Arterial Spin Labeling I
Exhibit Hall 2-3                    Monday 14:00-16:00          Computer 34

14:00         3624.     Assessment of Blood-Brain Water Transfer by Arterial Spin Labeling Based T2 Measurements

Johannes Gregori1, Matthias Günther2, Norbert Schuff3,4

1Radiology & Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA; 2Neurology, University Hospital Mannheim, University of Heidelberg, Heidelberg, Germany; 3Radiology & Biomedical Imaging, University of California San Francsico, CA, USA; 4Center for Imaging of Neurodegenerate Diseases, CIND, VA Medical Center, San Francisco

The assessment of water transfer from vasculature to brain tissue has been difficult with T1 based Arterial Spin Labeling (ASL). In this work, by acquiring multiple echo times in ASL measurements, we demonstrate the feasibility of T2 dependent ASL to assess blood water transfer.

14:30         3625.     Measuring Blood T1 in the Jugular Vein: Juggling Size, Speed and Precision

Qin Qin1, Peter CM. van Zijl1

1Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, USA

Knowledge of blood T1 is important for quantification of CBF using ASL, for setting the inversion time in VASO, and for determining kinetic parameters using dynamic contrast-enhanced MRI. Here, T1 of internal jugular vein at 3T was measured using a fast-inversion-recovery technique in which multiple inversion time points can be acquired rapidly due to constant refreshing of blood. An interesting finding was that of a significant difference (P<0.05) between men, and women, namely T1=1718±62ms (n=6) and T1=1911±55ms (n=6), respectively.

15:00         3626.     Adaptive Sequential Design for Optimal Scheduling of Continuous ASL Data Acquisition

Jingyi Xie1, Peter Jezzard1, Daniel Gallichan1, Roger Gunn2, Stuart Clare1

1FMRIB Centre, Oxford University, Oxford, UK; 2GlaxoSmithKline, Clinical Imaging Centre,, London, UK

In this study we implemented an adaptive sequential design (ASD) variation of an optimal sampling schedule approach to arterial spin labeling data acquisition on a Siemens MR system. This is accomplished by iteratively updating the multi-TI acquisition schedule from a real-time fit to ASL data, based on a D-optimality criterion. Results on normal volunteers showed that the ASD-ASL strategy is capable of giving good parameter estimates on-line, allowing the sampling schedule to be tuned in real-time. Ultimately, we expect this adaptive approach to incorporate pathological/abnormal parameter information and demonstrate the greatest advantage when applied to patient populations.

15:30         3627.     The Influence of Design and Position of the Labeling Coil on the Efficiency in CASL Experiments at 7 T – a Computer Simulation

Robert Trampel1, Mikhail Kozlov1, Thies Jochimsen1, Enrico Reimer1, Toralf Mildner1, Robert Turner1

1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany

Because of the increased signal-to-noise ratio and the prolonged T1 time of arterial blood perfusion measurements at 7 T are expected to be more sensitive. However, especially at such high field strengths the profile of the <B>B</B>1+ field produced by the labeling coil depends strongly on the coil design. This and the position of the coil may influence the efficiency α of the adiabatic spin inversion. A numerical method for predicting α is demonstrated considering the <B>B</B>1+ profile at the position of labeling as simulated using the HFSS software package. A wide range of parameters resulted in sufficient inversion efficiencies.

 
Exhibit Hall 2-3                    Tuesday 13:30-15:30          Computer 34

13:30         3628.     Detection of CBF Changes Due to Activation Over One Month Using ASL Functional MRI

Ajna Borogovac1, Joy Hirsch2, Iris Asllani3

1Biomedical Engineering, Columbia University, New York, NY, USA; 2Neuroscience, Columbia University; 3Radiology, Columbia University

We have shown Arterial Spin Labeling (ASL) perfusion signal to be relatively insensitive to 1/f noise over a period of 4 weeks in group data. This result validates the utility of ASL for longitudinal studies of similar time scales. We have also demonstrated the utility of estimating arterial transit times based of data acquired at multiple labeling durations.

14:00         3629.     Performance of Pseudo-Continuous Arterial Spin Labeling in the Estimation of Fractional Changes in CBF with Activation: Comparison with QUIPSS II

Wen-Ming Luh1, Eric C. Wong2, Peter A. Bandettini1

1FMRIF, NIMH, NIH, Bethesda, MD, USA; 2Departments of Radiology and Psychiatry, University of California, San Diego, La Jolla, CA, USA

Arterial spin labeling (ASL) techniques have been applied to functional studies to estimate cerebral blood flow (CBF) changes during brain activation and in turn to estimate the cerebral metabolic rate of oxygen. Both QUIPSS II and continuous ASL (CASL) with a post-tagging delay are designed to be insensitive to changes in transit delay. In this study, we compare the fractional signal changes with motor activation using UIPSS II, and Pseudo CASL.

14:30         3630.     Arterial Transit Time Effects in Pulsed Arterial Spin Labeling CBF Mapping: Insight from a PET and MR Study of Normal Human Subjects

Maolin Qiu1, Jinghua Wang1, Jagriti Arora1, Yuenan Wang1, Heyonjin Kim1, Nallakkandi Rajeevan1, Beata Planeta-Wilson1, David Weinzimmer1, Richard E. Carson1,2, Robert Todd Constable1,2

1Diagnostic Radiology, Yale University, New Haven, CT, USA; 2Biomedical Engineering, Yale University, New Haven, CT, USA

Arterial transit times (ATT) were estimated using both the perfusion-induced changes in image intensity measured by pulse arterial spin labeling (ASL) and the absolute cerebral blood flow (CBF) quantified by positron emission tomography (PET) on the same group of normal healthy subjects. This work demonstrates the marked dependence of arterial transit times upon the location of the imaging and labeling slabs and quantifies the effect of ATT on measurement of CBF. The results of this study should aid in the interpretation of ASL-based CBF studies, while also providing spatially specific data on ATT values that may aid in optimizing the imaging parameters in ASL acquisitions.

15:00         3631.     Effects of 24hr of Total Sleep Deprivation on Resting CBF Differs in High-Vulnerable and Low-Vulnerable Adults

Hengyi Rao1,2, Julian Lim2, John A. Detre1, Wenchau Wu1, David F. Dinges2

1Center for Functional Neuroimaging, University of Pennsylvania, Philadelphia, PA, USA; 2Unit for Experimental Psychiatry, University of Pennsylvania, Philadelphia, PA, USA

Recent literature has suggested large and reliable inter-individual differences in responses to sleep deprivation. Using ASL perfusion fMRI, the present study examined the effects of 24hr of total sleep deprivation (TSD) on resting cerebral blow flow (CBF) in 20 normal subjects with differential vulnerability. TSD did not alter global CBF, but did induce significant regional CBF changes in multiple brain regions in high-vulnerable subjects and much less change in low-vulnerable subjects. These data suggest that differential effects of sleep deprivation on resting CBF may underlie the trait-like inter-individual differences in sleep deprivation vulnerability.

 
Exhibit Hall 2-3                    Wednesday 13:30-15:30          Computer 34

13:30         3632.     Is Cardiac Gating Necessary in ASL? a Computational and Experimental Study of Flow Dispersion and Cardiac Pulsations

Samira M. Kazan1, Michael A. Chappell2, Stephen J. Payne1

1Institute of Biomedical Engineering, University of Oxford, Oxford, Oxfordshire, UK; 2Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford, Oxford, Oxfordshire, UK

The clinical predictive power of the ASL signal is reduced by significant variability in the signal, which experimental data indicates is affected by dispersion and cardiac pulsatility in blood entering the brain. Our new physiological mass-transport model simulates the transport of the ASL signal from the tagging to imaging bands, coupled with fluid dynamics equations for flow in an elastic vessel. Our simulations indicate that cardiac pulsatility contributes up to 20% of ASL signal variability. This has implications in the choice of single or multiple inversion times, and the use of cardiac gating, in obtaining more accurate measures of CBF.

14:00         3633.     Perfusion and Flow Measurement in Human Brain by Pseudo Random Amplitude Modulation (PRAM) in 3T MRI

Mohammad Reza Taei-Tehrani1,2, Truman R. Brown1,2

1Radiology Department, Columbia University, New York, USA; 2Biomedical Engineering Department, Columbia University, New York, USA

We present here a new method based on pseudo random inversion of inflowing blood. The proposed Pseudo Random Arterial Modulation (PRAM) method uses water as a tracer to measure absolute blood flow and acquires transit times within one integrated scan. The PRAM method does not require separate control and label acquisitions, but rather mixes them according to the specific pseudo random sequence used. PRAM can measure flow distributions, acquiring the range of transit times in the subject. It was tested on phantoms as well as on human subjects with results in agreement with Poiseuille flow calculations.

14:30         3634.     Improved Pseudo-Continuous Arterial Spin Labeling (ASL) for Cerebral Blood Flow Mapping

Marzieh Nezamzadeh1,2, Gerald B. Matson2,3, Karl Young1,2, Michael W. Weiner1,2, Norbert Schuff1,2

1Radiology, University of California San Francisco, San Francisco, CA, USA; 2Center for Imaging of Neurodegenerative Diseases, CIND, VA medical center, San Francisco, san francisco, CA, USA; 3Pharmaceutical Chemistry, University of California San Francisco

Pseudo-continuous arterial spin labeling (pCASL) was previously introduced to overcome the limitations inherent with conventional continuous arterial spin labeling (CASL). However, the control scan (null pulse) in pCASL can be degraded by flow, diminishing the ASL signal. In this study we suggest a new version of pCASL, termed mpCASL, in which the immunity of the null pulse to flow is improved. This is demonstrated by simulations and in-vivo brain perfusion experiments on humans using either CASL, pCASL and the new mpCASL. The experimental findings that perfusion maps using mpCASL show generally better contrast and less blurring than those using CASL or pCASL is consistent with the hypothesis that mpCASL achieves more effective and consistent labeling in presence of variable blood velocity.

15:00         3635.     Quantitative Dynamic MR Angiography Using ASL Based TrueFISP

Lirong Yan1, Yan Zhuo1, Jiongjiong Wang2

1State Key Lab of Brain & Cognition, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; 2Radiology, University of Pennsylvania, Philadelphia, PA, USA

Contrast-enhanced dynamic MR angiography (CE-dMRA) has received considerable attention recently. Its temporal resolution, however, is generally on the order of seconds and the method requires intravenous injection of contrast agent. We propose a novel method for noninvasive 4D dynamic MRA by marrying ASL with a multi-phase TrueFISP readout. Interleaved inversion recovery TrueFISP acquisitions were carried out following slice-selective or non-selective inversion pulses. We show high quality dynamic MRA of the Circle of Willis with millimeter spatial resolution and millisecond temporal resolution. A theoretical model has been proposed for quantification of blood flow within blood vessels.

 
Exhibit Hall 2-3                    Thursday 13:30-15:30          Computer 34

13:30         3636.     Baseline CBF Correlation with Individual Alpha Peak Frequency

Kay Jann1, Thomas Koenig1, Chris Boesch2, Thomas Dierks1, Andrea Federspiel1

1Dept. of Psychiatric Neurophysiology, University Hospital of Psychiatry, Bern, Switzerland; 2AMSM, University Hospital / Inselspital, Bern, Switzerland

In this explorative study we focussed on the relationship between baseline CBF and individual alpha frequency (IAF) calculated from EEG data in a cohort of 10 healthy subjects. Since the IAF is a parameter for the frequency of EEG oscillations it can be used as a measure of a subject’s vigilance level. Accordingly, we wondered whether correlations between IAF and baseline CBF can be found in primary sensory regions (representing the preparedness for external input) or in brain areas involved in vigilance control.

14:00         3637.     Investigating Transcranial Magnetic Stimulation (TMS) Effects Using Pulsed Arterial Spin Labeling (PASL)

Andrea Federspiel1, Ariane Orosz1, Kay Jann1, Matthias Grieder1, Miranka Wirth1, Roland Wiest2, Thomas Dierks1

1Dept. of Psychiatric Neurophysiology, University Hospital of Psychiatry, Bern, Switzerland; 2Dept. of Neuroradiology, University Hospital/Inselspital, Bern, Switzerland

Here we investigate transcranial magnetic stimulation (TMS) effects using Pulsed Arterial Spin Labeling (PASL) on healthy subjects. We addressed the question of whether an effect of TMS is detectable with ASL in subject performing a task. We aimed to explore putative TMS effects on CBF measure. We observe a reduction of CBF measure post TMS as compared to pre TMS condition only in brain regions that were subject to TMS stimulation including its homologue contralateral, not stimulated side. Although the small sample size, our data demonstrate the feasibility of detecting TMS effects using ASL.

14:30         3638.     Cerebral Perfusion in Craniosynostotic Rabbits Using ASL_MRI

Lesley M. Foley1, Wendy Fellows-Mayle2, T Kevin Hitchens1,3, Joseph E. Losee4,5, M I. Siegel6, M P. Mooney6, Chien Ho1,3

1Pittsburgh NMR Center for Biomedical Research, Carnegie Mellon University, Pittsburgh, PA, USA; 2Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; 3Department of Biological Science, Carnegie Mellon University, Pittsburgh , PA, USA; 4Division of Pediatric Plastic Surgery, Children's Hospital of Pittsburgh, Pittsburgh, PA, USA; 5Pittsburgh Cleft-Craniofacial Center, Children's Hospital of Pittsburgh, Pittsburgh , PA, USA; 6Department of Anthropology, University of Pittsburgh, Pittsburgh, PA, USA

Craniosynostosis occurs in 400 per 1,000,000 live births and is associated with elevated intracranial pressure (ICP). Elevated ICP in craniosynostosis has, in turn, been associated with changes in ventricle volume and cerebral blood flow (CBF). Remarkably early-onset cranial synostotic (EOCS) rabbits at 25 days of age displayed areas of high CBF on the peridural surfaces of the brain, which coincides with a period of increased ICP. By 42 days of age, CBF in the pial vasculature no longer demonstrated high CBF in EOCS rabbits which follows a lowering of ICP at this age.

15:00         3639.     Colloid Based Resuscitation Following Asphyxial Cardiac Arrest: ASL_MRI Assessment of Regional Cerebral Blood Flow.

Lesley M. Foley1, Mioara D. Manole2, T Kevin Hitchens1,3, Patrick M. Kochanek4,5, Robert W. Hickey2, Henry L. Alexander4, Hulya Bayir2,6, Chien Ho1,3, Robert S. Clark2,7

1Pittsburgh NMR Center for Biomedical Research, Carnegie Mellon University, Pittsburgh, PA, USA; 2Department of Pediatrics, Children's Hospital of Pittsburgh, Pittsburgh, PA, USA; 3Department of Biological Science, Carnegie Mellon University, Pittsburgh , PA, USA; 4Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA, USA; 5Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh , PA, USA; 6Department of Critical Care Medicine, University of Pittsburgh  , Pittsburgh , PA, USA; 7Department of Critical Care Medicine, University of Pittsburgh , Pittsburgh, PA, USA

Colloids such as albumin and polynitroxyl albumin (PNA), a highly nitroxylated antioxidant form of albumin, resulted in improved CBF in models of focal ischemia. The effect of resuscitation with colloid on CBF after CA remains to be defined. PNA given at resuscitation from CA decreased the initial hyperemia, while albumin produced a more prolonged and intense hyperemic response in all brain regions. The mechanisms responsible for these CBF changes and the effects of albumin and PNA given at resuscitation on neurological outcome remain to be determined.

 


 
Arterial Spin Labeling II
Exhibit Hall 2-3                    Monday 13:30-14:00          Computer 35

14:00         3640.     Characterization of Vascular Territory Changes Following Carotid Artery Compression Using Arterial Spin Labeling MRI

Akash Pravin Kansagra1, Eric Che Wong2

1School of Medicine, University of California, San Diego, La Jolla, CA, USA; 2Radiology and Psychiatry, University of California, San Diego, La Jolla, CA, USA

Vessel encoded pseudo-continuous ASL allows quantitative characterization of vascular supply to the human brain. In this work, we discuss the application of vessel encoded pseudo-continuous ASL to resolve perfusion changes that occur in response to manual compression of the common carotid artery in healthy human subjects. These data may provide insight into the development of collateral routes of circulation following acute alterations in blood flow.

14:30         3641.     Can Arterial Spin Labeling Be Used to Identify Perfusion Distribution Differences Using Group Analysis?

Dennis Armand Kies1, Julien R. Milles2, Wouter M. Teeuwisse1,3, Johan R.C. Reiber2, Andrew Webb1,3, Mark A. Van Buchem1,3, Matthias J.P. Van Osch1,3

1Radiology, Leiden University Medical Center, Leiden, Netherlands; 2LKEB, Leiden University Medical Center, Leiden, Netherlands; 3C.J. Gorter Center for High Field MRI, Leiden, Netherlands

Arterial spin labeling provides a completely non-invasive tool for quantitative measurement of CBF and can therefore easily be added to clinical research protocols. Most frequently a voxel-based morphometry-like analysis method is employed to identify differences in the perfusion distribution between a patient and control group. How well such a procedure is able to detect differences in perfusion patterns is unknown. This is evaluated by using neuronal activation to achieve CBF changes. This yields a gold standard (rest minus activation per subject) as well as the outcome of a group analysis (rest scans of group A versus activation of group B).

15:00         3642.     Estimation of Pure Gray Matter Perfusion Using Pseudo-Continuous Arterial Spin Labeling and Partial Volume Correction

Wen-Ming Luh1, Peter A. Bandettini1

1FMRIF, NIMH, NIH, Bethesda, MD, USA

With typical spatial resolution used in MR perfusion imaging, the number of 100% GM voxels is very small with folding cortical layers of about 2-4mm thick. Therefore it is important to take partial volume effects (PVE) into account for quantifying measured cerebral blood flow in the human brain as well as for comparison to animal models with little PVE. Here a strategy is proposed to correct for PVE with arterial spin labeling (ASL) measurements using pseudo-continuous ASL.

15:30         3643.     Pseudo-Continuous Artery-Selective Spin Labeling (Pseudo-CASSL)

Michael Helle1, Matthias van Osch2, David G. Norris3, Susanne Rüfer1, Karsten Alfke1, Olav Jansen1

1Institute of Neuroradiology, University Hospital of Schleswig-Holstein, Kiel, Germany; 2Leiden University Medical Center, Leiden, Netherlands; 3Donders Institute for Brain, Cognition and Behaviour, Nijmegen, Netherlands

A modified tagging scheme is proposed that combines the pseudo-continuous labeling mechanism with a rotating labeling plane to achieve selective labeling of single vessels. By employing additional gradients during the application of the RF pulses, the influence of the labeling is made local, circumventing phase effects further away from the targeted vessel and the associated risk of unwanted labeling distal to the selected artery. An increase in the tilting angle between selected artery and labeling plane results in an increased selectivity, which makes this technique capable of selectively labeling cerebral arteries.

 
Exhibit Hall 2-3                    Tuesday 13:30-14:00          Computer 35

13:30         3644.     Cerebral Blood Flow and Transit Time Measured by Quantitative Arterial Spin Labeling: Comparison with 15O-PET

Hironori Kamano1, Takashi Yoshiura1, Akio Hiwatashi1, Koji Yamashita1, Eiki Nagao1, Yukihisa Takayama1, Tomoyuki Noguchi1, Koichiro Abe1, Koichiro Kaneko1, Ivan Zimine2, Tomoyuki Okuaki2, Hiroshi Honda1

1Department of Clinical Radiology, Kyushu University, Fukuoka, Japan; 2Philips Electronics Japan, Japan

We compared CBF and arterial transit time (ATT) measured by ASL with CBF and mean transit time (MTT) measured by 15O-PET in 13 patients with cerebral arterial steno-occlusive diseases. Region-of-interest analysis of the parametric maps revealed a significant correlation between CBF values by ASL and those by PET. Comparison of ATT by ASL and MTT by PET revealed no significant correlation, while left-to-right ratio (L/R) of ATT in posterior watershed area significantly correlated with L/R of MCA CBF and L/R of MCA MTT by PET. ATT by ASL may convey clinically useful information regarding regional hemodynamic status.

14:00         3645.     Arterial Spin Label CBF Maps Can Show Abnormalities in Clinical Patients with Normal Bolus Perfusion-Weighted Imaging:  Identification of the "Watershed Sign"

Greg Zaharchuk1, Ajit Shankaranarayan2, Roland Bammer1, Matus Straka1, David C. Alsop3, Nancy J. Fischbein4, Scott W. Atlas4, Michael E. Moseley1

1Department of Radiology, Stanford University, Stanford, CA, USA; 2Appled Sciences Laboratory - West, GE Healthcare, Menlo Park, CA, USA; 3Department of Radiology, Beth Israel Deaconess Hospital, Boston, MA, USA; 4Department of Radiology, Stanford University Medical Center, Stanford, CA, USA

ASL imaging is very sensitive to arterial arrival times and can detect abnormalities in patients with normal bolus PWI studies, the most common of which we have termed the watershed sign.

14:30         3646.     Assessment of Cerebral Perfusion MRI Using Arterial Spin Labeling and Dynamic Susceptibility Contrast in Individuals with Carotid Artery Disease

Bradley J. MacIntosh1, Ediri Sideso2, Manus J. Donahue1, Atle Bjørnerud3, Matthias Günther4, Ashok Handa5, James Kennedy2, Peter Jezzard1

1Clinical Neurology, FMRIB Centre, Oxford, Oxfordshire, UK; 2Acute Stroke Programme, Nuffield Department of Clinical Medicine, John Radcliffe, Oxford, Oxfordshire, UK; 3Medical Physics, Rikshospitalet University Hospital, Oslo, Norway; 4Neurology, University hospital Mannheim, University of Heidelberg, Heidelberg, Germany; 5Nuffield Department of Surgery, John Radcliffe, Oxford, Oxfordshire, UK

Dynamic susceptibility contrast (DSC) is the industry-standard perfusion MRI technique. It has been used extensively to characterise the effects of ischaemia in stroke patients. DSC is not suitable for all patients, however, and although rare the contrast agent is associated with potential side effects. Arterial spin labeling (ASL) is non-invasive and may be a useful alternative perfusion MRI technique. In the current study we compare CBF maps from DSC and ASL directly and find a good correlation (R = 0.27 ± 0.094, P < 0.01) between CBF maps in a group of 10 patients with carotid artery disease.

15:00         3647.     Cerebral Blood Flow and Arterial Transit Time Measurements in Patients with Chronic Occlusive Cerebrovascular Disease Using 3D Spiral SE Arterial Spin Labeling on 3T-MR: Correlative Study with O15 Labeled H2O PET Examination.

Hirohiko Kimura1, Hidehiko Okazawa2, Tsuyoshi Matsuda3, Yoshikazu Arai4, Asit Shankaranarayanan5, David Alsop6

1Radiology, University of Fukui, Eiheiji, Fukui, Japan; 2Biomedical Imaging Center, University of Fukui, Eiheiji, Fukui, Japan; 3GE-YMS, Hino, Tokyo, Japan; 4Neurosurgery, University of Fukui, Eiheiji, Japan; 5GE Helthcare, USA; 6Radiology, Beth Israel Deacones Medical center, Boston, MA, USA

Arterial spin labeling (ASL) is a means of non-invasive MR perfusion assessment that provides a quantitative map of cerebral blood flow. However, it has not been investigated whether the hemodynamic changes in patients with occlusive cerebrovascular disease which affect the utility of ASL. The goal of the current study is to demonstrate arterial transit map calculation as well as CBF based on a two-compartment model using a 3D spiral SE sequence. The comparison of CASL-CBF and O15 labeled H2O PET-CBF was also performed for the validation of delay compensated CBF values in patients with chronic occlusive cerebrovascular disease.

 
Exhibit Hall 2-3                    Wednesday 13:30-14:00          Computer 35

13:30         3648.     LL-FAIR: Implementation and Application at 7T

Susan T. Francis1, Roman Wesolowski1, Emma L. Hall1, Penny A. Gowland1

1School of Physics and Astronomy, University of Nottingham, Sir Peter Mansfield Magnetic Resonance Centre, Nottingham, Nottinghamshire, UK

The feasibility of LL-FAIR, also known as ITSFAIR or QUASAR, at 7T is demonstrated. LL-FAIR is implemented using optimised readout pulse timing and flip angles to suppress the static tissue signal, thus providing inherent background suppression to reduce physiological noise. Increased signal-to-noise ratio (SNR) and relaxation times at 7T result in increased sensitivity. Arterial Cerebral Blood Volume (CBVa) and Cerebral Blood Flow (CBF) data are collected at high spatial resolution, with improved Mbo estimation due to reduced partial volume effects. Functional CBF and CBVa maps show improved spatial localisation and reduced physiological noise compared to BOLD, with the possibility of mapping changes to a single activation cycle.

14:00         3649.     Accurate Gray Matter CBF Mapping in Whole Brain IR 3D PULSAR Imaging Through Flip Angle Modulation

Neville Dali Gai1, Sardha Lalith Talagala2, John Butman1

1Radiology & Imaging Sciences, National Institutes of Health, Bethesda, MD, USA; 2NINDS, National Institutes of Health, Bethesda, MD, USA

3D IR-PULSAR provides whole brain perfusion imaging in about 5 minutes. Data acquisition is through use of centric-ordered slice encoding (along kz) followed by single-shot gradient-echo EPI acquisition. In addition to tagged blood signal decay during extended data acquisition, modulation of k-space during non-steady state constant flip angle acquisition results in blurring. This introduces inaccuracies in gray matter and white matter perfusion values. Here we correct for blurring by modulating the flip angle train so that magnetization in gray matter remains almost constant across all 3D-TFEPI shots. Optimization for tagged blood signal is used to select the modulated pulse angle train. Results in five volunteers show significantly increased gray matter CBF values due to a marked reduction in blurring.

14:30         3650.     What Is the Detectability of Arterial Transit Times in Pulsed Arterial Spin Labeling (PASL): A Simulation and Empirical Study

Bradley J. MacIntosh1, Nicola Filippini1, Manus J. Donahue1, Michael A. Chappell1, Clare E. Mackay1, Peter Jezzard1

1Clinical Neurology, FMRIB Centre, Oxford, Oxfordshire, UK

Arterial spin labeling (ASL) is a versatile perfusion MRI technique. It has long been known however that CBF estimates are highly sensitive to the arterial transit time. In the current study we investigate the detectability of ATT and assess the value of mapping ATT across the brain as a complementary imaging metric to CBF. Simulations were also performed at 3 T to determine the detectability of CBF and ATT over a range of simulated transit times and SNR conditions. ATT maps were found to be reliable over a range of physiological scenarios. ATT varied across the brain according to the vascular territories. Sex differences were also highly significant, with women having a shorter ATT compare to men.

15:00         3651.     CSF-Suppression Improves Signal Stability of ASL Time Series

Yufen Chen1, David Minkoff1, Jiongjiong Wang1, John A. Detre1

1Center of Functional Neuroimaging, University of Pennsylvania, Philadelphia, PA, USA

ASL-fMRI times series are typically acquired using EPI, which are heavily T2* weighted. The high signal of CSF and partial volume effects between CSF and gray matter lead to large signal fluctuations which affect the sensitivity for detection of functional activation. For this study, a selective inversion pulse was used to suppress CSF signal in a pseudo-continuous ASL time series. CSF-suppression reduced time series standard deviation by 33% (p=0.022) compared to the unsuppressed time series. The improved stability afforded by CSF-suppressed ASL is beneficial for ASL-fMRI.

 
Exhibit Hall 2-3                    Thursday 13:30-14:00          Computer 35

13:30         3652.     Automated Segmentation of Multiple Vascular Territories from Vessel Encoded Pseudo-Continuous Arterial Spin Labeling MRI Data

Akash Pravin Kansagra1, Eric Che Wong2

1School of Medicine, University of California, San Diego, La Jolla, CA, USA; 2Radiology and Psychiatry, University of California, San Diego, La Jolla, CA, USA

Vessel encoded pseudo-continuous ASL allows assessment of vascular territories in the human brain. Here, we discuss a novel region-growing algorithm which allows automated segmentation of perfusion data into multiple vascular territories with minimal scan time. This technique may prove particularly useful in defining vascular territories above the circle of Willis that are not easily amenable to Hadamard-type encoding.

14:00         3653.     Utility of Shared Rotating Control Acquisition for Territorial ASL

Ivan Zimine1, Takashi Yoshiura2, Akio Hiwatashi2, Tomoyuki Noguchi2, Marc Van Cauteren1

1Clinical science, Philips Healthcare, Minato-ku, Tokyo, Japan; 2Departments of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Japan

Territorial ASL is a very interesting application for evaluation of patients with various cerebro-vascular disorders. Motion, however, is a serious issue, because its effects can not be easily corrected by post-processing. Reduction of scan time is an obvious strategy to reduce sensitivity to motion. Here we evaluate the use of shared rotating control for subtraction from multiple labeling conditions. Despite visible effects due to imperfect MT cancellation at early inversion times, this approach is useful for depiction of vascular territories.

14:30         3654.     Theoretical Investigation and Optimization of the Labeling Process in Continuous Artery-Selective Spin Labeling (CASSL)

Michael Helle1, David G. Norris2, Susanne Rüfer1, Karsten Alfke1, Olav Jansen1

1Institute of Neuroradiology, University Hospital of Schleswig-Holstein, Kiel, Germany; 2Donders Institute for Brain, Cognition and Behaviour, Nijmegen, Netherlands

Continuous artery-selective spin labeling (CASSL) is one technique to image perfusion territories of single cerebral arteries.

15:00         3655.     2D RF Versus Slice Selective RF Tagging Pulses in Brain ASL

Simon Konstandin1, Patrick Michael Heiler1, Lothar Rudi Schad1

1Computer Assisted Clinical Medicine, University of Heidelberg, Mannheim, Germany

Standard perfusion ASL methods use inversion pulses in a transversal slice to determine the cerebral perfusion territories of all major blood vessels. In this work, we implemented a two-dimensional selective inversion pulse to tag either the left or the right internal carotid artery (ICA). Alternatively, a sagittal slice selective inversion pulse along the ICA was used to tag the inflowing blood. Resulting ASL images and relative perfusion signals were compared to determine the optimal measurement technique. The method using the sagittal labeling slice delivers higher perfusion values. But the technique using the 2D RF pulse is more selective.

 


 
fMRI Acquisition Methods
Exhibit Hall 2-3                    Monday 14:00-16:00          Computer 36

14:00         3656.     Fast Measurement of Arteriovenous Oxygenation Differences Using Blood T2 in the Jugular Vein and Carotid Artery at 3T

Qin Qin1,2, Peter C.M. van Zijl1,2

1Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, USA; 2F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA

Oxygen Extraction Fraction (OEF) is an important clinical parameter that can be derived from the difference in arterial and venous oxygenation. We developed a pulse sequence that utilizes both non-selective T2 preparation and slice-selective saturation to simultaneously measure blood T2 in the internal jugular vein and internal carotid artery. Using a calibration curve from a separate blood phantom, these T2s were related to oxygenation (Y) and the arteriovenous differences (Ya-Yv) determined. The resulting oxygenations (n = 5) were Ya =1±0 and Yv=0.71±0.03, leading to OEF=0.29±0.03, in agreement with the literature.

14:30         3657.     Investigation Into the Benefits of 3D-EPI for High-Resolution FMRI at 7T

Benedikt Andreas Poser1,2, Peter J. Koopmans2, Lawrence L. Wald3, Markus Barth1,2

1Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany; 2Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, Netherlands; 3Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, USA

A 3D-EPI sequence was implemented and its use investigated for high-resolution fMRI at 7T. Comparisons with conventional 2D-EPI reveal considerably increased sensitivity for isotropic 2.5mm resolutions and higher. Results of a whole-brain activation study at 1mm3 resolution at TR=3s are presented. The ability to apply parallel acceleration along two dimensions allows substantial time savings and protocols with >100 slices to remain compatible with fast fMRI. The SAR and gradient limitations or 2D-EPI are removed entirely, and the often compromised parallel reconstruction of 2D-EPI in regions of low SNR considerably improved. The results strongly suggest that 3D-EPI should be chosen over 2D at high field.

15:00         3658.     Frequency-Dependent Cerebral Blood Flow-Volume Coupling in Activated Human Visual Cortex

Ai-Ling Lin1, Peter T. Fox1

1Research Imaging Center, University of Texas Health Science Center, San Antonio, TX, USA

Neuronal activations elicit responses in cerebral blood flow (CBF) and volume (CBV). However, whether the flow-volume coupling persists unchanged or varies with brain activities in humans during brain functions remains unclear. In the study, relative CBF and CBV were measured with arterial spin labeling (ASL) and Gd-DTPA contrast agent, respectively, during visual stimulation at 4 and 8 Hz. The result shows that the flow-volume coupling (α value) is not constant, but stimulus frequency-dependent. The frequency-varying flow-volume coupling would facilitate our future understanding of BOLD mechanism and the determination of cerebral metabolic rate of oxygen metabolism (CMRO2).

15:30         3659.     Feasibility of QUantitative Imaging of EXtraction of Oxygen and TIssue Consumption (QUIXOTIC) to Assess Functional Changes in Venous Oxygen Saturation During Visual Stimulus

Divya S. Bolar1,2, A Gregory Sorensen1, Bruce R. Rosen1, Elfar Adalsteinsson1,2

1A.A. Martinos Center for Biomedical Imaging, HST/MGH/HMS/MIT, Charlestown, MA, USA; 2Electrical Engineering & Computer Science, MIT, Cambridge, MA, USA

Recent studies suggest that an fMRI technique able to directly evaluate functional changes in absolute venous oxygen saturation may be a more repeatable and physiologically relevant way to assess neuronal activation. A newly developed fMRI technique called QUantitative Imaging of eXtraction of Oxygen and TIssue Consumption (QUIXOTIC) allows direct measurement of venous oxygen saturation, by exclusively targeting signal from venular blood localized to sites of neuronal activity. In this study, we assess the feasibility of using QUIXOTIC to quantitatively measure functional changes in local venous oxygen saturation in response to a visual stimulus.

 
Exhibit Hall 2-3                    Tuesday 13:30-15:30          Computer 36

13:30         3660.     Mapping the Cerebral Blood Volume Response to Cocaine with Pharmacological MRI in Mice at 7 T

Adriana Teodora Perles-Barbacaru1, Daniel Procissi1, Andrey Valentinovich Demyanenko1, Russell E. Jacobs1

1Caltech Brain Imaging Center, California Institute of Technology, Pasadena, CA, USA

This study investigated the region specific cerebral blood volume (CBV) changes in response to cocaine administration in spontaneously breathing, isoflurane-anesthetized mice using a steady state T2* weighted MRI technique at 7 T with MION as a blood pool contrast agent. A consistent CBV decrease was observed, which lasted for up to 60 minutes after intraperitoneal cocaine injection. Vasodilatation with intraperitoneal Acetazolamide was used to validate the technique and resulted in a CBV increase of shorter duration. We demonstrated the sensitivity and reproducibility of this technique for mapping the cerebrovascular reactivity to cocaine in mice at 7 T.

14:00         3661.     T1 Sensitive Images with the Aid of New Blood-Pool Contrast Agent in Mapping Cortical Centers in Neurosurgical Patients

Agata Majos1, Tomasz Wolak2, Piotr Bogorodzki3, Krzysztof Tybor4, Mariusz Heleniak4, Ludomir Stefañczyk5

1Radiology, Medical University of Lodz, Lodz, Poland; 2Institute of Physiology and Pathology of Hearing, Warsaw, Poland; 3Institute of Radioelectronics, Warsaw University of Technology, Warsaw, Poland; 4Neurosurgery, Medical University of Lodz, Lodz, Poland; 5Radiology, Medical Univerity of Lodz, Lodz, Poland

The aim - to determine the possibility to use T1 sequence with the administration of blood pool contrast agent (BPCA) in patients with brain tumors before and after operation.

14:30         3662.     Stability of Alternating BSSFP Signal in the Presence of Driving Perturbations

Giedrius T. Buracas1, Youngkyoo Jung1, Eric C. Wong1,2, Richard B. Buxton1, Thomas T. Liu1

1Radiology, UCSD, La Jolla, CA, USA; 2Psychiatry, UCSD, La Jolla, CA, USA

It has been proposed recently that MRI can be used to detect currents generated during neuronal activity in the brain. We have demonstrated that an MRI imaging method based on alternating balanced steady states (ABSS) is more sensitive to weak magnetic fields than traditional GRE or SE methods. Herein we have explored the impact of the high neuronal-like variability of the driving signal on the ABSS signal. Our results suggest that the ABSS signal exhibits a high degree of stability and only moderate signal reduction in the presence of strong perturbations akin to those found in cerebral cortical responses.

15:00         3663.     Motion-Compensated Interleaved Spiral Acquisition for FMRI

Heiko Schmiedeskamp1, Murat Aksoy1, Gary H. Glover1, Roland Bammer1

1Lucas Center, Department of Radiology, Stanford University, Stanford, CA, USA

We propose combining a low-resolution spiral-in navigator trajectory with the acquisition of a higher-resolution interleaved spiral-out readout trajectory for motion-compensated multi-shot fMRI. Therefore, the navigator trajectory is used for two purposes: 1) for in-plane motion correction and realignment of multi-shot data, 2) for separate low-resolution fMRI analysis in order to extend functional analysis by a low-resolution dataset. Thus, the presented method facilitates high-resolution motion-corrected interleaved spiral-acquisition with additional low-resolution images to either mask high resolution data or to compare BOLD-activation acquired with two different image resolutions.

 
Exhibit Hall 2-3                    Wednesday 13:30-15:30          Computer 36

13:30         3664.     Best Practice EEG-MRI: The Utility of Retrospective Synchronization and PCA for the Removal of Gradient Artefacts.

Hendrik Mandelkow1, Daniel Brandeis2, Peter Boesiger1

1Inst. for Biomedical Engineering, ETH Zurich, Zurich, Switzerland; 22)  Dept. of Child and Adolescent Psychiatry, University of Zurich, Zurich, Switzerland

We present a new software synchronization method for removing the notorious MRI gradient artefact (MGA) from EEG data recorded during MRI. Furthermore, we propose new methods for quantifying and comparing the performance of different post-processing algorithms for EEG-fMRI data. Comparisons based on in-vivo data as well as simulations of the MGA show that the retrospective synchronisation algorithm can substitute hardware synchronisation as well as other post-processing methods such as slice timing correction and PCA. This insight points toward an optimal recording and post-processing strategy for EEG-fMRI experiments.

14:00         3665.     Characterising Gradient Artefacts in Simultaneous EEG/fMRI Through Physical Modelling

Winston X. Yan1, Karen J. Mullinger1, Matthew J. Brookes1, Richard W. Bowtell1

1Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, Nottinghamshire, UK

Temporally varying magnetic field gradients generate large artefacts in EEG recordings during simultaneous EEG/fMRI. Using physical modelling, we study the gradient artefacts across two different modes: analytic expressions assuming simplified wirepaths, and numerical simulation using the actual wiring patterns of the EEG cap. Strong correlation was observed between the spatial artefact maps of our simulations and experimental measurements on both a spherical agar phantom and human head. The accuracy of the modelling and its versatility in accounting for any head orientation should facilitate the development of improved artefact correction algorithms incorporating motion tracking and calculated spatial artefact templates.

14:30         3666.     Silent High Resolution Echo-Planar Imaging for Auditory FMRI

Jascha Zapp1, Sebastian Schmitter2, Lothar R. Schad1

1Computer Assisted Clinical Medicine, Faculty of Medicine Mannheim, University of Heidelberg, Mannheim, Germany; 2Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany

In fMRI, acoustic scanner noise causes an unwanted BOLD signal in the auditory cortex. High resolution imaging using EPI with PAT produces high sound pressure level (SPL) due to fast switching of trapezoidal gradients.

15:00         3667.     Silent Sparse Sampling for Auditory FMRI

Todd Parrish1, Vibhas Deshpande2, Yu Fen Chen3

1Radiology, Northwestern University, Chicago, IL, USA; 2Siemens Medical Solutions; 3University of Pennsylvania

The goal of this study is to develop a truly silent sparse sampling method for auditory fMRI. By using a constant gradient during the silent period and playing the RF at the appropriate timing, the steady sate magnetization is maintained. Then a standard EPI module is played to capture the BOLD signal response. A burst sparse sampling is applied to make the sparse sampling more efficient. This will improve auditory fMRI investigations or simplified clinical applications without the need for a visual presentation.

 
Exhibit Hall 2-3                    Thursday 13:30-15:30          Computer 36

13:30         3668.     A Novel T2* GRASE Single-Shot 3D Sequence for BOLD Imaging

David A. Feinberg1,2, Sudhir Ramanna1

1Advanced MRI Technologies, Sebastopol, CA, USA; 2Helen Wills Neuroscience Institute, University California Berkeley, Berkeley, CA, USA

A novel k-space trajectory in 3D GRASE has achieved T2* weighted contrast without requiring preparation pulses, or violation of the CPMG condition by means of shifting the order of phase encoding so that ko and central k-space does not fall upon spin echoes. The technique has achieved single-shot 3D GRASE images with T2* and BOLD contrast as evaluated at 1.5T and 3T imaging with a motor task paradigm.

14:00         3669.     First Demonstration of SS-PARSE in Detecting the BOLD Effect in Humans

Edward Walsh1,2, Donald Twieg3, Michael Worden1,2, Stanley Reeves4, Jerome Sanes1,2

1Department of Neuroscience, Brown University, Providence, RI, USA; 2Institute for Brain Science, Brown University, Providence, RI, USA; 3Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL, USA; 4Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, USA

The SS-PARSE (Single-Shot Parameter Assessment by Retrieval from Signal Encoding) technique addresses difficulties relating to conventional MR reconstruction methodology by modeling raw data as evolving in time (k,t-space). Using a nonlinear optimization process to provide an inverse solution to the MR signal equation, the SS-PARSE reconstruction produces parametric maps of magnetization, R2*, and frequency from a single-shot signal. In this report, the first demonstration of BOLD activation detection in humans using SS-PARSE is presented.

14:30         3670.     MR-Encephalography: Fast Volumetric Imaging of Brain Physiology Using Rosette Trajectories

Benjamin Zahneisen1, Thimo Grotz1, Juergen Hennig1

1Dept. of Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany

MR-Encephalography (MREG) is an extremely fast technique to monitor physiological changes in the brain by use of simultaneous readout with multiple RF-coils. Recently a radial sampling scheme (COBRA) with very low number of projections was proposed in order to improve localization of activation at the cost of temporal resolution.

15:00         3671.     Pushing the Limits: Ultrafast 2D Accelerated High Resolution Whole-Head Volumetric Functional Imaging at 7 Tesla

Tram Nguyen1, Steen Moeller2, Ute Goerke2, Essa Yacoub2, Kamil Ugurbil2

1High-Field Magnetic Resonance Center, Max-Planck Institute for Biological Cybernetics, Tübingen, Germany; 2Center for Magnetic Resonance Research, Minneapolis, MN, USA

In the tendency towards high-field imaging, three-dimensional (3D) acquisition has potential advantages over its two-dimensional counterpart for functional MRI (fMRI). However, multi-slice 2D-EPI methods remain the conventional sequence in fMRI. Although various advanced 3D schemes have alternatively been applied, they come with individual limitations and are not widely available. The 3D-EPI sequence similarly presents temporal constraints, but holds the potential to be feasible by using the increased signal- and contrast-to-noise ratio of ultrahigh magnetic fields combined with the higher parallel imaging performance feasible at ultra-high fields. A hybrid 3D-EPI then offers the possibility for high 2D acceleration. This potential is exploited in this study at 7 Tesla to overcome the limitations and compare results with 2D acquisition and 1D acceleration. Results show the feasibility of a highly accelerated hybrid 3D-EPI scheme for high resolution whole-head acquisition in high-field fMRI, presenting excellent functional results.

 


 
fMRI Analysis
Exhibit Hall 2-3                    Monday 14:00-16:00          Computer 37

14:00         3672.     Comparison Between End-Tidal CO2 and Tidal Volume Changes Calculated from the Respiratory Motion Tracing Used for Correction of Respiratory Fluctuations in a Functional MRI Experiment with Normal Breathing and Hyperventilation

Keith Michael Vogt1, James W. Ibinson2, Robert H. Small1, Petra Schmalbrock3

1Anesthesiology, The Ohio State University, Columbus, OH, USA; 2Anesthesiology, University of Pittsburgh Medical Center, Pittsburgh, PA, USA; 3Radiology, The Ohio State University, Columbus, OH, USA

Functional MRI data was acquired during normal ventilation and paced hyperventilation that caused a 35% decrease in end-tidal CO2 (ETCO2). Respiratory motion and expired CO2 data were collected and respiratory volume over time (RVT) and ETCO2 values were calculated. Although negatively correlated, the RVT and ETCO2 timecourses did not strictly mirror each other. RVT and ETCO2 values were convolved with appropriate response functions and regressed against each voxel timecourse. The ETCO2 regressor was more strongly and diffusely correlated to the FMRI data, suggesting that ETCO2 monitoring may be warranted in studies with large changes in respiration.

