Traditional Poster Session - MRS, non-H1 & ESR
  MR: Non Proton 1696-1712
  MRS Methodology of Spectroscopic Localization & Imaging 1713-1734
  MRS Quantification 1735-1759
  MRS: Metabolism in Health & Disease 1760-1793
  MRS of Neurological Diseases 1794-1816
  MRS of Normal & Aging Brain 1817-1827

MR: Non Proton
Click on to view the abstract pdf. Click on to view the poster (Not all posters are available for viewing.)
Tuesday 8 May 2012
Exhibition Hall  13:30 - 15:30

1696.   2D Radial Sodium Heart MRI: Prospective vs. Retrospective ECG-Gating using Golden Angle Increments
Simon Konstandin1, and Lothar R. Schad1
1Computer Assisted Clinical Medicine, Heidelberg University, Mannheim, Germany

Sodium heart imaging is mainly used for research on myocardial infarction and viability purposes. The necessity of ECG-triggering for low resolutions was never examined. In this work, the reasonability of ECG-triggering is investigated at low resolutions needed for sodium MRI. Signal errors due to motion artifacts are below 5 % in myocardium and, therefore, the benefit of ECG-triggering is questionable. However, studies on patients with myocardial infarction (i.e., increased signal in the myocardium) must be performed to show the reasonability of ECG-triggering. Retrospective ECG-gating with Golden angle increments is shown for a time-efficient acquisition and, therefore, to increase signal-to-noise ratio.

1697.   2D Radial Sodium MRI using VERSE
Simon Konstandin1, and Lothar R. Schad1
1Computer Assisted Clinical Medicine, Heidelberg University, Mannheim, Germany

Minimal echo times are required for sodium MRI with a fast biexponential transversal decay. The RF pulse duration of slice-selective excitation is limited by gradient slew rate, amplitude, and RF peak power. The minimal necessary RF pulse duration was investigated, depending on flip angle and reference voltage of the coil using different VERSE approaches and Fermi-shaped RF pulses. Sodium heart measurements are shown to demonstrate SNR changes in myocardium due to different minimal echo times.

1698.   A Sodium Phased Array Breast Coil with Hydrogen Transceive
Joshua D Kaggie1,2, John R Campbell3, James Badal3, Rock Hadley2, Daniel J Park3, Glen Morrell2, Dennis Parker2, Rexford D Newbould4, and Neal Bangerter2,3
1Physics, University of Utah, Salt Lake City, UT, United States, 2Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, UT, United States, 3Electrical and Computer Engineering, Brigham Young University, Provo, UT, United States, 4GSK Clinical Imaging Centre, London, United Kingdom

It is commonly accepted that phased array receive coils will improve SNR for 1H-MRI on typical clinical magnets (1.5T or 3T). This work presents a 5-channel 23Na/single-channel 1H coil configuration for 23Na-MRI of the breast at 3T, and demonstrates significant improvements in 23Na SNR in the breast with a 23Na phased-array when compared to a single 23Na loop.

1699.   Chlorine (35Cl) Magnetic Resonance Imaging of the Human Brain and Muscle
Armin M. Nagel1, Florian M. Meise1, Marc-André Weber2,3, Karin Jurkat-Rott4, Frank Lehmann-Horn4, Michael Bock1, Wolfhard Semmler1, and Reiner Umathum1
1Dept. of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 2University Hospital of Heidelberg, Heidelberg, Germany, 3Dept. of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 4Division of Neurophysiology, Ulm University, Ulm, Germany

Chlorine (Cl-) is the most important anion in the human body and is involved in many physiological processes. In this work, for the first time 35Cl-images of the human brain and the skeletal muscle were acquired on a whole body 7 T MRI system. 35Cl exhibits short relaxation times of T2f* = 1.1 ms and T2s* = 6.2 ms in brain parenchyma and T2f* = 0.3 – 0.8 ms and T2s* = 2.5 – 4.5 ms in skeletal muscle. Spatial resolutions of (6 mm)3 (brain) and (11 mm)3 (muscle) could be achieved at an SNR of 15 (brain parenchyma) and 7-15 (muscle).

1700.   Quantitative mapping of the Cl-/Na+ concentration ratio using a double resonant surface coil
Sebastian Baier1, Stefan Kirsch1, Friedrich Wetterling1, Laurent Tritschler2, Patrick Heiler1, and Lothar R Schad1
1Computer Assisted Clinical Medicine, Heidelberg University, Mannheim, Germany, 2Department of Neurology, Heidelberg University, Mannheim, Germany

Here we present a method which enables non-invasive determination of the Cl-/Na+ concentration ratio by means of MRI. The method employs a double resonant 35Cl-23Na surface coil which uses the same tunable loop element for measuring the 35Cl and 23Na signal. Since our sample dimensions are much smaller than lower case Greek lambda/10, the 35Cl and the 23Na image exhibit approximately the same B1 profile. Using a reference with known Cl-/Na+ concentration enables calculation of a concentration ratio map by simply dividing the35Cl image by the 23Na image.

1701.   Assessment of In-Vivo Cartilage Sodium using Soft Inversion Recovery Fluid Suppression
Rebecca E Feldman1, and Christian Beaulieu1
1Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada

Although sodium MRI is a promising technique for assessing knee cartilage health, the presence of fluid in the joint can confound the evaluation of cartilage. Fluid suppression can isolate cartilage signal, but a hard inversion pulse will drastically attenuate the SNR in the image, and make the received signal highly T1 dependant. This abstract shows that a long inversion pulse can improve signal intensity values in fluid suppressed sodium images. The soft inversion sequence produce better in-vivo cartilage SNR than a hard inversion sequence (SNR = 21 vs. 12) acquired in a similar time frame (~10 min).

1702.   Evaluation of cerebrospinal fluid suppression techniques in sodium MRI at 3T
Bhavana Shantilal Solanky1, Frank Riemer1, Claudia A. M. Wheeler-Kingshott1, and Xavier Golay2
1NMR Research Unit, Department of Neuroinflammation, UCL Institute of Neurology, London, United Kingdom, 2Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, United Kingdom

Partial volume effects and the high intensity of the CSF signal may lead to inaccuracies in the determination of 23Na concentrations in peri-ventricular regions (Peri-V). With this in mind we tested two methods of suppressing the CSF signal to enable a more accurate quantification of total 23Na in Peri-V tissue: An inversion recovery (IR) sequence to eliminate CSF based on exploiting T1 relaxation differences between CSF and tissue a dual echo sequence exploiting the difference in T2 relaxation. These methods were compared in terms of residual CSF signal and the resultant effect of CSF contamination in Peri-V regions was assessed

1703.   Characterization of ECM Embedded Biomimetic Scaffolds for Cartilage Tissue Engineering using Sodium Triple-Quantum-Coherence Spectroscopy
Mrignayani Kotecha1, Sriram Ravindran2, Aishwarya Vaidyanathan1, Anne George2, and Richard Magin1
1Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, United States, 2Department of Oral Biology, University of Illinois at Chicago, Chicago, Illinois, United States

Biomimetic scaffolds have been shown to be effective for bone regeneration and similar strategies are under active investigation for cartilage tissue regeneration. The principal components for cartilage tissue regeneration are proteoglycans and collagen, II. We have investigated application of triple quantum sodium spectroscopy for characterization of biomimetic scaffolds for cartilage tissue regeneration. We found that the motional parameter lower case Greek omega0lower case Greek tauc increases during the first two weeks and then suddenly drops before increasing again towards the end of fourth week. This is assumed to be an indicator of proteoglycans production during the early growth stage and random collagen network during the later stage of the growth.

