Traditional Posters : Other
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Spectroscopic Quantification

Monday May 9th
Exhibition Hall  14:00 - 16:00

1381.   Cerebral glucose uptake in humans at hypoglycemic plasma levels follows reversible Michaelis-Menten kinetics  
Kim C.C. van de Ven1, Marinette van der Graaf1,2, Bastiaan E. de Galan3, Cees J.J. Tack3, and Arend Heerschap1
1Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands, 2Paediatrics, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands, 3General Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands

In this study human cerebral glucose content was determined during moderate hypoglycemia (~3 mM), in order to assess values of reversible MM kinetic parameters for glucose transport and compare this with previous data on glucose transport into the brain assessed during eu- and hyperglycemia. We found MM parameters Tmax/CMRglc = 2.93 and Kt = 3.27 mM, which is in agreement with previously published data in humans, and it is also in agreement with findings in rats under hypoglycemic conditions. We conclude that the reversible MM model is also valid at moderate hypoglycemic values.

1382.   Phase-Adjusted Echo Time (PATE)-Averaging: Application for glutamine resolution at 3.0 Tesla 
Andrew Paul Prescot1, Todd L Richards2, Stephen R Dager2, and Perry Franklin Renshaw1
1Brain Institute, University of Utah, Salt Lake City, UT, United States, 2Radiology, University of Washington, Seattle, WA, United States

Proton (1H) magnetic resonance spectroscopy (MRS) investigations have reported altered glutamatergic neurotransmission in a variety of psychiatric disorders. The unraveling of glutamate from glutamine resonances is crucial for interpreting these observations although this remains challenging at clinical static magnetic field strengths. Glu resolution can be improved through an approach known as echo-time (TE)-averaging, which involves the acquisition and averaging of multiple TE steps. However, that method strongly attenuates Gln resonances. We have developed a novel approach termed phase-adjusted TE (PATE)-averaging for retrieving Gln signals from a TE-averaged 1H MRS dataset. Preliminary simulation and in vivo data are presented.

1383.   Area-Specific GABA Concentration Predicts Tactile Discrimination Performance In Humans 
Richard Anthony Edward Edden 1, Nick Adrianus Johannus Puts2, Christopher John Evans3, and David John McGonigle2,3
1Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, Baltimore, MD, United States, 2School of Biosciences, Cardiff University, Cardiff, United Kingdom, 3CUBRIC, School of Psychology, Cardiff University, Cardiff, United Kingdom

Deficits in GABAergic transmission and perceptual processing have been implicated in a number of neuropsychiatric disorders. Here we use MEGA-PRESS MRS and tactile psychophysics to investigate the relationship between in vivo GABA concentration and individual vibrotactile thresholds in humans at 3T. GABA concentration correlated with individual vibrotactile frequency discrimination thresholds in sensorimotor cortex (R = 0.58; p < 0.02) but not in occipital cortex (n.s.). This study shows that MEGA-PRESS MRS can be used to link measures of perceptual ability to neurotransmitter concentration in the somatosensory domain.

1384.   Quantification of glycine in the human brain by PRESS at 3T 
Changho Choi1, and Sandeep Ganji1
1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, United States

Glycine (Gly) in the healthy human brain has been measured at 3T using an optimized PRESS echo time, (TE1, TE2) = (60, 100) ms, which permitted detection of both Gly and myo-inositol (mI) with comparable selectivity. Metabolite concentrations were estimated with respect to the brain water concentration obtained from the GM and WM fractions within the voxel. From five normal subjects, the Gly and mI concentrations in the right parietal cortex were estimated to be 0.6¡¾0.1 mM and 4.3¡¾0.4 mM (mean¡¾SD, n=5), with mean CRLBs of 9¡¾1% and 5¡¾1%, respectively.

1385.   Multi-Channel Spectroscopic Imaging Reconstruction Using Water-Referencing with Compressed Sensing 
Maryam Vareth1,2, Eugene Ozhinsky1,2, and Sarah J. Nelson1,3
1Surbeck Laboratory of Advanced Imaging, Department of Radiology and Biomedical Imaging, Univ. of California, San Francisco, San Francisco, CA, United States, 2UCSF/UCBerkeley Joint Graduate Group in Bioengineering, Univ. of California, San Francisco, San Francisco, CA, United States, 3Univ. of California, San Francisco, Department of Bioengineering and Therapeutic Sciences, San Francisco, CA, United States

In this study we have implemented the compressed sensing algorithm with an efficient reconstruction technique to obtain optimal phase estimation for 3D MRSI using non-water suppressed spectra. Compressed sensing was shown to reduce acquisition time for water referencing spectra by 5x without negatively affecting the quality of phase estimation.

1386.   Quantitative 31P Magnetic Resonance Spectroscopy of the breast at 7 Tesla. 
Jannie Petra Wijnen1, Mariska P. Luttje1, Wybe J.M. van der Kemp1, Peter R. Luijten1, and Dennis W.J. Klomp1
1Radiology, University Medical Centre Utrecht, Utrecht, Utrecht, Netherlands

In this study we quantified the metabolite levels of phosphocholine and phosphoethanolamine in the breast of healthy volunteers. We used a dedicated 31P breast coil at 7T and used outer volume suppression to eliminate contributions from the chest muscle. The phosphomonoester signals had good SNR and were artifact free. With routine proton imaging and phantom calibration measurements the PME content could be quantified to absolute concentrations. The concentration found for PE and PC are within physiological range and agree with literature that report on total choline levels in the breast.

1387.   T2CSF pitfalls using water as internal reference for metabolite quantification 
Markus Sack1, Gabriele Ende1, and Wolgang Weber-Fahr1
1Neuroimaging, Central Institute of Mental Health, Mannheim, Germany

The internal water signal is often used as an internal reference for metabolite quantification. We conducted two T2 measurements for an anterior cingulate single voxel MRS location to determine the T2 times for BM and CSF. Spectra and T2maps were obtained from 23 subjects and fitted by a bi-exponential and a mono-exponential function, respectively. Both obtained datasets showed a strong dependency of the evaluated T2CSF values on the CSF content calculated by SegSpec. A computational model could mimic this dependency by overestimating the CSF content. Nevertheless, further investigations are necessary to discover the underlying mechanism or unknown additional compartment(s).

1388.   Impact of the prior knowledge on the quantification of in vivo 13C spectra using two different algorithms: LCModel and AMARES 
Cristina Cudalbu1, Bernard Lanz1, Joao M Duarte1, Nicolas Kunz1, and Rolf Gruetter1,2
1Laboratory for Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, 2Departments of Radiology, Universities of Lausanne and Geneva, Geneva, Switzerland

In the present study we assess the impact of the prior knowledge on the quantification of in vivo 13C spectra using two different algorithms: LCModel and AMARES combined with 4 different approaches to handle the prior knowledge. The results obtained with AMARES were identical with those obtained with LCModel if improved prior knowledge is used. We can conclude that additional prior knowledge used in AMARES leads to a more accurate and reliable quantification of in vivo 13C spectra. In contrast, when limited prior knowledge is used the results obtained with AMARES are over/underestimated.

1389.   Serial proton MRS of the human brain after oral administration of 12C and 13C enriched glucose 
Arabhi C Nagasunder1,2, Ashok Panigrahy1,3, Fawzi Boumezbeur4, Marvin D Nelson1, and Stefan Bluml1,2
1Radiology, Childrens Hospital Los Angeles, Los Angeles, CA, United States, 2Rudi Schulte Research Institute, Santa Barbara, CA, United States, 3Radiology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States, 4Commissariat à l’Energie Atomique, Institute for Biomedical Imaging, Gif-sur-Yvette, Paris, France

Regular glucose (12C Glc) and 13C enriched (U-13C) glucose was administered orally to healthy controls. MR spectra, using a standard PRESS sequence on a clinical 3T scanner, were acquired before and after Glc administration. Increased brain glucose concentrations were readily detectable after 12C Glc administration. When U-13C Glc was used, 13C label replaced 12C and resulted in an apparent reduction of the 1H MRS detectable breakdown products of glucose such as glutamate (Glu). This study demonstrates the feasibility of monitoring glucose metabolism in the human brain using widely available and FDA approved methods. Despite the limitations in specificity, this approach could be useful when the logistical challenges, posed by advanced approaches to study in vivo Glc metabolism, cannot be overcome.

1390.   An objective method for automated classification of brain tumors using Proton MR spectroscopy 
YU ZHANG1, Sanjeev Chawla1, Sumei Wang1, Sangeeta Chaudhary1, Jaroslaw Krejza1, E R Melhem1, and Harish Poptani1
1Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States

We investigated whether LC Model and linear discriminant analysis of the 1H MRS data from the contrast enhancing and peri-tumoral regions of the tumor can be used as an objective method for better classification of brain tumors. Linear discriminant analysis correctly classified 85% of 138 patients from six different brain tumor subtypes. Classification accuracies of glioblastomas versus metastases and astrocytomas versus oligodendrogliomas were 83% and 94% respectively. In comparison to previous 1H MRS studies, our study proposes a fully automated 1H MRS data analysis approach with minimum operator intervention and high diagnostic accuracy in brain tumor classification.

1391.   ERETIC based in vivo 1H MRSI quantification 
Niklaus Zoelch1, Susanne Heinzer-Schweizer2, Peter Boesiger1, and Anke Henning1
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, 2Philips AG Healthcare, Zurich, Switzerland

A modified ERETIC method has been developed to enable quantification of metabolite concentrations in proton spectroscopic images (MRSI). Together with the acquisition of a B1 map, an accurate quantification of absolute metabolite concentrations is achieved in vivo.

1392.   The influence of the external magnetic field strength on correlations between metabolites 
Reggie Taylor1,2, Peter Williamson1,3, and Jean Théberge1,2
1Medical Biophysics, University of Western Ontario, London, ON, Canada, 2Lawson Health Research Institute, London, ON, Canada, 3Psychiatry, University of Western Ontario, London, ON, Canada

Increasing the external magnetic field strength (B0) increases the SNR and spectral dispersion in a linear manner. Simulations were created to represent 4 B0 at 64 and 256 averages to examine how independent quantification of metabolites improves with B0. 200 noisy realizations were produced for each template and correlations between metabolites were extracted. Increasing B0 reduced the number of significantly correlated metabolites and in most cases reduced the magnitude of correlations. However, not all of the magnitudes of significantly correlated metabolites decreased as B0 increased. At equal SNR, precision increased by an average factor of 1.76 from 1.5T to 3T.