14:30         3673.     Activity-Based Seed Regions for Resting-State FMRI Analysis Are Susceptible to Large Vessels

Ali Mohammad Golestani1, Bradley Goodyear2

1Electrical & Computer Engineering, University of Calgary, Calgary, Alberta, Canada; 2Radiology & Clinical Neuroscience, University of Calgary, Calgary, Alberta, Canada

Because task-related BOLD fMRI is susceptible to large vessels, the objective of this study was to compare the location of seed regions for resting-state connectivity analysis based on task-related maps to those based on an anatomical approach. Overlap between the two methods was not considerable, suggesting that task-based and anatomical-based seeds do not converge upon the same region. Task-based seeds were located at more superior locations in the brain in proximity to large draining vessels, as compared to anatomy-based seeds. Hence, seed regions based on brain activity in response to tasks may not be optimal for analysis of resting-state networks.

15:00         3674.     Stockwell Coherence Measures Resting-State Connectivity with Low Between-Session Variability

Ali Mohammad Golestani1, Bradley Goodyear2

1Electrical & Computer Engineering, University of Calgary, Calgary, Alberta, Canada; 2Radiology & Clinical Neuroscience, University of Calgary, Calgary, Alberta, Canada

In this study we introduce a time-frequency approach based on the Stockwell transform to quantify resting-state connectivity and compare its reproducibility to cross-correlation and coherence. Our results show that Stockwell coherence is not susceptible to changes in TR and scan duration and does not differ between sessions, whereas cross-correlation and coherence exhibit dependencies on TR and scan duration, respectively. Stockwell coherence also exhibits a significantly lower coefficient of variation across imaging sessions. Hence, Stockwell coherence is a potentially useful tool for resting-state connectivity analysis, even in the presence of intermittent disruptions of the resting state.

15:30         3675.     Functional Network Connectivity with Temporal Derivatives of SICA Time-Courses in Schizophrenia Patients Vs Healthy Controls

Unal Sakoglu1, Vince D. Calhoun1

1The Mind Research Network, Albuquerque, NM, USA

In this work, a correlation approach that uses temporal derivatives of associated time-courses of spatially independent brain networks was developed and it was applied to assess functional network connectivity differences between chronic schizophrenia patients and healthy controls. The results were compared with an existing maximal lagged-correlation method.

 
Exhibit Hall 2-3                    Tuesday 13:30-15:30          Computer 37

13:30         3676.     Dynamic Windowing Reveals Task-Modulation of Functional Connectivity in Schizophrenia Patients Vs Healthy Controls

Unal Sakoglu1, Vince D. Calhoun1

1The Mind Research Network, Albuquerque, NM, USA

In this work, a dynamic time-window analysis approach was developed to assess functional network connectivity during change from no-task to task condition and vice versa. The approach was applied to fMRI data from chronic schizophrenia patients and matched healthy controls under an auditory sensory-motor task with block design. It was observed that the connectivity of task-related networks with other networks consistently decreases(increases) in healthy controls when switching to(from) the task condition (in ~8s), a phenomenon which was not as much pronounced in the schizophrenia patients.

14:00         3677.     Minimum Resolvable Latency Difference of BOLD Responses at 7T Using Autoregressive Modeling

Santosh Bahadur Katwal1, James Christopher Gatenby2, John C. Gore3, Baxter P. Rogers4

1Electrical Engineering and Computer Science, Vanderbilt University Institute of Imaging Science (VUIIS), Nashville, TN, USA; 2Radiology and Radiological Sciences, Vanderbilt University Institute of Imaging Science (VUIIS), Nashville, TN, USA; 3Biomedical Engineering, Physics and Astronomy, Radiology and Radiological Sciences, Vanderbilt University Institute of Imaging Science (VUIIS), Nashville, TN, USA; 4Biomedical Engineering, Radiology and Radiological Sciences, Vanderbilt University Institute of Imaging Science (VUIIS), Nashville, TN, USA

Functional MRI (fMRI) at 7T has high signal-to-noise ratio (SNR) and high spatial and temporal resolution, which improve our ability to detect small differences in latency of the BOLD response. The differences in latency can imply causal relationships giving measures of directed influence of one neuronal system on another. We used Multivariate autoregressive (MAR) modeling and Granger causality to determine the directed influence measures and minimum resolvable latency difference of the BOLD response at 7T. Latencies, as low as 112 ms, were resolved in a single subject with just 16 trials. Bootstrapping was performed to obtain 95% confidence intervals on the results.

14:30         3678.     New Tools for Analysis of MRI Datasets

Robert W. Cox1, Ziad S. Saad1, Gang Chen1, Daniel R. Glen1, Richard C. Reynolds

1National Institute of Mental Health, Bethesda, MD, USA

New features in the AFNI software package.

15:00         3679.     Slice-Timing Correction Affects Functional MRI Noise, Model Fit, Activation Maps, and Physiologic Noise Correction

Keith Michael Vogt1,2, James W. Ibinson3, Robert H. Small1,2, Petra Schmalbrock4

1Anesthesiology, The Ohio State University, Columbus, OH, USA; 2Biomedical Engineering, The Ohio State University, Columbus, OH, USA; 3Anesthesiology, University of Pittsburgh Medical Center, Pittsburgh, PA, USA; 4Radiology, The Ohio State University, Columbus, OH, USA

Interleaved slice-timing correction (STC) in the analysis of pain functional MRI data was investigated for its effects on timecourse temporal standard deviation, model fit, activation maps, and slice-wise respiratory noise correction. Interaction between slice-timing and respiratory correction was demonstrated for all three FMRI study outcome measures. Both corrections caused decreases in timecourse noise and the model fit improvements from STC were much smaller than from respiratory correction. This indicates that STC affects the impact of respiratory noise correction and also that respiratory correction is more important than STC in the detection of block-design task FMRI activation.

 
Exhibit Hall 2-3                    Wednesday 13:30-15:30          Computer 37

13:30         3680.     Standardized and Automatic Framework for Functional Connectivity Analysis: Functional Correlation Matrix and Sorted Index Curve

Nan-kuei Chen1, Ying-hui Chou2, Lawrence P. Panych3,4, David J. Madden1, Allen W. Song1

1Brain Imaging and Analysis Center, Duke University, Durham, NC, USA; 2Occupational Therapy, Fu Jen Catholic University, Taipei, Taiwan; 3Radiology, Brigham and Women's Hospital, Boston, MA, USA; 4Harvard Medical School, Boston, MA, USA

Here we report an automatic post-processing pipeline to reliably identify functionally correlated regions in resting-state fMRI data. In comparison to existing analysis methods that are optimized for detecting functionally connecting brain regions (e.g. ICA), our new approach provides a comprehensive view of the functional connectivity across the whole brain and is better suited for identifying brain regions with low connectivity, without a prior assumption. We have successfully identified several brain regions that are functioning more independently from other cortical regions. We expect the developed method can reliably identify brain regions that are functionally deficient due to neurological diseases.

14:00         3681.     A Novel Activation Threshold Selection for FMRI Data Using Order Statistics

Rajesh Ranjan Nandy1

1Psychology and Biostatistics, University of California, Los Angeles, CA, USA

An important consideration fMRI is to choose the right threshold for activation. This is complicated by the temporal autocorrelation in fMRI data and the multiple testing involved in detecting activations. An ReML approach implemented in SPM2 to correct for the temporal autocorrelation but cannot eliminate the effects of inherent low frequency processes in resting brain. Also, the popular Gaussian Random Field approach to adjust for multiple comparison is usually not a vast improvement over the Bonferroni correction. We propose a novel approach using order statistics that adjusts for multiple comparison as well as the low frequency processes. No correction for temporal autocorrelation is necessary.

14:30         3682.     Function Lateralization Through Measuring Coherence Laterality

Ze Wang1, John Pluta2, Dawn Mechanic-Hamilton2, Simon Glynn2, John A. Detre2

1Psychiatry, University of Pennsylvania, Philadelphia, PA, USA; 2Neurology, University of Pennsylvania, Philadelphia, PA, USA

We proposed a data-driven approach for brain function lateralization using the coherence difference of functional MRI (fMRI) data in homologous regions-of-interest (ROI) in each hemisphere. A lateralized motor task data was used to demonstrate that coherence laterality (CL) within the functional ROI identified the correct function laterality as compared to data acquired at rest. In patients with unilateral epilepsy, CL in a hippocampus-parahippocampus-fusiform (HPF) ROI predicted the correct memory laterality, and the CL index significantly differentiated the right side group to the left side group. By contrast, normal controls showed a symmetric HPF CLI distribution.

15:00         3683.     A Technique to Detect Outliers Automatically in Multi-Site FMRI Data

Andrew Mario Michael1,2, Stefi A. Baum2, Vince D. Calhoun1,3

1MIND Research Network, Albuquerque, NM, USA; 2Center for Imaging Science, Rochester Institute of Technology, Rochester, NY, USA; 3ECE, University of New Mexico, Albuquerque, NM, USA

Brain data acquisition from multiple sites is necessitated to increase the biodiversity of subjects and to improve the significance of results. However, it is nearly impossible to keep all the variables involved in data collection identical across sites and this makes outlier detection hard. In fMRI studies outliers are usually identified by the cumbersome and subjective process of visually inspecting individual subject's brain images. In a multisite setting with a large number of subjects this can be a very difficult task. We introduce a simple, easy to implement and efficient technique with minimal human intervention to more accurately detect outliers.

 
Exhibit Hall 2-3                    Thursday 13:30-15:30          Computer 37

13:30         3684.     Wavelet Shrinkage Versus Gaussian Spatial Filtering of Functional MRI Data

Ruxandra Mutihac1, Radu Mutihac2

1Experimental Psychology, University of Oxford, Oxford, UK; 2Electricity and Biophysics, University of Bucharest, Bucharest, Romania

Wavelets provide orthonormal bases for multiresolution analysis and decorrelation of nonstationary, scaling, scale-invariant, and fractal processes in time, space, or both, which is the case in neuroimaging. Scale-varying wavelet-based methods for hypothesis testing of brain activation maps circumvent the need to specify a priori the size of signals expected and, therefore, the optimal choice of smoothing kernel required by Gaussian filtering. Wavelet-based methods are likely to provide an overall richer characterization of distributed brain activation. Discrete wavelet transform also exhibits decorrelating properties, which amounts to mutually independence of the hypothesis tests on the wavelet coefficients and yields potential benefits in the optimal control of false positives.

14:00         3685.     Using Real-Time FMRI to Control a Dynamical System

Anders Eklund1,2, Henrik Ohlsson3, Mats Andersson1,2, Joakim Rydell1, Anders Ynnerman2,4, Hans Knutsson1,2

1Div. of Medical Informatics, Dept. of Biomedical Engineering, Linköping University, Sweden; 2Center for Medical Image Science and Visualization (CMIV), Linköping, Sweden; 3Div. of Automatic Control, Dept. of Electrical Engineering, Linköping University, Sweden; 4Div. for Visual Information Technology and Applications, Dept. of Science and Technology, Linköping University, Sweden

We present an fMRI based brain computer interface (BCI). The brain and the computer are linked by fMRI and work as a controller for a dynamical system. The dynamical system consists of a cart with an inverse pendulum mounted on it. A neural network is used to classify between rest, left hand and right hand activity. The classification computed by the neural network is used as an input to the dynamical system. The BCI runs in real-time and a new control signal is computed once a second. The subject was able to balance the inverse pendulum for 7 minutes.

14:30         3686.     Multivariate Analysis of the Default-Mode Network in Healthy Subjects at Rest

Paola Valsasina1, Maria Assunta Rocca1,2, Paolo Misci1, Elisabetta Pagani1, Andrea Falini3, Massimo Filippi1,2

1Neuroimaging Research Unit, Scientific Institute Hospital San Raffaele, Milan, Italy; 2Department of Neurology, Scientific Institute Hospital San Raffaele, Milan, Italy; 3CERMAC, Scientific Institute Hospital San Raffaele, Milan, Italy

Aim of this study was to combine in a multivariate analysis several methods for the assessment of resting state (RS) fMRI data, including functional connectivity (FC), regional homogeneity (ReHo), amplitude of low-frequency fluctuations (ALFF) and independent component analysis (ICA), focussing in particular on the default-mode network (DMN). FC, ReHo and ICA were able to find a spatial pattern, consistent across approaches, resembling the DMN. The regional information given from all approaches was only partially correlated. The combined used of all these methods in a multivariate analysis might be useful to have a more global description of the RS networks.

15:00         3687.     Watching the Brain Going to Sleep: A Dynamic ICA Approach

Michael Czisch1, Renate Wehrle1, Victor I. Spoormaker1, David Höhn1, Henning Peters1, Florian Holsboer1, Philipp G. Sämann1

1Max-Planck-Institute of Psychiatry, Munich, Germany

Independent component analysis (ICA) has recently gained broad interest in the field of fMRI as the method allows for hypothesis-free analysis of functional imaging data. Resting state networks can reliably be detected using ICA. Today, most research focuses on the default mode network (DMN), comprising cerebral regions with increased activity during rest as compared to specific tasks, and assumed to be linked to intrinsic awareness1-3. Using sleep as an example of transient changes in brain activation, we propose a new iterative ICA to follow changes in the DMN integrity over time.

 


 
fMRI Mechanism & Applications
Exhibit Hall 2-3                    Monday 14:00-16:00          Computer 38

14:00         3688.     The Intrinsic Activity of the Brain Can Be Modulated by Cognitive Load

Tommaso Gili1,2, Federico Giove1,2, Vittorio Iacovella2, Emiliano Macaluso3, Bruno Maraviglia2,3

1Enrico Fermi Centre, Rome, Italy; 2Physics, Sapienza University of Rome, Rome, Italy; 3IRCCS Santa Lucia Foundation, Rome, Italy

Attention-demanding cognitive tasks not only increase activity in regions whose function supports task execution, but also trigger activity decreases in regions supporting task-unrelated processes. The set of brain regions that de-activates during goal-oriented tasks has been termed “the default mode network” (DMN). Here we asked whether the level of cognitive load (n-back memory tasks) modulates the pattern of correlated activity within the DMN. In addition our analyses of functional connectivity fMRI also looked for possible effects of cognitive load on the correlation between the default mode network and fronto-parietal regions that activate during cognitive tasks.

14:30         3689.     fMRI Group Analysis with Spatial Bayesian Variable Selection

Rajesh Ranjan Nandy1, Brad Mcevoy2

1Psychology and Biostatistics, University of California, Los Angeles, CA, USA; 2University of California, USA

In recent times, Bayesian approaches have been increasingly popular in fMRI data analysis due to its easy interpretability and its ability to incorporate anatomical information or other expert knowledge into the model. In a classical framework this can be achieved only with segmentation or a region of interest (ROI) based approach, which is too restrictive. One popular Bayesian approach that does not suffer from the problems of the classical approach is the spatial Bayesian variable selection (SBVS) framework introduced by Smith which can only be applied to single subject analysis. Here we modify and extend SBVS to fMRI group analysis. Furthermore, this model can account for anatomical heterogeneity across subjects.

15:00         3690.     Fusion of Structural-Functional Brain Images Reveals Differences in Schizophrenia in a Multi Site Study

Andrew Mario Michael1,2, Stefi A. Baum2, Vince P. Clark1, Rex Jung1, Kelvin O. Lim3, Tonya White3, Beng C. Ho4, Randy L. Gollub5, Vince D. Calhoun1

1MIND Research Network, Albuquerque, NM, USA; 2Center for Imaging Science, Rochester Institute of Technology, Rochester, NY, USA; 3University of Minnesota, Minneapolis, MN, USA; 4University of Iowa, Iowa City, IA, USA; 5Psychiatry and Radiology, Massachusetts General Hospital, Charlestown, MA, USA

Data fusion approaches can help to find hidden traits in complex disorders such as schizophrenia. We examine all possible combinations of inter-voxel cross-correlations between structural and functional data and where these correlations show patient/control differences. We present efficient approaches to compute the structure-function correlations and to evaluate their statistical properties. We find that cross-correlations between gray matter concentration and functional MRI data from a sensorimotor task are significantly lower in patients. The cerebellum showed more positive correlations with functional data in controls versus patients and the cingulum showed more negative correlations in patients.

15:30         3691.     BRAIN AREAS ATTUNED to CHANGES in the PROSODIC FOCUS of REPEATED SPOKEN SENTENCES – an FMRI STUDY

Michael Inspector1, David Manor2, Tammar Kushnir2, Yael Gogol1, Noam Amir3, Avi Karni1,2

1Laboratory of Brain Imaging and learning, Haifa University, Haifa, Israel; 2Dept. of Diagnostic Imaging, MRI Unit, The Chaim Sheba Medical Center, Tel Hashomer, Israel; 3Communications Disorders, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel

Are brain areas attuned to a change in the location of the prosodic focus (i.e., intonation)? Participants listened to repeated sentences with a fixed intonation. In a subsequent fMRI-test phase, reaction times were slower and neuronal activity was enhanced for sentences presented with the trained wording but with new intonations, compared to unchanged intonations. This enhancement was found in bilateral anterior temporal cortex, left inferior frontal gyrus and right posterior middle temporal gyrus. The results suggest that these areas are selectively tuned to the prosodic structure of sentences, including the processing of slow pitch variations that mark the prosodic focus.

 
Exhibit Hall 2-3                    Tuesday 13:30-15:30          Computer 38

13:30         3692.     Mapping  Human Somatosensory Cortex with FMRI at 7 T:  Travelling Wave and Event-Related Paradigms

Rosa Maria Sanchez Panchuelo1, Sue Francis1, Denis Schluppeck2, Richard Bowtell1

1Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham, UK; 2School of Psychology, University 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 using a travelling wave paradigm and in characterising the spatial variation of the haemodynamic response to vibrotactile digit stimulation with an event related design at 1 mm isotropic resolution. Results were displayed on flattened representations of the somatosensory cortex. Activation clearly showed the expected digit ordering along the postcentral gyrus. The haemodynamic delay estimated from the travelling wave paradigm is in good agreement with the delay measured using the event-related paradigm.

14:00         3693.     A Magnetic Resonance Compatible Stepper (MARCOS) for FMRI Investigation of Gait

Christoph Hollnagel1, Ningbo Yu1, Armin Blickenstorfer1,2, Peter Wolf1, Volker Dietz3, Spyros Kollias2, Robert Riener1

1D-MAVT, ETH, Zurich, Switzerland; 2University Hospital Zurich, Zurich, Switzerland; 3University Hospital Balgrist, Zurich, Switzerland

Rehabilitative training of spinal cord injured patients is only successful, if patients are not immobile over a long time. An immobile phase may result in degradation of nerve cells. Mechanism leading to degradation of nerve cells and effects of rehabilitative training are not well understood but knowledge about this issue is desired to evaluate and improve rehabilitative training. Thus, we developed a magnetic resonance compatible stepper (MARCOS) to perform gait like movements while acquiring brain activation with functional magnetic resonance imaging fMRI. This abstract describes the device and its influence to the magnetic fields of the scanner.

14:30         3694.     Caloric and Non-Caloric Versions of a Soft Drink Differentially Affect Taste Activation Before Consumption

Paul Smeets1,2, Pascalle Weijzen2, Cees de Graaf2, Max Viergever1

1Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands; 2Division of Human Nutrition, Wageningen University, Wageningen, Netherlands

Satiation is brought about by a combination of sensory and metabolic factors.We investigated the effects of sip size (small – large) and energy content (Energy – No Energy) on taste activation by scanning subjects before and after ingestion of 450mL orangeade using fMRI. Energy content affected brain activation associated with tasting orangeade before, but not after, treatment in the amygdala, striatum and inferior temporal gyrus. Sip size had no significant effects. Our results show that the brain can distinguish between caloric and non-caloric beverages and suggest that sensory and metabolic satiation differentially affect taste activation.

15:00         3695.     Neural Correlates of Altruistic and Deontological Guilt: An FMRI Investigation in Healthy Individuals

Barbara Basile1,2, Marco Bozzali3, Emiliano Macaluso3, Francesco Mancini2

1Neuroimaging Laboratory , Santa Lucia Foundation, Rome, Italy, Italy; 2School of Cognitive Psychotherapy, Rome, Italy, Italy; 3Neuroimaging Laboratory, Santa Lucia Foundation, Rome, Italy, Italy

The neuroanatomical correlates of basic emotions have been largely investigated using functional MRI (fMRI).Guilt is a very relevant social emotion, which is involved in everyday life situations. Recently, deontological guilt and altruistic guilt have been differently characterized.

 
Exhibit Hall 2-3                    Wednesday 13:30-15:30          Computer 38

13:30         3696.     Accompanying Event-Related Decrease of Alpha Band EEG and Sustained Negative BOLD Response at Ipsilateral Primary Sensorimotor Area

Han Yuan1, Rebecca Szarkowski1, Cristina Rios1, James Ashe2,3, Bin He1,2

1Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA; 2Neuroscience, University of Minnesota, Minneapolis, MN, USA; 3Brain Sciences Center, Veterans Affairs Medical Center, Minneapolis, MN, USA

The aim of the study is to investigate the biophysical relationship between task-induced responses of BOLD-fMRI and electrophysiological signals in alpha-frequency band (8 – 13 Hz). We combined electroencephalography (EEG) and fMRI to identify the correlates of negative BOLD response in a motor paradigm. Our results showed co-localization of task-related decrease of alpha band EEG and sustained decrease of BOLD signals at the ipsilateral primary sensorimotor area, which indicates a neural correlate of negative BOLD response and suggests that decreased neural activity may cause the desynchronization of alpha rhythm.

14:00         3697.     High Resolution FcMRI: Degrees of Correlation Within the Rat Brain Finger Representation

James S. Hyde1, Christopher P. Pawela2, Bhart B. Biswal3, Rupeng Li1, Younghoon R. Cho2

1Biophysics, Medical College of Wisconsin, Milwaukee, WI, USA; 2Plastic Surgery, Medical College of Wisconsin, Milwaukee, WI, USA; 3Radiology, UMDNJ New Jersey Medical School, Newark, NJ, USA

Data for each digit were averaged across all rats and acquisitions, and the average RPCC matrix formed. Data presented here show that some parts of the rat forepaw representations are more strongly connected than others, allowing the introduction of the concept of “degrees of connectivities” within functionally defined brain systems. This information does not seem to be obtainable using fMRI.

14:30         3698.     Time Invariant BOLD Impulse Response Functions for Brief- And Long-Lasting Stimuli

Peter Herman1,2, Basavaraju G. Sanganahalli1, Hal Blumenfeld3,4, Fahmeed Hyder1,5

1Diagnostic Radiology, Yale University, New Haven, CT, USA; 2Institute of Human Physiology and Clinical Experimental Research, Semmelweis University, Budapest, Hungary; 3Neurology, Yale University, New Haven, CT, USA; 4Neurobiology, Yale University, New Haven, CT, USA; 5Biomedical Engineering, Yale University, New Haven, CT, USA

Quantitative mapping of changes in CMRO2 with BOLD calibration has become a popular modality for studying functional brain activity because it is proportional to changes in energy consumption associated with alterations in neuronal activity. The calibrated fMRI is based on steady-state tissue oxygen extraction model, and it is unclear whether calculation of CMRO2 will differ between short and long stimuli. We show that the linear convolution analysis can characterize a single transfer function for short and long stimuli, even with varying stimulation conditions. This experimental approach provides a basis for the use of calibrated fMRI in a dynamic manner.

15:00         3699.     Neurocognitive Mapping of Spatial Working Memory in Hyperthyroidism – an FMRI Study

Manisha Bhattacharya1, Subash Khushu1, Shilpi Modi1, Tarun Sekhri2, Rajendra Prasad Tripathi1

1NMR Research Centre, Institute of Nuclear Medicine and Allied Sciences, Delhi, India; 2Division of Health, Institute of Nuclear Medicine and Allied Sciences, Delhi, India

Patients with acute hyperthyroidism may show poor performance on working memory tasks due to attention deficit. Functional MRI was carried out in hyperthyroid subjects to assess the extent of cognitive deficit associated with spatial working memory. Significant BOLD activations observed in the prefrontal, middle frontal, superior parietal, middle temporal and occipital lobes in healthy subjects are attributed to attention, spatial working memory and spatial information processing. Patients with clinically diagnosed Graves’ disease showed reduced activations in these areas and additionally activated BA10 a region responsible for memory retrieval and executive functioning.

 
Exhibit Hall 2-3                    Thursday 13:30-15:30          Computer 38

13:30         3700.     Paying Attention When It Counts: The Effect of Motivation on FMRI Activity During Attentional Control

Tracy L. Luks1, Ashley Kopec2, Corby L. Dale1, Gregory V. Simpson1, Anthony Kaveh3

1Radiology, UCSF, San Francisco, CA, USA; 2Carroll University; 3UCB, Berkeley, CA, USA

Attentional control is the goal-driven allocation of attention to task-appropriate stimuli and responses, and away from distractions. Motivation is the ability to anticipate and appreciate the consequences of behavior, such as rewards or punishments. We examined interactions between neurobiological systems underlying motivation and attentional control using a Rewarded Counting Stoop task during an fMRI scan. Fourteen healthy control volunteers participated in this study. The results suggest that motivation modulates attentional control via increased activity in orbitofrontal and anterior cingulate cortex, as well as increasing arousal and sustained attention by increasing activity in thalamus and right dorsolateral prefrontal cortex.

14:00         3701.     Calibrating the BOLD Signal Revisited – Calculation of Oxygen Metabolism for Gradient- And Spin-Echo Sequence Up to 16.4T

Kamil Uludag1, Anne-Catherin Zappe1, Jozien Goense1, Nikos K. Logothetis1

1Max-Planck-Institute for biological Cybernetics, Tuebingen, Baden, Germany

A BOLD signal model as a function oxygen extraction fraction and CBV was developed in order to determine change in oxidative metabolism from combined BOLD signal and CBF measurements. The new model is an alternative model to the widely used calibrated BOLD approach initally proposed by Davis and colleagues for GRE at 1.5T. The new model, however, takes also intra-vascular MRI signal into account and is developed for both GRE and SE from 1.5T up to 16.4T. In the current study, at 4.7T and 7T using SE and GRE, oxidative metabolism change during visual stimulation was determined in macaque monkeys.

14:30         3702.     Temporal Changes of BOLD FMRI Activation in a Block Design

Arthur Peter Wunderlich1, Gregor Stuber1, Wolfgang Freund1

1Diagnostic and Interventional Radiology, Univ.-Clinic Ulm, Ulm, Baden-Württemberg, Germany

To study the temporal variability of the BOLD response, we investigated 15 healthy subjects while stimulating their index finger electrically for 52 s. Activation was repeated six times followed by rest for 26 s. Additional data were acquired starting 26 s before the first stimulation. In SPM analysis, we modelled the paradigm, activation and following rest, as one regressor per acquired volume. As reference (‘off’-condition), the resting phase before the first stimulation was chosen. The group analysis shows a slow spatial change of activation maxima during continuous stimulation and activation lasting as long as 20 s after the end of stimulation.

15:00         3703.     The Effect of Hypercapnia on Resting State FMRI

Jinsoo Uh1, Feng Xu1, Uma Yezhuvath1, Yamei Cheng1, Hong Gu2, Yihong Yang2, Hanzhang Lu1

1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA; 2Neuroimaging Research Branch, National Institute on Drug Abuse, National Institute of Health, Baltimore, MD, USA

Hypercapnia (HC) challenge provides an excellent model condition for studying brain activity. We investigated the effect of HC on Resting State Network (RSN) and compared it with that on visual-evoked BOLD signals. We found that RSN shows a reduction in both cluster size and signal amplitude due to HC challenge. We also found a similar reduction of visual fMRI signal in the same subjects. This result indicates that vascular effects such as basal CBF and venous oxygenation contribute to the reduction of RSN as they do to visual fMRI signal. Thus, caution should be used in interpreting BOLD RSN changes.

 


 
fMRI: Applications
Exhibit Hall 2-3                    Monday 14:00-16:00          Computer 39

14:00         3704.     Reward Sensitivity and Positive Affect Influence Brain Activation to Food Pictures of Different Caloric Value

Christina Gabriele Prechtl de Hernandez1, John D. Beaver2, Charlotte Croese1, Kinan Muhammed1, Gabriel Bell1, Giuliana Durighel3, Emer Hughes3, Adam D. Waldman3, Gary Frost4, Jimmy D. Bell1, Anthony P. Goldstone1

1Metabolic and Molecular Imaging Group, Imaging Sciences Department, MRC Clinical Sciences Centre, Hammersmith Hospital, Imperial College, London, UK; 2Clinical Imaging Centre, GlaxoSmithKline, Hammersmith Hospital, Imperial College London, UK; 3Robert Steiner MRI Unit, Imaging Sciences Department, MRC Clinical Sciences Centre, Hammersmith Hospital, Imperial College, London, UK; 4Department of Investigative Medicine, Hammersmith Hospital, Imperial College, London, UK

We examined how individual personality traits and mood influence regional brain activity when viewing food pictures measured by fMRI. 20 non-obese healthy adults were scanned after an overnight fast or after breakfast. There was significant activation of the ventral striatum, insula, amygdala, medial and lateral orbitofrontal cortex (OFC) when viewing high-calorie vs. low-calorie foods only when fasted. Ventral striatum, amygdala, and medial OFC activation were positively correlated with individual measures of reward sensitivity (BAS Drive and/or Reward Responsiveness) when fasted, while insula activation was positively correlated with positive affect. There was no significant correlation with negative affect or body-mass-index.

14:30         3705.     Attentional Modulation of Thermal Sensory Responses in the Human Spinal Cord

Patrick W. Stroman1, Brian Coe1, Chase R. Figley1, Jordan Leitch1, Doug P. Munoz1

1Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada

Descending control of spinal cord function has a significant influence on perceived sensations, and has important implications for the effects of trauma, if this descending control is lost or altered. Using fMRI of the healthy human spinal cord and brainstem, we observed the effects of changes in attention focus at the level of the spinal cord for the first time. The results demonstrated the greatest signal changes in the dorsal gray matter of the cervical spinal cord, as well as in the thalamus and areas involved in the descending analgesia system, when participants focused their attention on mentally-challenging multiple-choice questions.

15:00         3706.     Effects of High and Low Spatial Filtering and Spatial Location of Fearful Faces on Amygdala and Fusiform Gyrus Activity

Carmen Morawetz1,2, Juergen Baudewig1, Stefan Treue2,3, Peter Dechent1

1MR-Research in Neurology & Psychiatry, Medical Faculty, Georg August University, Goettingen, Germany; 2Cognitive Neuroscience Laboratory, German Primate Center, Goettingen, Germany; 3Bernstein Center of Computational Neuroscience, Goettingen, Germany

Faces provide complex visual information at multiple spatial frequencies (low/high spatial frequency; LSF/HSF). It has been demonstrated that the amygdala is preferentially activated by LSF filtered faces. We investigated the impact of stimulus eccentricity and different spatial frequencies on face processing in the amygdala using fMRI. Pairs of images (filtered face and Fourier transformed image) were presented at one of two eccentricities. Subjects indicated on which side the face appeared. The results showed that the amygdala is not preferentially engaged in the processing of LSF aspects of emotional expressions as both frequency ranges are equally implicated in face perception.

15:30         3707.     Using FMRI to Demonstrate Tolerance to the Rewarding and Anxiolytic Effects of Alcohol in Heavy Drinkers

Jodi Gilman1, Vijay Ramchandani1, Tess Crouss1, Daniel Hommer1

1Laboratory of Clinical and Translational Studies, National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA

Tolerance to a drug can be defined as diminished effect with continued use. This study characterizes the BOLD response to alcohol administration in social drinkers (SDs) and heavy drinkers (HDs). We infused both groups with ethanol or placebo while they underwent fMRI scans and viewed facial images. HDs reported less intoxication than SDs, and also demonstrated lower activity in the nucleus accumbens. While alcohol attenuated amygdala reactivity to fearful faces in the SDs, it did not do so in the HDs. This study suggests that at equivalent blood alcohol concentrations, HDs experience reduced subjective and neural effects of intoxication.

 
Exhibit Hall 2-3                    Tuesday 13:30-15:30          Computer 39

13:30         3708.     Activation of Inferior Frontal Gyrus During Response Inhibition: Effects of Citalopram and Acute Tryptophan Depletion Depend on Neocortical 5-HT2A Receptor Levels

Julian Macoveanu1,2, Bettina Hornboll1,3, Rebecca Elliott4, Hartwig Siebner1,3, David Erritzoe3,5, Olaf B. Paulson1,3, Gitte M. Knudsen3,5, James B. Rowe3,6

1Danish research center for MR, Copenhagen University Hospital, Hvidovre, Denmark; 2Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital , Copenhagen, Denmark; 3Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Copenhagen, Denmark; 4Neuroscience and Psychiatry Unit, University of Manchester, Manchester, UK; 5Neurobiology Research Unit, Copenhagen University Hospital, Copenhagen, Denmark; 6Department of Clinical Neurosciences, Cambridge University, Cambridge, UK

Inhibiting actions is associated with the inferior frontal gyrus (IFG) and is regulated by serotonin. Here we explore the link between the serotonin receptor type 5-HT2A and activity in IFG during response inhibition. 17 subjects performed a Go/No-Go task during fMRI, with treatments to acutely increase (citalopram) or decrease (acute tryptophan depletion, ATD) serotonin, or no treatment. We also used 18-F-altanserin positron emission tomography to map 5-HT2A receptor binding. Individuals with low 5-HT2A had greater activation of IFG after ATD. Individuals with high 5-HT2A had greater activation after citalopram. Conclusion: effects of serotonergic treatments depend on individual differences in 5-HT2A.

14:00         3709.     A High-Field Human Brain Interface Using a Modular Virtual Environment System for Real Time FMRI

Charles Mueller1, Ramona Grzeschik1, Maurice Hollmann1, Sebastian Baecke1, Ralf Lützkendorf1, Johannes Bernarding1

1Department of Biometry and Medical Informatics, Medical Faculty, Otto-von-Guericke-University Magdeburg, Magdeburg, Sachsen-Anhalt, Germany

The field of virtual reality (VR) environments and neurofeedback applications for functional magnetic resonance imaging is huge. Some groups applied VR for fMRI-based neurofeedback paradigms and human brain interfaces. Our aim is the development and implementation of a VR paradigm library with some common VR scenes and a well-structured modular virtual environment system that allows the import of these virtual reality measurement paradigms just by few mouse clicks. For testing, we used our system as a real time human brain interface where subjects navigated through a three-dimensional maze using brain activations of different cortical areas.

14:30         3710.     Separate Neural Systems for Evaluating Risks and Reward in Decision Making

Julian Macoveanu1,2, Jon Wegener1,2, Arnold Skimminge1, Bettina Hornboll1,2, Rebecca Elliott3, Hartwig Siebner1,2, Olaf B. Paulson1,2, James B. Rowe2,4

1Danish research center for MR, Copenhagen University Hospital, Hvidovre, Denmark; 2Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Copenhagen, Denmark; 3Neuroscience and Psychiatry Unit, University of Manchester, Manchester, UK; 4Department of Clinical Neurosciences, Cambridge University, Cambridge, UK

When making a decision, the risk can be expressed as the probability of wining vs. losing, or the outcome winnings vs. losses. We used a novel gambling task with 30 subjects in fMRI to study the different roles of fronto-striatal systems in the integration of probability vs. outcome. The probability of winning correlated with activity in the rostral Ventral Striatum (VS), dorsal anterior-cingulate (ACC) and orbitofrontal cortex. The magnitude of winnings correlated with caudal-VS and subgenual-ACC activity. Conclusion: separate regions of VS and ACC are sensitive to different aspects of risk, even when the expected utility of choices is equated.

15:00         3711.     A Functional Dissociation Between the Left and the Right Cerebellum During Sensorimotor Synchronization: A BOLD FMRI Study

Janine D. Bijsterbosch1, Kwang-Hyuk Lee1, Daniel T. Tsoi1, Peter W R Woodruff1, Iain D. Wilkinson2

1Academic Psychiatry, University of Sheffield, Sheffield, South Yorkshire, UK; 2Academic Radiology, University of Sheffield, Sheffield, South Yorkshire, UK

Using temporally-correlated fMRI we investigated the brain networks for motor timing and error correction during a sensorimotor synchronization paradigm. Motor timing activates a functional network that includes the right cerebellum and primary motor and sensory cortices. Error correction engaged the left cerebellar cortex and structures in the inferior parietal and frontal cortices. These results indicate a dissociable functional lateralization within the cerebellum and provide insights into the cortico-cerebellar functional networks for timing and error correction.

 
Exhibit Hall 2-3                    Wednesday 13:30-15:30          Computer 39

13:30         3712.     Simultaneous Dual-FMRI, Sparse Temporal Scanning of Human Duetters at 1.5 and 3 Tesla

Lawrence M. Parsons1, Evangelos T. Himonides2, Nyssa Craig3, Monica Vakil4, Robert S. Turner5, Iain D. Wilkinson6

1Psychology, University of Sheffield, Sheffield, South Yorkshire, UK; 2Institute of Education,, University of London, London, UK; 3Radiology, University of Sheffield, Sheffield, UK; 4Pediatrics, Children's Hospital, Harvard Medical School, Boston, MA, USA; 5Max Planck Institute of Human Cognitive and Brain Sciences, Leipzig, Germany; 6Radiology, University of Sheffield, Sheffield, South Yorkshire, UK

We report a simultaneous dual fMRI study, using sparse temporal sampling, of pairs of musicians singing complex and simple folksongs. Each pair of duetters performed under three conditions: solo singing, singing in unison with a partner, and singing in unison with a computerized piano performance. Each pair of duetters performed all conditions twice, once in the 1.5 scanner and once in the 3T scanner. The results implicate a distributed set of brain areas involved in the online coordination of interactive entrainment of human duetters, and provide the basis for a wider use of simultaneous dual-scanning paradigms.

14:00         3713.     Impact of Noise-Modelling Methods on Test-Retest Reliability of a Covert Verbal Fluency FMRI Task Across 2 Sites

Jonathan O'Muircheartaigh1, Christian Vollmar2, Gareth Barker3, Mark Symms2, Veena Kumari4, Pam Thompson2, John Duncan2, Matthias Koepp2, Mark Richardson1

1Department of Clinical Neuroscience, Institute of Psychiatry, Kings College London, London, UK; 2The National Society for Epilepsy and the Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, UK; 3Department of Clinical Neuroscience, Centre for Neuroimaging Sciences, Institute of Psychiatry, Kings College London, London, UK; 4Department of Psychology, Institute of Psychiatry, Kings College London, London, UK

Here, a simple covert verbal fluency task is used to assess reliability of fMRI results across sites and sessions using voxelwise and region-based intraclass correlation techniques. The impact of modelling for motion is investigated.

14:30         3714.     Rapid Digit Mapping in the Human Brain at 3T

Jolinda Smith1, Sergei Bogdanov1, Scott Frey1

1Lewis Center for Neuroimaging, University of Oregon, Eugene, OR, USA

We have developed an MRI compatible pneumatic stimulation system for the mapping of hand and face representations in the human brain. The system is highly flexible and easily accommodates subjects with different body and hand sizes. By using this device together with a BOLD EPI imaging sequence with 1.5 mm in-plane resolution we have been able to produce detailed maps of the somatosensory representation of the digits in human subjects with an acquisition time totaling approximately 14 minutes.

15:00         3715.     The Cortical Representation of Taster Status: Reducing the Heterogeneity of Group FMRI

Sally Eldeghaidy1, Luca Marciani2, Francis McGlone3, Tracey Hollowood4, Joanne Hort4, Kay Head1, Andy Taylor4, Johanneke Busch5, Jason Stokes6, Robin Spiller2, Penny Gowland1, Susan Francis1

1SPMMRC, University of Nottingham, Nottingham, UK; 2WDDC, University of Nottingham, UK; 3Unilever R&D, Cheshire, UK; 4Division of Food Sciences, University of Nottingham, UK; 5Unilever Food and Health Research Institute, Vlaardingen, Netherlands; 6Unilever Corporate R&D, Colworth, UK

The cortical representation of fat is mapped against taster status to test the hypothesis that taster status is mediated by sensory responses. The BOLD response is shown to be highly correlated to taster status (super-tasters>medium-tasters>non-tasters) in somatosensory areas (SI, SII, mid- and posterior insula) and reward areas (amygdala and anterior cingulate) but not in the classical primary taste area (anterior insula), supporting the sensory basis of taster status. These results also show that the inter-subject variance in the BOLD response can be improved by selecting subjects with a particular taster status for group analysis, with super-tasters improving detection power.

 
Exhibit Hall 2-3                    Thursday 13:30-15:30          Computer 39

13:30         3716.     Functional MRI of Central Motor Drive During Muscle Contractions

Jill M. Slade1,2, Sean C. Forbes3, Ryan M. Francis3, Robert W. Wiseman1,3, Ronald A. Meyer1,3

1Radiology, Michigan State University, East Lansing, MI, USA; 2Manipulative Medicine, Michigan State University, East Lansing, MI, USA; 3Physiology, Michigan State University, East Lansing, MI, USA

An area of primary sensorimotor cortex in which functional MRI signal changes are highly correlated with the force of isometric handgrip contractions was identified in adult subjects. Activity in this area was then measured during 3 min constant low-force contractions performed either with or without forearm ischemia. The signal increase in the force-correlated region was initially similar in both conditions, but by the end of the contraction was 2-fold greater during ischemia. The results are consistent with the notion that functional MRI of the primary sensorimotor area can be used as an index of central motor drive.

14:00         3717.     Heart-Rate Based Analysis of FMRI Data Can Reveal 'lost' Signal Intensity Changes in the Spinal Cord Associated with Distinct Phases of the Human Sexual Response

Natalie Kozyrev1, Chase R. Figley1, Patrick W. Stroman1,2

1Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada; 2Departments of Diagnostic Radiology and Physics, Queen's University , Kingston, Ontario , Canada

Here we demonstrate that analysis of spinal fMRI data using the heart-rate as a model paradigm of the sexual response represents a more accurate and sensitive method than performing analysis of identical data using a block stimulation paradigm as a model. Signal intensity changes are revealed in regions of the spinal cord salient to sexual responses, when analyzed with the heart-rate as an indicator of the response, that were previously obscured by analyses using the conventional block paradigm. Cardiac analyses of fMRI data may be extended to studies of other human functions involving the autonomic nervous system.

14:30         3718.     Cortical Responses to a Rectal Balloon Pain Paradigm

Luca Marciani1, David Humes1, Kay Head2, Tom White2, Jan Smith1, Debbie Bush1, Matt Brookes2, Claire Stevenson2, Peter G. Morris2, Robin C. Spiller1, Penny A. Gowland2, Sue T. Francis2

1Nottingham Digestive Diseases Centre Biomedical Research Unit, University of Nottingham, Nottingham, UK; 2Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham, UK

Previous fMRI studies suggested that painful barostat balloon rectal distension activates a widespread network of brain structures. The nature of the cortical response to the paradigm has been investigated, and improved correlations have been found when comparing to the ramps of the distension, rather than the full period of the distension. Similar areas were identified by MEG, which, given its direct nature, also gives it potential to provide insight into the timescale of electrical power changes in the cortical areas of interest identified using fMRI.

15:00         3719.     Faces Around the Norm – FMRI of the Face Distortion Aftereffect

Peter Dechent1, Carmen Morawetz1,2, Jürgen Baudewig1, Stefan Treue2,3, Mike Webster4, Daniel Kaping2

1MR-Research in Neurology and Psychiatry, University Göttingen, Göttingen, Germany; 2Cognitive Neuroscience Laboratory, German Primate Center, Göttingen, Germany; 3Bernstein Center of Computational Neuroscience, Göttingen, Germany; 4Department of Psychology, University of Nevada, Reno, NV, USA

Individual faces are thought to be perceived according to how they deviate from a norm or average face. We directly probed the neural basis for a norm in face perception by using fMRI to measure responses to normal faces after adapting to abnormal (distorted) faces, or vice versa. Paralleling perceptual aftereffects, hemodynamic response changes were much stronger for the normal faces following the distorted adaptor. This asymmetry suggests that normal faces reflect more neutral response states in the representation of faces, consistent with a norm-based code in face-selective cortical areas.