1704.   T1 relaxation times of 31P metabolites in human liver at 7T
Marek Chmelik1, Ivica Just Kukurova1,2, Stephan Gruber1, Martin Krššák3, Michal Povazan1,4, Martin Tkacov1,4, Ladislav Valkovic1, Siegfried Trattnig1, and Wolfgang Bogner1
1MR Centre of Excellence, Dept. Radiology, Medical University of Vienna, Vienna, Austria, 2Department of NMR and MS, Institute of Analytical Chemistry, Slovak University of Technology, Bratislava, Austria, 3Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria, 4Department of Nuclear Physics and Biophysics, Faculty of Mathematics, Physics and Informatics, Commenius University, Bratislava, Slovakia

The purpose of this study was to measure T1 relaxation times of hepatic 31P metabolites at 7T, which are necessary for further method optimizations and corrections during data quantifications. T1 values of eight hepatic 31P metabolite resonances could be determined in our study. No significant differences in T1 were observed for hepatic 31P metabolites at 7 T compared to lower field strength (i.e. 2T and 3T). This absence of any significant changes in T1 with increasing B0 is consistent with previous observations in rat liver, where nearly identical T1 relaxation times were reported for 4.7 T and 8.5 T.

1705.   Comparison between 31P MRS and 18F-FDG PET for response prediction in non-Hodgkin’s lymphoma
Mihaela Rata1, Nandita Desouza1, Michael Germuska1, Michael Partridge2, Martin O Leach1, and Geoffrey S Payne1
1MRI Unit, CR-UK and EPSRC Cancer Imaging Centre, Institute of Cancer Research and Royal Marsden Hospital, Sutton, United Kingdom, 2Radiotherapy and Imaging, CR-UK and EPSRC Cancer Imaging Centre, Institute of Cancer Research and Royal Marsden Hospital, Sutton, United Kingdom

18FDG PET uptake represents the gold standard technique for staging aggressive non-Hodgkin’s lymphomas (NHL) but quantified SUVmax at outset is also predictive of treatment response. The phosphomonester peak normalized by the total amount of â-NTP (nucleoside triphosphates) on 31P-MRS has also demonstrated promise as a predictive biomarker: This study explores the relationship between the predictive biomarkers. The absence of significant correlation between the glucose uptake using 18FDG-PET and PME/bNTP using 31P MRS suggests that they may contain complementary information on response prediction

1706.   1H/31P Polarization Transfer at 7 and 9.4 Tesla for improved specific detection of phosphomono- and -diesters in human breast and breast tumor models.
Jannie P Wijnen1,2, Lu Jiang1, Wybe J.M. van der Kemp2, Dennis W.J. Klomp2, and Kristine Glunde1
1Johns Hopkins University In Vivo Cellular and Molecular Imaging Center,Russell H. Morgan Department, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States, 2Department of Radiology, University Medical Centre Utrecht, Utrecht, Netherlands

Here we have demonstrated that using polarization transfer (PT) methods such as refocused insensitive nuclei enhanced by polarization transfer (RINEPT) and its adiabatic version (BINEPT) at 7 and 9.4Tesla can improve the 31P magnetic resonance spectroscopy (MRS) detection of phosphomono- and –diesters in human breasts and breast tumor xenograft models in vivo. BINEPT 31P MRS was able to detect partially resolved phosphoethanolamine, phosphocholine, glycerophosphoethanolamine and glyerophosphocholine because it is insensitive to unwanted broad resonances from macromolecules that do not posses H-P J-coupling, without compromising SNR compared to direct 31P MRS.

1707.   In vivo 1H MRS and 31P MRSI in Transgenic Mouse Liver Expressing Creatine Kinase
Min-Hui Cui1,2, Kamaiah Jayalakshmi1,3, Wei Zhang3, Laibin Liu3, Chandan Guha3, and Craig A. Branch1,2
1Gruss Magnetic Resonance Research Center, Albert Einstein College of Medicine, Bronx, New York, United States, 2Radiology, Albert Einstein College of Medicine, Bronx, New York, United States, 3Radiation Oncology, Albert Einstein College of Medicine

31P MRSI and 1H MRS have been applied to measure hepatic phosphagens and creatine or cyclocreatine after they were administrated in CK-transgenic mouse expressing CKBBin liver. Phosphocyclocreatine accumulated much more than phosphocreatine in liver. Creatine and cyclocreatine have been detected for the first time in hepatocytes of CK-Tg mouse by in vivo 1H MRS. Hepatic cyclocreatine signal intensity from 1H MRS was correlated strongly with hepatic phosphocyclocreatine concentration estimated by 31P MRSI. These combined 1H MRS and 31P MRSI techniques may provide a noninvasive method to estimate creatine kinase activity in rodents with CK expressing hepatocytes.

1708.   Four-dimensional spectral spatial pH mapping of mouse tumour using Continuous Wave-Electron Paramagnetic Resonance imaging (CW-EPRI) and pH sensitive imidazoline nitroxide
Jonathan Goodwin1, Shunichi Koda1, Masashi Ohfuchi1, Anna Pawlak1, Hironobu Yasui2, Valery Khramstov3, and Hiroshi Hirata1
1Hokkaido University, Sapporo, Hokkaido, Japan, 2Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan, 3Ohio State University

In this work we assess the viability of pH sensitive imidazoline nitroxide for in-vivo pH mapping of mouse tumour using continuous wave electron paramagnetic resonance imaging (CW-EPR) to perform four dimensional spectral-spatial imaging. Comparison of pH in tumour model mouse leg was found to be reduced compared control mouse leg. Co-registration with 7T MRI demonstrated anatomical distribution of acquired pH map obtained from tumour model mouse. Successful demonstration of the technique in a larger population will allow further exploration of the relationship between pHe in tumour, and how the relationship changes in response to radiotherapy with and without radio-sensitizing drugs.

1709.   Distribution and time course of Blood-Brain Barrier-permeable nitroxides in mouse head by MRI and EPR imaging
Miho C Emoto1, Hideo Sato-Akaba2, Hiroshi Hirata3, and Hirotada G Fujii1
1Center for Medical Education, Sapporo Medical University, Sapporo, Hokkaido, Japan, 2Graduate School of Engineering Science, Osaka University, 3Graduate School of Information Science and Technology, Hokkaido University

EPR imaging using nitroxides is a powerful non-invasive method for visualizing the quantification of redox status caused by free radicals in vivo. 3-hydroxymethyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (HMP) and 3-methoxycarbonyl-2,2,5,5-tetramethyl-pirrolidine-1-yloxy (MCP) are widely used as blood-brain barrier-permeable nitroxide probes. In this study, their distributions in a mouse brain and their time courses to enter the brain were compared using our newly developed EPR imaging system and by MRI. The EPR imaging results revealed that MCP was more concentrated in the brain than HMP and that MCP entered the brain more rapidly than HMP after their administration to mice.

