously ischemic area. At day 21, this area correlated with a significant increase of cell density on corresponding cresyl-violet stained brain slices suggesting that these data reflect tissue healing processes such as gliosis.

                  1946.     Tissue Water Dynamics in Acute Ischemic Stroke by T and T MRI Using Adiabatic Pulses  [Not Available]

Kimmo Jokivarsi1, Juha-Pekka Niskanen1, 2, Heidi Gröhn3, Shalom Michaeli4, Michael Garwood4, Risto A. Kauppinen5, Olli H. Gröhn1

1A.I.Virtanen Institute for Molecular Sciences, Kuopio, Finland; 2University of Kuopio, Kuopio, Finland; 3Kuopio University Hospital, Kuopio, Finland; 4University of Minnesota, Minneapolis, Minnesota, USA; 5Dartmouth Medical School, Hanover, New Hampshire, USA

Rotating frame relaxation obtained with adiabatic pulses allows for the contribution of dipolar interactions and exchange effects to be modulated by changing amplitude and phase modulation of the RF pulses. Using a known two-site exchange model the inherent correlation times, population sizes and exchange correlation times can be computed.  We investigated the water dynamics during evolving cerebral ischemia in a rat permanent stroke model. Our results show that both adiabatic T1 ρ and T2 ρ MRI reveal cerebral ischemia early on. Changes in fitted exchange parameters are indicative of increase in free water content and lytic damage to tissue.

                  1947.     Differentiating the Early Stage Ischemic Stroke Severity in Mice Using Diffusion Tensor Imaging

Tzy-Haw Wu1, 2, Hsiao-Fang Liang2, Chin-I Chen, 23, Chung-Yi Hsu4, Sheng-Kwei Song2

1National Taiwan University Hospital, Taipei, Taiwan; 2Washington University School of Medicine, St. Louis, Missouri, USA; 3Taipei Medical University - Wanfang Municipal Hospital, Taipei, Taiwan; 4Graduate Institute of Neuroscience, Taipei Medical University, Taipei, Taiwan

SynopsisWe generated a mouse stroke model to determine if DTI can differentiate the different severities of ischemic stoke in the early stage. In this study, the areas of infarcted cortex and external capsule (EC) were evaluated by DTI. The result showed that axial diffusivity and radial diffusivity in the area of infarcted EC are statistically different among the three ischemic stroke groups of different severities. The infarcted cortex volume increases with the increased severity of stroke. ADC values in the infarcted cortex are not as sensitive as axial diffusivity or radial diffusivity in the area of infarcted EC. The DTI predicted axonal injury in EC was also validated by immunohistochemistry. In conclusion, DTI provides a good quantitative measure to evaluate the severity of early stage ischemic stroke in mice, especially the measurement in the area of infarcted EC.


Alzheimer's Disease & Mild Cognitive Impairment

Hall D                                   Thursday 13:30-15:30                                                                                                                                           

                  2008.     Diffusion Tensor Imaging and Voxel-Based Morphometry Study in Mild Alzheimer's Disease

Qin Chen1, Ling Zou, Qiang Yuan1, Zheng-Yan Li, Luo Ou-Yang, Wei-Wei Zhang, Li-Jun Jiang, Dong Zhou1, Qi-Yong Gong

1West China Hospital of Sichuan University, Chengdu, People's Republic of China

Despite many efforts to draw a clear cut picture of the disease, a comprehensive characterization of grey and whiter matter changes in mild Alzheimer's disease (AD) is still not available. In this study, we aimed to characterize the brain changes in mild AD by the combined used of VBM and DTI. Our results suggest atrophy of cortical and subcortical structures and nerurodegeneration of specific fibre tracts may contribute to neurological deficits in AD. This approach guide future research investigating the relation between the brain areas involved and the clinical features in different phases of the disease.

                  2009.     DTI Measures at the Midline Corpus Callosum in Patients with Incipient and Mild Alzheimer¢s Disease

Julio Acosta-Cabronero1, Guy B. Williams1, Peter J. Nestor1

1University of Cambridge, Cambridge, UK

The corpus callosum (CC), which contains millions of inter-hemispheric axons, is known to become atrophic early in AD, and its integrity is assumed to be associated with global cognitive performance. In this study, we extracted several DTI measures at the midline CC, and compared their relationships with CC area, as a marker of disease-related atrophy, and with global cognitive data. Radial diffusivity exhibited the strongest correlation to brain atrophy, whereas global cognition was better predicted by mean diffusivity measures. We found that high diffusivity integrals were systematically better predictors of both atrophy and global cognition than mean ROI values.

                  2010.     Location of Affected Pathways in MCI and AD Through FA Comparison

Darryl H. Hwang1, Witaya Sungkarat1, Manbir Singh1

1University of Southern California, Los Angeles, California , USA

Study was conducted to detect common regions in the brain where FA was reduced both in MCI and AD when compared to normals, but reduced more in AD than MCI. Pathways in a normalized space were generated from these regions by sorting normalized DTI tractography. Resulting pathways are consistent with the biology of Alzheimer Disease.

                  2011.     Characteristic Patterns of White Matter Disintegration in Frontotemporal Dementia and Alzheimer’s
                                 Disease by DTI

Yu Zhang1, 2, Norbert Schuff1, 2, An-Tao Du1, Howard J. Rosen2, Joel H. Kramer2, Maria Luisa Gorno-Tempini2, Bruce L. Miller2, Michael W. Weiner1, 2

1Center for Imaging of Neurodegenerative Diseases, VA Medical Center, San Francisco, California , USA; 2University of California, San Francisco, California , USA

Alzheimer’s disease (AD) and frontotemporal dementia (FTD) are two common dementias but difficult to be differentiated. In this study, diffusion tensor imaging (DTI) was used with tractography-based analysis and global analysis in 13 AD patients, 12 FTD, and 13 control (CN) subjects. DTI analyses showed that FTD had significant lower fractional anisotropy (FA) than CN predominantly in the anterior (frontal) and temporal brain; AD had significant lower (FA) than CN predominantly in the posterior (parietal) and temporal brain. These distinct FA patterns of FTD and AD may aid the differential diagnosis between the two types of dementias.

                  2012.     Decreased Olfactory Tract Fiber Integrity in Mild Cognitive Impairment as Revealed by Diffusion
                                 Tensor Imaging

Donna J. Cross1, Yoshimi Anzai1, Jeffery Stevenson1, Kenneth R. Maravilla1, Elaine R. Peskind, Satoshi Minoshima1

1University of Washington, Seattle, Washington, USA


                  2013.     Decrease of Glutathione Levels in a Transgenic Mouse Model of Alzheimer’s Disease Expressing Both
                                β-Amyloid and Tau Pathology

Wen-Tung Wang1, Sang-Pil Lee1, Mary L. Michaelis2, In-Young Choi1

1University of Kansas Medical Center, Kansas City, Kansas, USA; 2University of Kansas, Lawrence, Kansas, USA

The levels of neurochemicals can be altered through various pathological mechanisms, thus providing insights into the disease progression. Neurochemical profiles were acquired from the hippocampus of triple-transgenic mice with mutations in APP, PS1, and tau using ultra-short echo time 1H MRS at 9.4 T. Our preliminary study showed significant decreases of glutathione, a critical antioxidant, in the 19 months old transgenic mouse brain in vivo, indicating increased oxidative stress in AD.

                  2014.     Regional Myo-Inositol Concentration in Mild Cognitive Impairment and Alzheimer Disease Using 1H
                                Magnetic Resonance Spectroscopic Imaging

Malgorzata Siger1, 2, Norbert Schuff1, Xiaoping Zhu1, Michael Weiner1

1Veterans Administration Medical Center, San Francisco, California , USA; 2Medical University of Lodz, Lodz, Poland

In this study, we used spectroscopic imaging (MRSI)  to determine whether both MCI and AD show systematic regional patterns of metabolite abnormalities in white matter and gray matter. Results of our study suggests vulnerability of white matter in the pathology of AD and MCI as indicated by widespread increased myo-inositol in white matter regions. Furthermore, increased myo-inositol may be an even more robust and sensitive marker for MCI and AD than NAA, which was not significantly reduced in white matter compared to aging

                  2015.     Longitudinal 4T Magnetic Resonance Spectroscopy of the Hippocampus in Alzheimer Disease Patients on

Jacob Penner1, 2, Raul Rupsingh1, 2, Matthew Smith3, Jennie Wells, 23, Michael Borrie, 23, Rob Bartha1, 2

1Robarts Research Institute, London, Canada; 2University of Western Ontario, London, Canada; 3Lawson Health Research Institute, London, Canada

Short echo time LASER localized proton magnetic resonance spectroscopy at 4.0 Tesla was used to quantify the levels of glutamate (Glu), N-acetyl aspartate (NAA), and creatine (Cr) in ten newly diagnosed Alzheimer disease patients at baseline and after 4 months of Galantamine treatment. A significant increase was found in the Glu/NAA ratio (p < 0.05) after 4 months, while there were no significant changes in the ratio of Glu/Cr, the absolute Glu, NAA, or Cr concentrations, or cognitive scores.

                 2016.     1H MR Spectroscopy of the Cingulate Gyrus Reveals Evidence for Unique Neurometabolic Profiles for
                               Amnestic and Non-Amnestic Mild Cognitive Impairment

Andreana P. Haley1, Kathleen L. Fuchs2, Sarah Andrea Dunham3, Carol A. Manning2, Jack Knight-Scott3

1The University of Texas at Austin, Austin, USA; 2University of Virginia, Charlottesville, Virginia , USA; 3Children's Healthcare of Atlanta, Atlanta, Georgia, USA

In this work, we demonstrate that differences in regional metabolic patterns can improve the differentiation between amnestic and non-amnestic mild cognitive impairment. Proton MRS measurements in the anterior and posterior cingulate gyrus provide unique metabolic profiles for both diagnoses indicating these sub-types are also unique neuropathologies.

                  2017.     Magnetic Resonance Imaging and Spectroscopy Measures of Cognitive Decline in Mild Cognitive
                                Impairment and Alzheimer’s Disease Converters

Brenda Lynn Bartnik Olson1, Matthew Wagner1, William Britt1, Wolff Kirsch1, Barbara A. Holshouser1

1Loma Linda University, Loma Linda, California , USA

This study compares global brain, white and gray matter volumes as well as cerebral metabolite levels and ratios in tracking cognitive decline in twenty MCI and 13 cognitively normal control subjects. Structural 3D T1-weighted MRI and single voxel 1H MRS of the posterior cingulated gyrus (PCG) studies were performed over a 2-year period with repeat studies approximately every 12 months and neurocognitive testing every 6 months. Results show that the conversion to AD is associated with an increased rate of GM loss and decreases in NAA and Glx levels, compared to cognitively normal aging adults. Baseline NAA and Glx levels had a higher predictive accuracy than tissue or CSF volume.

                  2018.     Correlation Between Global Severity Scales in Cognitive Impairment (GDS and CDR) and Magnetic
         Resonance H1 Spectroscopy, Perfusion Weighed Imaging and Diffusion Weighted Imaging

Jorge Humberto Davila Acosta1, Nicolas Nicolas Fayed1, Antonio Oliveros Cid1

1Hospital Quiron, Zaragoza, Spain

The clinical evaluation, the diagnosis and the following of patients with AD and MCI is very complex. The use of clinical tools as GDS and CDR help to classify these patients, to compare them and to evaluate the response to the treatment. Some studies have found a good correlation between these clinical scales and the pathologic stages in AD described by Braak. The use of MRS, PWI and DWI in patients with AD and MCI has showed structural and metabolic changes. These changes can help in the clinical evaluation of patients with AD and MCI if a good correlation with the clinical stages is demonstrated.

Text Box:  
                  2019.     Association Between the Apolipoprotein E ε4 Gene Polymorphism and Cerebral Ventricular Dilatation
        Measured from Serial Magnetic Resonance Imaging in Subjects Enrolled in the Alzheimer’s Disease
        Neuroimaging Initiative
 [Not Available]

Sean M. Nestor1, Raul Rupsingh1, Vittorio Accomazzi, Michael J. Borrie2, Matthew Smith3, Jennie Wells2, Jennifer Fogarty2, Robert Bartha1

1Robarts Research Institute, London, Canada; 2University of Western Ontario, London, Canada; 3Lawson Health Research Institute, London, Canada

The current study compares ventricular dilatation between carriers for the apolipoprotien E ε4 allele (ε4+) and subjects with other polymorphisms (ε4-), in subjects with Alzheimer disease(AD) and mild cognitive impairment (MCI), over a short interval. Six-month longitudinal data were selected from the Alzheimer’s Disease Neuroimaging database, which included 502 subjects (elderly controls, MCI, and AD). Baseline and six-month unprocessed 3D T1-weighted MP-RAGE 1.5 Tesla MR images, neurocognitive, and genetic measures were acquired. Ventricular volume was computed using a semi-automated region-growing algorithm (Cedara Software). Ventricular dilatation was significantly greater in the AD ε4+ group compared to AD ε4- subjects (p< 0.05).

Text Box:  
                  2020.     Shifting Regional Atrophy Rates in the Progression from Normal Aging to Alzheimer’s Disease Quantified
        by Fluid Registration

Jasper D. Sluimer1, Wiesje M. van der Flier1, Giorgos B. Karas1, Ronald A. van Schijndel1, Josephine Barnes2, Richard G. Boyes2, Keith S. Cover1, Silvia D. Olabarriaga3, Nick C. Fox2, Philip Scheltens1, Hugo Vrenken1, Frederik Barkhof1

1VU University Medical Center, Amsterdam, Netherlands; 2University College London, London, UK; 3Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands

In 64 patients with Alzheimer’s disease (AD), 44 patients with mild cognitive impairment (MCI) and 34 controls, we determined regional atrophy rates in six different brain regions by applying Fluid nonlinear registration software to 3D coronal MPrage images from two timepoints. In MCI, the temporal lobe shows the greatest atrophy rate. In AD patients, the medial temporal lobe shows an atrophy rate comparable to MCI, while the remaining part of the temporal lobe demonstrates an even higher rate of atrophy. Moreover, atrophy also accelerates in parietal and occipital lobes.

                  2021.     Regional Atrophy Demonstrated in Alzheimer’s Disease and Mild Cognitive Impairment (MCI) Using
                               Minimal Post-Processing Time

David L. Henderson1, John Frederic Schenck1, Natalie A. Staples1, Earl A. Zimmerman2

1General Electric Global Research, Niskayuna, USA; 2Albany Medical College, Albany, USA

Quantitative T2-mapping holds great promise for increasing the utility of MRI in the management of neurodegenerative diseases (NDDs), such as Alzheimer's disease, which affect millions of patients. Although many studies have the potential of quantitative brain imaging, they usually require prohibitive levels of time-consuming postprocessing analysis to provide useful results. We show examples of semi-automated image analysis capable of quantifying regional brain atrophy in various NDDs that may greatly reduce this bottleneck and promote the widespread use of MRI in these conditions.

                  2022.     Sodium MRI Enhancement of the Medial Temporal Lobe in Mild Alzheimer’s Disease

Eric Albert Mellon1, David T. Pilkinton1, Reddy Shashank Beesam1, Christopher M. Clark1, Elias R. Melhem1, Walter R. Witschey1, Arijitt Borthakur1, Ravinder Reddy1

1University of Pennsylvania, Philadelphia, Pennsylvania, USA

There is substantial interest in quantitative techniques for the study of Alzheimer’s Disease (AD) to track the progression of disease for both prognosis and to monitor new therapies for AD. Towards this, presented is a study of changes in the medial temporal lobes by sodium MRI within the brains of patients with AD versus non-demented elderly controls on a clinical 3T scanner. An optimized Gradient Recalled Echo readout shows a statistically significant 12% enhancement between 4 mild AD patients and 5 age-matched control subjects. Work is already underway to elucidate the mechanisms and specificity of this enhancement.

                  2023.     T2 Relaxometry and Volumetry of Postmortem Human Hippocampi

Robert John Dawe1, David A. Bennett2, Julie A. Schneider2, Sunil Vasireddi1, Konstantinos Arfanakis1

1Illinois Institute of Technology, Chicago, Illinois, USA; 2Rush University Medical Center, Chicago, Illinois, USA

One advantage of postmortem MRI over in vivo imaging is that the in vitro tissue can be held nearly motionless indefinitely, making it possible to perform very high resolution imaging. This opportunity is exploited in the current study. Thirty-eight cadaveric human brains were scanned, and the T2 values and volumes of the hippocampi were correlated with the subjects' MMSE scores and which hemisphere was imaged (right or left). It was found that in postmortem brain specimens, low MMSE scores are associated with lower hippocampal T2 values.

                  2024.     Correlation of Increased R2 with B0 and Cognitive Status

Sarah Pachtman1, Himachandra Chebrolu1, Charles Dennis Smith1, Peter Andrew Hardy1

1University of Kentucky, Lexington, USA

                  2025.     Quantitative Comparison of Cerebral Blood Volume Between Patients with Alzheimer's Disease and
                                 Elderly Controls

Jinsoo Uh1, Kelly Lewis-Amezcua1, Kristin Martin-Cook1, Myron Weiner1, Ramon Diaz-Arrastia1, Hanzhang Lu1

1University of Texas Southwestern Medical Center, Dallas, USA

Recent study suggests that Alzheimer’s Disease (AD) is featured by vascular factors, which may be useful for better understanding and early marker of AD. Utilizing a novel MR technique, Vascular-Space-Occupancy (VASO)-MRI, we quantitatively assessed Cerebral Blood Volume (CBV) of the entire brain on mild AD patients compared with age-matched controls. In particular, we identified brain regions that show significant differences between the two groups using ROI and voxel-by-voxel analyses based on elastic co-registration. Our study revealed that mild AD patients manifest significant reduction of CBV by 10-20% particularly at limbic system and basal ganglia regions.

                  2026.     Detaild FMRI Investigation of Multiple Cognitive Domains in Patients with Amnesic MCI

delia Lenzi1, 2, Laura Serra3, patrizia Pantano1, eraldu Paulesu, franco Giubilei1, roberta Perri3, gian luigi Lenzi1, carlo Caltagirone3, emiliano Macaluso3, marco Bozzali3

1Universita"La Sapienza", Rome, Italy; 2Fondazione Santa Lucia, IRCCS , Rome, Italy; 3Fondazione Santa Lucia, IRCCS, Rome, Italy

Amnesic Mild Cognitive Impairment (a-MCI) is considered as a frequent prodromal state of Alzheimer’s disease. Aim of this study was to investigate, using fMRI, the patterns of activation in patients with a-MCI when performing multiple tasks that selectively engage specific cognitive domains. 15 patients with MCI and 10 sex- and age-matched group of healthy controls were studied  during tasks assessing  memory functions, spatial attention, and empathic ability. During all tasks there was a significantly increased activation in the same network observed in  healthy controls. This might reflect an initial compensation that explains the maintenance of performance in patients with MCI.

                  2027.     Direct Visualization of Senile Plaques Using Clinical Field-Strength MRI and a Cholesterol-Fed Rabbit
                                Model of Alzheimer’s Disease

John A. Ronald1, 2, Yuanxin Chen1, Lisa M. Bernas1, 2, Robert A. Hegele1, 2, Kem A. Rogers2, Brian K. Rutt1, 2

1Robarts Research Institute, London, Canada; 2University of Western Ontario, London, Canada

We demonstrate a novel model of Alzheimer’s disease by feeding rabbits a low-level cholesterol diet for extended periods of time.  These animals develop extracellular beta-amyloid rich plaques similar to compact plaques found in humans, and these plaques also reliably accumulate iron.  High-resolution MRI of excised brains revealed signal voids throughout the brain parenchyma that directly correlated to iron-laden plaques in matched tissue sections.  Minimal voids were seen in control brains.  This is both the first successful attempt at direct imaging of plaques formed in a large animal model and first successful clinical field-strength imaging of plaques in any model. 

                  2028.     Improved Magnetic Resonance Microimaging of Individual Amyloid Plaques in Alzheimer's Transgenic

Ryan Chamberlain1, Denise Reyes2, Geoffry L. Curran2, Thomas M. Wengenack2, Joseph F. Poduslo2, Michael Garwood1, Clifford R. Jack2

1University of Minnesota, Minneapolis, Minnesota, USA; 2Mayo Clinic College of Medicine, Rochester, Minnesota, USA

One of the principal pathologies of Alzheimer’s disease is amyloid plaques, the reduction of which has been identified as a major therapeutic objective.  Plaques appear hypointense relative to background tissue on both T2- and T2*-weighted images.  The major limitations of existing approaches are long scan time and low CNR.  This investigation analyzes the ability to increase the CNR over a previously verified spin echo sequence by summing multiple spin echoes and using multiple spin echo susceptibility weighted imaging.

                  2029.     Comparison of Amyloid Plaque Characteristics in Transgenic Mouse Models of AD Using MR Microscopy

Palamadai Nilakantan Venkatasubramanian1, 2, Gheorghe Iordanescu1, Alice M. Wyrwicz1

1ENH Research Institute, Evanston, Illinois, USA; 2Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA

Amyloid plaques in two APP transgenic mouse lines were imaged directly without the use of external contrast agent.  Plaque characteristics such as size, number and regional distribution were different between the two transgenic lines.

                  2030.     Iron is a Prerequisite for Direct Visualization of Alzheimer’s Plaques in Animal Models

Yuanxin Chen1, John A. Ronald1, 2, Lisa M. Bernas1, 2, Robert A. Hegele1, 2, Kem A. Rogers2, Brian K. Rutt1, 2

1Robarts Research Institute, London, Canada; 2University of Western Ontario, London, Canada

Our lab has shown that direct visualization of Alzheimer’s disease (AD) plaques in a cholesterol-fed rabbit model of AD is possible using clinical-field strength ex vivo MRI.  These rabbits formed plaques with dramatic iron accumulation. Here, we performed MRI in an additional two AD models including rabbits fed a high-cholesterol diet for a short time and an AD transgenic mouse. We demonstrate that amyloid plaques formed in these models without iron deposits were not detectable on MR imaging. This suggests that the ability to detect AD plaques in animal models is due to their clear association with excess iron.

                  2031.     Overexpression of SOD-2 Rescues Reduced Cerebral Blood Flow in the Tg2576 (APP) Mouse Model
                               of Alzheimer’s Disease

Samir Kamalesh Amin1, Cynthia Massaad1, Lingyun Hu1, Eric Klann2, Robia G. Pautler1

1Baylor College of Medicine, Houston, Texas, USA; 2New York University, New York City, New York, USA

A-beta peptide accumulation is pivotal in Alzheimer’s disease (AD) pathogenesis. Few studies have addressed A β involvement in oxidative impairment of cerebrovascular regulation in AD. We studied this aspect of A β pathogenesis using transgenic mice with Flow-sensitive Alternating Inversion-Recovery EPI arterial spin labeling. We wanted to determine if overexpression of the reactive oxygen species scavenger SOD-2 in APP mice leads to reversal of cerebral blood flow attenuation. We found that oxidative damage on cerebrovasculature occurs early in the pathogenesis and can be “rescued” with SOD-2 overexpression. Our present findings support the idea that ROS formation precedes plaques in the AD pathogenesis.

                  2032.     Cerebrovascular Alterations in APP23 Transgenic Mice Modelling Alzheimer’s Disease Studied
                                Non-Invasively by MRI

Nicolau Beckmann1, Stefan Zurbruegg1, Catherine Cannet1, Christelle Gérard1, Dorothee Abramowski1, Karl-Heinz Wiederhold1, Matthias Staufenbiel1

1Novartis Institutes for BioMedical Research, Basel, Switzerland

MRI was used to detect in APP23 mice the effects of cerebral amyloid angiopathy. Endorem® was administered i.v. 24h before imaging. Foci of signal attenuations became apparent in the brain cortex as well as in thalamic regions of 16-month-old APP23 mice. An age-dependent increase in the number of foci displaying attenuated signal was observed in older animals. With a few exceptions, these foci were absent in age-matched, wildtype littermate controls. Histology revealed that, at sites of signal loss detected by MRI, iron was localized in or around damaged vessels, entrapped in microglia/macrophages.

                  2033.     Geriatric Rhesus Monkeys Have in Vivo Proton MRS Signatures of Human Alzheimer's Disease

Rose-Ann Blenman1, Marie Holahan1, Denise Welsh1, Jacquelynn Cook1, Richard Hargreaves1, Donald Williams1

1Merck & Co. Inc., West Point, Pennsylvania, USA

Proton MRS biomarkers were assessed in young adult and geriatric Rhesus monkeys.  Since geriatric Rhesus monkeys (≥ 24 years) have been characterized as models of neurodegenerative disease, our hypothesis was that geriatrics would have altered biochemical profiles suggesting neuronal degeneration and glial activation.  MRS in the posterior cingulate of geriatric Rhesus showed that NAA/tCr decreased by ≈15%, mI/tCr increased by ≈30%, and tCho/tCr decreased by ≈20% as compared to the young adult monkeys (≤15 years).  Results also showed that NAA/tCr, mI/tCr and tCho/tCr are highly correlated with age and that tCho/tCr is correlated with NAA/tCr and NAA/mI.

                  2034.     Interhemispheric Visual Integration in Alzheimer's Disease: Decrease of FMRI BOLD Response in
                                 VP/V4 Areas

Laurent Uldry1, Isabelle Bourquin1, Andrea Brioschi1, Joseph Ghika1, Philippe Maeder1, Reto Meuli1, Eleonora Fornari1

1Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland

During an fMRI study, we compared 15 newly diagnosed Alzheimer (AD) patients with 15 age-matched subjects and investigated higher-order visual areas to detect AD-related malfunction before the appearance of clinical signs. Our paradigm addresses visual interhemispheric integration functions, with stimuli obeying (IG) or not (OG) the Gestalt principle. We found that the interhemispheric integration process (IG vs. OG contrast) induced BOLD increase within VP/V4 areas. AD patients showed the same activation pattern as control subjects, but characterized by a reduction of intensity and extent, possibly due to an already decreased myelination of cortico-cortical connections involved in spatial integration.