 


 
fMRI Applications & Animal Models
Exhibit Hall 2-3                    Monday 14:00-16:00          Computer 40

14:00         3720.     Functional MRI of Visual Development in Rat Superior Colliculus

Kai Xing1,2, Kevin C. Chan1,2, Matthew M. Cheung1,2, Ed X. Wu1,2

1Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China; 2Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong SAR, China

This study aimed to use visual stimulation in rats to determine age-related visual development from the time of eyelid opening to adulthood. By studying BOLD-fMRI measurements of rat superior colliculus, we demonstrated that the regional BOLD visual response in these animals undergoes a systematic increase in amplitude with age especially during the 3rd postnatal week.

14:30         3721.     BOLD Impulse Response Functions in the Somatosensory Cortex: Implications for CMRO2 Calculation

Peter Herman1,2, Basavaraju G. Sanganahalli1, Hal Blumenfeld3,4, Fahmeed Hyder1,5

1Diagnostic Radiology, Yale University, New Haven, CT, USA; 2Institute of Human Physiology and Clinical Experimental Research, Semmelweis University, Budapest, Hungary; 3Neurology, Yale University, New Haven, CT, USA; 4Neurobiology, Yale University, New Haven, CT, USA; 5Biomedical Engineering, Yale University, New Haven, CT, USA

Quantitative mapping of changes in CMRO2 with BOLD calibration has become a popular modality for studying functional brain activity with different somatosensory stimulations. CMRO2 calculation requires multi-modal measurements of BOLD, CBV, CBF and/or neural activity, which can vary in different areas of the somatosensory cortex. We measured BOLD and LFP responses in the forelimb and the whisker barrel cortex. The amplitudes of the BOLD and LFP responses were smaller in the whisker area. We calculated BOLD impulse response functions in these areas to reveal whether or not the different BOLD responses can be explained by the different neural responses.

15:00         3722.     Sensory Integration Studies in Rodent by FMRI: Intra- And Inter-Hemispheric Effects

Basavaraju G. Sanganahalli1, Peter Herman1,2, Hal Blumenfeld3, Fahmeed Hyder1,4

1Diagnostic Radiology, Yale University, New Haven, CT, USA; 2Institute of Human Physiology and Clinical Experimental Research, Semmelweis University, Budapest, Hungary; 3Neurology, Yale University, New Haven, CT, USA; 4Biomedical Engineering, Yale University, New Haven, CT, USA

We investigated intra- and inter-hemispheric effects of the rat somatosensory cortex by fMRI. We used bilateral forepaw stimulation for studying inter-hemispheric effects and whisker and forepaw of same side of the body to study intra-hemispheric effects. We found augmented BOLD signal in the contralateral forepaw region when both paws were stimulated as compared to independent stimulation of an individual paw. We found similar BOLD signal enhancement in the forelimb region when the whisker stimulation was presented simultaneously, however the whisker region was unaffected. These results suggest some hierarchical differences for intra- and inter-hemispheric interactions within the somatosensory cortex.

15:30         3723.     Comparision of  α-Chloralose and Domitor Anesthesia for FMRI and Electrophysiology Studies

Basavaraju G. Sanganahalli1, Peter Herman1,2, Hal Blumenfeld3, Fahmeed Hyder1,4

1Diagnostic Radiology, Yale University, New Haven, CT, USA; 2Institute of Human Physiology and Clinical Experimental Research, Semmelweis University, Budapest, Hungary; 3Neurology, Yale University, New Haven, CT, USA; 4Biomedical Engineering, Yale University, New Haven, CT, USA

We investigated the cortical hyperemic responses to forepaw stimulation under α-chloralose and domitor anesthesia. We evaluated the frequency-dependent activation of rat somatosensory cortex at 11.7T for two anesthetics. BOLD/CBV responses peaked at 3Hz stimulation under α-chloralose and at 9 Hz under domitor anesthesia. The magnitude of the responses was significantly higher under α-chloralose as compared to domitor. Differences in baseline spontaneous neuronal activity may be responsible for differential response magnitudes in BOLD and CBV under these two anesthetics. These results will benefit interpretation of fMRI experiments in anesthetized rodents as well as the understanding of brain function.

 
Exhibit Hall 2-3                    Tuesday 13:30-15:30          Computer 40

13:30         3724.     Estrogen Increases Hippocampal Activity and Functional Connectivity in Postmenopausal Women

Sijia Gao1, Ke Xu1

1Radiology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China

Estrogen replacement therapy (ERT) has been increasingly applied clinically to prevent perimenopausal symptoms, osteoporosis, and colon cancer. Recent researches also demonstrated ERT may have the benefit to improve the cognitive function and prevent hippocampus atrophy. Less is known, however, what the brain responses to estrogen would be in imaging domain. To better understand the neuronal protective mechanisms of estrogen, here we investigated the BOLD and functional connectivity responses induced by acute estrogen administration in postmenopausal women.

14:00         3725.     Sensory-Induced Sub-Cortical Activations in Rat Brain by FMRI

Basavaraju G. Sanganahalli1, Peter Herman1,2, Christopher J. Bailey3, Douglas L. Rothman1,4, Fahmeed Hyder1,4

1Diagnostic Radiology, Yale University, New Haven, CT, USA; 2Institute of Human Physiology and Clinical Experimental Research, Semmelweis University, Budapest, CT, Hungary; 3CFIN, Aarhus University, Aarhus, Denmark; 4Biomedical Engineering, Yale University, New Haven, CT, USA

Current understanding about BOLD signal and the underlying neurophysiology is based predominantly on functions of the cerebral cortex. BOLD activations of subcortical regions, in contrast, are hard to detect because of low sensitivity and/or difficult access. The goal of the present work was to study subcortical mechanisms underlying dispersed cortical activations during sensory stimulation in rat brain by fMRI. Our results demonstrate reproducible thalamus and superior colliculus activity during forepaw, whisker, and visual stimuli in anesthetized rats. These experiments should provide insights into understudied interactions between cortical and subcortical areas and provide a mechanistic basis to understand multisensory integration.

14:30         3726.     MR Perfusion of Non-Small Cell Lung Cancer in Transgenic SCID Mice Overexpressing VEGF

Yeun-Chung Chang1, Ang Yuan2, Yi-Chien Lu3,4, Jyh-Horng Chen4, Pan-Chyr Yang2

1Department of Medical Imaging, National Taiwan University Hospital , Taipei, Taiwan; 2Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan; 3Department of Medical Imaging, National Taiwan University Hospital, Taipei, Taiwan; 4Interdisciplinary MRI/MRS Lab, Department of Electric Engineering, National Taiwan University, Taipei, Taiwan

This study is to evaluate the feasibility of dynamic contrast enhanced (DCE) magnetic resonance imaging (MRI) in subcutaneously transplanted vascular endothelial growth factor (VEGF) overexpressing NSCLC in a severe combined immunodeficiency (SCID) mice model. Tumor growth accompanied with increased vascularity characterized with higher Ktrans and Kep, values indicating increased transfer constant due to vascular permeability. Perfusion MRI study is feasible for evaluating NSCLC with VEGF overexpressing transgenic SCID mice model. This study enables the future implementation of DCE perfusion MRI study in SCID mice model of lung cancer.

15:00         3727.     An Investigation Into the Effects of Anaesthesia Upon Regional Functional Modulation in the Rat Brain: A PhMRI Study

Tamsin A. Langley1, Nick Jones1, Michael J. O'Neill2, Steve C.R. Williams3

1Neuroimaging Research Group, Institute of Psychiatry, King's College London, London, UK; 2Neurodegeneration Drug Team, Eli Lilly & Co., Surrey, UK; 3Neuroimaging Research Group, Institute of Psychiatry, Lonfon, UK

Presently, anaesthesia is commonly utilised in small animal fMRI and phMRI. As yet there is no standardization for anaesthetic protocols, despite the fact that different anaesthetics affect factors such as cerebral blood flow, respiration and ultimately neurovascular coupling as well as influencing neurotransmitter systems. With the increase in the application of BOLD imaging in neuroscience drug discovery, it is pertinent that the most appropriate anaesthetic is chosen, specific to experimental design. In this study we investigate the effect of two anaesthetics, urethane and isoflurane on the regional functional modulation in the rat brain following an acute fluoxetine challenge.

 
Exhibit Hall 2-3                    Wednesday 13:30-15:30          Computer 40

13:30         3728.     Functional Connectivity Networks Associated with Dorsal and Ventral Striatum

Aman Goyal1, Wendy Ringe2, Kaundinya Gopinath3,4, Robert Haley4, Richard Briggs3

1Graduate Program in Biomedical Engineering, UT Southwestern Medical Center, Dallas, TX, USA; 2Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX, USA; 3Department of Radiology, UT Southwestern Medical Center, Dallas, TX, USA; 4Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA

Functional connectivity networks associated with dorsal (DS) and ventral striatum (VS) were studied with BOLD FcMRI. The VS exhibited strong connections with a ventral and medial anterior prefrontal network consistent with its limbic connections. The DS demonstrated strong connections along a more dorsal and lateral prefrontal network. Additionally, the DS demonstrated stronger negative correlation with primary sensory, lateral parietal cortices and superior cuneus than VS. Both the VS and DS exhibited strong connections to the medial dorsal nucleus of the thalamus. Results are highly consistent with previous studies of the anatomical and hypothesized functional connections of these two networks.

14:00         3729.     Modulation of BOLD-Response in the Hypothalamus by Affectively Loaded Visual Stimuli

Florian Gerstl1,2, Christian Windischberger1,2, Karl Ægir Karlsson3, Ewald Moser1,2

1MR Center of Excellence, MUW, Vienna, Austria; 2Center for Biomedical Engineering and Physics, MUW, Vienna, Austria; 3Department of biomedical engineering, School of science and engineering, Reykjavik University, Reykjavik, Iceland

The hypothalamus, which is of pivotal importance for vegetative regulation of the human body, is additionally involved in the mediation of emotional responses. As the first of its kind, this study in 21 healthy volunteers

14:30         3730.     Functional Imaging of Conditioned Nicotine Administration in an Animal Model of ADHD

Wei Chen1, Joseph R. DiFranza2, Wei Huang3, Jean A. King4

1Center for Comparative Neuroimaging,Psychiatry, University of Massachusetts Medical School, Worcester, MA, USA; 2Department of Family Medicine and Community Health, University of Massachusetts Medical School; 3Center for Comparative Neuroimaging,Psychiatry, , University of Massachusetts Medical School, Worcester, MA, USA; 4Center for Comparative Neuroimaging,Psychiatry,, University of Massachusetts Medical School, Worcester, MA, USA

A method for mapping brain activation produced by a conditioned nicotine cue in a genetic model of Attention Deficit Hyperactivity Disorder (ADHD) is described. In this method, rats were conditioned to associate a compartment of a Conditioned Place-Preference (CPP) apparatus to either nicotine or saline. Through the use of awake animals we were able to conduct the first study of drug-reward cue processing using fMRI in an animal model, which makes it available to use fMRI to compare food and drug reward cue processing in humans and in animal addiction models with the addition of molecular studies in the animals.

15:00         3731.     Functional Connectivity to Dorsal and Ventral Striatum Exhibit Different Dependencies on FcMRI Baseline Conditions

Aman Goyal1, Wendy Ringe2, Kaundinya Gopinath3,4, Lei Jiang3, Robert Haley4, Richard Briggs3,4

1Graduate Program in Biomedical Engineering, UT Southwestern Medical Center, Dallas, TX, USA; 2Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX, USA; 3Department of Radiology, UT Southwestern Medical Center, Dallas, TX, USA; 4Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA

Resting state FcMRI networks were examined under 3 baseline conditions: resting eyes open, resting visual fixation and resting eyes open (“Rest”) with concurrent sub-threshold transcutaneous electrical stimulation (“TENS”), to examine the effects of study environment on the networks identified as associated with dorsal and ventral striatum resting fluctuations. Results indicate that “TENS” condition emphasizes connectivity of intention and attention networks to dorsal striatum better than “Rest”, but suppresses the expression of ventral striatal connectivity in ventroanterior prefrontal systems (highlighted clearly in “Rest”). Thus, the choice of the FcMRI baseline condition appears to have profound affects on connectivity.

 
Exhibit Hall 2-3                    Thursday 13:30-15:30          Computer 40

13:30         3732.     Reliability of a Breath-Hold Paradigm to Characterise Inter-Subject Differences in Cognition Based Bold Contrast

Marie Tisserand1, Fernando Zelaya2, Owen O'Daly2, Alejandro Caceres2, Laurence Reed3, Mitul Mehta2

1Department of Neuroradiology, Nancy University Hospital, Nancy, France; 2Centre for Neuroimaging Sciences, Institute of Psychiatry, London, UK; 3Section of Addiction Sciences, Institute of Psychiatry, London, UK

The utility of breath-hold challenges for the characterisation of the vascular contribution to the BOLD response in different subjects, depends on their ability to elicit reliable and reproducible signals across different sessions. The intra-class correlation coefficient (ICC) has been proposed as a means of obtaining a voxel-wise measure of reliability in scans collected at different time points. We generated group-wide ICC maps from 18 subjects who executed a breath-hold challenge in two separate sessions. Maps show remarkably high reliability in grey matter suggesting that these challenges could be used reliably if collected at different time points

14:00         3733.     Test-Retest Reliability Assessment for Longitudinal Studies Spanning a Major MRI System Upgrade

Claudine Gauthier1,2, Cécile Madjar2, Oury Monchi2,3, Julien Doyon2,4, Richard D. Hoge1,2

1Department of Physiology, Université de Montréal, Montreal, Quebec, Canada; 2Unité de Neuroimagerie Fonctionnelle, Institut universitaire de gériatrie de Montréal, Montreal, Quebec, Canada; 3Department of Radiology, Université de Montréal, Canada; 4Department of Psychology, Université de Montréal, Canada

There comes a time in the lifecycle of an MRI research center when major scanner hardware and software upgrades become necessary. Scanner hardware upgrades, while greatly desirable for the increased capabilities they bring, may pose problems for ongoing functional MRI studies. To assess BOLD sensitivity under conditions of high and low SNR, we acquired at two different spatial resolutions (2x2x2mm and 4x4x4mm) with visual stimulation. Overall, results show no significant differences before and after the upgrade. This likely reflects the fact that our experiments were dominated by physiological as opposed to instrumental noise.

14:30         3734.     Concurrent Electromyography Guided FMRI Analysis to Improve Detection and Reduce Inter-Session Variability of the Measured Cortical Response to Ankle Dorsiflexion

Samia Aboushoushah1, Xia Lin2, Richard Bowtell1, Margaret Phillips2, Cris Constantinescu3, Susan Francis1

1School of Physics and Astronomy, University of Nottingham, Nottingham, UK; 2Division of Rehabilitation and ageing, University of Nottingham, Nottingham, UK; 3Division of Clinical Neurology, University of Nottingham, Nottingham, UK

This work assesses the use of electromyography (EMG) guided analysis of fMRI data in the study of the cortical response to ankle dorsiflexion (ADF) movements. The quality of the EMG signal in the MR environment has been assessed, and EMG-guided analysis compared to conventional analysis for the study of active, passive and electrical stimulation induced ADF movements in healthy volunteers. Reproducibility of fMRI responses for each ADF movement were compared across sessions. The methods described serve as proof of principle for the study of cortical changes following a longitudinal course of FES therapy in patients with MS and stroke.

15:00         3735.     Repetition-Related Neural Plasticity: Common Memory Mechanisms in Birds and Humans.

Colline Poirier1, Tiny Boumans2, Marleen Verhoye2,3, Jacques Balthazart4, Annemie Van der Linden2

1Bio-Imaging Lab, Antwerp, Belgium; 2Bio-Imaging Lab, Belgium; 3Vision Lab, Antwerp, Belgium; 4Research Unit in Behavioral Neuroendocrinology, Liège, Belgium

Studies in Biology (specialization in animal behavior), France.

 


 
Myocardial Viability, Function, Perfusion
Exhibit Hall 2-3                    Monday 14:00-16:00          Computer 41

14:00         3736.     Detecting Clinically Significant Subtle Myocardial Damage in Myocardial Infarction Using Multi-Contrast Delayed Enhancement MRI: Correlation with Whole-Mount Heart Histology at Micron-Level Resolution

Yuesong Yang1, Jay S. Detsky1, Mihaela Pop1, Alexander J. Dick1, Graham A. Wright1,2

1Imaging Research, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada; 2Medical Biophysics, University of Toronto, Toronto, Ontario, Canada

Synopsis: It is very challenging to detect clinically significant subtle myocardial damage such as papillary muscle (PM) and right ventricular (RV) involvement associated with myocardial infarction (MI) by conventional MRI. PM-MI is a primary factor leading to the occurrence of mitral regurgitation and a potential source of ventricular arrhythmia. RV-MI and dysfunction are also independent indicators of poor prognosis in patients with MI. In this paper a new multi-contrast delayed enhancement (MCDE) MRI technique is used to identify these subtle myocardial damage and was correlated with whole-mount heart histology at micron-level resolution.

14:30         3737.     Improved Method for Assessing Myocardial Infarction in Rodents at 9.4T Using Delayed Enhancement-MRI

Anthony N. Price1, Kenneth K. Cheung1, Mark F. Lythgoe1

1Centre for Advanced Biomedical Imaging, UCL Institute of Child Health, University College London, London, UK

In the clinical setting delayed enhanced MRI uses inversion recovery sequences to provide the best level of contrast between MI and healthy myocardium. Relatively few studies have reported on their use in small animals, primarily due to the problems associated with rapid heart and respiratory rates, and relatively long T1 recovery times that are exhibited at high fields. In this abstract we report on the implementation of a fast inversion recovery sequence on a 9.4T experimental system for the assessment of myocardial infarction in rats during the hyper-acute phase.

15:00         3738.     Myocardial Infarction Quantification and Function Assessment with Manganese Enhanced MRI (MEMRI) in Mice on a Clinical 3T Scanner

Benedicte Delattre1, Vincent Braunersreuther2, Jean-Noël Hyacinthe1, François Mach2, Jean-Paul Vallée1,3

1Faculty of Medicine, University of Geneva, Geneva, Switzerland; 2Division of Cardiology, Department of Medicine, University Hospital, Foundation for Medical Researchers, Geneva, Switzerland; 3Work supported in part by the Center for Biomedical Imaging (CIBM), Geneva and Lausanne

Manganese contrast agent is an efficient marker of cell activity. It has already revealed a strong efficiency in the assessment of transmural fibrotic scar myocardial infarction in mice model of permanent ligation. We demonstrate the feasibility of accurate infarct volume quantification by Manganese Enhanced MRI (MEMRI) and infarct related function deficit detection in a model of coronary occlusion reperfusion in mice, which leads to non transmural infarction. The protocol was validated on a clinical 3T scanner, a widely available platform.

15:30         3739.     Visualization of Myocardial Inflammation in Experimental Autoimmune Myocarditis Rats Detected by MR Imaging with a Magnetofluorescent Nanoparticles

Hyeyoung Moon1, Hyo Eun Park1, Quan-Yu Cai1, Cheongsoo Park1, Ki-Bae Seung2, Kiyuk Chang2, Kwan Soo Hong1

1Magnetic Resonance Imaging Team, Korea Basic Science Institute, Cheongwon-Gun, Chungcheongbuk-Do, Korea; 2Department of Internal Medicine, Catholic University, Seoul, Korea

In this study, we investigated whether CMR would be feasible and effective for the detecting the inflammation in a rat model of experimental autoimmune myocarditis (EAM) and whether CMR could give a guidance where the biopsy samples should be collected using MNP

 
Exhibit Hall 2-3                    Tuesday 13:30-15:30          Computer 41

13:30         3740.     Hybrid Adiabatic-Rectangular Pulse Train for Effective Saturation of Magnetization Within the Whole Heart at 3T

Daniel Kim1, KellyAnne McGorty1

1Center for Biomedical Imaging and Radiology, NYU Langone Medical Center, New York, NY, USA

While 3T MRI is a promising modality to increase the contrast-to-noise ratio in first-pass cardiac perfusion imaging, increased radio-frequency (RF) variations and dielectric effects make it difficult to perform accurate T1-weighting using a conventional saturation pulse. Previously proposed adiabatic B1-insensitive rotation, rectangular RF pulse train, and tailored rectangular RF pulse train did improve the saturation of magnetization, but none of them achieved effective saturation of magnetization within the whole heart, while remaining within clinically acceptable specific absorption rate limits. The purpose of this study was to develop a hybrid adiabatic-rectangular pulse train that can achieve both of the aforementioned objectives.

14:00         3741.     Oxygen Inhalation Reduces Left Ventricular Perfusion and Cardiac Output Measured by Magnetic Resonance Imaging

Marcus Carlsson1, Stefan Bodetoft2, Hakan Arheden, Ulf Ekelund2

1Lund University Hospital, Dep of Clinical Physiology, Lund, Sweden; 2Dep of Emergency Medicine

Oxygen is administered on a routine basis to patients, however the consequences on the cardiac physiology are not clear. This MR-study used cine steady state free precession images to measure left ventricular dimensions and phase velocity encoded images to measure cardiac output in the aorta and the flow in the coronary sinus to calculate LV perfusion. Oxygen inhalation decreased left ventricular perfusion and cardiac output in healthy volunteers.

14:30         3742.     Cine-EPI Can Be Used to Detect Adenosine-Induced Myocardial Oxygenation Changes in Canines

Jordin Daniel Green1,2, Matthias Voehringer2, Jacqueline A. Flewitt2, Sven Zuehlsdorff3, John Victor Tyberg2, Matthias G. Friedrich2

1Siemens Healthcare, Calgary, Alberta, Canada; 2University of Calgary, Calgary, Alberta, Canada; 3Siemens Medical Solutions USA, Inc., Chicago, IL, USA

The purpose of this study was to demonstrate that BOLD-sensitive cine-EPI with effective TE=15 ms could detect changes in myocardial oxygenation. We developed a cine-EPI sequence and tested it in dogs with varying degrees of coronary artery stenoses, at rest and during adenosine infusion. We detected statistically significant differences in the response to adenosine in myocardial territories affected by high-grade stenoses compared to territories in the same dog unaffected by the high-grade stenoses.

15:00         3743.     Malignant and Benign Cardiac Tumors: Differentiation by MR Perfusion Assessment

Kerstin Ulrike Bauner1, Steven Sourbron1, Michael Schmoeckel2, Maximilian F. Reiser1, Armin M. Huber1

1Department of Clinical Radiology, University of Munich; Grosshadern hospitals, Munich, Germany; 2Department of Cardiac Surgery, University of Munich; Grosshadern Hospitals

Semiquantitative analysis of first pass perfusion may contribute additional information to tumor characterization. The aim of the study therefore was to determine, whether dynamic contrast material-enhanced magnetic resonance (MR) imaging with use of kinetic parameters reveals statistically significant differences between benign and malignant cardiac tumors. The calculated contrast enhancement ratios (CER %), the maximum slope of the contrast enhancement ratio curve (% / sec) and the area under the contrast enhancement ratio curve (% * sec) resulted in significantly higher values for malignant cardiac lesions in comparison to benign lesions.

 
Exhibit Hall 2-3                    Wednesday 13:30-15:30          Computer 41

13:30         3744.     The Athlete's Heart - Gender Aspects

Katarina Steding1, Torsten Buhre2, Björn Wohlfart1, Henrik Engblom1, Henrik Mosén1, Bo Hedén1, Håkan Arheden1

1Clinical Physiology, Institution for Clinical Sciences, Lund, Sweden; 2Institution for Sport Sciences, Malmö, Sweden

Few studies of the effect of training on cardiac dimensions include females. The aim of the study was to investigate if the morphological response to training differs between males and females. 71 athletes underwent cardiac magnetic resonance imaging and total heart volume (THV), left ventricular mass (LVM) and left- and right end diastolic volume (LVEDV, RVEDV) was calculated. Training increased THV, LVEDV and RVEDV in the same order of magnitude in males and females. Differences in THV/BSA may be diminished when females engage in high frequencies of long-term endurance training. The LVM/THV, however, remain significantly higher in males.

14:00         3745.     Feasibility of Real-Time Cine to Detect Exercise-Induced Cardiac Wall Motion Abnormalities in Patients Suspected of Coronary Artery Disease

Mihaela Jekic1, Jennifer Dickerson2, Eric Foster3, Beth McCarthy2, Subha V. Raman2, Orlando P. Simonetti4

1Biomedical Engineering, The Ohio State University, Columbus, OH, USA; 2The Ohio State University Medical Center; 3Mechanical Engineering, The Ohio State University; 4Internal Medicine and Radiology, The Ohio State University

We investigated whether real-time non-breathhold cine with TGRAPPA rate 3 acceleration, temporal resolution of 62 ms, and spatial resolution of 3.8x2.5x8mm can detect regional wall motion abnormalities at peak exercise stress. We performed a blinded review of five patients suspected of coronary artery disease and five healthy subjects. Images from all five healthy volunteers and three patients with <70% stenoses were correctly interpreted as normal. Two patients with >70% lesions were diagnosed with wall motion abnormalities. Our results indicate that it is feasible to detect exercise-induced regional wall motion abnormalities using real-time non-breath-hold cine.

14:30         3746    Feature Tracking of Cine MRI Images Identifies Left Ventricular Segments with Transmural Myocardial Scar

Eva Maret1,2, P-G Bjorklund3, B-M Ahlander3, Johan Kihlberg4, Jan Ohlsson1, Eva Swahn5, Tim Todt5, Jan Engvall4,6

1Dpt of Clinical Physiology, Ryhov County Hospital, Jonkoping, Sweden; 2CMIV, Linkoping University Hospital , Linkoping, Sweden; 3Dpt of Radiology, Ryhov County Hospital, Jonkoping, Sweden; 4CMIV, Linkoping University Hospital, Linkoping, Sweden; 5Dpt of Cardiology, Linkoping University Hospital, Linkoping, Sweden; 6Dpt of Clinical Physiology, Linkoping University Hospital, Linkoping, Sweden

After myocardial infarction, treatment aims at restoring normal cardiac function, which is more likely if scar transmurality is limited. Cardiac wall motion is complex and difficult to objectively analyze. We have used a feature tracking software to measure radial and longitudinal velocity, displacement and strain to evaluate scar segments in patients after ST-elevation myocardial infarction. The method could separate segments with various scar transmurality as determined with gadolinium enhancement.

15:00         3747.     Quantification of Global Hypokinesis in Left Ventricle Using Center Point Trajectory (CPT) Mapping

Ting Song1, Jeffrey A. Stainsby2, Maureen N. Hood3, Vincent B. Ho4

1Applied Science Laboratory, GE Healthcare, Bethesda, MD, USA; 2Applied Science Laboratory, GE Healthcare, Toronto, ON, Canada; 3Radiology, Uniformed Services University of the Health Sciences and National Naval Medical Center, Bethesda, MD, USA; 4Radiology, Uniformed Services University of the Health Sciences and National Naval Medical Center, Bethesda, Bethesda, MD

The identification and quantification of diffuse or global left ventricular (LV) hypokinesis is problematic. We investigate the feasibility of a novel technique called Center Point Trajectory (CPT) mapping that provides not only an improved method for identification of global hypokinesis but also a method for quantitatively characterizing diffuse left ventricular dysfunction. CPT mapping has an advantage in instances where the myocardial wall is thin, which is not uncommon in patients with underlying ischemic heart disease and heart failure.

 
Exhibit Hall 2-3                    Thursday 13:30-15:30          Computer 41

13:30         3748.     An Intensity Based Statistical Approach for Left Ventricular Localization and Identification of End-Systolic and End-Diastolic Images from Cine Cardiac MRI

Sotirios Athanasios Tsaftaris1, Xiangzhi Zhou2, Richard Tang2, Rachel Klein2, Rohan Dharmakumar2

1Electrical Engineering and Computer Science, Northwestern University, Evanston, IL, USA; 2Radiology, Northwestern University, Chicago, IL, USA

A critical component in computing quantitative diagnostic metrics, such as ejection fraction, as well as image segmentation and registration, is the accurate identification of the end-systolic (ES) and end-diastolic (ED) frames in cine MRI. Localization of the LV is also important, to assist further analysis (ie., myocardial segmentation). In this paper we propose an image-driven statistical method that utilizes cross-correlation of pixels, to detect ES and ED images, as well as, localize the LV, from cine MRI acquired from canines under control conditions. The method is fully automated, computationally efficient, and requires no parameterization, initialization, and ROI selection.robust, and can be extended to 4D MRI.

14:00         3749.     Automatic Computation of Ejection Fraction Using Temporal Intensity Information

Amol Pednekar1, Mercedes Pereyra2, Brenda Lambert3, Debra Dees2, Benjamin Cheong2,4, Raja Muthupillai, 2,5

1Philips Healthcare, Houston, TX, USA; 2Department of Radiology, St.Luke’s Episcopal Hospital and Texas Heart Institute, Houston, TX, USA; 3Department of Radiology,, St.Luke’s Episcopal Hospital and Texas Heart Institute, Houston, TX, USA; 4Department of Cardiology4, St.Luke’s Episcopal Hospital and Texas Heart Institute, Houston, TX, USA; 5Department of Radiology, Baylor College of Medicine, Houston, TX, USA

Manually delineation of the endocardial contours to compute left ventricular (LV) volumes and ejection fraction (EF) from cine-magnetic resonance images is labor intensive, and operator dependent. We clinically validated an automatic algorithm that computes the LVEF using classification of partial volumed pixels based on temporal intensity information in conjunction with geometrically smooth parametric curve on 16 volunteers (LVEF mean 58%, range 49-70%) and 7 patients (LVEF mean 53%, range 40-65%). The mean bias values computed with Bland-Altman analysis (EF-2%, EDV-2ml, ESV-4ml) between automated contours and expert manual contours is comparable to the typical inter- and intra-observer variability of experienced clinicians.

14:30         3750.     Automated Recognition of Abnormal Left Ventricle Wall Motion

YingLi Lu1, Perry Radau1, Kim A. Connelly1,2, Alexander Dick3, Graham A. Wright1

1Imaging Research, Sunnybrook Health Sciences Centre, Toronto, ON, Canada; 2Cardiology,  St Michael's Hospital, Toronto, ON, Canada; 3Cardiology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada

We propose an algorithm for automated detection of hypokinetic cardiac wall motion from cine cardiac MR that includes inter-subject normalization and a pattern recognition technique. The recognition algorithm consists of three stages: 1) normalizing the left ventricle (LV) size, shape, intensity, and position, 2) extracting features called intra-segment correlation coefficients from the normalized LV images, and 3) discriminating normal and hypokinetic wall motion. Application of the algorithm on 17 patient datasets resulted in accuracy, sensitivity and specificity of 83.3%, 93.6% and 78.9% respectively. These preliminary results demonstrated a promising method for automated recognition of hypokinetic LV wall motion.

15:00         3751.     Polar-Regularized Left Ventricular Strain Analysis from Cine MRI Using Non-Rigid Registration

Wei Feng1, Himanshu Gupta2, Steven G. Lloyd2, Louis J. Dell'Italia2, Thomas S. Denney Jr. 1

1Electrical and Computer Engineering, Auburn University, Auburn University, AL, USA; 2University of Alabama at Birmingham

A method called cine myocardial deformation analysis (CMDA) is proposed for computing 2D left ventricular (LV) myocardium strain from cine MR images. CMDA uses non-rigid registration and incorporates contour regularization and polar regularization of a B-spline deformation model. CMDA was validated over 20 normal human volunteers and 20 patients with myocardial infarction. CMDA circumferential strain showed excellent agreement with strains computed from tagged MR images using HARP and a 3D model-based method. While tagged and DENSE MRI will continue to be gold standards for measuring LV strain, LV strain can be accurately measured from cine MR cardiac images using CMDA.

 


 
Myocardial Tissue Characterization:  Fat, Hemorrhage & Edema
Exhibit Hall 2-3                    Monday 14:00-16:00          Computer 42

14:00         3752.     Quantitative MRI in the Detection of Cardiac Iron in Patients with Thalassemia

Jin Yamamura1, Regine Grosse, Rainer Engelhardt, Joachim Graessner2, Gregory Kurio3, Roland Fischer3, Gritta E. Janka, Gerhard Adam1

1Diagnostic and Interventional Radiology, University Hospital Hamburg-Eppendorf, Hamburg, Germany; 2Siemens AG; 3Children’s Hospital & Research Center, Oakland, USA

Cardiac iron concentration in patients with iron overload can be determined from multiple gradient recalled echo measurements (MRI-R2*) within one breathhold, although there are technical limitations with respect to echo times and analysis methods. These limitations may be less important for diagnosis than for monitoring cardiac iron overload. In a cross-sectional study, R2* in the heart in those being at risk of developing problems from cardiac iron toxicity, i.e. patients with Thalassemia, were examined with optimized methods. The measurement of MRI-R2* in the ventricular septum can detect patients with iron overload at risk of developing heart failure from cardiac iron toxicity due to chronic blood transfusions. Early detection may induce intensive iron chelation with the benefit of avoiding heart failure.

14:30         3753.     Heart and Liver R2 and R2* Measurements in Patients with Thalassaemia Major at 3T

Hua Guo1,2, Wing-Yan Au3, Jerry S. Cheung1,2, Jens H. Jensen4, Daniel Kim4, Pek-Lan Khong5, Queenie Chan6, Christina Tosti7, Haiying Tang7, Truman R. Brown7, Wynnie W.M. Lam8, Shau-Yin Ha9, Gary M. Brittenham10, Ed X. Wu1,2

1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong, China; 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China; 3Department of Medicine, The University of Hong Kong, Hong Kong; 4Department of Radiology, New York University School of Medicine, New York, USA; 5Department of Diagnostic Radiology, The University of Hong Kong, Hong Kong; 6Philips Electronics Hong Kong Limited; 7Radiology, Columbia University College of Physicians and Surgeons, New York, USA; 8Department of Diagnostic Radiology and Organ Imaging, Chinese University of Hong Kong, Hong Kong; 9Pediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong; 10Department of Pediatrics and Medicine, Columbia University College of Physicians and Surgeons, New York, USA

To determine the feasibility of measurements of transverse relaxation times for assessment of tissue iron overload at high field, we compared results of determinations of R2 and R2* using breathhold multi-echo spin-echo (MESE) and multi-echo gradient echo (MEGE) sequences, respectively, at 3T and at 1.5T in normal subjects and patients with thalassaemia major. Our results, the first reported measurements of R2 at both 3T and 1.5T in iron overloaded patients, demonstrate significant correlations in heart and liver at the two field strengths. These results provide evidence that myocardial and hepatic R2 can be measured at 3T as indicators of iron overload.

15:00         3754.     Multi-Centre Validation of the Magnetic Resonance T2* Technique for Segmental and Global Quantification of Myocardial Iron

Vincenzo Positano1, Anna Ramazzotti1, Alessia Pepe1, Giuseppe Rossi1, Cristina Salvatori2, Antonella Meloni1, Daniele De Marchi1, Brunella Favilli1, Luigi Natale3, Eliana Cracolici4, Gennaro Restaino5, Gianluca Valeri6, Antongiulio Luciani7, Luigi Landini1, Massimo Lombardi1

1MRI Laboratory, "G Monasterio" Foundation and Institute of Clinical Physiology, Pisa, Italy; 2MRI Laboratory, "G Monasterio" Foundation and Institute of Clinical Physiology, Italy; 3Policlinico Gemelli, Roma, Italy; 4Policlinico "P. Giaccone", Palermo, Italy; 5Università Cattolica del Sacro Cuore, Campobasso, Italy; 6Ospedali Riuniti di Ancona, Ancona, Italy; 7Az. Ospedaliera "G. Garibaldi", Catania, Italy

The transferability of the MRI multislice multiecho T2* technique accounting for segmental and global myocardial iron distribution was assessed among six sites

15:30         3755.     R2 Imaging of Ferritin Iron in Thalassemic Patients Off and on Iron-Chelation Therapy

Daniel Kim1, Jens H. Jensen1, Christina L. Tosti2, Ed X. Wu3, Sujit S. Sheth4, Truman R. Brown5, Gary M. Brittenham4

1Center for Biomedical Imaging and Radiology, NYU Langone Medical Center, New York, NY, USA; 2Bioengineering, Columbia University, New York, NY, USA; 3Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong; 4Pediatrics and Medicine, Columbia University College of Physicians and Surgeons, New York, NY, USA; 5Radiology and Bioengineering, University College of Physicians and Surgeons, New York, NY, USA

Accurate assessment of iron burden is crucial for the management of iron-chelation therapy. MRI provides a means to non-invasively assess tissue iron concentration by exploiting the paramagnetic effects of iron on the relaxation rates of solvent protons. The most widely used method is R2* imaging, which has been shown to be sensitive to myocardial iron overload. Recently, a breath-hold fast spin echo sequence has been proposed for fast and accurate imaging of myocardial and hepatic R2. The purpose of this study was to determine which relaxation rates are sensitive to iron-chelation therapy.

 
Exhibit Hall 2-3                    Tuesday 13:30-15:30          Computer 42

13:30         3756.     Single-Breathhold Myocardial T2 and T2* Quantification in Normal Volunteer Subjects at 3T

Hua Guo1,2, Jerry S. Cheung1,2, Daniel Kim3, Pek-Lan Khong4, Gary M. Brittenham5, Ed X. Wu1,2

1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong, China; 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China; 3Department of Radiology, New York University School of Medicine, New York, USA; 4Department of Diagnostic Radiology, The University of Hong Kong, Hong Kong; 5Department of Pediatrics and Medicine, Columbia University College of Physicians and Surgeons, New York, USA

Increased B0 and B1 inhomogeneity, together with increased motion artifacts, present challenges for cardiac imaging and quantitation at 3T. This study measured myocardial T2 in normal subjects at 3T using a novel single-breathhold black-blood hybrid TSE/MESE T2 measurement protocol. The average myocardial T2 was found to be 39.6±7.4ms, with peak-to-peak variations of the measured T2 values < 5%. The results demonstrate the feasibility of myocardial T2 quantitation at 3T.

14:00         3757.     Is Hemorrhage in Acute Reperfused Myocardial Infarction a New Marker for the Severity of Tissue Injury?

Andreas Kumar1, Jordin D. Green1,2, Jane M. Sykes3, Andrea J. Mitchell3, Gerald Wisenberg3, Matthias G. Friedrich1

1Stephenson CMR Centre, University of Calgary, Calgary, AB, Canada; 2Siemens Canada Ltd, Calgary, AB, Canada; 3Lawson Health Research Institute, University of Western Ontario, London, ON, Canada

We applied a T2*-weighted cardiovascular magnetic imaging sequence to assess the effect of hemorrhage in reperfusion injury in acute myocardial infarction. In this dog model, hemorrhage was associated with larger infarct size and worse functional parameters.

14:30         3758.     Assessment of Cardiac Iron and Right Ventricular  Function by GRE-MRI in Patients with Thalassemia and Sickle Cell Disease

Jin Yamamura1, Regine Grosse, Rainer Engelhardt, Joachim Graessner2, Gregory Kurio3, Roland Fischer3, Gritta E. Janka, Gerhard Adam1

1Diagnostic and Interventional Radiology, University Hospital Hamburg-Eppendorf, Hamburg, Germany; 2Siemens AG; 3Children’s Hospital & Research Center, Oakland, USA

Elevated or normal cardiac iron load with preserved LV function is often seen in patients with beta-thalassemia major, intermedia, and sickle cell disease. Cardiac iron concentration and LV function can be measured by established quantitative MR methods; still the right ventricular dysfunction caused by pulmonary hypertension may become the leading factor of heart failure. The aim of this study was to evaluate the RV function and the cardiac iron in patients with thalassaemia and sickle cell disease.

15:00         3759.     Visualizing and Quantifying Myocardial Oxygenation Changes with Statistically Optimal Colormaps

Sotirios Athanasios Tsaftaris1, Richard Tang2, Rachel Klein2, Debiao Li2,3, Rohan Dharmakumar2

1Electrical Engineering and Computer Science, Northwestern University, Evanston, IL, USA; 2Radiology, Northwestern University, Chicago, IL, USA; 3Biomedical Engineering, Northwestern University, Evanston, IL, USA

A method for automatic visualization and quantification of myocardial signal changes reflecting the regional variations in microcirculatory oxygenation is presented. The objective of this study is to overcome the subjective step of windowing by establishing an optimal colormap that permits visualization of statistical changes in signal intensities between healthy and pathological cases. In addition, graph theory is used to derive a quantitative metric of myocardial oxygenation. Although further studies are necessary, this initial work provides a new direction in the evaluation of BOLD images for detection of myocardial oxygenation impairments resulting from coronary artery stenosis.

 
Exhibit Hall 2-3                    Wednesday 13:30-15:30          Computer 42

13:30         3760.     Optimization and Validation of a Modified Look-Locker Saturation-Recovery (MLLSR) Sequence Applied to Cardiac T1 Mapping

Ting Song1, Maureen N. Hood2, Vincent B. Ho3, Sandeep N. Gupta4, Jeffrey A. Stainsby5

1Applied Science Laboratory, GE Healthcare, Bethesda, MD, USA; 2Radiology, Uniformed Services University of the Health Sciences and National Naval Medical Center, Bethesda, MD, USA; 3Radiology, Uniformed Services University of the Health Sciences and National Naval Medical Center, Bethesda, Bethesda, MD; 4GE Global Research, Niskayuna, NY, USA; 5Applied Science Laboratory, GE Healthcare, Toronto, ON, Canada

Cardiac T1 mapping is a challenging problem given cardiac motion and respiratory motion. A modified look-locker saturation-recovery (MLLSR) sequence was evaluated on both phantoms and human studies in this paper. Saturation recovery has benefits over inversion recovery methods in quantification of T1 as it obviates the need for dummy heartbeats used for relaxation to equilibrium, and fitting of the data is not confounded by the phase of the MR signal. The MLLSR T1-mapping sequence is shown to be robust for cardiac applications across a range of flip angles and heart rates, across a wide range of T1 relaxation times.

14:00         3761.     Myocardial Fat Quantification Using Two-Point Water-Fat Imaging with Simultaneous T2* Correction

Chia-Ying Liu1, Alban Redheuil1, Ronald Ouwerkerk1, Joao Lima1, David Bluemke2

1Department of Radiology, Johns Hopkins Hospital, Baltimore, MD, USA; 2Radiology and Imaging Sciences, National Institutes of Health, Bethesda, MD, USA

The concept of fat contained within the myocardium, has recently received attention because of its potential role in diabetic myocardial disease, obesity, and HIV infected individuals. Measurements of myocardial triglycerides in humans have been accessed using proton MR spectroscopy (1H MRS). We studied whether the dual-echo Dixon MRI could quantify the fatty content of the myocardium on normal volunteers. The bias including T1, T2*, and noise that confound the calculation of the fat fraction were carefully corrected. The fraction of fat was also quantified directly with 1H MRS as an independent method.

14:30         3762.     Myocardial Fibro-Fatty Infiltration in Duchenne Muscular Dystrophy Canine Model Detected Using Multi-Echo Dixon Method of Water and Fat Separation Imaging

Peter Kellman1, Diego Hernando2, Saurabh Shah3, Robert F. Hoyt, Jr. 1, Robert M. Kotin1, Bruce W. Keene4, Joe N. Kornegay5, Anthony H. Aletras1, Andrew E. Arai1

1National Institutes of Health, Bethesda, MD, USA; 2University of Illinois, Urbana, IL, USA; 3Siemens Medical Solutions, Chicago, IL, USA; 4College of Veterinary Medicine, North Carolina State University, NC, USA; 5School of Medicine, University of North Carolina, Chapel Hill, NC, USA

Cardiac magnetic resonance using a multi-echo Dixon fat and water separation method was used to image fibro-fatty infiltration in the myocardium in dogs with Duchenne Muscular Dystrophy. Inducibility of arrhythmias in patients with DMD has been reported to correlate with fatty infiltration. The multi-echo Dixon method for fat and water separation provides a sensitive means of detecting small concentrations of fat with improved contrast.

15:00         3763.     Myocardial Lipid Accumulation Due to High Fat Diet in PPAR-Alpha Overexpressing Mouse Hearts Reduces Endocardial 2-D Principal Strains

Janusz H. Hankiewicz1, Natasha H. Banke1, E. Douglas Lewandowski1

1Program in Integrative Cardiac Metabolism, UIC College of Medicine, Chicago, IL, USA

Myocardial lipid content and 2D strains in the epi- and endocardium of the LV were determined, over a two week period of high fat diet, in non-transgenic mice (NTG) and a transgenic mouse model of increased myocardial lipid due to cardiac-specific overexpression of the proxisome proliferators activated nuclear receptor α (PPAR α). High-resolution cardiac tagging revealed that high fat diet reduced endocardial E1 and E2 strains in PPAR α hearts, while 1H MRS showed a 130% greater lipid content in than NTG hearts. Close correlations between lipid content and 2D strains indicate increased myocardial stiffness is a consequence of elevated myocardial lipid.