1710.   Spectral editing for in vivo 13C MRS
Yun Xiang1, and Jun Shen2
1Department of Laboratory Medicine, Wuhan Medical and Health Center for Women and Children, Wuhan, Hubei, China, 2NIMH, Bethesda, MD, United States

Acetate is a useful substrate for studying astroglial metabolism. To spectrally separate glutamate C5 (182.0 ppm) and acetate C1 (182.15 ppm) a two-step J editing method was devised. Homonuclear 13C-13C couplings were introduced by infusing [1, 2-13C2]acetate. In vivo and phantom experiments were performed to demonstrate complete spectral separation of glutamate C5 from acetate C1. 13C spectral editing allows for studying acetate transport and metabolism in brain using in vivo 13C MRS of carboxylic/amide carbons without spectral interference.

1711.   Hyper-CEST signatures of functionalized 129Xe for sensing biomembrane composition
Leif Schröder1, Jagoda Sloniec2, Christopher Witte1, Ute Resch-Genger2, and Andreas Hennig2
1Leibniz-Institut für Molekulare Pharmakologie (FMP), Berlin, Germany, 2Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany

Hyperpolarized xenon is a powerful NMR probe with both high sensitivity and specificity. It has been applied recently to reveal different intracellular NMR signatures of various cell lines. Here, we present a complementary method to detect different NMR signatures of functionalized xenon that partitions into membranes with negligible translocation. Exposing such sensors to various well defined biomembrane models yield very different z-spectra acquired with the Hyper-CEST method. This approach is sensitive to xenon exchange dynamics reflected by the CEST response. It therefore provides access to the related differences in membrane fluidity and could be used to reveal cell identity.

1712.   Relaxation with Diffusion near Magnetic Particles and Cells: Analytical Description and Experiment
James A. Rioux1,2, Chris V. Bowen2,3, and Valerij G. Kiselev4
1Department of Physics, Dalhousie University, Halifax, Nova Scotia, Canada, 2Institute for Biodiagnostics (Atlantic), National Research Council, Halifax, Nova Scotia, Canada,3Departments of Physics, Radiology and Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada, 4Department of Radiology and Medical Physics, University Medical Center Freiburg, Freiburg, Germany

Existing analytical models of the MRI signal response to spherical magnetic particles (including SPIO-labelled cells) describe the FID and the signal at the echo time TE of spin echo sequences. In this work, we present an extension of these models that also describes the complete signal evolution during the spin echo in regimes where diffusion cannot be neglected. This model shows good agreement with both experimental data and Monte Carlo simulations. Fitting experimental data to this model may allow extraction of additional physical parameters, providing improved quantification of labelled cells.
Traditional Poster Session - MRS, non-H1 & ESR

MRS Methodology of Spectroscopic Localization & Imaging
Click on to view the abstract pdf. Click on to view the poster (Not all posters are available for viewing.)
Tuesday 8 May 2012
Exhibition Hall  13:30 - 15:30

1713.   Phased Array Combination of Maximum-Echo Sampled 2D JPRESS Using Unsupressed Water Signal
Navin Michael1, Suresh Anand Sadananthan2, Lei Zhongding3, Yevgen Marchenko1, and S. Sendhil Velan1
1Singapore Bioimaging Consortium, Biomedical Sciences Institutes, 11 Biopolis Way, Singapore, 2Singapore Institute for Clinical Sciences, 3Institute for Infoccomm Research, Singapore

2D pulse sequences like 2D JPRESS suffer from long acquisition times and can benefit from the acquisition acceleration provided by phase array coils. Prior time-domain signal combination techniques have focused on aligning the initial phase of the multichannel FID to an arbitrary reference. The first time point samples are prone to phase errors. The current work shows that eddy current correction in a maximum echo-sampled 2D JPRESS sequence, using the unsuppressed water signal, implicitly compensates the phase offsets in a phased array coil. This can be used for coherently combining the phased array signals in the time domain.

J-refocused 1H PRESS combined with DEPT for localized saturated fatty acids detection by in vivo 13C MRS
Xing Chen1, Peter Boesiger1, and Anke Henning1
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Zurich, Switzerland

Localized natural abundance 13C MRS provides an investigative tool for studying metabolism. Polarization transfer methods like DEPT can be used to enhance sensitivity. The combination of DEPT with proton localized PRESS avoids the large chemical shift displacement and enables tissue specific investigation of lipid composition. However, the concurrent strong homonuclear proton scalar coupling in many metabolites modifies the proton spin coherence distribution and therefore leads to a substantial reduction in the 13C signal enhancement. In this work, J-refocused PRESS localized DEPT is introduced to suppress this effect and enable simultaneous and tissue specific DEPT enhancement of multiple fatty acid resonances.

1715.   JAM-PRESS: improving the resolution of J-resolved PRESS with editing pulses
Richard AE Edden1,2, Nicolaas AJ Puts1,2, and Peter B Barker1,2
1Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, Baltimore, MD, United States, 2FM Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States

In this abstract, we introduce a new experiment JAM-PRESS that combines the resolution benefits of J-resolved and Mega-edited PRESS measurements. This is achieved by adding editing pulses to alternate TE increments of a J-PRESS experiment. Essentially this modification separates edited and unedited peaks by half the F1 spectral width, improving the resolution of the editing target while retaining J-resolution for other maetabolite peaks. The method is demonstrated in phantom and in vivo as applied to GABA.

1716.   Improved detection of homonuclear coupled spins with constant-time PRESS and broadband refocusing pulses
Martin A. Janich1,2, Rolf F. Schulte2, Steffen J. Glaser1, and Dirk Mayer3,4
1Department of Chemistry, Technische Universität München, Munich, Germany, 2GE Global Research, Munich, Germany, 3Neuroscience Program, SRI International, Menlo Park, CA, United States, 4Department of Radiology, Stanford University, United States

The combination of constant-time point-resolved spectroscopy (CT-PRESS) with optimized broad bandwidth refocusing pulses (S-BURBOP) improved the signal detection of homonuclear coupled spins by reducing the chemical-shift displacement error. The signals of Lactate, Glutamate, and Glutamine were significantly increased in evaluations in a phantom and in healthy volunteers.

1717.   3D Localized 2D J-Resolved MR Spectrum in a single scan
Tangi Roussel1, Patrick Giraudeau2, Hélène Ratiney1, Serge Akoka2, and Sophie Cavassila1
1CREATIS, UMR CNRS 5220, INSERM U1044, Université Claude Bernard Lyon1, University of Lyon, Lyon, Rhône-Alpes, France, 2CEISAM UMR CNRS 6230, Université de Nantes

2D Magnetic Resonance Spectroscopy (MRS) is a well known tool for the analysis of complicated and overlapped MR spectra. However, 2D MRS suffers from long acquisition times due to the necessary collection of numerous increments in the indirect dimension (t1). This paper presents the first 3D localized 2D ultrafast J-resolved MRS sequence, developed on a small animal imaging system, allowing the acquisition of a 3D localized 2D J-resolved MRS spectrum in a single scan. Sensitivity and spatial localization properties were characterized. This sequence offers an efficient signal localization and shows a great potential for in vivo dynamic spectroscopy.