                  2035.     Cerebral Blood Flow Measurement in Alzheimer Disease and Mild Cognitive Impairment Using
                                 QUASAR and 3T MRI

Takashi Yoshiura1, Tomoyuki Noguchi1, Akio Hiwatashi1, Osamu Togao1, Koji Yamashita1, Eiki Nagao1, Hidetaka Arimura1, Tomoyuki Okuaki2, Ivan Zimine2, Marc van Cauteren2, Hiroshi Honda1

1Kyushu University, Fukuoka, Japan; 2Philips Medical Systems, Japan, Tokyo, Japan

Nine patients with MCI, seven patients with AD and seven normal subjects were studied using a quantitative ASL pulse sequence (QUASAR) and 3T MRI. Absolute CBFs were measured in whole gray matter region, bilateral thalami and bilateral inferior parietal (IP) cortices. Relative CBF values of bilateral IP cortices normalized by whole gray matter CBF and by thalamic CBF were also obtained. Both absolute and relative CBFs in the right IP cortex were significantly decreased in AD group. Moreover, relative CBF in right IP normalized by whole gray matter CBF was significantly decreased in MCI group in comparison with normal group.


Developmental Brain Disorders

Hall D                                   Thursday 13:30-15:30                                                                                                                                           

                  2068.     Altered Diffusion Tensor MRI Indices of Frontal Cortical and Basal Ganglia in Children with Tourette
                                 Syndrome Assessed by Voxel-Based Analysis Study

Malek Makki1, Michael Behen1, Elizabeth Primeau1, Benjamin Wilson1, Arpi Bhatt1, Harry Chugani1

1Wayne State University, Detroit, Michigan, USA

The neurobiological abnormalities underlying Tourette syndrome (TS) remain unknown despite various biochemical, neuroimaging, neurophysiological, and genetic studies that suggest a role of the basal ganglia and related thalamic and cortical regions. MRI studies of TS have reported volume reductions in the basal ganglia, frontal cortex, hippocampal gyrus, and white matter. We investigated interhemispheric brain asymmetry in children with TS using voxel-based analysis of diffusion tensor indices. Results show abnormal white matter integrity in regions comprising the fronto-striato-thalamic circuit in children with TS as compared to age-matched healthy controls, extending previous work that has shown this circuit as involved in TS.

                  2069.     Abnormal White Matter Integrity of Striato-Thalamic Structures in Children with Tourette Syndrome

Malek Makki1, 2, Mike Behen1, Arpi Bhatt1, Harry Chugani1

1Wayne State University, Detroit, USA

Despite a plethora of evidence suggesting that the fronto-striato-thalamic (FST) circuitry is abnormal in patients with Tourette Syndrome (TS), the structural integrity of white matter pathways has not yet been directly investigated. We used DT-MRI to test the hypothesis that TS may be associated with specific white matter abnormalities in the lentiform nuclei, thalamus, and caudate nucleus, and that individuals with TS will show decreased FA and increased ADC in fibers of FST as compared to healthy controls. We also examined whether abnormalities on DTI are associated with tic severity and obsessive-compulsive disorder and attention deficit hyperactivity disorder comorbidity.

                  2070.     Application of Probabilistic Fiber Tracking for the Quantitative Assessment of the Connectivity Pattern
                                Between Basal Ganglia and Frontal Cortex in Children with Tourette Syndrome

Otto Muzik1, Malek Makki2, Darshan Pai2, Anita Dias3, Jing Hua2, Harry Chugani1

1Wayne State University, Detroit, Michigan, USA; 2Wayne State University, USA; 3CHM PET Center, Detroit, Michigan, USA

This paper describes a method for the quantitative assessment of fiber tract connectivity strength based on Bayesian probabilistic tractography. For each fiber path a normalized probability value is calculated which characterizes the probability of connection between two predefined cortical areas. We applied this method to DTI data derived from children with Tourette Syndrome (TS) and pediatric controls to evaluate the connectivity strength between subcortical and cortical regions. Our findings indicates an abnormal connectivity pattern between the head of caudate and frontal lobe regions in children with TS as compared to control children.

                  2071.     Transverse Relaxation Rime Abnormalities of the Basal Ganglia in Tourette Syndrome

Yann Gagnon1, Tim Devito1, Janet Hendry1, N Gelman1, N Rajakumar2, P Williamson2, R Nicolson2, Dick Drost1

1University of Western Ontario, Lawson Health Research Institute, London, Canada; 2University of Western Ontario, London, Canada

The transverse relaxation time (T2) is a quantitative parameter of magnetic resonance imaging which is indicative of the molecular environment in brain tissue.  In this study, T2 times of lobar white matter were evaluated in a group of patients with autism.  Images obtained at 3 Tesla using the GESFIDE technique were spatially normalized for statistical analysis.  Patients in this study had an increase in left-sided white matter T2 as well as an increase in frontal and parietal white matter T2.

                  2072.     Possible Sources of Functional Connectivity and Under-Connectivity in Adolescents with Autism
                                 Spectrum Disorders

Tyler Bridgeland Jones1, Lauren Kenworthy, 12, Laura K. Case1, Shawn C. Milleville1, Peter Anthony Bandettini1, Alex Martin1, Rasmus Matthias Birn1

1National Institutes of Health, Bethesda, Maryland, USA; 2Childrens National Medical Center, Washington, District Of Columbia, USA

Adolescents with autism spectrum disorders (ASD) show decreased functional connectivity relative to typically developing individuals, supporting a model of underconnectivity in autism.  Employing an overt fluency task to probe language and executive deficits typical of ASD, we aim to determine what factors contribute to the decreased correlations of spatially remote BOLD fMRI time series observed in ASD.  By sequentially regressing out various factors, including differential task activation, trial-to-trial task response variability, and certain scanner artifacts, we conclude that the disruption in functional connectivity in ASD is at least partially due to differences in task-unrelated, or “spontaneous,” neuronal fluctuations.

                  2073.     A Study of Underconnectivity in Autism Using DTI: W-Matrix Tractography

Jee Eun Lee1, David Hsu1, Andrew L. Alexander1, Mariana Lazar2, Erin D. Bigler3, Janet E. Lainhart3

1University of Wisconsin, Madison, Wisconsin, USA; 2New York University School of Medicine, New York, New York, USA; 3University of Utah, Salt Lake City, Utah, USA

A novel probabilistic method for diffusion tensor tractography (W-matrix tractography) was developed to study underconnectivity in autistic children. This algorithm incorporates measures of intravoxel and intervoxel structure and allows simultaneous multi-directional branching of white matter tracts. In preliminary testing comparing 43 autistic subjects with 34 matched controls, we find a strong tendency to segregate the autistic from the control populations, particularly in the younger subjects. With further tuning, W-matrix tractography may be useful in the early diagnosis of autism.

                  2074.     White Matter Abnormalities in Youth with High Functioning Autism or Asperger Syndrome Using DTI
                                Tractography and Voxelwise Analyses
[Not Available]

Manzar Ashtari1, Joel Bregman2, Shana Nichols2, Carolyn McIlree3, Linda Spritzer2, Andrew Adesman4, Melissa Narain5, Babak Ardekani6

1Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; 2Fay J. Lindner Autism Center, Bethpage, New York, USA; 3University of Vermont, Burlington, USA; 4Schneider Children's Hospital, New Hyde Park, New York, USA; 5North Shore LIJ Health System, Glen Oaks, New York, USA; 6Nathan Kline Institute of Psychiatry, Orangeburg, New York, USA

We have applied diffusion tensor imaging to a whole-brain voxelwise analysis and tractography in a group of high-functioning youth with Autism Spectrum Disorder (ASD) and demographically matched controls.  Results from tractography and voxelwise analysis showed increased FA in the posterior portion of the cingulate bundle (limbic system).  Increased FA positively correlated with the social-emotional reciprocity and autistic mannerism of the ASD patients. Our data suggest that alterations in the limbic system secondary to suboptimal connectivity may lead to core impairments of social interaction and behavior associated with the autism phenotype.

                  2075.     XXY (Klinefelter Syndrom): A FMRI Study of Prepubertal Boys

Song Lai1, Fumiko Hoeft2, Jianrong Shi1, John Lackey1, Udomchai Techavipoo1, Adam Flanders1, David Roeltgen1, Allan L. Reiss2, Judith Ross1

1Thomas Jefferson University, Philadelphia, Pennsylvania, USA; 2Stanford University, Stanford, California , USA

A fMRI study was conducted to investigate the functional brain differences between prepubertal boys with KS (8-12 years) and age-matched control boys, and to examine function associated with androgen replacement in KS, so as to improve our understanding of cognitive deficits associated with KS and androgen deficiency. Relative to the age-matched control group, boys with KS showed aberrant activation patterns in a regional specific manner, depending on the cognitive operation (language and motor functions). Aberrant activation patterns showed ‘normalization (i.e., increase in activation)’ with androgen treatment.

                  2076.     MRI of Prepubertal Boys with Klinefelter Syndrom: A Voxel-Based Morphometric Study  

Song Lai1, John Lackey1, Jianrong Shi1, Udomchai Techavipoo1, David Roeltgen1, Adam Flanders1, Fumiko Hoeft2, Allan L. Reiss2, Judith Ross1

1Thomas Jefferson University, Philadelphia, Pennsylvania, USA; 2Stanford University, Stanford, California , USA

A voxel-based morphometry study was conducted to investigate the structural brain differences between prepubertal boys with KS (8-12 years) and age-matched control boys in order to obtain insight of the underlying neuroanatomy of the KS cognitive phenotype. Boys with KS were found to have smaller brain volumes in regions related to cognitive functions of interest, including the left insula, ventrolateral prefrontal and temporal lobes, [language function], the bilateral anterior limb of the internal capsule (ALIC), globus pallidus, pre and post-central gyri and corpus callosum [for bimanual motor function], and the dorsolateral prefrontal and parietal lobes [working memory function.

                  2077.     Deformation Based Morphometry of Brain Structure in Children with Difficulties in Mathematics

Zhaoying Han1, 2, Lynn Fuchs1, Nikki Davis1, Christopher J. Cannistraci2, Adam W. Anderson2, John C. Gore2, Benoit M. Dawant1

1Vanderbilt University, Nashville, Tennessee, USA; 2Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA

Anatomical differences between normal children (NC) and children with math difficulties (MD) are investigated with deformation based morphometry in a population comprised of 20 pairs of age and gender matched NC and MD children. High resolution MR images have been acquired and one population average has been computed using a non-rigid registration technique that produces dense deformation fields. Statistically significant differences in the deformation fields between the two populations were found in several areas that have been previously reported in functional studies as related to computation. These findings may explain the differences that have been observed in functional studies.

                  2078.     Networks Utilized for Receptive Speech in Children with Right and Left Unilateral Sensorineural Hearing Loss

Vincent Jerome Schmithorst1, Scott Kerry Holland1

1Children's Hospital Medical Center, Cincinnati, Ohio, USA

Children with severe-to-profound unilateral sensorineural hearing loss (USNHL) show deficits in higher-order auditory processing tasks.  We investigate the task of receptive speech using functional MRI (fMRI) in children with right and left USNHL.  The paradigm consisted of a “modified token” task.  Subjects viewed an arrow moving to point to two shapes shown on a video screen.  Subjects would respond if the speaker correctly described the motion of the arrow.  Using group Independent Component Analysis (ICA), activation was shown in auditory processing and higher-order integrative regions.  Results also indicate the preferential formation of auditory processing pathways ipsilateral to the hearing ear.

                  2079.     Differences in White Matter Microstructure Between Children with Right and Left Unilateral Sensorineural
                                Hearing Loss

Vincent Jerome Schmithorst1, Scott Kerry Holland1

1Children's Hospital Medical Center, Cincinnati, Ohio, USA

Children with right unilateral sensorineural hearing loss (USNHL) show greater deficits in academic performance as compared to children with left USNHL.  We investigate possible differences in white matter microstructure using diffusion tensor MRI (DTI).  Children with right USNHL displayed greater fractional anisotropy (FA) in the genu and splenium of the corpus callosum, in frontal regions bilaterally, and in the left occipital lobe.  Children with left USNHL displayed greater FA in temporo-parietal white matter in the left hemisphere.  Results indicate preferential formation of inter-hemispheric pathways in children with right USNHL, and intra-hemispheric pathways in the left hemisphere in children with USNHL.

                  2080.     Networks Used for Interpretation of Speech-In-Noise in Children with Unilateral Sensorineural Hearing Loss

Vincent Jerome Schmithorst1, Scott Kerry Holland1

1Children's Hospital Medical Center, Cincinnati, Ohio, USA

We used functional MRI (fMRI) in conjunction with an audiological test performed in-scanner to investigate the source of auditory processing deficits in children with unilateral sensorineural hearing loss (USNHL).  The task involves interpretation of speech-in-noise at varying levels of SNR.  Using group Independent Component Analysis, networks were found related to task difficulty.  Two attentionally-related components were found with activation in the frontal lobes.  Two auditory-related components were also found, with activation in Wernicke’s area and its RH homolog, and activation in the left IFG (BA 45/47).  Differences were also found between children with left and right USNHL.

                  2081.     MRSI Detects Abnormalities in Normal-Appearing Frontal Lobe of Sturge-Weber Syndrome Patients

Zhifeng Kou1, Meng Li1, Quan Jiang, Navid Seraji, Yang Xuan1, E Mark Haacke1, Harry T. Chugani, Csaba Juhasz, Jiani Hu1

1Wayne State University School of Medicine, Detroit, Michigan, USA

This study was to determine whether MRSI can improve detection of frontal lobe involvement in children with SWS. Among 16 children (age: 0.9 -10.4 years) with unilateral SWS, 8 children presented normal-appearing frontal lobes on conventional MRI, but 7 of them showed abnormal NAA and/or choline content in the frontal lobe of the affected hemisphere. Lower frontal lobe gray matter NAA was associated with earlier onset of seizures (r = 0.76; p = 0.04) and was an excellent predictor of motor function (r=-0.89, p<0.001). MRSI is more sensitive than conventional structural MRI for detection of frontal lobe involvement in SWS.


Animal Models: Demyelination & Regeneration in Brain & Spine

Hall D                                   Thursday 13:30-15:30                                                                                                                                           

                  2105.     q-Space MRI and DTI of Excised Myelin Deficient Rat Brains

Amnon Bar-Shir1, Ian D. Duncan2, Yoram Cohen1

1Tel-Aviv University, Tel-Aviv, Israel; 2University of Wisconsin, Madison, USA

High b-value q-space diffusion MRI was reported to be sensitive to myelination disorders. In the present study we used high b-value q-space diffusion MRI and conventional DTI to describe, for the first time,  the diffusion characteristics of myelin-deficient (md) rat brains and their age-matched controls. This study clearly demonstrates that myelin affects, significantly, all three diffusion indices obtained from q-space DWI (i.e. displacement probability and kurtosis). This study also shows that FA, extracted from conventional DTI, blurs the differences between the two groups.

                  2106.     Evaluation of Demyelination and Remyelination in Mouse Spinal Cord Using Multiexponential T2 and
                                Magnetization Transfer Ratio

Cheryl R. McCreary1, 2, Thorarin A. Bjarnason2, Viktor Skihar1, 2, J Ross Mitchell1, 2, V Wee Yong1, 2, Jeff F. Dunn1, 2

1Unversity of Calgary, Calgary, Canada; 2University of Calgary, Calgary, Canada

Identification of remyelination is important in the evaluation of potential treatments of demyelinating diseases like multiple sclerosis. Areas of demyelination with spontaneous remyelination have been observed in mice after a local injection of lysolecithin. The aim of this study was to determine if multi-exponential T2 analysis and magnetization transfer imaging, both indicative of myelin content, could detect changes in myelination, particularly remyelination, of the cervical spinal cord in mice treated with lysolecithin.  We found that the short and intermediate T2 components showed significant changes over time and had began to return to control levels, while the MTR remained lower over the time course studied.

                  2107.     Significant Brain Atrophy Precedes the Onset of Disability in a Murine Model of Multiple Sclerosis

Istvan Pirko1, Yi Chen1, Jeremiah McDole1, Scott Dunn2, Diana Lindquist2, Aaron J. Johnson1

1University of Cincinnati, Cincinnati, Ohio, USA; 2Cincinnati Childrens Hospital Medical Center, Cincinnati, Ohio, USA

Brain atrophy is widely recognized in MS, but its pathomechanism remains unclear. Extensive central atrophy has not been reported in MS models. We demonstrate significant brain atrophy in TMEV infected SJL mice, an accepted MS model. Brain parenchymal fraction and ventricular volume analysis showed significant atrophy as early as 3 months, whereas motor deficits became significant at 4 months after induction. Atrophy progressed until 6 months, motor disability until 9 months after induction. NAA decrease accompanied the progressive atrophy. This model will enable us to investigate the pathomechanism of brain atrophy, and may lead to novel therapies addressing MS-related neurodegeneration.

                  2108.     Mouse Brain Diffusion Tensor Magnetic Resonance Imaging (DT-MRI):Assessment of Demyelination
                                 and Recovery

Laura Adela Harsan1, Dominik Paul1, Dominik von Elverfeldt1, Jerome Steibel2, Jürgen Hennig1, Said M. Ghandour2

1University Hospital Freiburg, Freiburg, Germany; 2Université Louis Pasteur, Strasbourg, France

In vivo DT-MRI was used to quantify the demyelination extent and the effects of a novel thyroid hormone (T3) based therapy, applied to induce recovery in the chronic demyelinated mouse brains. Long-term cuprizone treatment in mice resulted in severe and irreversible brain demyelination. The pathology caused changes of DT-MRI derived parameter values, including loss of anisotropy and increase of radial water diffusion values, D(radial). T3 hormone injections restored progressively a normal level of myelin. The microstructural reorganization of the white matter fiber tracts during the remyelination involved gradual recovery of the white matter anisotropy and restoration of normal D(radial) values.

                  2109.     Radial Diffusivity Reveals a Role of Fibroblast Growth Factor 2: Inhibition of Remyelination After
                                Chronic Demyelination

Mingqiang Xie1, Regina C. Armstrong2, Sheng-Kwei Song3

1Washington University in St. Louis, St. Louis, Missouri, USA; 2Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA; 3Washington University, St. Louis, Missouri, USA

SynopsisMultiple sclerosis (MS) is an inflammatorily repeated or chronic demyelinating disease.  Although populations of oligodendrocyte progenitors (OP) persist in the chronically demyelinating lesions, they typically fail to differentiate into myelinating oligodendrocytes.  Previous study showed that absence of fibroblast growth factor 2 (FGF2) promotes OP differentiation into remyelinating oligodendrocytes and enhances remyelination.  In this study, to monitor the spatial and temporal progression of spontaneous remyelination non-invasively, in vivo DTI biomarker of myelination, radial diffusivity was measured longitudinally in cuprizone treated live FGF2 -/- mice throughout the course of recovery period.  The result showed that radial diffusivity in FGF2 -/- mice increased significantly following 12 weeks of cuprizone ingestion and returned to the control level at the end of the 12-week recovery period.  Therefore, DTI detection was a sensitive measure for in vivo detection of the improved repair of chronic demyelination.

                  2110.     Dynamics of USPIO Contrast in the Central Nervous System Unraveled in an Animal Model of Multiple

Raoul Oude Engberink1, Elga de Vries2, Annette van der Toorn1, Susanne van der Pol2, Christien Dijkstra2, Erwin Blezer1

1University Medical Center Utrecht, Utrecht, Netherlands; 2VU Medical Center Amsterdam, Amsterdam, Netherlands

We studied the fate of USPIO longitudinally in a rat model of multiple sclerosis. Repetitive MRI was performed within a 6h period following a single intravenous USPIO injection both at onset as peak of the disease. Contrast effects in the brain are detected in 1h after injection and histological validation at 6h shows extra-cellular USPIO in the brain parenchyma. Signal changes in the brain are no longer detected 72h after injection and imaging of the cervical lymph nodes reveals USPIO accumulation over time. This study identifies USPIO as a marker for BBB damage in an early time frame.

                  2111.     Evaluating Wallerian Degeneration in Visual Pathway of EAE Mice

Shu-Wei Sun1, Hsiao-Fang Liang1, Anne H. Cross1, Sheng-Kwei Song1

1Washington University School of Medicine, St Louis, Missouri, USA

In this study, the feasibility of using axial and radial diffusivities in characterizing the primary and secondary axonal damage of EAE mice was evaluated. The decreased axial followed by increased radial in optic tract (OT) suggested that OT was likely damaged by the Wallerian degeneration.  Since Wallerian degeneration can be delayed in Wlds mice, the delayed damage of OT in Wlds EAE, i.e., one month later than the damage to optic nerve (ON), supported that OT damage is a secondary degeneration originating from the initial ON damage.

                  2112.     Axial Diffusivity in Optic Nerve Correlates Retinal Ganglia Cell Loss in EAE Mice

Shu-Wei Sun1, Hsiao-Fang Liang1, Anne H. Cross1, Sheng-Kwei Song1

1Washington University School of Medicine, St Louis, Missouri, USA

Axonal and neuronal loss is the primary cause of the permanent disabilities in patients with MS.  However, the relation between axonal and neuronal damage is still not clearly. Derived from DTI, axial and radial diffusivities have been used to detect axonal and myelin in optic nerve from EAE mice, an animal model for human MS.  In this study, significant correlations between retinal ganglion cells (RGC, the cell body of optic nerve axons) loss and DTI abnormalities to optic nerve were demonstrated.  This study suggested a causal relationship between the observed axonal and neuronal injuries in EAE mice.

                  2113.     Focal Lesions Do Not Cause Neurological Impairment in EAE: Correlating Histology with in Vivo DTI

Matthew D. Budde1, Sheng-Kwei Song1

1Washington University, Saint Louis, Missouri, USA

A decrease in axial diffusivity correlates with both axonal damage and hindlimb motor function in the spinal cord white matter of mice with experimental autoimmune encephalomyelitis (EAE), a model of Multiple Sclerosis.  However, mice with EAE have varying degrees of long-term impairment as well as heterogeneous distributions of lesions.  In the current study, both DTI parameter maps and histological sections stained for axonal damage were registered to a common space to address the relationship between localized axonal damage and neurological impairment in EAE.  Both modalities demonstrate axonal damage is present throughout the white matter, not solely within lesions.

                  2114.     High Resolution 1H NMR Spectroscopic Based Metabolomic Urine Analysis of EAE, an Experimental Murine
                            Model of Multiple Sclerosis

Harold G. Parkes1, Sarah Romero Shorter2, Po-Wah So3, David Baker4, Gavin Giovannoni4, Gareth Pryce4, Klaus Schmierer1

1University College London, London, UK; 2Birkbeck College, London, UK; 3Hammersmith Hospital, Imperial College London, London, UK; 4Queen Mary University of London, London, UK

EAE is an experimentally induced autoimmune disease in mice, exhibiting a similar disease progression as multiple sclerosis (MS) pathology in man including different pathology categorised as acute, chronic, remitting and relapse.  1H NMR spectroscopic analysis of urine showed significantly decreased excretion of certain metabolites, and specific to each pathology type.  Thus, urine biomarkers may be generated by 1H spectroscopy to aid diagnosis and monitoring as well as pathological classification of clinical MS.

                  2115.     Systemic Reactivation of a Focal MOG-EAE Lesion in Rat Brain Revealed by MRI and

sebastien Serres1, Yanyan Jiang1, Damian Tyler1, Daniel Anthony1, Nicola Sibson1

1University of Oxford, Oxford, UK

Multiple sclerosis (MS) is a neurodegenerative disease characterised by a chronic inflammatory disorder associated with demyelination. MS can display a relapsing-remitting form of disease in which bacterial infection may play a role. The aim was to discover whether a systemic infection can reactivate a quiescent MS-like lesion in the brain by using MRI and immunohistochemistry. Early increase of regional cerebral blood volume (rCBV) surrounding the lesion provides an insight into systemic reactivation of MS-like lesions and revealed the reactivation of a previously quiescent CNS lesion can be induced by a systemic inflammatory response in a clinically-relevent model of MS.

                  2116.     Elucidating the Involvement of Spino-Olivocerebellar Pathways in Relapsing-Remitting EAE Using
                                 USPIO MRI

Madhavi Pai1, 2, Peter F. Bousquest2, Annette J. Schwartz2, Bradford L. Mcrae2, Christine M. Nelson2, Vincent P. Hradil1, Bryan F. Cox1, Gerard B. Fox1, Chih-Liang Chin1

1Abbott Laboratories, Abbott Park, Illinois, USA; 2Abbott Bioresearch Center, Worcester, Illinois, USA

Experimental autoimmune encephalitis (EAE) is a widely-used animal model of multiple sclerosis.  Recently, it has been demonstrated USPIO-enhanced MRI allows monitoring macrophage infiltration in vivo during the disease course of EAE.  Here, we investigated the occurrence of lesions and its implications on observed neurological deficits in relapsing-remitting EAE.  Results indicate USPIO-labeled lesions occurred in distinct CNS regions at various phases: brainstem (acute), no lesion (remission), and cerebellum and spinal cord (relapse), which reveal the involvement of spino-olivocerebellar pathways (cerebellar control of the limb posture and movement), in EAE.  Our data provide important insights into further understanding of this disease model.