1393.   Mapping T2 Relaxation Time of Cerebral Metabolites using Three Dimensional Proton-Echo Planar Spectroscopic Imaging (PEPSI) 
Hsiang Wei Ho1, Shang Yueh Tsai1, Yi Ru Lin2, Stefan Posse3,4, and Fa Hsuan Lin5,6
1Electrical Engineering, Chang Gung University, Tao Yuan, Taiwan, 2Electronic Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan, 3Neurology, University of New Mexico School of Medicine, Albuquerque, NM, United States, 4Electrical and Computer Engineering, University of New Mexico, Albuquerque, NM, United States, 5Biomedical Engineering, National Taiwan University, Taipei, Taiwan, 66 MGH-HST Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, United States

Regional metabolite T2 relaxation times are necessary for absolute quantification of metabolite concentration. Here, 3-diemensional Proton-Echo-Planar-Spectroscopic-Imaging (PEPSI) is proposed to obtain T2 maps of three major cerebral metabolites in four consecutive slices in less than 20 minutes. Our results show consistent T2 values between subject and regional difference of NAA between WM and GM which in agreement with previous studies. The estimation of T2 values is stable according to the high Pearson’s correlation coefficients between logarithmic MR signals and TE. In summary, PEPSI technique is a robust method to obtain fast maps of metabolite T2 values.

1394.   Modeling MEGA-PRESS macromolecules for a better grasp of GABA 
James B Murdoch1, and Ulrike Dydak2,3
1Toshiba Medical Research Institute USA, Mayfield Village, Ohio, United States, 2School of Health Sciences, Purdue University, West Lafayette, Indiana, United States, 32Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, United States

GABA, a primary inhibitory neurotransmitter, is central to the understanding of many neurodegenerative and psychiatric disorders. The TE 68 MEGA-PRESS sequence has proven to be a reliable technique for measuring GABA at 3T, but subsequent analysis is frequently complicated by the presence of a co-edited macromolecule peak at 3.0 ppm (“MM30”). We have explored five different techniques for managing this macromolecular feature in LCModel. In particular, we have created and analyzed synthetic “metabolite-nulled” spectra to obtain a new set of MM functions appropriate for MEGA-PRESS difference spectra.

1395.   In vivo absolute quantification for mouse muscle metabolites using an inductively coupled synthetic signal injection method and newly developed 1H/31P dual tuned probe 
Donghoon Lee1, Kenneth Marro1, Mark Mathis1, Eric Shankland1, and Cecil Hayes1
1University of Washington, Seattle, WA, United States

We obtained robust estimates of 31P metabolite content in mouse muscles using a synthetic signal injection method and an optimized, 1H/31P dual tuned probe. 31P metabolite concentrations obtained from normal mice were well within the expected range reported in the literature. Our 1H/31P dual tuned probe was composed of two separate solenoid coils and each solenoid included a second coil to allow injection of pseudo signals. In addition to in vivo 31P metabolite quantitation, 1H MR imaging was conducted for both legs to perform parametric MRI along with muscle volume measurements.

1396.   Multi-variate pattern analysis for identification of metabolites that are predictive of malignant transformation in gliomas using HRMAS spectra from image guided tissue samples 
Alexandra Constantin1, Adam Elkhaled2, Trey Jalbert2, Radhika Srinivasan2, Soonmee Cha3, Susan M. Chang3, Ruzena Bajcsy1, and Sarah J. Nelson2
1Electrical Engineering and Computer Science, University of California, Berkeley, CA, United States, 2Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, United States, 3Department of Neurological Surgery, University of California, San Franisco, CA, United States

In this study, we applied multivariate pattern recognition methods to HRMAS spectra from image guided tissue samples in order to identify metabolites that are predictive of malignant transformations in gliomas and to accurately detect those patients exhibiting malignant transformations. Our method extracts a small subset of features in the HRMAS spectra and uses it to build a parsimonious model capable of discriminating between patients with different tumor grades with over 90% accuracy. The features used in our model are traced back to known metabolites in the corresponding chemical shift range, thus identifying a useful set of metabolites to acquire in-vivo.

1397.   Ex vivo ischemic kidney damage 23Na relaxometry 
Christoffer Laustsen1,2, Steffen Ringaard1, Mads Damkjær3, and Michael Pedersen1
1Klinisk Institut, The MR Research Centre, Aarhus University, Aarhus, Denmark, 2Danish Research Centre for Magnetic Resonance, Hvidovre Hospital, Hvidovre, Denmark, 3Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark

Sodium is a pivotal metabolite in the equilibrium cell state, and is therefore an ideal candidate as a biomarker for macroscopic damage, which is directly linked to the cellular alterations in the sodium gradient across the cell membrane. We here show the use of a simple relaxometry method for gaining additional insight in ex vivo organs. We show that it is possible to differentiate the healthy kidney from the diseased by 23Na-multi-component relaxation analysis.

1398.   Improved data analysis for two-dimensional J-resolved 1H-MRS: Application in brain tumors 
Changho Choi1, Sandeep Ganji1, and Elizabeth Maher2
1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, United States, 2Internal Medicine and Neuro-oncology, University of Texas Southwestern Medical Center, Dallas, Texas, United States

Two-dimensional (2D) J-resolved spectroscopy may provide improved resolution for J-coupled resonances compared to conventional 1D data acquisitions. Single-voxel localized PRESS (point-resolved spectroscopy) data were acquired at 32 echo times from the tumor mass and contralateral normal-brain regions of three glimablastoma patients. The 2D NMR data were analyzed with spectral fitting (LCModel), using basis sets prepared with numerical calculation of model spectra that incorporated the actual parameters identical to those used in the data acquisition.

1399.   GABA Fitting for MEGA-PRESS Sequences with Different Selective Inversion Frequencies 
Zaiyang Long1,2, James Brown Murdoch3, Jun Xu1,2, and Ulrike Dydak1,2
1School of Health Sciences, Purdue University, West Lafayette, IN, United States, 2Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, United States, 3Toshiba Medical Research Institute USA, Mayfield Village, OH, United States

In this study, we compare three LCModel fitting techniques for the original MEGA-PRESS sequence and a modified “MM-symmetric” version which has editing pulses alternating between 1.9 ppm and 1.5 ppm. Fitting technique A yields the highest GABA concentrations with small CRLB values, but the concentrations are probably overestimated. Technique B with an added MM30 peak yields the lowest GABA concentrations with largest CRLB. Fitting technique C with a soft constraint on MM30 seems to work best for the original MEGA-PRESS sequence and technique A for the MM-symmetric version. GABA levels may deviate considerably if an inappropriate fitting approach is chosen.

1400.   Simple implementation of an inductively coupled synthetic signal injection method on a clinical MR scanner for absolute quantification 
Donghoon Lee1, Kenneth Marro1, Eric Shankland1, Mark Mathis1, Timothy Wilbur1, Gregory Wilson1,2, Jeff Stevenson1, Cecil Hayes1, and Kenneth Maravilla1
1University of Washington, Seattle, WA, United States, 2MR Clinical Science, Philips Healthcare, Cleveland, OH, United States

We report a simple way to implement an artificial signal injection method for absolute quantification on a clinical MR scanner. All injector RF components were placed in a shielded box that was isolated from the MR scanner circuitry so no hardware/software modifications were required for the implementation. We used the implemented injection device to acquire in vivo human muscle 31P MRS with a pseudo-signal acquired simultaneously. This approach is easy to implement with low cost hardware, making it attractive to a broad range of clinical and research MR sites.

1401.   Synthetic signal injection using a single RF channela 
Kenneth I Marro1, Donghoon Lee1, Eric G. Shankland1, C. Mark Mathis1, and Cecil E. Hayes1
1Radiology, University of Washington, Seattle, WA, United States

1402.   Quantitative Measurement of N-acetylaspartyl Glutamate (NAAG) at 3 Tesla Using TE-Averaged PRESS Spectroscopy and Lineshape Deconvolution 
Yan Zhang1, Shizhe Li1, Christine Rebsch1, Stefano Marenco1, and Jun Shen1
1National Institute of Mental Health, Bethesda, MD, United States

This abstract introduces a method whereby TE-averaged PRESS spectroscopy is used in conjunction with regularized lineshape deconvolution to measure N-acetyl-aspartyl-glutamate (NAAG). Averaging different echo times suppressed the signals of strongly-coupled multiple resonance lines near 2 ppm, including the signals of glutamate and the macromolecule MM20. The signal distortions were corrected by using lineshape deconvolution, and Tikhonov regularization was introduced to reduce the noise amplification arising from the deconvolution; as a result, spectral resolution could be enhanced without significantly sacrificing signal-to-noise ratio (SNR). The acetyl proton signal of NAAG was directly quantified by fitting the deconvoluted spectra, from 1.8 to 2.2 ppm, with a model that consisted of two Voigt-type lineshape peaks, yielding the NAAG-NAA ratio.

1403.   A multi-purpose simulator of coupled spin systems for MR localized spectroscopy and spectroscopic imaging 
Zenon Starcuk jr.1, Jana Starcukova1, and Danielle Graveron-Demilly2
1Magnetic Resonance and Bioinformatics, Institute of Scientific Instruments, Academy of Sciences of the Czech Republic, Brno, Czech Republic, 2Creatis-LRMN, Université Claude Bernard Lyon 1, France

The new simulator, implemented as a jMRUI plugin, addresses the needs of a practical spectroscopist as well as a pulse sequence physicist. Pulse sequences, optionally controlled by protocols, may include arbitrarily modulated RF and gradient pulses, cycles, overlapping pulses. Homo- or heteronuclear spin systems are described by spatial position, chemical shifts, J-coupling, and the Redfield relaxation matrix, whose parameters can be derived from simplified models (Solomon, component relaxivities of coherences). It can be used for the study of the effects of spectrally or spatially selective excitation, steady-state formation, magnetization transfer, pulse sequence optimization.

1404.   The Classification of In Vivo Proton Magnetic Resonance Spectroscopy of Brain Abscesses Using Principal Component Analysis (PCA) 
Ssu-Ying Lu1, Cheng-Wen Ko2, Tzu-Chao Chuang2, and Ping-Hong Lai3,4
1National Sun Yat-sen University, Kaohsiung, Taiwan, 2National Sun Yat-sen University, 3Veterans General Hospital-Kaohsiung, 4School of Medicine, National Yang-Ming University, Taipei, Taiwan

The interest in using proton MRS to identify the bacteria in pyogenic brain abscesses has been arising. In this study, we propose an algorithm using principal component analysis (PCA) to differentiate anaerobic and aerobic abscesses by means of in vivo short TE proton MR spectra. Our preliminary result shows PCA can be one potentially useful tool to distinguish various types of brain abscesses without any complicated post-processing algorithm. Our processing scheme may provide more precise analysis for MRS especially when macromolecular or strong lipid play an important role of clinical diagnosis.