1718.   Distinguishing GABA from lysine in vitro and in vivo by 2D localized correlated spectroscopy
Luke Yuan-Je Wang1,2, Hui Jun Vicky Liao2, Ana K. Cadena2, Saadallah Ramadan3, Carolyn Mountford2,3, and Alexander P. Lin2
1Department of Anesthesiology, Children's Hospital Boston, Boston, MA, United States, 2Department of Radiology, Brigham and Women's Hospital, Boston, MA, United States,3Faculty of Health, The University of Newcastle, Newcastle, New South Wales, Australia

: Lysine and lysine-containing macromolecules have been hypothesized to co-resonate near GABA in 2D COSY. In this proof-of-concept study, we were able to separate the relevant cross-peaks at 3T in vitro and in vivo.

1719.   Reproducibility of glutamate and glutamine quantification in the cingulate cortex using proton echo planar spectroscopic imaging
Woan-Chyi Wang1, Yi-Ru Lin1, David M. Niddam2,3, and Shang-Yueh Tsai4,5
1Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan, 2Brain Research Center, National Yang-Ming University, Taipei, Taiwan, 3Laboratory of Integrated Brain Research, Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan, 4Graduate Institute of Applied Physics, National Chengchi University, Taipei, Taiwan, 5Reasearch Center for Mind, Brain and Learning, National Chengchi University, Taipei, Taiwan

Cingulate cortex (CC) is involved in many pathological conditions including psychiatric disorders and chronic pain. Quantification of Glu and Gln in CC may provide important information about pathological mechanisms and drug dynamics. We used PEPSI sequence with short-TE and TEavg protocols to detect Glu and Gln in CC. Although a better fit was obtained for Glu with TEavg there was no obvious difference in Glu COV between two protocols. In conclusion, PEPSI is suitable for assessment of short-term and long-term changes in brain metabolites. Compared to TEavg, short-TE protocol had similar performance on Glu but provides more accurate quantification of Gln and other metabolites.

1720.   Improvement in lactate signal yield at 3 Tesla using slice-selective broadband refocusing pulses
Mary A McLean1, Martin A Janich2,3, Ralph Noeske4, John R Grififiths1, Steffen J Glaser2, and Rolf F Schulte3
1Cambridge Research Institute, Cancer Research UK, Cambridge, Cambridgeshire, United Kingdom, 2Dept of Chemistry, Technische Universität München, Munich, Germany,3GE Global Research, Munich, Germany, 4Research and Collaboration, GE Healthcare, Berlin, Germany

We examined the effect on lactate yield at 3T of incorporating broadband universal rotation by optimized pulses (BURBOP) into PRESS, in comparison with Shinnar-Le Roux (SLR) refocusing pulses. Lactate yield relative to N-acetyl aspartate in a large uniform phantom was found to be up to 97% of the theoretical maximum when using BURBOP refocusing pulses in conjunction with the ‘overpress’ scheme for further reducing chemical shift misregistration. Without overpress, the yield was 87% for BURBOP pulses vs. 43% for SLR. Lactate signal using BURBOP pulses was also shown to be robust to B1 variation over a range of approximately ±20%.

1721.   RF Coil Selective Adiabatic Excitation in sLASER Sequence for 7T Prostate MRSI at short TE
Catalina S. Arteaga de Castro1, Mariska P. Luttje1, Marco van Vulpen1, Uulke A. van der Heide2, Peter R. Luijten1, and Dennis W.J. Klomp1
1University Medical Center Utrecht, Utrecht, Netherlands, 2Netherlands Cancer Institute, Amsterdam, Netherlands

A non-selective excitation semi-LASER sequence (nsLASER) is presented to use in combination with an endorectal coil (ERC) for prostate MRSI at 7 Tesla. The limited coverage of the ERC makes it possible to use non-localized RF pulses without having spurious artifacts and signals coming from the surrounding structures of the prostate at the cost of a slightly longer acquisition time due to the large FOV needed. Excellent in-vivo MRSI of the prostate is obtained. Even in the presence of water and lipid remaining signals no baseline corruption or artifacts appear. The nsLASER sequence is recommended for prostate MRSI when combined with the use of an ERC at high fields.

1722.   Short TE loalized 1H MR spectroscopy of mouse cervical spinal cord at 11.75T using semi-LASER sequence
Mohamed Tachrount1, Guillaume Duhamel1, Patrick Cozzone1, and Virginie Callot1
1CNRS UMR 6612, Marseille, France

Short TE 1H MR Spectroscopy allows in vivo non-invasive assessment of central nervous system metabolism. It has however not been extensively applied in the spinal cord (SC) due to technical challenges. This work describes an optimized localized 1H MRS for examination of the mice cervical SC at very high magnetic field (11.75 T) using semi-LASER selection sequence. The optimized sequence was successfully validated on healthy mice. This work may open new perspectives to study various pathological conditions such as SC injury.

1723.   A new approach to short-TE full-sensitivity MRSI of human brain at 7T
Lijing Xin1, Vladimir Mlynarik2, and Rolf Gruetter1,2
1Department of Radiology, University of Lausanne, Lausanne, Switzerland, 2Laboratory of functional and metabolic imaging, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland

In this study, a short-TE MRSI sequence (TE=12ms) based on a semi-adiabatic spin-echo was implemented at 7T Siemens scanner, and we demonstrate that it is feasible to measure high quality spectra from multiple voxels in human brain simultaneously, with full signal intensity, no baseline distortion and minimal chemical shift displacement and signal loss due to T2 and J-modulation, thus allows regional maps of nine metabolites. The high SNR achieved in this study can allow the further improvement of spatial resolution.

1724.   Improved spRARE at 9.4T through water suppression with MEGA
Mélanie Craveiro1, Cristina Cudalbu1, Nicolas Kunz1,2, Vladimir Mlynárik1, and Rolf Gruetter1,3
1Laboratory for Functional and Metabolic Imaging, Ecole polytechnique fédérale de Lausanne, Lausanne, Switzerland, 2Division of Child Growth & Development, University of Geneva, Geneva, Switzerland, 3Departments of Radiology, Universities of Lausanne and Geneva, Switzerland

SpRARE is a fast spectroscopic imaging sequence that allows a good spectral resolution due to effective homonuclear decoupling. However, requirements such as high B1homogeneity and short echo spacing are mandatory to avoid signal loss of coupled metabolites. Moreover efficient water suppression (WS) is necessary to prevent from increased noise and artifacts in the spectra. In this study, MEGA water suppression was implemented in spRARE, which allowed the complete removal of the residual water signal, and the detection efficiency of the coupled metabolites by spRARE at 9.4T was demonstrated.

1725.   Spectroscopic Imaging of Glycine of Human Brain at 7.0 T
Sandeep K Ganji1,2, Abhishek Banerjee1, Elizabeth Maher3,4, and Changho Choi1,2
1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, United States, 2Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, United States, 3Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States, 4Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas, United States

In vivo spectroscopic imaging of Gly is challenging due to its low concentrations and the spectral overlap, primarily with myo-inositol. By going to higher field strengths this situation can improve due to increased spectral resolution. We employed an optimized chemical shift imaging method for glycine imaging at 7T and present preliminary data from healthy volunteers and tumor patients.