Mixed Brain Pathology

Hall D                                   Thursday 13:30-15:30                                                                                                                                           

                  2158.     First Evidence That Frontal Lobe Choline-Containing Compounds Further Decrease and NAA Increases
                                During Early Abstinence in Alcohol Dependent Patients

Gabriele Ende1, Nuran Tunc-Skarka1, Derik Hermann1, Mareen Hoerst1, Sigi Walter1, Matthias Ruf1, Katharina Kraus1, Sabine Klein1, Karl Mann1

1Central Institute of Mental Health, Mannheim, Germany

Previous MRS studies have left the question how and when the Cho increase with alcohol consumption reverts into decreased Cho in abstinent alcoholics. We studied alcohol dependent patients early during detoxification and 2 weeks into abstinence, heavy alcohol drinkers and light to medium social drinkers at 3T. We see first evidence for our hypothesis that alcohol triggers non-linear dynamic changes of the Cho concentration: Cho initially increases with alcohol consumption but starts to decrease when alcohol abuse starts and significantly decreases during alcohol early abstinence. In contrast NAA shows a trend towards recovery within the first 2 weeks of abstinence.

                  2159.     Positive Correlation Between Absolute Choline Concentration with Alcohol Consumption in the Frontal
                                 White  Matter of Social Drinkers

Nuran Tunc-Skarka1, Mareen Hoerst1, Tim Wokrina1, 2, Gabriele Ende1

1Central Institute of Mental Health, Mannheim, Germany; 2now at Bruker BioSpin MRI GmbH, Ettlingen, Germany

It has been previously shown at a 1.5T scanner that in alcohol dependent patients after detoxification the Cho and its ratio to Cr is below-normal and increases with duration of abstinence. Now we aimed to replicate the correlation at a 3T scanner and also wanted to examine whether the correlation is caused by Cho concentration change or if it might be an effect of altered relaxation. We could corroborate a significant positive correlation between the Cho concentration in the FWM and alcohol consumption of the last two weeks (R = 0.823, p = 0.000).

                  2160.     Longitudinal Changes of Cerebral Gray Matter Perfusion in  Smoking and Non-Smoking Abstinent

Anderson Mon1, Timothy Craig Durazzo1, Stefan Gazdzinski2, Dieter Johannes Meyerhoff1

1UCSF, San Francisco, California , USA; 2CIND, San Francisco, California , USA

Synopsis: We used longitudinal perfusion MRI analysis to study cerebral gray matter perfusion changes in short-term abstinent alcoholics. The subjects were divided into cigarette-smoking alcoholics and non-smoking alcoholics. We observed that cerebral perfusion significantly increased in the non-smoking alcoholics over the first month of abstinence from alcohol but did not change in the smoking alcoholics. This suggests that cigarette smoking modulates cerebral perfusion recovery.

                  2161.     Diffusion Tensor Imaging of White Matter Abnormalities in Patients with Writer’s Cramp

Christine Delmaire1, Marie Vidailhet2, Maxime Descoteaux3, Demian Wassermann3, Frederic Bourdain4, Christophe Lenglet3, Sophie Sangla2, Axel Terrier5, Rachid Deriche3, Stéphane Lehéricy6

1Roger Salengro Hospital, Lille, France; 2Pitie Salpetriere Hospital, Paris, France; 3INRIA, Sophia Antipolis, France; 4Foch Hospital, France; 5Saint Antoine Hospital, Paris, France; 6University Pierre and Marie Curie-Paris 6, Paris, France

In this study, we investigated white matter abnormalities using diffusion tensor imaging (DTI) in 26 patients with focal hand dystonia compared with 26 healthy volunteers. SPM analysis showed that patients had increased FA values bilaterally in the area of the posterior limb of the internal capsule. FA abnormalities were located along the fiber tracts connected to the primary motor and sensory areas. These FA abnormalities were likely to reflect a specific disturbance of the white matter pathways that carry afferents and efferents to the primary sensory motor cortex.

                  2162.     Autonomic Dysfunction in Primary Biliary Cirrhosis (PBC) is Associated with Structural Brain
                                 Abnormalities,  Particularly in the Globus Pallidus
 [Not Available]

Kieren Grant Hollingsworth1, Ahmed M. El-Sharkawy1, Zia U. Khan1, Andrew M. Blamire1, Roy Taylor1, David E. Jones1, Julia L. Newton1

1Newcastle University, Newcastle Upon Tyne, UK

Autonomic dysfunction (AD) is a frequent finding in the autoimmune liver disease Primary Biliary Cirrhosis (PBC). This study examined structural lesions in 29 early stage PBC patients. Lesions were quantified on T2w images by two trained, independent observers according to the Scheltens scale. Autonomic function of the patients was assessed using a continuous beat-to beat Taskforce system. Total lesion load and lesion load in the globus pallidus was found to correlate with impaired baroreflex sensitivity. This is consistent with AD arising in PBC secondary to central effects. 

                  2163.     DTI Reveals Widespread White Matter Abnormalities in Myotonic Dystrophy Type 1 and Type 2 Populations

Daniel T. Franc1, Bryon Mueller, Joline Dalton, Cameron Naughton, John W. Day, Kelvin O. Lim

1University of Minnesota, Minneapolis, USA

Significant reductions in fractional anisotropy throughout cerebral white matter were observed in three Myotonic Dystrophy populations.

                  2164.     Correlation Between Regional Cerebral Volumes and Markers of Renal Function in Chronic Kidney Disease Patients

Joshua Francis Betz1, 2, Stephen L. Seliger, David Lefkowitz, Jiachen Zhuo, Shari R. Waldstein, Leslie I. Katzel, Rao P. Gullapalli

1University of Maryland Baltimore County, Baltimore, USA; 2University of Maryland, Baltimore, USA

Chronic Kidney Disease is associated with a number of factors implicated in structural and functional changes in the brain. The goal of the study is to elucidate relationships between clinical markers of renal function and structural changes related to aging. After controlling for the effects of age, clinical markers of renal function and cardiovascular health were related to lower region-specific measures of white and gray matter, and higher region-specific measures of cerebrospinal fluid in patients with Chronic Kidney Disease. Our research indicates that Chronic Kidney disease is related to morphological changes which are detectable through quantitative cranial MRI.

                  2165.     The [Ins]/[NAA] Ratio is Highly Correlated with Clinical Score in Huntington’s Disease, Likely Reflecting
                                Simultaneous Astrogliosis and Neuronal Loss

Myriam Chaumeil1, 2, Hélène Bataille1, Fawzi Boumezbeur1, Julien Valette1, Anne-Catherine Bachoud-Levi3, Philippe Hantraye2, Vincent Lebon1, 2, Pierre Brugières3

1NeuroSpin, Gif-sur-Yvette, France; 2MIRCen, Fontenay-aux-Roses, France; 3Hôpital Henry Mondor, Créteil, France

Metabolic abnormalities associated with Huntington’s Disease (HD) can be detected by NMR spectroscopy. Up to now 1H spectroscopy in HD has revealed almost systematic decreases in N-acetyl-aspartate and occasional increases in lactate and glutamate+glutamine. Although the glial marker myo-inositol could be a potential marker of degeneration, it has not been quantified yet in the adult form of HD. In this study short echo time 1H spectroscopy of the striatum was combined with LCmodel analysis in order to quantify myo-inositol in HD patients. We observed significantly elevated Ins in the striatum and strong correlation of the Ins/NAA ratio with clinical scores.

                  2166.     MRI T2 Hypointensity Load and Gray Matter Loss in Patients with Huntington’s Disease

Radu Serban Jasinschi1, Ahmet Ekin1, Adriaan van Es2, Mark Augustinus van Buchem2, Rene Engbers3, C. Damkat1, Caroline Jurgens2, Jeroen van der Grond2

1Philips Research, Eindhoven, Netherlands; 2Leiden University Medical Center, Leiden, Netherlands; 3Tass, Eindhoven, Netherlands

We investigate two MRI features computed in the Basal Ganglia (BG) of Huntington’s disease (HD) patients. One feature is the hypointensity load in T2-weighted (T2-w) images, and the other one corresponds to gray matter (GM) loss detected in T1-weighted (T1-w) images. We automatically select BG regions [2] given by a set of grid cells which define the region-of-interest (ROI). The T2-w hypointensity load within the ROI is computed by comparing image brightness with a threshold determined based on ROC curve analysis. The tissue segmentation was implemented based on a K-harmonic means clustering algorithm. We tested these two features on 28 subjects, 14 HD patients and 14 controls. We found out that, on average, the percentage of hypointense pixels in the BG is 3.95 times higher for HD patients compared to the controls. Also, the HD patients have 87 % less GM compared to controls, and about 8 % more white matter (WM), significant at p = 0.05 in t-test.

                  2167.     Voxel-Based Morphometry in the Mouse Brain: The R6/2 Huntington's Disease Model

Stephen J. Sawiak1, Guy Barnett Williams1, Nigel I. Wood1, A J. Morton1, T A. Carpenter1

1University of Cambridge, Cambridge, UK

Mouse models of disease are of increasing importance, in part because of the comparative ease of developing transgenic variants. Growing amounts of data make traditional analysis techniques such as histology prohibitive. Whilst MRI offers the potential for in-vivo investigation, the analysis problem is not yet fully addressed. Here we present our work in extending automated voxel-based morphometry techniques to the mouse brain, using the popular statistical parametric mapping (SPM) package. Although our work is applicable to any mouse brain model, here we present our methods and results from the R6/2 model of Huntington's disease with 87 three-dimensional, high resolution datasets.

                  2168.     Presymptomatic Detection of Brain Abnormalities in a Transgenic Ratmodel for Huntington' Disease Using
                                in Vivo Diffusion Tensor Imaging

Ines Blockx1, Nadja Van Camp, 12, Marleen Verhoye1, Johan Van Audekerke1, Huu Phuc Nguyen3, 4, Stephan Von Horsten3, Olaf Riess5, Annemie Van der Linden1

1University of Antwerp, Antwerp, Belgium; 2Commissariat a L'Energie Atomique - CEA, Orsay, France; 3Medical school of Hannover, Hannover, Germany; 4University of Tubingen , Germany; 5University of Tubingen, Germany

Diffusion tensor imaging has been widely used for detailed analyses of tissue morphology and pathology. Previous DTI studies have successfully demonstrated neurodegenerative changes in a lesion model of Huntington Disease. Transgenic models provide the advantage of mimicking the human pathology more closely and in addition they display a more progressive course of the disease. We aimed at revealing the first signs of neurodegeneration by investigating changes of microstructure and neuroconnectivity in young presymptomatic (2 months) transgenic animals. The results of this study will be highly valuable for pre-clinical screening as well as for the understanding of the specific underlying pathogenesis.

                  2169.     Imaging the Progression of Brain Atrophy in a Mouse Model of the Huntington’s Disease

Jiangyang Zhang1, Kenichi Oishi1, Qi Peng1, Qing Li1, Michael I. Miller2, Susumu Mori1, Wenzhen Duan1

1Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; 2Johns Hopkins University, Baltimore, Maryland, USA

We studied the progression of brain atrophy in R6/2 mice, a model of Huntington’s disease, using in vivo longitudinal MRI. High resolution images captured macroscopic changes in brain morphology from three weeks to 12 weeks after birth in the same animals. Quantitative analysis revealed atrophy in the striatum, motor and pimiform cortex, as well as enlargement of the lateral ventricles in 5 week old mice. Longitudinally, the rates of brain atrophy were not uniform. Our results suggested that atrophy in the striatum was most active at around 5 weeks old.

                  2170.     Voxel-Based Morphometry Study in Restless Legs Syndrome (RLS): Volumetric Increase in Multiple
                                 Brain Regions

Byeong-Yeul Lee1, Jeffrey Vesek1, Shoaib Alam1, James R. Connor1, Qing X. Yang1

1Penn State Univeristy College of Medicine, Hershey, Pennsylvania, USA

Restless leg syndrome (RLS) is a sensory-motor disorder coupled with iron deficiency in the RLS brain. It is not known whether or not RLS brain volume is different from normal control. We hypothesize that insufficient iron concentration in RLS may contribute to the global regional change. To test our hypothesis, we conducted a voxel-based morphometry study on RLS. Our data demonstrate that a significant volumetric increase was found in the gray and white matter in RLS. Thus, we may speculate that iron deficiency contribute to the increase in volume in RLS patients compared to controls.

                  2171.     Decreased R2 and Increased Concentrations of Multiple Cerebral Metabolites in the Restless Legs
                                 Syndrome (RLS) Brain: Exploring Iron Deficiency Consequence in RLS

Byeong-Yeul Lee1, Jeffrey Vesek2, Elana Farace2, Shoaib Alam2, James R. Connor2, Qing X. Yang2

1Penn State University College of Medicine, Hershey, Pennsylvania, USA; 2Penn State Univeristy College of Medicine, Hershey, Pennsylvania, USA

Restless legs syndrome (RLS) is a neurological disorder in which iron deficiency in central nervous system is a contributing factor. However, in vivo human studies which link iron deficiency to brain metabolism in RLS brain have not been previously reported. Using in vivo MRI and proton MRS, we investigated the effect of insufficient iron contents on the neurochemical metabolism in RLS.The result showed that decreased in R2 values and increase in various metabolite concentrations in the RLS brain. Thus, the findings of our study may provide insight into neurochemical derangements resulting from iron deficiency in RLS.

                  2172.     Metabolic Changes in the Thalamus of Restless Legs Syndrome Patients: Preliminary 1H-MRS Findings

Giovanni Rizzo1, 2, Pasquale Montagna1, Caterina Tonon1, Roberto Vetrugno1, Claudia Testa1, Giuseppe Plazzi1, Federica Provini1, Bruno Barbiroli1, Raffaele Lodi1

1University of Bologna, Bologna, Italy

Restless legs syndrome (RLS) is a common disorder in the general population. The pathophysiology of RLS is poorly understood. Recent studies have suggested a potential thalamic involvement. We performed a 1H-MRS study in patients with RLS and normal controls selecting a volume of interest at the level of the medio-posterior region of the thalamus, in order to identify metabolic changes in this structure. In RLS patients we detected a significant reduction in NAA/Cr and in the absolute concentration of NAA. Our preliminary spectroscopic data confirm a thalamic involvement in RLS patients.

                  2173.     Global Brain Iron Deficiency in Restless Legs Syndrome Examined by an Increase of T2-Values  [Not Available]

Jana Godau1, Katharine Schweitzer1, Adriana Di Santo1, Daniela Berg1, Uwe Klose1

1University Hospital Tuebingen, Tuebingen, Germany

Restless Legs Syndrome (RLS) is a disorder, for which brain iron deficiency is suspected. In this study with RLS patients, we examined alterations of the T2 relaxation, which is expected to occur with reduced iron content. T2-values were calculated from 2 echoes from a Turbo spin-echo sequence. Circular ROIs were bilaterally placed in ten selected regions. In every examined brain region the average T2 value histogram plots were remarkably shifted to higher T2 intensities in the RLS patient group. Increased T2 values in RLS patients compared to controls suggest decreased iron content in all examined brain regions.

                  2174.     Factor Analysis Reveals Metabolic Differences in Macaques with SIV/AIDS and Encephalitis

Margaret R. Lentz1, Vallent Lee1, Susan V. Westmoreland2, Eva-Maria Ratai1, Elkan F. Halpern3, R. Gilberto Gonzalez1

1Massachusetts General Hospital, Charlestown, USA; 2New England Primate Research Center, Southborough, USA; 3Massachusetts General Hospital, Boston, USA

1H MRS provides multivariate data on metabolites in the HIV-infected brain, and can benefit from the use of factor analysis (FA). We applied FA to identify patterns in the metabolic processes underlying the pathogenesis of neuroAIDS, using frontal cortex extracts from SIV-infected macaques moribund with AIDS. One factor could discern between SIV/AIDS animals and healthy controls. Another factor could distinguish animals with encephalitis, and was significantly different across classifications of encephalitis severity. We demonstrate the strengths of FA and discuss the implications that the data raise regarding the analysis of in vivo MRS.

                  2175.     Glutamate is Reduced in the Frontal Lobe of HIV Patients

Napapon Sailasuta1, Kimberly Shriner2, Brian Ross1

1Huntington Medical Research Institutes, Pasadena, California , USA; 2Huntington Hospital, Pasadena, California , USA

First report of direct measurement of brain glutamate concentrations in HIV patients

                  2176.     Increased GABA in Basal Ganglia of HIV-Infected Adults Measured by 1 H MRS

Kevin Wayne Waddell1, David W. Haas1, Robin Avison1, Parham Zanjanipour2, Subechhya Pradham3, John C. Gore1, Rebecca Basham, Kirsten L. Haman1, Malcolm J. Avison1

1Vanderbilt University, Nashville, USA; 2University of Kentucky, Lexington, USA; 3Vanderbilt, Nashville, USA

The basal ganglia are rich in GABA innervations and show evidence of HIV within weeks of infection and bear a high viral burden. We therefore hypothesized that altered GABA metabolism in this region may be an early consequence of HIV infection and used a robust and reproducible GABA editing protocol to compare basal ganglia GABA levels in chronically infected, relatively immunocompetent, neurocognitively intact HIV+ patients who were not receiving antiretroviral treatment, with those of presumed non-infected control subjects. In this small cohort, GABA levels in the HIV+ group were approximately 150% higher than in normal (healthy) volunteers.

                  2177.     Lower NAA Correlates with CD16+ Monocyte Expansion During Primary/Early HIV Infection

Margaret R. Lentz1, Woong-Ki Kim2, Vallent Lee1, Kenneth Williams3, Eric Rosenberg4, R. Gilberto Gonzalez1

1Massachusetts General Hospital, Charlestown, USA; 2Eastern Virginia Medical School, Norfolk, USA; 3Boston College, Chestnut Hill, USA; 4Massachusetts General Hospital, Boston, USA

1H MRS has demonstrated that brain metabolism changes in chronic HIV infection, and animal studies have suggested that neuronal injury and inflammation may also be occurring in primary (acute) infection. We report the validation of metabolic changes during primary/early HIV infection, and their correlation with immunologic factors. Subjects with primary/early HIV infection had lower levels of neuronal marker NAA and a greater proportion of monocytes in their blood. Further analysis shows that neuronal injury is correlated to the expansion of a specific subset (CD16+) of monocytes, signifying the possible establishment of the brain as a viral reservoir early during infection.

                  2178.     An MRI Study of Rat Model of Cryptococcal Meningo-Encephalitis

Ami Pai1, Rohit Sood1

1University of New Mexico, Albuquerque, New Mexico, USA

C. neoformans meningoencephalitis (CNME) is the commonest fungal infection associated with the death of HIV infected patients. Newer pharmaceutical based treatment options for CNME require testing in animal models. A critical step in the evaluation of newer drug treatments is to be able to assess drug efficacy in the same animal over time. MRI provides the optimal framework for performing drug studies in rat models due to its non-invasive nature and ability to follow the longitudinal course of the disease in the same animal. In this study, MRI has been used to characterize a rat model of CNME and the MRI results have been compared with histological findings. Initial results suggest that intracerebral lesions due to CNME were well visualized using MRI. Additionally, MRI results were in good agreement with findings from the histopathological staining method.

                  2179.     Quantitative Analysis of Metabolic Alterations in a Mouse Model of Neuro-Inflammation Using in Vivo
 MR Spectroscopy

Adriana Bucur1, Arlette Bernard2, Cristina Cudalbu1, Pascale Giraudon2, Danielle Graveron-Demilly1, Hélène Ratiney1, Sophie Cavassila1

1CNRS UMR 5220, Inserm U630, INSA-Lyon, Université de Lyon, Université Lyon 1, Villeurbanne, France; 2Inserm U842, Faculté Laennec, Lyon, France

Quantification of the NMR spectroscopic observable metabolites can provide considerable biochemical information and can help clinical investigators in understanding the role of metabolites in normal and pathological conditions associated with neuro-inflammation disease. The aim of the present study was to monitor the metabolic changes in a mouse model of neuro-inflammation. Significant concentration changes of NAA, Lac and Tau were detected from the early stages of the neuro-inflammation. The decrease of NAA has been described in neuronal insults and may sign a neuronal suffering virus-induced. Taurine has been thought to be essential for the development and survival of neural cells and to protect them under cell-damaging conditions and its release could constitute an important mechanism against excitotoxicity. High concentration of Lactate may indicate alterations of oxidative phosphorylation seen in pathological condition of anaerobic metabolism. In conclusion, MRS is useful to detect metabolic dysfunctions from the early stages and investigate the outcome of neuro-inflammation disease.

                  2180.     New Perspectives for Vascular Dementia Patients at 7T!

Jens Matthias Theysohn1, 2, Oliver Kraff1, 2, Stefan Maderwald1, 2, Wolfgang P. Becker1, 2, Markus Barth1, 3, Lena Schaefer1, 2, Susanne C. Ladd1, 2, Michael Forsting1, 2, Mark E. Ladd1, 2, Elke Ruth Gizewski1, 2

1University Duisburg-Essen, Essen, Germany; 2University Hospital Essen, Essen, Germany; 3F.C. Donders Centre for Cognitive Neuroimaging, Nijmegen, Netherlands

Introduction of 7 Tesla MRI systems  for human imaging is an important development which might provide potential for further perfecting clinical diagnostics. The purpose of this study was to evaluate the value of 7 Tesla MRI in the assessment of cerebrovascular alterations as seen in vascular dementia (VD). Eight patients with known microangiopathy and/or microbleeds were examined. Improved detection of microbleeds coupled with good visualization of white matter lesions at 7T might have significant impact on the early diagnosis of cerebrovascular patients, and provide additional criteria to optimize antithrombotic treatment.

                  2181.     Assessment of BBB Damage in Patients with VCI Using MRI

Saeid Taheri1, Heiko Neeb2, N J Shah2, Gary Rosenberg1, Rohit Sood1

1University of New Mexico, Albuquerque, New Mexico, USA; 2Institute for Medicine, Julich, Germany

Vascular Cognitive Impairment (VCI) is a neurological disorder characterized by dementia with histopathological evidence of cerebrovascular disease and neuroimaging findings of multiple infarctions and white matter (WM) abnormalities. It has been postulated the white matter abnormalities in these patients may be associated with BBB damage. In this study, an MRI technique has been used to quantify BBB damage by measuring BBB permeaility. The technique has been developed and successfully implemented in an animal model of stroke and in this study has been used to accurately quantify BBB damage in patients with VCI. Initial results suggest that white matter lesions are associated with high permeability and are regions of active BBB damage. This study is an example of the role of translational research in improving patient care.

                  2182.     Detection of Stroke and Microbleeds Using Susceptibility Weighted Imaging

Muhammad Ayaz1, 2, Ewart Mark Haacke1, 2, Alexander S. Boikov1, Elena S. Manova2, April Dickson3, Cindy Dickson3, Grant McAuley3, Wolff Mayer Kirsch3, Daniel Kido3, Floyd F. Peterson3, William G. Britt3, James P. Larsen3

1The MRI Institute for BioMedical Research, Detroit, USA; 2Wayne State University, Detroit, USA; 3Loma Linda University, Loma Linda, USA

Microbleeds (MBs) are associated with vascular dementia (VaD) and cerebral amyloid angiopathy (CAA). These MBs are small hemorrhages resulting from vessel wall injury from CAA. Patients with VaD have a higher risk of developing MBs. Susceptibility Weighted Imaging (SWI), a high resolution gradient echo imaging technique, is sensitive to hemosiderin even for arteriole bleeds and has revealed MBs much smaller than 5 mm (above which they are usually referred to as macrobleeds). There is also an association between MBs and stroke. The purpose of this paper is to examine the presence of developing major bleeds over time for Alzheimer patients

                  2183.     Defining and Categorizing Microbleeds (MB) in Neurodegenerative Disease Using SWI

Muhammad Ayaz1, 2, Ewart Mark Haacke1, 2, Alexander S. Boikov1, Wolff Mayer Kirsch3, Daniel Kido3

1The MRI Institute for BioMedical Research, Detroit, USA; 2Wayne State University, Detroit, USA; 3Loma Linda University, Loma Linda, USA

Microbleeds(MB) in aging is gaining more and more attention. Most studies include a large number of subjects and are snapshots of variety of ages and conditions. These studies discuss the roles of cerebral amyloid angiopathy(CAA), intracranial hemorrhage(ICH) and signal-hyperintensites. The purpose of the current study is to use Susceptibility Weighted Imaging(SWI) to follow a set of 6 subjects and to find and categorize the types of MB that occur in these subjects. No previous study clearly defines when to call a signal loss a microbleed (especially with MB as small as a few pixels) nor has anyone categorized these MBs 

                  2184.     DTI Analysis of White Matter Deficits in Frontotemporal Lobular Dementia  [Not Available]

Jane Asmuth1, Hui Zhang, Murray Grossman, James Gee

1University of Pennsylvania, Philadelphia, Pennsylvania, USA

Diffusion tensor imaging is used to compare underlying white matter differences between three patient subgroups of frontotemporal lobular dementia

                  2185.     Regional Brain Metabolite Pattern in Fronto-Temporal Dementia

Sanjeev Chawla1, Sumei Wang1, John H. Woo1, Lauren B. Elman1, Leo F. McCluskey1, Elias R. Melhem1, Murray Grossman1, Harish Poptani1

1University of Pennsylvania, Philadelphia, Pennsylvania, USA

We performed multivoxel magnetic resonance spectroscopy on fifteen patients with frontal-temporal dementia (FTD) and six controls to assess metabolic abnormalities in prefrontal cortex (PFC) and motor cortex (MC) and parietal cortex (PC). A significant reduction in N-acetyl aspartate (NAA) and creatine (Cr) and increase in choline (Cho) and myo-inositol (mI) was observed from the PFC of patients compared to controls. Significantly lower NAA and higher Cho concentrations were also observed in MC of patients. Within patients, both MC and PFC exhibited significantly lower NAA and higher Cho compared to PC. Only PFC had significantly lower Cr and significantly higher mI compared to PC.