 
Exhibit Hall 2-3                    Thursday 13:30-15:30          Computer 42

13:30         3764.     The Accuracy of Myocardial T2-Mapping Techniques

Shivraman Giri1, Georgeta Mihai1, Yiu-Cho Chung2, Orlando P. Simonetti1

1The Ohio State University, Columbus, OH, USA; 2Siemens Medical Solutions USA, Inc., Columbus, OH, USA

In this study, we investigate 4 different protocols using 2 pulse sequences in terms of their accuracy to determine T2 of phantoms. Using the best of these protocols, we propose an accurate and practical approach to generating T2 maps of human myocardium that can be used in a clinical setting. We then use this technique to get a range of human myocardial T2 values.

14:00         3765.     An Accurate and Quantitative T2 Mapping Technique to Detect Myocardial Edema in Acute Coronary Syndrome

Shivraman Giri1, Georgeta Mihai1, Ali Merchant1, Xiaoming Bi2, Yiu-Cho Chung3, Tam Tran1, Subha V. Raman1, Orlando P. Simonetti1

1The Ohio State University, Columbus, OH, USA; 2Siemens Medical Solutions USA, Inc, Chicago, IL, USA; 3Siemens Medical Solutions USA, Inc., Columbus, OH, USA

In this study, we use an accurate and practical T2 Mapping technique to address some of shortcomings of T2-Weighted imaging to detect myocardial edema associated with acute coronary syndrome. This T2 mapping technique is shown to be insensitive to surface coil intensity variations and stagnant blood pool artifact and quantitatively differentiates regions of enhanced T2. Results with porcine models and patients are presented.

14:30         3766.     Diffusion Spectrum MRI Tractography Reveals the Presence of a Complex Network of Residual Myofibers Within Infarcted Myocardium.

David Sosnovik1, Ruopeng Wang2, Guangping Dai2, Teresa Wang3, Elena Aikawa, Mikhail Novikov4, Anthony Rosenzweig4, Richard Gilbert3, Van Wedeen2

1Martinos Center for Biomedical Imaging, Massachusetts General Hospital,Harvard Medical School, Boston, MA, USA; 2Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School; 3Massachusetts Institute of Technology; 4Beth Israel Deaconess Medical Center, Harvard Medical School

We describe in this paper the performance of diffusion spectrum MRI tractography in the myocardium. The technique is used to characterize myofiber architecture in normal as well as infarcted rat hearts. A newly described pattern of orthogonal myofibers is detected in infarcted myocardium, and is of significant relevance to both mechanical and electrical remodelling of the infarcted heart.

15:00         3767.     Evaluation of Acute Myocardial Ischemia Gene Therapy Efficacy Using Diffusion Tensor Imaging

Osama M. Abdullah1, James W. Yockman2, CATHERINE M. Straub3, N Hu3, A Albinil4, S W. Kim4, David A. Bull3, Edward W. Hsu1

1Department of Bioengineering, University of Utah, Salt Lake City, UT, USA; 2Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, UT, USA; 3Department of Surgery, University of Utah, Salt Lake City, UT, USA; 4Yonsei University, Seoul

Coronary heart disease is the main cause of ventricular systolic dysfunction and subsequent heart failure. Evaluation of the efficacy of therapeutic interventions for restoring cardiac function necessitates noninvasive techniques to characterize the cellular remodeling. The goal of the current study is to assess the utility of diffusion tensor imaging for evaluating the cellular remodeling, hence the treatment efficacy, in the post-infarct regenerating myocardium. Results show that while myocardial infarct caused a reduction of the water diffusion anisotropy, gene therapy resulted in partial but significant recovery of the diffusion anisotropy, which likely reflect cellular remodeling of the regenerating myocardium.

 


 
Myocardial Perfusion, Diffusion & Spectroscopy
Exhibit Hall 2-3                    Monday 14:00-16:00          Computer 43

14:00         3768.     Spatio-Temporal Modeling of First-Pass Perfusion Cardiovascular MRI

Volker J. Schmid1, Guang-Zhong Yang1

1Institute of Biomedical Engineering, Imperial College, London, UK

Myocardial perfusion MRI provides valuable insight into how coronary artery and microvascular diseases affect myocardial tissue. Stenosis in a coronary vessel leads to reduced maximum blood flow (MBF), but collaterals may secure the blood supply of the myocardium but with altered tracer kinetics. To date, quantitative analysis of myocardial perfusion MRI has only been performed on a local level, largely ignoring the contextual information inherent in different myocardial segments. We propose a Hierarchical Bayesian Model (HBM) to quantify the dependencies between local kinetic systems for perfusion quantification. In the proposed framework, all local systems are modelled simultaneously along with their dependencies, thus allowing more robust context-driven estimation of local kinetics. Validation on both simulated and patient data is provided.

14:30         3769.     Automated Myocardial Segmentation for Quantitative Analysis of First-Pass Cardiac Perfusion MRI

Qi Duan1, Ricardo Otazo1, Daniel Kim1, Daniel K. Sodickson1

1Radiology, Center for Biomedical Imaging, NYU School of Medicine, New York, NY, USA

This abstract presents a fast automated segmentation of cardiac contours for quantitative analysis of first-pass cardiac perfusion MRI. The segmentation method was based on a previously developed novel segmentation framework for real-time segmentation, with an extension to vector images with multi-object segmentation. The myocardial segmentation and the resulting signal-time curves were in good agreement with those produced by manual tracing. The proposed method only takes 31ms to segment the myocardium from the multi-repetition data set.

15:00         3770.     A Parametric Model for Quantitative Analysis of Contrast-Enhanced First-Pass MR Myocardial Perfusion That Accounts for Gd-DTPA Interstitial Loading

Li-Yueh Hsu1, Daniel W. Groves1, Anthony H. Aletras1, Peter Kellman1, Andrew E. Arai1

1National Institutes of Health, Bethesda, MD, USA

Myocardial blood flow of first-pass MR perfusion was estimated using a simple mathematic model in constrained devolution that accounts for loading of the interstitial space with gadolinium contrast. The results of the MR perfusion estimates correlated with a wide range of absolute blood flow measured from microsphere references.

15:30         3771.     Coregistration and Visualization of Regionally Perfused Myocardium from First-Pass Multislice Sets Based on Independent Components Analysis

Ahmet E. Sonmez1, Julien Milles2, Zhigang Deng1, Nikolaos V. Tsekos1

1Computer Science, University of Houston, Houston, TX, USA; 2Radiology, Leiden University Medical Center, Leiden, Netherlands

The aim of this work is to implement an approach for the visualization of regional myocardial perfusion from first pass sets. The method uses Independent Component Analysis to automatically correct for breathing motion among the different time frames of the same slice, thereby allowing the generation of perfusion maps and their reconstruction in a 3D volume. This approach was tested on dynamic cardiac MR images collected during intracoronary infusion of Gd-based contrast agent on pigs. The ICA efficiently co-registered the different frames allowing the generation of 3D regional perfusion map.

 
Exhibit Hall 2-3                    Tuesday 13:30-15:30          Computer 43

13:30         3772.     In Vivo Cardiac NMR Diffusion Weighted Imaging(DWI) for the Human Heart: Improved Quantification of FA and MD by Edge-Preserving Regularization

Carole Frindel1, Stanislas Rapacchi1, Marc Robini1, Han Wen2, Magalie Viallon3, Laurent Fanton4, Pierre Croisille5

1Creatis-LRMN, Université Lyon 1, INSA Lyon, Lyon, France; 2National Heart, Lung and Blood Institute, NIH, Bethesda, MD, USA; 3Hopital Cantonal Universitaire de Genève, Genève, Switzerland; 4Institut de Médecine Légale, Université Lyon 1, Lyon, France; 5Hopital Cardiologique et Pneumologique L. Pradel, Lyon, France

Diffusion weighted imaging in the heart is greatly affected by contractile motion and remains challenging to date. Accurate diffusion measurements require high diffusion encoding gradients and longer echo time that decrease signal strength and thus reduce significantly image quality. This results in diffusion weighted (DW) images corrupted by high level noise, which propagates to parameters computed from the diffusion tensor (e.g. fractional anisotropy, mean diffusivity). To overcome this drawback, we propose to perform edge-preserving regularization on the DW images.

14:00         3773.     Right Ventricular Three-Dimensional Architecture, Assessed with DTMRI, Is Preserved During Experimentally Induced Right Ventricular Hypertrophy

Eva Amalie Nielsen1, Morten Smerup1, Peter Agger1, Jesper Frandsen2, Michael Pedersen3, Steffen Ringgaard3, Peter Vestergaard2, Jens Randel Nyengaard4, Johnnie Bremholm Andersen4, Paul P. Lunkenheimer5, Robert H. Anderson6, Vibeke Hjortdal1

1Department of Cardiothoracic & Vascular Surgery, Aarhus University Hospital, Skejby, Aarhus, Denmark; 2Center for Functionally Integrative Neuroscience, Aarhus University Hospital, Aarhus Sygehus, Aarhus, Denmark; 3MR Research Center, Aarhus University Hospital, Skejby, Aarhus, Denmark; 4Stereology and EM Laboratory and MIND Center, Aarhus University, Aarhus, Denmark; 5Klinik und Poliklinik für Thorax-, Herz- und Gefässchirurgie, University Münster, Münster, Germany; 6Cardiac Unit, Institute of Child Health, University College,, London, UK

The three-dimensional architecture of the myocytes aggregated together making up the right ventricular myocardium (RV) is a major determinant of function. We studied the normal architecture with the arrangement induced by chronic hypertrophy, using diffusion tensor MRI. The architecture is comparable to that found in the left ventricle in terms of endocardial and epicardial angulations of the chains of aggregated myocytes, albeit that the RV lacks the extensive zone of myocytes aggregated in circular fashion in the mid-portion of the left ventricular walls. Without such beneficial architectural remodeling, the porcine RV seems unsuited structurally to sustain a permanent increase in afterload.

14:30         3774.     In Vivo Murine Cardiac PCr and ATP Concentrations Measured by Magnetic Resonance Imaging and Spectroscopy

ashish gupta1, V. P. Chacko2, Robert G. Weiss

11Department of Medicine, Division of Cardiology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; 2Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA

An in vivo 1H MRI and 31P MR spectroscopic method is proposed and validated for the measurement of in vivo high energy phosphate metabolite (PCr and ATP) concentrations in normal (n=7) and thoracic aorta constriction (TAC) (n=10) mouse hearts. The in vivo MR results for [ATP] are in good agreement with those obtained using an in vitro luminescent assay on perchloric acid extracts of the same hearts.

15:00         3775.     Early Diagnosis of Myocardial Infarction Areas on Rat Models Using 2D 31P CSI

Ziqi Sun1, Tiansheng Wang1, Guanglong He1, Jay L. Zweier1

1Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA

Sensitivity-enhanced 2D 31P CSI was applied for early diagnosis of the risk areas in the acute ischemic rat heart. Longitudinal measurements of the PCr-to-ATP ratio in the LAD occluded rat heart showed that the myocardial viability decreased from the peripheral to the central areas of the injured rat heart. This result was further confirmed by the SPIO contrast enhanced MRI. The study indicated that early and accurate diagnosis of myocardium at risk during acute ischemia is possible using sensitivity-enhanced 2D 31P CSI techniques.

 
Exhibit Hall 2-3                    Wednesday 13:30-15:30          Computer 43

13:30         3776.     Cardiac Phase-Resolved 3D SSFP Myocardial BOLD Imaging in Canines with Coronary Artery Stenosis

Xiangzhi Zhou1, Sven Zuehlsdorff2, Saurabh Shah2, Richard Tang1, Rachel Klein1, Debiao Li1, Rohan Dharmakumar1

1Department of Radiology, Northwestern University, Chicago, IL, USA; 2Siemens MED US, Chicago, IL, USA

Myocardial BOLD imaging may be a useful method for evaluating the microcirculatory oxygenation changes resulting from coronary artery stenosis. This work investigates the utility of 3D cine SSFP BOLD imaging for identifying regional myocardial oxygenation changes throughout the left ventricle using a canine model with controllable coronary stenosis. The findings from this study show that 3D SSFP BOLD imaging may be a viable method for assessing regional changes in myocardial oxygenation within the left ventricle. Additional technical improvements are likely necessary to fully explore the benefits of 3D SSFP imaging in the clinical environment.

14:00         3777.     Quantification of Myocardial Oxygen Consumption Rate: Initial Experience in Humans

Kyle Stephan McCommis1, Donna Lesniak1, Thomas A. Goldstein1, Pamela K. Woodard1, Robert J. Gropler1, Jie Zheng1

1Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO, USA

A cardiac MR method is demonstrated to quantify the myocardial oxygen consumption rate at rest and during hyperemia, by using the Fick’s principle. MRI data acquisitions were performed in normal volunteers. Each study session consisted of imaging at rest and adenosine-induced vasodilation. Myocardial oxygen consumption rose proportionally with rate-pressure product from the rest condition. Myocardial blood flow correlated well with oxygen consumption at rest, but mismatched during the vasodilation.

14:30         3778.     T2 Preparation Methods for the Quantification of Myocardial Oxygenation at Rest and During Hyperemia

Kyle Stephan McCommis1, Robert O'Conner1, Dana R. Abendschein2, Bernd Misselwitz3, Robert J. Gropler1, Jie Zheng1

1Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO, USA; 2Cardiovascular Division, Washington University School of Medicine, St. Louis, MO, USA; 3Bayer Schering Pharma AG, Berlin, Germany

A new T2 preparation sequence was developed to calculate myocardial oxygenation at rest and during pharmacologic hyperemia. Imaging was performed in normal dogs, as well as dogs with severe coronary stenosis. Myocardial oxygen extraction fraction and oxygen consumption were measured using these techniques and the results were compared with the established turbo-spin-echo method. Consistent findings were observed and the sensitivity of the oxygenation measurement was significantly improved using the new sequence, likely due to fewer flow artifacts.

15:00         3779.     Dependence of Myocardial BOLD Contrast on Imaging Parameters at 1.5T: Monte Carlo Simulation and Experiments

Xiangzhi Zhou1, Richard Tang1, Rachel Klein1, Debiao Li1, Rohan Dharmakumar1

1Department of Radiology, Northwestern University, Chicago, IL, USA

The effect of TR and flip angle on SSFP based myocardial BOLD sensitivity was studied using a theoretical model which incorporated diffusion effects through Monte-Carlo simulation. Theoretical results were validated using an aniSynopsisth controllable coronary artery stenosis. Both simulations and experimental findings show that SSFP-based myocardial BOLD contrast is directly dependent on TR and flip angle at 1.5T.

 
Exhibit Hall 2-3                    Thursday 13:30-15:30          Computer 43

13:30         3780.     Use of Susceptibility Mapping to Detect Suspicious Dark Rim Artefacts During Perfusion MRI

Gopal Varma1, Timothy Lockie2, Julien Senegas3, Stephen Keevil4, Sven Plein1,5, Tobias Schaeffter1

1Division of Imaging Sciences, King's College London, London, UK; 2Cardiovascular Division, King's College London, London, UK; 3Philips Research Europe, Hamburg, Germany; 4Medical Physics, Guy's & St Thomas' NHS Foundation Trust, London, UK; 5Academic Unit of Cardiovascular Research, University of Leeds, Leeds, UK

First pass myocardial perfusion MRI following the intravenous bolus injection of gadolinium-based contrast agents can be used for the non-invasive detection of coronary artery disease. However dark band or rim artefacts along parts of the subendocardial border are a common problem in first pass perfusion studies, which can be mistaken for perfusion defects, in particular by less experienced observers. The source of these artefacts has been attributed to magnetic susceptibility associated with the high concentration of the contrast agent during the first pass. In this work we show that the use of high-resolution susceptibility gradient mapping (SGM) helps to distinguish between perfusion defects and susceptibility induced artefacts. The high-resolution SGM technique uses the first pass perfusion data and thus requires no additional data acquisition.

14:00         3781.     Variability of Perfusion Dark Rim Artifacts Due to Gibbs Ringing

Pedro Ferreira1, Peter Gatehouse2, Peter Kellman3, Chiara Bucciarelli-Ducci2, David Firmin2

1Imperial College London, London, UK; 2Royal Brompton Hospital, London, UK; 3National Institutes of Health, Bethesda, MD, USA

Gibbs ringing is a well known source of Dark Rim Artifacts (DRA) in myocardial perfusion imaging. The visibility of Gibbs DRAs in perfusion studies is very dependent on the position of the subendocardial wall inside the pixel in the absence of zero-filled pre-FFT interpolation. Position variations from frame to frame in a typical gated perfusion study can explain some of the variability often seen in DRAs. Interpolation by zero-filling prior to enlarged FFT regularizes the DRA appearance.

14:30         3782.     Realistic Simulations on the Dark Rim Artifact for Myocardial Perfusion Protocols

Pedro Ferreira1, Peter Gatehouse2, Peter Kellman3, David Firmin2

1Imperial College London, London, UK; 2Royal Brompton Hospital, London, UK; 3National Institutes of Health, Bethesda, MD, USA

Motion and Gibbs artifacts have been previously shown separately as probable sources of Dark-Rim-Artifacts (DRA) in myocardial perfusion imaging. Their relative importance through the cardiac cycle for a range of typical perfusion protocols has not been fully examined. Therefore, the appearance of Gibbs, motion, and T1 and T2* k-space modulation were studied by numerically simulating typical perfusion protocols with different sequences (GRE,bSSFP,h-EPI).

15:00         3783.     Quantification of Myocardial Perfusion with an Undersampled Radial Acquisition

T. H. Kim1, N. Pack2, G. Adluru3, E. V.R. DiBella1

1Radiology, University of Utah, Salt Lake City, UT, USA; 2Bioengineering, University of Utah, Salt Lake City, UT, USA; 3Radiology, University of Pennsylvania, Philadelphia, PA, USA

Myocardial perfusion magnetic resonance imaging is emerging as a useful modality to assess myocardial ischemia, although there remain challenges related to artifacts, coverage, and quantitation. Recently a rapid undersampled radial k-space perfusion sequence was shown to have promise for qualitative perfusion imaging and offered reduced artifacts and increased coverage compared to most other current methods. In this report, we present perfusion results of in vivo cardiac MRI using radial and Cartesian measurement techniques. The new undersampled radial imaging method which offers some control over the effective saturation recovery time can provide more reasonable Ktrans estimates over a range of doses as compared with a more conventional Cartesian method.

 


 
Cardiovascular Dynamics
Exhibit Hall 2-3                    Monday 14:00-16:00          Computer 44

14:00         3784.     Wall Shear Stress Measurement Error in the Common Carotid Artery: A Dual Modality Study

Alex J. Barker1, Fuxing Zhang1, Philip E. Gates2, Luciano A. Mazzaro1, Jonathan Fulford2, Craig J. Lanning3,4, Robin Shandas3,4

1Mechanical Engineering, University of Colorado, Boulder, CO, USA; 2Peninsula Medical School, University of Exeter, UK; 3Division of Cardiology, The Children's Hospital, Aurora, CO, USA; 4Center for Bioengineering, University of Colorado at Denver Health Sciences, CO, USA

Wall shear stress and its regional patterns have been co-located with atherosclerotic lesions. However, vessels known to manifest at-risk lesions, such as the common carotid artery, test the spatial limits of 1.5 T phase-contrast MRI (PC-MRI). The measurement of WSS is also confounded by partial volume errors and in-flow artifacts. An alternative experimental technique, recently developed in our group, uses ultrasound-based particle image velocimetry (Echo-PIV) to determine velocity fields at excellent spatial and temporal resolutions. Therefore, this study addresses the use of these two modalities for calculating WSS directly in arterial flow fields of less than 10 mm in diameter.

14:30         3785.     In-Plane PC-MRI as a Tool for Verification of Non-Newtonian CFD Models of the Flow in Cerebral Aneurysms

Vitaliy L. Rayz1, Loic Boussel2, Alastair J. Martin1, Gabriel Acevedo-Bolton1, Joe R. Leach, Randall T. Higashida3, Michael T. Lawton3, William L. Young4, David Saloner1

1Radiology, University of California San Francisco, San Francisco, CA, USA; 2Créatis-LRMN (LB, PCD),  UMR CNRS 5515, INSERM U630, Lyon, France; 3Neurological Surgery, University of California San Francisco, San Francisco, CA, USA; 4Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, CA, USA

MR angiography and velocimetry were used to construct patient-specific computational model of the flow in a giant basilar aneurysm. The flow fields predicted by CFD using the Carreau viscosity model with two different set of parameters were compared to Newtonian CFD predictions, as well as to the in-plane PC-MRI data obtained in vivo. The Newtonian flow field shows better agreement with the in vivo flow than does the non-Newtonian results obtained in both cases. While CFD provides high resolution data that cannot be accurately obtained from imaging only, PC-MRI is important for verification of the numerical predictions and modeling assumptions.

15:00         3786.     Computer-Aided Method for Automated Selection of Optimal Imaging Plane for Measurement of Cerebral Volumetric Blood Flow Rate by MRI

Pang-Yu Teng1, Noam Alperin1

1University of Illinois, Chicago, IL, USA

Quantification of volumetric blood flow by PCMRI is becoming more widely used for noninvasive measurement of total cerebral blood flow and intracranial pressure. Current computer guided methods utilize separate scans for each of the four blood vessels leading blood to the brain to obtain a measurement in a plane that is perpendicular to the flow direction. In order to reduce scan time and increase measurement reliability, it is desirable to identify an imaging plane that simultaneously acquires the blood flows in the 4 vessels most perpendicularly. Therefore, we propose an automated method to identify this imaging plane and compare the computer selected planes with those selected by a radiologist. The result shows that computer-aided method (CAM) consistently outperforms the radiologist.

15:30         3787.     High-Resolution Time-Resolved 3D Quantitative Flow MRI of Intracranial Vessels

Marco Piccirelli1, Gérard R. Crelier2, Roger Luechinger1, Sebastian Kozerke1, Peter Boesiger1

1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland; 2Gyrotools GmbH, Zurich, Switzerland

Hemodynamic data improve the understanding of vascular abnormalities. Intracranial arteries diseases are interlinked with abnormal flow patterns. However, the relative small size of these arteries requires acquisition of velocity information with high spatial resolution. We tested 3D quantitative flow MRI protocols for spatial resolution from 0.5-0.15mm3. Velocity profiles were compared for several cerebral arteries for all phases of the cardiac cycle. Our results indicate that time-resolved 3D quantitative flow measurements of the intracranial arteries is feasible with a spatial resolution down to 0.3mm3. Further, very small arteries such as the posterior communicating arteries were clearly visible.

 
Exhibit Hall 2-3                    Tuesday 13:30-15:30          Computer 44

13:30         3788.     Pulse Wave Velocity in Patients with Bicuspid Aortic Valve and Normal Controls: Discriminatory Ability Among Multiple Analysis Techniques

Thananya Boonyasirinant1, Randolph M. Setser1, Prabhakar Raijiah2, Milind Y. Desai, Scott D. Flamm1

1Radiology, Cleveland Clinic, Cleveland, OH, USA; 2Radiology, Cleveland Clinic, Cleveland Clinic, OH, USA

Aortic compliance has become a surrogate marker, however this has been little studied with velocity-encoded MRI in bicuspid aortic valve (BAV). While pulse wave velocity (PWV) is a powerful assessment tool, there are multiple techniques to assess the time delay of the velocity waveform. This study demonstrated increased PWV in BAV compared to controls with all 3 PWV analysis techniques. However, the results emphasize the different discriminatory abilities of the 3 PWV analysis techniques with technique 1 (arrival of the foot measured as the interception of steep early systolic slope and baseline) providing the greatest AUC by ROC analysis.

14:00         3789.     Measuring Effective Orifice Area in Patients After Aortic Valve Replacement Using Phase-Contrast Cine Magnetic Resonance Imaging

Haruhiko Machida1, Eiko Ueno1, Mikihiko Fujimura1, Kazufumi Suzuki1, Satoru Morita1, Ai Masukawa1, Masami Hirata1, Shinya Kojima1, Shoji Sasaki1, Kiyoharu Nakano1, Yoshiaki Komori2

1Tokyo Women's Medical University Medical Center East, Tokyo, Japan; 2Siemens-Asahi Medical Technologies, Tokyo, Japan

Although effective orifice area is usually measured by transthoracic ultrasonography after aortic valve replacement to assess patient-prosthesis mismatch, its accuracy remains unclear. We measured effective orifice area using a continuity equation on phase-contrast cine MR imaging, to our knowledge, an approach not previously reported; then compared those measurements to reference values. We believe that this MR technique is clinically feasible for relatively easy and accurately measuring effective orifice area in patients after aortic valve replacement.

14:30         3790.     Assessment of Papillary Muscle Function Using MRI Tissue Tagging

Randolph M. Setser1, Melanie S. Kotys2, Thananya Boonyasirinant1, Scott D. Flamm1

1Imaging Institute, Cleveland Clinic, Cleveland, OH, USA; 2Philips Healthcare, Cleveland, OH, USA

Papillary muscle (PM) function is intrinsically linked with global left ventricular (LV) function and helps to maintain LV shape. This study evaluated PM strain in healthy volunteers (n=7) and patients (n=2) using MRI with tissue tagging. Strain was -21±4% in the anterior PM and -20±4% in the posterior PM (NS). However, strain was significantly greater in the anterior PM than in the adjacent LV wall (p=0.02). These results are consistent with previous studies. It is feasible to measure strain reliably in patients using tagged MRI. Furthermore, this study provides a basis for evaluating patients in whom PM function might be impaired.

15:00         3791.     Quantification of 3-Directional Motion of Papillary Muscle Using Tissue Velocity Mapping in Patients with Mitral Valve Prolapse

Yuchi Han1, Kraig V. Kissinger1, Beth Goddu1, Warren J. Manning1,2, Reza Nezafat1

1Medicine/Cardiology, BIDMC/Harvard Medical School, Boston, MA, USA; 2Radiology, BIDMC/Harvard Medical School, Boston, MA, USA

In patients with mitral valve prolapse, the tension exerted by the thickened and enlongated mitral leaflets on the papillary muscle during systole may be important in understanding mitral regurgitation progression and the generation of papillary muscle fibrosis. We sought to investigate the feasibility of high spatial and temporal resolution MR phase contrast technique to investigate the 3D motion of papillary muscle and its velocity in MVP patient as well as healthy subjects.

 
Exhibit Hall 2-3                    Wednesday 13:30-15:30          Computer 44

13:30         3792.     Dynamic Evaluation of Lower Extremity Varicosities: Preliminary Experience with Isotropic Time-Resolved Direct Magnetic Resonance Venography (TR-MRV) at 3 Tesla.

Derek G. Lohan1, Roya Saleh1, Steven Hsu1, Christopher Loh1, Stephen T. Kee1, Daniel Ennis1, Gerhard Laub1, J. Paul Finn1

1Radiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA

Laser/radiofrequency thermal ablation has generated renewed enthusiasm regarding imaging options for lower extremity varicose veins. Central to their success is the assumption that pre-operative evaluation, using Doppler sonography, provides a reliable anatomic and functional map of this complex, variable vascular system. Such time-consuming cartography (often in excess of 60 minutes) places considerable demands upon both the technician and patient. Failure of identification of even a single incompetent perforating vein may result in recurrent varicosities. We describe an innovative, rapid though morphologically and functionally informative dynamic MR technique capable of challenging sonography as the reference standard for pre-operative varicose vein imaging.

14:00         3793.     Reproducibility of  MR Arteriography and  Cine Phase-Contrast Flow Measurements in Peripheral Arterial Disease

Bastiaan Versluis1,2, Marcelle van Eupen1, Patty J. Nelemans3, Ellen V. Rouwet4, Joep A.W. Teijink4, Joachim E. Wildberger1, Walter H. Backes1, Tim Leiner1

1Radiology, Maastricht University Medical Center, Maastricht, Netherlands; 2Cardiovasculair Research Institute Maastricht (CARIM), Maastricht, Netherlands; 3Epidemiology, Maastricht University Medical Center; 4Vascular surgery, Atrium Medical Center Heerlen

The aim was to assess the reproducibility of MR arteriography to quantify the number of small arteries and flow of conduit arteries. Ten healthy volunteers and ten patients with proven PAD and collateral formation were prospectively imaged twice within one week.

14:30         3794.     Time-Resolved MR Angiography of the Distal Lower Extremities: Clinical Application, Vessel Diameters, and Contrast Dynamics

Gurpreet Singh Sandhu1,2, Rod P. Rezaee3, Jeffrey L. Duerk1,4, Mark A. Griswold1,4, Vikas Gulani1,2

1Department of Radiology, University Hospitals of Cleveland, Cleveland, OH, USA; 2Case Center for Imaging Research, Case Western Reserve University, Cleveland, OH, USA; 3Department of Otolaryngology-Head and Neck Surgery, University Hospitals of Cleveland, Cleveland, OH, USA; 4Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA

Bolus-chase contrast enhanced MR angiography (ceMRA) of the distal leg does not provide dynamic information about arterial blood flow and suffers from limitations such as missed boluses and venous contamination. Here, application of dynamic contrast-enhanced MR angiography using time resolved imaging with stochastic trajectories (TWIST) for arteriography of the distal leg is described and a quantitative analysis of contrast dynamics of lower legs is performed. A quantitative comparison of apparent arterial lumen diameters in dynamic images obtained with the TWIST method and images acquired with a ceMRA method is also performed.

15:00         3795.     Development of an MR Technique to Investigate the Effects of Respiration and Muscle Contraction on the Venous Blood Flow in the Lower Leg

Iain Thomas Pierce1, Peter D. Gatehouse2,3, David N. Firmin2,3, Xiao Yun Xu3, Andrew D. Scott3

1NHLI, Imperial College London, London, UK; 2Royal Brompton Hospital Trust, UK; 3Imperial College London, UK

A description of an MR technique that makes use of spiral readout gradients and Phase Contrast imaging, developed and optimised to investigate the blood flow in the lower limb venous system for investigation into aetiology of DVT. Here showing the dependency of the blood velocity in the Posterior Tibial Vein and an intra-muscular vein with regular respiration, cardiac ‘drawing’ through IVC and calf muscle contraction.

 
Exhibit Hall 2-3                    Thursday 13:30-15:30          Computer 44

13:30         3796.     Quantitative Evaluation of Magnetohydrodynamic Effects on the Electrocardiogram

Mihaela Jekic1, Roger Dzwonczyk2, Yu Ding3, Subha V. Raman2, Orlando P. Simonetti4

1Biomedical Engineering, The Ohio State University, Columbus, OH, USA; 2The Ohio State University Medical Center, Columbus, OH, USA; 3Davis Heart and Lung Research Institute, Columbus, OH, USA; 4Internal Medicine and Radiology, The Ohio State University, Columbus, OH, USA

Electrocardiogram (ECG) data acquired inside the MRI room may be distorted by magnetohydrodynamic (MHD) effects resulting from blood flow within the magnetic field. We quantified the MHD effects over a range of magnetic field values measured at various positions on the extended MRI table in order to determine a threshold at which MHD effects become significant. We found that at a field strength of <100 mT, the MHD effects are contained within approximately 5% of the baseline non-distorted ECG waveform. This finding is important for monitoring patients during and after stress testing inside the magnet room.

14:00         3797.     Eddy Current Corrections for Phase Contrast MRI Using Gradient Calibration

Kevin Michael  Johnson1, Darren Lum2, Oliver Wieben1

1Medical Physics, University of Wisconsin - Madison, Madison, WI, USA; 2Radiology, University of Wisconsin - Madison, Madison, WI, USA

This study investigates a thin slice gradient calibration scheme to correct for otherwise uncompensated phase errors in quantitative MR velocity mapping caused by eddy currents and gradient imperfections. A short calibration pre-scan was introduced into radial and Cartesian PC sequences to predict the phase errors that occur during scanning so they can be corrected for during the reconstruction process. In phantom evaluations, these corrections significantly reduced linear phase offset errors caused by gradient deviations. In-vivo measurements of Qp/Qs ratios in healthy volunteers showed improved consistency between the measurements and physiologically expected values when the correction scheme was used.

14:30         3798.     Anti-Aliasing Acquisition (AAA) Decreases Study Duration While Maintaining Accuracy in Cardiac MR Flow Exams

Jordin Daniel Green1,2, David John Patton2, Qing-San Xiang3

1Siemens Healthcare, Calgary, Alberta, Canada; 2University of Calgary, Calgary, Alberta, Canada; 3University of British Columbia, Vancouver, British Columbia, Canada

Using a conventional flow quantification sequence, the user is typically required to repeat scans to ensure that velocity sensitivity is high enough to maintain accuracy yet low enough to avoid velocity aliasing. Anti-Aliasing Acquisition (AAA) is a flow imaging technique that avoids aliasing while still maintaining high velocity sensitivity. We demonstrated in patients that one AAA scan could be used to accomplish what typically requires multiple conventional scans, reducing study duration. Comparing the AAA to the conventional technique for accuracy, we computed a Cronbach’s Alpha coefficient of 0.999 for measures of mean, maximum, and minimum flow.

15:00         3799.     Improved SNR in Phase Contrast Velocimetry with 5-Point Balanced Flow Encoding

Kevin Johnson1, Michael Markl2

1Medical Physics, University of Wisconsin - Madison, Madison, WI, USA; 2Medical Physics, University of Freiburg, Freiburg, Germany

This study investigates the use of a novel 5-point velocity encoding scheme for improved noise performance in phase contrast velocimetry with minimal scan time increase. Phantom validations show a 62% increase in velocity to noise ratio as compared to standard 4-point encoding. Additionally is shown in volunteers that low resolution images can be used for the 5th encoding point, allowing the same noise reduction with as little as 0.1% increase in scan time. All this is achieved with minimal increase in the size of the bipolar velocity encoding gradients compared to existing techniques.

 


 
Cardiac Quantitative Wall Motion Techniques
Exhibit Hall 2-3                    Monday 14:00-16:00          Computer 45

14:00         3800.     Cardiac-Specific GLUT1 Overexpression Preserves Contractile Reserve in Diabetic Mouse Hearts: A Multi-Phase DENSE MRI Study Under Dobutamine-Induced Cardiac Stress

Jia Zhong1,2, Fang Bian1,2, Wei Li1,2, Priyanjana Chaudhuri1, Rong Tian3, Xin Yu1,2

1Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA; 2Case Center for Imaging Research, Case Western Reserve University, Cleveland, OH, USA; 3NMR Laboratory for Physiological Chemistry, Brigham and Women’s Hospital, Boston, MA

Diabetes is associated with increased cardiac morbidity and mortality. In our previous study, we found that basal cardiac function in diabetic mice was normalized through improved glucose metabolism via cardiac-specific overexpression of a glucose transporter (GLUT1-TG). In the current study, contractile reserve in GLUT1-TG diabetic mice was examined under dobutamine stimulation using multi-phase DENSE MRI. Our results showed that â-adrenergic response was preserved in GLUT1-TG diabetic mice. Therefore, enhanced glucose oxidation and glycolysis has the beneficial effects of preserved contractility and contractile reserve in diabetic mouse hearts.

14:30         3801.     2D Multi-Phase DENSE MRI with Direct Quantification of Lagrangian Strain in Mouse Hearts

Jia Zhong1,2, Xin Yu1,2

1Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA; 2Case Center for Imaging Research, Case Western Reserve University, Cleveland, OH, USA

Displacement Encoding with Stimulated Echoes (DENSE) allows noninvasive quantification of regional cardiac function by encoding myocardial displacements directly in the phase images of its stimulated echo. However, the low SNR remains a challenge for multi-phase DENSE in mouse hearts. In addition, the need for accurate 2D phase unwrapping hinders the automatic and direct quantification of Lagrangian strains. In the current study, we developed a 2D multi-phase DENSE method with direct Lagrangian strain quantification and validated it by MR tagging. The proposed method showed feasibility in delineating cardiac function over the entire cardiac cycle with high temporal and spatial resolution.

15:00         3802.     Theoretical Validation of Fast Cine DENSE MRI for Quantification of Regional Cardiac Function

Li Feng1, Daniel Kim2

1Biomedical Enginnering, Polytechnic Institute of New York University, Brooklyn, NY, USA; 2Center for Biomedical Imaging and Radiology, NYU Langone Medical Center, New York, NY, USA

Quantitative assessment of regional cardiac function may additionally improve the accuracy of detecting subtle wall motion abnormalities due to heart disease. Recently developed fast cine displacement-encoded with stimulated echoes (DENSE) MRI is a promising modality for the quantification of regional myocardial function. While this pulse sequence is promising for clinical applications, it has not been validated. Therefore, the purpose of this study was to validate the relative accuracy of fast cine DENSE MRI using computer simulation

15:30         3803.     Comparison of 2D and 3D Torsion Measured from Tagged Cardiac MRI

Bharath Ambale1, Steven Lloyd2, Himanshu Gupta2, Louis Dell'Italia2, Thomas Stewart Denney Jr. 1

1Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, USA; 2Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, USA

In tagged MRI, left ventricular torsion vs. time data is typically measured using by tracking an annular mesh in an apical and a basal slice with 2D HARP analysis. 2D techniques, however, do not account for through plane myocardial motion. This study compared the 2D HARP method with a recently developed 3D torsion vs. time method. While 2D and 3D rotation and torsion measurements were similar in subjects with low base-to-apex motion such as patients with myocardial infarction, The 3D method measured larger and probably more accurate rotation and torsion in subjects with normal or elevated base-to-apex motion.

 
Exhibit Hall 2-3                    Tuesday 13:30-15:30          Computer 45

13:30         3804.     Does Surgical Intervention for Myocyte Transfection Impact on Cardiac Function in Mice?

Erica Dall'Armellina1, Craig A. Lygate1, Hannah Barnes1, Ricardo Carnicer1, Stefan Neubauer1, Michael Markl2, Bernd A. Jung2, Jurgen E. Schneider1

1Department of Cardiovascular Medicine, University of Oxford, Oxford, Oxon, UK; 2University Hospital Freiburg, Freiburg, Germany

Direct intra-myocardial injections are often used for viral gene transfer experiments in the mouse, however, myocyte transfection by this route is inhomogeneous, localised mainly around the sites of injection. Tissue phase mapping (TPM) could be a useful tool to detect small changes to regional function in vivo after direct injection of genetic material. However, it is first necessary to determine whether the surgical intervention required injecting the heart, has itself an effect on regional cardiac function and on baseline TPM parameters. We have therefore used TPM longitudinally in the same mouse to track changes in regional function at baseline, and 24 hours and 8 days after direct intra-myocardial injection of saline. We found that only the anterior wall exhibited a relative impairment in regional function after surgery, which may be related to the removal of the pericardium rather than the injection. Importantly, no change in global cardiac function (i.e. ejection fraction (EF) and stroke volume (SV)) could be detected

14:00         3805.     Tissue Phase Mapping Reveals Profound Alterations of Segmental Left Ventricular Performance in Patients with Cardiomyopathy and Left Bundle Branch Block

Daniela Foell1, Bernd Jung2, Elfriede Schilli1, Felix Staehle2, Christoph Bode1, Juergen Hennig2, Michael Markl2

1Cardiology and Angiology, University Hospital Freiburg, Freiburg, Germany; 2Dept. of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany

MR Tissue phase mapping (TPM) allows the visualization of the distribution of myocardial velocities and their timing with complete LV coverage. Left bundle branch block (LBBB) and the associated asynchrony of LV function is associated with reduced prognosis in cardiomyopathy. Using TPM we could demonstrate a variety of differences in segmental myocardial performance in patients with dilated cardiomyopathy and LBBB compared to patients without LBBB.

14:30         3806.     Analysis of Segmental Diastolic Asynchrony in Patients with LV Hypertrophy Using Tissue Phase Mapping

Daniela Foell1, Michael Markl2, Elfriede Schilli1, Felix Staehle2, Christoph Bode1, Juergen Hennig2, Bernd Jung2

1Cardiology and Angiology, University Hospital Freiburg, Freiburg, Germany; 2Dept. of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany

The aim of this study was to evaluate complete segmental left ventricular performance in patients with left ventricular hypertrophy due to hypertension compared to healthy volunteers. Using MRI Tissue Phase Mapping (TPM) we could demonstrate extensive alterations in magnitude, timing and distribution of diastolic myocardial velocities within the left ventricle in the patients.

15:00         3807.     Changes in Longitudinal and Radial Strain After Coronary Embolization Detected on Velocity Encoded Phase Contrast Magnetic Resonance Imaging

Marcus Carlsson1,2, Demetrius Dicks1, Einar Heiberg2, Alastair Martin1, David Saloner1, Hakan Arheden2, Maythem Saeed1

1UCSF, Dep of Radiology and Biomedical Imaging, San Francisco, CA, USA; 2Lund University Hospital, Dep of Clinical Physiology, Lund, Sweden

This MRI study determined the ability of phase velocity encoded (PC-MR) strain to detect the functional effects on left ventricular radial and longitudinal strain after microembolization in the LAD coronary artery in an animal model. PC-MR imaging was sensitive to dectect the changes in longitudinal and radial strain after selective LAD coronary embolization. Longitudinal strain of the patchy microinfarction declined from baseline to 1-hour after embolization, a decline that persisted at 1 week. Radial strain declined acutely 1-hour after LAD embolization and worsened at 1 week post-embolization.

 
Exhibit Hall 2-3                    Wednesday 13:30-15:30          Computer 45

13:30         3808.     Retrospective Enhancement of Radially Undersampled Cardiac Cine MR Images Using Prior Image Constrained Compressed Sensing (PICCS)

Christopher J. François1, Jie Tang2, Guang Hong Chen1,2

1Radiology, University of Wisconsin, Madison, WI, USA; 2Medical Physics, University of Wisconsin, Madison, WI, USA

Real-time cardiac cine magnetic resonance (MR) imaging uses k-space undersampling to accelerate image acquisition. This abstract presents a method of enhancing radially undersampled cardiac cine MR images using prior image constrained compressed sensing (PICCS). Undersampled datasets reconstructed using filtered back projection (FBP), compressed sensing (CS), and PICCS were compared. Images reconstructed with PICCS were of much higher quality than those using FBP and CS. PICCS represents a feasible method of generating high-quality cardiac cine MR images using real-time techniques which are important in patients who cannot hold their breath or who have arrhythmias.

14:00         3809.     Assessment of Left Ventricular Function with Single Breath-Hold Highly Accelerated Cine MRI Combined with Guide-Point Modeling

Christina Heilmaier1, Kai Nassenstein1, Sonia Nielles-Vallespin2, Sven Zuehlsdorff2, Peter Hunold1, Joerg Barkhausen1

1University Hospital Essen, Essen, NRW, Germany; 2Siemens AG Healthcare Section

 

14:30         3810.     Local Noise Measurement in Real-Time Cardiac Cine MRI - A Random Matrix Approach

Yu Ding1, Yiu-cho Chung2, Orlando P. Simonetti1

1The Ohio State University, Columbus, OH, USA; 2Siemens Medical Solutions USA, Inc., Columbus, OH, USA

We propose a novel technique based the random matrix theory to generate a stack of noise-only images in a dynamic MR image series. Accurate local noise can be assessed in these noise-only images. This new method is validated using real-time cardiac MR cine images with TSENSE acceleration factor 3, 4 and 5.

15:00         3811.     Denoising of Highly Accelerated  Real-Time Cardiac MR Images Using Extended Non-Local Means

Jean-Noël Hyacinthe1,2, Benoit Naegel3, Maurizio Tognolini4, Jean-Paul Vallée1,2

1Faculty of medecine, University of Geneva, Geneva, Switzerland; 2Work supported in part by the Center for Biomedical Imaging (CIBM), Geneva and Lausanne  , Switzerland; 3LORIA-UMR 7503, Vandoeuvres les Nancy, France; 4Swiss University of Applied Sciences, Geneva, Switzerland

Real-time cardiac MRI is of clinical importance in some patients (e.g. with arrythmias or in pediatrics). However, standard real-time MRI suffers from compromised spatiotemporal resolution. A new method for real-time denoising is presented to overcome signal-to-noise ratio (SNR) limitations of highly accelerated TSENSE acquisitions. This method is based on a multi-resolution rigid registration and an extended non-local means filter that uses redundancy between successive frames. The performances of this method, studied in 5 volunteers and 5 patients, and its computational efficiency allow in-line processing of highly accelerated real-time cardiac images, and should be compatible with clinical applications including stress studies.