1726.   31P NMR Spatial Localization in Heart with Inhomogeneous Surface Spoiling Gradient
Adil Bashir1, Joseph J Ackerman2, and Robert J Gropler3
1Radiology, Washington University, St. Louis, MO, United States, 2Chemistry, Washington University, St. Louis, 3Radiology, Washington University, St. Louis

A 1D-CSI in combination with surface coil is widely used for 31P NMR spectroscopy of the heart. However, the discrete Fourier transform used to spatially construct low resolution phase encoded CSI data can lead to Fourier ringing. This contaminates the signal from the heart tissue with that from the chest muscles. In this work we demonstrate that using a superficial and highly non-linear field gradient the signal can be quickly and effectively localized to the deep lying heart tissue with little or no contamination. The applicability of the technique in phantom and animals is demonstrated.

1727.   Localised 31P MRS with a modified SPECIAL pulse sequence in mouse skeletal muscle at 7T
Isabell K. Steinseifer1, Patrícia M. Nunes1, Marnix C. Maas1, Tom W.J. Scheenen1,2, Andor Veltien1, Ralf Mekle3, Rolf Gruetter4, and Arend Heerschap1
1Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands, 2Erwin L. Hahn Institute for Mgnetic Resonance Imaging, Essen, Germany, 3Physikalisch-Technische Bundesanstalt, Berlin, Germany, 4EPFL, Lausanne, Switzerland

We present localized 31P MRS with a modified SPECIAL sequence of a 125µl voxel inside mouse skeletal muscle at 7T. By implementing a GOIA-WURST(16,4) pulse we overcome RF inhomogeneities and increased chemical-shift artefacts in slice selective localization caused by high-magnetic field. With a comparable time resolution we were able to obtain a similar SNR as with an FID measurement of the whole mouse leg. Artefacts caused by signal contamination from neighbouring bones were eliminated because of good localisation. The short echo time allowed acquisition of J-modulated ATP signals. We reached sufficient time resolution to follow ischemia in selected muscles.

1728.   31P MR spectroscopic imaging with nuclear Overhauser enhancement at 7T in the human prostate
Miriam W Lagemaat1, Marnix C Maas1, Thiele Kobus1, Andreas K Bitz2,3, Mark J van Uden1, Stephan Orzada2,3, Arend Heerschap1, and Tom W J Scheenen1
1Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands, 2Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen, Germany, 3Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany

In vivo 31P MRSI of the human prostate is potentially important in characterizing prostate cancer. We determined T1 relaxation times of the 31P metabolites and evaluated the NOE effect in the healthy human prostate at 7T to optimize the protocol in terms of sensitivity and measurement time for clinical use. A 31P MRSI sequence with a TR of 1.5s, flip angle of 45° and nominal voxel size of 1.9cm3 produces well-resolved spectra with up to 38% signal increase by NOE.

1729.   Combination of SPECIAL and 2D SSE Parallel Transmit Pulses for Volume Selection in MR Spectroscopy
Patrick Waxmann1, Tomasz Dawid Lindel1, Florian Schubert1, Bernd Ittermann1, and Ralf Mekle1
1Physikalisch-Technische Bundesanstalt, Braunschweig & Berlin, Germany

Starting with a SPECIAL sequence for localized spectroscopy, we kept the initial plane inversion pulse and replaced the conventional excitation pulse with a 4-fold accelerated 2D spatially selective excitation (SSE) pulse. A refocusing pulse is no longer needed for voxel definition and was eliminated, thus reducing the minimum echo time to 1.5 ms. This sequence allows to excite voxels of uniform thickness but arbitrary shape in two dimensions. It was implemented on a 3 T scanner equipped with 8 Tx channels. In phantoms, good spatial selectivity was demonstrated in imaging and spectroscopy experiments.

Localized Filtering for Optimal Fat Suppression in Parallel 1H MRSI
Thomas Kirchner1, Anke Henning1, and Peter Boesiger1
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland

A striking manifestation of the voxel-bleeding effect in MRSI in vivo is subcranial fat signal falsely appearing in a voxel in the center of the brain. We developed a localized filtering technique for the suppression of fat artefacts. Unlike k-space apodization techniques, we achieve artifact suppression without incurring fat signal spread at the edge of the object.

1731.   Signal Scaling Improves the Performance of Single-Voxel MR Spectroscopy Based on Segmented 2D-Selective RF Excitations
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 excitations are a promising tool to minimize partial volume effects in single-voxel MRS. Segmentation is often applied to avoid excessive 2DRF pulse lengths. But for some trajectories like the blipped-planar trajectory, segmentation reduces the signal efficiency because many segments cover only outer k-space lines and yield low flip angles and signal amplitudes. Here, it is shown that the signal-to-noise ratio can be increased significantly by applying all segments with the full flip angle and scaling down the acquired signal accordingly. This does not alter the signal amplitude but can reduce the noise level considerably as is demonstrated experimentally.

1732.   In-Vivo Localized Magnetic Resonance Spectroscopy in Small Animals Using Parallel Spatially Selective Excitation of Arbitrarily Shaped Volumes
Peter Ullmann1, Johannes T. Schneider1, Sarah R. Herrmann1, and Wolfgang Ruhm1
1Bruker BioSpin MRI GmbH, Ettlingen, Germany

Segmented parallel excitation (PEX) offers great potential for localized magnetic resonance spectroscopy (MRS) by allowing the excitation of arbitrarily shaped voxels which can be used to mitigate partial-volume effects and to increase SNR. In this study PEX-based spectroscopy was performed in a rat brain in vivo to assess the applicability of PEX for high-field small-animal MRS and to compare it to conventional selection methods. Results obtained at 9.4 T demonstrate that complex-shaped voxels adapted to the brain anatomy can be excited with good spatial selectivity and that spectra can be acquired thereof with improved SNR compared to cuboid-shaped spectroscopy voxels.

1733.   Voxel Based Transmit Gain Calibration using Bloch-Siegert Shift Method for MR Spectroscopy
Ralph Noeske1, Rolf Schulte2, and Timo Schirmer2
1Research and Collaboration, GE Healthcare, Berlin, Germany, 2GE Global Research, Munich, Germany

The SNR and excitation profile achievable by a localized MR spectroscopy experiment depends on the correct setting of the transmit gain (TG) to assure that the excitation pulses have correct flip angles across the prescribed ROI. Patient dependent spatial B1+-inhomogeneities require a voxel based TG calibration method to achieve this. Automated slice based techniques can yield to B1-miscalibration degrading excitation profile when B1-sensitive pulses are used. This study presents a voxel based TG calibration based on the Bloch-Siegert shift method embedded into a standard spectroscopy sequence and determining TG for the same volume that is excited for the spectroscopy experiment.

1734.   Highly Accelerated Parallel 1H MRSI at 7T with Simultaneous Suppression of Near- and Far-Reaching Signal Leakage
Thomas Kirchner1, Ariane Fillmer1, Peter Boesiger1, Klaas Paul Pruessmann1, and Anke Henning1
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland

We tailor the SENSE reconstruction algorithm towards accelerated parallel MRSI at ultra-high field strengths. Through calculation on an overdiscretized spatial grid and careful tuning of the spatial response function we achieve efficient suppression of signal contaminations caused by voxel bleeding without the increase of the effective voxel size that would be caused by conventional filtering techniques. We demonstrate up to 9-fold accelerated proton MRSI in vivo at 7T.
Traditional Poster Session - MRS, non-H1 & ESR

MRS Quantification
Click on to view the abstract pdf. Click on to view the poster (Not all posters are available for viewing.)
Tuesday 8 May 2012
Exhibition Hall  13:30 - 15:30

1735.   Optimized Reconstruction Parameters for Noise Modeling in Multi-Task Bayesian Compressed Sensing for Sparse 2D Spectroscopy
Trina Kok1, and Elfar Adalsteinsson1,2
1Massachusetts Institute of Technology, Cambridge, MA, United States, 2Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, United States

Metabolite spectra could be simulated and included as prior spectral information in the reconstruction of under-sampled 2D spectra via Multi-Task (MT) Bayesian CS. We previously showed that MT Bayesian CS successfully reconstructed peaks of Glu and Gln even with imperfect simulated metabolite spectra as priors. Spectroscopy data are intrinsically low SNR and here we extend previous work by incorporating noise modeling parameters for MT Bayesian CS and demonstrate improved reconstruction performance for under-sampled 2D spectra in CTPRESS compared to reconstruction without explicit noise modeling.