                  2186.     Altered Functional Connectivity in Aged Rat Model of Postoperative Cognitive Dysfunction

Peng Xie1, 2, Tian Yu1, 2, Xiao-yun Fu1, 2, Ye Tu1, 2, Su Lui2, Xu-na Zhao3, Hua-fu Cheng4, Xiao-qi Huang2, Ti-jing Zhang2, Xiu-li Li2, Qiang Yue2, Dong-ming Li2, Qi-yong Gong2, 5

1Affiliated Hospital of Zunyi Medical College, Zunyi, People's Republic of China; 2Huaxi MR Research Center (HMRRC),West China Hospital of Sichuan University, Chengdu, People's Republic of China; 3Philips Medical System, Beijing, People's Republic of China; 4School of Science and Technology, University of Electronic Science and Technology, Chengdu, People's Republic of China; 5Division of Medical Imaging, Faculty of Medicine, University of Liverpool, UK

Postoperative cognitive dysfunction (POCD) is a common complication occurs after cardiac and major non-cardiac surgery with general anesthesia in the elderly, but its causes and mechanism remains unclear to date. Present study aims to use resting-state fMRI to explore changes of the functional connectivity in animal model of POCD on aged rats. Our findings implied that the change of functional connectivity in the related cortex and hippocampus maybe one of the underlying causes for the cognitive deficit presented after surgery. Further study on human beings will help to clarify the similar clinical profiles in POCD.

                  2187.     Voxel-Based T2 Relaxometry Detects Brain Injury in Autonomic and Cognitive Regulatory Areas
                                 in Patients with Heart Failure

Rajesh Kumar1, Mary A. Woo1, Paul M. Macey1, Stacy L. Serber1, Ronald M. Harper1

1UCLA, Los Angeles, USA

Heart failure (HF) patients often show severe autonomic, emotional, and cognitive deficits which could only result from brain alterations; yet, there are few reports describing brain injury in this group. We assessed neural injury in HF and controls using voxel-based T2 relaxometry. Higher T2 relaxation values in HF, indicating areas of injury, emerged in hypothalamus, solitary tract nucleus, hippocampus, cerebellum, caudate, thalamus, anterior fornix, corpus callosum, cingulate, and insula. The affected structures are essential to maintain autonomic, mood and cognitive functions. The mechanisms underlying damage are unclear, but may result from ischemic or hypoxic processes.

                  2188.     White Matter Alterations in Callosal Agenesis: A Diffusion Tensor Imaging Study

Michael Wahl1, 2, Elliott H. Sherr1, Anthony James Barkovich1, Steven W. Hetts1, Mari Wakahiro1, Pratik Mukherjee1

1University of California, San Francisco, San Francisco, California , USA

                 2189.     In Vivo MRI and MRA at 9.4T Show How (LT) α–TNF Receptor 2 or LTβ Receptor Deficiency on Mutant
                              Mice Affects the Development of Experimental Malaria

Dieudonnée Togbe1, Paulo Loureiro de Sousa2, Mathilde Fauconnier1, Victorine Boissay1, Lizette Fick3, Stefanie Scheu4, Klaus Pfeffer4, Robert Menard5, Georges Grau6, Laurent Renia7, Bernhard Ryffel1, Valérie Quesniaux1, Bich-Thuy Doan8, Jean-Claude Beloeil2

1University of Orléans, Orléans, France; 2CNRS, France; 3Institute of Infectious Disesase, Cape Town, South Africa; 4University of Dusseldorf, Germany; 5Pasteur Institute, Paris, France; 6The University of Sydney, Australia; 7Institut Cochin, France; 8CNRS, Gif sur Yvette, France

Cerebral malaria is a frequent cause of death in children infected with Plasmodium falciparum, which is characterized by the sequestration of parasitized erythrocytes in cerebral blood vessels.In this work, investigations on experimental cerebral malaria (ECM) revealed that the lymphotoxin α (LTα) and signaling through TNFR2 are critical. Indeed, LTβR and LTαβ deficient mice, did not develop the neurological signs contrary to C57BL/6J wild type and TNF deficient mice.T2 and angiographic MRI were used to verify the lack of ischemia and microvascular pathology in TNF, LTαβ and LTβR deficient malarial mice. The results were validated by histological studies.


MRI/MRS of Psychiatric Disease

Hall D                                   Thursday 13:30-15:30                                                                                                                                           

                  2248.     Learning Potential in Schizoprenia is Related to Neuronal Integrity of the Anterior Cingulate Cortex as
                                Measured by Proton MR Spectroscopy

Harald Kugel1, Jochen Bauer1, Ansgar Siegmund1, Anette Kersting1, Volker Arolt1, Thomas Suslow1, Walter Heindel1, Anya Pedersen1, Patricia Ohrmann1

1University of Muenster, Muenster, Germany

Impairment in cognitive domains has been described in patients with schizophrenia. In this study learning potential was assessed in 35 schizophrenic patients and 23 healthy controls using a dynamic version of the Wisconsin Card Sorting Test (WCST). Cognitive performance was related to cerebral metabolites measured with single voxel proton MRS of the dorsolateral prefrontal cortex (DLPFC) and the anterior cingulate cortex (ACC). In schizophrenic patients a positive correlation between learning potential and NAA levels of the ACC, whereas in healthy controls a correlation between learning and NAA levels of the DLPFC was observed.

                  2249.     Functional MRI of Choice Reaction Time in Chronic Schizophrenia and First-Degree Relatives

David Paul McAllindon1, 2, Alan H. Wilman1, Scot E. Purdon1, 2, Philip G. Tibbo1, 2

1University of Alberta, Edmonton, Canada; 2Bebensee Schizophrenia Research Unit, Edmonton, Canada

Slower and more variable reaction time may be a specific cognitive deficit of schizophrenia.  This study examines differences in brain activations between healthy volunteers, men with chronic schizophrenia, and first-degree relatives of a person with schizophrenia while the subject performs a visual 2-choice reaction time task.

                  2250.     Glutamatergic Changes in First Episode Schizophrenia After Long Term Assessment

Naoko Aoyama1, 2, Jean Theberge1, 3, Dick J. Drost1, Richard WJ Neufeld1, Rahul Manchanda1, Maria Densmore2, Betsy Schaefer1, Peter C. Williamson1

1University of Western Ontario, London, Canada; 2Lawson Health Research Institute, London, Canada; 3, St. Joseph’s Health Care, London, Canada

Schizophrenia is a life long disease with an unknown cause and mechanism.  One possible explanation is the glutamate hypothesis, which suggests that decreased NMDA receptor increases glutamate leading to neuronal toxicity.    A five year longitudinal proton MRS study on never treated schizophrenics has found a significant decrease in NAA, glutamate, and creatine between 10 months and 60 months after beginning treatment in the left Thalamus.  The changes in both NAA and glutamate between 10M and 60M correlated inversely with the length of illness. These results may indicate the neuronal degeneration occurs early in schizophrenia.

                  2251.     MRI for Assessment of BBB Functioning in CNS Disorders and Induced BBB Disruption

David Israeli1, Dianne Daniels2, Yiftach Roth2, David Last2, Yair Bar2, Talila Volk1, Yael Mardor2

1Weizmann Inst, Israel; 2Sheba Medical Center, Ramat-Gan, Israel

We have developed a novel imaging tool based on dynamic contrast MRI enabling real-time depiction/quantification of local/spread BBB abnormalities in humans, with high sensitivity to BBB functioning. 20 patients and controls were included in the study so far. The results suggest a direct correlation between BBB abnormality patterns depicted by our methodology and clinical manifestation in Schizophrenia, headache disorders and BBB disruption induced by Isosorbide dinitrate. This methodology may provide a new aspect in the diagnosis/staging of CNS disorders. In addition, it may be applied for real time assessment of BBB disruption induced for therapeutic purposes such as drug delivery.

                  2252.     Joint Source Based Morphometry to Identify Sources of Gray Matter and White Matter Relative
                                Differences in Schizophrenia Versus Controls

Lai Xu1, 2, Godfrey Pearlson3, 4, Vince D. Calhoun1, 2

1The MIND institute, Albuquerque, New Mexico, USA; 2The University of New Mexico, Albuquerque, New Mexico, USA; 3Olin Neuropsychiatry Research Center, Institute of Living, Hartford, USA; 4Yale University School of Medicine, New Haven, USA

In this study, we use a novel approach, joint source based morphometry (jSBM), to identify the joint sources networks of gray matter and white matter to reveal differences between schizophrenia patients and healthy controls. JSBM is a multivariate approach for image fusion among different types of structural MRI images. Our approach provides a way to jointly identify changes in both gray and white matter and may prove to be a useful tool to study the brain.

                  2253.     Cortical Glutamate is Linked to Reward Related Ventral Striate Activity – a Study Combining FMRI
                                and MRS at 3 T

Florian Schubert1, Ruediger Bruehl1, Frank Seifert1, Jan Reuter2, Martin Voss2, Theresa Dembler2, Nicola Klein2, Yehonala Gudlowski2, Corinna Pehrs2, Juergen Gallinat2, Andreas Heinz2

1Physikalisch-Technische Bundesanstalt, Berlin, Germany; 2Charite Universitätsmedizin, Berlin, Germany

Processing of rewarding stimuli increases firing rate of dopamine neurons in the ventral striatum (VS), which is disturbed in diseases with dysfunctional reward behavior, eg schizophrenia. Interactions between dopamine and glutamate (Glu) may play an important role in reward processing. We examined VS activity (BOLD contrast during reward processing) and Glu in the anterior cingulate (AC) in healthy subjects at 3T in combined fMRI-MRS experiments. VS activation was negatively correlated with AC Glu concentration. Our findings indicate a relationship between frontal glutamate and activation of the ventral striatum and thus indirectly visualize an interaction of dopaminergic and glutamatergic neurotransmission.

                  2254.     Interhemispheric Connectivity in Schizophrenia and Bipolar I Disorder: A Probabilistic Tractography Study

Christopher A. Chaddock1, Gareth J. Barker1, Robin M. Murray1, Colm McDonald2

1Institute of Psychiatry, London, UK; 2National University of Ireland, Galway, Ireland

Background: A single cortical area has not been identified that can explain the wide range in symptoms identified in psychotic disorders, therefore a hodological approach, which investigates the pathways that link major cortical and subcortical structures may prove more beneficial. Method: Interhemispheric connectivity was assessed in schizophrenia and bipolar disorder using probabilistic tractography. Results: Significantly reduced FA was detected in the splenium of corpus callosum (but not genu) within the core of the tract in bipolar disorder patients. No significant reductions of FA were detected in schizophrenia. Conclusion: Abnormalities in white matter coherence may be greater in bipolar disorder than schizophrenia.

                  2255.     Schizophrenia But Not Bipolar Adolescent Offspring Show Developmentally Mediated Deficits in Prefrontal
                                Structure and Function
 [Not Available]

Dhruman Goradia1, Diana Mermon1, Debra Montrose1, Boris Birmaher1, Matcheri Keshavan, 12, Vaibhav Diwadkar, 12

1Western Psychiatric Institute and Clinic, Pittsburgh, Pennsylvania, USA; 2Wayne State University, Detroit, Michigan, USA

We hypothesized that relative to controls (HC), schizophrenia (HRS) but not bipolar offspring would show developmentally related deficits in prefrontal structure and function. Region of interest, voxel based analyses of frontal lobe on three age and gender matched groups HC, HRS and HRB with intra-group median splits by age were performed. Spatial working memory addressed frontal lobe function. Only the HRS group showed greater decreases in gray matter density in older adolescents. Corresponding significant decrements in spatial working memory were noted. Results are consistent with exaggerated gray matter pruning in schizophrenia and suggest vulnerability of the frontal cortex in risk for schizophrenia.

                  2256.     fMRI Guided 31P Spectroscopy in Bipolar Disorder

Wen-Jang Chu1, 2, Martin Lamy1, James Eliassen1, Xin Wang1, Stephen Strakowski1, JingHuei Lee1

1Univ. of Cincinnati, Cincinnati, USA

The combined approach of fMRI and 31P spectroscopy is proposed to study bipolar disorder patients. A novel behavioral task, Balloon Analogue Risk Task, was used for fMRI study to identify brain regions associated with behavior impairments. Three-dimension 31P MRSI data were used to measure brain chemistry in the brain regions vulnerable to risk taking. Our preliminary result showed that PCr/ATP ratio in the cerebellar vermis of bipolar patients decreased as compared with healthy subjects. However, other regions such as the anterior cingulate cortex, left/right inferior frontal gyrus, left/right thalamus showed hyperactivity in fMRI but no significantly abnormal in 31P metabolites.

                  2257.     Tract-Based Spatial Statistics (TBSS) of Diffusion Tensor Imaging Data in Bipolar Disorder:
        Abnormalities of the Neurocircuitry

Ping-Hong Yeh1, Serap Monkul-Nery, Mark A. Nicoletti, Fabiano G. Nery, Giovana B. Zunta-Soares, John Li, Jack Lancaster, Jair C. Soares

1University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA

Microstructural abnormalities of neurocircuitry in unmedicated bipolar disorder (BD), characterized by low fractional anisotropy in bodies and genu of corpus  callosum, anterior cingulum, superior corona radiata and anterior limb of internal capsule, were demonstrated by using tract-based spatial statistics (TBSS) of diffusion tensor imaging data. These findings provide direct evidence of  compromised integrity of the inter-hemispheric connections, fronto-limbic and cortico-striatal circuits in BD. These abnormalities could be partially responsible for deficiencies in executive functions, behavioral regulation and impulse control  commonly described in BD.

                  2258.     Quantitative FA Analysis Based on VBM and Probabilistic Tractography Connectivity Between 
                                Treatment-Resistant Patients and Treatment-Responsive Patients with Major Depressive Disorder

Wu Li1, George Andrew James1, Helen S. Mayberg2, Xiaoping Hu1

1Georgia Tech and Emory University, Atlanta, USA; 2Emory University School of Medicine, Atlanta, USA

Treatment-resistant depression is a severely disabling disorder. Up to 20% of depression patients fail to respond to standard interventions. To study microstructual alterations of cerebral white matter between treatment-resistant and treatment-responsive depression patients, we proposed an approach that quantifies fractional anisotropy changes between these two groups based on VBM and probabilistic tractography connectivity using diffusion tensor imaging. Results indicate treatment-resistant patients have less diffusivity and fiber integrity in thalamus and subgenual anterior cingulate regions than treatment-responsive patients. This robust finding may aid future studies of microstructural changes associated with clinical severity, as well as aid future diagnosis or treatment.

                  2259.     Resting State FMRI in Geriatric Depression Before and After Treatment

Minjie Wu1, Robert Tamburo1, Meryl Butters1, Charles F. Reynolds, III1, Howard J. Aizenstein1

1University of Pittsburgh, Pittsburgh, Pennsylvania, USA

The low-frequency (0.01-0.1 Hz) fluctuations in BOLD signal at resting-state have been hypothesized to reveal the baseline of brain activity. In this study, we compared the default-mode functional connectivity in elderly healthy controls, elderly patients with late life depression (LLD), and patients after antidepressant treatment of LLD. Our results show the default-mode functional connectivity of patients with LLD is significantly lower than that of elderly controls in the prefrontal cortex region for a corrected p < 0.05 and there is no statistically significant differences between the patients after treatment and patients before treatment or between patients after treatment and controls.

                  2260.     White Matter Changes in Obsessive-Compulsive Disorder Revealed by Diffusion Tensor Imaging

Ivanei Edson Bramati1, Leonardo F. Fontenelle, 12, Jorge Moll1, Ricardo de Oliveira-Souza1, 3, Fernanda Tovar-Moll1

1LABS-D'Or Hospital Network, Rio de Janeiro, Brazil; 2Institute of Psychiatry - Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; 3Gaffree e Guinle University Hospital, Rio de Janeiro, Brazil

Previous studies addressing the involvement of the white matter (WM) tracts in obsessive-compulsive disorder (OCD) have shown contradictory findings. This study applied diffusion tensor imaging to investigate WM changes in patients with OCD, as compared to healthy volunteers. Whole brain, tract-based spatial statistic and a priori selected regions of interest showed decreased fractional anisotropy and increased diffusivity in regions of the internal capsule and tracts of the limbic system. These findings are in accordance to previous studies and also point to the possible involvement of additional WM structures in OCD.

                  2261.     Emotional Arousal and Regulation in Adolescents Prenatally Exposed to Cocaine: An FMRI Study

Priya Santhanam1, Zhihao Li1, Claire Coles1, Mary Ellen Lynch1, Stephan Hamann1, Xiaoping Hu1

1Emory University, Atlanta, Georgia, USA

Prenatal cocaine exposure (PCE) causes disrupted emotional arousal regulation. In this study, emotional network activity and emotion regulation during a working memory task were examined in PCE adolescents using fMRI. Several regions of an emotional network were found to have higher baseline functional connectivity with the right amygdala in PCE subjects. Also, a higher memory load during task led to reduced amygdala activity in controls but not in PCE. Results suggest that the emotional network in PCE subjects is more active in the resting state and high activity level continues even with increased cognitive demand, possibly causing impaired attentional control.

                  2262.     Prenatal Cocaine Exposure Alters Default Mode Brain Activity: Functional and Resting State MRI Evidence

Zhihao Li1, Priya Santhanam1, Claire D. Coles2, Mary Ellen Lynch2, Stephan Hamann2, Xiaoping Hu1

1Emory Univ./Georgia Tech., Atlanta, Georgia, USA; 2Emory Univ., Atlanta, Georgia, USA

Prenatal cocaine exposure alters the "default mode" brain network activity, which may be part of the neurobiological basis of the teratogenic effect.

                  2263.     Functional Connectivity of Alexithymia in Heroin Addicts

chunming Xie1, 2, chunming Xie3, guohua Bi1, guangxiong Liu1, liping Fu1, yongcong Shao1, jun Xie2, wenjun Li2, zhilin Wu2, lin Ma4, zheng Yang1, shi-jiang Li2

1Beijing Institute of Basic Medical Science, Beijing, People's Republic of China; 2Medical College of Wisconsin, Milwaukee, USA; 3Medical College of Southeast University, Nanjing, People's Republic of China; 4Department of Radiology, PLA Hospital, Beijing, People's Republic of China

Alexithymic individuals have difficulty in recognizing and describing emotions. Although recent neuropsychological and neuroimaging data have addressed the fundamental role of the amygdala in mediating emotion in different diseases, such as depression, schizophrenia, and cocaine abuse,to the best of our knowledge, the neural processing of an alexithymic response in heroin-dependents has not been examined. To this end, we utilized resting-state functional connectivity MRI to determine changes in functional connectivity and investigate the neural basis of the alexithymia in heroin addicts

                  2264.     Impaired Decision-Making in Abstinent Methamphetamine Addicts: Iowa Gambling Task  [Not Available]

Jae-Jun Lee1, Hui-jin Song1, Joo-hyun Kim1, Seung-Tae Woo1, Hee-Kyung Kim1, Ji-Ae Park1, Hui-joong Lee, Yang-Tae Kim2, Yongmin Chang1

1Kyungpook National University, Daegu, Republic of Korea; 2Bugok National hospital, Republic of Korea

Substance dependent individuals (SDI) are characterized by repeated substance use and loss of control, despite the presence of negative consequences. This study assessed temporal response of neural activation in healthy subject and substance dependent individuals (SDI) using the BOLD functional magnetic resonance imaging (fMRI) and Iowa Gambling task(IGT). The results of normal subject showed the activity in right dorsolateral prefrontal cortex (DLPFC) and the right medial superior frontal cortex during ambiguous decision-making Risky decision making on the other hand was more associated with activity in right orbitofrontal cortex (OFC), ventromedial anterior cingulated cortex (ACC), and cerebellum. Compared to normal subjects, SDI failed to activate ventromedial cortex and DLPFC. These differences of frontal activation area were accompanied by an increased susceptibility to the influence of immediately preceding trial outcome.

                  2265.     Brain Glutamate and Empathy. a Proton MRS Study at 3 Tesla

Florian Schubert1, Frank Seifert1, Christiane Montag2, Jürgen Gallinat2, Andreas Heinz2

1Physikalisch-Technische Bundesanstalt, Berlin, Germany; 2Charite Universitätsmedizin, Berlin, Germany

Empathy is an essential element of human behavior. Dysfunctions of empathy and mentalizing have been seen as a basal feature of psychopathological syndromes in severe mental disorders. We investigated the relationship between self-rated dimensions of empathy as measured by the Interpersonal Reactivity Index, and concentrations of cerebral glutamate determined by 1H-MRS at 3 Tesla in 17 healthy subjects. Glutamate concentration in the dorsolateral prefrontal cortex was predicted by empathy factor 'perspective taking'. DLPFC glutamate level and 'perspective taking' score showed a significant negative correlation. These data suggest a possible involvement of cerebral glutamate in cognitive empathy.

                  2266.     Clinical Application of Low-Power 13C MRS Suited to Neuropsychiatric and  Frontal Brain Disorders

N. Sailasuta1, A L. Gropman2, L. Robertson3, K. Harris1, P. S. Allen4, B. Ross1

1Huntington Medical Resrearch Institutes, Pasadena, California , USA; 2Children's National Medical Center, USA; 3Spin Dynamics, South Pasadena, California , USA; 4University of Alberta, Edmonton, Canada

Neuropsychiatric disorders can be studied with 13C MR spectroscopy only if the regions of brain implicated fall into those distant from the eyes, This has skewed MR research in these important diseases, because proton decoupling power exceeds SAR.  New sequence solves this problem - as shown in this Abstract.

                  2267.     White Matter Abnormalities in Tardive Dyskinia: A Diffusion Tensor Image Study

Kun-Hsien Chou1, I-Yun Chen2, Pin-Yi Chiang3, Ya-Mei Bai4, Tung-Ping Su4, Woei-Chyn Chu1, Ching-Po Lin2, 3

1Institute of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan; 2Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan; 3Institute of Biomedical Imaging and Radiological Sciences, Taipei, Taiwan; 4Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan

Tardive dyskinesia (TD), the most severe side effect of antipsychotics, is characterized by late-onset, repetitive involuntary choreiform movement, tics and grimaces of the orofacial muscles, and dyskinesia of the distal limbs. Pervious studies have suggested that schizophrenic patients with TD had an excess of neurodevelopmental disturbance, particularly minor physical anomalies, in association with cognitive dysfunction and abnormalities of cerebral structure. Abnormality of white matter (WM) change with schizophrenia had been found, but no report ever investigated WM abnormality of TD. Here we presented a study on schizophrenia subjects with/without TD and healthy subjects using voxel-based diffusion tensor imaging technique


MRI of Animal Brain

Hall D                                   Thursday 13:30-15:30                                                                                                                                           

Text Box:  
                  2305.     MRI Look Locker Estimates of the Longitudinal Relaxation Rate Are Approximately Linear in Contrast
         Agent  Tissue Concentration

Ramesh Paudyal1, 2, Hassan Bagher-Ebadian3, Tavarekere N. Nagaraja3, Swayam Panda3, Joseph D. Fenstermacher3, James R. Ewing, 13

1Oakland University, Rochester, Michigan, USA; 2Henry Ford  Hospital, Detroit, Michigan, USA; 3Henry Ford Hospital, Detroit, Michigan, USA

We investigate the effect of intra- to extracellular water exchange on a Look-Locker estimate of the tissue longitudinal relaxation rate, R1, when contrast agent (CA) enters the extracellular space.  We demonstrate through modeling and experiments in cerebral tumor that Look-Locker estimates of tissue R1 scale approximately linearly with tissue concentration of CA.

                  2306.     Opening the Blood Brain Barrier with Ultrasound for in Vivo Contrast-Enhanced Imaging of the
                                 Mouse Brain

Gabriel Philip Howles1, 2, Kristin Frinkley1, Yi Qi1, Kathryn Nightingale1, G A. Johnson1

1Duke University, Durham, North Carolina, USA

In vivo MRI of the mouse brain is limited by the long T1 of the brain.  T1-shortening contrast agents are excluded from the brain by the blood brain barrier (BBB).  We present here a novel technique for BBB Opening with Lipid microspheres and UltraSound (BOLUS).  The co-administration of perflutren lipid microspheres and ultrasound opens the BBB both globally and non-invasively.  Using this technique, Gd-DTPA can enter the brain, enabling contrast-enhanced imaging in vivo.  With contrast enhancement, high-resolution (50x50x100 µm3) T1-weighted brain images can be acquired in less than one hour.

                  2307.     Early Life Stress: Longitudinal Monitoring of Morphological Impact on the Hippocampus Using in Vivo
                                MR-Imaging in Mouse Model

Wilfried Reichardt1, Claus Gross2, Inga Herpfer2, Carola Haas2, Klaus Lieb2, Dominik von Elverfeldt1

1University of Freiburg, Freiburg, Germany; 2University Hospital Freiburg, Freiburg, Germany

Early life stress constitutes a risk factor for the development of psychological disorders, such as depression in human. Early life stress was modelled in C57Bl6 mice using a model of unpredictable maternal separation (daily 3h, between post-natal days 1-14). Previous results of our group had shown sex-related differences on RNA- and protein level between the experimental groups, especially at day 15 post partum. We set out to show, that it is possible to detect morphological changes of the hippocampus in an early life stress model in mice using highresolution in vivo MRI.