1405.   Quantification of Rat brain metabolites by ProFit: Preliminary evaluation of high fat diet induced obesity 
Bhaskaran David Prakash1, Arunima Pola1, Na Agarwal1, and Sambasivam S Velan1
1Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, Singapore, Singapore, Singapore

ProFit based quantification has been demonstrated at 7T using localized max echo sampled J PRESS on the thalamus of rats on high fat vs placebo diets. Significant increase was detected in metabolic ratios with respect to creatine for NAA, alanine, glutamine, glutamate and lactate for the high fat group which could have implications for increased glucose metabolisms. None of the rats tested positive for insulin resistance. The results demonstrate ProFit’s ability to identify pre-diabetic markers. Creatine, alanine, aspartate, glycine, glucose, glutathione, lactate, myo-inositol and ascorbate shows lower Cramer-Rao lower bounds compared to 1D approach even at 16.1T.

1406.   Experimental Errors as Alternative to the Theoretical Cramér-Rao Minimum Variance Bounds in MRS: ER-ARSOS - Error Estimation by Multiple Quantification of Recombined ARSOS-filtered Output Signals 
Johannes Slotboom1, Dirk van Ormondt2, Olivier Scheidegger1, Caspar Brekenfeld1, Roland Wiest1, Gerhard Schroth1, and Danielle Graveron-Demilly3
1DRNN-DIN/SCAN, University Hospital Berne, Berne, Switzerland, 2Applied Physics, Delft University of Technology, Delft, Netherlands, 3Laboratoire Creatis-LRMN, Université Claude Bernard LYON 1, Lyon, France

The Cramer-Rao minimum variance bounds (CR-MVB) are widely used as estimates of errors in spectral-parameters in localized MRS. Due to the macromolecular baseline, non-analytical line-shapes, and artefacts resulting from non-stationary signal acquisition conditions or RF-pulse imperfections, the parametric model is normally incomplete, and, strictly taken, the CR-MVBs estimates invalid. In general the CR-MVB under-estimates the variances in the estimated spectral-parameters. This work presents a novel method named “ER-ARSOS” to estimate the experimental errors of the parameters, as an alternative to the CR-MVBs in MRS.

1407.   Cross-validation of PRESS, MEGA-PRESS editing and 2D JPRESS for neurotransmitter and antioxidant detection at 3T using the ERETIC reference standard 
Mariska Petra Luttje1, Michael Wyss1,2, Niklaus Zölch1,2, Alexander Fuchs1, Richard A.E. Edden3,4, Susanne Heinzer5, Peter Bösiger1, and Anke Henning1
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Zurich, Switzerland, 2Contributed equally, 3Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States, 4F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, United States, 5Philips AG, Zurich, Zurich, Switzerland

SV PRESS, MEGA-PRESS and localized 2D JPRESS are compared to investigate their ability of quantifying GABA, Glu, Gln and GSH accurately. ERETIC has been applied as a reliable reference. Next to this, for all sequences the metabolite ratios with the internal water reference were calculated. JPRESS shows to be the best method for simultaneous quantification of the selected metabolites, while MEGA-PRESS GABA-editing proofs to be a faster and reliable method for studies that target mainly GABA. The metabolite/ERETIC ratio shows to be a more stable and hence reliable quantification method compared to the metabolite/water reference ratio for all tested sequences.

1408.   Measuring tissue pH heterogeneity by 31P NMR spectroscopy 
Norbert W. Lutz1, Yann LeFur1, and Patrick J. Cozzone1
1Dept. of Medicine La Timone, Marseille, France

Pathological processes are likely to induce variations in tissue pH. Thus, reliable measurement of intra and extracellullar pH (pHi, pHe) should be very useful for the characterization of tissue metabolism. 31P NMR-based methods exist for pHi (chemical shift, δ, of endogenous Pi), and for pHe (δ of exogenous APP). However, the consequences of pH heterogeneity within a measured tissue volume have not been considered in these pH calculations. We suggest here three 31P NMR-based pH calculation methods that take into account the characteristics of the pH distribution under consideration.

1409.   Quantitative in vivo magnetic resonance spectroscopy using synthetic signal injection 
Kenneth I Marro1, Donghoon Lee1, Eric G. Shankland1, C. Mark Mathis1, Cecil E. Hayes1, and Martin J. Kushmerick1,2
1Radiology, University of Washington, Seattle, WA, United States, 2Physiology and Biophysics, University of Washington, Seattle, WA, United States

We have previously conducted in vitro measurements to demonstrate that conversion of MRS peaks to quantitative units of concentration can be efficiently achieved by using a second RF coil to inject a precalibrated, artificial reference signal into the data. In this work, we acquired 31P-MRS measurements from human tibialis anterior muscles and used pseudo-signal injection to determine PCr content. Our results demonstrate that pseudo-signal injection using inductive coupling provides a robust calibration factor that is immune to coil loading conditions and suitable for use in human measurements.

1410.   VeSPA: Integrated applications for RF pulse design, spectral simulation and MRS data analysis 
Brian J Soher1, Philip Semanchuk1, David Todd2, Jeffrey Steinberg1,3, and Karl Young2
1Radiology, Duke University Medical Center, Durham, NC, United States, 2Radiology, Northern California Institute of Research and Education, San Francisco, CA, United States, 3Singapore Bioimaging Consortium, Agency for Science, Technology and Research

The VeSPA-Versatile Simulation, Pulses and Analysis package is an integrated set of open source applications written in Python that enable users to 1) synthesize RF pulses, 2) explore MRS data acquisition scenarios using multi-parametric spectral simulation and 3) improve processing/analysis of MRS data. VeSPA’s RFPulse, Simulation and Analysis applications are written in Python and integrated through a SQLite database. Applications are based on previous programs, MatPulse, GAVA and SITools. Scientific functionality was ported into a common infrastructure to ease access (no license fees), simplify extension (open source) and to create a consistent style across applications and platforms.

1411.   Repeatability of 2D Magnetic Resonance Spectroscopic Imaging 
Lawrence Kenning1, Martin Lowry1, David John Manton1, and Lindsay W Turnbull1
1Centre for MR Investigations, University of Hull, Hull, United Kingdom

A repeatability study comparing the effects of field strength, pulse sequence and echo time was conducted. Data were acquired from ten volunteers on three occasions, using the mean of the differences between voxels to determine repeatability. An ANOVA model was used for statistical analysis (type IV). An interaction between field strength and echo time was found with shorter echo times being more repeatable at 3.0T, and longer echo times being more repeatable at 1.5T. Chemical shift dispersion is one possible cause. Robustness (no. good quality voxels/repeatability) was calculated and a relationship between theoretical SNR and robustness was found.

1412.   New Technique for Metabolite Cycled Non-Water-Suppressed Proton Spectroscopy in the Human Brain at 7T 
Erin Leigh MacMillan1, Roland Kreis1, Alex Fuchs2, Maarten J Versluis3, Chris Boesch1, Peter Boesiger2, and Anke Henning2
1Dept. of Clinical Research, University of Bern, Bern, Bern, Switzerland, 2Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Zurich, Switzerland, 3Dept. of Radiology, Leiden University Medical Center, Leiden, Netherlands

Non-water-suppressed MRS via metabolite cycling in the mixing period of STEAM was introduced to benefit from the ability to perform corrections on individual FIDs to increase SNR, and to provide a new tool to investigate exchangeable protons. At 7T, this technique successfully reduced the gradient sideband artifacts and water baseline tail to well below the prominent upfield peaks, and showed the same information as VAPOR water-suppressed spectroscopy. Furthermore, the 7.9ppm NAA peak was much better resolved with metabolite cycled non-water-suppressed MRS at 7T when compared to previous work at 3T.

1413.   Detection Strategies at 7 Tesla Using Clinical MRS Pulse Sequences 
Subechhya Pradhan1,2, John C. Gore2,3, and Kevin W. Waddell3,4
1Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, 37232, United States, 2Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, United States, 3Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States, 4Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, United States

Increased resolution and higher sensitivity at high field require re-evaluation of protocols to optimize data quality. Inspection of signal information surfaces as a function of resolution and echo-time in PRESS show that precision optima for inositols and amino acids are mutually exclusive, and thus cannot be measured optimally at a single echo. Three cases to consider are: 1) methyl-bearing molecules should be acquired at short TE to avoid T2 loss, 2) amino acids (Glu/Gln) at 109 and mI/sI at 30/78 ms (mI), and 3) for amino acids and inositols, the optimum strategy is to combine 30 and 109 ms echoes.

Traditional Posters : Other
Click on to view the abstract pdf and click on to view the pdf of the poster viewable in the poster hall.
Spectroscopy Localization

Tuesday May 10th
Exhibition Hall  13:30 - 15:30

1414.   Hadamard Encoding of 2D-Selective RF Excitations for Simultaneous Acquisition of Multiple, Irregularly Shaped Voxel in MR Spectroscopy 
Martin G Busch1,2, and Jürgen Finsterbusch1,2
1Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, 2Neuroimage Nord, University Medical Centers Hamburg-Kiel-Lübeck, Hamburg-Kiel-Lübeck, Germany

2D-selective RF (2DRF) excitations are able to excite arbitrarily shaped regions-of-interest within the plane defined by their trajectory. They have been applied to single-voxel MR spectroscopy to minimize partial volume effects by using an excitation profile that matches the shape of the desired target region. In this study, it is shown that Hadamard encoding of different target regions can be used to acquire multiple, irregularly shaped voxel simultaneously which increases the SNR efficiency accordingly. Experiments in a dedicated phantom using segmented, blipped-planar 2DRF excitations demonstrate that the different ROIs can be eliminated reliably.

1415.   Segmented 2D-Selective RF Excitations with Weighted Averaging and Flip Angle Adaptation for MR Spectroscopy of Irregularly Shaped Voxel 
Jürgen Finsterbusch1,2, and Martin G. Busch1,2
1Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, 2Neuroimage Nord, University Medical Centers Hamburg-Kiel-Lübeck, Hamburg-Kiel-Lübeck, Germany

A weighted averaging scheme with flip angle adaptation is presented and applied to single-line segments of a 2D-selective RF excitations based on a blipped-planar trajectory. Segments covering central k-space lines with significant signal contributions are averaged more often than outer segments with low flip angles and minor signal contributions. For compensation, these outer segments are acquired with a larger flip angle such that an unaltered signal contribution is obtained in a reduced number of shots. This improves the signal efficiency considerably as is demonstrated for MR spectroscopy of irregularly shaped, target-matched single voxel in the human brain in vivo.

1416.   Lactate Detection Using Double Quantum Coherence Filtering with Spectral-Spatial Refocusing RF Pulses in a PRESS Sequence 
Haoyang Xing1,2, Yi Sui1, Qiyong Gong3, and Xiaohong Joe Zhou1,4
1Center for MR Research, University of Illinois Medical Center at Chicago, Chicago, Illinois, United States, 2College of Physical Science and Technology, Huaxi MR Research Center, Sichuan University, Chengdu, Sichuan, China, People's Republic of, 3Huaxi MR Research Center, West China Hospital of Sichuan University, Chengdu, Sichuan, China, People's Republic of, 4Departments of Radiology, Neurosurgery, and Bioengineering, University of Illinois Medical Center at Chicago

Double-quantum coherence filtering (DQF) with PRESS localization has been used for lactate detection. The conventional techniques however suffer from spatial mismatch arising from chemical shifts. We have developed a DQF-PRESS technique using spatially and spectrally (SPSP) selective refocusing RF pulses to eliminate the spatial mismatch and improve lactate detection. This approach offered an approximately two-fold gain in signal-to-noise ratio, and successfully detected the lactate signal change in presence of excessive lipid signals in human subjects at 3T.