1736.   Measuring T1 and T2 and proton density in 3 acquisitions: the Tri-lower case Greek tau method
Guan Wang1,2, AbdEl-Monem El-Sharkawy1, William A. Edelstein1, Michael Schär1,3, and Paul A. Bottomley1
1Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States, 2Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, United States, 3Philips Healthcare, Cleveland, OH, United States

T1 and T2 are typically measured by separate partial saturation (PS) and spin-echo (SE) experiments. Here we present a new method to measure both T1 and T2 in just three acquisitions, without spin-echoes or varying the repetition period, TR. T2 is measured from two signals acquired with long- and short-duration adiabatic pulses. T1 is determined by varying the flip angle in two of the acquisitions. Thus, this 3-acquisition “Tri-tau” method employs a short α hard-pulse excitation, and short-and long-duration adiabatic β pulse excitations, all with TR≤T1. The method is validated with T1 and T2 SE and PS measurements on phantoms.

1737.   Refocused Double Quantum editing for lactate detection in the human calf muscle at 7T
Vincent Oltman Boer1, Peter R Luijten1, and Dennis W.J. Klomp1
1Radiology, UMC Utrecht, Utrecht, Utrecht, Netherlands

Double quantum filters suffer from severe signal loss if a long double quantum time is required. This is especially the case for applications in lipid rich environments such as fatty tumors or muscle tissue. Therefore a refocused double quantum filter was used that allows for the use of arbitrarily long dephasing gradients only at the cost of additional T2 loss. The lactate signal at rest and during exercise was detected in the human calf muscle after determination of the minimum required gradient area for complete lipid dephasing.

1738.   Model Free Approach to Kinetic Analysis of Real-Time Hyperpolarised 13C MRS Data
Deborah K. Hill1, Erika Mariotti2, Matthew R. Orton1, Jessica K. R. Boult1, Yann Jamin1, Simon P. Robinson1, Nada M. S. Al-Saffar1, Martin O. Leach1, Yuen-Li Chung1, and Thomas R. Eykyn1,2
1CRUK and EPSRC Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom, 2The Rayne Institute, Lambeth Wing, St Thomas Hospital, London, United Kingdom

While Dynamic Nuclear Polarisation is revolutionising the use of 13C MRS for real-time interrogation of metabolism, the complexity of the associated kinetic modelling used to extract rate constants for pyruvate-lactate exchange as a treatment biomarker lessens the immediate usefulness of the technique. We present a model-free approach to assessing treatment response in a range of cell lines, and show sensitivity to treatment response comparable to, yet much simpler in implementation than, kinetic modelling based on the modified Bloch equations.

1739.   Test-Retest Repeatability of Human Neurochemical Profiles Measured at 3 Versus 7 T
Melissa Terpstra1, Uzay E Emir1, Lynn E Eberly1, and Gulin Oz1
1University of Minnesota, Minneapolis, MN, United States

Although increased precision of metabolite quantification at ultra-high field has been demonstrated, accompanying improvements in test-retest reproducibility have not been evaluated. Therefore, 1H MR spectra were measured four times from each of four participants at both 3T and 7T. Outstanding spectral quality and reproducibility were achieved at 3T using commercially available hardware. While the Cramer-Rao lower bounds (CRLB) were universally lower at 7T than at 3T, the coefficients of variance (CV) were comparable at the two field strengths. Therefore, at the achieved spectral quality, factors other than quantification precision appear to limit inter-session reproducibility at 7T.

1740.   Dynamic B0 Variations in the Prostate
Catalina S. Arteaga de Castro1, Alex Bhogal1, Mariska P. Luttje1, Marco van Vulpen1, Juus Noteboom1, Peter R. Luijten1, Uulke A. van der Heide2, and Dennis W.J. Klomp1
1University Medical Center Utrecht, Utrecht, Netherlands, 2Netherlands Cancer Institute, Amsterdam, Netherlands

Variations of the main magnetic field can cause linewidth broadening and signal loss in long (8-10 min) MRSI experiments. In prostate MRSI a strongly coupled spin system (citrate) is observed. This spin system is sensitive to field variations, which can change the appearance of its peaks. Dynamic main field variations are observed in the prostate that exceed 15 Hz. These cause temporal susceptibility changes that explain the deteriorated spectrum. Second order B0 dynamic shimming simulations showed a gain of more than 10 Hz after correction of the B0 variations. Dynamic shimming can be implemented using localized navigators or field probes.

1741.   High sensitivity detection of targeted PFOB nanoparticles binding in a carcinoma mouse model using a new diffusion-weighted spectroscopy sequence
Céline Giraudeau1, Odile Diou2, Nicolas Tsapis2, Philippe Robert3, Caroline Robic3, Marc Port3, Denis Le Bihan1, Sébastien Mériaux1, Fawzi Boumezbeur1, Franck Lethimonnier1, and Julien Valette1,4
1NeuroSpin, I2BM, Commissariat à l'Energie Atomique, Gif-sur-Yvette, France, 2Univ Paris Sud, UMR CNRS 8612, Châtenay Malabry, France, 3Guerbet, Research Division, Roissy-Charles de Gaulle, France, 4MIRCen, I2BM, Commissariat à l'Energie Atomique, France

In the present work, an original spectroscopy sequence dedicated to PFOB and composed of a diffusion-weighted LASER module followed by an echo train is used to specifically detect angiogenesis in a carcinoma mouse model. We show that this sequence is more sensitive than a conventional LASER sequence and allows detection of sub-nanomolar concentrations of ávâ3-targeted PFOB nanoparticles. By selectively suppress signal coming from nanoparticles in the bloodstream, diffusion allows specific detection of angiogenesis on an individual animal. This method could be a novel concept to detect disease biomarkers by indicating the specificity of the signal provided by imaging.

1742.   Elimination of Frequency-modulated sideband artifacts for in vivo Non-Water Suppression MRS
Jyh-Miin Lin1, Tzu-Chao Chuang2, Wen-Chau Wu3, Hsiao-Wen Chung4,5, and Shang-Yueh Tsai6,7
1Department of Radiology, Duke University Medical Center, Durham, NC, United States, 2Department of Electrical Engineering, National Sun Yat-sen University, Kaohsiung, Taiwan, 3Graduate Institute of Oncology, National Taiwan University, Taipei, Taiwan, 4Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan,5Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan, 6Graduate Institute of Applied Physics, National Chengchi University, Taipei, Taiwan, 7Research Center for Mind, Brain and Learning, National Chengchi University, Taipei, Taiwan

In vivo MR spectra without solvent suppression often incur poor spectral quality due to gradient-induced frequency modulation(FM). We invented an algorithmic method to identify and eliminate these artifacts. Advanced algebraic tool was introduced to separate symmetric peaks with opposite phases from metabolites and baseline. Based on time-domain methods, the amplitude contaminated by FM components are adjusted according to the diagonal elements of matrices which have been triangularized. Our result shows improvement of spectral quality and quantitatively lower biases. This method may be easily integrated into the processing programs, whereas the sequence and experimental design can remain similar.