 
Exhibit Hall 2-3                    Thursday 13:30-15:30          Computer 45

13:30         3812.     High-Resolution Transmural 3D Myocardial Strains Using 3D Tissue Tagging with Optical Flow Tracking

Chun Xu1, Kevin Koomalsingh1, Aaron S. Blom1, Larry Dougherty2, Gamaliel Isaac2, Joseph H. Gorman1, Robert C. Gorman1, James J. Pilla1,2

1Surgery Department, Hospital of University of Pennsylvania, Philadelphia, PA, USA; 2Radiology, University of Pennsylvania, Philadelphia, PA, USA

This study presents a novel method to accurately quantify transmural deformation in the left ventricle. A special pulse sequence was developed that applied the optimized SPAMM tag pulse in three distinct planes in one acquisition. Displacements of pixels were tracked using an optimized 3D optical flow method, and used to compute systolic principal strain magnitude and orientation. Minimal user interface were required and results are in agreement with previous reported data, but with sufficient resolution for transmural LV strain evaluation.

14:00         3813.     Mapping Myocardial Mechanical Activation by MRI Tagging and HARP

Martina Marinelli1,2, Piergiorgio Masci2, Daniele De Marchi2, Massimo Lomabrdi2, Luigi Landini2,3, Vincenzo Positano2

1Scuola Superiore Sant'Anna, Pisa, Italy; 2MRI Lab, “G. Monasterio” Foundation and Institute of Clinical Physiology, CNR, Pisa, Italy; 3Department of Information Engineering, University of Pisa, Pisa, Italy

Non invasive evaluation of heart mechanical dyssynchrony is important in diagnosis and follow-up of dilated cardiomyopathy. In this study we present a MR tagging-HARP method for myocardial mechanical activation monitoring. Feasibility of the proposed approach was tested on small subject population.

14:30         3814.     Comparison of 2D and 3D Calculation of Left Ventricular Torsion as Circumferential-Longitudinal Shear Angle Using MRI Tagging

Iris K. Rüssel1, Sandra R. Tecelão2, Joost P. Kuijer1, J Tim Marcus1

1VU University Medical Center, Amsterdam, Netherlands; 2University of Lisbon, Lisbon, Portugal

Left ventricular torsion can be calculated from 2D or 3D datasets, where the 2D method is faster, but the 3D method closer to the true torsion. Both methods are compared to indicate whether it is legitimate to calculate torsion from 2D datasets only. Both methods were found to be strongly related and differences were linear and predictable. Therefore it is legitimate to use the faster 2D method for torsion calculation.

15:00         3815.     Very High Temporal Resolution (<10 Ms) Cine-EPI for Myocardial Tagging Is Feasible and Has More Persistent Tag Lines Than a Conventional Gradient Echo Sequence

Jordin Daniel Green1,2, Renate Jerecic3, Andreas Kumar2, Oliver Strohm2, Sonia Nielles-Vallespin4, Sven Zuehlsdorff3

1Siemens Healthcare, Calgary, Alberta, Canada; 2University of Calgary, Calgary, Alberta, Canada; 3Siemens Medical Solutions USA, Inc., Chicago, IL, USA; 4Siemens Healthcare, Erlangen, Germany

Cine imaging with myocardial tagging is an important clinical tool for the evaluation of ventricular performance. Tagging sequences must have high temporal resolution to detect subtle wall motion defects and also have tags which are preserved for as long as possible during the cardiac cycle. We developed a cine-EPI sequence with a high temporal resolution (<10 ms). Using simulations and in vivo experiments, we demonstrated that, when compared to a tagged cine-GRE sequence, image quality is maintained for the cine-EPI sequence, but there is a statistically significant improvement in tag duration (GRE: 456±48 ms; EPI: 530±64).

 


 
Coronary Arteries, Vessel Wall & Vascular Image Processing
Exhibit Hall 2-3                    Monday 14:00-16:00          Computer 46

14:00         3816.     Respiratory Self-Gating with 3D-Translation Compensation for Whole-Heart Coronary MRA

Peng Lai1, Xiaoming Bi2, Renate Jerecic2, Debiao Li1

1Departments of Biomedical Engineering and Radiology, Northwestern University, Chicago, IL, USA; 2Siemens Medical Solutions, Chicago, IL, USA

Conventional respiratory gating methods, e.g. NAV and respiratory self-gating (RSG), detect SI translation of the heart only, resulting in residual motion artifacts. This work developed a new 3D RSG method capable of detecting 3D heart translation in real-time was for whole-heart coronary MRA. Coronary imaging was performed on 9 volunteers with both NAV and 3D RSG signals acquired. Images were reconstructed using different motion correction methods and compared based on vessel delineation. Our results showed that 3D RSG improved coronary artery depiction compared to conventional methods. 3D RSG is a promising technique for improving the robustness of whole-heart coronary MRA.

14:30         3817.     Free-Breathing Versus Breath-Hold 32-Channel Coronary Vessel Wall Imaging at 3T

Andrea J. Wiethoff1,2, John J. Totman1,3, Rene M. Botnar1,4, Matthias Stuber5

1Division of Imaging Sciences, King's College London, London, UK; 2Philips Healthcare, Reigate, UK; 3NIHR Biomedical Research Centre at Guy’s & St Thomas’ Hospital and King’s College London; 4NIHR Biomedical Research Centre at Guy’s & St Thomas’ Hospital and King’s College London ; 5Department of Radiology, Johns Hopkins University, Baltimore, MD, USA

Breath-hold black-blood coronary vessel wall imaging with a high spatial resolution is enabled by the combination of 3T, spiral imaging and 32-channel coil architecture. This preliminary study shows promising results and suggests that a breath-hold approach provides a valuable alternative for those subjects capable of holding their breath for a relatively long period while the navigated version is optimal for those who cannot maintain a breath-hold.

15:00         3818.     Coronary Artery Distensibility Assessed by 3.0 T Cardiac MRI

Sebastian Kelle1, Allison G. Hays1, Glenn A. Hirsch1, Gary Gerstenblith1, Robert G. Weiss1, Matthias Stuber1

1Johns Hopkins University, Baltimore, MD, USA

We used 3T MRI to non-invasively assess human coronary artery vessel wall distensibility and observed significant differences between healthy subjects and CAD patients. With the available data to date, we do not observe a significant correlation between coronary artery distensibility and aortic distensibility either in healthy adults or CAD atients. This new methodology may support the non-invasive characterization of ascular anatomy and function in healthy and diseased states, as well as the response to interventions in patients with, or at increased risk for, CAD.

15:30         3819.     Coronary Artery Imaging at 3T Using a Novel ECG Gated SSFP-Dixon Sequence and a Motion Insensitive View Ordering Scheme

Manojkumar Saranathan1, Ersin Bayram2, Vijay Nimbargi3, Ramesh Venkatesan3, James Glockner4

1Applied Science Laboratory, GE Healthcare, Rochester, MN, USA; 2MR Engineering, GE Healthcare, Waukesha, WI, USA; 3GE Healthcare, Bangalore, India; 4Dept. of Radiology, Mayo Clinic, Rochester, MN, USA

MR Coronary Artery Imaging (CAI) remains challenging due to constraints imposed by physiological motion as well as stringent fat and background suppression requirements. 3D ECG gated steady state free precession (SSFP) imaging has shown great promise due to its high SNR, excellent blood-myocardium contrast and short scan times. Robust fat suppression is challenging at high field strengths due to B0 and B1 inhomogeneities. Further, fat saturation pulses perturb the steady state, causing severe artifacts. We report a novel ECG gated dual-echo 3D SSFP sequence with a two-point Dixon fat-water reconstruction algorithm and demonstrate its potential for imaging the coronary arteries at 3T.

 
Exhibit Hall 2-3                    Tuesday 13:30-15:30          Computer 46

13:30         3820.     Noninvasive in Vivo High-Resolution MRI of Vessels Affected by Transplant Rejection in Mice: As Good as Histopathological Analysis?

Andreas Hess1, Julia Gehardt2, Lubos Budinsky, Udo Reulbach3, Stephan M. Ensminger2

1Pharmacological Imaging, I. f. Pharmacology, Erlangen, NA, Germany; 2Cardiac Surgery, University of Erlangen Nuremberg; 3Psychiatry and Psychotherapy, University of Erlangen Nuremberg

Major limitation of the investigation of transplant vasculopathy in mice is, that it’s difficult to monitor the progression and potential response to therapy in vivo. The aim of this study was to proof that the detection of the residual lumina by MR angiography (TOF and/or PCA) imaging in the anesthtized mouse is comparable with those achieved by histopathological analysis.

14:00         3821.     Coronary Artery Motion Analysis in Patients with Atrial Fibrillation Using Real-Time True FISP Cine Imaging to Reduce Artifacts in CT and MR Coronary Angiographies

Yoshiro Hori1, Naoaki Yamada1, Masahiro Higashi1, Tadashi Watabe1, Tetsuro Nakazawa1, Atsushi Kono1, Suzu Kanzaki1, Tetsuya Fukuda1, Hiroaki Naito1

1Department of Radiology and Nuclear Medicine, National Cardiovascular Center, Suita, Osaka, Japan

We evaluated coronary artery motion in patients with atrial fibrillation (Af) using real-time True FISP cine MR imaging.

14:30         3822.     High-Resolution Ex-Vivo MR Angiography of the Murine Heart Using Langendorff Gd-DTPA Perfusion Technique

Steven F. Tanner1, David Benoist1, Justin F X  Ainscough1, Edward White1, Michael E. Ries1, Aleksandra Radjenovic1

1University of Leeds, Leeds, UK

This paper describes a technique for the acquisition of 3D MR angiograms from the ex-vivo murine heart with ~60µm isotropic spatial resolution. The technique enables visualisation of the epicardial vessel architecture, and identification of branching vessels with the diameter of ~120µm. Alterations in epicardial vessel architecture caused by pathology or genetic variation/modification occurring in vessels of this size (or greater) could therefore become apparent using this approach.

 
Exhibit Hall 2-3                    Wednesday 13:30-15:30          Computer 46

13:30         3823.     Accuracy and Reproducibility of Breath-Hold Velocity-Encoded MRI with Spiral K-Space Sampling in the Right Coronary Artery Using 3T MRI

Anne Brandts1, Stijntje D. Roes1, Joost Doornbos1, Albert de Roos1, Matthias Stuber2, Jos J.M. Westenberg1

1Radiology, Leiden University Medical Center, Leiden, South-holland, Netherlands; 2Radiology, Johns Hopkins University Medical School, Baltimore, USA

3T velocity-encoded in vivo human MRI with spiral k-space sampling is an accurate and reproducible method for the assessment of flow velocity patterns in the right coronary artery in healthy volunteers.

14:00         3824.     Design and Validation of an Accurate, Reproducible and MR Compatible Respiratory Motion Phantom for Use in Coronary Artery and General MR Imaging

Andrew David Scott1,2, Jenny Keegan2, David Firmin1,2

1Cardiovascular Magnetic Resonance Unit, National Heart and Lung Institute, Imperial College London, London, UK; 2Cardiovascular Magnetic Resonance Unit, The Royal Brompton Hospital, London, UK

An MR compatible mechanical phantom that can follow real or simulated respiratory traces, and which can be used with a number of test objects including realistic coronary vessel wall phantoms, was designed. Motion of the phantom has been shown to be consistent and accurate with an RMS error of 0.22mm (<2% amplitude) using sinusoidal and real respiratory motion profiles. The phantom was used to validate motion information derived from a sub-pixel normalised cross correlation of 3D low resolution fat images which is used for correcting 3D high resolution water only images of a moving coronary artery lumen phantom.

14:30         3825.     Automatic Segmentation of 3D Phase Contrast MRI Using Velocity Guided Gradient Vector Flow

Robert L. Janiczek1, Frederick H. Epstein1,2, Scott T. Acton1,3

1Biomedical Engineering, University of Virginia, Charlottesville, VA, USA; 2Radiology, University of Virginia, Charlottesville, VA, USA; 3Electrical Engineering, University of Virginia, Charlottesville, VA, USA

Hemodynamic measurements using phase contrast MRI in mouse models of atherosclerosis provide insight into the molecular mechanisms of the disease. Automatic segmentation using active models could eliminate the need for manual segmentation prior to calculation of hemodynamic parameters such as wall shear stress. Traditionally, active model external forces have relied exclusively on the image magnitude. We propose a new active model external force that incorporates velocity data into the gradient vector flow (GVF) framework. Velocity guided GVF acts to push an active model along the direction of flow and is shown to improve segmentation results when compared to GVF.

15:00         3826.     Validation of Finite-Element Stress Analysis of Abdominal Aortic Aneurysm Using Dynamic MRI

Maarten Merkx1, Marcel van 't Veer2, Marcel Breeuwer3, Lambert Speelman4, Jaap Buth2, Frans van de Vosse1

1University of Technology, Eindhoven, Netherlands; 2Catharina Hospital, Eindhoven, Netherlands; 3Philips Healthcare, Best, Netherlands; 4University Medical Center, Maastricht, Netherlands

An abdominal aortic aneurysm (AAA) is a life-threatening dilatation of the aorta. In clinical practice, the maximum transversal AAA diameter is used to assess its rupture risk and to decide whether or not surgical repair is required. There is however a strong indication that knowledge about the AAA wall stress can provide more accurate rupture-risk prediction than the maximum diameter. In recent years, we have developed a finite-element analysis methodology to derive the patient-specific AAA wall strain and stress from dynamic MRI acquisitions. In this paper, we describe how we have validated our finite-element calculations.

 
Exhibit Hall 2-3                    Thursday 13:30-15:30          Computer 46

13:30         3827.     Characterizing the Brain Arterial Hemodynamics with Subject-Specific MRA-Based Computational Fluid Dynamics Models

Fernando Mut1, Susan Wright2, Giorgio Ascoli2, Juan R. Cebral1

1Computational and Data Sciences, George Mason University, Fairfax, VA, USA; 2Krasnow Institute for Advances Studies, George Mason University, Fairfax, VA, USA

Characterization of the brain arterial hemodynamics is important to compare healthy and pathologic blood flow conditions in order to better understand the mechanisms responsible for the initiation and progression of cerebrovascular diseases such as ischemic strokes and aneurysms. This paper presents a methodology for constructing subject-specific image-based computational models of the brain arterial system from magnetic resonance data, and its application to the characterization of the brain arterial hemodynamics.

14:00         3828.     Computational Fluid Dynamics (CFD)-Based Flow Analysis in Aneurysms: A Comparison Study with 4D Phase-Contrast MR in an in Vivo Canine Aneurysm

Jingfeng Jiang1,2, Kevin Johnson1, Oliver Wieben1,2, Oddrun Myklebust3, Kent-Andre Mardal3, Charles Strother2

1Medical Physics, University of Wisconsin, Madison, WI, USA; 2Radiology, University of Wisconsin, Madison, WI, USA; 3Simula Research Lab, Oslo, Norway

This work presents a comprehensive analysis and comparison of the hemodynamics of an experimental canine aneurysm model based on traditional CFD simulations and novel 4D phase-contrast MR measurements. The MR flow measurements were then compared with "image-based" and “animal specific” CFD simulations using 3D-DSA to obtain aneurysm geometries and ultrasound Doppler/MR measurements for velocity waveforms. Our CFD results as well as 2D Ultrasound Doppler images confirm that 4D PC-MR provides “physically-sound” velocity measurements and therefore may be potentially used for detailed analysis of the disturbed flow that is usually present in intracranial aneurysms.

14:30         3829.     A 3D MRA Segmentation Method Based on Tubular NURBS Model

Avan Suinesiaputra1, Patrick J H de Koning1, Elena Zudilova-Seinstra2, Johan H C Reiber1, Rob J. van der Geest1

1Div. of Image Processing, Dept. of Radiology, Leiden University Medical Center, Leiden, Netherlands; 2Section of Computational Science, University of Amsterdam, Amsterdam, Netherlands

A 3D segmentation method for MRA images is presented. The algorithm uses Non-Uniform Rational B-Splines model of tubular structure. The model’s surface is fitted based on image forces (searching the closest edge) and model forces (keeping the tubular model). Ten patients with indication of carotid arterial diseases were selected. The method was compared on axially sliced 2D expert-drawn contours (831 slices). The average overlapped contour area was 65.18% (SD 10.66%). The correlation coefficient for the cross-sectional area was 0.83 (p < 1e-16). The mean cross-sectional area difference was 2.3±10.1 mm2.

15:00         3830.     Improved Cardiovascular Planning Strategies in Patients with Congenital Heart Disease

Israel Valverde1, Tarinee Tangcharoen2, Hubrecht de Bliek3, Graeme Penney4, Marcel Breeuwer3, Tobias Schaeffter4, Philipp Beerbaum4, Reza Razavi4, Gerald F Greil4

1Division of Imaging Sciences , King's College London, London, UK, UK; 2Division of Cardiology, Department of Internal Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 3Healthcare Informatics / Patient Monitoring, Philips Healthcare; 4Division of Imaging Sciences, King's College London

Planning of cardiovascular magnetic resonance imaging (MRI) exams in patients with congenital heart disease (CHD) is complex and time consuming due to small cardiac and vascular structures in atypical locations. Therefore a new planning tool is presented for accurate and time efficient planning in this group of patients.

 


 
Vessel Wall Imaging
Exhibit Hall 2-3                    Monday 14:00-16:00          Computer 47

14:00         3831.     Multimodality Imaging for Investigation of Plaque Morphology and Blood Flow: Preliminary Results

Florence Trinity Baluyot1, Vijay Shamdasani2, Hunter Underhill1, Baocheng Chu3, William S. Kerwin3, Chun Yuan3

1Bioengineering, University of Washington, Seattle, WA, USA; 2Ultrasound Investigation, Philips Healthcare, Bothell, WA, USA; 3Radiology, University of Washington, Seattle, WA, USA

MRI and ultrasound gives complimentary information that can be used to study flow effects on atherosclerotic lesions in order to improve detection and understanding. Plaque inner and outer walls and flow artifacts were identified in MRI using multi-contrast weighting and compared against flow patterns derived using Vector Doppler imaging. An initial data set of thirty-five MRI slices for five subjects yielded a P-Value of 0.001 when using Fisher’s Exact Test to compare presence of MRI flow artifact against flow reversal in Ultrasound. These findings suggest combining information from MRI and ultrasound can assist reviewers discriminate between flow artifact and plaque.

14:30         3832.     MR Plaque Image: Prediction of the Complication Risk at Carotid Artery Stenting.

Masahiko Sakamoto1, Toshiaki Taoka1, Hiroyuki Nakagawa1, Ktsutoshi Takayama2, Takeshi Wada2, Kaoru Myouchin1, Toshiteru Miyasaka1, Toshiaki Akashi1, Kimihiko Kichikawa1

1Radiology, Nara Medical University, Kashihara, Nara, Japan; 2Ishinkai Yao General Hospital

The purpose is to evaluate the carotid plaque component evaluated by MR plaque image as the finding to predict the complication risk at carotid artery stenting (CAS). Thirty-one carotid plaques of 30 patients were classified to stable and vulnerable groups and compared with the occurrence of slow flow phenomenon as indicator of embolic complication risk and there was significant difference (P<0.05) on chi-square test. The carotid plaque classified the composition as vulnerable by MR plaque image has the significant higher risk of slow flow phenomenon at CAS. The complication risk at CAS can be predicted by MR plaque image.

15:00         3833.     Hemorrhage in Carotid Plaque Is Not a Predictive Marker of New Cardiovascular Events in Asymptomatic IndividualsFA High-Resolution MRI Study

Jianming Cai1, Qingjun Wang1, Lin Ma1, Youquan Cai1, Qian Zhao1

1Radiology, Chinese PLA General Hospital, Beijing, China

By using high-resolution MRI, we investigated prospectively whether hemorrhage in carotid plaque predicts future new cardiovascular events in asymptomatic individuals. Every subject in the present cohort study was given consecutive pre and post contrast-enhanced MRI examinations every 6-9 months and followed up for new cardiovascular events. Our results indicate that no correlation could be established between intraplaque hemorrhage (IPH) and new cardiovascular events. It suggests that carotid IPH can not help to identify patients at risk for future cardiovascular events.

15:30         3834.     Distribution of Intraplaque Calcification in the Femoral Artery: A Multi-Contrast MRI Study

Feiyu Li1, Chun Yuan1, Marina Ferguson1, Dongxiang Xu1, Xihai Zhao1, Mary McGrae McDermott2

1University of Washington, Vascular Imaging Lab, Seattle, WA, USA; 2Northwestern University's Feinberg School of Medicine, Chicago, IL, USA

Analyzing the distribution of intraplaque components is helpful to predict prognosis of atherosclerosis plaques. Various imaging techniques, such as MRI and IVUS, have been extensively developed in this field. But only limited studies have been conducted on peripheral artery lesions. The aim of this study is to investigate the distribution of intraplaque calcification (Ca) in femoral artery using multi-contrast MRI. The results show the difference of calcification distribution in different arterial locations and NWI groups. It seems the distribution of calcification in femoral artery atherosclerosis is strongly associated with the arterial segment and plaque burden.

 
Exhibit Hall 2-3                    Tuesday 13:30-15:30          Computer 47

13:30         3835.     Carotid Contrast Enhanced MRA as a Measurement of Atherosclerosis Severity: Direct Comparison with High-Resolution Vessel Wall Imaging

Li Dong1, Hunter Underhill1, Vasily L. Yarnykh1, Wei Yu2, Hideki Ota1, Xihai Zhao1, Thomas S. Hatsukami3, Zhaoqi Zhang2, Chun Yuan1

1Department of Radiology, University of Washington, Seattle, WA, USA; 2Department of Radiology, Beijing Anzhen Hospital, Beijing, China; 3Department of Surgery, University of Washington, Seattle, WA, USA

We sought to assess correlations between MRA, plaque burden and high-risk plaque features in a clinical atherosclerosis population. Subjects (n=66) with >50% carotid stenosis measured by ultrasound in at least one carotid artery, underwent bilateral contrast-enhanced carotid MRA at 3.0T to determine the degree of stenosis and bilateral carotid MRI to identify plaque burden, composition and fibrous cap status. There was a moderate positive correlation between degree of stenosis and plaque burden, but a weak correlation with plaque composition and cap status. Furthermore, high-risk plaque features were commonly observed in arteries with no or minimal stenosis. These findings suggest a critical role for vessel wall imaging to assess the risk of carotid atherosclerosis for future ischemic events.

14:00         3836.     High-Resolution Black-Blood Contrast-Enhanced T1-Weigthed Images for the Diagnosis of Intracerebral Arteritis: Preliminary Results

Tobias Saam1, Clemens C. Cyran1, Katja Bochmann1, Olaf Dietrich2, Maximilian F. Reiser3, Konstantin Nikolaou4

1Institute of Clinical Radiology, LMU University Munich, Munich, Bavaria, Germany; 2Josef Lissner Laboratory for Biomedical Imaging, Dept. of Clinical Radiology, Josef Lissner Laboratory for Biomedical Imaging, Munich, Bavaria, Germany; 3Institute of Clinical Radiology, LMU University Munich,, Munich, Bavaria, Germany; 4Institute of Clinical Radiology,, LMU University Munich, Munich, Bavaria, Germany

Primary arteritis of the central nervous system (CNS) is a heterogeneous group of CNS disorders which is characterized by nonatheromatous inflammation and necrosis of vessel walls. The clinical presentation is highly variable and the most common symptom is a stroke. Diagnosis is difficult and angiographic findings are often unspecific. Therefore brain biopsy is often needed to confirm the diagnosis. First experience in 10 subjects indicates that high-resolution contrast-enhanced, black-blood T1-weighted images with fat suppression of the cranial arteries might be useful to diagnose CNS arteritis. This information might help to avoid invasive procedures, such as conventional angiography or brain biopsies.

14:30         3837.     In Vivo Differentiation of Two Vessel Wall Layers in Lower Extremity Peripheral Vein Bypass Grafts: Application of High Resolution Inner-Volume Black Blood 3D FSE

Dimitris Mitsouras1,2, Christopher D. Owens3, Michael S. Conte3, Hale Ersoy1,2, Mark A. Creager2,4, Frank J. Rybicki1,2, Robert V. Mulkern2,5

1Radiology, Brigham and Women's Hospital, Boston, MA, USA; 2Harvard University, Cambridge, MA, USA; 3Surgery, Brigham and Women's Hospital, Boston, MA, USA; 4Medicine, Brigham and Women's Hospital, Boston, MA, USA; 5Radiology, Children's Hospital, Boston, MA, USA

Despite its clinical importance, intermediate-term vein bypass graft failure (30-50% of grafts) remains largely uncharacterized due to the resolution required to image the graft wall. Using a high-sampling efficiency inner-volume 3DFSE sequence that achieves T1- and T2-weighted black-blood imaging with 0.3x0.3x2mm uninterpolated resolution at 1.5T in under 10min, we observed a significant difference in vessel wall area between contrasts in lower extremity vein bypass grafts (LEVBG) in vivo, and show that the difference stems from the intrinsic MR signal decay characteristics of the neo-intima/media and adventitia measured in LEVBG specimens ex vivo and correlated to histology.

15:00         3838.     Three-Dimensional T2-Weighted TSE MRI of the Human Femoral Arterial Vessel Wall at 3.0Tesla

Zhuoli Zhang1,2, Zhaoyang Fan1, Timothy Carroll1, Yiu-Cho Chung3, Renate Jerecic3, Peter Weale3, Debiao Li1

1Northwestern University, Chicago, IL, USA; 2VirtualScopics Inc., Rochester, NY, USA; 3Siemens Medical Solutions, Chicago, IL, USA

To evaluate the potential of 3D TSE T2-weighted (SPACE) technique for assessing vessel wall of the superficial femoral artery at 3.0T. 15 healthy volunteers underwent 3D and 2D TSE T2-weighted (T2w) imaging of femoral artery. Muscle-lumen CNR and CNR efficiency was significantly higher with 3D SPACE when compared with the reference standard 2D T2w TSE. The measurements of wall volume (WV) and lumen volume (LV) by SPACE and 2D T2w TSE were highly correlated. 3D SPACE vessel wall imaging of the SFA with the SPACE technique is feasible at 3T clinical setting.

 
Exhibit Hall 2-3                    Wednesday 13:30-15:30          Computer 47

13:30         3839.     In Vivo Contrast-Enhanced (Gd-DTPA) and Ex Vivo Magnetization Transfer and Diffusion Weighted MRI Detect Changes in Thrombus Composition During Propagation from Sites of Disrupted Atherosclerotic Plaques.

Alkystis Phinikaridou1, Kevin J. Hallock2, Ye Qiao1, James A. Hamilton1

1Physiology and Biophysics, Boston University Medical School, Boston, MA, USA; 2Anatomy and Neurobiology, Boston University Medical School, Boston, MA, USA

We combined gadolinium-enhanced in vivo and ex vivo magnetization transfer (MT) and diffusion weighted (DW) MRI to study thrombus formation associated with vulnerable plaques in rabbits. We found that: (i) thrombi propagate parallel and anti-parallel to blood flow from the site of plaque disruption, (ii) in vivo use of Gd-DTPA distinguished the thrombus from the underlying plaque, (iii) ex vivo MT and DW imaging detected changes in thrombus composition during propagation. As thrombi propagate they become enriched in fibrin and circulating blood cells resulting in increased % MT ratio and decreased apparent diffusion coefficient.

14:00         3840.     Phantom Investigation on the Accuracy of Different Pulse Sequences for the Determination of Arterial Distensibility

Valentina Taviani1,2, Andrew James Patterson1, Pauline Wong1, Michael P. Sutcliffe2, Martin John Graves1, Jonathan Harvey Gillard1

1Department of Radiology, University of Cambridge, Cambridge, UK; 2Department of Engineering, University of Cambridge, Cambridge, UK

The distensibility coefficient, often used as an index of arterial elasticity, requires the maximum relative change in the luminal cross-sectional area to be determined. In this work a human-tissue-mimicking phantom was imaged using three different pulse sequences (cine phase-contrast, cine bright-blood and a custom-developed cine black-blood using spatial saturation bands). The results were compared with high resolution digital photography (HRDP) assumed to be the gold-standard. Cine black-blood best agreed with HRDP (rms deviation = 0.011mm) with cine phase data the worst (rms deviation = 0.113mm) resulting in a 26% underestimation of the distensibility coefficient compared to black-blood.

14:30         3841.     Correlation Between Plaque Eccentricity and Vessel Remodeling in the Human Femoral Artery: A Morphology Investigation by High Resolution MRI

Feiyu Li1, Mary McGrae McDermott2, Marina Ferguson1, Dongxiang Xu1, Xihai Zhao1, Chun Yuan1

1University of Washington, Vascular Imaging Lab, Seattle, WA, USA; 2Northwestern University's Feinberg School of Medicine, Chicago, IL, USA

The results from coronary artery studies showed arterial remodeling and plaque eccentricity were two important markers of atherosclerotic plaque burden and subsequent cardiovascular events. The occurrence of coronary expansive remodeling was found associated with eccentric lesions. But few studies focused on peripheral artery disease. The aim of this study is to investigate atherosclerotic vessel wall morphology in femoral artery, in particular lesion eccentricity and remodeling and their relationships using high resolution MRI. The results demonstrated eccentric disease occurred more frequently in atherosclerotic femoral artery as compared to concentric and concentric morphology was more common in positive remodeling lesions than in negative.

15:00         3842.     Multistation Non-Contrast Black Blood Angiography for the Diagnosis of Peripheral Arterial Disease

Georgeta Mihai1, Yiu-Cho Chung2, Mbabazi Kariisa1, Jessica West1, Orlando P. Simonetti3,4, Sanjay Rajagopalan3

1Dorothy M Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA; 2Siemens Medical Solutions USA, Inc, Columbus, OH, USA; 3Cardiovascular Medicine, The Ohio State University, Columbus, OH, USA; 4Department of Radiology, The Ohio State University , Columbus, OH, USA

Contrast-enhanced angiography (ce-MRA) of the peripheral arteries allows evaluation of lumen stenosis but does not provide any information on atherosclerotic plaque burden. In this study we demonstrate that multistation dark blood high resolution imaging of the arteries can be performed rapidly, is at least as accurate as ce-MRA in evaluating lumen stenosis, and is capable of assessing atherosclerotic plaque deposition and vascular remodeling.

 
Exhibit Hall 2-3                    Thursday 13:30-16:00          Computer 47

13:30         3843.     Clinical Assessment of Motion Sensitized Driven Equilibrium (MSDE) Prepared T1W 3D Vessel Wall Imaging at 3.0T for Soft Plaque Screening

Makoto Obara1,2, Masatoshi Honda3, Yutaka Imai3, Marc Van Cauteren1, Kagayaki Kuroda2

1Philips Electronics Japan, Minato-ku, Tokyo, Japan; 2Graduate School of Information Science and Engineering, Tokai University, Hiratsuka, Kanagawa, Japan; 3Department of Radiology, Tokai University, Isehara, Kanagawa, Japan

Usefulness of a 3D turbo field echo (TFE) sequence with motion sensitized driven equilibrium (3D-MSDE-TFE) optimized for T1W carotid artery wall imaging was assessed in clinical practice. The sequence was compared with a conventional T1W 2D double inversion recovery turbo spin echo (2D-DIR-TSE) in five patients with soft plaque(s). The optimized sequence achieved T1 contrasts equivalent to those of the conventional one, while allowing larger spatial coverage without time penalty. Therefore, the optimized sequence may be appropriate for vessel wall screening.

14:00         3844.     T2 Mapping to Differentiate Slow Flowing Blood from Vessel Wall

Ryan Brown1, Thanh D. Nguyen1, Pascal Spincemaille1, Grace Choi1, Matthew D. Cham1, Priscilla A. Winchester1, Martin R. Prince1, Yi Wang1

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

Double inversion recovery (DIR) blood suppression is excellent when blood velocity is high but may be compromised when velocity is reduced as in the lower extremities. In this study, T2 mapping was utilized to distinguish artifactual partial blood signal from vessel wall signal at three vessel sites with different flow characteristics. We found that DIR blood suppression was sufficient in the aorta and common femoral artery but may be inadequate for vessel wall imaging in the popliteal artery where blood flow is typically reduced and triphasic, resulting in inflated vessel wall area and T2 relaxation measurements.

14:30         3845.     Negative Magnetic Resonance Contrast of Peri-Aortic Lymph Nodes Created by Uptake of Ultrasmall Superparamagnetic Particles of Iron Oxide (USPIOs) May Mask the Aortic Lumen and Lead to False Positive Results with Regard to the Diagnosis of Atherosclerosis.

Bernard C. te Boekhorst1, Sandra M. Bovens1,2, Marcel G. Nederhoff1,2, Kees W. van de Kolk1, Maarten J. Cramer1, Matthijs F. van Oosterhout3, Michiel ten Hove1, Pieter A. Doevendans1, Gerard Pasterkamp1, Cornelis J. van Echteld1

1Cardiology, University Medical Center Utrecht, Utrecht, Netherlands; 2InterUniversity Cardiology Institute of the Netherlands, Utrecht, Netherlands; 3Pathology, University Medical Center Utrecht, Utrecht, Netherlands

The strong T2* shortening effect of USPIOs leading to the effect of “glooming” and the uptake of USPIOs in lymph nodes adjacent to the aorta may pose limits to their use as contrast agent for visualization of atherosclerotic plaque in the aorta in animal models. We show a strong T2* and T2 effect of USPIOs uptaken in the para-aortic lymph nodes on MR images, which probably masks any effect of plaque uptake of USPIOs. With histology, when compared with lymph node uptake of USPIOs, hardly any uptake of USPIOs in plaque is observed 120 hours after administration.

15:00         3846.     Dynamic Contrast-Enhanced MRI Detects Progression of Inflammation in a Rabbit Model of Atherosclerosis

William Sean Kerwin1, Jerry Ricks2, Michael Rosenfeld2

1Radiology, University of Washington, Seattle, WA, USA; 2Pathology, University of Washington, Seattle, WA, USA

This study investiated the association of dynamic contrast-enhanced MRI measurements with macrophage content in experimental lesions of atherosclerosis at different time points in a rabbit model. We found a progressive increase that showed significant correlation with a corresponding increase in macrophage content.

 


 
Flow & Wall Motion
Exhibit Hall 2-3                    Monday 14:00-16:00          Computer 48

14:00         3847.     Detection of Time Delay for Aortic Compliance Evaluation

Yi Wang1,2, Jianping Zhang3, Edwin Estrada1, Jing Han1, Nathaniel Reichek1,2

1Research, St. Francis Hospital, Roslyn, NY, USA; 2Biomedical Engineering, SUNY, Stony Brook, NY, USA; 3Applied Mathematics and Statistics, SUNY, Stony Brook, NY, USA

Aortic pulse wave velocity, a measurement of the flow pulse traveling along aorta as a surrogate for aortic compliance, can be assessed using a single plane breath-hold phase contrast imaging technique. Accurate determination of the time delay (Δ;t) between flows in ascending and descending aorta is critical. Various approaches have been studied for & Δ;t, including measuring the intervals between flow onset points, between maximal flow points, and between parallel upslopes after least squares fittings. We compared four automated approaches for time delay detection and evaluated their effects on aortic compliance and their relationship to age in normal volunteers.

14:30         3848.     The Pulmonary Blood Volume Varies Throughout the Cardiac Cycle in Healthy Subjects – a Novel Method for Quantification by MRI

Martin Ugander1, Erik Jense1, Hakan Arheden1

1Clinical Physiology, Lund University Hospital, Lund, Sweden

The pulmonary blood volume varies during the cardiac cycle, but measuring this variation has been either cumbersome or of limited accuracy. This study shows that it is feasible to use MRI flow measurements to quantify the change in pulmonary blood volume during the cardiac cycle. The pulmonary blood volume in healthy volunteers increases on average just under 50 ml during systole and this was approximately 45% of the stroke volume. Further studies are needed to assess the utility of the pulmonary blood volume variation as a measure for identifying cardiac and/or pulmonary vascular disease.

15:00         3849.     Optimized Data Analysis for the Assessment of Aortic Pressure Difference Maps

Jelena Bock1, Alex Frydrychowicz1, Kevin Michael Johnson2, Oliver Wieben2, Jürgen Hennig1, Michael Markl1

1Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany; 2Medical Physics, University of Wisconsin, Madison, WI, USA

Flow sensitive 4D MRI permits the measurements of three directional blood flow velocities. The acquired data can be used for analysis of blood flow as well as to derive additional information on vessel geometry by time-averaged 3D phase contrast angiography. The derived vessel boundaries are useful for calculation of cardiovascular pressure gradients, which are an important clinical marker for the evaluation of the severity of disease.

15:30         3850.     Interactive Visualization and Analysis of Complex Flow Patterns in Congenital Heart Disease

Ben Landgraf1, Christopher J. Francois1, Oliver Wieben2, Elizabeth Janus Nett2, Kevin M. Johnson2

1Radiology, University of Wisconsin - Madison, Madison, WI, USA; 2Medical Physics, University of Wisconsin - Madison, Madison, WI, USA

With the availability of accelerated 4D velocity mapping, comprehensive information on the vascular anatomy and cine velocity fields can be obtained. In addition, hemodynamic parameters such as pressure differences and wall shear stress can be derived from those measurements. While this approach offers extensive information, it also poses significant challenges for data visualization and analysis in clinical practice. Here we present our experience in adapting a commercial engineering visualization package to address the unmet need of a comprehensive visualization for these multi-dimensional data for patients with congenital heart disease.

 
Exhibit Hall 2-3                    Tuesday 13:30-15:30          Computer 48

13:30         3851.     Blood Flow in the Healthy Aorta: Turbulent or Not?

Aurelien F. Stalder1, Alex Frydrychowicz1, Max F. Russe1, Jan G. Korvink2, Jürgen Hennig1, Michael Markl1

1Dept. of Diagnostic Radiology - Medical Physics, University Hospital, Freiburg, Germany; 2Dept. of Microsystems Engineering, University of Freiburg, Germany

Turbulence and velocity fluctuations of the blood flow are believed to play a role in hemolysis, platelet activation and thrombus formation. Based on flow-sensitive MRI, Reynolds, Womersley & Strouhal numbers have been measured in-vivo at 8 planes along the thoracic aorta in 30 healthy volunteers. The measurements were integrated in a turbulence model for pulsatile flow in order to assess the presence of turbulence in the healthy aorta. While turbulence-free regimes were observed in the aortic arch, onsets of turbulence were observed at peak systole in the ascending and descending aorta.

14:00         3852.     Improved Aortic Pulse Wave Velocity Assessment with Inplane Velocity-Encoded MRI: Validation and Reproducibility

Jos J.M. Westenberg1, Dennis Hendriksen1, Paul Steendijk2, Rob J. van der Geest1, Heynric B. Grotenhuis1, Maarten Groenink3, J W. Jukema2, Albert de Roos1, Johan H.C. Reiber1

1Radiology, Leiden University Medical Center, Leiden, Netherlands; 2Cardiology, Leiden University Medical Center, Leiden, Netherlands; 3Cardiology, Academic Medical Center, Amsterdam, Netherlands

An improved method to determine the aortic Pulse Wave Velocity with 2-directional inplane velocity-encoded MRI is presented. The accuracy of this method is tested in 15 patients by comparing MRI with invasive pressure measurements (ie. the gold standard for Pulse Wave Velocity-assessment). The reproducibility of the method is tested by repeated acquisition in 15 healthy volunteers. The new method shows excellent agreement with the gold standard and is highly reproducible, whereas the conventional MRI-method (1-directional through-plane MRI) agrees less with the gold standard and shows more variation.

14:30         3853.     Three-Dimensional Assessment of Wall Shear Stress Distribution in the Atherosclerotic Aorta

Andreas Harloff1, Andrea Nußbaumer1, Simon Bauer2, Aurelien F. Stalder2, Alex Frydrychowicz2, Cornelius Weiller1, Jürgen Hennig2, Michael Markl2

1Neurology, University Hospital Freiburg, Freiburg, Germany; 2Diagnostic Radiology, MR Physics, University Hospital Freiburg, Freiburg, Germany

Flow sensitive MRI for the in-vivo quantification of 3D blood-flow and derived vessel wall parameters may provide an enhanced understanding of flow-mediated arterial atherogenesis in the aorta. We sought to evaluate the individual distribution of segmental wall shear stress in 58 acute stroke patients. Time-resolved 3D phase contrast MRI with three-directional velocity encoding (flow-sensitive 4D MRI) was used to acquire the full hemodynamic information on 3D blood flow in the aorta. Optimized data quantification was used to derive segmental wall shear parameters covering the entire thoracic aorta.

15:00         3854.     Assessment of Asymmetric Aortic Distention Using Balanced Transient Field Echo MR Imaging

Joffrey van Prehn1,2, Koen L. Vincken1, Joost A. van Herwaarden2, Sara M. Sprinkhuizen1, Max A. Viergever1, Frans L. Moll2, Lambertus W. Bartels1

1Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands; 2Department of Vascular Surgery, University Medical Center Utrecht, Utrecht, Netherlands

We have implemented a scan sequence and ellipse fit post-processing technique that allow us to study the distension and the asymmetric aspect of the aortic expansion during the cardiac cycle. Healthy volunteers were scanned and the accuracy of the method was assed by a digital model of a pulsatile aorta with various levels of distension and asymmetric expansion. The current study demonstrates the feasibility of our method and shows that we can accurately detect and quantify asymmetry in the aortic distension. In vivo experiments demonstrated that the aortic expansion in the abdominal aorta of healthy volunteers is asymmetrical.

 
Exhibit Hall 2-3                    Wednesday 13:30-15:30          Computer 48

13:30         3855.     3D Flow Characteristics in a Patient Specific Aortic Aneurysm Vessel Model: Comparison with In-Vivo Results.

Ramona Lorenz1, Jelena Bock1, Aurélien F. Stalder1, Christoph Benk2, Jürgen Hennig1, Michael Markl1

1Dept. of Diagnostic Radiology, University Hospital, Freiburg, Germany; 2Dept. of Cardiovascular Surgery, University Hospital, Freiburg, Germany

Flow sensitive 4D MRI offers the ability to assess anatomy and flow characteristics in healthy and pathological blood vessels and is a promising tool for the diagnosis of vascular diseases. However, in-vivo studies do not allow the prediction of hemodynamic changes due to vascular modifications. Realistic vascular in-vitro phantoms in combination with MRI flow measurements allow to model different vascular deformations and evaluate their effect on flow dynamics. In this study in-vivo 3D flow characteristics in a patient with an ascending aortic aneurysm were compared to flow measured in a realistic in-vitro vessel model developed from the patient's aortic anatomy.

14:00         3856.     Visualization and Quantification of 3D Flow Characteristics in the Portal Venous System

Zoran Stankovic1, Alex Frydrychowicz1, Aurelien Stalder1, Jelena Bock1, Elisabeth Panther2, Maximilian Russe1, Juergen Hennig1, Mathias Langer1, Michael Markl1

1Department of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Baden Württemberg, Germany; 2Department of Gastroenterology, University Hospital Freiburg, Freiburg, Baden Württemberg, Germany

3D MR velocity mapping at 3T visualized, for the first time, the comprehensive 3D flow characteristics in the portal venous system. The feasibility of the 3D visualization and quantitative basement of portal venous hemodynamics was evaluated in a study with 18 healthy volunteers.

14:30         3857.     Perfusion MRI for Monitoring Therapy Effects in Experimental Chronic Limb Ischemia

Harald Kramer1, Steven Sourbron1, Rabea Hinkel2, Franziska Globisch2, Christian Kupatt-Jeremias2, Maximilian F. Reiser1, Bernd J. Wintersperger1

1Institute for Clinical Radiology, University Hospital Munich, Munich, Germany; 2Department for Cardiology, University Hospital Munich, Munich, Germany

Angiographic techniques such as DSA, CTA or MRA are limited to the display of macroscopic vasculature only. New therapeutic regimens in peripheral artery disease that are currently under investigation though may result in substantial differences in limb perfusion only due to changes at the microvascular level, which can only be readily displayed by perfusion imaging. Because of the non-invasiveness and the lack of ionizing radiation MRI seems to be an ideal method for perfusion imaging. Initial data indicate that perfusion MRI provides a useful tool for the evaluation of peripheral ischemia and for monitoring of therapeutic effects.