1417.   Accelerated 1H-MRSI: Artifact Reduction by Target-Driven Reconstruction 
Thomas Kirchner1, Anke Henning1, Klaas Paul Pruessmann1, and Peter Boesiger1
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland

In parallel 1H MRSI, artifacts detrimental to spectral quality can be due to low sampling resolution and residual aliasing. We therefore introduce a novel reconstruction method that minimizes the deviation from a predefined target shape for the spectral response function (SRF). Based on undersampled 3T in vivo MRSI data, we demonstrate that by this method, a significant reduction in spectral contamination originating from subcranial fat can be achieved. In particular, Gaussian target shapes lead to vastly improved fat artifact suppression compared to standard reconstruction.

1418.   Spectroscopic Imaging Using Concentrically Circular Echo-Planar Trajectories 
Jon Furuyama1, Neil Wilson1, and M. Albert Thomas1
1Radiology, UCLA, Los Angeles, CA, United States

Echo-Planar Spectroscopic Imaging (EPSI) is the acceleration technique of choice for chemical shift imaging, but due to hardware constraints, is limited low spectral bandwidths, which can create severe spectral aliasing. We propose a novel Spectroscopic Imaging using CONcentrically Circular Echo-Planar Trajectories (SI-CONCEPT), which, being gentler on the hardware, is capable of producing spectra with higher bandwidths, making this technique suitable for higher magnetic fields. We demonstrate the feasibility on a healthy human volunteer, showing that the use of concentrically circular k-space trajectories accurately encodes both spatial and spectral information.

1419.   Algorithm for Lipid Suppression by Real-Time Isotropic Filter Design in Spectroscopic Brain Imaging 
Joonsung Lee1, and Elfar Adalsteinsson1,2
1Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States, 2Harvard-MIT Division of Health Sciences and, Massachusetts Institute of Technology, Cambridge, MA, United States

Estimates of brain metabolites using MRSI are severely hampered by strong lipid signals even though the interfering signal arises from regions outside of the brain. Variable-density sampling of k-space with accompanying proportional filtering reduces the spatial side-lobes within the brain due to the extra-brain lipid sources. We present an improved algorithm that achieves a direct design of a subject-specific, optimal, spherically symmetric spatial filter in two or three dimensions to minimize lipid contamination estimated by pre-scans. The proposed method is demonstrated with single-slice MRSI to achieve 30~40 dB or lipid suppression in the absence of OVS or inversion recovery pulses.

1420.   Reproducibility and variance of serial short echo time 1H magnetic resonance spectroscopic imaging of the human brain at 3T with automated planning software 
Sofie Van Cauter1, Diana Sima2, Leon ter Beek3, Jan Luts2, Yuqian Li4, Maria Isabel Osorio Garcia2, Stefan Sunaert1, Sabine Van Huffel2, and Uwe Himmelreich5
1Department of Radiology, University Hospitals Leuven, Leuven, Belgium, 2Department Electrical Engineering – ESAT/SCD, Catholic University Leuven, 3Philips Medical Systems, 4School of Electronical Engineering, University of Electronic science and technology of China, Chengdu, China, People's Republic of, 5Biomedical NMR Unit/Molecular Small Animal Imaging Center, Department of Medical Diagnostic Sciences, Catholic University Leuven

The clinical value of MRSI has been limited due to long examination times and the lack of robust repositioning methods. In this study, we validate the reproducibility of a rapid 2D CSI PRESS protocol in two different 3T MR scanners in our institution. Furthermore, we investigate the potential role of automated repositioning software. The applied automated repositioning method proved to be a very robust which is of utmost importance in conducting longitudinal studies. Our MRSI acquisition protocol is a reproducible acquisition scheme when taken into account the chemical shift displacement effect and a careful interpretation of metabolites signals with low SNR.

1421.   High-resolution 1H-FID-MRSI of the human brain at 7T 
Wolfgang Bogner1, Stephan Gruber1, Siegfried Trattnig1, and Marek Chmelik1
1MR Center of Excellence, Department of Radiology, Medical University of Vienna, Vienna, Austria

This work describes a new approach for high spatial resolution 1H-MRSI of the human brain at 7T in vivo. The presented method is based on free induction decay (FID) acquisition with an ultra-short echo time (TE) of 1.3ms. This allowed the acquisition of a 64×64 matrix in 30 min measurement time. High quality metabolic maps with 3.4×3.4×12 mm resolution were obtained not only for NAA, Cho, and Cr, but even for Glu, and mI, due to the ultra-short TE. Our approach is insensitive to T2 decay, J-modulation, B1 inhomogeneities, CSDEs, and overcomes SAR restrictions at ultra-high magnetic fields. This makes it a promising method for high resolution 1H-MRSI at 7T and above.

1422.   Composite Localization with adiabatic slice selective excitation and refocusing (cLASER) for improved 1H MRSI in non uniform B1 fields 
Catalina Sofia Arteaga de Castro1,2, Uulke A. van der Heide1, Marco van Vulpen1, Peter R. Luijten2, and Dennis W.J. Klomp2
1Radiotherapy, UMC Utrecht, Utrecht, Utrecht, Netherlands, 2Radiology, UMC Utrecht, Utrecht, Utrecht, Netherlands

Due to strong B1 field non uniformities at higher fields, measurements like MR spectroscopy can be difficult to obtain with a good localization. We have included a composite slice selective adiabatic excitation in a sLASER sequence (cLASER) to reduce SAR deposition and the TE while preserving total adiabaticity of the sequence. In-vivo results are shown in the human prostate to illustrate the cLASER performance.

1423.   Short-echo spin-echo localization MRSI in gliomas at 7 Tesla 
Yan Li1, Albert P Chen2, Peder Larson1, Eugene Ozhinsky1, Janine M Lupo1, Duan Xu1, and Sarah J Nelson1,3
1Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, United States, 2GE Healthcare, Toronto, ON, Canada, 3Department of Bioengineering and therapeutic sciences, University of California, San Francisco, CA, United States

The purpose of this study was to implement a short echo MRSI acquisition at 7 Tesla. Data from phantom, healthy volunteers and patients with gliomas were acquired. The 2D H-1 MRSI was localized using spin echo with TE/TR = 30/2000 ms and spectral array = 20x20. MRSI data of good quality were demonstrated, and this method may be applied in a larger study of patients with gliomas to assess whether it provides additional information compared to the conventional MRSI acquisitions at 3T and 7T.

1424.   Short Echo-Time MRSI of Human Brain at 7 Tesla with Improved Shimming and Fat-Suppression 
Indrajit Saha1,2, Jay Moore1,3, Saikat Sengupta1,4, Subechhya Pradhan1,3, James M. Joers5,6, and John C. Gore1,2
1Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States, 2Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, United States, 3Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, United States, 4Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States, 5Department of Radiology, Children’s Hospital of Wisconsin, Milwaukee, WI, United States, 6The Medical College of Wisconsin, Milwaukee, WI, United States

The acquisition of high quality MR spectroscopic imaging data at 7 T requires overcoming several problems associated with the physics of high field MRSI. We present our ongoing work on developing 2-D/single-slice MRSI methodology at 7 T human MR system by using image-based shimming, and B1-insensitive composite-pulses for improved skull-lipid suppression in a short echo-time STEAM sequence. This preliminary work shows the promises of improvements achievable at 7 T for exploitation of SENSE acceleration in MRSI acquisitions.

1425.   Short Acquisition Time 3D High Resolution (1cc) In Vivo Brain 1H MRSI using LASER-RSI 
Claudiu Schirda1, Ovidiu Andronesi2, Tiejun Zhao3, Gregory Sorensen2, and Fernando Boada1
1Radiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States, 2Radiology, Massachusetts General Hospital, Boston, MA, United States, 3Siemens Medical Solutions, United States

We combine Rosette Spectroscopic Imaging (RSI), which is a fast, high sensitivity acquisition technique, with LASER , a high performance excitation scheme, and use a 32-channel phased array coil at high field (3T), to achieve high resolution (1cc) 1H MRSI (Magnetic Resonance Spectroscopic Imaging) data in vivo human brain.

1426.   Hadamard Encoded 3D MRSI of Human Brain at 7T 
Hoby Patrick Hetherington1, Nikolai I Avdievich1, Oded Gonen2, and Jullie W Pan1
1Neurosurgery, Yale University, New Haven, CT, United States, 2Radiology, New York University, New York, NY, United States

At 7T in the human brain reduced RF amplitude and increased spectral dispersion result in chemical shift dispersion (CSD) artifacts that can distort metabolite ratios. However, for 3D acquisitions CSD artifacts during slab selection corrupts the most superior and inferior slices manifesting as artifactually large and small NAA/Cr ratios. Hadamard encoding in the slab direction minimizes this error by providing multiple thin slices with minimal CSD effects, increasing spatial overlap of the Cr and NAA volumes, thereby increasing the overlap of NAA and CR volumes from <40% (conventional 3D CSI) to 92.5%.

1427.   Simultaneous up- and downfield spectroscopy using SPECIAL at 7T 
Alexander Fuchs1, Anke Henning1, Mariska P Luttje1, Maarten J Versluis2, Roland Kreis3, and Peter Boesiger1
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, 2Dept. of Radiology, Leiden University Medical Center, Leiden, Netherlands, 3Dept. of Clinical Research, University of Bern, Bern, Switzerland

Beside the commonly investigated resonances between water and lipids there is also a growing interest to detect and quantify metabolite signals on the downfield part of the spectrum (4.7-8ppm). However, measuring up- and downfield resonances in the same spatial region simultaneously involves a few problems. In this work, it is shown that inner volume saturation can be used to control the rather large chemical shift displacement artifact between 1.33 and 8ppm while SPECIAL localization offers short echo times and sufficient SNR to detect and quantify also the downfield resonance at 7T.

1428.   3D GABA Spectroscopic Imaging using MEGA-PEPSI 
Ulrike Dydak1,2, Jun Sai Xu1,2, Malgorzata Marjanska3, and Stefan Posse4,5
1School of Health Sciences, Purdue University, West Lafayette, IN, United States, 2Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, United States, 3Center for Magnetic resonance Research and Department of Radiology, University of Minnesota, Minneapolis, MN, United States, 4Department of Neurology, University of New Mexico School of Medicine, Albuquerque, NM, United States, 5Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, NM, United States

3D GABA mapping of the human brain is presented by combining the MEGA-editing scheme with the fast PEPSI spectroscopic imaging approach. In vivo data shows high data quality across several 1.5cm-thick brain slices, including coverage of cortical areas, allowing for reliable LCModel fitting of the GABA signal. 3D MEGA-PEPSI enables the acquisition of 32x32x8 difference spectra within only 17 min of scan time with a nominal voxel size of below 4ml, yielding GABA-edited spectra with similar SNR as achieved in single voxel scans and allowing for large anatomical coverage.