1743.   GABA detection in vivo: J-editing via homonuclear polarization transfer (JET)
Jeff Snyder1, and Thomas Lange1
1Dept. of Radiology, Medical Physics, University Medical Center Freiburg, Freiburg, Germany

A method to detect lower case Greek gamma-aminobutyric acid (GABA) in vivo is presented based on subtraction spectroscopy. The method (JET) requires no special selective pulses and is based on flip angle variation in PRESS. The technique was tested in healthy subjects at 3 T with quantification analysis by LCModel and compared to the MEGA editing sequence. The Cramer-Rao lower bounds for GABA illustrated increased detection accuracy for JET (11%) as compared to MEGA (14%), signifying JET as a viable GABA detection method.

1744.   Contamination-free measurement of GABA in the human brain by optimized PRESS at 7.0 T in vivo
Changho Choi1, Abhishek Banerjee1, Sandeep Ganji1, Ivan Dimitrov1, Subroto Ghose1, and Carol Tamminga1
1University of Texas Southwestern Medical Center, Dallas, Texas, United States

A comparison study of GABA measurement by optimized PRESS and difference editing (MEGA) at 7 T is presented. The PRESS TE was optimized as 92 ms for detection of the GABA 2.28 ppm resonance. MEGA was used to edit the 3.0 ppm resonance with TE = 70 ms. Data were acquired from the medial occipital cortex in 5 healthy volunteers. The GABA levels estimated with PRESS and MEGA were 0.80±0.06 and 1.15±0.16 mM (mean±SD, n=5) with reference to creatine at 8 mM, respectively. The GABA measures by PRESS and MEGA are discussed, focusing on contaminations from macromolecules and homocarnosine.

1745.   GABA Editing without Water Suppression
Roland Kreis1, Christine Sandra Bolliger1, Erin Leigh MacMillan1, Uwe Boettcher2, and Chris Boesch1
1Depts Clinical Research and Radiology, University Bern, Bern, Switzerland, 2Healthcare Sector, Customer Solutions Division, Siemens AG, Erlangen, Germany

MEGA PRESS editing is the most widely used technique for GABA measurements in human brain. Because it is an add/subtract method and measurement times are long, it is susceptible to small frequency, phase and amplitude drifts due to either patient related or technical instabilities. We have therefore combined it with non-water-suppressed MRS using the metabolite cycling technique to include the strong water signal in every acquisition as a reference signal. Editing parameters were optimized in vitro and in vivo for stability and sensitivity while retaining suppression efficiency for contaminating macromolecule signals.

1746.   Coil Combination of CSI Data Based on Reference Images at 7T
Bernhard Strasser1, Marek Chmelik1, Siegfried Trattnig1, Stephan Gruber1, and Wolfgang Bogner1
1Centre of Excellence, Department of Radiology, Medical University of Vienna, Vienna, Vienna, Austria

In this work the phase information obtained from a pair of gradient echo images is used for phasing CSI-data of 32 channels of a multi-channel-coil in order to sum up the signals of the coils and gain Signal to Noise Ratio compared to a Volume Coil. The additional 1.2 s measurement time is negligible. As a side benefit the resulting spectra are already correctly phased, leading to higher reproducibility, processing speed and accuracy of the fit. This method was tested in phantoms and healthy volunteers.

1747.   Correlation-based cross validation of PRESS, MEGA PRESS editing and 2D JPRESS at 3T
Ayse Sila Dokumaci1, Niklaus Zölch1, Michael Wyss1, Alexander Fuchs1, Peter Bösiger1, and Anke Henning1
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland

Neurotransmitters and antioxidants such as N-acetyl-aspartate (NAA), glutamate (Glu), glutamine (Gln), gamma-aminobutyric acid (GABA), and glutathione (GSH) play an important role in psychiatric pathophysiologies. Their detection in vivo can be performed by the dedicated 1H MRS methods such as PRESS using different echo times, MEGA-PRESS, and 2D JPRESS at 3T. However, the best method to be used is unknown. Therefore, in this work these methods were applied on 40 healthy volunteers and in 4 different brain regions for cross validation. PRESS sequence with the shortest echo time and JPRESS sequence were found to be the best candidates for this purpose.

1748.   Regional alterations of the brain macromolecule resonances investigated in the mouse brain using an improved method for the pre-processing of the macromolecular signal
Mélanie Craveiro1, Cristina Cudalbu1, and Rolf Gruetter1,2
1Laboratory for Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 2Departments of Radiology, Universities of Lausanne and Geneva, Switzerland

An accurate macromolecule (MM) knowledge is necessary to a reliable metabolite quantification. However, as MM signal acquisition is time-consuming and needs further pre-processing steps, a unique rodent MM signal is commonly used for quantifying mouse and rat brain spectra. We developed in this study a novel and accurate method to remove metabolite residuals from MM signals prior quantification. Moreover, we showed that potential regional alterations of the MM signal in the mouse brain and alterations between mouse and rat MM signals have no significant effects on metabolite quantification.

1749.   The Role of Higher Order B0 Shimming and Intrinsic Gray-White Matter Susceptibility on Spectral Resolution at 7T in the Human Brain
Jullie Pan1, and Hoby Hetherington1
1Neurosurgery, Yale University, New Haven, CT, United States

Potential improvements in SNR and spectral resolution are often cited as a primary advantage for MRSI in moving to higher field strength. However, the improvement in metabolite linewidth is governed by a number of factors including, macro and microscopic (óB0Macro, óB0Micro) inhomogeneity and the intrinsic T2. At 7T in superior brain locations after 4th order shimming the intrinsic susceptibility differences between gray and white matter represent a majority of the residual inhomogeneity. Metabolite resonances track the water resonance, leading to spectral broadening in voxels with both gray and white matter contributions.

1750.   ERETIC with automatic phase adjustment and eddy current correction compensation
Niklaus Zoelch1, Alexander Fuchs1, Peter Boesiger1, and Anke Henning1
1University and ETH Zurich, Institute for Biomedical Engineering, Zurich, Zurich, Switzerland

It is highly desirable to combine ERETIC with the Klose correction, which frees spectra from disturbing eddy current effects. So far this was only possible when drawbacks in the fitting procedure where accepted. In our work we increased the usability of ERETIC by implementing an automatic phase correction and eddy current correction compensation. Therefore for the first time the ERETIC peak and the metabolites peaks are simultaneously quantifiable using standardized freely or commercially available algorithms as LCModel.