                  2308.     Hippocampal Anisotropy is Associated with Dendritic Quantity

Jason C. Pych1, 2, P N. Vankatasubramanian1, 3, James Faulkner IV1, Alice M. Wyrwicz1, 3

1ENH Research Institute, Evanston, Illinois, USA; 2Northwestern University Weinberg College of Arts and Sciences, Evanston, Illinois, USA; 3Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA

Previous research from our lab found that diffusion tensor imaging-derived fractional anisotropy (DTI-FA) values are lower in the hippocampus of Tg2576 Alzheimer’s Disease mice than in wildtype controls.  The present study seeks to understand the structural correlates of hippocampal anisotropy.  The hippocampi of mice were characterized via DTI-FA and microscopy at 3 or 5 months of age.  Results demonstrated that both FA and the percent of neuropil occupied by dendrites increased from 3 to 5 months of age, supporting the hypothesis that an increase in FA is associated with an increase in the number of dendrites in the hippocampus.

                  2309.     Magnetic Resonance Imaging of Acute Alterations in the Rat Brain Following Simulated Space Radiation

Lei Huang1, Anna Smith1, Peter Cummings2, Edward J. Kendall3, Andre Obenaus1

1Loma Linda University School of Medicine, Loma Linda, California , USA; 2University of Virginia, Charlottesville, Virginia , USA; 3Memorial University of Newfoundland, St. John's, Canada

In the rat model of space radiation, we reported here the sensitivity of quantitative MRI in assessment of acute molecular disturbances in brain. At 1 week after whole-brain only 56Fe radiation (0, 1, 2 and 4 Gy) with 6 rats per group, T2WI, DWI and CET1 were performed. In absence of visible abnormalities in the images, quantitative analysis T2WI and DWI revealed the significantly increase in T2 relaxation time and decrease of ADC within hippocampus and entorhinal cortex. Except for the variable astrocytes activation in 4 Gy group, neuropathology was not evident. This approach may be translatable to clinical context.

                  2310.     Investigating the Role of SuFu in Cerebellar Development

Matthijs Christiaan van Eede1, Jung-Eun Jinny Kim, Shoshana Spring1, Jason P. Lerch1, Norman Rosenblum2, R M. Henkelman1

1Toronto Centre for Phenogenomics, Toronto, Canada; 2The Hospital for Sick Children, Toronto, Canada

MRI techniques have been increasingly used for phenotyping mouse models. This study has provided proof of principle of the power of MR imaging in the Sufu mutants, resulting in striking visual malformations of the cerebellum.

                  2311.     Quantitative MRI to Study Ocular Drug Distribution from Sub-Tenons’ Injection

Susan S. Lee1, 2, David Z. D'Argenio1, Gevorg Karapetyan2, Ira Harutyunyan2, Hyun Kim2, Rex A. Moats2

1University of Southern California, Los Angeles, California , USA; 2Childrens Hospital Los Angeles, Los Angeles, California , USA

Drug distribution and pharmacokinetics of sub-Tenon's injection were studied with quantitative ocular MRI.  Depots of higher viscosity demonstrate longer residency time, and drug from the depot diffused from the sub-Tenon's space into the aqueous humor.  This study demonstrates that sub-Tenon's injection of viscous formulations have potential for sustained drug release.

                  2312.     Brain Redox Imaging Using Blood Brain Barrier Permeable Nitroxide MRI Contrast Agent

Fuminori Hyodo1, Kai-Hsiang Chuang, Artem G. Goloshevsky, Shingo Matsumoto1, James B. Mitchell1, Alan P. Koretsky, Murali C. Krishna1

1National Cancer Institute/NIH, Bethesda, USA

Reactive oxygen species (ROS) and compromised antioxidant defense may contribute to numerous brain disorders. Nitroxides are nontoxic stable organic free radicals having a single unpaired electron and therefore are capable of providing MRI contrast via shortening the longitudinal relaxation time (T1). In addition, nitroxides exhibit catalytic antioxidant activity. In this study, the ability of a blood brain barrier (BBB) permeable nitroxide, methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (MC-P), as an MRI contrast agent for brain tissue redox imaging was examined. Furthermore, MC-P relaxation in the rodent brain was quantified by MRI at 4.7 T using a fast Look-Locker (LL) T1 mapping sequence.


fMRI: Mechanisms

Hall D                                   Thursday 13:30-15:30                                                                                                                                           

                  2350.     Plausibility of Delayed Arteriolar Compliance as Cause of the BOLD Post-Stimulus Undershoot in
                                Presence of Post-Stimulus Elevation in CMRO2: The Arterial Balloon Model
 [Not Available]

Benedikt Andreas Poser1, 2, David Gordon Norris1, 2

1Radboud University, Nijmegen, Netherlands; 2University Duisburg-Essen, Essen, Germany

There is converging MR and optical imaging evidence suggesting the BOLD post-stimulus undershoot is caused by sustained oxygen metabolism, and that activation related CBV changes occur in the arterial/arteriolar compartment. Under the hypothesis that capillary/venous CBV and CBF rapidly and simultaneously return to base after the stimulus but CMRO2 remains elevated, a sharp transition into the undershoot would ensue. As this is typically not observed there must be a mechanism counteracting rapid accumulation of deoxyhemoglobin in the capillaries. We propose, and in simulations show plausible, that delayed arterial compliance (‘arterial ballooning’) can cause the observed temporal characteristics of the undershoot.

                  2351.     A Multicompartment Vascular Model for Multimodal Analysis

Theodore J. Huppert1, Solomon G. Diamond2, David A. Boas3

1University of Pttsburgh, Pittsburgh, Pennsylvania, USA; 2Dartmouth College, USA; 3Massachusetts General Hospital, USA

We describe a dynamic multi-compartment Windkessel model for combining multimodal flow, BOLD, and optical measurements.

                  2352.     Quantification of Vessel Contribution to BOLD Nonlinearity

Nanyin Zhang1, Xiao-Hong Zhu1, Wei Chen1

1University of Minnesota, Minneapolis, Minnesota, USA

We have demonstrated that the source of BOLD nonlinearity can completely originate from vascular origin. To further investigate which component(s) inside the vascular tree (capillary or venous vessel) has dominant contributions, we divided all activated pixels in ROI into two groups: in one group, all voxels primarily contain microvasculature; in the other group, voxels are biased by large vessels. By removing all the activated pixels located at large vessels, we found BOLD nonlinearity becomes much less significant. This observation suggests that a very large component, if not all, of BOLD refractoriness is attributed to large vessels.

                  2353.     Single-Subject Hemodynamic Refractory Effects in Healthy Volunteers

Benedicte Descamps1, Pieter Vandemaele1, Koen Paemeleire1, 2, Luc Leybaert2, Eric Achten1

1Ghent University Hospital, Ghent, Belgium; 2Ghent University, Ghent, Belgium

We propose a method to measure hemodynamic refractory effects in a single subject. With four different conditions and an acquisition time of 45’30”, reducible to 23’15”, non-linearity of the hemodynamic response could be demonstrated within a single subject. Several processing methods are compared. Very short interstimulus intervals tend to show larger differences then longer interstimulus intervals and one should take this into account when using fast event-related designs. Because migraineurs may lack these refractory effects, this measurement method could be used to distinguish them from healthy volunteers.

                  2354.     Stimulus Frequency Dependency of Postive BOLD (PBOLD) and  Post Stimulus Undershoot (PSU)

Uzay Emrah Emir1, Zubeyir Bayraktaroglu2, Ahmet Sabri Alper3, Ahmet Ademoglu3, Cengizhan Ozturk3, Tamer Demiralp2

1Bogazici University, Istanbul, Turkey; 2Istanbul University, Istanbul, Turkey; 3Bogazici University, Istanbul, Turkey

most of the researches on BOLD transients were studied with input stimulus frequencies up to 30Hz. An interesting question is how BOLD transient components including the PSU change their behavior when stimulated with a finer frequency resolution up to 40 Hz. In this study we focused on PBOLD and PSU responses during to the stimulation frequencies beyond 8Hz and explored the additional local maxima emerging from a stimulation scheme with a finer frequency resolution. The correlation between the PBOLD and PSU across different stimulation frequencies was analyzed to explore the underlying physiological mechanisms of these two transients.

                  2355.     Inflow Effects on Hemodynamic Responses Characterized by Gradient-Echo BOLD Functional MRI

Pei-Shan Wei1, Yau-Yau Wai1, 2, Wan-Chun Kuan3, Chih-Mao Huang1, 2, Changwei W. Wu4, Yung-Liang Wan1, 2, Ho-Ling Liu1, 2

1Chang Gung University, Taoyuan, Taiwan; 2Chang Gung Memorial Hospital, Taoyuan, Taiwan; 3National Tsing Hua University, Hsinchu, Taiwan; 4National Taiwan University, Taipei, Taiwan

Inflow effects on the measured BOLD hemodynamic responses (HRs) of visual stimulations were investigated using gradient echo EPI (TR = 1 s, FA = 300, 600 and 900) at 3 T and 1.5 T. Inflow related signal increases were observed only in the 3T results.  Comparing the HRs from the 3T results, the 900-FA responses exhibited latencies significantly faster than the 300-FA. The falling times of the 900-FA responses were later than those of the 300-FA, but the differences were not statistically significant. The 900-FA responses demonstrated greater latency variations than the 300-FA when comparing at the same CNR levels.

                  2356.     Spatial and Temporal Characteristics of the FMRI Response to Brief Somatosensory Stimulation in Rats

Yoshiyuki Hirano1, Bojana Stefanovic1, George C. Nascimento1, Afonso C. Silva1

1National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA

The BOLD, CBF and CBV hemodynamic response (HDR) to brief somatosensory stimulation was measured in rats. The HDR to a single 333 μ s pulse was easily detectable and it was confined to medially located regions in S1FL. These results suggest that the HDR to extremely brief stimuli will allow for a better understanding of the mechanisms of neurovascular coupling and allow establishment of the ultimately achievable spatial and temporal resolution of functional neuroimaging.

                  2357.     Effect of Acoustic Imaging Noise and Recent Acoustic History on Auditory FMRI Response

Olumide Olulade1, Shuowen Hu1, Greg Tamer, Jr. 1, Joseph Santos1, Wen-Ming Luh, Thomas Talavage1

1Purdue University, West Lafayette, Indiana, USA

A complicating factor in event-related auditory fMRI analysis is Acoustic Imaging Noise (AIN), produced by rapidly switching gradients during echo planar imaging. The presence of AIN alters fMRI detection of auditory stimuli by producing undesired neuronal activations that can mask stimulus-induced responses. Additionally, activation accumulated over multiple stimuli can elevate the baseline, reducing the available dynamic range. To best evaluate responses to auditory stimuli, there is a need to account for the presence of AIN, beginning with an understanding of the extent of memory in the system, herein referred to as the necessary duration of the acoustic time history of an experiment. A first step toward this goal is examination of the dependence of response attenuation on inter-stimulus interval (ISI) and repetition time (TR).

                  2358.     A Comparison of the BOLD Response Between Two High Magnetic Field Strengths: 7.0 and 11.7 Tesla

Joerg Ulrich Seehafer1, Andreas Beyrau1, Tracy Deanne Farr1, Pedro Ramos-Cabrer2, Dirk Wiedermann1, Mathias Hoehn1

1Max Planck Institute for Neurological Research, Cologne, Germany; 2Hospital Clínico Universitario de Santiago, Santiago de Compostela, Spain

Our objective was to compare the BOLD response following forepaw stimulation in rats in two horizontal small animal MRI systems: 7.0 Tesla and a new 11.7 Tesla system. Using the same MR-protocol on both systems we show that increased magnetic field strength and SNR do not lead to higher BOLD signal changes in S1 or S2 areas, but to a better detectability of activated pixels. Subsequently, we used a protocol optimized for the higher gradient strength at 11.7 Tesla, which resulted in high-resolution BOLD-EPI images that showed also activation in thalamus, as well as structure of cortical layers.

                  2359.     Correlation of CBV Changes with FMRI and Laser-Doppler Measurements: Implications on CMRO2

Peter Herman1, 2, Basavaraju Ganganna Sanganahalli1, Fahmeed Hyder1

1Yale University, New Haven, Connecticut, USA

Quantitative mapping of changes in CMRO2 with BOLD calibration require multi-modal MRI measurements of CBF, CBV, and BOLD. CBF measurements are frequently substituted by laser-Doppler measurements while the CBV measurement can be estimated by vascular physiology based models. We found an alternative method to estimate the CBV changes during stimulation using backscattered light intensity signals from the laser-Doppler measurement. We found a strong correlation between the fMRI measured CBV and the optically measured back scattered light intensity. The backscattered intensity signal follows the CBV changes, therefore it can substitute the CBV measurement without any modeling effort to calculate the CMRO2


fMRI: Multimodal Integration

Hall D                                   Thursday 13:30-15:30                                                                                                                                           

Text Box:  

                  2421.     Distances Between EEG Spikes, BOLD Activation and Lesions for Different EEG Techniques

Mario Forjaz Secca1, 2, Joana Cabral1, Henrique Fernandes1, Alberto Leal3

1Universidade Nova de Lisboa, Monte de Caparica, Portugal; 2Ressonancia Magnetica - Caselas, Lisboa, Portugal; 3Hospital Julio de Matos, Lisboa, Portugal

One of the common treatments in drug resistant Epilepsy is the surgical removal of the “offending” part of the brain and its success depends on the accurate localization of the focal region in the brain generating the seizures. The goal of EEG and MR Imaging is to help localization in presurgical evaluation, however the two techniques differ slightly and are not coincident with the lesion. So we quantified the distance between the EEG dipoles, the BOLD clusters and the lesions for different inverse problem approaches in order to develop analysis methods that diminish that discrepancy.

                  2422.     The Relationship Between the FMRI BOLD Response and Beta Band Neuromagnetic Effects

Claire Stevenson1, Matthew Brookes1, Peter Morris1

1The University of Nottingham, Nottingham, UK

There is a good correlation between fMRI BOLD data and induced oscillatory effects in MEG. Here, the induced oscillatory response in the beta-band is measured by MEG and the haemodynamic response is measured by fMRI for both finger movement of varying durations and visual stimuli of varying contrast. The linearity of the responses is assessed in order to determine the extent to which the BOLD response is governed by beta activity. The excellent co-localisation of BOLD and beta activity strongly suggests that the two processes are linked.

                  2423.     Assessment of BOLD Signal Adaptation Using Single Event FMRI at 7 T and Its Correlation with MEG

Peter J. Wright1, M Brookes1, J Dixon1, P Morris1, P Gowland1, S Francis1

1University of Nottingham, Nottingham, UK

Recent studies have shown the fMRI BOLD response becomes smaller over time, suggesting a degree of adaptation of the response. However the indirect nature of the BOLD response means that the cause of this adaptation is unclear.  In the present work we compare the degree of adaptation observed using both MEG and fMRI at 7 T. Results show that 7 T fMRI can be used to measure and fit the haemodynamic response on a trial by trial basis. We found adaptation in the fMRI response but not the MEG evoked response to median nerve stimulation in two subjects.

                  2424.     Is the Habituation of the Visual Evoked EEG Response Reflected in the Simultaneously Acquired BOLD
                                and ASL FMRI Signals?

Stephen Daniel Mayhew1, 2, Bradley John MacIntosh1, Sharon G. Dirckx1, Kyle T.S Pattinson1, Richard Geoffrey Wise2

1University of Oxford, Oxford, UK; 2University of Cardiff, Cardiff, UK

We investigated the neurovascular coupling in the human brain between the visual-evoked responses measured during simultaneous recording of EEG-BOLD and EEG-ASL. We correlated the temporal features of BOLD and CBF signals with EEG measurements of the underlying neural activity. A significant decrease in the amplitude of the visual-evoked EEG response was measured across a 30-s block of stimulation. No corresponding habituation was measured with BOLD fMRI, but a significant subtle habituation of the CBF response was measured using a region-of-interest based analysis. This suggests the neuronal EEG response may be better temporally correlated with CBF than with BOLD haemodynamic fMRI signals.

                  2425.     Validation of Calibrated MRI Using Continuous-Wave and Time-Domain Near-Infrared Spectroscopic

Claudine Gauthier1, 2, Louis Gagnon, 23, Juliette Selb4, David Boas4, Frédéric Lesage, 23, Richard D. Hoge1, 2

1Université de Montréal, Montreal, Canada; 2Institut de gériatrie de Montréal, Montreal, Canada; 3École Polytechnique de Montréal, Montreal, Canada; 4Massachusetts General Hospital, Charlestown, Massachusetts, USA

MRI-based estimates of task-induced changes in oxygen consumption were validated using near infrared spectroscopic imaging in both continuous-wave and time-domain modes.  This combination of optical measures allowed determination of the fractional change in tissue deoxyhemoglobin concentration, which was compared with values implied by the MRI model during hypercapnia and a motor task.  Fractional dHb changes during hypercapnia were in close agreement for the two methods.  Changes measured by optical imaging during the task were lower than those suggested by MRI, to a degree consistent with the partial volume effect in the optical data.

                  2426.     Simultaneous EEG-FMRI Acquisition: Effect of Choice of MRI Pulse Sequence on Gradient Artifacts
                                and EEG Data Quality

Hari M. Bharadwaj1, Scott Peltier1, Douglas C. Noll1, Jinsoo Chun1, Patricia J. Deldin1

1University of Michigan, Ann Arbor, USA

Multimodal functional neuroimaging with EEG and fMRI offers great promise for the future. With the advent of a wide variety of pulse sequences for fast and high resolution fMRI, it is necessary to understand the effect of the choice of pulse sequence on EEG data quality in multimodal experiments. A study was performed using two commonly used pulse sequences:EPI and Spiral. Both task activation and resting state conditions were studied. The gradient artifacts were removed independently using 2 different artifact removal algorithms. It was found that the EEG data acquired concurrently with EPI was more akin to the EEG data acquired during no MR acquisition. This is attributed to the fact that the EPI gradient waveforms are spectrally disjoint with the EEG bands on interest (0-70 Hz) and the Spiral gradients have significant overlap. 

                  2427.     Minimalist EEG-Recording for Improving FMRI: Simple Encoding of Noise Variables in MRI Data

Lars G. Hanson1, Arnold Skimminge1, Christian G. Hanson1

1Copenhagen University Hospital, Hvidovre, Denmark

Most fMRI studies can benefit from simultaneous recording of EEG and other electrophysiological signals, even when EEG is not of interest in itself. It is demonstrated that simple hardware and few, easily positioned electrodes can provide measures of eye-blinks, alpha-activity and pulse that increases fMRI sensitivity and reliability. The analysis is facilitated by EEG and MRI being measured and stored together by the scanner.

                  2428.     A New Hardware-Software Coil Positioning System for Interleaved TMS/fMRI: A Motor Cortex Stimulation

Marius Moisa1, Kamil Uludag1, Kamil Ugurbil1, Axel Thielscher1

1Max Planck Institute for Biological Cybernetics, Tübingen, Germany

Interleaved TMS/fMRI is a promising technique to study connectivity between brain areas. An important practical challenge is the positioning of the coil inside the MRI scanner. We describe a novel method that combines software and hardware for accurate TMS coil placement and report pilot results on its usage studying the motor system. In a phantom study, the accuracy of the method was demonstrated to be within the range previously reported for normal neuronavigation systems. The results of the motor cortex study are in concordance with prior findings, demonstrating the viability of our positioning method and our overall interleaved TMS/fMRI setup.

                  2429.     Improved Artifact Rejection for Simultaneous EEG/fMRI at 7T Using a High EEG Channel Density
                                and a Vector Beamformer

Matthew Jon Brookes1, Karen Julia Mullinger1, Gerda Bjork Geirsdottir1, Claire Michelle Stevenson1, Peter Gordon Morris1, Richard William Bowtell1

1University of Nottingham, Nottingham, UK

Previously it has been shown that the application of a vector beamformer to EEG data recorded simultaneously with fMRI allows for source localization of electrical responses, extraction of the timecourse of neuronal activity and rejection of residual artifacts induced in the EEG data by the MR scanner. In this work we show that the signal to noise ratio of beamformer-reconstructed estimates of electrical activity is improved by the use of increased numbers of EEG channels. Furthermore, we show that the beamformer approach allows for the measurement of low amplitude, high frequency gamma band electrical effects at ultra high field (7T).

                  2430.     Electrical and Haemodynamic Effects Measured Using MEG and Combined EEG/fMRI

Matthew Jon Brookes1, Karen Julia Mullinger1, Claire Michelle Stevenson1, Gerda Bjork Geirsdottir1, Richard William Bowtell1, Peter Gordon Morris1

1University of Nottingham, Nottingham, UK

Recent MEG studies have shown that evoked (1-40Hz) and gamma band (50-200Hz) neuronal responses can be measured in the 100ms time window immediately following electrical stimulation of the median nerve. Here we measure these characteristic responses using both MEG and EEG recorded simultaneously with 7T fMRI. We show that a combination of averaged artifact subtraction and an EEG beamformer allows for adequate SNR to record low amplitude gamma band effects in EEG/fMRI. Furthermore, we show that the EEG and MEG signals are temporally comparable to each other, and spatially coincident with the haemodynamic response.

                  2431.     An Approach for Fusion Between EEG and FMRI Data

Lei Wu1, 2, Vince Daniel Calhoun1, 2

1The Mind Research Network, Albuquerque, New Mexico, USA; 2University of New Mexico, Albuquerque, New Mexico, USA

An improved ICA to fuse multi-channel ERP and fMRI with high spatialtemporal resolutions in AOD tasks was presented. We acquired and preprocessed the data first, then used PCA data reduction, pseudo reconstruction, jICA capturing relationships between different modalities and hybrid data simulation. For all sub-methods, the components can be separated well. Different peaks of ERP match different regions of activities of fMRI. The ERP components from multi-channels correspond better to sources than those from single channels. Dipolar close to cz channel works better than other locations. Therefore, we can reveal the EEG-fMRI signals’ relationship and enhance the visualization of neural responses. 

                  2432.     Near-IR Optical Calibration of the BOLD Signal

Theodore J. Huppert1, Solomon G. Diamond2, David A. Boas3

1University of Pttsburgh, Pittsburgh, Pennsylvania, USA; 2Dartmouth College, USA; 3Massachusetts General Hospital, USA

In this work, we use concurrently measured near-IR optical measurements to calibrate the BOLD signal.  We develop a data fusion model to incorporate both optical and BOLD measurements into a unified model of the underlying hemodynamic response.  Through simulations and experimental results, we demonstrate the improved quantitative accuracy of our model.

                  2433.     Current Density Weighted Indices for Correspondence Between FMRI with Electrocortical Stimulation

Desmond Teck Beng Yeo1, 2, Charles R. Meyer2, Jack M. Parent2, Daniela N. Minecan2, Oren Sagher2, Karen J. Kluin2, Boklye Kim2

1University of Michigan, Ann Arbor, Michigan, USA; 2University of Michigan Medical School, Ann Arbor, Michigan, USA

The gold standard for presurgical brain mapping is subdural electrocortical stimulation (ECS), which is an invasive procedure. Functional MRI (fMRI), a non-invasive technique, may be a plausible alternative. However, it must be shown that fMRI-ECS activation maps are spatially consistent. There are indications that the level of elicited neuronal activation is influenced by electrical stimulus levels, and thus, a correspondence index that incorporates current density information may be physically more meaningful. This work formulates a 3D current density weighted method to measure ECS-fMRI correspondence for our clinical ECS-fMRI mapping procedure. Euclidean distance information between activated voxels and ON/ OFF electrode pairs is embedded in current density maps obtained by solving the Laplace equation for a quasistatic volume conductor. The proposed current density weighted indices were computed for three patient datasets.


fMRI Analysis Methods

Hall D                                   Thursday 13:30-15:30                                                                                                                                           

                  2478.     Using Local Field Potential Information Instead of the Block Design Model for BOLD Analysis  [Not Available]

Joanna K. Huttunen1, Lauri Lehto1, Antti M. Airaksinen1, Markku Penttonen2, Olli Gröhn1

1University of Kuopio, Kuopio, Finland; 2University of Jyväskylä, Jyväskylä, Finland

Simultaneous local field potential and functional magnetic resonance imaging measurements provide unique premise to use the information measured directly from the brain as the model of the BOLD signal in fMRI analysis. Conventionally the block design model has been used in BOLD analysis. In this study we made the model by using the simultaneously measured LFP signal. In most cases, the LFP model predicts the activation in the somatosensory cortex of a rat similarly to the block design model, but the LFP model predicts the activation in all cases when no activation was detected with the block design model.

                  2479.     MDL-Based Estimation of the Hemodynamic Response Function for FMRI Data

Negar Bazargani1, Aria Nosratinia1

1University of Texas at Dallas, Richardson, USA

We propose a method based on the minimum description length (MDL) principle to estimate the hemodynamic response function (HRF) from fMRI data. The proposed method provides a nonparametric approach to HRF estimation without any explicit assumptions. The simulation results show the ability of the MDL-based algorithm to estimate the benchmark HRF with good precision. The statistical analysis with the estimated HRF shows better estimates of the t-statistics compared with that from fixed HRF models. Also, the HRF variability can be captured by this method.

                  2480.     Comparison of Linear Parametric Models for Predicting fMRI Response

Parina J. Gandhi1, Bharat B. Biswal1

1UMDNJ, Newark, New Jersey, USA

The purpose of this study was to compare different parametric models and in particular their ability to predict the fMRI response. The transfer function for each voxel depends upon the complex interactions among neurons, underlying hemodynamic function and the task. However, the linear transform model may vary on a voxel by voxel basis. The noise also plays an important role in predicting the stimulated response. This helps in understanding the underlying neuronal activity of the brain. Investigators have tried to predict the fMRI response using linear-time invariant (LTI) techniques. In a LTI system, an output can be determined by convolving the input with the transfer function. Boynton and colleagues [1] characterized LTI relationship between fMRI and neural activity. In a similar study, Glover [2] measured the temporal characteristics of the BOLD response in sensorimotor and auditory cortices while stimuli were presented that varied between durations of 167 msec to 16 seconds. Cohen [3] used a gamma-variate model to fit the impulse response function with the behavioral conditions to obtain a better prediction of the fMRI response.