1429.   Whole Liver 31P Metabolite Mapping with 3D CSI 
Scott Jones1,2, Anshuman Panda1,2, and Ulrike Dydak1,2
1Health Sciences, Purdue University, West Lafayette, IN, United States, 2Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, United States

Use of an 8 channel Phased array coil for whole human liver 31P 3D MRSI.

1430.   Simultaneous Acquisition of Metabolites and Water Signals Using Multi-Coil Sensitivities 
Toru Shirai1, Satoshi Hirata1, Yoshihisa Soutome1, and Yoshitaka Bito1
1Central Research Laboratory, Hitachi, Ltd., Kokubunji, Tokyo, Japan

We have developed a technique for simultaneously acquiring metabolite and water signals in chemical shift imaging. This technique consists of measurement shifting only the water signal on the image, and the data process separating the metabolite and water signals using the coil sensitivity difference. Since the superimposed metabolites and water signals received from multiple coils can be separated using the coil sensitivity difference, both signals can be acquired simultaneously without increasing the scan time. The results from phantom experiments showed that this technique is useful for the simultaneous acquisition of metabolite and water signals without increasing the scan time.

1431.   Implementation of GOIA-Wurst pulse in a SPECIAL localization sequence at 7T 
Isabell Kristin Steinseifer1, Ralf Mekle2, Rolf Gruetter3, Tom WJ Scheenen1, and Arend Heerschap1
1Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands, 2Physikalisch-Technische Bundesanstalt, Berlin, Germany, 3LIFMET, Ecole Politechnique Federale de Lausanne, Lausanne, Switzerland

In 1H MRS the SPECIAL technique combines the advantages of ultra-short TE with full sensitivity obtained by SE based sequences. We present an adiabatic SPECIAL pulse sequence at 7T with two GOIA-W(16,4) pulses for refocusing. The GOIA-W(16,4) pulses provide a large bandwidth of 20 kHz and therefore make SPECIAL less sensitive to inhomogeneities and chemical-shift artefacts. We tested the SPECIAL-GOIA combination with a phantom and in vivo brain measurements. Even though TE is elongated by the implemented GOIA-W(16,4) pulses, it is still short enough to resolve coupled spin systems. We measured the same metabolites as with the original SPECIAL technique.

1432.   MRS localization in the human brain at 7T with adiabatic refocusing at short echo time using RF focusing with a dual channel volume transmit coil 
Vincent Oltman Boer1, Astrid L.H.M.W. van Lier2, Johannes M Hoogduin1, Jannie P Wijnen1, Peter R Luijten1, and Dennis W.J. Klomp1
1Radiology, UMC Utrecht, Utrecht, Utrecht, Netherlands, 2Radiotherapy, UMC Utrecht, Utrecht, Utrecht, Netherlands

In vivo localization of single voxel spectroscopy at short echo time in the human brain has shown to be challenging at 7T due to the limited bandwidth of refocusing RF pulses. In this work we show that by driving a standard volume coil with two RF amplifiers, focusing the B1+ field in a certain location, and using short high bandwidth adiabatic refocusing pulses, a semi-LASER localization is feasible at short echo time with full signal acquisition and a low chemical shift displacement artifact in the human brain at 7 tesla.

1433.   Single Voxel Spectroscopy in 5 year old children using an EPI vNav 
Aaron T. Hess1, André J.W. van der Kouwe2, and Ernesta M. Meintjes1
1MRC/UCT Medical Imaging Research Unit, Human Biology, University of Cape Town, Cape Town, South Africa, 2Radiology, Massachusetts General Hospital, Boston, MA, United States

The EPI volume navigator (vNav) is capable of measuring and correcting both head movement and B0 changes in real time. We assess the quality of spectra obtained using the vNav in 36 single voxel spectroscopy scans acquired from 14 five year old children in three different volumes of interest. Of the resulting 36 scans, four children moved enough to produce a 2 mm or greater shift in the voxel position. Despite these movements we obtained across all 36 scans linewidths between 2 Hz and 5 Hz. Further we demonstrate the motion, frequency and first order shim corrections applied by the vNav in one of scans where the child was particularly restless.

1434.   Signal Normalization for MR Spectroscopic Imaging Using Brain Tissue Water: Variability and Pathologic Detectability 
Mohammad Sabati1, Varan Govind1, and Andrew A Maudsley1
1Radiology, University of Miami, Miami, FL, United States

Several methods for calibration of brain MR spectroscopic imaging (MRSI) data have been proposed. Referencing to brain tissue water signal has been recommended as this method accounts for RF inhomogeneities and coil loading, which present difficulties when using external reference methods. In this study two methods for deriving the brain tissue water signal are compared: an interleaved MRSI-resolution water reference co-acquired with MRSI data and a high-resolution, quantitative water content mapping. The results show while both normalization methods detected altered metabolites, in agreement with the clinical findings, the water-mapping normalization method provided higher sensitivity for differentiating TBI versus control groups.

1435.   Multi-Echo based Correlated Spectroscopic Imaging 
Jon Furuyama1, and M. Albert Thomas1
1UCLA, Los Angeles, CA, United States

Despite the clinical potential for Chemical Shift Imaging (CSI), its widespread applicability is limited by the severe spectral overlap in the one-dimensional spectra. Two-dimensional Magnetic Resonance Spectroscopy (2D MRS) has been proposed to alleviate complications due to spectral overlap, but suffers due to limited coverage. We propose the use of spin echoes to accelerate the already established Echo-Planar Correlated Spectroscopic Imaging (EPCOSI) technique. We show that the Multi-Echo based Echo Planar Correlated Spectroscopic Imaging (ME-EPCOSI) technique produces comparable 2D MRS spectra to the EPCOSI technique but in half the scan time without significant artifacts.

1436.   Spatiotemporal Denoising of MR Spectroscopic Imaging Data by Low-rank Approximations 
Hien Nguyen1, Xi Peng2,3, Minh Do4, and Zhi-Pei Liang4
1Department of Electrical & Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 2School of Electronic Information, Wuhan University, China, People's Republic of, 3Department of Electrical & Computer Engineering, University of Illinois at Urbana-Champaign, United States, 4Department of Electrical & Computer Engineering, University of Illinoist at Urbana-Champaign, United States

A new scheme is proposed to denoise magnetic resonance spectroscopic imaging (MRSI) data by exploiting two low-rank structures that exist in MRSI data: one due to partial separability and the other is due to linear predictability. Experimental results demonstrate that the proposed method is effective in denoising MRSI data while preserving spatial-spectral features in a wide range of SNR values.

1437.   Non-linear Concentration Effects in Magnetic Particle Imaging 
Volker Christian Behr1, Thomas Kampf1, Jan-Philip Gehrcke1, Martin Andreas Rückert1,2, Patrick Vogel1,2, Walter H. Kullmann2, and Peter Michael Jakob1,3
1Experimental Physics 5, University of Würzburg, Würzburg, Germany, 2Medical Engineering, University of Applied Sciences Würzburg-Schweinfurt, Schweinfurt, Germany, 3Magnetic Resonance Bavaria e.V., Würzburg, Germany

In magnetic particle imaging (MPI), Langevin’s single particle model (SPM) yields a linear relation between magnetic particle concentration c and higher harmonic amplitudes. In reality, the MPI signal is, due to dipolar interactions, non-linearly related to c. Using a second order modified mean field theory for a more adequate modeling of the system simulations were performed to examine deviations from the prediction by the SPM. The results of these simulations are validated by experiments on the concentration dependence. Ignoring the impact of higher concentrations on the MPI signal may lead to severe errors in the interpretation of measured data.

1438.   Encoding of pre-selected compartments produces large SNR and speed advantages for 31P MRS 
Yi Zhang1,2, Refaat E. Gabr1, Michael Schär1,3, Robert G. Weiss1,4, and Paul A. Bottomley1,2
1Division of MR Research, Johns Hopkins Univesity, Baltimore, Maryland, United States, 2ECE, Johns Hopkins University, Baltimore, Maryland, United States, 3Philips Healthcare, Cleveland, Ohio, United States, 4Division of Cardiology, Johns Hopkins Univesity, Baltimore, Maryland, United States

Scan-time and signal-to-noise ratio (SNR) are central problems for MRS of low-concentration metabolites. Matching voxel sizes to anatomical compartments a priori, yields better SNR than adding signals from smaller chemical shift imaging (CSI) voxels post-acquisition to create an average spectrum from the same volume. While several solutions were proposed for CSI, the necessary a priori compartmentation and tailoring of gradient-encoding was never really implemented in humans. Here, we use linear algebraic modeling and a reduced phase-encoding set to achieve manyfold gains in SNR and/or scan-time reduction for 31P MRS in the human leg and heart vs. the conventional CSI experiment.

Traditional Posters : Other
Click on to view the abstract pdf and click on to view the pdf of the poster viewable in the poster hall.
Spectroscopy - Other

Wednesday May 11th
Exhibition Hall  13:30 - 15:30

1439.   T2 Relaxation Times in the Human Brain at 7 T 
Malgorzata Marjanska1, Edward J Auerbach1, Romain Valabregue2, Pierre-Francois Van de Moortele1, Gregor Adriany1, and Michael Garwood1
1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 2Hôpital Pitié-Salpêtrière, Paris, France

To obtain absolute concentrations of metabolites from spectra obtained at longer echo times, the knowledge of both the J-modulation and T2 relaxation times is required. The T2 relaxation times at 7 T have been reported previously for the methyl protons of N-acetylaspartate (NAA) and the methyl protons of total creatine (creatine + phosphocreatine, tCr). The aim of this study was to measure T2 relaxation times in different brain regions of the singlets and J-coupled metabolites.

1440.   Precision evolution of the neuroglial metabolic fluxes with the experimental conditions, when using two-compartment modeling applied to [2-13C] acetate dynamic MRS studies 
Bernard Lanz1, Lijing Xin1, and Rolf Gruetter1,2
1Laboratory for Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 2Department of Radiology, Universities of Lausanne and Geneva, Lausanne and Geneva, Switzerland

[2-13C]acetate infusion coupled with 13C MRS enables the separate assessment of glial and neuronal Krebs cycle fluxes and the determination of the apparent neurotransmission flux with higher accuracy than 13C labeled glucose, due to the glial specificity of acetate metabolism. Furthermore, these fluxes are determined with different precisions, which might strongly depend on the experimental conditions. In this study, we analyze the effect of the experiment duration, the time resolution and the noise level of the data on the standard deviation of the neuroglial fluxes, determined with Monte-Carlo simulation.