15:00         3858.     4D Spiral Phase-Contrast MRI of Wall Shear Stress in the Mouse Aorta

Robert L. Janiczek1, Craig H. Meyer1,2, Scott T. Acton1,3, Brett R. Blackman1, Frederick H. Epstein1,2

1Biomedical Engineering, University of Virginia, Charlottesville, VA, USA; 2Radiology, University of Virginia, Charlottesville, VA, USA; 3Electrical Engineering, University of Virginia, Charlottesville, VA, USA

Atherosclerosis is a focal inflammatory disease of the vessel wall believed to be influenced by local hemodynamic forces such as wall shear stress (WSS). A 4D spiral phase contrast MRI sequence was developed and used for measuring WSS throughout the mouse aortic arch. Short spiral readouts, variable density spirals, and k-space trajectory measurement correction enabled measurement of the entire hemodynamic environment in the mouse aortic arch. The spatial distribution of WSS showed higher WSS values near the outer radius, an atheroprotective region, and lower WSS values near the inner radius of the aortic arch, an atheroprone region.

 
Exhibit Hall 2-3                    Thursday 13:30-15:30          Computer 48

13:30         3859.     MR-Driven Computational Fluid Dynamics

Jon-Fredrik Nielsen1, Krishna S. Nayak2

1Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA; 2Electrical Engineering, University of Southern California, Los Angeles, CA

In-vivo blood flow is typically assessed by 3D phase-contrast MRI, or by Computational Fluid Dynamics (CFD) calculations. MRI measurements are direct, but offer limited spatio-temporal resolution. Conventional CFD calculations offer "infinite" spatial resolution, but rely on the accuracy of the assumed fluid properties and boundary conditions. We propose a hybrid MRI/CFD approach that integrates low-resolution MRI flow measurements directly into the CFD solver. We show that MR-driven CFD has a regularizing effect on the flow fields obtained with MRI alone, and produces flow patterns that are in better agreement with direct MRI measurements than CFD alone.

14:00         3860.     4D Flow Evaluation of Abnormal Systolic Flow Patterns with Bicuspid Aortic Valve

Michael D. Hope1, Thomas A. Hope1, Alison K. Meadows1, Karen G. Ordovas1, David Saloner1, Marcus T. Alley2, Charles B. Higgins1

1Radiology, UCSF, San Francisco, CA, USA; 2Radiology, Stanford, Palo Alto, CA, USA

Abnormal systolic helical flow is seen with 4D Flow in the ascending thoracic aorta of patients with bicuspid aortic valve. Similar helical flow has been described in ascending aortic aneurysms associated with BAV, but we have demonstrated this flow pattern in three patients without aneurysm, suggesting that the pattern is not secondary to the dilated aorta, but may be implicated in the pathogenesis of aneurysm formation. The marked helical flow in the ascending aorta appears to be associated with eccentric flow jets in all 9 of our cases. Identification and characterization of eccentric flow jets in patients with BAV may help risk stratify for development of ascending aortic aneurysm and dissection.

14:30         3861.     Extending 4D Flow Visualization to the Human Right Ventricle

Petter Dyverfeldt1, Jonatan Eriksson1, Andreas Sigfridsson1, John-Peder E. Kvitting1, Carljohan Carlhäll1, Jan Engvall1, Ann F. Bolger2, Tino Ebbers1

1Linköping University and Center for Medical Image Science and Visualization (CMIV), Linköping, Sweden; 2University of California San Francisco, San Francisco, CA, USA

The right ventricle has an important role in cardiovascular disease. However, because of the complex geometry and the sensitivity to the respiratory cycle, imaging of the right ventricle is challenging. We investigated whether 3D cine phase-contrast MRI can provide data with sufficient accuracy for visualizations of the 4D blood flow in the right ventricle. Whole-heart 4D flow measurements with optimized imaging parameters and post-processing tools were made in healthy volunteers. Pathlines emitted from the right atrium could be traced through the right ventricle to the pulmonary artery without leaving the blood pool and thereby met our criteria for sufficient accuracy.

15:00         3862.     Reconstruction of Aortic Blood Flow Pattern After Thoracic Stent Graft Implantation

Volker Rasche1, Gerard R. Crelier2, Axel Bornstedt1, Martin Hoffmann3, Alexander Oberhuber4, Ludger Sunder-Plassmann4

1Internal Medicine II, University Ulm, Ulm, Germany; 2GyroTools GmbH, Winterthur, Switzerland; 3Radiology, University Ulm, Ulm, Germany; 4Thorax and Vascular Surgery, University Ulm, Ulm, Germany

Three-dimensional quantitative aortic flow pattern were assessed in patients after Thoracic Endovascular Aortic Repair (TEVAR).

 


 
Time-Resolved MRA
Exhibit Hall 2-3                    Monday 14:00-16:00          Computer 49

14:00         3863.     Dynamic Contrast Enhanced MR Angiography (4D MRA) Ot the Thoracic Vessels - An Intravidual Comparison of Different K-Space Acquisition Strategies

Florian M. Vogt1, Katja Seng2, Peter Hunold1, Stefan Maderwald2, Armin deGreiff2, Gerhard Laub3, Jörg Barkhausen1

1Radiology and Nuclear Medicine, University Hospital Schleswig-Holstein, Lübeck, Schleswig-Holstein, Germany; 2University Hospital Essen; 3Siemens Medical Solutions at University of California

Purpose was to evaluate different k-space acquisition protocols for dynamic 3D-MRA of thoracic vessels and to assess intra-individually their influence on image quality, artifacts and contrast enhancement while keeping temporal and spatial resolution constant. In 20 patients two TWIST protocols with different k-space acquisition strategies were performed on a 1.5 T whole-body scanner. The high spatial and temporal resolution of the TWIST sequence allowed sufficient morphological and functional assessment of the aorta and pulmonary arteries but with significant better results using protocol 1. Keeping spatial and temporal resolution constant the strategy of k-space acquisition has relevant influence on image quality.

14:30         3864.     Combining Sensitivity Encoding (SENSE) and Foldover Suppression to Overcome FOV Restrictions in Thoracic 3D CE-MRA

Varaha Satya Sairam Tammisetti1, Silke Potthast2, Theodore J. Dubinsky2, Gregory J. Wilson3,4, Jeffrey Harold Maki2,5

1 Diagnostic and Interventional Imaging, University of Texas HSC, Houston, TX, USA; 2Radiology, University of Washington, Seattle, WA, USA; 3Philips Healthcare, Cleveland, OH, USA; 4Radiology, University of Washington, Seattle, WA, USA; 5Radiology, Puget Sound VAHCS, Seattle, WA, USA

 

15:00         3865.     Time-Resolved MR Angiography in Evaluation and Mapping of Central Thoracic Veno-Occlusive Disease

Kambiz Nael1, Stefan G. Ruehm1, Mayil Krishnam1, Gerhad Laub2, J Paul Finn1

1Radiological Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; 2Siemens, Los Angeles, CA, USA

Using time-resolved angiography with interleaved stochastic trajectories (TWIST) and parallel acquisition can improve the performance of time-resolved MRA. Our results demonstrate that TR-MRA with a high comparable sensitivity, and need for only a small gadolinium dose (6ml), has the potential to be used as an initial and screening diagnostic tool in assessment of central venous occlusive disease, obviating the need for conventional MRA and higher contrast dose in normal or near-normal examination. However, due to relatively lower specificity of TR-MRA, adjunct use of conventional CE-MRA is still required for accurate grading of venous occlusive disease.

15:30         3866.     Fat-Suppressed Non-Contrast-Enhanced MR Angiography of Thorax: Comparison Between Navigator-Gated SSFP and Respiratory-Gated TSE Imaging

Yasuo Amano1, Katsuya Takahama1, Yoshio Matsumura1, Shinichiro Kumita1

1Radiology, Nippon Medical School, Tokyo, Japan

Two non-contrast-enhanced 3D MR angiography techniques of the thorax were compared: navigator-gated SSFP and respiratory-gated TSE. Fat-suppression and ECG gating were employed for both sequences. The 3D SSFP provided more homogenous vascular signal of aortic root and better visualization of coronary arteries with shorter scan time, and thus this imaging sequence may be the first choice of non-contrast-enhanced 3D MR angiography of thorax. The respiratory-gated 3D TSE can be a good alternative to the 3D SSFP when the fat-suppression inappropriately reduces vascular signals or patients complain of upper extremity ischemia, because of its less artifacts around the left subclavian artery.

 
Exhibit Hall 2-3                    Tuesday 13:30-15:30          Computer 49

13:30         3867.     Leading Edge Fidelity in View-Shared Time-Resolved 3D MRA

Petrice Marie Mostardi1, Clifton Haider1, Philip Rossman1, Stephen Riederer1

1Mayo Clinic, Rochester, MN, USA

Artifactual signal enhancement in a vessel occurring in advance of actual contrast arrival can misrepresent the underlying contrast bolus dynamics. The purpose of this work is to show how the “anticipation” artifact occurring in advance of the contrast bolus leading edge can be minimized with appropriate ordering of phase encoding views. This is demonstrated experimentally in phantoms and with in vivo CE-MRA. Reconstructing time-resolved data sets using predominantly high spatial frequency data acquired before the central k-space region for that update allows for decreased anticipation artifact and more accurate depiction of the contrast bolus leading edge.

14:00         3868.     Intraindividual Comparison of Contrast Enhanced Magnetic Resonance Angiography and Digital Subtraction Angiography of the Lower Extremities

Johannes T. Heverhagen1, Michael Augsten1, Michael Burbelko1, Anna-Christina Stamm1, Marc O. Kalinowski1, Klaus Klose1

1Department of Diagnostic Radiology, Philipps University, Marburg, Germany

The purpose of this study was to intraindividually compare CE MRA and DSA of the lower extremities in patients with severe peripheral arterial occlusive disease (PAOD). State of the art run off MRA of the lower extremities for suspected PAOD provides excellent sensitivity and specificity. It is user independent proven by a Cohen´s kappa of 0.88. State of the art run off MRA of the lower extremities may replace diagnostic DSA for suspected PAOD as an user independent, accurate application.

14:30         3869.     Peripheral Contrast-Enhanced MR Angiography Using a SNR and Timing Optimized Protocol: Evaluation of Patient Lower Extremity Hemodynamics in 48 Patients

Earl Michael Chester1, George R. Oliveira1, Gregory J. Wilson1,2, Jeffrey Harold Maki1,3

1Radiology, University of Washington, Seattle, WA, USA; 2Philips Healthcare, Cleveland, OH, USA; 3Radiology, Puget Sound VAHCS, Seattle, WA, USA

This is a retrospective study examining arterial and venous hemodynamics in an optimized three-station moving-table peripheral contrast-enhanced MR angiography technique applied to 48 patients being evaluated for PVOD. This study found no significant difference in average aorta-foot arterial or aorta-to-lower extremity venous contrast arrival time between claudication patients with and without diabetes mellitus, or between claudicants and those with peripheral ulcers. There was, however, a significant difference in lower extremity venous enhancement (p=0.044) between patients with claudication and those with peripheral ulcers. This study demonstrates the difficulty in predicting venous contrast arrival without a priori knowledge of patient-specific timing parameters.

15:00         3870.     Continuous Table Movement for Peripheral MRA with Matrix Coils at 3.0T

Harald Kramer1, Peter Schmitt2, Michael Zenge2, Christian Glaser1, Maximilian F. Reiser1, Karin A. Herrmann1

1Institute for Clinical Radiology, University Hospital Munich, Munich, Germany; 2Siemens AG

MRA with continuous table movement is an easy applicable technique for imaging peripheral vessels without the need for planning different steps and FOV positioning, thus examination time can be reduced considerably. However, the reduced spatial resolution compared to standard step-by-step MRA is a drawback especially in the most distal calf vessels which leads to under- or overestimation of findings. New data acquisition techniques help to overcome the technical limitations present today.

 
Exhibit Hall 2-3                    Wednesday 13:30-15:30          Computer 49

13:30         3871.     Comprehensive Magnetic Resonance Evaluation of Vascular Malformations at 3T: Comparison of Time-Resolved Angiography with Interleaved Stochastic Trajectories (TWIST) with Standard 3D Contrast Enhanced MR Angiography (CeMRA)

Ehab Ahmed Abdel-Gawad1,2, Patrick T. Norton1, Ahmed Mohamed Housseini1,3, Ismaeel Mohammad Maged1,3, klaus D. Hagspiel1

1Department of Radiology, University of Virginia Health System, Charlottesville, VA, USA; 2Department of Radiology, El Minya University, El Minya, Egypt; 3Department of Radiology, Suez Canal University, Ismailia, Egypt

MRI has an important role in categorizing vascular malformations as low-flow or high-flow and determining their extent. TWIST is a high temporal resolution time resolved MRA technique which potentially allows for differentiation of flow states. Five patients with vascular malformations were examined with at 3T with TWIST and standard ceMRA. The introduction of the TWIST sequence increased ability to characterize flow patterns related to the malformation as compared to ceMRA and greatly helps in treatment planning.

14:00         3872.     Dedicated Calf MRA at 3T: Comparison of Time-Resolved MR Angiography with Interleaved Stochastic Trajectories (TWIST) with Standard High-Resolution 3D Contrast Enhance MR Angiography (HR CeMRA)

Ismaeel M. Maged1,2, Patrick T. Norton1, Ugur Bozlar1,3, Ehab A. Abdel-Gawad1,4, Ahmed Mohamed Housseini1,2, Kenneth J. Cherry5, Klaus D. Hagspiel1

1Department of Radiology, University Of Virginia Health System, Charlottesville, VA, USA; 2Department of Radiology, Suez Canal University, Ismailia, Egypt; 3Department of radiology, Gulhane Military Medical Academy, Etlik, Ankara, Turkey; 4Department of Radiology, El Minya University, El Minya, Egypt; 5Department of Surgery, University Of Virginia Health System, Charlottesville, VA, USA

HR ceMRA is excellent in diagnosing peripheral arterial disease with a limitation of venous contamination in the calf station. TWIST allows good discrimination between arterial and venous enhancement. Diagnostic performance of TWIST and HR ceMRA were compared in 8 patients at the calf station. TWIST and HR ceMRA perform similarly at 3T, except for the distal calf were TWIST overestimates stenosis. A combined MR imaging protocol both techniques provides a robust approach to the assessment of peripheral artery disease that would not be limited by venous contamination.

14:30         3873.     Time Resolved Peripheral MRA: Correlation with Functional Lower Limb Impairment.

Aoife N. Keeling1, Cormac Farrelly1, John Sheehan1, William Pearce2, Timothy J. Carroll3, Mary M. McDermott4, James C. Carr1

1Dept of Cardiovascular Imaging, Northwestern Memorial Hospital, Chicago, IL, USA; 2Department of Vascular Surgery, Northwestern Memorial Hospital, Chicago, IL, USA; 3Dept of Cardiovascular Imaging, Dept of Biomedical Engineering, Northwestern Memorial Hospital, Chicago, IL, USA; 4Department of Preventative Medicine, Northwestern Memorial Hospital, Chicago, IL, USA

Peripheral arterial disease (PAD) severity, as assessed by ankle brachial index (ABI), significantly correlates with the degree of functional impairment. However, a correlation between the severity of PAD, as determined by time resolved magnetic resonance angiography (MRA), and functional limb impairment has not been determined. 58 patients with known PAD had time resolved MRA performed using a TWIST sequence on a 1.5T Siemens Espree MRI scanner, with single dose Magnevist. Time resolved peripheral magnetic resonance angiographic lesion severity and collateral grade significantly correlates with lower limb functional impairment in patients with PAD.

15:00         3874.     Time-Resolved MRA Using Sliding Window Reconstruction for Evaluation of Renal Arterial Anatomy and Perfusion.

Aoife N. Keeling1, Ravi K. Singh1, Cormac Farrelly1, Hyun Jeong2, Ty A. Cashen3, John Sheehan1, James C. Carr1, Timothy J. Carroll4

1Dept of Cardiovascular Imaging, Northwestern Memorial Hospital, Chicago, IL, USA; 2Dept of  Biomedical Engineering, Northwestern Memorial Hospital, Chicago, IL, USA; 3Dept of Biomedical Engineering, Northwestern Memorial Hospital, Chicago, Ilinois, USA; 4Dept of Cardiovascular Imaging, Dept of Biomedical Engineering, Northwestern Memorial Hospital, Chicago, IL, USA

Time-resolved contrast enhanced magnetic resonance angiography, can provide arterial anatomical and pathological detail, but can also follow the first pass of contrast through visceral parenchymal tissue in order to evaluate vascular flow dynamics or perfusion. We hypothesize that dynamic mask-mode subtraction yields perfusion weighted images of the renal parenchyma with a single doe of Gadolinium. Eleven healthy volunteers and one renal transplant patient were recruited to undergo MRI examination using a radial three-dimensional FLASH acquisition with sliding window view-share reconstruction on a 1.5T Siemens MRI scanner. The technique produced diagnostic quality angiographic images and perfusion maps in all.

 
Exhibit Hall 2-3                    Thursday 13:30-15:30          Computer 49

13:30         3875.     Contrast-Enhanced Magnetic Resonance Angiography (CE-MRA) for Detection of Reperfused Pulmonary Arteriovenous Malformations (PAVM) After Coil Embolization in Patients with Hereditary Hemorrhagic Telangiectasia (HHT)

Guenther Schneider1, Alexander Massmann2, Peter Fries2, Marcus Katoh2, Urban Geisthoff3, Arno Buecker2

1University Hospital of Saarland, Homburg / Saar, Germany; 2University Hospital of Saarland, Germany; 3Clinics of City of Cologne/Holweide, Germany

Hereditary hemorrhagic telangiectasia (HHT), also known as Rendu-Osler-Weber disease, is an autosomal-dominant inherited vascular disorder associated with mucocutaneous, pulmonary, cerebral and visceral arteriovenous malformations (AVM). Pulmonary arteriovenous shunts (PAVM) are associated with high morbidity and mortality. The primary choice of treatment of PAVMs is catheter embolization with platinum coils, which is technically safe and effective. However, even in an initial successful occlusion, there may be a reperfusion of embolized feeding vessels or opening of collateral vessels. This study shows that contrast-enhanced magnetic resonance angiography (CE-MRA) is a useful tool for follow-up examinations of treated PAVMs, in which platinum coils were used for embolization, preferable to CT and even global pulmonary catheter angiography.

14:00         3876.     Time-Resolved MR Angiography for Assessment of Pulmonary Hypertension in Patients with Congenital Heart Disease

Amir Hossein Davarpanah1, John J. Sheehan1, Timothy J. Carroll2, James C. Carr2

1Department of Radiology , Northwestern University, Feinberg School of Medicine, Chicago, IL, USA; 2Department of Radiology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA

Pulmonary hypertension remains a major mortality factor of many types of congenital heart disease. Cardiopulmonary transit time as measured by time-resolved MR angiography, is significantly prolonged in congenital heart disease patients complicated with pulmonary hypertension and correlates well with ventricular volumetric indices of right heart failure. These measurements may provide a useful adjunct tool for assessing and following pulmonary hypertension and early right-sided heart failure in this group of patients.

14:30         3877.     Comprehensive Magnetic Resonance Imaging of the Hand and Forearm Vasculature at 3 Tesla Using Time-Resolved Angiography with Stochastic Trajectories (TWIST): Preliminary Clinical Results

Thomas Efren Huerta1, Patrick T. Norton1, B Chhabra2, D B. Drake3, P B. Arnold3, Ahmed Mohamed Housseini1,4, Klaus D. Hagspiel1

1Department of Radiology, University of Virginia Health System, Charlottesville, VA, USA; 2Department of Orthopaedics, University of Virginia Health System, Charlottesville, VA, USA; 3Department of Plastic Surgery, University of Virginia Health System, Charlottesville, VA, USA; 4Department of Radiology, Suez Canal University, Ismailia, Egypt

The advent of 3T MR has improved imaging of the small vessels of the hand but still suffers from limitation of temporal resolution for assessing flow dynamics. We evaluated an imaging protocol combining TWIST and VIBE for the assessment of vascular pathology, building on our previous work with standard time resolved MRA.

15:00         3878.     High Resolution Non Contrast Enhanced MRA of the Hand Arteries at 3 Tesla Using an ECG-Triggered Variable Flip Angle 3D Fast Spin Echo (SPACE) Sequence

Ruth P. Lim1, Pippa Storey1, Iliyana P. Atanasova1, Jian Xu2, elizabeth m. Hecht1, David R. Stoffel1, Hugo Chang2, Kellyanne Mcgorty1, qun Chen1, henry Rusinek1, H Michael Belmont3, Vivian S. Lee1

1Radiology, NYU Langone Medical Center, New York, USA; 2Siemens Medical Solutions, New York, USA; 3Rheumatology, NYU Langone Medical Center, New York, USA

Slow arterial flow, small vessel caliber and short arteriovenous transit times make hand MRA challenging. We present our initial experience with an ECG-triggered variable flip angle 3D fast spin echo (SPACE) MRA technique at 3T in 9 subjects. Two volunteers also underwent assessment of vascular reactivity, with MRA obtained following cooling. Two radiologists in consensus evaluated image quality and vessel visualization. Image quality was generally excellent or satisfactory, with high vessel conspicuity, including visualization of the distal digital arteries. Following cooling challenge, fewer vessel segments were visualized and were of smaller caliber.

 


 
Contrast Enhanced MRA
Exhibit Hall 2-3                    Monday 14:00-16:00          Computer 50

14:00         3879.     Dynamics of Contrast Agents in MRA: Analytical Basis and Experimental Validation

Abbas Nasiraei Moghaddam1,2, Tariq Balawi1, Reza Habibi1, Gerhard Laub3, J. Paul Finn1

1Radiology, UCLA, Los Angeles, CA, USA; 2Bioengineering, Caltech, Pasadena, CA, USA; 3Siemens Medical Solution, USA

The quality of MR angiography (MRA) images depends on synchronizing data acquisition with arrival of the contrast bolus in the vessels of interest. In this study we analytically verify that the circulatory system can be modeled as a linear time-invariant system that responds linearly to the infusion as its input. We further show how such a system may be characterized based on physiological parameters. This approach was experimentally quantified for MRA by implementing a software tool. The implemented algorithm as well as the signal enhancement in the high-resolution MRA, predicts stable “85% peak periods” for carotid and venous signals.

14:30         3880.     Potential Bias on Measurement of Atherosclerotic Stenosis: The Implication from Calibrations at Various Positions Along Arteries

Kai Lin1,2, Zhao-qi Zhang1, Biao Lu1, Zhan-ming Fan1

1Radiology, Beijing Institute of Heart Lung and Blood Vessel Diseases& Beijing Anzhen Hospital, Beijing, China; 2Radiology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA

On CE-MRA and CTA of health volunteers, we retrospectively measured diameter of coronary and carotid artery at 0cm, 1cm, 2cm, 3cm, 4 cm and 5cm along the vessel from the origin. The results showed that calibrations (represented as percentage of calibration at the origin) of distal parts decease gradually and greatly from the origin, especially in the carotid artery. We suggest that different parts selected as reference should be seriously taken account into calculation for atherosclerotic stenosis, especially when NASCET criteria is used.

15:00         3881.     Validation of 3D-CEMRA with 2D ARC Acceleration in a Porcine Study

Christopher J. François1, Mark L. Schiebler1, Scott B. Reeder1, Oliver Wieben2, Reed F. Busse3, Jean H. Brittain3, Thorsten A. Bley1

1Radiology, University of Wisconsin, Madison, WI, USA; 2Medical Physics, University of Wisconsin, Madison, WI, USA; 3MR Applied Science Laboratory, GE Healthcare, Madison, WI, USA

This work presents validation of an accelerated, volumetric contrast-enhanced magnetic resonance angiography (CEMRA) technique for evaluating surgically induced renal artery stenosis (RAS) in an animal model. The CEMRA sequence described in this study uses a 2D parallel imaging acceleration method (auto-calibrating reconstruction for Cartesian sampling, “ARC”) to provide near 4-fold accelerations. As a result, high resolution CEMRA of the entire abdomen can be obtained within a single breath-hold. The results of CEMRA were compared with the gold standard, DSA, and confirm the accuracy of CEMRA with 2D ARC acceleration for grading the severity of RAS.

15:30         3882.     In Vivo 3D MR Angiography Reveals Accelerated Collateral Vessel Growth in CD73-/-  Mice After Hindlimb Ischemia

Ulrich Flögel1, Yang Chul Böring2, Christoph Jacoby, Jürgen Schrader

1Institut für Herz- und Kreislaufphysiologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, NRW, Germany; 2Institut für Herz- und Kreislaufphysiologie, Heinrich-Heine-Universität Düsseldorf, Germany

Therapeutic neovascularization via the processes of angiogenesis and arteriogenesis is a promising new approach for the treatment of ischemia. Adenosine is a potent stimulator of angiogenesis, however, its role in arteriogenesis is not known. We therefore have investigated whether adenosine formed extracellularly by CD73 (ecto-5’-nucleotidase) influences arteriogenesis in a hindlimb ischemia model. Serial comparison of blood flow recovery and direct visualization of newly developed collateral vessels in wild-type and CD73-/- mice by high resolution 3D MR angiography revealed enhanced arteriogenesis in mice lacking CD73 and concomitantly improved metabolic recovery after ischemia by 31P MR spectrocopy.

 
Exhibit Hall 2-3                    Tuesday 13:30-15:30          Computer 50

13:30         3883.     Optimisation of the Contrast Dose and Injection Rates in Whole Body Angiography at 3T

Shelley A. Waugh1, Stephen J. Gandy1, R Stephen Nicholas1, Prasad Guntur Ramkumar2, Baljit Jagpal2, J Graeme Houston2

1Medical Physics, Ninewells Hospital, Dundee, Angus, UK; 2Clinical Radiology, Ninewells Hospital, Dundee, Angus, UK

The aim of this study was to optimise the contrast dose and injection rate for whole body angiography (WBA) imaging at 3T. Six groups of asymptomatic volunteers underwent WBA, each receiving a different contrast injection protocol.

14:00         3884.     Accelerated 3D Time-Resolved MR Angiography Using Cartesian HYPR LR Reconstruction

Kang Wang1, Jiang Du2, Yijing Wu1, Reed F. Busse3, Kevin M. Johnson1, Frank R. Korosec1,4

1Medical Physics, University of Wisconsin-Madison, Madison, WI, USA; 2Radiology, University of California, San Diego, San Diego, CA, USA; 3Applied Science Laboratory, GE Healthcare, Madison, WI, USA; 4Radiology, University of Wisconsin-Madison, Madison, WI, USA

Simultaneous achievement of high spatial and temporal resolution has always been a challenge in contrast-enhanced MR angiography (CE-MRA). Several k-space undersampling methods have been reported in literature, including radial sampling, spiral sampling and Cartesian-based undersampling approaches. Meanwhile, novel reconstruction methods have been developed to exploit the temporal-spatial correlation in CE-MRA, such as HYPR and HYPR LR. Here we present a Cartesian implementation of HYPR LR, which fits most Cartesian k-space undersampling schemes, and has great simplicity. The proposed method may have great potential for clinic applications.

14:30         3885.     Multicenter, Intraindividual Comparison of Gadobenate Dimeglumine and Gadopentetate Dimeglumine for MRA of the Peripheral Arteries

Tim Leiner1, Suzanne Gerretsen1, Thierry le Maire2, Stephan Miller3, Siegfried Thurnher4, Christoph U. Herborn5, Henrik Michaely6, Harald Kramer7, Angelo Vanzulli8, Josef Vymazal9, Martin Wasser10

1Department of Radiology, Maastricht University Hospital, Maastricht, Netherlands; 2Department of Radiology, Catharina Hospital, Eindhoven, Netherlands; 3Department of Diagnostic and Interventional Radiology, Eberhard-Karls University, Tübingen, Germany; 4Department of Radiology, Hospital of St. John's of God, Vienna, Austria; 5Medical Prevention Center, University Medical Center, Hamburg-Eppendorf, Germany; 6Department of Clinical Radiology, University Hospital Mannheim, Mannheim, Germany; 7Institute of Clinical Radiology, Ludwig Maximilians University, Munich, Germany; 8Radiologia, Ospedale Niguarda Ca' Granda, Milan, Italy; 9Department of Radiology,, Homolce Hospital, Prague, Czech Republic; 10Department of Radiology, Leiden University Medical Center, Leiden, Netherlands

This study intraindividually compared 0.1 mmol/kg bodyweight doses of gadobenate dimeglumine (MultiHance®; Gd-BOPTA) and gadopentetate dimeglumine (Magnevist®; Gd-DTPA) for contrast-enhanced MRA in 96 patients with peripheral arterial occlusive disease. Preference for Gd-BOPTA was expressed by each of three off-site blinded readers for all qualitative endpoints in each of three vascular territories. Likewise significantly (p≤0.0001) higher CNR was noted for Gd-BOPTA by each reader in each vascular territory. Overall, Gd-BOPTA at 0.1 mmol/kg demonstrated significantly better diagnostic performance compared to an equivalent dose of Gd-DTPA for CE-MRA of the peripheral vasculature.

15:00         3886.     High Resolution Peripheral CE-MRA Featuring Continuous Table Movement (TimCT) and K-Space Segmentation: Initial Results

Michael O. Zenge1, Sonja Kinner2, Anton S. Quinsten2, Harald H. Quick2

1MR Applications Development, Siemens AG, Healthcare Sector, Erlangen, Germany; 2Department of Diagnostic and Interventional Radiology, University Hospital Essen, Essen, Germany

Continuously moving table MRA enables the acquisition of seamless large FOV data with a significantly streamlined workflow. In contrast enhanced MRA the total acquisition time is conventionally restricted to the arterial time window. In the current work, continuously moving table data acquisition and reconstruction was combined with k-space segmentation such that the central region of k-space is acquired during the first-pass and the peripheral region was acquired during the late phase of the contrast agent. This method was successfully evaluated with 5 patients with known PAOD who underwent moving table MRA. The spatial resolution was increased while avoiding venous overlay.

 
Exhibit Hall 2-3                    Wednesday 13:30-15:30          Computer 50

13:30         3887.     Contrast-Enhanced MRA in the NSF Era: Potential for Contrast Dose Reduction

Matthew J. Kuhn1

1Radiology, Southern Illinois University School of Medicine, Springfield, IL, USA

Higher doses of gadolinium-based contrast agents are often required when performing MR angiography in order to achieve sufficient intravascular signal intensity. However, patients with moderate-to-severe CKD undergoing contrast-enhanced MR imaging are at increased risk for developing NSF, particularly with higher doses or repeated exposure to MR contrast agents. The results of 7 intraindividual crossover studies, in which the higher-relaxivity contrast agent gadobenate dimeglumine (Gd-BOPTA) is compared with conventional MR contrast agents for MRA in various vascular territories, demonstrate that Gd-BOPTA may be used at lower dose without compromise of diagnostic efficacy, potentially limiting patient exposure to contrast.

14:00         3888.     Reducing Gd Dose for Moving Table MRA Using Cine-PC to Map Bolus Transit

Grace Choi1, Priscilla Winchester1, Minh Chao1, Yi Wang1, Martin Raymond Prince1

1Radiology, Weill Cornell Medical College, New York, USA

Concern for NSF has motivated use of lower Gd doses in moving table MRA. To improve bolus timing at all stations of a moving table MRA and allow smaller shorter boluses, we used cine-PC at 6 locations to map the rate of blood flow down the aorta, iliac and femoral arteries. Testing methodology in 15 subjects and a prospective MRA trial in 6 subjects demonstrates excellent bolus timing achieved at all stations even when sharing only 0.1mMol/kg total Gd dose.

14:30         3889.     Comparison of Image Quality and Diagnostic Accuracy of 0.5 Molar Gadobenate Dimeglumine and 1.0 Molar Gadobutrol in Contrast-Enhanced Run Off MRA of the Lower Extremities

Johannes T. Heverhagen1,2, Marina Achenbach1, Jens Figiel1, Christoph Weiss1, Anna-Christina Stamm1, Klaus Klose1

1Department of Diagnostic Radiology, Philipps University, Marburg, Germany; 2Department of Radiology, The Ohio State University, Columbus, OH, USA

To compare image quality and diagnostic accuracy of 0.5 molar and 1.0 molar in contrast-enhanced run off MRA of the lower extremities in 74 patients. Application of a single dose gadobenate dimeglumine and a double dose gadobutrol in contrast-enhanced run off MRA of the lower extremities did not show any significant differences in image quality and diagnostic accuracy. Gadolinium dose could be reduced without a loss of image quality or diagnostic accuracy by the application of a single dose of gadobenate dimeglumine for CE run off MRA of the lower extremities.

15:00         3890.     LST-Based  Optimization of Patient Specific Contrast Media  Administration for CE-MRA: Validation Studies in Phantoms and Volunteers

Daniel Kopeinigg1,2, Dominik Fleischmann1, Rudolf Stollberger2, Roland Bammer1

1Stanford University, Palo Alto, CA, USA; 2University of Technology Graz, Graz, Austria

A LST-based optimization approach – as introduced last year -- uses a test bolus of contrast media to extract patient-specific physiological properties with the objective to compute an injection profile that results in a desired intravascular enhancement profile.

 
Exhibit Hall 2-3                    Thursday 13:30-15:30          Computer 50

13:30         3891.     Blood-Pool Imaging Properties of Non Protein-Binding Extracellular Unspecific Gadolinium-Based Contrast Media

Patrick Asbach1, Moritz Wagner1, Matthias Rief1, Matthias Taupitz1, Bernd Hamm1, Christian Klessen1

1Department of Radiology, Charité University Hospital, Berlin, Germany

The aim of the study was to investigate whether non protein-binding extracellular unspecific Gadolinium-based contrast media have a blood-pool effect that allows equilibrium phase MR angiography. 30 patients received either a protein-binding blood-pool contrast medium or a non protein-binding unspecific extracellular contrast medium. Quantitative signal intensity measurements and qualitative grading of vessel contrast were performed. Imaging was carried out up to 25 minutes after contrast injection. Non protein-binding unspecific extracellular Gadolinium-based contrast media have the potential of blood pool phase imaging within a time window of less than 15 minutes.

14:00         3892.     First-Pass Whole-Body Magnetic Resonance Angiography at 3T with the Blood-Pool Contrast Agent Gadofosveset and the Extracellular Contrast Agent Gadoterate: A Randomized Study.

Yousef Wirenfeldt Nielsen1

1Dept. of Radiology, Copenhagen University Hospital Herlev , Herlev, Denmark

Whole-body magnetic resonance angiography (WB-MRA) can depict arterial stenoses in a large part of the body in one fast examination. We investigated the feasibility of 3T WB-MRA using the built-in body coil for signal acquisition. Two different contrast agents (a standard extracellular agent and a blood-pool agent) were used in a randomized manner. A total of 16 patients with symp-tomatic peripheral arterial disease were examined. DSA served as method of reference. Sensitivity and specificity for detecting significant arterial stenoses with the used WB-MRA method was mod-erate to high for both contrast agents. Interobserver agreement for WB-MRA was good.

14:30         3893.     Blood Pool Enhanced MRA of Carotid Arteries: Added Value of Steady State Imaging.

Michele Anzidei1, Alessandro Napoli2, Beatrice Cavallo Marincola2, Fulvio Zaccagna2, Pier Luigi Di Paolo2, Daniel Geiger2, Chiara Zini2, Carlo Catalano2, Roberto Passariello2

1Scienze Radiologiche, Universita' di Roma "Sapienza", Rome, Italy, Italy; 2Radiological Sciences, Sapienza University of Rome, Rome, Italy, Italy

Carotid artery stenosis is a frequent cause of cerebrovascular ischemic events. Degeneration of plaque structure,surface irregularities and ulcerations are considered additional factors that must be taken

15:00         3894.     Whole-Body Imaging of Vascular Pathology in Fibulin-4 Mice Using Gd-Liposomes and Magnetic Resonance Angiography

Piotr Alfred Wielopolski1, Gerben Koning1, Paula van Heijningen1, Eric Kaijzel2, Clemens Lowik2, Monique Bernsen1, Jeroen Essers1

1Erasmus MC, Rotterdam, Zuid-Holland, Netherlands; 2Leiden University Medical Center, Netherlands

Fibulins are a six-member protein family hypothesized to function as intermolecular bridges that stabilize the organization of extracellular matrix structures as elastic fibers and basement membranes. Previously, we generated a mouse model underexpressing Fibulin-4 and showed that reduced expression of Fibulin-4 leads to aneurism formation, dissection of the aortic wall and cardiac abnormalities. Mice homozygous for the Fibulin-4 reduced expression allele (Fibulin-4R/R) show dilatation of the ascending aorta and a tortuous and stiffened aorta, resulting from disorganized elastic fiber networks. The non-invasive and multi-contrast capabilities of magnetic resonance imaging (MRI) can aid tremendously in understanding this pathology and the effects of therapy.

 


 
Non-Contrast MRA
Exhibit Hall 2-3                    Monday 14:00-16:00          Computer 51

14:00         3895.     Flow-Sensitized Dephasing Prepared SSFP: A New Noncontrast MRA Technique

Zhaoyang Fan1,2, John Sheehan1, Xiaoming Bi3, Rohan Dharmakumar1, Renate Jerecic3, James Carr1, Debiao Li1,2

1Radiology, Northwestern University, Chicago, IL, USA; 2Biomedical Engineering, Northwestern University, Evanston, IL, USA; 3Siemens Medical Solutions USA, Inc., Chicago, IL, USA

This work proposed a new noncontrast subtraction MRA technique based on flow-sensitized dephasing (FSD) prepared SSFP. Its Mechanism and technical consideration were presented, along with preliminary results on volunteers at 1.5T. The feasibility of this approach on multiple vascular territories was successfully demonstrated. Further systematic optimization of the parameters is warranted for various applications. The flexibility of adapting the FSD strength to individual flow conditions of the patient for different vascular territories and degrees of disease is a major advantage of this new approach. This technique has the potential to be used as a screening tool for whole-body vascular examination.

14:30         3896.     Non-Contrast Enhance MRA and Diffusion Weighted Imaging for a Non Invasive and Safe Morphological-Functional MR Study in Patients with Renal Insufficiency

Isabelle Parienty1, Francis Jouniaux1, C C Fauré1, D Maiza1, A Prot1, C Tavernier1, G Rostoker2, Faiza Admiraal-Behloul3

1Centre d'imagerie du bois de verrieres, Antony, France; 2Centre Hospitalier  Privé Claude Gallien, Paris, France; 3MRI, Toshiba Medical Systems Europe, Zoetermeer, Netherlands

Renal insufficiency is a serious healthcare problem. The Iodine renal toxicity and the link of Gadolinium to Nephrogenic Systemic Fibrosis makes conventional imaging of the severely malfunctioning kidneys not safe for the patient. Functional imaging in nephrology where anatomy and physiology are jointly considered, is a necessary diagnostic tool in patients with renal insufficiency in general and more particularly in patients with renal artery stenosis (RAS); in this last group it is important to assess ischemic injury of the renal parenchyma in order to predict the benefit of a revascularization procedure. Non contrast Enhanced MRA techniques such as Time-SLIP (Time-Spatial Labeling Inversion Pulse) can be used to explore safely the renal arteries and Diffusion-weighted imaging (DWI) could be integrated to the protocol for an “all-in-one” morphological–functional MR study to assess renal parenchyma function. The aim of this preliminary study was to explore the clinical value of a totally safe “all-in-one” MR protocol in patients with moderate to severe renal insufficiency and suspected RAS.

15:00         3897.     Non Contrast-Enhanced 3D MR Angiography of Renal Arteries Using a Novel Inversion Recovery Steady State Free Precession Technique: Our Initial Experience

Mayil Krishnam1, Sachin Malik1,2, Yutaka Natsuaki3, Swati Deshmane1, Derek Lohan1, James Paul Finn1, Stefan G. Ruehm1, Gerhard Laub3

1Department of Radiology, Ronald Reagan Medical Center, University of California at Los Angeles, Los Angeles, CA, USA; 2School of Medicine, Case Western Reserve University, Cleveland, OH, USA; 3Siemens Medical Solutions, UCLA, Los Angeles, CA, USA

Navigator gated cardiac triggered inversion recovery steady-state free-precession (IR-SSFP) magnetic resonance angiography (MRA) has been utilized to image the renal arteries without breath holding or intravenous contrast. Following further optimization, we have implemented this novel sequence on our 1.5T MR scanner to assess the renal arteries with a scan time of approximately 5 minutes. IR-SSFP had better visibility, less motion artifacts, and satisfactory stenosis detection compared to contrast-enhanced MRA. Our results demonstrate that IR-SSFP MRA of the renal arteries provides high image quality and sufficient signal-noise ratio and contrast-noise ratio for the diagnosis of renal artery stenosis.

15:30         3898.     Evaluation of the Renal Arteries: Comparison of Two Types of Non-Contrast MRA and Dynamic Contrast MRA

Takayuki Masui1, Motoyuki Katayama1, Kimihiko Sato1, Hiroki Ikuma1, Hidekazu Seo1, Megumi Ishii1, Mitsuharu Miyoshi2, Naoyuki Takei2, Masayoshi Sugimura1, Tetsuji Tsukamoto2, Akihiko Kutsuna1

1Radiology, Seirei Hamamatsu General Hospital, Hamamatsu, Shizuoka, Japan; 2Japan Applied Science Laboratory, GE Yokogawa Medical Systems Ltd., Hino, Tokyo, Japan

We used two types of non-contrast(NC)MRA; FIESTA with flow preparation pulse (Flow-Prep) based on bipolar velocity encoding and FIESTA using Inherent Enhancement (Inhance) inflow inversion recovery technique (Inflow IR) for evaluations of renal arteries in comparison with contrast MRA.

 
Exhibit Hall 2-3                    Tuesday 13:30-15:30          Computer 51

13:30         3899.     Inhance (Inflow Inversion Recovery) Non-Contrast Renal MRA: Comparison with 3D Gadolinium Enhanced MRA in Clinical Patients

James F. Glockner1, Naoki Takahashi1, Akira Kawashima1, David Woodrum1, David W. Stanley2, Naoyuki Takei3, Mitsuharu Miyoshi3, Sun Wei2

1Radiology, Mayo Clinic, Rochester, MN, USA; 2GE Healthcare, Waukesha, WI, USA; 3Japan ASL, GE Yokogawa Medical Systems, Hino, Japan

Non-contrast renal MRA using an inflow inversion recovery SSFP sequence (Inhance) was performed in additiona to 3D CE MRA in 24 patients referred for renal MRA. Inhance images were of good-excellent quality in nearly all cases, and demonstrated good agreement with CE MRA for detection of significant renal artery stenosis. Our results suggest that this technique may be effective in investigating suspected renovascular disease in patients who have contraindications to gadolinium-based contrast agents.

14:00         3900.     Nonenhanced Renal MRA Using Time-SLIP with 3D Balanced SSFP: Optimization of Coronal Acquisition

Junji Takahashi1, Sachiko Isono2, Mitsue Miyazaki2,3, Yoshinori Tsuji1, Yusuke Hamada1, Takashi Yoshida1, Hiroshi Suzuki1

1Radiology, Toranomon Hospital, Tokyo, Japan; 2MRI, Toshiba Medical Systems Corp., Otawara, Tochigi, Japan; 3MRI, Toshiba Medical Research Institute, Vernon Hills, IL, USA

Nonenhanced renal 3D MRA using time-spatial labeling inversion pulse (time-SLIP) has been optimized using the inflow effect axial acquisition. The axial time-SLIP acquisition allows superb image contrast between the renal arteries and the background; however, the coverage is due to scan time. For slower blood flow, prolong blood traveling time (BBTI) is required. To overcome the coverage problem and extending the BBTI time, we proposed the coronal time-SLIP acquisition using an STIR pulse to suppress the background and fat signals. The coronal time-SLIP acquisition permits wide coverage of the renal arteries with good contrast between the renal blood and background.

14:30         3901.     Flow Inversion-Prepared Non-Contrast Enhancement in the Steady State (FINESS): A Novel SSFP-Dixon Technique for Non-Contrast MR Angiography of the Renal Arteries

Manojkumar Saranathan1, Ersin Bayram2, Vijay Nimbargi3, Ramesh Venkatesan3, Naoyuki Takei4, Mitsuharu Miyoshi4, Wei Sun2, James Glockner5

1Applied Science Laboratory, GE Healthcare, Rochester, MN, USA; 2MR Engineering, GE Healthcare, Waukesha, WI, USA; 3GE Healthcare, Bangalore, India; 4MR Applied Science Laboratory, GE Yokagawa Medical Systems, Hino, Japan; 5Dept. of Radiology, Mayo Clinic, Rochester, MN, USA

Contrast-enhanced MR Angiography (CEMRA) is widely used for evaluation of vascular pathology. Recent concerns about nephrogenic systemic fibrosis (NSF) after administration of Gadolinium based contrast agents in patients with compromised renal function have spurred interest in non-contrast MRA methods. SSFP imaging has shown great promise due to its high SNR and short scan times. Robust fat suppression is challenging at high field strengths due to B0 and B1 inhomogeneities. Furthermore, fat saturation pulses perturb the steady state, causing artifacts. We report a novel non-contrast MRA technique that combines an inversion-prepared dual-echo 3D SSFP scan with a two-point Dixon fat-water reconstruction algorithm and demonstrate its potential for imaging the renal arteries.