                  2481.     Sparse Decoding in FMRI

Jongho Lee1, Masaki Fukunaga1, Marta Bianciardi1, Jacco de Zwart1, Peter van Gelderen1, Jeff H. Duyn1

1National Institute of Health, Bethesda, Maryland, USA

Under the assumption of sparsity, fMRI data are decomposed into several sources. The resulting sources show good correspondences with the task pattern and the resting-state maps.

                  2482.     A Multivariate Approach to FMRI-Based Subject Discrimination

Jeff John Fortuna1, 2, Michael D. Noseworthy1, 2, Adrian Matthew Yuri Koziak2, John MacGregor1

1McMaster University, Hamilton, Canada; 2Brain-Body Institute, Hamilton, Canada

A novel multivariate approach to between-subject fMRI analysis based on multi-way linear algebra and PCA is presented. The approach was compared to a traditional linear regression analysis applied to an experiment which attempted to discriminate between male and female responses to images of human faces. The three spatial, one temporal and one subject dimensions of the fMRI data was collapsed into a two-dimensional data matrix (each row was a spatiotemporal representation of each subject). PCA was used to provide a two-dimensional representation of each subject. In this space, male and female subjects were grouped sufficiently to be linearly separable.

                  2483.     Detecting Outliers in FMRI Studies with Small Sample Size

Rutuparna Sarangi1, Samata M. Kakkad1, Bharat B. Biswal, 1

1UMDNJ, Newark, New Jersey, USA

The purpose of this study was to develop a method to detect outliers for smaller subject populations. In most of the fMRI experiments conducted, one assumes that the variations among subjects are minimal and that the resulting errors are random and Gaussian in nature.  However, the data sets used in fMRI are small (usually less than 20 subjects) and cannot be easily determined as fitting the Gaussian model. Besides, increasing the risk of errors in the measurement of the distribution parameters, there is a possibility that the distribution which is being modeled is not the correct distribution. In the case of an outlier, there is no immediate way to differentiate between outliers and normal data points. The outliers can either increase or decrease the “mean” averages.  To compensate for this, the subject population usually associated with the fMRI experiments (15-20 subjects) can be increased (80 or more subjects) to make it easier to detect outliers and give a more accurate resampling data sets. In addition to being expensive due to increased scanning time, and other subject related costs, for certain patient populations, it is not possible to increase the sample size to 80 or 100. In this paper, we present a method for detecting outliers in small sample sizes.

                  2484.     An Improved Algorithm for Data Reduction Prior to Independent Component Analysis of Functional
                                MRI Data in the Presence of Colored Noise and Low Source Signal-To-Noise Ratio

Vincent Jerome Schmithorst1, Scott Kerry Holland1

1Children's Hospital Medical Center, Cincinnati, Ohio, USA

Data reduction (usually performed via Principal Component Analysis, PCA) and accurate model order estimation are necessary for accurate blind-source-separation in noisy data, performed via a method such as Independent Component Analysis (ICA).  PCA assumes white noise while noise in fMRI data can have significant temporal autocorrelation.  A data reduction method has been previously published which uses an AR(1) model of the noise.  However, the method significantly underestimates the model order at low SNR.  We modify the technique for accurate estimation of the model order and extraction of the source subspace in the presence of colored noise and low source SNR.

                  2485.     Identification of Brain Image Biomarkers by Optimized Selection of Multimodal Independent Components

Rogers Ferreira da Silva1, 2, Vince Daniel Calhoun, 12

1University of New Mexico, Albuquerque, New Mexico, USA; 2The MIND Research Network, Albuquerque, New Mexico, USA

This study is a segment of a broad research on the analysis of multimodal datasets for the investigation of mental illness and brain diseases. It is dedicated to the use of a data fusion analysis method popular in the neuroscience community called joint independent component analysis (jICA) which has been shown to be able to reveal hidden ‘cross’-information lying within heterogeneous datasets. Our specific goal is the use of an optimization factor based on the distributions of the independent components obtained from jICA to select the (set of) component(s) that mostly discriminates groups of individuals.

                  2486.     Classification of ICA FMRI Data Using Suppot Vector Machines

Xuelin Cui1, Michael Cole2, Linda Chang3, Thomas Ernst3, Benjamin Stokes3, Victor Andrew Stenger3

1Univeristy of Hawaii, Manoa, Honolulu, Hawaii, USA; 2John A. Burns School of Medicine, University of Hawaii, Manoa, Honolulu, Hawaii, USA; 3John A. Burns School of Medicine, Univeristy of Hawaii.Manoa, Honolulu, Hawaii, USA

Independent component analysis (ICA) of fMRI data is of current interest because it is data driven [1], requiring no a priori activation model. Unfortunately, visual inspection is still the most common way of determining meaningful IC¡¯s. Several techniques have been proposed to automatically classify IC¡¯s in fMRI [2]. In this work a technique based on 3D discrete wavelet transform (3DDWT) compression and support vector machine (SVM) classifiers is presented. We found that this approach could successfully classify IC¡¯s in a block-designed fMRI experiment at 3T.

                  2487.     Fuzzy Clustering on FMRI Responses Using Autocorrelation Function Features

Cheng-Chieh Cheng1, Fu-Nien Wang2, Hsiao-Wen Chung1

1National Taiwan University, Taipei, Taiwan; 2National Tsing Hua University, Hsinchu, Taiwan

In fMRI analysis, data-driven methods are taken to generate the activation patterns, while dimension reduction strategies must be applied to overcome the high computational complexity. Autocorrelation function (ACF) is commonly used to exclude possibly inactive voxels, however, features of the ACF contain important information of signal as well as noise. Thus, we proposed to use the features in the ACF domain not only to differentiate signal and noise, but also to summarize different signal sources. After applying fuzzy C-means algorithm for clustering, averaged time courses (ATCs) are generated to be our activation patterns. In our study, very high correlation (>0.8) between the original data and ATCs is represented.

                  2488.     Bayesian Variable Selection in FMRI

Bradley McEvoy1, Rajesh Nandy1

1UCLA, Los Angeles, California , USA

The classical analysis of fMRI data is characterized by a two step process-a statistical model and a thresholding process. This paradigm, though informative, performs these steps as independent processes. In other words, the statistical model is run independent of the thresholding process. We propose to unite these steps under one coherent framework. We achieve this by exploiting characteristics of the Bayesian variable selection technique Stochastic Search Variable Selection (SSVS). The appeal of this framework is it permits the inclusion of prior information on hypothesized effect and avoids sensitivity and specificity issues introduced by the thresholding.

                  2489.     Detection of Spinal Activation of Rat Using Generalized Likelihood Ratio Tests

Qiong Zhang1, Cheryl McCreary, Dave Kirk, Foniok Tadeusz, MIchael Smith1, Jeff Dunn

1University of Calgary, Calgary, Canada

To improve the detection of activation in spinal fMRI, the generalized likelihood ratio tests (GLRT) method based on the general linear model (GLM) was applied in this study. The GLRT method with a modified hemodynamic response function was applied to magnitude spinal fMRI data on Gaussian distribution and Rician distribution respectively.The results show that the GLRT method with HRF could detect the activation regions with higher detection rate than Student-t test in the Gaussian case.

                  2490.     Modeling of Phase Changes in BOLD FMR

Zhaomei Feng1, 2, Arvind Caprihan1, Kraston Blagoev, Fuqiang Zhao, Vince D. Calhoun1, 2

1The MIND Institute, Albuquerque, New Mexico, USA; 2University of New Mexico, Albuquerque, New Mexico, USA

In order to better elucidate the source of the phase changes of BOLD fMRI in humans, simulations based on the theory of the Lorentz sphere are performed to model effects of volume-averaged magnetization and demagnetization. The phase model is applied to gradient-echo BOLD fMRI data collected from 16 human subjects during finger tapping experiments at 3 Tesla and preprocessed using the SPM5. The modeled phase change matches the experimentally observed phase change pattern. The agreement is true for all of the subjects studied. Further studies which include the effects of diffusion and large vessels are needed to refine the model.

                  2491.     Separating BOLD Activation from Stimulus-Correlated Motion by Means of Linear Source Extraction
                                Applied to Multi-Echo Data

Pieter François Buur1, Christian Wolfgang Hesse1, David Gordon Norris1

1F.C. Donders Centre for Cognitive Neuroimaging, Nijmegen, Netherlands

A novel method is presented that seeks to separate the R2* and S0 signal components in multi-echo fMRI data. The method makes no explicit assumptions about activation time-course or location and is based on a simple linear mixing model of how the sources R2* and S0 project onto the measured data. Using a paradigm where functional activation and subject motion occur simultaneously, succesful extraction of the two sources is achieved. As in principle, all physical processes that give rise to changes in S0 can be separated from those in R2*, the approach also holds promise to reduce e.g. physiological fluctuations.


fMRI Applications

Hall D                                   Thursday 13:30-15:30                                                                                                                                           

                  2517.     A High Resolution FMRI Study of Episodic Memory Retrieval at 7T

Bing Yao1, Tie-Qiang Li1, James K. Kroger2, Peter van Gelderen1, Jacco de Zwart1, Doerte Spring2, Jeff H. Duyn1

1National Institues of Health, Bethesda, Maryland, USA; 2New Mexico State University, Las Cruces, New Mexico, USA

The process of human memory retrieval was investigated in an event-related fMRI study using a 7T MR scanner. The results provide convinced evidences that both the medial and lateral anterior prefrontal cortex play important role in the memory retrieval process.

                  2518.     Using High-Resolution FMRI to Identify Individual-Specific Speech Motor Regions

Satrajit Sujit Ghosh1, Michael Hamm2, Karsten Jahns3, Christina Triantafyllou1, 4

1Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; 2Siemens Medical Solutions, Charlestown, Massachusetts, USA; 3Siemens Medical Solutions, Erlangen, Germany; 4Massachusetts General Hospital, Charlestown, Massachusetts, USA

The experiment aimed to dissociate speech related clusters of activity around ventral pre-motor cortex and the supplementary motor area in individuals. These clusters are difficult to separate using low-resolution scans. We utilized multi-channel phased-array coils to achieve high-resolution fMRI acquisition with 1mm and 2mm isotropic voxel sizes. Using data from a 32-channel coil, our findings demonstrate localization of sulcal bank-specific activity. Compared to a 12-channel head coil, the 32-channel coil provides greater sensitivity and precision to the size and location of brain activity. High-resolution data permits use of small smoothing kernels thus limiting smearing of activity across functionally distinct regions.

                  2519.     Functional Magnetic Resonance Imaging of the Motor Network with 65ms Time Resolution

Zoltan Nagy1, Chloe Hutton1, Ralf Deichmann1, 2, Nikolaus Weiskopf1

1University College London, London, UK; 2University of Frankfurt, Frankfurt, Germany

:  Functional magnetic resonance imaging (fMRI) is a widely used technique to image brain function. Its limitations include a relatively low time resolution (compared to EEG for example) and that the observed signal changes are related to hemodynamic response to neuronal activity and this response have regional and intersubject variability. We used a data re-ordering technique on an event-related data set to achieve a time series with 65ms time resolution. Based on this dataset we show demonstrate the regional variability of the hemodynamc response. In addition we also observed, region-specific, high-frequency changes in the signal.

                  2520.     Corticothalamic Neuronal Interaction Revealed by Dynamic FMRI

Nanyin Zhang1, Xiao-Hong Zhu1, Yi Zhang1, Wei Chen1

1University of Minnesota, Minneapolis, Minnesota, USA

It has recently been suggested that the LGN relay function is not as effective if it is in the ‘burst mode’, compared to the situation when it is in the ‘tonic mode’. In this study, we investigated the corticothalamic interaction using the dynamic fMRI approach. Both V1 and LGN activities are significantly suppressed when the visual system is within the refractory period. However, there is additional reduction in LGN BOLD activity compared to V1. This reduction is presumably induced by corticothalamic feedback. These results suggest that it is feasible to use the dynamic fMRI approach to investigate large-scale neural networks.

                  2521.     Spinal Cord Functional MRI: Gradient Echo Versus Spin Echo

Chris J.C. Bouwman1, 2, Walter H. Backes2

1Eindhoven University of Technology, Eindhoven, Netherlands; 2Maastricht University Hospital, Maastricht, Netherlands

Spin echo and gradient echo pulse sequences for cervical spinal cord fMRI were optimized for signal sensitivity and signal-to-noise characteristics and evaluated for finger motion tasks at 3T field strength. Gradient echo based fMRI appeared more signal sensitive, location-specific and reproducible than spin echo imaging.

                  2522.     Mapping Human Somatosensory Cortex with FMRI at 1 Mm Isotropic Resolution

Rosa Maria Sanchez Panchuelo1, Denis Schluppeck1, Sue Francis1, Richard Bowtell1

1University of Nottingham, Nottingham, UK

The increased BOLD contrast to noise ratio available at 7T has been exploited in measuring the topographic representation of the digits of the hand in human somatosensory cortex at 1 mm isotropic resolution in experimental runs of a less than 10 minutes duration. A ‘travelling wave’ paradigm was used and the data analysed using a Fourier-based method, normally employed in retinotopic mapping. Results were displayed on high resolution anatomical images and the inflated somatosensory cortex. Activation was confined to the grey matter strip and clearly showed the expected digit ordering along the postcentral gyrus.

                  2523.     Regularized Localized Parallel EVI: Application to the Study of Habituation Effects in FMRI  [Not Available]

Cécile Rabrait1, Philippe Ciuciu1, Alejandro Ribés1, Cyril Poupon1, Ghislaine Dehaene-Lambertz1, 2, Patrick Le Roux3, Denis Le Bihan1, Franck Lethimonnier1

1Commissariat à l'Energie Atomique, Gif-sur-Yvette, France; 2INSERM, Gif-sur-Yvette, France; 3GEHC, Buc, France

2D SENSE imaging and field-of-view reduction make Localized Parallel EVI a powerful 3D single-shot acquisition method, which allows the acquisition of relatively large brain volumes at high scanning rates. In this study, temporal SNR was increased due to the optimization of the acquisition parameters and the regularization of parallel reconstruction. The efficiency of the optimized setting has then been demonstrated using a language comprehension task inducing habituation effects.  High temporal resolution single-voxel hemodynamic response function have been estimated and their timing properties have been extracted. This new approach could improve the understanding of complex neurovascular mechanisms.

                  2524.     Interaction Between GCBF and RCBF and Normalization of Language BOLD FMR Maps Using Breath

Gianpaolo Basso1, Stefano Magon2, Jens Volkmar Schwarzbach1, Manuela Orsini1, Nico Dario Papinutto1

1University of Trento, Mattarello, Tennessee, Italy; 2University of Verona, Verona, Italy

Use of BOLD fMR to explore brain correlates of cognitive functions in humans must face possible confounding due to non-neural BOLD signal modifications. Notably, BOLD signal due to systemic CO2 modulation systemic of global cerebral blood flow (gCBF) could confound interpretations of BOLD signal related to regional cerebral blood flow (rCBF) due to neurovascular coupling. In the present study we found that gCBF modulation due to breath hold and rCBF due to a language task act additively in frontal and temporo-parietal language related areas. On the other hand, vascular reactivity maps obtained with breath hold allowed normalization of spatial variability of cognitive related BOLD maps.



Hall D                                   Thursday 13:30-15:30                                                                                                                                           

                  2565.     Localized  31P Saturation Transfer Reveals Differences in Gastrocnemius and Soleus Rates of ATP
                                Synthesis In-Vivo

Douglas E. Befroy1, Kitt Falk Petersen1, Gerald I. Shulman1, 2, Douglas L. Rothman1

1Yale University School of Medicine, New Haven, Connecticut, USA; 2Howard Hughes Medical Institute, New Haven, Connecticut, USA

Distinct muscle groups exhibit differences in function and metabolic activity and also differ in their response to the effects of aging and potentially disease. Due to signal/noise limitations, most MR studies of metabolic reaction rates in-vivo tend to examine regions comprising multiple muscle types. We demonstrate that muscle-specific rates of ATP synthesis can be measured at 4T using adiabatic ISIS-localized 31P saturation-transfer MRS, and that there are significant differences in the basal rates of ATP synthesis between the soleus and gastrocnemius muscle groups in healthy subjects.

                  2566.     Comparative Analysis of Calf Muscle Metabolism in Children and Adults: A 31P MRS Study

Stefania Linsalata1, Amelia Mauro1, Roberta Battini1, Otello Presciutti2, Giovanni Cioni1, 3, Michela Tosetti1

1Stella Maris Scientific Institute, Pisa, Italy; 2University General Hospital, Perugia, Italy; 3University of Pisa, Pisa, Italy

We compared 31P MRS data obtained in the calf muscle of 4 children and 8 adults at rest, at the end of a short-term incremental exercise and during recovery.  Our results in children show a significant reduction of the PCr consumption at the end of the exercise combined with a significant higher pH, possible expression of the great resistance to fatigue in children. Moreover a slightly reduction of both the time constant t and the initial rate V of the PCr mono-exponential recovery confirms the hypothesis of a greater oxidative activity in children.

                  2567.     In-Magnet Bicycling Exercise: A Novel 31P MRS Window on the Energetics of Human Locomotion

Jeroen A.L. Jeneson1, Joep P.J. Schmitz1, Klaas Nicolay1

1Eindhoven University of Technology, Eindhoven, Netherlands

We have developed and implemented hardware on a clinical 1.5T MR scanner for innovative in-magnet bicycling exercise testing of human subjects. Three features of the first study reported here are of particular interest to (clinical) investigation of human exercise performance. Firstly, ATP metabolism in quadriceps muscle was studied over a 100-fold dynamic range with little intramuscular acidification. Secondly, the cardiovascular and pulmonary systems were significantly challenged during the exercise, with heart rates going up as high as 150 bpm. Finally, it provides a 31P MRS window on glycogen metabolism through the dynamics of hexose monophosphate resonances during exercise and recovery.

                  2568.     Quantification of Fatty Septa in Skeletal Muscle of the Lower Leg by T1-Weighted MRI and Correlation
                                to Anthropometric and Metabolic Data

Jürgen Machann1, Michael Bottcher1, Fabian Springer1, Norbert Stefan2, Hans-Ulrich Haring2, Claus D. Claussen3, Andreas Fritsche2, Fritz Schick1

1Section on Experimental Radiology, Tübingen, Germany; 2Department of Endocrinology, Metabolism, Clinical Chemistry, Nephrology and Angiology, Tübingen, Germany; 3Department of Diagnostic Radiology, Tübingen, Germany

Intramyocellular lipids (IMCL) are involved in the pathogenesis of insulin resistance. Up to now, there is no information, whether also intermuscular fat (IMF), i.e. the fat around the muscle fiber bundles, might be of importance. Aim of the study was the quantification of IMF, subcutaneous fat (SCAT) and muscle mass by T1-weighted MRI in volunteers at increased risk for type 2 diabetes and to correlate the results with anthropometric and metabolic data. In 249 subjects it could be shown that males have higher IMF but lower SCAT compared to females and that IMF is negatively correlated with insulin sensitivity.

                  2569.     Non-Negative Least Squares (NNLS) and Gated CSI Analyses of Phosphocreatine Recovery Kinetics in
                               Human Skeletal Muscle

Sean C. Forbes1, Anthony T. Paganini1, Jill M. Slade1, Theodore F. Towse1, Ronald A. Meyer1

1Michigan State University, East Lansing, USA

Phosphocreatine (PCr) recovery in human triceps surae muscle after low intensity exercise is mono-exponential, with the same recovery time constant in soleus, lateral, and medial gastrocnemius.  In contrast, after intense exercise an additional, fast component of PCr recovery occurs which can be attributed to anaerobic glycogenolysis. Thus, contrary to previous studies, PCr recovery after intense exercise is not entirely dependent on oxidative metabolism.

                  2570.     Identification of Distinct Patterns of Fat Metabolism in Skeletal Muscle of Male and Female Human
                               Subjects Using Localized 2-Dimensional Correlated Spectroscopy

Nicholas Said1, Kartik Narasimhan1, Cyrus Papan2, Richard G. Spencer3, Raymond R. Raylman1, Michael Albert Thomas4, Vazhaikkurichi M. Rajendran1, Stephen E. Alway1, S. Sendhil Velan1

1West Virginia University, Morgantown, USA; 2Institute of Bioengineering and Nanotechnology, Singapore; 3NIH/National Institute on Aging, Baltimore, USA; 4University of California, Los Angeles, Los Angeles, USA

Fatty acid metabolism plays a central role in the development of disorders of glucose metabolism, such as insulin resistance and diabetes, leading to significant interest in the detection of intramyocellular (IMCL) and extramyocellular (EMCL) pools in skeletal muscle.  In this study we have established gender differences skeletal muscle lipids in a group of male and female human subjects, consistent with the notion that endocrine status plays a critical role in fat metabolism. The influence of harmonal factors was further underscored by observed changes during menstrual cycle.

                  2571.     Rapid 13C Tip Angle / Coil Loading Calibration for in Vivo Natural Abundance 13C Studies in Humans

Peter Edward Thelwall1

1Newcastle University, Newcastle upon Tyne, UK

Surface coils are frequently employed for quantitative human in vivo 13C spectroscopy studies. Differences in volunteer morphology, such as subcutaneous fat layer thickness, can result in different coil loading between volunteers. Thus non-optimal tip angles may result in some scans, with power requirement differences of >40% observed for our subjects.Tip angle calibration is hindered by low natural abundance 13C signal, so we have employed a protocol for rapid calibration of 13C coil power requirements that employs a external marker with a short-T1 13C resonance. Optimal data acquisition aided accurate estimation of muscle glycogen content by natural abundance 13C spectroscopy.

                  2572.     Acute Effects of Rimonabant, a CB1 Receptor Antagonist, on IMCL and Plasma Parameters in Fed
                                Wistar Rats – a 1H-MRS Study

Claudia Neumann-Haefelin1, Johanna Kuhlmann1, Hans-Paul Juretschke1, Andreas W. Herling1

1Sanofi-Aventis, Frankfurt, Germany

Physiological and pharmacological studies for monitoring energy homeostasis focus predominantly on food intake, body weight and body composition, because these parameters are easily measurable in biomedical research. In acute preclinical studies cannabinoid CB1 receptor antagonists demonstrated an important reduction of food consumption and body weight. Until now rimonabant is the best characterized CB1 receptor antagonist and has been unequivocally proven to be pharmacological active in humans to reduce body weight and to improve metabolic parameters. The present study focus on the investigation of the acute pharmacological activity of rimonabant on metabolic plasma parameters and IMCL in fed Wistar rats.

                  2573.     Effect of High and Low Glycemic Index Recovery Diets on Skeletal Muscle Glycogen and Lipid Storage and

Peter Edward Thelwall1, Emma Stevenson2, Kevin Thomas2, Michael Trenell1

1Newcastle University, Newcastle upon Tyne, UK; 2Northumbria University, Newcastle upon Tyne, UK

High levels of carbohydrate intake have been shown to improve glycogen repletion after exercise. We tested whether the glycemic index of carbohydrate consumed post-exercise influences the storage and utilisation of skeletal muscle glycogen and/or lipid during subsequent exercise. Endurance-trained cyclists performed two 90 minute cycles at 70% VO2 peak, separated by a 24 hour recovery period. Between exercise the subjects ate either low or high glycemic index diets. Muscle glycogen and intracellular triglyceride content was measured with 13C and 1H MR spectroscopy. No significant differences in glycogen or triglyceride storage or utilisation were observed between the two diet groups.

                  2574.     Measurements of Taurine Distribution in Human Calf Muscle by 1H 2D-CSI at 7 Tesla

Jimin Ren1, 2, Ivan Dimitrov1, 3, A. Dean Sherry1, 4, Craig Malloy1, 5

1University of Texas Southwestern Medical Center, Dallas, USA; 2University of Texas Southwestern Medical Cente, Dallas, USA; 3Philips Medical Systems, Cleveland, USA; 4University of Texas at Dallas, Richardson, USA; 5VA North Texas Health Care System, Dallas, USA

Taurine, the most abundant free amino acid in most mammalian tissues, plays a role in numerous physiological processes. A taurine deficiency in mice is associated with loss of skeletal muscle function and total exercise capacity. We examined taurine distribution in human calf muscle by using 1H 2D-CSI at 7T. The results show heterogeneous distribution of taurine in human calf muscle, with high level of taurine (~15-25 mM) found in soleus and gastrocnemius, but below detection limits in flexor hallicus and tibialis posterior, in contrast to the levels of creatine and trimethylamino resonances in these same muscles.

                  2575.     Issues with Creatine/Phosphocreatine Quantification: Lipids Contamination and Water-Suppression

Jimin Ren1, 2, Ivan Dimitrov1, 2, James Murdoch2, A. Dean Sherry1, 3, Craig Malloy1, 4

1University of Texas Southwestern Medical Center, Dallas, USA; 2Philips Medical Systems, Cleveland, USA; 3University of Texas at Dallas, Richardson, USA; 4VA North Texas Health Care System, Dallas, USA

Creatine/phosphocreatine (Cr/PCr) quantification by 1H MRS is of particular interest due to the importance of Cr/PCr in energy metabolism, and the reference role of CH3-Cr/PCr resonance at 3.05ppm in standardizing other metabolites.   As shown in this study, however, the presence of large quantity of lipids in skeletal muscle may cause problems on CH3-Cr/PCr quantification, due to spectral overlapping between lipid and CH3-Cr/PCr.  Furthermore, the lack of spectral resolution between lipids and CH3-Cr/PCr may have caused confusion when water-suppression is applied, since it is the lipid signal at 3ppm, rather than that of CH3-Cr/PCr, attenuates upon water suppression, as we demonstrated.