1441.   In Vivo Detection of 13C Isotopomer Turnover in the Human Brain 
Shizhe S Li1, Yan Zhang1, Maria Ferraris Araneta1, Christopher Johnson1, Yun Xiang1, Robert B Innis1, and Jun Shen1
1National Institutes of Health, Bethesda, Maryland, United States

Previously 13C isotopomers were observed in the human brain in the aliphatic spectral region using [1-13C]glucoseinfusion and long signal averaging time. Carboxylic/amide carbons can only form singlets and doublets even when uniformly labeled substrates are used, resulting in spectral simplification. To investigate the feasibility of simultaneously detecting two different isotopomers on the same carbon in the carboxylic/amide region in the human brain, we infused [U-13C]glucose and [2-13C]glucose because [U-13C]glucose produces doublets in the carboxylic/amide region while [2-13C]glucose only produces singlets. Dynamic turnover of these isotopomers were detected for the first time in the human brain.

1442.   In vivo L-COSY MRS of Healthy Brain and Glioblastoma 
Saadallah Ramadan1, Ovidiu C Andronesi2, Peter Stanwell1, Alexander Lin1, Gregory A Sorensen2, and Carolyn Mountford1
1Radiology, Brigham and Women's Hospital, Boston, MA, United States, 2Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, United States

Acquisition and post processing parameters have been developed to allow, at 3T with a 32 channel head coil, an L-COSY to be acquired from the brain in 11 minutes. Cross peak assignments and relative ratios of metabolites in the healthy brain were recorded and statistically significant differences were recorded between healthy brain and glioblastoma. Good spectral resolution of the in vivo L-COSY allowed comparison with COSY from cultured cell lines.

1443.   Physiological brain temperature change is detectable by MRS 
Yoshichika Yoshioka1,2, Hiroshi Oikawa3, Yoshiyuki Kanbara4, Yutaka Matsumura4, Takashi Inoue5, Tsuyoshi Matsuda6, Akira Nabetani6, and Junji Seki7
1Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan, 2CREST, JST, Kawaguchi, Saitama, Japan, 3Radiology, Ninohe Haspital, Iwate, Japan, 4High Field MRI Research Institute, Iwate Medical University, Iwate, Japan, 5Neurosurgery, Kohnan Hospital, Sendai, Japan, 6GE Healthcare Japan Corp., Tokyo, Japan, 7National Cerebral and Cardiovascular Center Research Institute, Suita, Japan

We could detect the dynamic change of human brain temperature noninvasively using 1H-NMR spectroscopy. Our results show that the human brain temperature changes dynamically even at physiological conditions and by physiological tasks. Moreover the temperature change of human brain was larger than that of esophagus and axilla. This indicates that the brain temperature is affected easily by the blood flowing into the brain and also that the temperature of this blood is easily affected by foods and drinks. We can easily change the brain temperature of about 0.5 oC by drinking or light exercise.

1444.   2D Diffusion Weighted Chemical Shift Imaging of Brain Metabolites at 7T 
Aranee Techawiboonwong1, Hermien Kan2, Maarten Versluis2, Andrew Webb2, and Itamar Ronen2
1Electrical Engineering, Mahidol University, Puttamonton, Nakornpathom, Thailand, 2C.J. Gorter Center for High Field MRI, Radiology, Leiden University Medical Center, Netherlands

Diffusion-weighted spectroscopy of brain metabolites provides microstructural information specific to compartmental geometry in which they reside. So far, all DWS studies have been performed as single volume scans where accurate calculations of metabolite diffusion properties requires proper phasing of individual spectra prior to averaging to avoid destructive signal summation. Here, we present for the first time a complete 2D-DW-CSI experiment of human brain metabolites which yield sensible maps of their diffusion properties. The technique’s reliability is crucially enhanced using a navigator, which helps remove severe phase fluctuations induced by the diffusion gradients and correctly evaluate metabolite diffusion properties.

1445.   Single Voxel MR Spectroscopy Data Quality and Metabolite Signature of the Isolated Amygdala 
Lisa Angelos1, Brendon M Nacewicz1, Andrew L Alexander1,2, and Richard J Davidson1,3
1Waisman Brain Imaging Laboratory, University of Wisconsin -- Madison, Madison, WI, United States, 2Department of Medical Physics, University of Wisconsin -- Madison, Madison, WI, United States, 3Department of Psychology, University of Wisconsin -- Madison, Madison, WI, United States

We have developed a single-voxel amygdala spectroscopy protocol that maximizes voxel volume by adapting the prescription to each individual’s anatomy, and minimizes contamination and artifacts from surrounding tissue, especially hippocampus, with outer volume saturation bands. Compared to an occipital cortex voxel with similar data quality, amygdala NAA was 34% lower and Cho was 2.6 times higher, while Cre concentrations were similar. Amygdala NAA/(Cre+Cho) was higher than results from the hippocampus literature, suggesting an amygdala partial volume contribution to metabolite gradients observed in CSI measurements of the hippocampus.

1446.   Define impact of fasting on human brain acid-base homeostasis using natural abundance 13C and 31P MRS 
Napapon Sailasuta1, Kent C Harris1, Thao Tran1, and Brian D Ross1
1Magnetic Resonance Spectroscopy Unit, Huntington Medical Research Institute, Pasadena, California, United States

Natural abundance 13C MRS and proton decoupled 31P MRS were utilized to explore the impact of fasting on Intracerebral pH and acid-base homeostasis. There were no findings of altered pH when a significant reduction of HCO3 was found. This unexpected finding suggests unknown factors may be at play and relevant for outcome predictions in bicarbonate replacement therapy.

1447.   Changes in foot orientation alters residual dipolar couplings of Creatine and Phosphocreatine in the skeletal muscle of rats 
Nikita Agarwal1, Loyola D'Silva1, and Sambasivam S Velan1
1Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, Singapore, Singapore, Singapore

In this work we have analyzed the residual dipolar couplings on Creatine (Cr) and Phosphocreatine (PCr) in the skeletal muscle spectra of the Tibialis Anterior muscle compartment in rats. The chemical shift separation of Cr, PCr, Taurine and carnitine is dependent on the foot angle which alters the orientation of the muscle fibers with respect to the main magnetic field. We have also measured the separation of Cr and PCr by changing the angle of the foot with respect to the main magnetic field.

1448.   Multi Task Bayesian Compressed Sensing in Sparse 2D Spectroscopy 
Trina Kok1, Berkin Bilgic1, and Elfar Adalsteinsson1,2
1Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States, 2Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, United States

This work is an investigation of the application of compressed sensing reconstruction methods to 2D spectroscopy methods, specifically CTPRESS. The investigated reconstructed methods are conjugate gradient, single bayesian reconstruction and joint bayesian reconstruction.

1449.   Bringing Quantitative Clinical Routine MR-Spectroscopy and Clinical MR-Image Viewing Together: Novel jMRUI plug-ins for DICOM-Network File Transfer DICOM Image Stack Analysis 
Johannes Slotboom1, Dirk van Ormondt2, Danielle Graveron-Demilly3, Dan Stefan4, Caspar Brekenfeld1, Roland Wiest1, Gerhard Schroth1, and Olivier Scheidegger1
1DRNN-DIN/SCAN, University Hospital Berne, Berne, Switzerland, 2Applied Physics, Delft University of Technology, Delft, Netherlands, 3Laboratoire Creatis-LRMN, Université Claude Bernard LYON 1, Lyon, France, 4Alter Systems

Most advanced applications for quantitative MRS can poorly be integrated in clinical routine workflow. The reasons are: (1.) they have very rudimentary image display/analysis possibilities; (2.) they have no DICOM-network capabilities for receiving/sending spectroscopy/image report files using the DICOM network protocol (data must manually be exported to off-line files (time consuming)), and (3.) they are file oriented, i.e. the user has to open files. Clinical users however do not work file-oriented, but patient/study/series-oriented. This paper reports on developed plug-ins for jMRUI to make quantitative MRS attractive for clinical routine-use.

1450.   Highly resolved 2D ISIS CT-PRESS in human brain using enhanced window for shifted echoes 
Hidehiro Watanabe1, Nobuhiro Takaya1, and Fumiyuki Mitsumori1
1Environmental Chemistry Division, National Institute for Environmental Studies, Tsukuba, Ibaraki, Japan

Shifted echo center causes overlapped tilted peaks in the 2D CT-PRESS spectra. To achieve highly resolved 2D CT-PRESS spectra in human brain, a resolution enhancement window function was proposed. This window function consists of an enhancement part for shifting echoes and a conventional window part, such as Lorentzian, Gaussian or sine-bell. 2D CT-PRESS spectra were obtained from human brains at 4.7 T. While three peaks of GABA C2H (2.28 ppm), Glu C4H (2.35 ppm) and Gln C4H (2.44 ppm) were overlapped on the spectra applied with the conventional window, these peaks were resolved on the spectra with the enhancement window.

1451.   Improved SNR Efficiency in MR Spectroscopy with the Fast Pade Transform 
Sun Kim1, and Glen Morrell2
1School of Medicine, University of Utah, Salt Lake City, Utah, United States, 2Radiology, University of Utah, Salt Lake City, Utah, United States

The fast Padé transform can be used to create NMR spectra from truncated free induction decay (FID) signals at high spectral resolution that would require long readout times for conventional Fourier transform reconstruction. The capability to create high resolution spectra from short truncated FIDs with the Padé transform enables spectroscopy with short TR, low flip angle, and rapid acquisition, potentially yielding SNR improvements by optimization of SNR efficiency. We investigate the SNR gains that are possible using the fast Padé transform to shorten the required readout time for high resolution spectra, within the parameters of a typical brain spectroscopy experiment.

1452.   Ultrafast high-resolution J-resolved spectroscopy in inhomogeneous fields 
Zhong Chen1, Yulan Lin1, Zhiyong Zhang1, and Shuhui Cai1
1Department of Physics, Fujian Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, Fujian, China, People's Republic of

The 2D NMR J-resolved spectroscopy can effectively simplify the spectra and improve the spectral resolution. In this abstract, a new pulse sequence based on spatially encoded intermolecular zero-quantum coherences (iZQCs) was presented to ultrafast obtain high-resolution NMR spectra in inhomogeneous fields. Eexperimental results indicate that the chemical shift and J-coupling information are well retained in severely inhomogeneous fields.

1453.   Grid-based shimming of single-voxel MRS 
Judd M Storrs1,2, Mohan Jayatilake1,3, Wen-Jang Chu1,2, and Jing-Huei Lee1,4
1Center for Imaging Research, University of Cincinnati, Cincinnati, Ohio, United States, 2Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati, Ohio, United States, 3Department of Physics, University of Cincinnati, Cincinnati, Ohio, United States, 4School of Energy, Environmental, Biological and Medical Engineering, University of Cincinnati, Cincinnati, Ohio, United States

B0 inhomogeneity within a single-voxel MRS volume-of-interest (VOI) is measured using a 3multiplication sign3multiplication sign3 grid of smaller MRS voxels distributed within the VOI. A specific sequence for acqisition of the grid allows repetition time to be halved without decreasing the effective relaxation time of each grid voxel. The acquired spectra is analyzed to produce first- and second-order shim updates to improve B0 homogeneity within the VOI.