15:00         3902.     Non-Contrast-Enhanced MR Portography Using Spin Labeling Technique: Comparison of Balanced SSFP and Half-Fourier FSE Sequence.

Hiroshi Sugimura1, Kenichiro Yamaguchi1, Ryuzo Ochiai1, Eiji Furukoji1, Tatefumi Sakae1, Shozo Tamura1, Toshiya Azuma1, Tokunori Kimura2, Yoko Tamaribuchi2, Tatsuya Ohkubo2, Yoshio Machida3

1Radiology, Miyazaki University, Miyazaki, Japan; 2Toshiba Medical Sysyems, Tokyo, Japan; 3Tohoku University Graduate School of Medicine, Sendai, Japan

The purpose of this study was to make a comparison between 3D balanced steady state free precession (SSFP) sequence and 3D half-Fourier FSE to explore the non-contrast-enhanced MR portography using spin labeling technique.To investigate intra-hepatic portal branches, the MR Portography using half-Fourier FSE technique provides better quality images than that with SSFP sequence. The 3D balanced SSFP sequence is suitable for the investigation of main portal trunk because of lower burring artifacts. The MR Portography using the time-SLIP technique serves as a useful tool for screening procedures of portal vein.

 
Exhibit Hall 2-3                    Wednesday 13:30-15:30          Computer 51

13:30         3903.     Noncontrast MRA of Distal Lower Extremities Using Flow-Sensitized Dephasing Prepared SSFP

Zhaoyang Fan1,2, John Sheehan1, Xiaoming Bi3, Timothy J. Carroll1,2, Renate Jerecic3, James Carr1, Debiao Li1,2

1Radiology, Northwestern University, Chicago, IL, USA; 2Biomedical Engineering, Northwestern University, Evanston, IL, USA; 3Siemens Medical Solutions USA, Inc., Chicago, IL, USA

The present work developed a new noncontrast subtraction MRA method in lower extremities based on flow-sensitized dephasing (FSD) prepared SSFP. Optimization of FSD gradient strength was performed for healthy volunteers at 1.5T to achieve the highest arterial SNR, artery-vein CNR. Promising results were also obtained from patient with peripheral artery disease. Further optimization of the parameters on patients is warranted. The flexibility of choice on the FSD gradient strength and direction allows adapting the technique to individual physiological conditions in patients to achieve optimal results. It is therefore anticipated that this technique could be applied to other vascular territories.

14:00         3904.     Highly Accelerated Non Contrast Enhanced MRA of the Lower Extremity Arteries at 3 Tesla Using an ECG-Triggered Variable Flip Angle 3D Fast Spin Echo (SPACE) Sequence

Ruth P. Lim1, Pippa Storey1, Iliyana P. Atanasova1, Danny C. Kim1, Elizabeth M. Hecht1, David R. Stoffel1, Jian Xu2, Qun Chen1, Henry Rusinek1, Vivian S. Lee1

1Radiology, NYU Langone Medical Center, New York, USA; 2Siemens Medical Solutions, New York, USA

The high SNR of ECG-triggered fast spin echo MRA at 3T may lend itself well to parallel imaging with potential benefits of allowing higher spatial resolution and/or shorter acquisition times. We implement an ECG-triggered variable flip angle 3D fast spin echo MRA technique and compare image quality and vessel conspicuity using parallel imaging in the phase encode direction alone versus parallel imaging in both slice select and phase encode directions. We find satisfactory image quality and vessel conspicuity can be maintained with substantially decreased imaging time.

14:30         3905.     Evaluation of the Femoral Arteries: Before or After Tumor Treatments Using Non-Contrast MRA Using Subtraction Method Based on Velocity Encoding Technique

Takayuki Masui1, Motoyuki Katayama1, Mitsuharu Miyoshi2, Kimihiko Sato1, Hiroki Ikuma1, Hidekazu Seo1, Masayoshi Sugimura1, Megumi Ishii1, Naoyuki Takei2, Tetsuji Tsukamoto2

1Radiology, Seirei Hamamatsu General Hospital, Hamamatsu, Shizuoka, Japan; 2Japan Applied Science Laboratory, GE Yokogawa Medical Systems Ltd, Hino, Tokyo, Japan

Flow Saturation Preparation (Flow-Sat-Prep) technique, which saturates flow signals in preparation pulse with velocity encoding and crusher gradients, is a non-contrast (NC) MRA technique for selective visualization of the artery and vein. In 20 patients, NC MRA demonstrated superficial femoral arteries and/or graft vessels without overlaps of the venous or background signals. NC MRA provided identical information to that of contrast enhanced (C) MRA regarding the patency of the femoral arteries and grafts. Without side effects related contrast agents, NC MRA might replace C MRA for the evaluation of the femoral arteries.

15:00         3906.     Nonenhanced MR Angiography of the Femoral Head Using Time-SLIP

Jun Isogai1, Mitsue Miyazaki2, Takeshi Shimada1, Hideo Hatakeyama1, Takashi Yamada1, Masashi Takeuchi1, Shizuaki Maejima1, Kenji Yodo3, Tomoko Miyata3

1Hasuda Hospital, Hasuda, Saitama, Japan; 2Toshiba Medical Research Institute USA, IL, USA; 3Toshiba Medical Systems Corporation, Saitama, Japan

Visualization of the proximal femur arteries is quite difficult using conventional nonenhanced MR angiography such as time-of-flight due to tortuous arterial trees and small vessels in the bone marrow. Gadolinium-enhanced MRA also has several problems with injection rates, the amount of contrast material, and the separation of arteries from veins. Due to the recent concerns of Gadolinium-related Nephrogenic Systemic Fibrosis (NSF), nonenhanced MRA solutions have gained interest. Visualization of small arteries of the proximal femur was investigated using time-spatial labeling inversion pulse (time-SLIP) with balanced steady-state free precession (bSSFP).

 
Exhibit Hall 2-3                    Thursday 13:30-15:30          Computer 51

13:30         3907.     Non-Enhanced MR Angiography of the External Carotid Artery and Its Branches Using True Steady-State Free-Precession (SSFP) Sequence with Time Spatial Labeling Inversion Pulse (T-SLIP) Technique

Naoe Satogami1, Tomohisa Okada1, Takashi Koyama1, Kimio Gotoh1, Toshikazu Kamae1, Kaori Togashi1

1Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan

Our purpose was to evaluate non-enhanced external carotid MR angiography using true SSFP with T-SLIP and to provide the optimal TI value. Images with TI of 600, 900, 1200, and 1500 ms were obtained in 20 volunteers and the main external carotid artery, eight first-order branches, and two second-order branches were visually scored. The relative signal intensity of the external carotid artery and sternocleidomastoid muscle was also calculated. True SSFP with T-SLIP showed favorable visibility of the external carotid artery system and a TI of 1200 ms was optimal from the perspective of arterial visualization and background suppression.

14:00         3908.     Steady State MR Angiography of the Carotid Arteries: Are Intravascular Agents Necessary? a Feasibility Study to Evaluate the Potential of Gadobenate Dimeglumine for Combined First Pass and High-Resolution Steady State Vascular Imaging

Alessandro Napoli1, Carlo Catalano, Michele Anzidei, Roberto Passariello

1Radiological Sciences, University Sapienza of Rome, Rome, Italy, Italy

High-resolution Steady-State (SS) imaging of arterial territories are successfully implemented as an adjunct to first-pass (FP) acquisition, thanks to the introduction of blood-pool agents (BPa); nevertheless, BPa are expensive and not widely available. For this reasons we tested the potential of gadobenate dimeglumine (MultiHance) for high resolution SS imaging as an addition to conventional FP CE-MRA for the detection of relevant stenosis of the carotid arteries. Our study demonstrates that the increased spatial resolution attainable on SS images combined with the elevated contrast enhancement of MultiHance permits improved detection of arterial stenoses, with diagnostic performance comparable to CTA and DSA.

14:30         3909.     Time-Efficient Artery and Vein Imaging in 3D TOF MRA of the Neck

Amir Eissa1, Alan H. Wilman1

1Dept. of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada

Imaging of arteries and veins with 3DTOF is generally a slow process owing to the need of two seperate scans. In this work we collect a full scan with no saturation pulses followed by a reduced extent scan with venous saturation. By combining both results, seperate artery and venous images are produced. This technique is studied in depth for imaging neck blood vessels.

15:00         3910.     3D Time-Of-Flight MR Angiography with 2D Partial Fourier Techniques and Sensitivity Encoding for Improved Acceleration

Yunhong Shu1, Clifton R. Haider1, John Huston1, Stephen Riederer1

1Radiology, Mayo Clinic, Rochester, MN, USA

Non-contrast 3D TOF MR angiography has been widely accepted as a clinic tool for evaluation of intracranial arteries. Multiple slabs are usually desired to cover a large field of view in the z direction, which induces long scan time. We hypothesize that it is feasible to combine 2D partial Fourier and sensitivity encoding with 3D TOF MRA providing reduced scan time and high diagnostic image quality. Phantom and volunteer experiments were performed to test the hypothesis.

 


 
Delayed Contrast Enhancement: Technique to Application
Exhibit Hall 2-3                    Monday 14:00-16:00          Computer 52

14:00         3911.     Three Dimensional Phase Sensitive Inversion Recovery (PSIR) Turbo FLASH for Evaluation of Left Ventricular Myocardial Lesions in Infiltrative and Non-Ischemic Cardiac Diseases

Aya Kino1, Sven Zuehlsdorff2, Aoife Keeling1, Cormac Farrelly1, John Sheehan1, Peter Weale2, Randal Ramsay1, Terry Cunningham1, Renate Jerecic2, James C. Carr1

1Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA; 2MR Research and Development, Siemens Medical Solutions, Chicago, IL, USA

 

14:30         3912.     1RR Phase Sensitive Inversion Recovery Late Gadolinium Enhancement MRI

Dana C. Peters1, Daniel A. Herzka2, Yuchi Han3, Reza Nezafat3, Basem Dokhan4, Warren J. Manning3

1Medicine, Cardiovascular Division, Beth Israel Deaconess Medical Center & Harvard Medical School, boston, ma, USA; 2Department of Biomedical Engineering, The Johns Hopkins University, Baltimore, MD, USA; 3Medicine, Cardiovascular Division, Beth Israel Deaconess Medical Center & Harvard Medical School, Boston, MA, USA; 4Institute of Biomedical Engineering, , Swiss Federal Institute of Technology (ETH Zürich), Zurich, Switzerland

We have developed a phase-sensitive inversion recovery (PSIR) late gadolinium enhancement (LGE) method using 1 RR (instead of 2) between inversions. This approach acquires a “back up” image in an acquisition window immediately following the first data acquisition. During this time, signal regrowth provides an image with a longer effective TI, which is useful if the first TI was too short. We preliminarily demonstrate the feasibility of this technique in patients. This technique has important applications for 3D LGE imaging, where 1RR LGE provides shorter scan times.

15:00         3913.     An Alternating Partial Fourier K-Space Segmentation Scheme for Imaging of Myocardial Delayed Enhancement

Dan W. Rettmann1, Manojkumar Saranathan1, Wei Sun2, James Glockner3

1Applied Science Laboratory, GE Healthcare, Rochester, MN, USA; 2MR Engineering, GE Healthcare, Milwaukee, WI, USA; 3Department of Radiology, Mayo Clinic, Rochester, MN, USA

An alternating partial Fourier segmented inversion recovery sequence is investigated as an optimal compromise between a conventional segmented and a single shot myocardial delayed enhancement imaging sequence. The technique is more robust to motion, has an inherit signal to noise improvement and an improved temporal resolution as compared to a single shot technique, yet maintains a relatively short scan time.

15:30         3914.     MADE: A Dark-Blood Delayed Enhancement Sequence to Improve Detection of Subendocardial Infarcts (Motion Attenuated Delayed Enhancement)

Michael Salerno1, Frederick H. Epstein2, Christopher M. Kramer1,2

1Department of Medicine, Cardiology, University of Virginia, Charlottesville, VA, USA; 2Department of Radiology, University of Virginia, Charlottesville, VA, USA

We have developed a motion-sensitized dark-blood delayed enhancement pulse sequence to improve detection of subendocardial myocardial infarcts.

 
Exhibit Hall 2-3                    Tuesday 13:30-15:30          Computer 52

13:30         3915.     Low Dose Gadobenate Dimeglumine in Delayed Enhancement Cardiac MRI

Larry Allen Kramer1, Roy Kumar, Sanjay Narotum, Catalin Loghin2, Eduardo J. Matta1, Anuradha T. Rao1, Khader M. Hasan1

1Radiology, UTHSC-Houston, Houston, TX, USA; 2Cardiology, UTHSC-Houston, Houston, TX, USA

Low dose gadobenate dimeglumine (0.1 and 0.05mg/kg) used in delayed-contrast enhancement cardiac MRI for myocardial viability was evaluated using early and late acquisition times following injection. 0.1 mg/kg showed efficacy in identifying myocardial infarctions after a minimum 10 minute time delay after injection. Initial results with 0.05 mg/kg also suggests potential efficacy in myocardial viability imaging after a minimum time delay of 10 minutes. Elevated Troponin T >1.0ng/mL trended towards improved identification of infarction before 10 minutes.

14:00         3916.     A Saturation-Recovery Inversion-Recovery “black-Blood” GRE Sequence for Detection of Delayed Enhancement in the Assessment of Myocardial Infarction at 3.0 Tesla – Preliminary Results

Kerstin Ulrike Bauner1, Andreas F. Biffar1, Martin Greif2, Alexander Becker2, Chistian Glaser1, Maximilian F. Reiser1, Armin M. Huber1

1Department of Clinical Radiology, University of Munich; Grosshadern hospitals, Munich, Germany; 2Department of Cardiology, University of Munich; Grosshadern hospitals, Munich, Germany

Small subendocardial infarctions are sometimes difficult to identify in late enhancement MRI, especially when the left ventricular cavity is bright. The aim of the study was therefore to image myocardial infarction with a multislice saturation recovery (SR) inversion recovery (IR) GRE sequence to null both, the signal of normal myocardium and blood in the ventricular cavity. A standard IR-GRE sequence in multislice technique served as reference technique. The calculation of contrast-to-noise ratios (CNR) resulted in no statistically significant differences regarding infarction/myocardium, however, CNR of infarction/left ventricular cavity was significantly higher in the SR-IR-GRE sequence. Image quality was equal.

14:30         3917.     Dark Blood Delayed Enhancement MRI for Evaluation of Myocardial Infarction and Non-Ischemic Cardiomyopathy in a Clinical Setting   

Cormac Farrelly1, Wolfgang Rehwald2, Aoife Keeling1, John Sheehan1, James Carr1

1Cardiovascular Imaging, Northwestern Memorial Hospital, Chicago, IL, USA; 2Siemens Medical Solutions, Chicago, IL, USA

Standard viability imaging are bright blood techniques and as such are limited in their evaluation of subendocardial areas of enhancement. This is because there is poor contrast between blood-pool and sub-endocardial foci of enhancement. Using a previously described dark blood technique that simultaneously nulls the blood-pool and myocardium 12 patients with subendocardial enhancement and clinical evidence of myocardial infarction and 10 patients with non-ischemic cardiomyopathy were evaluated.All patients demonstrated increased CNR between the hyper-enhancing myocardium and the blood pool on the dark blood technique compared to standard segmented TurboFLASH with acceptable preservation of CNR between hyper-enhancement and normal myocardium.This technique can be useful in a clinical setting for evaluation of infarction and non-ischemic cardiomyopathy.

15:00         3918.     Late Gadolinium Enhancement in Apparently Unenhanced Myocardium in Dilated Cardiomyopathy; Evaluation Using Myocardium to Lumen Ratio

Atsushi Kono1, Naoaki Yamada1, Teruo Noguchi2, Tadashi Watabe1, Yoko Masukata2, Yoshiro Hori1, Suzu Kanzaki1, Masahiro Higashi1, Hiroaki Naito1

1Department of Radiology and Nuclear Medicine, National Cardiovascular Center, Suita, Osaka, Japan; 2Division of Cardiology, National Cardiovascular Center, Suita, Osaka, Japan

We quantified myocardium-to-lumen signal ratio (M/L) to detect abnormality of apparently non-enhanced myocardium in dilated cardyomyopathy (DCM). We determined variability of normal M/L depending upon time after contrast injection and subject conditions such as heart rate and renal function, and evaluated M/L of DCM without apparent LGE. In the results, normal M/L was almost invariable in time between 2 to 20 minutes after gadolinium administration, and almost invariable depending upon subject conditions. M/L of DCM was significantly higher than M/L of normal myocardium. Higher M/L of DCM suggests increased interstitial tissue due to fibrosis and myocyte atrophy in DCM.

 
Exhibit Hall 2-3                    Wednesday 13:30-15:30          Computer 52

13:30         3919.     Phase-Sensitive Reconstruction to Improve Visualization of Ablation Scar in Left Atrium Wall

Eugene G. Kholmovski1, Sathya Vijayakumar1, Nassir F. Marrouche2

1UCAIR, Department of Radiology, University of Utah, Salt Lake City, UT, USA; 2Department of Cardiology, University of Utah, Salt Lake City, UT, USA

Pulmonary vein isolation using RF ablation is becoming a method of choice for treatment of atrium fibrillation. High-resolution, 3D delayed enhancement MRI (DE-MRI) can be used to detect post-ablation scarring. Visualization of the scar tissue in left atrium wall strongly depends on choice of inversion time for DE-MRI scan. Furthermore, lipid-rich anatomical structures adjacent to left atrium can be easily mistaken for scar tissue. Phase sensitive reconstruction using phase of aorta wall as reference is proposed to enhance contrast between scar tissue and the lipid-rich tissues and improve visualization of scar.

14:00         3920.     Early Enhancement with Gadobutrol Can Visualize Diffuse Myocardial Fibrosis in Dilated Cardiomyopathy : A Cardiovascular Magnetic Resonance Study

Oliver Strohm1, Myra Sabene Cocker1, Matthias G. Friedrich1

1Stephenson CMR Centre at the Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada

Dilated cardiomyopathy (DCM) is characterized by dilated ventricles and myocardial inflammation. Also present in DCM is diffuse, interstitial fibrosis. Current means of visualization of fibrosis is late gadolinium enhancement (LGE), but this requires the nulling of tissue to generate contrast between injured and healthy myocardium. However, in DCM there is the presence of diffuse fibrosis, which is also nulled for LGE. As such, LGE may not accurately assess diffuse fibrosis. However, early enhancement (EE) reflects early contrast uptake by myocardium, and has been found to be a surrogate marker of inflammation and hyperemia. Although, EE may also represent diffuse fibrosis. Thus, in this study, we sought to assess whether EE can assess diffuse fibrosis in patients with DCM.

14:30         3921.     hp-GRAPPA for Delayed Enhanced Imaging of the Left Atrium

Sathya Vijayakumar1, Nathan Burgon2, Feng Huang3, Eugene G. Kholmovski1, Edward DiBella1, Nassir F. Marrouche2

1UCAIR, Dept. of Radiology, University of Utah, Salt Lake City, UT, USA; 2Cardiology, University of Utah, Salt Lake City, UT, USA; 3Advanced Concept Development, Invivo Corporation, Gainesville, FL, USA

In this work, we present the application of high pass GRAPPA (hp-GRAPPA) to speed up high resolution delayed enhancement imaging of the left atrium. Preliminary results indicate that this image reconstruction technique can reduce acquisition time with minimal loss in image quality or diagnostic properties of the image.

15:00         3922.     Relationship Between Infarct Gray Zone and Characteristics of Ventricular Tachycardia Using Multi-Contrast Delayed Enhancement

Jay Stephen Detsky1,2, Gideon A. Paul3, Kim A. Connelly1,4, Alexander J. Dick3, Graham A. Wright1,2

1Imaging Research, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; 2Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; 3Schulich Heart Program, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; 4Cardiology, St. Michael's Hospital, Toronto, Ontario, Canada

In this study, the peri-infarct gray zone is determined using an automated analysis of multi-contrast delayed enhancement (MCDE) images in patients with ischemic cardiomyopathy. The size of the gray zone is shown to distinguish between patients who are and are not inducible for ventricular tachycardia (VT). The size of the gray zone is also shown to strongly correlate with the VT cycle length.

 
Exhibit Hall 2-3                    Thursday 13:30-15:30          Computer 52

13:30         3923.     Right Ventricular Involvement in Patients with Myocardial Infarction (MI): A Cardiac Magnetic Resonance (CMR) Study of Prevalence and Prognostic Implications

Iacopo Carbone1, Marco Francone2, Emanuela Algeri2, Federica Ciolina2, Ilaria Iacucci2, Federica Vasselli2, Carlo Catalano2, Roberto Passariello2

1La Sapienza University of Rome, Rome, Italy, Italy; 2La Sapienza University of Rome, Italy

Right ventricular (RV) involvement is frequent in patients (pts) with inferior myocardial infarction (MI) and its diagnosis is essential for appropriate patient management; however it is often misdiagnosed with conventional clinical-instrumental data. The aim of our study was to assess the role of late enhancement on CMR for detection of RV infarction and to evaluate its prevalence in a population of pts with acute and chronic MI. Our results showed that RV involvement is frequent in pts with an inferior MI (13/31), while ECG + echocardiography showed signs of RV involvement in 12/31 cases, with one case missed.

14:00         3924.     DE-MRI for Identifying the Ventricular Arrhythmia Substrate in Ischemic and Non-Ischemic Cardiomyopathy

Benoit Desjardins, MD-PhD1, Frank Bogun, MD2, Fred Morady, MD2

1Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; 2University of Michigan

The study seeks to determine whether DEMRI is a useful guide to mapping and ablation of ventricular arrhythmias in patients with ischemic and non-ischemic cardiomyopathy. DEMRI can indeed help identify the arrhythmogenic substrate and plan an appropriate mapping and ablation strategy.

14:30         3925.     Assessment of Pericardial Inflammation Using Delayed Enhanced Phase-Sensitive Inversion-Recovery TurboFLASH

Cormac Farrelly1, Aoife Keeling1, John Sheehan1, Edward Wu1, James Carr1

1Cardiovascular Imaging, Northwestern Memorial Hospital, Chicago, IL, USA

PSIR reconstruction of TurboFLASH imaging(PSIR-TFL)has been described for the evaluation of myocardial hyperenhancement after myocardial infarction.Theoretically it may also offer improved contrast between inflamed pericardium and adjacent myocardium or effusion. The purpose of this study was to compare phase images to magnitude images using PSIR-TFL in patients with pericarditis.22 male and 18 female patients with pericarditis were evaluated.The mean contrast difference between myocardium and enhanced pericardium was quantitatively and qualitatively better on PSIR compared to magnitude reconstruction. The contrast difference between pericardial fluid and pericardium was particularly large in all patients with pericardial effusions on PSIR due to a reversal in the amplitude of the fluid signal.Delayed enhanced PSIR reconstruction leads to improved contrast of inflamed enhanced pericardium with surrounding structures compared to magnitude reconstruction or standard post contrast T1 weighted imaging.

15:00         3926.     In Vivo Contrast Enhanced MRI for Quantification of Cardiac Function and Infarct Size After Stem Cell Therapies in Mice

Leonie Paulis1, Tessa Geelen1, Alexandra Klein2, Wilhelm Röll2, Bernd Fleischmann2, Klaas Nicolay1, Gustav Strijkers1
1Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands; 2Institute for Physiology I, Life and Brain Centre, University of Bonn, Bonn, Germany


The degenerative effects of myocardial infarction and LV remodeling can be partially counteracted by the use of stem cell therapies. In the current study, skeletal myoblasts and mesenchymal stem cells were transplanted in mice with myocardial infarction induced by either cryoinjury or permanent ligation of the left coronary artery. In vivo MRI performed at 14 days after transplantation demonstrated improved cardiac function, as deduced from CINE MRI, and a reduction in infarct size, as determined by the delayed enhancement of infarcted myocardium after intravenous injection of Gd-DTPA.

 


 
Cardiothoracic Imaging:  Form to Function
Exhibit Hall 2-3                    Monday 14:00-16:00          Computer 53

14:00         3927.     Magnetic Resonance Imaging Provides Non-Invasive Assessment of Pulmonary Hypertension Severity by Reduced Relative Area Change of the Pulmonary Artery

Alejandro Roldán-Alzate1, Scott B. Reeder1,2, Jon G. Keevil3, James R. Runo4, Christopher J. Francois2, Naomi C. Chesler1

1Biomedical Engineering, University of Wisconsin, Madison, WI, USA; 2Radiology, University of Wisconsin, Madison, WI, USA; 3Cardiology, University of Wisconsin, Madison, WI, USA; 4Medicine, University of Wisconsin, Madison, WI, USA

Pulmonary arterial hypertension (PAH) is a disease of the small distal pulmonary arteries characterized by an elevation in pulmonary arterial pressure. Currently, right heart catheterization is the only way to assess the severity of PAH. The relative cross sectional area change of the main pulmonary artery may be a useful non-invasive measure of PAH severity. Here, we use magnetic resonance imaging to measure the cross sectional area of the main pulmonary artery at different times during the cardiac cycle. Preliminary results on the utility of this metric are presented in five PAH patients and compared to four healthy controls

14:30         3928.     3D Contrast Enhanced MRA of the Pulmonary Arteries Using 2D Parallel Imaging (ARC); Rapid Single Breath Hold Pulmonary MRA in Patients with Dyspnea

Mark L. Schiebler1, Scott K. Nagle1, Scott B. Reeder1,2, christopher Francois1, Dana Tudorascu1,3, Reed F. Busse4, Anja Brau4, Jean H. Brittain4, Thomas Grist1

1Radiology, UW Madison, Madison, WI, USA; 2Medical Physics, UW Madison, Madison, WI, USA; 3Biostatistics, UW Madison, Madison, WI, USA; 4Applied Science Lab, General Electric, Waukesha, WI, USA

21 emergency room patients with dyspnea were studied with contrast enhanced 2D ARC 3D MRA of the pulmonary arteries. Three patients had a total of 5 emboli identified by this single breath hold MRA technique. In all cases the exam was diagnostic to the segmental level. This method can be safely used for young patients in whom radiation dose from CTA is problematic.

15:00         3929.     A Total Atherosclerotic Score for Whole Body MRA Is Related to Traditional Cardiovascular Risk Factors, IMT and Manifest Cardiovascular Disease

Tomas Hansen1, Håkan Ahlström2, Lars Lind3, Johan Wikström4, Lars Johansson2

1Dept of radiology, Uppsala, Sweden; 2Dept of radiology, Sweden; 3Dept of Medical sciences, Sweden; 4dept of radiology, Sweden

The aim of this study was to create a scoring system for whole body MRA that allows estimation of atherosclerotic induced luminal narrowing in a sample of 306 elderly subjects aged 70. The arterial tree was divided into 5 territories (carotid, aorta, renal, upper, lower leg) comprising 26 vessel segments, and assessed according to its degree of stenosis. The total atherosclerotic score (TAS) was significantly related to traditional cardiovascular (CV) risk factors included in Framingham risk score and IMT. The group with CV disease had a significantly higher mean TAS value (38.8) than the group without CV disease (23.3) (p=0.0006).

15:30         3930.     Quantification of Aortic Motion in Wild-Type and Apolipoprotein E-Deficient Mice Using Time Resolved MR Angiography: Possible Correlation Between Direction of Vessel Motion and Abdominal Aortic Aneurysm Bulging

Craig J. Goergen1, Maj Hedehus2, Charles A. Taylor1, Philip S. Tsao3, Joan M. Greve2

1Bioengineering, Stanford University, Stanford, CA, USA; 2Biomedical Imaging, Genentech Inc., South San Francisco, CA, USA; 3Cardiovascular Medicine, Stanford University, Stanford, CA, USA

The purpose of this study was to develop MR imaging methods to characterize aortic motion in mice. Using a 2D time-of-flight sequence, circumferential cyclic strain and direction of centroid motion were measured at four locations. The data presented suggests that aortic dynamics differ greatly above and below the renal arteries, with considerable leftward directionality of motion in the suprarenal region. These results are intriguing as this location is precisely where we observed leftward expansion in the angiotensin II/apolipoprotein E-deficient mouse abdominal aortic aneurysm model, suggesting a relationship between the direction of aortic motion and the shape of these aneurysms.

 
Exhibit Hall 2-3                    Tuesday 13:30-15:30          Computer 53

13:30         3931.     Free-Breathing Whole-Heart 3D Cardiac MRI at 3.0 Tesla for Characterization of Interatrial Septum: A Comparison with Multislice Computed Tomography

Abdalla A. Elagha1, Roderic I. Pettigrew1, Ahmed M. Gharib1

1NIH, Bethesda, MD, USA

Assessment of the interatrial septum has become an important requirement for the diagnosis of variety of l diseases, and for preplanning of a variety of interventional procedures demands precise characterization of the septum. Multi-detector CT has been shown as a valuable tool for the assessment of the IAS morphology, however, requires the use of radiation and potentially nephrotoxic contrast agents. The purpose of this study is to demonstrate the feasibly of using a free breathing 3 dimensional technique at 3T and to compare the IAS measurements from this method to CT. Linear regression analysis demonstrates the close relationship between measurements obtained using MRI and MSCT. Whole heart 3D MRI using free-breathing technique with contrast was feasible in all subjects, and allow for clear assessment of the IAS morphology and measurements, that was not significantly different from high resolution CT imaging, and without exposure to radiation hazards.

14:00         3932.     Improved MRI Assessment of the Left Atrial Appendage Using Delayed Enhancement Imaging  as Compared to Black Blood Fast Spin Echo Imaging

Thanh D. Nguyen1, Matthew D. Cham1, Jason Chinitz2, Pascal Spincemaille1, James K. Min1,2, Bruce B. Lerman2, Martin R. Prince1, Yi Wang1, Jonathan W. Weinsaft1,2

1Radiology, Weill Cornell Medical College, New York, NY, USA; 2Medicine/Greenberg Cardiology Division, Weill Cornell Medical College, New York, NY, USA

Left atrial appendage (LAA) imaging is important as this is a primary site for cardiac thrombus which causes embolic events. Delayed enhancement MRI (DE-MRI) has recently been shown to accurately evaluate left ventricular thrombus, but its utility for LAA imaging is not known. In this study, LAA imaging by DE-MRI and black blood fast spin echo (BB-FSE) were compared to a reference of cine SSFP. Single shot and segmented DE-MRI were found to provide similar measurements of LAA size and image contrast compared to SSFP. BB-FSE imaging suffers from severe intraluminal signal artifacts, leading to inaccurate measurements.

14:30         3933.     Coronary Veins Imaging Using Free-Breathing Whole-Heart 3D Cardiac Magnetic Resonance Imaging (MRI) at 3.0 Tesla: A Comparative Study with Multi-Detector Computed Tomography (MDCT)

Abdalla A. Elagha1, Roderic I. Pettigrew1, Ahmed M. Gharib1

1NIH, Bethesda, MD, USA

Recent studies show the feasibility of MDCT for assessment of coronary veins; however, it exposes patients to risk of use of ionizing radiation and potentially-nephrotoxic iodinated contrast agent. Alternatively, cardiac MRI at 3T has become a powerful tool for non-invasive evaluation of cardiovascular structures especially coronary arteries, with a potential ability to depict coronary veins since they are closely related and enhance with contrast administration. The purpose of this study is to evaluate the feasibility of 3T MRI to assess anatomy of coronary veins, and compare MRI measurements with those of MDCT. Regression analysis demonstrates close relationship between measurements of veins obtained by MRI and MDCT.Free-breathing whole-heart 3D technique at high field MRI (3T) is a feasible technique, providing high spatial resolution images and homogenous myocardial suppression. This allows for clear assessment and measurement of coronary veins, with comparable results with high resolution MDCT imaging, but with better safety profile.

15:00         3934.     Quantification of Pulmonary Vein Off-Resonance Frequency Through the Cardiac Cycle: Implications for Non-Contrast Pulmonary Vein MRA

Peng Hu1, Christian Stoeck1, Dana C. Peters1, Kraig V. Kissinger1, Beth Goddu1, Lois Goepfert1, Neil M. Rofsky1, Warren J. Manning1, Reza Nezafat1

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

Significant off-resonance exists in the pulmonary veins (PV) due to their close proximity to the lungs. In this study, we report that PV blood exhibits a mean off-resonance of 58~113Hz which remains relatively constant through the cardiac cycle. We use this frequency shift to enhance the PV blood signal in SSFP imaging.

 
Exhibit Hall 2-3                    Wednesday 13:30-15:30          Computer 53

13:30         3935.     Feasibility of Acoustically Triggered CINE Imaging for Global Cardiac Function Assessment Using an MR-Stethoscope

Tobias Frauenrath1,2, Fabian Hezel3,4, Jane F. Utting3, Gabriele A. Krombach3, Thoralf Niendorf3,5

1Department of Radiology, University Hospital,, RWTH Aachen, Germany; 2Department of Phoniatrics, Pedaudiology and Communication Disorders, University Hospital,, RWTH Aachen, Germany; 3Department of Radiology, University Hospital, RWTH Aachen, Germany; 4Institute for Signal Processing, University of Luebeck, Germany; 5Faculty of Mathematics, Computer Science and Natural Science, RWTH Aachen, Germany

As high-field cardiac MRI becomes more widespread the propensity of ECG recordings to interference from electromagnetic fields increases and with it the motivation for a practical gating/triggering alternative. This study explores the feasibility, efficacy and reliability of acoustic cardiac triggering (ACT) for 2D CINE SSFP imaging at 1.5 T and 3.0 T including left ventricular function and endocardial border sharpness assessment. The MR stethoscopes intrinsic insensitivity to interference with electro-magnetic fields and hydro-dynamic effects renders it suitable for assessment of global cardiac function due to its excellent trigger reliability – even at high magnetic field strengths.

14:00         3936.     Adaptive Heart Rate Prediction for Black-Blood Systolic Imaging

Julien Oster1,2, Brice Fernandez1,3, Maélène Lohezic1,3, Damien Mandry1,4, Pierre-André Vuissoz1,2, Olivier Pietquin1,5, Jacques Felblinger1,2

1U947, Inserm, Nancy, France; 2IADI, Nancy-Université, Nancy, France; 3Global Applied Science Lab., GE Healthcare, Nancy, France; 4CHU de Nancy, Nancy, France; 5IMS Research Group, SUPELEC Metz Campus, Metz, France

Cardiac MRI is still challenging. Image acquisitions are generally synchronized on R-waves of the electrocardiogram in order to avoid cardiac motion artifacts. Double inversion recovery fast spin echo sequences, which result in black-blood images, require an inversion time to cancel blood signal. This specific timing makes black-blood systolic imaging impossible. An adaptive heart rate prediction method, which combines a simple heart rate modeling and Kalman filtering, is described. Its implementation in a real-time hardware enables triggered acquisitions in every desired cardiac phase, without preparation time constraint. Black blood systolic images are presented demonstrating the acquisition strategy accuracy.

14:30         3937.     Free-Breathing Real Time Cardiac Function Assessment in Patients: A 3T Versus 1.5T Study

Jean-Noel Hyacinthe1, Magalie Vialon2, Alexandru Cernicanu2, Chirine Parsei2, Sven Zuehlsdorff3, Pierre Croisille4, Pierre-Frederic Keller2, Dominique Didier2, Jean-Paul Vallee5,6

1University of Geneva, Switzerland; 2Geneva University Hospital; 3Siemens Medical Solutions USA; 4University of Lyon (Fr); 5Radiology, University of Geneva, Geneva, Switzerland; 6Work supported in part by the Center for Biomedical Imaging (CIBM), Geneva,, Lausanne, Switzerland

This study evaluated the benefit of free breathing real time imaging of the cardiac function at 3T by comparison to 1.5T in 13 volunteers and 26 patients. Gain in myocardial SNR but not myocardial/blood CNR was observed at 3T by comparison to 1.5T. Accurate determination of the diastole, systole and EF was obtained with the real-time sequences. For regional function determination, sensitivity and specificity of the real time sequence at 3T was 80% and 98%. Therefore, free breathing real-time cardiac MRI is a valuable alternative for difficult patients.

15:00         3938.     Cardiac Cine: Advances at 7T

Lance J. DelaBarre1, peter weale2, Carl j. Snyder1, Pierre-Francois van de Moortele1, Greg Metzger1, Sven Zuehlsdorff2, Sonia Nielles-Vallespin3, Pat Bolan1, Eddie J. Auerbach1, Kamil Ugurbil1, Renate Jerecic2, John Thomas Vaughan1

1CMRR - Radiology, U of Minnesota, Minneapolis, MN, USA; 2Siemens Medical Solutions, Chicago, IL, USA; 3Siemens Healthcare, Erlangan, Germany

Cardiac imaging at 7T offers improvements in SNR and coil geometry factors, both of which can be exploited to by T-GRAPPA techniques to improve temporal-spatial resolution in cardiac cines. B1 shimming with independently driven sixteen-channel transceive arrays improves the homogeneity over the heart and provides excellent coil geometry for parallel imaging for T-GRAAPA acceleration at 7T. T-PAT accelerated tagged cines and real-time, free-breathing T-PAT accelerated gradient echo cines acquired at 7T are presented.

 
Exhibit Hall 2-3                    Thursday 13:30-15:30          Computer 53

13:30         3939.     Whole Heart Flow Sensitive 4D MRI

Alex Frydrychowicz1, Philipp Blanke1, Max Russe1, Jelena Bock1, Aurelien F. Stalder1, Daniela Föll2, Raoul Arnold3, Philip Kilner4, Michael Markl1

1Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany; 2Cardiology, University Hospital Freiburg, Freiburg, Germany; 3Pediatric Cardiology, University Hospital Freiburg, Freiburg, Germany; 4Royal Brompton Hospital, Imperial College, London, UK

The aim of this study was to demonstrate the feasibility of time-resolved 3-directional flow-sensitive 3-dimensional MRI (flow sensitive 4D MRI) to provide a comprehensive overview of principal blood movements through both sides of the human heart and great vessels. 3D visualization of flow connectivity and application to congenital heart disease underline the potential of whole heart approach for the evaluation of normal and altered complex flow.

14:00         3940.     Turbulence Mapping Extends the Utility of Phase-Contrast MRI in Mitral Valve Regurgitation

Petter Dyverfeldt1, John-Peder E. Kvitting1, Gabriella Boano2, Carljohan Carlhäll1, Andreas Sigfridsson1, Ulf Hermansson2, Ann F. Bolger3, Jan Engvall1, Tino Ebbers1

1Linköping University and Center for Medical Image Science and Visualization (CMIV), Linköping, Sweden; 2Linköping University Hospital, Linköping, Sweden; 3University of California San Francisco, San Francisco, CA, USA

The blood flow associated with mitral valve insufficiency is difficult to assess using current clinical MRI methods. In this study, MRI turbulence measurements were applied in five patients with severe mitral valve regurgitation. In all the patients, elevated turbulence intensity was found in the atrium along the course of the regurgitation jet. The results suggest that MRI is consistently able to provide measurements of turbulence intensity in patients with this clinically important valve lesion. This may open up for novel perspectives on risk stratification of patients with valve disease and could be useful in the evaluation of different treatment strategies.

14:30         3941.     Optimized Estimation of Global and Regional Aortic Pulse Wave Velocity

Michael Markl1, Wolf Wallis2, Stefanie Brendecke2, Jan Simon2, Alex Frydrychowicz1, Cornelius Weiller2, Jürgen Hennig1, Andreas Harloff2

1Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany; 2Neurology, University Hospital Freiburg, Freiburg, Germany

The aim of this study was to evaluate the value of time-resolved 3-directional 3-dimensional Phase Contrast MRI (flow sensitive 4D MRI) for the assessment of pulse wave velocity in the thoracic aorta for normal (12 healthy volunteers) and pathological (9 patients with aortic atherosclerosis) vascular compliance. Results from pulse wave velocity calculations incorporated velocity data from the entire aorta and were compared to standard methods based on flow waveforms at specific anatomical landmarks. Additionally, the volumetric coverage of flow-sensitive 4D MRI permitted the analysis of normal and altered regional PWV in the ascending aorta, aortic arch, and descending aorta.

15:00         3942.     In-Vitro Turbulence Mapping in Prosthetic Heart Valves Using Generalized Phase-Contrast MRI

Petter Dyverfeldt1, John-Peder E. Kvitting1, Andreas Sigfridsson1, Stefan Franzén2, Ann F. Bolger3, Tino Ebbers1

1Linköping University and Center for Medical Image Science and Visualization (CMIV), Linköping, Sweden; 2Linköping University Hospital, Linköping, Sweden; 3University of California San Francisco, San Francisco, CA, USA

Turbulent flow is a sign of suboptimal hemodynamics in prosthetic heart valves. In this in-vitro study, MRI turbulence measurements were made in four common designs of prosthetic heart valves. Elevated values of turbulence intensity were detected downstream from all the studied valves. Distinct differences in the extent and degree of turbulence intensity were observed between the different valves. Non-invasive MRI turbulence measurements add a new dimension to the hemodynamic evaluation of current and future prosthetic heart valves.

 


 
Muscle & Bone
Exhibit Hall 2-3                    Monday 14:00-16:00          Computer 54

14:00         3943.     Diffusion Weighted Imaging of Bone Marrow : Comparison of Apparent Diffusion Coefficients of Normal Bone Marrow and Metastatic Bone Disease to Inform the Development of a Protocol Optimised to Metastatic Bone Disease

Christina Messiou1, Veronica A. Morgan1, David J. Collins1, Nandita M. deSouza1

1Cancer Research UK Clinical Magnetic Resonance Research Group, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Sutton, Surrey, UK

The role of diffusion weighted (DW) MRI in imaging of soft tissue tumours had evolved rapidly. However its application to bone disease has not yet been fully exploited because the unique microarchitecture of normal and pathological bone marrow present challenges. The aim of this study was to identify the apparent diffusion coefficient (ADC) of normal bone marrow and bone metastases in order to develop a DW MRI protocol optimised to bone. Bone marrow is significantly restricted compared to marrow pathology of various types. Optimised contrast can be obtained using higher b values-We suggest a maximum b value of 1400 smm-2.

14:30         3944.     Bone Segmentation Algorithm by Using Geometric Features in Magnetic Resonance Imaging

June-Goo Lee1,2, Youngkyu Song3, Jee-Hyun Cho3, Jong Baek Seo3, Jong Hyo Kim2, Gyunggoo Cho3

1Division of Proteome Research/Bio-Magnetic Resonance Research Center, Korea Basic Science Institute, Cheongwon, Chungbuk, Korea; 2Interdisciplinary Program in Radiation Applied Life Science, Seoul National University College of Medicine; 3Division of Proteome Research/Bio-Magnetic Resonance Research Center, Korea Basic Science Institute, Cheongwon, Chungbuk , Korea

This study is designed to overcome partial volume effect which is inevitably appeared in the low resolution MR trabecular bone images.

15:00         3945.     Solid-State 1H and 31P MRI Detects Changes in Bone Mineralization and Water Content in OVX Rat Bone in Response to Treatment with Alendronate

Sailaja Anumula1, Debra Horng1, Suzanne L. Wehrli2, Jeremy Magland1, Felix W. Wehrli1

1Department of Radiology, Laboratory for Structural NMR Imaging, University of Pennsylvania School of Medicine, Philadelphia, PA, USA; 2NMR Core Facility, The Childrens Hospital of Philadelphia, Philadelphia, PA, USA

We hypothesize that hormone loss following menopause results in decreased degree of mineralization of bone (DMB) and increased water content. The antiresorptive agent alendronate (ALN) is known to increase DMB to a level similar to that in premenopausal women. We test the above hypothesis by quantifying bone mineral phosphorus and water content by 3D radial 31P and 1H imaging in ovariectomized rats in response to treatment with ALN. The results support our hypothesis and are in agreement with other means of mineral and water quantification.