                  2576.     High Resolution ASL and BOLD Imaging in Skeletal Muscle Using Spiral Sequences

Hao Tan1, Justin Anderson1, Hanna Woldeyesus1, Christopher M. Kramer1, Craig H. Meyer1

1University of Virginia, Charlottesville, Virginia , USA

Interest has recently renewed in functional magnetic resonance imaging (fMRI) in skeletal muscle. Similarly to fMRI in brain imaging, the blood oxygenation level-dependent (BOLD) effect has been used to study peripheral artery disease (PAD). In this study, we developed a new spiral sequence with four gradient echoes to estimate T2* maps. This sequence is combined with the Flow-Sensitive Alternating Inversion Recovery (FAIR) pulsed arterial spin labeling (ASL) sequence to measure perfusion and T2* near simultaneously. The combined ASL and BOLD measurements before and after exercise show substantial promise in the evaluation of peripheral arterial disease.

                  2577.     Investigations of Metabolic Differences Due to Differences in the Muscle Fiber Distribution by Using
                                31P-MRS at 3.0 T

Reinhard Rzanny1, Norman Stutzig2, Alexander Gussew1, Werner Alois Kaiser, Hans_Alexander Thorhauer2, Jürgen Reinhard Reichenbach1

1Institute for Diagnostical and Interventional Radiology,University Hospital Jena, Jena, Germany; 2Friedrich-Schiller-University Jena, Jena, Germany

31P-MRS at 3.0T was performed in the M. gastrocnemius of 6 volunteers with different sportive activities. Spectra were acquired before and during an exhaustive dynamic exercise. Different pH changes in different fiber types during the exercise cause a split of the Pi signal into 2 or 3 components whose intensity ratio can be used to estimate the fiber distribution in the muscle. In this study the PCr/ATP ratios during rest were compared with the intensity ratio of the Pi components after split with reference to its prediction of the expected muscle fiber distribution in athletes corre-sponding to their sportive activity.

                  2578.     Effect of Oral Creatine on Muscle Metabolism of Duchenne Muscular Dystrophy (DMD) by Phosphorus

Uma Sharma1, B Banerjee1, K Balasubramanian1, Veena Kalra1, N R. Jagannathan1

1All India Institute of Medical Sciences, New Delhi, India

Muscle energetics in Duchenne muscular dystrophy (DMD) patients was compared to controls and effect of oral creatine supplementation versus placebo was evaluated using phosphorus MRS and correlated with muscle strength and functional level. Phosphocreatine (PCr)/inorganic phosphate (Pi) and PCr/ â adenosine-tri-phosphate ratio were significantly lower in DMD compared to controls. A significant increase in creatine stores, marginal increase in manual muscle testing scores versus decrease in the placebo group suggested improvement in muscle strength on creatine supplementation. Creatine was found to be well tolerated and safe and a greater proportion of parents reported subjective improvement versus worsening on placebo.

                  2579.     Reliability of an Incremental Wrist Extension Exercise Protocol Using 31P-MRS for Measuring Metabolic
                                and Acid-Base Changes in the ECRB Muscle

Graydon Raymer1, Howard Green2, Greg Marsh3, Terry Thompson4

1Nipissing University, North Bay, Canada; 2The University of Waterloo, Waterloo, Canada; 3The University of Western Ontario, London, Canada; 4The Lawson Health Research Institute, London, Canada

The objective of this study was to assess the reliability of an incremental wrist extension exercise protocol using 31P-MRS for measuring the metabolic and acid-base response in the extensor carpi radialis brevis (ECRB) muscle. Female participants performed two identical wrist extension protocols. Peak power output, [ATP], [PCr], [Pi], and pHi were not different between trials. The coefficient of variation for the onset of a rapid decrease in pHi was 4.3 % and for the onset of a rapid increase in [Pi]/[PCr] was 6.3%. Therefore, an incremental wrist extension exercise protocol provides a reliable test of ECRB metabolic and acid-base status.

                  2580.     The Use of  31P MRS and Near-Infrared Spectroscopy (NIRS) to Assess the Kinetics of Children and Adults
                                at the Onset of Moderate Intensity Exercise

Jon Fulford1, Deborah Welford2, Joanne Welsman3, Neil Armstrong3, Alan Barker3

1Peninsula Medical School, Exeter, UK; 2University of Wales Institute Cardiff, Cardiff, UK; 3University of Exeter, Exeter, UK

31P and near-infrared spectroscopy were used to assess whether any changes can be detected between individuals due to age and/or sex at the onset of moderate intensity exercise. The kinetics of muscle PCr were found to be independent of age and sex. However, there is the suggestion of age-related variation of deoxy-haemoglobin dynamics, which may reflect an underlying imbalance between muscle O2 delivery and utilisation in children.

                  2581.     Detection of Skeletal Muscle Mitochondrial Dysfunction in Pulmonary Arterial Hypertension

Mirko Hrovat1, Chris Farrar2, James J. Tolle2, Patrick Gordan2, Gregory D. Lewis2, Paul Pappagianopoulos2, David Systrom2

1Mirtech, Inc., Brockton, Massachusetts, USA; 2Massachusetts General Hospital, Boston, Massachusetts, USA

This laboratory has recently described blunted systemic oxygen extraction at maximum exercise in pulmonary arterial hypertension (PAH). This was further investigated with 31P MRS. Results suggest that delayed limb skeletal muscle PCr recovery following submaximal exercise with normal arterial O2 content suggests an intrinsic abnormality of mitochondrial ATP synthesis and that PAH is more of a systemic disease than previously recognized.

                  2582.     Potential of 23Na-MRI in Muscular Sodium Channel Diseases

Armin Michael Nagel1, Marc-André Weber1, Frank Lehmann-Horn2, Karin Jurkat-Rott2, Lothar Rudi Schad

1German Cancer Research Center, Heidelberg, Germany; 2University Ulm, Germany

The purpose of this study was to show the feasibility of 23Na-MRI for the examination of patients with paramyotonia congenita (PC) and testing for specific therapies. A density adapted 3D Radial sampling scheme was used to measure the sodium concentration in the lower leg muscles of a patient with confirmed PC, a muscular sodium channelopathy, and of a healthy volunteer. After cooling one leg the sodium concentration in the patient’s cooled leg increased, whereas in the volunteer’s cooled leg no significant difference was observed. Furthermore a zinc medication was tested in the patient.

                  2583.     Chromium Oxide Nanoparticle Distribution: An MRI Study in Rats

Sanjay Annarao1, Deepak Gurbani2, K Jayalakshmi, Neeraj Sinha, Devendra Parmar2, Alok Dhawan2, Raja Roy1, C. L. Khetrapal1

1Centre of Biomedical Magnetic Resonance, Lucknow, India; 2Industrial Toxicology Research Centre, Lucknow, India

Distribution of Chromium oxide  nanoparticles  administered by intraperitoneal, intravenous, dermal, intramuscular and oral routes in rats was studied using Magnetic Resonance Imaging. The results indicate that Chromium oxide nanoparticles  produce contrast in images of thigh and testicular regions only when chromium oxide nanoparticles were administered dermally and intramuscularly. This indicates efficient absorption of chromium oxide nanoparticle by skin followed by its uniform distribution in the thigh and testicular region.

                  2584.     Muscle Metabolism and Acid-Base Status During Exercise in Work-Related Forearm Myalgia Measured
                                with 31P-MRS

Graydon Raymer1, Howard Green2, Don Ranney2, Greg Marsh3, 4, Terry Thompson, 34

1Nipissing University, North Bay, Canada; 2The University of Waterloo, Waterloo, Canada; 3The University of Western Ontario, London, Canada; 4The Lawson Health Research Institute, London, Canada

We studied the metabolic and acid-base status during exercise in the forearm of individuals with work-related myalgia (WRM) using 31P-MRS. We observed a lower pHi (P<0.05) and greater [Pi-]/[PCr]  (P<0.05). The onset of a faster decrease in pHi and the onset of a faster increase in [Pi]/[PCr] occurred at a lower relative power output in WRM (P<0.05). Data collected during the recovery from exercise showed a slower rate of restoration for pHi (P<0.05). In conclusion, our results suggest a reduced contribution of oxidative phosphorylation WRM, possibly a result of reduced blood flow and perfusion.

                  2585.     Inverse Correlation Between IMCL Content of the Human Calf Muscle and local Glycogen Synthesis Rate

Marinette van der Graaf1, Cees J.J. Tack1, Jacco H. de Haan1, Dennis W.J. Klomp1, Arend Heerschap1

1Radboud University Nijmegen Medical Center, Nijmegen, Netherlands

IMCL content in the soleus and gastrocnemius muscle was determined by 1H MRSI in twenty subjects belonging to four subgroups: young lean, elderly lean, young obese and elderly obese. In addition, local glycogen synthesis rate was measured by 13C MRS during a euglycemic-hyperinsulinemic clamp with 13C-1-glucose infusion. IMCL contents were higher in elderly (soleus: P<0.0001 and gastrocnemius: P<0.01) and obese subjects (P<0.01 for both muscles), and glycogen synthesis rate decreased with obesity (P<0.01). The principal finding was an inverse correlation between the mean IMCL content of the calf muscles and the local glycogen synthesis rate within the same muscle compartment (rs=-0.50, P<0.05).

                  2586.     1H MRS as Evaluation Tool of the Effects of β-Alanine Supplementation on the Muscle Carnosine
                                  Content in  Soleus and Gastrocnemius of 400m Sprinters

Harmen Reyngoudt1, Mahir Sinan Özdemir2, Andries Pottier1, Katrien Koppo1, Roger C. Harris3, J A. Wise4, Eric Achten1, Wim Derave1

1Ghent University Hospital, Ghent, Belgium; 2Ghent University, Ghent, Belgium; 3University of Chichester, Chichester, UK; 4Natural Alternatives International, San Marcos, USA

Carnosine is a dipeptide that is present in brain and skeletal muscle of humans and various animals. It is reported to play a buffering role in the physiological pH range during skeletal muscle contractions. In this study the effects of beta-alanine supplementation were evaluated by H MRS in a double-blind study. Carnosine has two well-discernable resonances at 7 and 8 ppm. Absolute quantification was performed in soleus and gastrocnemius using an external reference. Carnosine concentrations increased by 47% and 37% in soleus and gastrocnemius, respectively, following supplementation with beta-alanine. There was no significant increase (8%) in soleus and a smaller increase (16%) in gastrocnemius in the placebogroup. These experiments show that 1H MRS can be used to quantify carnosine in  a non-invasive way.

                  2587.     Effect of PH on CEST in Muscle

Elizabeth April Louie1, 2, Mark D. Does3, Daniel F. Gochberg2, Bruce M. Damon2

1Vanderbilt University Medical Center, Nashville, Tennessee, USA; 2Vanderbilt University , Nashville, Tennessee, USA; 3Vanderbilt University, Nashville, Tennessee, USA

Proton chemical exchange rates between molecules and water is pH sensitive. Intracellular pH of muscle decreases during intense exercise. A detection method to discern active muscle regions would be beneficial for studying muscle metabolism, diseases, and aging. Excised frog gastrocnemius muscle was used as a model for exercised muscle to determine the sensitivity of CEST for a pH change of 0.5. Preliminary results show a 1% difference in the magnetization transfer asymmetry plot of the amide resonance between the acidic and control muscles. Future studies include stimulating muscle to test whether CEST can detect glycogen concentration changes in muscle.

                  2588.     Implementation and Validation of Localized Constant-Time PRESS Sequence for Investigation of Skeletal
                                Muscle Metabolism

S. Sendhil Velan1, Kartik Narasimhan1, Richard G. Spencer2, Raymond R. Raylman1, Stephen E. Alway1

1West Virginia University, Morgantown, USA; 2NIH/National Institute on Aging, Baltimore, USA

We have implemented a novel single-voxel based two-dimensional constant-time (CT) spectroscopic method on a clinical 3T MRI/MRS scanner.  We have validated the technique with theoretical simulations and experimental results to achieve homonuclear decoupling and also to maximize the signal to noise ratio with optimal constant time. Finally we demonstrate the separation of olefinic protons within IMCL and EMCL and other resonances from these two lipid pools.

                  2589.     Muscle T2 Measurement and Gadolinium Uptake in Duchenne Muscular Dystrophy: Effect of Exercise in
                                DMD Boys and Comparison with Healthy Controls
 [Not Available]

Kieren Grant Hollingsworth1, Penny Garrood1, Benjamin S. Aribisala1, Daniel Birchall2, Michelle Eagle1, Kate Bushby1, Volker Straub1

1Newcastle University, Newcastle Upon Tyne, UK; 2Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, UK

The pelvic, thigh and calf muscles of 11 ambulant boys with DMD were assessed for T2 value and magnitude of gadolinium uptake before, and 4 days after, a challenging step test. 6 healthy adult volunteers acted as controls. For all muscles studied, T2 values and signal intensity increase with gadolinium were higher in the DMD children, reflecting inflammation and consequent increase in interstitial volume. The tibialis anterior muscles of both legs showed significantly greater enhancement 4 days post-exercise, and calf muscles showed a greater tendency to increased enhancement than thigh muscles. There were no significant changes in T2 value post-exercise.

                  2590.     In Vivo Characterization of Skeletal Muscle Fiber Ellipticity with Diffusion-Weighted MRI

Dimitrios C. Karampinos1, 2, Kevin F. King2, Bradley P. Sutton1, John G. Georgiadis1

1University of Illinois at Urbana-Champaign, Urbana, Illinois, USA; 2General Electric Healthcare, Waukesha, Wisconsin, USA

Diffusion Tensor Imaging of the skeletal muscle has shown that the secondary eigenvalue is consistently higher than the tertiary eigenvalue. It is also well-known from histology that the cross-section of skeletal muscle fibers is elliptical. In the present study, we propose a model which is consistent with the muscle histo-architecture and apply it to interpret DTI measurements obtained on sections of a human calf muscle. We demonstrate how DTI measurements can be used to produce maps of the postulated myofiber ellipticity and propose a hypothesis on the connection of this asymmetry to mechanical behavior upon contraction.

                  2591.     Deep Tissue Injury in Skeletal Muscle: Correlation Between Tissue Damage and Internal Strains as Studied
                                by MR Tagging, T2-Weighted MRI and FE Modeling

Anke Stekelenburg1, Karlien K. Ceelen1, Joost L.J Mulders1, Gustav J. Strijkers1, Cees W. Oomens1, Frank P. Baaijens1, Klaas Nicolay1

1Eindhoven University of Technology, Eindhoven, Netherlands

Pressure ulcers are localized areas of tissue necrosis caused by compression of soft tissues. The underlying mechanisms of deep pressure ulcers are poorly understood. In the present study the correlation between the location of tissue damage, measured by T2-weighted MRI, and the location of high strains, determined by MR tagging and FE modeling, was investigated. The MR tagging experiments were used to validate the FE model. It was demonstrated that the amount of damage increased with increasing shear strain. This demonstrates the importance of large deformations, besides ischemia, in the etiology of deep pressure ulcers.

                  2592.     Velocity Encoded-Phase Contrast MRI Reveals  in Vivo  Tissue Dynamics of the Human Medial
                                Gastrocnemius  During Isometric Contraction

Ryuta Kinugasa1, Dongsuk Shin2, John A. Hodgson2, Reggie V. Edgerton2, Shantanu Sinha1

1University of California San Diego, San Diego, California , USA; 2University of California Los Angels, Los Angels, California , USA

Using Velocity-encoded phase-contrast MR imaging, the velocity and displacement along the length of both the deep and superficial aponeurosis of the medial gastrocnemius were determined during sub-maximal voluntary isometric contractions. Contrary to present belief in literature, instead of stretching homogenously along their lengths, the displacement of different regions of the two aponeuroses were heterogeneous during isometric contraction. Such detailed information is imperative for proper modeling of the human musculoskeletal system.

                  2593.     Myofiber and Microvasculature Architecture of Human Calf Muscle Alteration in Passive Dorsiflexion

Dimitrios C. Karampinos1, 2, Kevin F. King2, Danchin Chen1, Lucija Rakocevic1, John G. Georgiadis1

1University of Illinois at Urbana-Champaign, Urbana, Illinois, USA; 2General Electric Healthcare, Waukesha, Wisconsin, USA

We combine Diffusion-Weighted MRI techniques (IVIM and DTI) and employ a home-made MRI-compatible cradle for leg immobilization, to quantify in vivo changes in muscle fiber architecture and perfusion following passive dorsiflexion of the foot. The resulting stretching of the gastrocnemius muscle is associated with a significant decrease in local perfusion, and a modest decrease in pennation angle and T2, all consistent with measurements obtained with various imaging modalities.

                  2594.     A Strain Analysis of the Lower Leg During Ankle Rotation Using HARP at 3 Tesla

Michael A. Green1, Simon C. Gandevia1, Lynne E. Bilston1

1Prince of Wales Medical Research Institute, Sydney, Australia

A quantified strain analysis of muscle motion in the distal leg of healthy volunteers has been performed using the HARP imaging technique with a 3T full body scanner. Principal strain measurements have been achieved by examining tagged images of the muscles before and after rotation about the ankle for plantarflexion and dorsiflexion. Quantified results have shown large strains in the medial gastrocnemius and soleus. Principal strain directions have also been measured and may provide more information of intramuscular properties relating to muscle fascicle direction and pennation angle.

                  2595.     Quantitative T2 Maps in Idiopathic Inflammatory Myopathy:  Correction for Fatty Involution of Muscle

Lawrence Yao1, Neville Gai2

1NIH, Bethesda, Maryland, USA; 2NIH, USA

Active muscle disease in patients with idiopathic inflammatory myopathy may be quantified with bulk T2 measurements. We illustrate an improved clinical T2 MR measurement that is corrected for muscle fat fraction. This method may be more valid in cases of advanced or chronic muscle damage.

                  2596.     Monte Carlo Simulation of Muscle Diffusion: Effect of SNR

Bruce M. Damon1, Zhaohua Ding1, Adam W. Anderson1

1Vanderbilt University, Nashville, Tennessee, USA

Diffusion-tensor MRI (DT-MRI) is a promising tool for structural characterization of muscle, including fiber tracking.  Partial volume artifacts due to intramuscular fat deposition require the development of new tracking algorithms capable of distinguishing between muscle and fat diffusion properties on the basis of readily measurable MR parameters.  The purpose of this study was to test the dependence of the muscle and fat DT on the signal-to-noise ratio (SNR), using Monte Carlo simulations.  We found that muscle DT-MRI has high SNR requirements and that fractional anisotropy cannot distinguish between fat and muscle at typical SNR values.

                  2597.     Ankle Orientation Alters Bulk Susceptibility and Residual Dipolar Couplings During Plantar Flexion and
                                Dorsiflexion of Skeletal Muscle

S. Sendhil Velan1, Nicholas Said1, Kartik Narasimhan1, Richard G. Spencer2, Raymond R. Raylman1, Vazhaikkurichi M. Rajendran1, Stephen E. Alway1

1West Virginia University, Morgantown, USA; 2NIH/National Institute on Aging, Baltimore, USA

Quantification of skeletal muscle MRS spectra is influenced by bulk magnetic susceptibility shifts resulting in variable separation between intramyocellular and extramyocellular lipid resonances in different muscle compartments.  In addition certain metabolites exhibit residual dipolar couplings between nuclei altering the multiplicity and amplitudes.  Both effects are dependent upon the ankle orientation which alters the muscle fibers with respect to the main magnetic field direction.  In this work we have assessed the nature of the bulk susceptibility and residual dipolar interactions through the effect of geometric changes which can be accounted for in a reproducible manner, permitting improved quantification and reproducibility.

                  2598.     Ultrashort-T2 and Magic-Angle Contrast: A Comparison

Juergen Rahmer1, Peter Börnert1

1Philips Research Europe, Hamburg, Germany

Certain types of highly ordered tissues, such as tendons, ligaments, or peripheral nerves, show a variation in T2 relaxation time depending on the orientation with respect to the external field B0. The effect is caused by residual dipolar coupling that vanishes at an angle of 54.7 degrees, called the magic angle. Measuring an anatomy at different angles towards the external field allows identification and selective visualization of tissue components that are subject to dipolar effects. Furthermore, information about the microscopic fiber orientation can be obtained. While the arising contrast can be termed magic angle contrast, ultrashort TE (UTE) imaging enables the visualization of a general short-T2* contrast caused by dipolar and other decay mechanisms. In this work, both contrasts are acquired to characterize short-T2 components in tendons and bones of the hand, using 3D isotropic data measured at UTE and a later echo time at various orientations.


Lung MRI

Hall D                                   Thursday 13:30-15:30                                                                                                                                           

                  2630.     Improved Visualization of Delayed Contrast Agent Bolus Onset in Pulmonary Perfusion MRI

Frank Risse1, Michael Puderbach1, Monika Eichinger1, Hans-Ulrich Kauczor1, Wolfhard Semmler1

1Deutsches Krebsforschungszentrum, Heidelberg, Germany

The temporal information of three-dimensional (3D) dynamic contrast-enhanced MRI is not usually used to read lung perfusion images. Subtraction images are generated instead, but this might mask perfusion in case of a delay. The aim, therefore, is to demonstrate a simple analysis strategy by computing parameter maps for the lung without omitting temporal information, thus enabling improved visualization of the results. It has been shown that subtraction images might mask the real underlying perfusion conditions. Based on the results, perfusion was classified into five subgroups.

                  2631.     Whole-Body MR Examination for M-Stage Assessment in Non-Small Cell Lung Cancer: How to Use
                                 Whole-Body Diffusion-Weighted Imaging as Compared with Integrated FDG-PET/CT

Yoshiharu Ohno1, Yumiko Onishi, 12, Hisanobu Koyama1, Munenobu Nogami, 12, Daisuke Takenaka1, Takeshi Yoshikawa, 13, Sumiaki Matsumoto1, Kazuro Sugimura1

1Kobe University Graduate School of Medicine, Kobe, Japan; 2Institute of Biomedical Research and Innovation, Kobe, Japan; 3Konan Hospital, Kobe, Japan

In this study, we attempted to validate the hypothesis that whole-body MR imaging with DWI has potential as an alternative technique for the detection of distant metastases in NSCLC patients with a capability similar to that of integrated FDG-PET/CT.  To this end, we prospectively and directly compared the capability of whole-body MR imaging with and without DWI and of integrated FDG-PET/CT for M-stage assessment in NSCLC patients, and to determine the utility of whole-body DWI as a component of whole-body MR examination for detection of metastases.

                  2632.     Pulmonary MRI vs. Thin-Section MDCT: Capability for Nodule Detection and Diagnosis and for
                                 Assessment  of Influence to Survival

Hisanobu Koyama1, Yoshiharu Ohno1, Hideaki Kawamitsu2, Atsushi Kono1, Daisuke Takenaka1, Masahiko Fujii2, Kazuro Sugimura1

1Kobe University Graduate School of Medicine, Kobe, Japan; 2Kobe University Hospital, Kobe, Japan

Since 1997, several investigators have reported the capability of pulmonary MRI for nodule detection as compared with CT, and tried to demonstrate possibility for substitution to CT.  However, no direct comparison between pulmonary MRI and MDCT have been reported.  We hypothesized that pulmonary MRI has potential for detect and diagnose pulmonary nodules without significant degradation of detection rate for malignant nodules, diagnostic accuracy and survival rate, when compared with MDCT. The purpose of our study was to compare capability for nodule detection and diagnosis and for affection to survival between pulmonary MRI and MDCT.

                  2633.     The Use of Color Intensity Projections (CIPs) for Visualizing Pulmonary Perfusion Parameters with
                                Preservation of Anatomy

Jan G. Korporaal1, 2, J. Tim Marcus1, Heleen Rietema, Keith S. Cover1, Anton Vonk Noordegraaf

1VU University Medical Center, Amsterdam, Netherlands; 2Utrecht University Medical Center, Netherlands

In dynamic contrast-enhanced pulmonary perfusion, the Color Intensity Projection (CIP) is constructed by pixel: the hue (wavelength of color) is determined by the time to peak enhancement, the saturation of color by the contrast enhancement ratio, and the brightness by the maximum signal intensity over time. The feasability of CIP was demonstrated in a patient with emboli and a patient with obstructed left pulmonary artery. The CIP yields one comprehensive functional perfusion image, where underlying anatomic structures of well-perfused lung areas and blood vessels are automatically distinguishable by high saturation and brightness.

                  2634.     Comparison of Pixel-By-Pixel Compartment Modeling and Deconvolution Analysis for Pulmonary
                                 Perfusion Measurements

Michael Ingrisch1, Ulrike Attenberger1, Steven Sourbron1, Olaf Dietrich1, Frank Risse2, Maximilian Reiser1, Christian Fink3

1Klinikum Großhadern, Munich, Germany; 2Deutsches Krebsforschungszentrum, Heidelberg, Germany; 3Klinikum Mannheim, Mannheim, Germany

Dynamic contrast-enhanced MRI allows the assessment of pulmonary perfusion. We investigate the feasibility of a pixel-by-pixel analysis of pulmonary perfusion using a one-compartment model in healthy volunteers. The results were compared with a more commonly used deconvolution approach. The results indicate that a one-compartment-model describes the data sufficiently and, in agreement with literature, yields higher flow values than deconvolution analysis. 

                  2635.     Comparison of Two Gadolinium Contrast Agents for Lung Perfusion MRI

Paul Armitage1, Neil Woodhouse2, David Kiely3, Paul Griffiths2, Jim M. Wild2

1University of Edinburgh, Edinburgh, UK; 2University of Sheffield, Sheffield, UK; 3Royal Hallamshire Hospital, Sheffield, UK

With the development of faster imaging sequences, MR contrast enhanced lung perfusion imaging has become feasible in the clinical setting and shows great promise as a non-ionizing alternative to a nuclear scintigraphy lung perfusion scan.  In this work, a visual and quantitative comparison is made between perfusion maps of the lung acquired using two different gadolinium-based paramagnetic contrast agents.