1454.   Analysis of Saturated T2 Curves for Rapid Relaxometry Measurements in PRESS Localization 
Jack Knight-Scott1
1Radiology, CHOA, Atlanta, Georgia, United States

The Rapid Relaxometry through Acquisition of Multiple Saturated T2 Curves (RRAMSC) technique is, in theory, limited to STEAM localization, where the recovery period allows specific control of the degree of longitudinal magnetization that recovers. Because PRESS lacks a well-defined recovery period, RRAMSC trade-off between changes in the TE and TR, to keep saturation effects constant, cannot be calculated over a generic range of different T1 values. Here we examine the effects of approximating the recovery when employing RRAMSC with PRESS localization.

Traditional Posters : Other
Click on to view the abstract pdf and click on to view the pdf of the poster viewable in the poster hall.
MRS of Cells, Body Fluids & Others

Thursday May 12th
Exhibition Hall  13:30 - 15:30

1455.   A Novel 5mm NMR-Compatible Micro-Spindle Bioreactor for Steady-State and Dynamic in Cell NMR 
Kayvan R. Keshari1, Mark Van Criekinge2, Daniel Vigneron2, and John Kurhanewicz2
1UCSF, San Francisco, CA, United States, 2UCSF

Current NMR-compatible bioreactor systems have utilized standard 10–25mm designs to study cellular metabolism inside of a magnet. Though these systems are applicable to large volumes of immortalized cells (108 cells), obtaining the required volumes of primary cells and/or tissues is prohibitive. The use of primary cell and tissue cultures provides a more clinically relevant platform for testing new hyperpolarized MR probes and therapies. This preliminary study demonstrates the feasibility of using this 5mm bioreactor design in combination with hyperpolarized MR to explore both in cell steady-state and dynamic metabolism using dramatically reduced cell and perfusate volumes.

1456.   Insight into neural cell metabolism by NMR – employing UDP-GlcNAc as a unique metabolic marker 
Anika Gallinger1, Mailin Doepkens1, Thorsten Biet1, Luc Pellerin2, and Thomas Peters1
1Institute of Chemistry, University of Luebeck, Luebeck, Germany, 2Department of Physiology, University of Lausanne, Lausanne, Switzerland

UDP-N-acetylglucosamine (UDP-GlcNAc) is an activated sugar, produced via the hexosamine biosynthetic pathway (HBP). This activated sugar is the key substrate for O-GlcNAcylation, a dynamic posttranslational modification of nuclear and cytosolic proteins. Changes in flux through the HBP either increase or decrease UDP-GlcNAc levels, affecting the O-GlcNAcylation of many proteins. Aberrant O-GlcNAcylation can be associated with human diseases such as diabetes, Alzheimer’s disease and cancer. Alterations of UDP-GlcNAc levels may provide an indication of the development of metabolic disorders. Therefore, we are currently exploring the potential of UDP-GlcNAc as a NMR detectable metabolic marker in neuronal cells.

1457.   A New Small-Volume MR-Compatible Hollow-Fiber Bioreactor Cell Culture System 
Jean-Philippe Galons1,2, Logan Robinson3, Mike Bower4, Joseph Divijak4, Greg Russell5, and Ted Trouard1,4
1Radiology, University of Arizona, Tucson, AZ, United States, 2Cancer Center, University of Arizona, Tucson, AZ, United States, 3Chemical Engineering, University of Arizona, Tucson, AZ, United States, 4Biomedical Engineering, University of Arizona, Tucson, AZ, United States, 5Physics, University of Arizona, Tucson, AZ, United States

Currently there is no commercially available perfused cell culture bioreactor system that is compatible with conventional NMR/MRI hardware. Taking advantage of new capabilities in 3D polymer printing technology we have generated a new small-volume hollow-fiber bioreactor device that is compatible with conventional vertical-bore MR magnets (top loading) and that fits within commercial 5 mm diameter RF probes. This bioreactor provides an inexpensive new tool for studying cell cultures with MR and utilizes the high sensitivity of commercial 5mm diameter RF hardware to generate high SNR.

1458.   Application of Excitation Sculpting in the Quantification of Conjugated Bile Acids in Bile 
Omkar B Ijare1, Tedros Bezabeh1, Nils Albiin2, Annika Bergquist2, Urban Arnelo2, Matthias Lohr2, and Ian C.P. Smith1
1National Research Council Institute for Biodiagnostics, Winnipeg, Manitoba, Canada, 2Karolinska University Hospital, Karolinska Institutet, Huddinge, Stockholm, Sweden

Bile acids are major components of bile and are present mostly in conjugated forms with glycine and/or taurine. Amide bonds formed as a result of this conjugation provide well resolved ‘NH’ signals in the down-field region of 1H MR spectrum of bile. However, at physiologic pH, these amide protons are in dynamic exchange with biliary water and show decreased signal intensity. Lowering the pH of bile below physiologic value (~ 6.0) has been helpful in recovering such signal loss. In this study, we propose the use of excitation sculpting sequence for the quantification of conjugated bile acids using their ‘NH’ signals without the need for pH adjustment.

1459.   ‘Mycolates and Phenolic glycolipids as biomarker for tubercular ascites’ : A Proton Magnetic Resonance spectroscopic approach 
abhinav arun sonkar1, shatakshi shrivastav2, raghuvendra kumar3, amita jain4, and Raja Roy5
1surgery, csm medical university, lucknow, uttar pradesh, India, 2center for bio magnaetic resonance, SGPGI, Lucknow, Uttar Pradesh, India, 3surgery, CSM Medical University( King Georges Medical University), Lucknow, uttar pradesh, India, 4Microbiology, CSM Medical University, Lucknow, Uttar Pradesh, India, 5Center for Bio magnetic Resonance, SGPGI, Lucknow, Uttar Pradeshi, India

Abdominal TB involves the gastrointestinal tract, peritoneum, lymph node or solid viscera, constituting up to 12% of extra pulmonary TB and 1-3% of the total cases of tuberculosis. The disease involves different site/s within the abdomen with different morphologies, making the signs and symptoms of disease, very non-specific. This results in poor prognosis and diagnosis and opens an avenue for investigative research. In the present study, the ascitic fluid obtained from different groups of patients suffering with TB or other benign diseases were studied by 1H NMR spectroscopy to identify the fingerprint biomarker in tubercular ascitis for its differential diagnosis.

1460.   In vivo high-resolution magic angle spinning proton NMR spectroscopy of Drosophila melanogaster flies as a model system to investigate mitochondrial dysfunction in trauma 
Valeria Righi1,2, Georgios Apidianakis 3, Nikos Psychogios1,2, Laurence G. Rahme3, Ronald G. Tompkins4, and Aria A. Tzika1,2
1Department of Surgery, NMR Surgical Laboratory, MGH and Shriners Burn Institute, Harvard Medical School, Boston, MA, United States, 2Department of Radiology, Athinoula A. Martinos Center of Biomedical Imaging, Boston, MA, United States, 3Department of Surgery, Molecular Surgery Laboratory, MGH and Shriners Burn Institute, Harvard Medical School, Boston, MA, United States,4Department of Surgery, MGH and Shriners Burn Institute, Harvard Medical School, Boston, MA, United States

Using high-resolution magic angle spinning proton NMR spectroscopy in vivo, we evaluated in a Drosophila melanogaster. The main finding of this study was an increase in (CH2)n lipids at 1.33 ppm which is an insulin resistance biomarker in skeletal muscle of Drosophila. We thus provide evidence for the hypothesis that GST2 mutation is linked to insulin signaling. Our approach advances the development of novel in vivo non-destructive research approaches in the model host D. melanogaster, and suggests biomarkers for investigation of biomedical paradigms that may contribute to the development of novel therapeutics.

1461.   Preliminary study on MR spectroscopy measurements for metabolomic change during adipogenic differentiation of human mesenchymal stem cell 
Song I Chun1, Dong Hwa Kim1, Jee Hyun Cho2, Kwan Soo Hong2, Jung Woog Shin1, and Chi Woong Mun1,3
1Biomedical Engineering, Inje University, Gimhae, Korea, Republic of, 2Korea Basic Science Institute, Cheongwon-Gun, Chungcheongbuk-Do, Korea, Republic of, 3First Research Group, Inje University, Korea, Republic of

Stem cells have the unique properties of pluripotency/multipotency and they are able to differentiate into a diverse range of specialized cell types. Unknown materials generated during the differentiation of the stem cells were presumed to be another cell. The purpose of this study is to compare the metabolite changes between the pellet samples and the hydrogelation lysed samples of the human mesenchymal stem cells (hMSC) which are differentiated to adipose using magnetic resonance spectroscopy (MRS) along the passing time. Adipogenic differentiation of hMSCs was processed for 4 cycles using adipogenic induction medium and adipogenic maintenance medium (1cycle: adipogenic induction medium - 3 days + adipogenic maintenance medium - 1 day). The adipogenic differentiation rate of hMSCs was confirmed by Oil Red O staining as shown in Figure 1. Two type samples, one was hydrogelation lysed cell samples prepared by using 2.5% viscosity alginic acid and solubilization solution (55mM sodium citrate, 150mM NaCl). The other was cell pellet washed by D2O saline (99% D2O+0.9% NaCl) and minimized H2O signal. All samples were filled in 5mm NMR tube with external reference, 45.8mM 3-(trimethylsilyl)-1-propanesulfonic acid, sodium salt (DSS, Sigma).14.1T NMR micro-imaging machine (Bruker, Germany) was used to obtain the spectrum from the samples with Point Resolved Spectroscopy (PRESS; volume selected) pulse sequence and zqpr pulse (total volume) sequence.The acquired data were analyzed by the NMR spectrum processing software (TopSpin 2.1, Bruker, Germany) after the phase/baseline correction, peaks picking and integration.The adipose MR peaks were increased at both hydrogelation lysed sample and cell pellet sample. Especially, lipid signals of methyl group (-CH3) and methylene group (-CH2) were noticeably increased. For the samples of lysis cells no signal increment was found except lipids.On the other hand, the other metabolite variations in the cell pellet samples were observed such as isoleucine, alanine, leucine, lysine, methionine, glutamate, glutamine, choline, phosphocholine, myo-inositol and creatine etc. In case of methionine signal, peak 16, it was not observed during 1~3 cycles, but we could find it at 4 cycle when completed adipogenic differentiation.In this study, we confirmed that MR spectral peaks related to various lipid metabolites were increased when hMSCs were differentiated to adipose. During adipogenic differentiation process, authors also observed that lipid and other amino-acids related to energy metabolism were increased from the pellet of the cell samples. On the basis of this results, confirming the cell metabolites in the pellet will be helpful to find the basis standard of in-vivo cell metabolite measurements

Traditional Posters : Other
Click on to view the abstract pdf and click on to view the pdf of the poster viewable in the poster hall.