15:30         3946.     Comparative Analysis of Capability for Bone Metastases Assessment Among Whole-Body Diffusion-Weighted Imaging, Whole-Body MR Imaging Without and with Diffusion-Weighted Imaging, Bone Scan and Whole-Body FDG-PET/CT in Non-Small Cell Lung Cancer Patients

Keiko Matsumoto1, Yoshiharu Ohno1, Hisanobu Koyama1, Munenobu Nogami2, Daisuke Takenaka1, Yumiko Onishi1, Nobukazu Aoyama3, Hideaki Kawamitsu3, Kazuro Sugimura1

1Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan; 2Division of Image-Based Medicine, Institute of Biomedical Research and Innovation, Kobe, Hyogo, Japan; 3Division of Radiology, Kobe University Hospital, Kobe, Hyogo, Japan

Accurate tumor staging is essential for choosing the appropriate treatment strategy in non-small cell lung cancer (NSCLC) patients. Recently, whole-body MRI without and with diffusion-weighted image (DWI) has been suggested as useful for assessment of distant metastases in oncology patients. However, no direct comparison of diagnostic accuracy for bone metastasis assessment has been made among whole-body MR imaging without and with DWI, bone scan and FDG-PET/CT in NSCLC patients. The purpose of this study was to prospectively and directly compare the capability for bone metastasis assessment whole-body MR imaging with and without DWI, integrated FDG-PET/CT and bone scan.

 
Exhibit Hall 2-3                    Tuesday 13:30-15:30          Computer 54

13:30         3947.     Internal Gradient Evaluation in Spongy Bone as a Potential NMR Parameter to Detect Osteoporosis Disease

Silvia De Santis1,2, Mauro Rebuzzi2, Giulia Di Pietro1, Bruno Maraviglia3,4, Silvia Capuani2

1Physics Department Sapienza University Rome, Rome, Italy; 2CNR-INFM SOFT, Physics Department Sapienza University Rome, Rome, Italy; 3MARBIlab Enrico Fermi Center, Rome, Italy; 4Santa Lucia Foundation, Rome, Italy

In porous systems such spongy-bone, characterized by strongly magnetic-susceptibility differences between trabecular-bone and bone-marrow, internal gradient Gi can be extracted from the SE decay. Aims of this work were: 1) to evaluate the Gi of the spongy-bone in-vitro, in order to relate this quantity with trabecular-bone properties; 2) to assess, in-vivo, the potential ability of Gi to evaluate the spongy-bone status when applied to human calcanei. Our results indicate Gi as a potential diagnostic marker of osteoporosis. In fact the in-vitro and in-vivo results demonstrate that Gi values depend on both solid trabecular bone characteristics and liquid interstitial bone-marrow quality.

14:00         3948.     High-Resolution 3D UTE Imaging of Cortical Bone

Ahi Sema Issever1,2, Peder Larson1, Sharmila Majumdar1, Dan Vigneron1, Roland Krug1, Wang Chunsheng1, Thomas Link1

1UCSF, San Francisco, CA, USA; 2Charité, Berlin, Germany

UTE MR imaging promises to be a powerful alternative to quantify bone quality in cortical bone aside from its density. It may thus be considered a potential new tool in the assessment of fracture risk or in the monitoring of osteoporosis therapy. In this study we introduce a high-resolution 3D UTE MR sequence that is capable of depicting cortical bone at an isotropic voxel size below 500 μm allowing instant image reformation.

14:30         3949.     In Vivo Measurement of Cortical Bone Bulk Susceptibility with Ultrashort TE (UTE) Pulse Sequences

Jing-Tzyh Alan Chiang1, Jiang Du1, Atsushi Takahashi2, Robert F. Mattrey1, Graeme Bydder1

1Radiology, University of California San Diego, San Diego, CA, USA; 2Applied Science Laboratory, GE Health Care

Direct MR imaging of cortical bone can be accomplished by ultrashort TE (UTE) pulse sequences that overcome cortical bone’s extremely short T2. The bulk susceptibility of bone is a parameter of biological interest, and previously it has been measured in vitro in powder form and indirectly in vivo. We present here a simple, direct approach for in vivo measurement of cortical bone bulk susceptibility using phase differences obtained by UTE imaging at two different submillisecond TEs.

15:00         3950.     Quantitative Imaging of Cortical Bone Using Ultrashort TE (UTE) Sequences

Jiang Du1, Won Bae1, Michael Carl2, Mark Bydder1, Atsushi M. Takahashi2, Reni Biswas1, Christine B. Chung1, Graeme M. Bydder1

1Radiology, University of California-San Diego, San Diego, CA, USA; 2Global Applied Science Laboratory, GE Healthcare Technologies, Menlo Park, CA, USA

Mineralized bone tissue has a significant water component of approximately 15-20% by volume. Quantification of bone water may be able to capture changes in porosity during aging and progression of osteoporosis, and provide a means of assessing response to treatment. However, bone appears as a signal void with all types of clinical MR sequences. Ultrashort TE (UTE) sequences with TEs down to 100 ƒÝs or shorter permit direct imaging and quantification of bone. In this study we report a fast and efficient 2D UTE technique to quantify T1, T2* and bone water using a clinical 3T scanner.

 
Exhibit Hall 2-3                    Wednesday 13:30-15:30          Computer 54

13:30         3951.     Muscle Intracellular Free [Mg2+] Assessed by 31P MRS in Patients with Chronic Intestinal Failure  on Long-Term Home Parenteral Nutrition

Loris Pironi1, Emil Malucelli2, Maria Cristina Guidetti1, Giovanna Farruggia3, Bruno Barbiroli2, Stefano Iotti2

1Dipartimento di Medicina Interna e Gastroenterologia, University of Bologna, Italy; 2Dipartimento di Medicina Interna dell’Invecchiamento e delle Malattie Nefrologiche, University of Bologna, Bologna, Italy; 3Dipartimento di Biochimica, University of Bologna, Italy

Low serum concentrations of Mg and K have been reported in 2-30% of patients receiving long-term Home-Parenteral-Nutrition (HPN). We assessed by 31P-MRS the [Mg2+] in the calf muscle of 21 patients with Chronic-Intestinal-Failure receiving HPN. Muscle [Mg2+ ] was normal in all patients despite 30% of them had low serum [Mg]. Skeletal muscles Mg content showed to be more consistent with the patients electrolytic status than that of serum [Mg]. We also found correlations of opposite sign of muscle [Mg2+] and serum [Mg] versus serum [PTH] showing the different functional meaning of the Mg present in the two compartments.

14:00         3952.     BOLD Response of Different Muscles to Ischemic Exercise

Albrecht I. Schmid1,2, Martin Andreas2, Martin Meyerspeer1, Ewald Moser1, Michael Wolzt2

1MR Center of Excellence, Medical Univeristy of Vienna, Vienna, Austria; 2Dept. of Clin. Pharmacology, Medical Univeristy of Vienna, Vienna, Austria

Limited tissue perfusion and ischemia are frequent complications in various disorders. We investigated echo planar imaging (EPI) bold signal during cuff-ischemia (20 min). Five healthy, male volunteers were studied in a Siemens 3T scanner. During the last 110±50s the subjects performed planar flexion which is mainly performed by the gastrocnemius muscle. The reactions of three different muscles, gastrocnemius, soleus and tibialis anterior, were analysed. Soleus muscle had a lower signal during ischemia, gastrocnemius had a longer and flatter response during post-ischemic hyperemia.

14:30         3953.     B0 and B1 Correction of High Field T2 Maps of Human Calf Muscle

E. Brian Welch1, Mark D. Does2, Robin Avison2, J. Christopher Gatenby2, Malcolm J. Avison2, Bruce M. Damon2, John C. Gore2

1MR Clinical Science, Philips Healthcare, Cleveland, OH, USA; 2Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA

Rigorous T2 mapping of human calf muscle at high field (3T) using a multi-slice, multi-echo turbo spin echo sequence is possible, but attention must be paid to refocusing slice properties (profile shape and thickness) and to the crushing scheme employed to eliminate stimulated echoes. At high static field, B0 and B1 inhomogeneities also strongly affect T2 estimates, but such effects can be corrected. After these steps, image-based T2 maps should agree with results obtained from other non-image-based T2 measurements such as single voxel selective spectroscopy. This work demonstrates these effects and corrections on phantoms and in vivo.

15:00         3954.     Diffusion Tensor Derived Soleus Architecture at Rest and Under Plantarflexion.

Usha Sinha1, John Hodgson2, Shantanu Sinha2

1Physics, San Diego State University, San Diego, USA, USA; 2Radiology, University of California at San Diego, San Diego, CA, USA

The soleus muscle of the calf has a complex architecture with implications for its function. We have used diffusion tensor imaging to map and visualize the muscle fibers as the orientation of the leading eigenvector. DTI helps vSynopsis anterior and posterior compartments including the bipennate arrangement in the anterior soleus; and possibly the marginal soleus as well. There was qualitative agreement with DTI derived fiber directions to that reported from a 3D model and from the Visible Human data. Large changes in fiber direction in the anterior compartment were seen with plantarflexion.

 
Exhibit Hall 2-3                    Thursday 13:30-15:30          Computer 54

13:30         3955.     Preliminary Study for the Evaluation of the Muscle-Derived Stem Cell Metabolism Using MR Spectroscopy

Song I. Chun1, Tae Hyung Kim1, Kee Chin Tan1, Min Young Choi2, Jee Hyun Cho3, Kwan Soo Hong3, Jung Woog Shin1, Ok Chan Jung1, Young Il Yang4, Chi Woong Mun1

1Dept. of Biomedical Engineering, Inje University, Gimhae, Korea; 2Paik Institute of Clinical Reserch, Inje University, Busan, Korea; 3Korea Basic Science Institute, Ochang, Korea; 4Dept.of Pathology, Paik Hospital, Inje University, Busan, Korea

The purpose of this study is to observe cell metabolism with MRS when a MDSCs is differentiated into fat. Three experimental groups used MDSCs that cultured in 3 dimensional system, Group1(fibrin gel), Group2(fibrin+undifferentiated MDSCs: cultured 1day, 1week), Group3(fibrin+ differentiated MDSCs: cultured 1week). The spectrum from each group has been acquired by utilizing vertical-bore 14.1T NMR/MRI with PRESS pulse sequence. Compare to spectrums of group 1, 2 and 3, we analyzed metabolite peaks newly formed during the differentiation of the MDSCs. In the result, the common peaks at 3.7/3.5/1.8/1.22/0.8ppm have been detected at each spectrum. Group 3, cultured MDSCs for 1 week into fat, came out a new peak at 2.6ppm and the increase of lipid peaks were also shown. In this study, therefore, we could observe the metabolite change along with MDSCs differentiation and found the potential possibilities of MRS to evaluate the differentiations of stem cell.

14:00         3956.     Gender-Specific Differences in MR Fiber Tractography of Skeletal Muscles

Yoshikazu Okamoto1, Akira Kunimatsu2, Tatsuo Kono3, Yuka Kujiraoka4, Manabu Minami1

1Radiology, Tsukuba University Hospital, Tsukuba, Ibaraki, Japan; 2Radiology, Tokyo University Hospital, Tokyo, Japan; 3Radiology, Ibaraki Children's Hospital, Mito, Ibaraki, Japan; 4Radiology, Tsukuba Memorial Hospital, Tsukuba, Ibaraki, Japan

The purpose of this study is to elucidate gender diffeerence on MR fibertractography of skeletal muscle.

14:30         3957.     Muscle Functional Magnetic Resonance Imaging of the Trunk

Noriyuki Tawara1, Osamu Nitta2, Hironobu Kuruma2, Mamoru Niitsu3, Atsuto Hoshikawa1, Toru Okuwaki1, Akiyoshi Itoh4

1Department of Sports Medicine, Japan Institute of Sports Sciences, Tokyo, Japan; 2Department of Physical Therapy, Tokyo Metropolitan University, Tokyo, Japan; 3Department of Radiological Sciences, Tokyo Metropolitan University, Tokyo, Japan; 4NIHON University, Chiba, Japan

Exercise induced Muscle activity is essential in sports medicine and rehabilitation medicine, especially the trunk muscle. Magnetic resonance imaging (MRI) can evaluate activity of the muscle; transverse relaxation time (T2) of exercised muscle increases compared to that of the rest muscle. The previous studies proposed the muscle functional magnetic resonance imaging (mfMRI) which visualized muscle activity with enhanced activated muscle. However, for calculating T2, the mfMRI using the spin echo (SE) sequence requires minutes of the acquisition time. And the body parts of the mfMRI were limited to the limbs. We proposed and verified the feasibility of mfMRI using ultrafast imaging (fast-acquired mfMRI: fast-mfMRI). The purpose of this study is to evaluate the trunk muscle activity using fast-mfMRI.In this study, we presented the fast-mfMRI demonstrating the functional information with detailed morphologies. One of the advantages of the fast-mfMRI is rapid scan time advantageous for the human trunk imaging.

15:00         3958.     Correlation Between Muscle Magnetization Transfer Ratio and Muscle Strength in Chronic Inflammatory Demyelinating Ployneuropathy

Christopher David James Sinclair1,2, Mario A. Miranda1,2, Pedro Cowley2, Mary Reilly1, John S. Thornton1,2, Tarek A. Yousry1,2

1Institute of Neurology, University College London, London, UK; 2Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, London, UK

Magnetization transfer ratio (MTR) maps of the lower legs of nine adult patients suffering from chronic inflammatory demyelinating polyneuropathy (CIDP) and ten healthy control subjects were obtained. Clinical severity in the CIDP patients was assessed by manual muscle strength testing of ankle dorsiflexion. The median MTR across all lower leg muscles for the CDIP group was significantly lower than for the controls. MTR in the anterior compartment of the leg correlated significantly with reduced clinical muscle strength. MTR may provide a valuable surrogate biomarker of disease severity in future therapeutic trials in CIDP and other neuromuscular conditions.

 


 
Cartilage:  Technical Modifications & Repair
Exhibit Hall 2-3                    Monday 14:00-16:00          Computer 55

14:00         3959.     Improved Fat Suppression Using Multi-Peak Reconstruction for IDEAL Chemical Shift Fat-Water Separation: Application with Fast Spin Echo Imaging

Richard Kijowski1, Michael Woods1, Kenneth Lee1, Kuya Takami1, Huanzhou Yu2, Ann Shimakawa2, Jean Brittain3, Scott Reeder1,4

1Radiology, University of Wisconsin, Madison, WI, USA; 2Applied Science Laboratory, GE Healthcare, Menlo Park, CA, USA; 3Applied Science Laboratory, GE Healthcare, Madison, WI, USA; 4Biomedical Engineering, University of Wisconsin, Madison, WI, USA

This study was performed to demonstrate improvements in the quality of fat suppression for fast spin-echo (FSE) imaging of the knee using multi-peak fat spectral modeling and IDEAL fat-water separation. T1-weighted and T2-weighted FSE sequences with single-peak and multi-peak IDEAL fat-water separation and 2 frequency-selected fat-saturation methods (fat-selective saturation and fat-selective partial inversion) were performed at 3.0T in 10 knees of 5 asymptomatic volunteers. Multi-peak IDEAL had significantly greater (p<0.05) suppression of signal of subcutaneous fat and bone marrow than fat-selective saturation, fat-selective partial inversion, and single-peak IDEAL for both T1-weighted and T2-weighted FSE sequences.

14:30         3960.     A Novel Algorithm for Eddy Current Effect Elimination in Three Points Dixon Method

Wu DongMei1, Dai YongMing2

1Siemens Mindit Magnetic Resonance Ltd, ShenZhen, GuangDong, China; 2Siemens Ltd., China, Shanghai Branch Medical Solutions Group, ShangHai, China

For "bipolar" mode dixon method, we know that eddy current is serious when gradient polarity alternates quickly. For eddy current will misalign the k-space, which leads to a linear phase discrepancy for different echo image. The discrepancy will disrupt the chemical-shift induced phase difference,finally lead to the failure of fat water separation for dixon method. In this abstract, we represent a novel algorithm to correct the misalignment efficiently in image space.

15:00         3961.     An Iterative Algorithm Method for T2 Mapping

Weiwei Zhang1, Yongchuan Lai1, Wenhua Che1

1GE Healthcare, Beijing, China

In this study, we show an iterative algorithm method for T2-mapping based on fast spin echo (FSE) acquisition. When 180 refocusing pulse is inaccurate, T2 estimation will also be inaccurate due to stimulated echoes. Such error is compensated here by calculating effective flip angle of refocusing pulse for every pixel.

 
Exhibit Hall 2-3                    Tuesday 13:30-15:30          Computer 55

13:30         3962.     Comparison of IDEAL, MultiPeak IDEAL and Fat-Saturated FSE for Imaging of Osteoarthritis (OA) Knee Patients: Initial Clinical Experience

Jian Zhao1,2, Radu Bolbos1, Ann Shimakawa3, Huanzhou Yu3, Xiaojuan Li1, Sharmila Majumdar1, Thomas Link1

1Radiology Department, University of California San Francisco, San Francisco, CA, USA; 2Radiology Department, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, China; 3GE Healthcare – ASL West, Menlo Park, CA, USA

Iterative Decomposition of Water and Fat with Echo Asymmetry and Least-Squares Estimation (IDEAL) is a promising MRI technique for robust fat and water separation. The goal of this study is to assess image quality, fat suppression and fat-water separation of single-peak (SP) and multiple-peak (MP) IDEAL imaging to fat saturated fast spin-echo (FSE) imaging in knee osteoarthritis (OA) patients. Twenty knee OA patients underwent MRI at 3T. Fluid-cartilage contrast-to-noise ratio (CNR) efficiency was significantly higher for SP IDEAL and MP IDEAL compared with FSE imaging. IDEAL sequence can provide excellent contrast between cartilage and fluid and MP shows better image quality.

14:00         3963.     Temporal Dynamics of Gd-Enhaced T1 Relaxation Time in Deep and Superficial Femoral Articular Cartilage

Zana Hawezi1, Carl Johan Tiderius2, Jonas Svensson3, Leif E. Dahlberg2, Eveliina Lammentausta1

1Joint and Soft Tissue Unit, Department of Clinical Sciences, University of Lund, Malmö, Sweden; 2Department of Orthopaedics, University of Lund, Malmö, Sweden; 3Department of Radiation Physics, University of Lund, Malmö, Sweden

dGEMRIC technique has been developed to assess GAG content of articular cartilage. T1 relaxation time of femoral articular cartilage was measured before Gd-DTPA administration and 1, 2, 3 and 4 hours after triple dose Gd-DTPA administration. The most superficial and deep regions were analyzed. Before contrast agent administration, T1 values of deep and superficial cartilage differed from each other. Also the change of deep and superficial T1 as a function of time was different. By analyzing dGEMRIC results separately for deep and superficial cartilage, additional information about cartilage could be obtained.

14:30         3964.     Reduction of the Magic Angle Effect on Contrast in Magnetization Transfer Imaging of Human Cartilage

Weiguo Li1, Jun Li2, Carol Muehleman2, Richard Magin1

1Bioengineering, University of Illinois at Chicago, Chicago, IL, USA; 2Biochemistry, Rush University Medical Center, Chicago, IL, USA

In MRI, magic angle (MA) effect visualizes as bright spots in e.g. collagen fibers of tendons and ligaments and often confounds accurate interpretation of these areas. However, very few studies were conducted to reduce the MA effect during imaging of cartilage in vivo. In this study, we tested the hypothesis that the MA effect is reduced more in MT-weighted images than in T2-weighted images using MR microscopy at 11.7 T on human cartilage plug. An in vivo investigation is being applied to verify the conclusions from this study.

15:00         3965.     Accelerated MR Protocol for Cartilage Volume Analysis and ‘Whole-Organ” Joint Assessment for Osteoarthritis Research Studies

Vaishali Soneji Lafita1, Richard Kijowski1, David Rabago2, Michael Woods1, Dana Tudorascu3, Jessica Klaers4, Walter Block4,5

1Radiology, University of Wisconsin, Madison, WI, USA; 2Family Medicine, University of Wisconsin, Madison, WI, USA; 3Statistics, University of Wisconsin, Madison, WI, USA; 4Medical Physics, University of Wisconsin, Madison, WI, USA; 5Biomedical Engineering , University of Wisconsin, Madison, WI, USA

This study was performed to determine whether an 8 minute accelerated MR protocol consisting of isotropic resolution VIPR-SSFP and sagittal fat-suppressed T2-weighted FSE sequences could be used to provide rapid cartilage volume analysis and “whole-organ” joint assessment for osteoarthritis research studies. Cartilage volume measurements and “whole-organ” joint assessment using the WORM system were performed on 20 patients enrolled in an osteoarthritis research study using a 20 minute standard MR protocol and the accelerated MR protocol. There was a small mean difference of 0.27cm3 between cartilage volume measurements and strong correlation between WORM scores obtained using the standard and accelerated protocols.

 
Exhibit Hall 2-3                    Wednesday 13:30-15:30          Computer 55

13:30         3966.     Quantification of 3D Radial Undersampling Artifact to Obtain High Quality Isotropic Resolution (0.36 Mm) for Volumetric Cartilage Assessment

Jessica L. Klaers1, Ethan K. Brodsky1,2, Walter F. Block1,3

1Medical Physics, University of Wisconsin - Madison, Madison, WI, USA; 2Radiology, University of Wisconsin - Madison, Madison, WI, USA; 3Biomedical Engineering, University of Wisconsin - Madison, Madison, WI, USA

It has been suggested that precise cartilage volume measurements used in longitudinal studies of cartilage degeneration and treatment measurements require an in-plane resolution on the order of 0.3mm. While 3D radial SSFP methods have proven to be powerful for cartilage assessment by consistently providing 0.47mm isotropic resolution in 5 minutes, the effects of further increasing the resolution by increasing undersampling are poorly understood. We examine the impact of varying the undersampling factor for a given resolution and scan time to obtain high isotropic resolution for cartilage volume measurements. Preliminary results utilizing new scanner technology demonstrate higher image quality than previously attainable at high resolution.

14:00         3967.     Comparison of Different Quantitative Approaches in T Relaxation Time Assessment of the Knee

Yukihisa Takayama1, Masamitsu Hatakenaka1, Ken Okazaki2, Takashi Yoshiura1, Kei Nishikawa3, Tomoyuki Okuaki4, Ivan Zimine4, Hiroshi Honda1

1Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; 2Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; 3Radiology Center, Kyushu University Hospital, Fukuoka, Japan; 4Philips Electronics Japan, Tokyo, Japan

Magnetic resonance (MR) imaging for cartilage assessment provides useful information without invasive procedure. In addition to morphologic assessment, MR imaging can evaluate the biochemical properties of articular cartilages using various parameters. T1r relaxation time can be used to assess the glycosaminoglycan content of articular cartilage. However, the time required for MR examination can be disadvantageous for the patient. In this study, we assessed a simplified T1r relaxation time calculation method using only two different T1r prepared images, which can decrease the exam time. Additionally, we investigated the quality and efficacy of this method for diagnosing the knee.

14:30         3968.     Multicontrast Keyhole Imaging Enables Economy of Acquisition Time Up to 50% in Standard Diagnostic MRI-Knee Protocols.

Uwe Schuetz1, Axel Bornstedt2, Volker Rasche2

1Diagnostic and Interventional Radiology, University of Ulm, Ulm, Germany; 2Internal Medicine II, University of Ulm, Ulm, Germany

Based on MRI of the knee joint, it is demonstrated, how the use of a specific multi-contrast keyhole imaging technique that uses high- and low-frequency components of the k-space for different contrast weightings separately, can produce substantial time savings up to 50% in native diagnostic MRI-knee protocol maintaining similar subjective contrast quality of individual sequences.

15:00         3969.     A Fat Saturated Proton Density-Weighted 3D-TSE-Sequence for MRI of the Knee at 3T – First Clinical Results

Mike Notohamiprodjo1, Annie Horng1, Matthias Pietschmann2, Wilhelm Horger3, Karin A. Herrmann1, Jaeseok Park3, Jose Garcia del Olmo Raya1, Maximilian F. Reiser1, Christian Glaser1

1Institute for Clinical Radiology, University Hospitals Munich, Munich, Bavaria, Germany; 2Department of Orthopedics, University Hospitals Munich, Munich, Bavaria, Germany; 3Siemens Medical Solutions, Erlangen, Bavaria, Germany

The purpose of this study was to technically and clinically evaluate knee-MRI at 3T with an highly-resolved isotropic fat-saturated(fs) proton-density-weighted(PDw) 3D-TSE-sequence. Ten healthy volunteers and 60 patients with meniscus- and cartilage-pathologies were examined with a PDw-fs-3D-TSE-sequence (voxel-size 0,533m3) with consecutive 3D-reconstruction. SNR, CNR, SNR-efficiency, detection of signal abnormalities and diagnostic confidence were compared to state-of-the-art 2D-TSE-sequences (voxel-size 0,362x0,3mmm3). The 3D-TSE-sequence provided excellent SNR-efficiency and adequate SNR and CNR. Detection and visualization of meniscus- and cartilage-pathologies was at least comparable to 2D-TSE-sequences. Correlation between both sequences was excellent. 3D-TSE-sequences with consecutive 3D-reconstruction may therefore become a valuable component of future knee-MRI-protocols.

 
Exhibit Hall 2-3                    Thursday 13:30-15:30          Computer 55

13:30         3970.     In Vivo Sodium MRI at 3.0T of Patients with Previous ACL Injury

Garry E. Gold1,2, Seungbum Koo1, Ernesto Starosweicki1, Ronald Watkins1, Brian A. Hargreaves1, Neal K. Bangerter3

1Radiology, Stanford University, Stanford, CA, USA; 2Bioengineering, Stanford University, Stanford, CA, USA; 3Electrical and Computer Engineering, Brigham Young University, Provo, UT, USA

Early osteoarthritis can occur in patients who have torn their anterior cruciate ligament (ACL). Sodium MRI correlates with glycosaminoglcan (GAG) in the articular cartilage. Using a custom coil and 3D cones sequence, we measured the signal in the sodium of the articular cartilage of 10 subjects with ACL tears between 2-10 years ago. We showed decreased sodium signal in the ACL-injured knees of our subjects compared to their contralateral knee. We also showed increased sodium signal in the medial compartment compared with the lateral compartment. Sodium MRI is a promising method for detection of early GAG loss in the knee.

14:00         3971.     In Vivo Follow-Up of Spontaneous Repair of Osteochondral Defects in Rabbit’s Patellar Groove with Quantitative MRI

Piia Kristiina Valonen1, Hertta Pulkkinen1, Virpi Tiitu1, Mikko Lammi1, Risto Ojala2, Miika Nieminen2, Ilkka Kiviranta3

1University of Kuopio, Kuopio, Finland; 2 Oulu University Hospital, Finland; 3University of Helsinki, Finland

T2-weighted imaging, T1-mapping, and dGEMRIC were used to follow spontaneous repair of osteochondral defect in rabbits. Lesions (&#8709; 4 mm, 3 mm in depth) were made into the patellar groove, and MRI was taken 1 week, 2, 4, and 6 months after surgery. Pre-contrast T1-values shortened significantly for cartilage and bone repair, with cartilage T1 approaching the value of intact tissue. The dGEMRIC index also showed a decreasing trend. MRI was successfully used to follow the properties of spontaneous repair tissue, but in six months it did not achieve the structure of intact cartilage, shown with MRI and histology.

14:30         3972.     Risk Factors of Adhesion After Autologous Chondrocyte Implantation of the Knee

Atsuya Watanabe1,2, Hiroshi Yoshioka1, Shuhei Ogino1, Tim Bryant3, Tom Minas3

1Department of Radiology , Brigham and Women's Hospital, Boston, MA, USA; 2Department of Radiology, Teikyo University Chiba Medical Center, Ichihara, Chiba, Japan; 3Cartilage Repair Center, Brigham and Women's Hospital

The aim of this study is to investigate risk factors of the development of joint adhesion after autologous chondrocyte implantation (ACI) of the knee. We reviewed 232patient cases with knee ACI operated on from 1995 June to 2006 December, which had undergone second-look arthroscopy after the initial ACI surgery. All patients were examined with magnetic resonance imaging before the second-look arthroscopy. Based on the results of this study, we conclude that the two and more grafts, implantation at patellofemoral joint, and additional lateral release procedure appear to be risk factors of adhesion after ACI of the knee.

15:00         3973.     T2 Relaxation Time of Matrix-Based Autologous Chondrocyte Transplantations (MACT) and Corresponding Healthy Cartilage of the Knee – a Prospective 2-Year Follow-Up Study

Annie Horng1, Matthias Pietschmann2, José Raya1, Peter Mueller2, Maximilian F. Reiser1, Christian Glaser1

1Department of Clinical Radiology, University Hospitals LMU Munich - Campus Grosshadern, Munich, Bavaria, Germany; 2Department of Orthopedic Surgery, University Hospitals LMU Munich - Campus Grosshadern, Munich, Bavaria, Germany

Experiences in quantitative T2 mapping of matrix-based autologeous chondrocyte transplantations (MACT) are only available from cross-sectional studies. This first prospective longitudinal study analyses T2 relaxation time of MACT and other cartilage compartments of the operated knee. Results support the clinical experience of continuous remodelling of MACT for 1-2y after operation before reaching normal T2 values. Transient T2 alterations are observed in the cartilage opposite to MACT which might be due to operational trauma or biomechanical changes in the joint. In summary T2 imaging provides a potential tool for postoperative monitoring of cartilage repair and might contribute to predict posttherapeutical evolution.

 


 
Cartilage:  Quantitative Techniques & Loading
Exhibit Hall 2-3                    Monday 14:00-16:00          Computer 56

14:00         3974.     Changes in T1ρ and T2 Relaxation Times of Tibiofemoral Articular Cartilage with Acute Loading

Richard B. Souza1, Radu I. Bolbos1, Brad T. Wyman2, Marie Pierre Hellio2, Thomas M. Link1, Xiaojuan Li1, Sharmila Majumdar1

1Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA; 2Pfizer Inc., New London, CT, USA

It is believed that cartilage loading plays a key role in the homeostasis of the cartilage biochemical environment. The objective of the current study is to determine the influence of acute mechanical loading on tibiofemoral cartilage T1rho and T2 relaxation times. Eight subjects were imaged on a 3T GE MR scanner under two conditions: unloaded, and loaded at 50% body weight. Acute loading resulted in statistically significant decreases in the medial compartment but not the lateral compartment for both T1rho and T2, suggesting that cartilage water concentration decreases and proteoglycan concentration increases.

14:30         3975.     T1ρ MRI of Human Articular Cartilage at 3T: Topographic Variations and Correlation with Indentation Biomechanical Properties

Won C. Bae1, Florian Buck1, Reni Biswas2, Eric Diaz1, Sheronda Statum1, Robert L. Sah2, Eric Han3, Jiang Du1, Christine B. Chung1

1Radiology, UC San Diego, San Diego, CA, USA; 2Bioengineering, UC San Diego, La Jolla, CA; 3Applied Science Lab West, GE Healthcare, Menlo Park, CA

 

15:00         3976.     T1ρ Assessment of Human Cartilage in an Impact Injury Model

Daniel Ross Thedens1, Sirisha Tadimalla2, James A. Martin2, Annunziato Amendola2, Douglas R. Pedersen2

1Radiology, University of Iowa, Iowa City, IA, USA; 2Orthopaedics and Rehabilitation, University of Iowa, Iowa City, IA, USA

T1ρ imaging has shown promise as a sensitive indicator of changes in proteoglycan (PG) content in tissues. In this study, a single mechanical impact model was used to observe the PG changes in fresh human cartilage and to assess the ability of T1ρ imaging to accurately detect and portray PG depletion. T1ρ relaxation correlated well with PG measurements, furthering the hypothesis that PG depletion resulting from mechanical impact or injury can be assessed noninvasively with T1ρ imaging.

15:30         3977.     Bone Marrow Edema-Like Lesions and Cartilage Degeneration in Osteoarthritis Using 3T MR T1ρ Quantification: Longitudinal Assessment

Jian Zhao1,2, Radu Bolbos1, Sharmila Majumdar1, Thomas Link1, Xiaojuan Li1

1Radiology Department, University of California San Francisco, San Francisco, CA, USA; 2Radiology Department, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, China

Bone marrow edema-like lesions (BMEL) has been associated with the severity and progression in osteoarthritis (OA). The goal of this study was to quantitatively assess the spatial relationship between BMEL and the associated cartilage in knee OA using MR T1rho quantification. Twelve OA patients were scanned at 3T at baseline and one-year follow-up. Both T1rho values and WORMS grading were significantly elevated in cartilage overlying BMEL (OC) compared to surrounding cartilage (SC). From baseline to one-year follow-up, T1rho increase in OC were significantly higher than that in SC. This preliminary data suggested BMEL is indicative of accelerated cartilage degeneration.

 
Exhibit Hall 2-3                    Tuesday 13:30-15:30          Computer 56

13:30         3978.     Detection of Degenerative Cartilage Disease: Comparison of High Resolution Morphological MR and Quantitative T2 Mapping at 3.0 Tesla

Siegfried Trattnig1, Sebastian Apprich1, Pavol Szomolanyi1,2, Marius Mayerhoefer1, Katja Pinker1, Tallal C. Mamisch3, Goetz H. Welsch1,4

1Department of Radiology, Medical University of Vienna, MR Centre - Highfield MR, Vienna, Austria; 2Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia; 3Orthopedic Surgery Department, Inselspital Bern, Bern, Switzerland; 4Department of Trauma Surgery, University Hospital of Erlangen, Erlangen, Germany

Osteoarthrithis is a multifactorial and heterogeneous disease associated with a progressive loss of hyaline articular cartilage. The role of T2 mapping in different stages of cartilage degeneration is still not well defined.

14:00         3979.     Articular Cartilage Injury Associate with Acute Rupture of Anterior Cruciate Ligament Injury in the Knee: Assessment with T2 Mapping

Atsuya Watanabe1, Toshiyuki Okubo1, Haruyasu Yamada1, Tetsuya Kosaka1, Masamichi Takahashi1, Atsushi Nozaki2, Takayuki Obata3, Fumio Osone1, Yuichi Wada4

1Department of Radiology, Teikyo University Chiba Medical Center, Ichihara, Chiba, Japan; 2GE Healthcare; 3Department of Biophysics, National Institute of Radiological Sciences; 4Department of Orthopaedic Surgery, Teikyo University Chiba Medical Center, Ichihara, Chiba, Japan

The aim of this study is to evaluate the relation between acute anterior cruciate ligament (ACL) rupture and cartilage injury by use of quantitative magnetic resonance (MR) imaging technique, T2 mapping. Of the 47 patients with acute ACL injury, 24 had a bone bruise at lateral femoral condyle. A significant increase in the T2 of cartilage at the femoral condyle with bone bruise was observed, while no significant increase in the T2 of cartilage at the femoral condyle without bone bruise was observed. The presence of bone bruise at lateral femoral condyle after acute ACL rupture was thought to indicate the presence of cartilage deterioration at that site.

14:30         3980.     Voxel-Wise Assessment of Pathology Evolution in Articular Cartilage Based on Statistically Significant Changes of T2

Jose G. Raya1,2, Andreas Biffar, Annie Horng3, Olaf Dietrich, Yuko Fukuda4, Maximilian Felix Reiser3, Christian Glaser3

1Josef Lissner Laboratory for Biomedical Imaging, Department of Clinical Radiology, University of Munich, Munich, Germany; 2Josef Lissner Laboratory for Biomedical Imaging, Department of Clinical Radiology, University of Munich, Munich, Germany; 3Department of Clinical Raciology-Großhadern, Universisty of Munich; 4Department of Clinical Raciology-Großhadern, University of Munich

A new method for the assessment of the evolution of pathology at a voxel-basis in articular cartilage is proposed. The method bases in the detection of statistically significant changes in T2 in follow-up examinations. Datasets acquired at different times are first registered. For each voxel the differences in T2 are tested for significance using reproducibility data acquired in repeated examinations in patients and OA patients. Significant differences can be classified in 6 different evolutions, which provide new diagnostic information. The utility of the method is demonstrated in follow up examinations on 5 autologous chondrocyte transplantated patients.

15:00         3981.     Cartilage T2 of the Patella and Focal Knee Abnormalities at 3T in Relation to Physical Activity in Non Symptomatic Subjects from the Incidence Cohort of the Osteoarthritis Initiative

Christoph Stehling1,2, Hans Liebl1, Ben Hyun1, Nancy E. Lane3, Roland Krug1, Thomas M. Link1

1Department of Radiology, University of California, San Francisco, San Francisco, CA, USA; 2Department of Radiology, University of Muenster, Muenster, Germany; 3Department of Medicine, Aging Center, University of California Davis Medical Center, Sacramento, CA, USA

The aim was to study association of cartilage T2-relaxation-time-measurements, morphological cartilage and meniscus abnormalities using 3T MRI of the knee and physical activity levels obtained in 100 asymptomatic subjects aged 45-55 years from the OAI incidence cohort. Subjects had a very high prevalence of cartilage (79%) and meniscus (46%) lesions. A highly significant correlation between patella T2, severity of cartilage and meniscus lesions and physical activity levels was also found. Patella T2 may be a marker for internal joint derangement. Patients with higher activity levels and high T2 may be at greater risk for cartilage and meniscal abnormalities and for developing OA.

 
Exhibit Hall 2-3                    Wednesday 13:30-15:30          Computer 56

13:30         3982.     Combining Static and Dynamic MRI to Explain the Source of Patellofemoral Pain

Frances Theresa Sheehan1, Calista M. Harbaugh2, Nicole A. Wilson1, Abrahm J. Behnam1, Timothy J. Brindle1, Katharine E. Alter1

1Rehabilitation Medicine, National Institutes of Health, Bethesda, MD, USA; 2Biomedical Engineering Department, University of Michigan, Ann Arbor, MI, USA

Patellofemoral pain (PFP) syndrome is one of the most common problems of the knee. Typical symptoms are anterior knee pain, exacerbated by activities such as stair descent, prolonged sitting and squatting. Patellar maltracking is generally accepted as a leading causes of PFP. However, effective intervention has been hampered because the mechanical factors related to PFP are poorly understood. Thus, the primary objective of this study was to explore the possibility that numerous maltracking patterns exists within the umbrella term of maltracking in PFP. As an adjunct to this, the correlation between bone shape and PF kinematic was investigated.

14:00         3983.     In Vitro Correlation of MR Parameters Under Loading with Biomechanical Properties of Degenerated Articular Cartilage

Vladimir Juras1,2, Pavol Szomolanyi1,2, Zuzana Majdisova1,2, Irene Sulzbacher3, Stefan Gäbler4, Siegfried Trattnig1

1MR Centre / Highfield MR, Medical University of Vienna, Vienna, Austria; 2Department of Imaging Methods, Institute of Measurement Science, Bratislava, Slovakia; 3Clinical Institute of Pathology, Medical University of Vienna, Vienna, Austria; 4Inst. of Materials Science and Technology, TU Wien, Vienna, Austria

The purpose of this study was to compare MR parameters under loading with biomechanical properties of cartilage measured by indentation tests to show that the impact of biochemical changes in degenerated cartilage can be predicted by noninvasive imaging approach (MRI). In some cases, the correlation between MR and selected biomechanical parameters were relatively high, in particular T1 showed strong relation to the biomechanical parameters (T1 vs instantaneous modulus, r = 0.6324).

14:30         3984.     3D High-Resolution In-Vivo Cartilage Deformation of the Knee at 3T After Different Static Exercises Frequently Practised in Craftsman Professions

Annie Horng1, José Raya1, Monika Zscharn1, Ulrike Hoehne-Hückstädt2, Ingo Hermanns2, Ulrich Glitsch2, Rolf Ellegast2, Maximilian F. Reiser1, Christian Glaser1

1Department of Clinical Radiology, University Hospitals LMU Munich - Campus Grosshadern, Munich, Bavaria, Germany; 2Fachbereich 4, BGIA – Institut für Arbeitsschutz der Deutschen Gesetzlichen Unfallversicherung, Sankt Augustin, Germany

Repetitive static positions involving the knee joint might induce overuse and clinical symptoms related to osteoarthritis. This study evaluated extent and distribution of focal cartilage deformation of the knee after performing different frequently used positions in craftsman professions. Results indicate that HR-3D-MR-volumetry enables comprehension of significant change of cartilage deformation within the different cartilage plates. Also data provide references for contact zones and focal loading in various activities as well as information about reversibility of stress induced changes. Consideration of these findings may facilitate development of future preventive measures for labor protection, cartilage therapy as well as cartilage graft engineering.

15:00         3985.     In Vivo Effects of Unloading and Compression on T2 and T1Gd (DGEMRIC) Relaxation Times of Healthy Knee Articular Cartilage at 3 Tesla

Marius E. Mayerhoefer1, Goetz Welsch2, Tallal C. Mamisch3, Siegfried Trattnig

1Department of Radiology, Medical University of Vienna, Vienna, Austria; 2Medical University of Vienna, Austria; 3Inselspital Bern

We performed an in vivo assessment of the biochemical properties of healthy knee articular cartilage by means of T2 and T1Gd (dGEMRIC) mapping, to determine the effects of unloading and compression at 3.0 Tesla. Our results indicate that unloading has no significant effect on both T2 and T1Gd relaxation times. By contrast, compression leads to a small, significant increase of the T2 relaxation time, and to a more pronounced, significant decrease of the T1Gd relaxation time, in particular in the central, weight-bearing cartilage zones.

 
Exhibit Hall 2-3                    Thursday 13:30-15:30          Computer 56

13:30         3986.     Assessment of Interscanner and Intravendor Variability of T2 Relaxation Times of Cartilage in Human Tibia at 1.5T and 3T.

Yuko Fukuda1,2, Annie Horng1, Jose Raya3, Juergen Weber3, Reiichi Ishikura, Shozo Hirota, Maximilian F. Reiser1, Christian Glaser1

1Radiology, Klinikum Grosshardern, Munich, Germany; 2Hyogo medical college , Nishinomiya, Japan; 3Radiology, Josef Lissner Laboratory

The purpose of this study was to evaluate the influence of scanners and magnetic fields (1.5T and 3T) on global and regional T2 relaxation time of the tibial cartilage. Eight healthy volunteers were examined in 3 different 1.5T scanners and one 3T scanner (same manufacturer) using a coronal 3D-T1-w-FLASH-WE sequence and a fat-saturated multislice-multiecho-sequence (MSME). The results suggests T2 variability between 1.5T and 3T scanner were markedly larger as expected due to the field strength effect on T2 relaxation time. Therefore, ideally, only one scanner type should be used in studies of cartilage T2 in OA.

14:00         3987.     Differences in T2 Values of Knee Cartilage Measured with Different Scanners

Eveliina Lammentausta1, Juhani Multanen2, Miika T. Nieminen1,3

1Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland; 2Department of Health Sciences, University of Jyväskylä, Jyväskylä, Finland; 3Department of Radiology, University of Oulu, Oulu, Finland

To compare T2 results obtained from different scanners, the variability of relaxation times from scanners within and across manufacturers has to be known. In this study, T2 measurements of phantoms and human knee cartilage were compared between two scanner manufacturers and within three scanners from one manufacturer. Additionally, T1 of the phantom was measured. Significant variation in phantom T2 and T1 values were observed across scanner manufacturers. T2 measurements showed significant differences between scanner manufacturers, however, T2s within scanners from one manufacturer were similar. The differences are likely due to different features of the pulse sequences.

14:30         3988.     Use of a Dual-Echo Fast-Spin-Echo Sequence for T2 Mapping of Cartilage Within a Clinical Trial

Jonathan Karl Riek1, Edward A. Ashton1

1VirtualScopics, Inc., Rochester, NY, USA

T2 mapping has become a common method for analyzing the quality of cartilage tissue using MRI. The relationship between the collagen content of cartilage and the associated T2 relaxation time of the tissue has been studied extensively. The goal of this paper is to show the applicability of a dual-echo fast-spin-echo sequence within a clinical trial for T2 mapping of cartilage. The proposed sequence proves to be accurate for calculating T2 values in the range of 30 to 60ms, but increasingly inaccurate for longer T2 values. Therefore, it is an appropriate sequence for T2 mapping of cartilage.

15:00         3989.     Long-Term and Short-Term Reproducibility of T2 Relaxation Time in Human Knee Cartilage

Eveliina Lammentausta1, Ilkka Hannila1, Osmo Tervonen1,2, Miika T. Nieminen1,2

1Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland; 2Department of Radiology, University of Oulu, Oulu, Finland

he reproducibility of T2 relaxation time measurement in the femur, tibia and patella was investigated. The measurement session was repeated three times for nine healthy volunteers, and to calculate the short-term reproducibility, the measurement was repeated three times within a single session for four of the volunteers. Reproducibility was calculated for bulk cartilage at different joint surfaces and for deep and superficial cartilage at different topographical locations. The results were good, mean reproducibility being 4.1% long-time and 3.7% short-time for bulk, and 6.6% for smaller regions, both long-term and short-term.