                  2636.     Comparison of High-Resolution and Time-Resolved MRA in a Rabbit Model of Pulmonary Embolism
                                at 1.5 and 7 Tesla

Jaime Mata1, Ugur Bolzar1, John Mugler III1, Colleen Schamber1, Wilson Miller1, Stuart Berr1, Klaus Hagspiel1

1University of Virginia, Charlottesville, USA

High magnetic-field strengths potentially allow significant improvements for imaging many regions of the body due to the increase in signal-to-noise ratio, which can be traded for higher spatial resolution or shorter acquisition times. However, in the lungs, with their large number of air-tissue interfaces that result in strong localized field gradients induced by the magnetic-susceptibility differences, the use of magnetic resonance imaging at higher fields („d3.0T) may be limited. We evaluated the feasibility of using time-resolved and high-resolution contrast-enhanced MRA at 7T for characterizing an animal model of pulmonary embolism and compared the results with the same techniques at 1.5T.

                  2637.     Validation of Quantification of Regional Pulmonary Blood Flow (PBF) Via Contrast Enhanced MRI Using
                                Non-Linear Corrected AIF with H215O PET

Daniel Neeb1, Rainer Peter Kunz1, Sebastion Ley2, Gabór Szábo3, Ludwig G. Strauss2, Hans-Ulrich Kauczor2, Karl-Friedrich Kreitner1, Wolfgang G. Schreiber1

1Mainz University Medical School, Mainz, Germany; 2German Cancer Research Center (DKFZ), Heidelberg, Germany; 3University of Heidelberg, Heidelberg, Germany

Nine healthy pigs were examined using MRI and H215O PET imaging. Calculation of PBF was based on a model of freely diffusible tracers (PET) and indicator dilution theory (MR). A sequence-dependent correction for non-linearity in the AIF was developed for the MR data. ROI analysis confirmed a statistically highly significant correlation (p < 0.001) between blood flow values obtained from PET and MR and a good linear relation when utilizing the proposed AIF correction methdology. Deviations from the ideal case appear to be explained by the study design (delay between measurements) and methodologic aspects (respiratory status, different slice thickness).

                  2638.     Utility of the Optical Flow Method for Motion Tracking in the Lung

Chun Xu1, Ke Zhang, 12, Lawrence Dougherty1, 1, Abram Voorhees1, 1, Qun Chen, 12

1; 2New York University, New York, New York, USA

MRI spirometry is technique that has been demonstrated to non-invasively measure pulmonary function on a regional basis. Using real-time imaging of the lung during forced breathing maneuvers, this method is able to calculate regional physiologic measures, such as FVC, FEV1, and the time constant tau. Relevant for assessing heterogeneous pulmonary disorders, this technique has shown the ability to examine lung function with a resolution currently unavailable from commonly used non-invasive procedures. This paper examines the improved motion tracking results of using the optical flow method to assess lung deformation.

                  2639.     Time Resolved Lung Ventilation Imaging by Fourier Decomposition

Michael Deimling1, Vladimir Jellus1, Bernhard Geiger, Christophe Chefd'hotel

1Siemens Medical Solutions, Erlangen, Germany

Lung ventilation is measured without any endogenic media by using the density variation of registered lung tissue. A very fast SSFP sequence is used to generate a time-resolved 2D-lung data stack. Fourier transform along the time axes will allow the separation of breathing or ventilated regions from disturbing signals due to the pulsating blood within the lung tissue. The description of the pathologic breathing pattern, seems possible with this spectral decomposition technique.

                  2640.     Quantitative Assessment of Deposition Patterns of Inhaled Particulate Matter by MRI

Miriam Scadeng1, Ellen C. Breen1, G Kim Prisk1, David J. Dubowitz1, Chantal Darquenne1

1UCSD, San Diego, California , USA

Exposure to airborne particulate matter and its implications in human health are a major concern as more evidence links air pollution with morbidity and mortality. Understanding of the fate of aerosols in the human lung is also important in medical applications such as inhalation drug therapy, and threats of biological warfare. We describe a quantitative technique to determine the distribution of airborne particles in the respirable range in an animal model using MRI that could be used to study healthy or diseased lungs.

                  2641.     Method for Correction of Breathing-Dependent Signal Changes in Dynamic Lung Oxygen-Enhanced MRI –
                                Improved Sensitivity in Smokers

Deirdre Maria McGrath1, Josephine Naish1, Chris Taylor1, Charles Hutchinson1, Geoff Parker1

1University of Manchester, Manchester, UK

Oxygen-enhanced lung MRI is hampered by intrinsically low proton density, the large susceptibility differences caused by the air-tissue interfaces, and respiratory and cardiac motion. To avoid the effects of breathing motion in dynamic studies breath-holding, gating or post-registration is required. Registration is preferable, as gating is not ideal for maintaining temporal resolution and breath-holding may distort the processes being measured, and is not well tolerated. We present a novel corrective method for breathing-dependent signal changes applied to data from a free-breathing dynamic protocol with post-registration, and demonstrate how the correction improves sensitivity of the oxygen wash-in time characteristic in smokers.

                  2642.     SSFP Based High Resolution 19F Imaging of the Rat Lung Ex Vivo with FC84

Dominik von Elverfeldt1, Philipp Emerich1, Julia Weigel1, Dominik Paul1, Daniel Steinmann1, Matthias Schneider1, Hanna Runck1, Claudius Stahl1, Josef Guttmann1, Jochen Leupold1

1University Hospital Freiburg, Freiburg, Germany

Besides its therapeutic effect partial liquid ventilation using perfluorocarbons has the potential of susceptibility reduced lung imaging and the possibility to monitor oxygen turnover. So far these options have been used in pig lungs at 1.5 T using 19F imaging. In the rat lung the beneficial susceptibility effect on 1H MRI using PLV with water-perfluorcarbon emulsions was shown. This work demonstrates the potential of a SSFP based high resolution sequence in 19F MRI on excised rat lungs at 9.4 T.


Body Fat & Obesity

Hall D                                   Thursday 13:30-15:30                                                                                                                                           

                  2696.     Variations in Basal Liver and Muscle Lipid Levels in Type II Diabetes Determined Using 1H MRS

Mary C. Stephenson1, Emily Leverton1, Eric Y H Khoo1, Simon M. Poucher2, Carsten Liess2, Andrew J. Lockton2, Lars Johansson3, 4, Jan W. Eriksson3, 5, Peter Mansell1, Ian A. MacDonald1, Peter G. Morris1

1University of Nottingham, Nottingham, UK; 2AstraZeneca, Macclesfield, UK; 3AstraZeneca, Mölndal, Sweden; 4Uppsala University Hospital, Uppsala, Sweden; 5Sahlgrenska University Hospital, Gothenburg, Sweden

Evidence suggests that insulin resistance in type II diabetes is associated with excessive lipid levels in tissues such as the liver and skeletal muscle.  Here we assess the reproducibility of basal lipid levels in the liver and total and intra myo-cellular lipid (IMCL) levels in the calf muscle in both type II diabetic and healthy subjects. Variation in these levels in both groups, measured over the period of a month, was larger than expected from that measured in a single session (up to 3-fold larger in the liver) thus indicating biological changes in baseline levels.

                  2697.     Variations in Basal Liver and Muscle Glycogen in Type II Diabetes Determined Using 13C-MRS

Emily Leverton1, Mary C. Stephenson1, Eric Y H Khoo1, Simon M. Poucher2, Carsten Liess2, Andrew J. Lockton3, Lars Johansson4, 5, Jan W. Eriksson4, 6, Peter Mansell1, Ian A. MacDonald1, Peter Gordon Morris1

1University of Nottingham, Nottingham, UK; 2AstraZeneca , Macclesfield, UK; 3AstraZeneca, Macclesfield, UK; 4AstraZeneca , Mölndal, Sweden; 5Uppsala University Hospital, Uppsala, Sweden; 6Sahlgrenska University Hospital, Gothenburg, Sweden

The reproducibility of measurement of glycogen concentration in liver and calf muscles in healthy and Type 2 diabetic subjects using 13C-MRS has been investigated. Variation in between successive scans on a single occasion was studied to find repeatability of the measurement and variation over timescales varying from 5 days to 4 weeks was studied to investigate biological variation. Biological variation occurred in both liver and calf muscle glycogen over a week in diabetic subjects. In the healthy group liver glycogen varied biologically over 2 weeks and calf glycogen did not change significantly at any time throughout the study.

                  2698.     Non-Invasive Imaging of Differing Physical Forms of Dietary Fat During Digestion in Humans

Caroline Louise Hoad1, Luca Marciani1, David Gray1, Ian Fisk1, Sakunkhun Makkhun1, Elisa Placidi1, Eleanor F. Cox1, John J. Totman1, Robin C. Spiller1, Penelope A. Gowland1

1University of Nottingham, Nottingham, UK

A 3D T1-weighted fat only excitation imaging sequence was used to determine the fate of four different sunflower oil meals in vivo in the gastro-intestinal (GI) tract.  Four different volunteers were each serially scanned on a single occasion.  A sunflower seed meal was visible as particulates on the fat only images in the stomach, and as increased signal intensity in the small bowel and ascending colon.  Three different sunflower oil-in-water emulsion meals (one natural and two processed) all showed a different fat distribution in the stomach, with phase separation of one of the emulsions occurring soon after the meal was ingested.

                  2699.     Short-Term Dietary Effects on Liver Lipids Measured with 3T MRS

Susan Moyher Noworolski1, Kathleen Mulligan1, Michael Wen1, Laurie Herraiz1, Melissa Weinberg1, Grace A. Lee1, Jean-Marc Schwarz, 12

1UCSF, San Francisco, California , USA; 2Touro University, Vallejo, California , USA

Short-term effects on liver lipids were evaluated with 3T  1H MRS. Six subjects underwent seven days of a simple-sugar diet and seven days of an isocaloric, complex-carbohydrate diet as inpatients in a metabolic ward. A respiratory-motion corrected time series of 20cc single voxel spectra were acquired in the liver (TR/TE=2500/37ms). All subjects had higher liver lipids:water after the simple-sugar diet when compared to the complex-carbohydrate diet (median=136%, range=110-370%, p=0.031. This suggests that the simple-sugar diet may be associated with an increase in liver lipids which is detectable by 1H MRS after periods as short as seven days.

                  2700.     Effect of 1H MRS Sequence on Absolute Quantification of Hepatic Lipid

Gavin Hamilton1, Mike S. Middelton1, Mark Bydder1, Takeshi Yokoo1, Nicholas Cameron Pinto1, Joel E. Lavine1, Claude B. Sirlin1

1UCSD, San Diego, USA

We examine the effect sequence choice makes on the hepatic fat measured by 1H MRS. PRESS and STEAM spectra were collected from an animal fat phantom and in-vivo from the liver of 49 subjects. In the phantom, we found that the fat peaks showed non-exponential decay in the PRESS sequence.  In vivo, we found that the PRESS sequence overestimated the lipid peak area with respect to STEAM, though this overestimate appeared systematic.

                  2701.     Effect of a Physical Exercise Program on Intrahepatic and Visceral Lipids in Obese People - A Pilot Study

Michael Ith1, Cecile Bachmann1, Philipp Scacchi1, Roland Kreis1, Nadine Messerli-Buergy1, 2, Monica Zehnder1, Katharina Meyer1, Emanuel R. Christ1, Kurt Laederach-Hofmann1, 3, Chris Boesch1

1University Bern, Bern, Switzerland; 2University College of London, London, UK; 3University Trier, Trier, Germany

Obesity, accumulation of visceral adipose tissue and increased intrahepatocellular lipids (IHCL) are linked, however the underlying pathophysiological mechanisms are not yet fully understood. Besides testing the methodology, this study aimed at the determination of these parameters prior and after a 3-month intervention of diet and exercise as well as on BMI and physical performance. The results show an increase in physical fitness in combination with a decrease of IHCL, BMI and visceral adipose tissue. The improvement in patients who were involved in physical exercise in combination with dietary counseling tended to respond better than those with dietary counseling only.

                  2702.     High Resolution Measurement of Hepatic Fat Volume Fraction in a Single Breathhold

Glen Morrell1, Paul Hopkins1, June Taylor1

1University of Utah, Salt Lake City, USA

High resolution multislice hepatic fat volume fraction measurement was performed in five obese volunteers using a three-point Dixon method, with all three echoes obtained during a single sequence repetition.  The entire liver was imaged in about 13 seconds, easily within a single breathhold.  Measured hepatic fat volume fraction correlated strongly with body mass index.

                  2703.     Intrinsic Water-Suppression in TIDE-BSSFP Applied for Quantification and Differentiation of Adipose

Gregor Sommer1, Ute Ludwig1, Tobias Baumann1, Dominik Paul1

1University Hospital Freiburg, Freiburg, Germany

MRI has the ability to determine the distribution of visceral and subcutaneous fat reliably without radiation exposure. The inherently bright fat-signal in bSSFP sequences (balanced Steady State Free Precession) in combination with frequency selective tissue suppression, such as FS-TIDE (fat suppressed-Transition into Driven Equilibrium), offers high potential in this context. This work introduces intrinsic water suppressed TIDE-imaging (WS-TIDE) in vivo and gives an estimate on its applicability as a tool for adipose tissue quantification in obese patients.

                  2704.     Analysis of Composite Pulse Schemes for Abdominal Fat Suppression

Andrew James Wheaton1, Mitsue Miyazaki, 12, Shinichi Kitane3

1Toshiba Medical Research Institute, Mayfield, Ohio, USA; 2Toshiba America Medical Systems, Tustin, California , USA; 3Toshiba Medical Engineering Co., Tochigi, Japan

Composite pulse spectral-saturation schemes are known to be more B1- and T1-robust than single pulse approaches.  We investigated 2- and 3-pulse composite schemes as alternatives to STIR for fat saturation in 3D abdominal imaging.  Numerical Bloch solutions were modeled for STIR, 2-pulse, and 3-pulse schemes for a range of δB1 and δT1.  Model data were combined with experimental data to calculate the expected fat sat performance, time-efficiency, and SAR-efficiency of each technique.  The 3-pulse scheme offered better B1-robustness and performance than 2-pulse or STIR, but marginal SAR- and time-efficiency.  The 2-pulse scheme offered a good balance of performance and efficiency.

                  2705.     Improvement of IDEAL Fat-Water Separation at Large FOV in the Presence of Gradient Non-Linearity
                                and Severe Field Inhomogeneities

Jong-Kai Hsiao1, 2, Hing-Chiu Chang2, Hon-Man Liu1

1National Taiwan University, Taipei, Taiwan; 2GE Healthcare Taiwan, Taipei, Taiwan

IDEAL produces robust fat and water separation by iteratively finding the optimal field map, which is compatible with multi-coil acquisition. The IDEAL method is, however, problematic in the presence of incorrect convergence of field map solutions. A 2-D linear field map estimation with region growing improves the IDEAL algorithm's immunity to field inhomogeneity. In this work, we propose another option using phase changing during different TEs to semi-automatically estimate field map in regions with severe field inhomogeneities. The proposed scheme is compatible with gradient nonlinear correction near the edge regions of the FOV, hence could improve the performance of IDEAL in larger FOV applications such as the abdomen.

                  2706.     Effect of Inulin on Adipose Tissue Deposition and on Appetite Regulation  [Not Available]

Jelena Anastasovska1, Gina Julieth Sanchez Canon1, Po-Wah So1, Louise E. Thomas1, Amy H. Herlihy1, Jan Van Loo2, Neena Modi3, Jimmy D. Bell1, Gary Frost4

1Hammersmith Hospital, Imperial College London, London, UK; 2BENEO-Orafti Group, Tienen, Belgium; 3Chelsea & Westminster Hospital, Imperial College London, London, UK; 4University of Surrey, Guildford, UK

Effects of different diet constituents on obesity and related diseases are currently being investigated. Inulin is a natural plant ingredient with prebiotic properties. In this study, we investigate the effects of inulin on adiposity and appetite regulation. Using MRI and MRS we show that dietary intake of inulin significantly reduces the weight gain and adiposity as well as the intrahepatocellular lipid content in mice. In addition, we show that inulin can modulate total energy intake, possibly through changes in central appetite regulation, as assessed by MEMRI. Inulin appears to favourably modulate appetite regulation, hepatic lipid metabolism and adipose tissue content


Assessing Tumor Response to Therapy

Hall D                                   Thursday 13:30-15:30                                                                                                                                           

                  2791.     Evaluation of Early Docetaxel Effects in MCF7 Xenografts Using HR MAS, in Vivo MRS, DCE-MRI
        and ADC-Mapping

Else Marie Huuse1, Line Rørstad Jensen1, Pål Erik Goa1, 2, Steinar Lundgren2, 3, Ingrid Synnøve Gribbestad1, Tone Frost Bathen1

1The Norwegian University of Science and Technology (NTNU), Trondheim, Norway; 2St. Olavs Hospital, Trondheim, Norway; 3NTNU, Trondheim, Norway

Sensitive methods to assess early treatment response are needed to obtain individualized patient protocols depending on the biological characterization of tumors. DCE-MRI, ADC-mapping, in vivo MRS and ex vivo HR MAS MRS of tissue samples combined with multivariate data analysis, have been used to study changes during tumor progression and early effects of docetaxel in MCF7 xenografts. Our findings indicate that docetaxel treatment cause a significant increase in water diffusion and distinct differences in the in vivo and ex vivo metabolite profiles of controls, docetaxel treated and tumors in early stage of progression.

                  2792.     Methodological Improvements in Multi-Centre Phase I DCE-MRI Studies of Novel Antivascular Drug
                                Treatments: Implications for Reproducibility and Quality Assurance

N. Jane Taylor1, David J. Collins2, James A. d'Arcy2, J. James Stirling1, Toni Wallace2, Dow-Mu Koh2, Anwar R. Padhani1

1Mount Vernon Hospital, Northwood, UK; 2Royal Marsden Hospital, Sutton, UK

In order to optimise DCE-MRI for use in multicentre studies, we have developed an imaging procedure suited for this purpose (3D acquisition, good quality assurance and control (QA/QC), using attainable sequence parameters for different machines, as linear relationship as possible between the signal intensity and the contrast agent concentration, quantification of tissue T1 relaxation rates using the Wang method.) These modifications have improved transfer constant reproducibility by 30% compared with a previous 2D acquisition technique when performed at 2 sites. We recommend these modifications in order to improve test performance for assessing novel antivascular therapies in multicentre clinical trials.

                  2793.     MRI Guided Anti-Tumor Therapy with Liposomal Prednisolone Phosphate

Ewelina Kluza1, Daisy van der Schaft1, Willem Mulder2, Raymond M. Schiffelers3, Gert Storm3, Gustav J. Strijkers1, Klaas Nicolay1

1Eindhoven University of Technology, Eindhoven, Netherlands; 2Mount Sinai School of Medicine, New York, USA; 3Utrecht University, Utrecht, Netherlands

Therapy with liposomal prednisolone phosphate strongly inhibits tumor growth. Since the exact mechanism of this anti-tumor action remains unclear, we decided to perform MRI-guided therapy to bring further insight into the observed effects. Several MRI methods were applied.  Diffusion MRI and T2 mapping did not show any sighificant changes in the parameters masured throughout the therapy. However, contrast enhanced T1-weighted imaging using RGD-targeted paramagnetic liposomes as a contrast agent showed significantly stronger signal enchancement in treated tumors compared to the control group. Massive contrast agnet accumulation suggests increased vascular permeability caused by the therapy.

                  2794.     Development and Characterisation of a Tumour Specific Contrast Agent for In Vivo Imaging of
                                 Therapeutic Response

Tammy Louise Kalber1, Nazila Kamaly, Stephanie Anne Higham1, Amy H. Herlihy1, Andrew D. Miller, Jimmy D. Bell1

1Hammersmith Hospital, Imperial College London, London, UK

A novel colchicine based conjugated gadolinium contrast agent (Gd.DOTA.Colchicinic acid) was synthesised and tested for its T1 relaxation ability and its efficacy as a therapeutic agent in vitro and in vivo. Phantoms and biological  in vitro and in vivo data showed it to be an effective signal enhancer achieving a maximum of 96% T1  reduction when compared to controls. T1 enhancement was apparent in tumour bearing mice within 2 hours and was unchanged at 24 hours highlighting intratumoural changes in morphology. Histology confirmed that conjugation of Gd.DOTA reduced toxicity, but did not lose its efficacy as a tubulin binding agent.

                  2795.     Cisplatin Treatment Monitoring by Sodium MRI Relaxometry at 4.7 T in Colorectal Tumors Implanted
                                 on Mice

Carole D. Thomas1, 2, Mihaela Lupu1, 2, Christine Walczak1, 2, Andreas Volk1, 2, Joël Mispelter1, 2

1Institut Curie, Orsay, France; 2INSERM-U759, Orsay, France

Sodium MRI in conjunction with relaxometry may monitor non-invasively structural changes in tumors due to the quadrupolar characteristics of sodium nuclei. The purpose of this work was to follow the effect of cisplatin on colorectal tumors implanted in nude mice. Sodium MRI revealed necrosis, with a high contrast, due to the diminished cellular density and consequently an increase in extracellular sodium. Sodium relaxometry revealed a T2 increase consequently to cisplatin treatment as compared to control. The authors suggested that the relaxation constants modification was due to the cellular shrinkage induced by the apoptotic process triggered by cisplatin treatment.

                  2796.     NMR Visible Cholesterol Content Predicts Ultimate Treatment Response in HCT-116 Xenografts Treated
                               with Flavopiridol, CPT-11 or the Combination

Jin-Hong Chen1, Yuhsin V. Wu1, Rachael O’Connor1, Bernadette U. Laxa1, Penelope DeCarolis1, Elliott R. Brill1, Samuel Singer1

1MSKCC, New York, New York, USA

Current methods for assessing therapeutic response are largely based on changes in tumor size after multiple cycles of chemotherapy and are often inaccurate. This study uses an ex-vivo NMR biomolecular analysis of tumor tissue following a single cycle of chemotherapy to predict ultimate therapeutic effect in a human-colon-cancer (HCT-116) xenograft model. The HCT-116 tumor responds to the treatment of cpt-11 or the combination of cpt-11/flavopiridol but only slightly to the flavopiridol alone. The NMR detected cholesterol measured 4 days after the first drug dose correlates with response and predicts ultimate treatment outcome in this model xenograft prior to any discernable change in tumor size. These results suggest that NMR visible cholesterol serves as an early biomarker of therapeutic response and would provide a more efficient approach for selecting active drug regimes.

                  2797.     Evaluation of the Effects of Herpes Simplex Virus Thymidine Kinase (HSV-TK) Overexpression on
                                5-Fluoro-2'-Deoxy-Uridine Metabolism in Tumor Xenografts Using In Vivo 19F MR Spectroscopy

Khushali Kotedia1, Ellen Ackerstaff1, Ligang Xing1, C. Clifton Ling1, Gloria C. Li1, Jason A. Koutcher1

1Memorial Sloan Kettering Cancer Center, New York, USA

Increased thymidine kinase (TK) activity may facilitate conversion of 5-fluoro-2’-deoxy-uridine (FUdR) to 5-fluorouracil (5-FU).  In vitro growth inhibition studies showed that expression of HSV-TK/GFP fusion protein increased sensitivity to FUdR minimally in the rat prostate carcinoma model R3327-AT and three orders of magnitude in the rat glioma model RG2.  Fluorescence imaging validated HSV-TK/GFP expression in vivo. In vivo 19F MRS of R3327-AT and R3327-AT/TK tumors demonstrated the conversion of FUdR to 5-FU whose catabolites appeared quickly. No fluoronucleotides were detected.  RG2 and RG2/TK are being investigated to determine if their in vitro sensitivity to FUdR changes FUdR metabolism in vivo.

                  2798.     Measuring ADC Reductions as an Early Response to Chemotherapeutic Treatment

Lauren Jean Bains1, Jennifer H. Baker2, Andrew I. Minchinton2, Stefan Alexander Reinsberg1

1University of British Columbia, Vancouver, Canada; 2British Columbia Cancer Research Centre, Vancouver, Canada

MRI and histochemistry were used to monitor the response of colorectal cancer xenografts to treatment with tirapazamine, a hypoxia activated prodrug.  The effect of tirapazamine on tumour diffusion characteristics was measured by mapping apparent diffusion coefficient (ADC)  before and after treatment.  Once ADC maps were aligned with BrdU/haematoxylin images of necrosis, it was found that tirapazamine caused a decrease in ADC in both necrotic and non-necrotic tissues.      Mean tumour ADC was elevated in tumours which did not fully respond to treatment, indicating that ADC may be used as a predictor of tumour response to this hypoxia targeting agent.

                  2799.     Quantitative Assessment of Glioma Therapy Efficacy Based on Diffusion Isotropy and Anisotropy
 [Not Available]

Priya Goel1, Matthias Karrasch2, Jan den Hollander1, James M. Markert1, Louis Burt Nabors1, Narasimha Shastry Akella1

1University of Alabama at Birmingham, Birmingham, Alabama, USA; 2MediGene, Munich, Germany

An MR diffusion tensor decomposition technique is used to evaluate glioma therapy efficacy in vivo. Five patients each, undergoing “local” and “global” therapies are reported in this study. The approach is shown to permit longitudinal evaluation of therapy, as well as, comparison of two different therapeutic strategies. It is also shown that using the method for segmenting MR images allows in vivo characterization of tumor and surrounding tissue over the longitudinal course of treatment.