Monday May 9th
Exhibition Hall  14:00 - 16:00

1462.   Balanced SSFP Imaging using a Biplanar MR Microscope 
Andrey V Demyanenko1, and Julian Michael Tyszka1
1Biology, California Institute of Technology, Pasadena, CA, United States

Balanced steady-state free precession (bSSFP) imaging places high demands on gradient performance in terms of waveform fidelity, maximum slew rate and gradient amplitude. We present here a biplanar gradient coil designed to minimize eddy currents and allow high SNR efficiency bSSFP with repetition times of 2.5ms at isotropic spatial resolutions on the order of 60 microns. This hardware is well-suited to high resolution MR imaging of chemically-fixed tissue samples, including whole early-stage mammalian embryos, whole mouse brains and thick tissue slices.

1463.   Ultra High-Resolution 3D Anatomical MRI of the Ex Vivo Retina at 10x10x14µm 
Bryan H De La Garza1, and Timothy Q Duong1
1Research Imaging Institute, Opthamology/Radiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States

This study explored the use of ultra high-resolution 3D anatomical MRI (MR microscopy) to resolve different layers ex vivo rat retina at a nominal resolution of 10x10x14µm. MR microscopy showed multiple distinct bands with remarkable contrast and in excellent agreement with similar histological sections. MRI and histological layer thicknesses were in excellent agreement.

1464.   Mitigation of Transmit Crosstalk in Multiple-Mouse MRI 
Jonathan Bishop1, Brige Chugh2, R. Mark Henkelman1,2, and John G Sled1,2
1Hospital for Sick Children, Toronto, ON, Canada, 2Medical Biophysics, University of Toronto

Active digital decoupling for reducing transmit cross-talk in multiple-mouse MRI is demonstrated in a water phantom, with reference to ASL applications.

1465.   Non-invasive Monitoring of Alterations in Rabbit Hearts with Aging Using MR Microscopy 
Min-Sig Hwang1,2, Katja E. Odening3, Bum-Rak Choi3, Gideon Koren3, Stephen J. Blackband1,2, and John R. Forder1,4
1McKnight Brain Institute, Gainesville, FL, United States, 2Neuroscience, University of Florida, Gainesville, FL, United States, 3Cardiovascular Research Center, The Rhode Island Hospital, Alpert Medical School of Brown University, Providence, RI, United States, 4Radiology, University of Florida, Gainesville, FL, United States

The cardiac conduction system is subject to alterations with aging. The aim of this study was to investigate non-invasively the morphological changes in aged heart. Structural changes in the myocardium were examined using MR microscopy (MRM) and high angular resolution diffusion microscopy (HARDM). Purkinje fiber networks in the LV cavity of young and old rabbit hearts were compared. Our results demonstrate combined analysis of the two MR modalities (MRM & HARDM) may be a powerful tool to understand and monitor alterations in the cardiac conduction network that occur as a function of age.

1466.   Histological Confirmation of Aplysia californica Neuron Structure Observed Using MR Microscopy 
Choong H Lee1,2, Jeremy Joseph Flint2,3, Michael Fey4, Franck Vincent4, and Stephen Blackband2,5
1Electrical Engineering, University of Florida, Gainesville, Fl, United States, 2McKnight Brain Institute, Gainesville, Fl, United States, 3Neuroscience, University of Florida, Gainesville, Fl, United States, 4Bruker Biospin, 5National High Magnetic Field Laboratory, Tallahassee, Fl, United States

Although MR microscopy has visualized single cells, verification of the assignment of cellular compartments has not been performed in Aplysia californica neurons. Using a variety of stains, new microcoils, thin slices of fixed neurons, and the highest resolution MRM on Aplysia neurons reported to date, the assignment of the cytoplasmic and nuclear compartments and the plasma membrane is verified. Also, when collagenase is not used, many small cells are observed on the large neuron. These results impact future modeling approaches of MR signals in tissues.

1467.   Magnetic microparticle size optimization for susceptibility contrast imaging 
Nina Olamaei1, Frederick Gosselin2, Farida Cheriet2, and Sylvain Martel2
1École Polytechnique Montréal, Montreal, QC, Canada, 2École Polytechnique Montréal

The effective intravoxel dephasing makes the magnetic microparticles promising candidate for MR imaging. In the present work, the behavior of the susceptibility artifact is investigated as microparticles are broken to smaller particles using a numerical simulation. The diameters of the particles were varied while keeping the total volume of magnetic materials constant. The signal loss was calculated for different combinations of particle sizes and TEs. The results suggest that the distribution of smaller particles over a surface creates a more pronounced signal loss compared to that created by larger particles on an identical total volume.

1468.   In-utero imaging of the early mouse embryo 
Prodromos Parasoglou1,2, Cesar A Berrios-Otero1,2, Brian J Nieman3, and Daniel H Turnbull1,2
1Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, New York, United States, 2Department of Radiology, New York University School of Medicine, New York, New York, United States, 3Mouse Imaging Centre, The Hospital for Sick Children, Toronto, Ontario, Canada

In this work we report the acquisition of high-resolution 3D images of the vasculature of embryos starting at embryonic day E10.5, without the use of a contrast agent. Mouse embryos were imaged in-utero between E10.5 and E17.5. To our knowledge this is the first time high resolution 3D images have been acquired at this early stage, showing the exciting possibility of performing longitudinal studies of embryonic development at stages close to the onset of neurogenesis and embryonic cardiac activity.

Traditional Posters : Other
Click on to view the abstract pdf and click on to view the pdf of the poster viewable in the poster hall.

Tuesday May 10th
Exhibition Hall  13:30 - 15:30

1469.   Detection of Blood-brain barrier disruption in a mouse model of transient cerebral ischemia by EPR imaging 
Hirotada G Fujii1, Katsuya Kawanishi2, Hideo Sato-Akaba3, Miho Emoto1, and Hiroshi Hirata4
1Center for Medical Education, Sapporo Medical Univeristy, Sapporo, Hokkaido, Japan, 2Health Sciences University of Hokkaido, Japan, 3Osaka University, Japan, 4Hokkaido University, Japan

In vivo EPR imaging provides a powerful method for the evaluation and visualization of oxidative stress, non-invasively. The purpose of this study was to examine the effect of oxidative stress on an ischemia-reperfusion (IR) model mouse brain with an improved EPR imaging system, capable of rapid field scanning. The results obtained in this study clearly show that through the use of blood-brain barrier (BBB)-permeable and BBB-impermeable nitroxide, improved EPR imaging can be used to asses BBB permeability in the wounded hemisphere of IR model mice. With three-dimensional surface-rendered images, the infarcted hemisphere of IR model mice can be visualized.

1470.   Simultaneous CW-EPR imaging of isotopic nitroxyl radicals 
Anna Pawlak1, Ryohei Ito1, Hirotada Fujii2, and Hiroshi Hirata1
1Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Hokkaido, Japan, 2Center for Medical Education, Sapporo Medical University, Sapporo, Hokkaido, Japan

The major advancement outlined in this study is the simultaneous visualization of two kinds of nitroxyl radicals using electron paramagnetic resonance (EPR) spectroscopy and imaging. We demonstrated the simultaneous imaging of 14N-labeled and 15N-labeled nitroxyl radicals with a 750-MHz CW-EPR imager. By using the characteristics of hyperfine structure of nitroxyl radicals, the distribution of isotopic nitroxyl radicals could be visualized simulaneously. We show the proof-of-concept experiments for simultaneous EPR imaging.

1471.   EPR-based pH mapping with a method of partially scanned spectral-spatial imaging 
Shunichi Koda1, Jonathan Goodwin1, Valery Khramtsov2, Hirotada Fujii3, and Hiroshi Hirata1
1Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Hokkaido, Japan, 2Davis Heart and Lung Research Institute and the Division of Cardiovascular Medicine, The Ohio State University, Columbus, Ohio, United States, 3Center for Medical Education, Sapporo Medical University, Sapporo, Hokkaido, Japan

We demonstrated a newly developed method of pH mapping based on electron paramagnetic resonance (EPR). To reduce the missing-angle and the field-of-view of spectral-spatial images, EPR spectra at lower and center components of pH-sensitive nitroxyl radicals were individually measured. Reasonable pH values for test tubes were obtained with our pH mapping method. In this study, we obtained pH values with low standard deviation (}0.05 pH).

1472.   Effects of a novel mitochondrial peptide on redox status as measured by EPR in Drosophila melanogaster post-trauma 
Nikolaos Psychogios1, Harold M Swartz2, Hazel Szeto3, Ronald G Tompkins4, Nadeem Khan2, and Aria A Tzika1,4
1NMR Surgical Laboratory, Department of Surgery, Massachusetts General Hospital and Shriners Burn Institute, Harvard Medical School, Boston, MA, United States, 2EPR Center for Viable Systems, Department of Diagnostic Radiology, Dartmouth Medical School, Hanover, NH, United States, 3Department of Pharmacology, Joan and Sanford I. Weill Medical College of Cornell University, Joan and Sanford I. Weill Medical College of Cornell University, New York, NY, United States, 4Department of Surgery, Massachusetts General Hospital and Shriners Burn Institute, Harvard Medical School, Boston, MA, United States

Using in vivo electron paramagnetic spectroscopy (EPR), we evaluated in a Drosophila melanogaster fly trauma model the effects of a novel (Szeto-Schiller) SS-31 peptide that targets mammalian mitochondria. From the decay kinetics of nitroxide we measured the mitochondrial redox status of the flies, which increased in injured vs. control aged flies and was indicative of mitochondrial uncoupling. Injection of SS-31 in injured flies normalized the decay rate and recovered the redox status as compared to controls. Our approach in the model host Drosophila melanogaster suggests biomarkers for investigation of biomedical paradigms that may contribute to the development of novel therapeutics.

1473.   Characterization of human melanomas by EPR Imaging 
Quentin Godechal1, Philippe Leveque1, Liliane Marot2, Jean-Francois Baurain2, and Bernard Gallez1
1Louvain Drug Research Institute, Biomedical Magnetic Resonance Research Group, University of Louvain, Brussels, Belgium, 2Cliniques Universitaires Saint Luc, Brussels, Belgium

In this work, we used for the first time EPR imaging as a tool to detect and localize melanin pigments inside human melanoma. The results are very encouraging as we showed that EPR imaging might be able to provide an accurate image of samples and thus allow the determination of the Breslow index (thickness of the lesion) and Clark index (penetration of the tumor), two crucial characteristics for the diagnosis of melanoma.