1751.   In vivo absolute quantification for mouse brain tumor using an inductively coupled synthetic signal injection method
Donghoon Lee1, Kenneth Marro1, Mark Mathis1, Eric Shankland1, Cecil Hayes1, Stacey Hansen2, and James Olson2
1Department of Radiology, University of Washington, Seattle, WA, United States, 2Fred Hutchinson Cancer Research Center, Seattle, WA, United States

We obtained robust estimates of 31P metabolite content in mouse brain tumor using a synthetic signal injection method and an optimized, 1H/31P dual tuned probe. 31P metabolite concentrations were determined for brain tumors in a genetically engineered mouse model of medulloblastoma. The dual tuned 1H/31P probe was composed of a half volume coil and a second coil to allow injection of pseudo signals. In addition to in vivo 31P metabolite quantitation, 1H MR imaging was conducted to identify brain tumor and to determine tumor volume prior to 31P MRS.

1752.   Optimizing 2DJ experiments using Cramer Rao Minimum Variance Bounds
Christine Sandra Bolliger1, Chris Boesch1, and Roland Kreis1
1Depts Clinical Research and Radiology, University Bern, Bern, Switzerland

A method to optimize 2DJ experiments is presented. It is aimed at quantification of a set of metabolites and is based on searching acquisition parameters that yield minimal Cramer Rao Minimum Variance Bounds (CRBs). We present optimized experiments for GABA, glutamate, glutamine and glutathione quantification in human gray matter. Maxiumum-echo sampling was proven to provide a large benefit for all metabolites and careful selection of TEs can further lower the CRBs substantially. A further improvement can be achieved by optimizing what we call generalized 2DJ xperiments where arbitrary TEs and arbitrary number of scans per TE are used.

1753.   Going for glutamine: evaluation of asymmetric PRESS approaches
Caroline Rae1, Guangqiang Geng1, and Stephen R Williams2
1NeuRA, UNSW, Randwick, NSW, Australia, 2The University of Manchester, United Kingdom

Glutamine measurement is problematic using single-shot methods at 3T. Here, we evaluate in vivo, recommended PRESS timings, optimized asymmetric PRESS (A-PRESS) timings and a variant A-PRESS designed to minimize overlap of glutamine with the aspartyl moiety of NAA. Standard deviations of estimates were determined using the QUEST algorithm from jMRUI and appropriate metabolite basis sets. A-PRESS was found to be significantly better than PRESS for Gln determination and comparable with standard PRESS for glu, NAA, Cho and Cre. Use of the variant A-PRESS may also help improve estimate precision for Gln.

1754.   GABA quantification at 3 T: SPECIAL vs. MEGA-PRESS
Florian Schubert1, Ralf Mekle1, Simone Kühn2, Jürgen Gallinat3, and Bernd Ittermann1
1Physikalisch-Technische Bundesanstalt, Berlin, Germany, 2Psychology and Educational Sciences, Ghent University, Ghent, Belgium, 3Psychiatry and Psychotherapy, Charité University Medicine

MEGA editing has long been the method of choice for determination of the inhibitory neurotransmitter GABA. Novel spin echo based methods enabling ultrashort TE being potential competitors, we compared MEGA-PRESS and the SPECIAL technique that allows for very short TE. Spectra were acquired on 36 healthy subjects from 25x40x20mm3 comprising the anterior cingulate cortex using MEGA-PRESS at TE=68 ms and SPECIAL at TE=6.6 ms. GABA was fitted reliably (CRLB<20%) in all SPECIAL and 31 MEGA-PRESS spectra. Concentration estimates agreed reasonably well and were correlated. An added advantage of SPECIAL are good fit results for up to 12 more metabolites.

1755.   Standard space co-registration of 3D non-whole brain MRSI and regional metabolic quantification
Xiaodan YAN1, Ivan Kirov1, and Oded Gonen1
1Radiology, New York University, New York, NY, United States

Voxelwise analysis of 3D proton MR spectroscopic imaging: Absolute metabolic quantification in deep brain structures at 3 T Magnetic Resonance spectroscopy (MRS) and spectroscopic imaging (MRSI) in the human brain are both susceptible to: (i) repositioning error of the voxel (or grid) in cross-sectional and longitudinal studies; (ii) hypothesis error [inappropriate choice of region(s) of interest (ROI)]; and (iii) operator error in manual ROI outlining. These combine to increase the variance of localized metabolic quantification, i.e., reduce its sensitivity. To address these issues in order we (i) co-register the 3D MRSI data to the MRI and transform both into standard Talairach space; (ii) perform voxelwise statistical analysis on co-registered data from 10 healthy volunteers acquired annually over 3 years (40 data sets); and (iii) apply standard-space pre-defined deep brain structures (thalamus, putamen, globus pallidus, posterior cingulate cortex, corpus callosum, centrum semiovale and corona radiata) ROIs to preprocessed metabolic maps to extract their average metabolic concentrations. Voxelwise analysis reveals that most of the variance is at the volume-of-interest (VOI) edges due to positioning differences; within the VOI, CSF partial volume is the primary source of variance, followed by cross-subject fine scale differences at the level of gyri and sulci. The metabolic concentrations the and inter-and-intra- subject variance from each ROI were obtained, e.g., the concentrations for NAA, Cr, Cho, mI and Glu were 6.8±1.2, 5.2±0.9, 1.2±0.2, 3.9±0.7, 5.5±1.1 mM in the left thalamus and 6.8±1.5, 4.5±1.0, 1.2±0.3, 4.1±1.0, 4.7±1.1 mM in the left centrum semiovale. Finally, we also propose a protocol for voxelwise group comparisons for comparative studies.

1756.   Assessment of Automated Brain Region Directed 3D Proton Spectroscopy Data Analysis Pipeline
Jun Xu1,2, John D West1, Andrew J Saykin1, and Ulrike Dydak1,2
1Department of Radiology and Imaging Sciences, Indiana University School of Medcine, Indianapolis, IN, United States, 2school of Health Sciences, Purdue University, West Lafayette, IN, United States

An automated analysis of 3D MRSI data is being presented, which takes into account contributions from specific brain structures to each MRSI spectrum and thus allows obtaining brain region specific metabolite values. We demonstrate on the example of hippocampus data extracted from a 3D MRSI dataset that this type of brain-region specific analysis if more sensitive to small neurochemical changes occurring only in one brain structure, but not in adjacent ones, than current analysis methods. The method has been developed for an easy and sensitive comparison of metabolite levels of specific brain structures across groups in clinical studies.

1757.   Downsampling Strategies for MRS data
Alexander Fuchs1, Anke Henning2, and Peter Boesiger2
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Zurich, Switzerland, 2University and ETH Zurich

MR acquired data is usually sampled at higher much higher frequencies than the Nyquist condition. Before further processing this data needs to be downsampled to reduce the burden on storage requirements and processing time. Two commonly used downsample strategies are applied to ideal spectroscopic data and different artifacts related to these methods are identified. Especially in spectroscopy, artifacts in the initial time points of FIDs or phase distortions can lead to problems in further quantitative evaluations. Therefore a method is proposed that avoids the described problems and gives more reliable downsampled data.

1758.   ProFit revised
Alexander Fuchs1, Peter Boesiger2, and Anke Henning2
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Zurich, Switzerland, 2University and ETH Zurich

ProFit, a previously developed fitting tool for 2D JRPRES spectra was revised and certain drawback of the original implementation were tackled. Measured 2D JPRESS macromolecular baseline signals, surface splines to handle residual baseline distortions and a 2D model-free lineshape based on regularized splines were incorporated into ProFit. The results were compared between the recent and the revised version and it is shown that the inclusion of the these additional features together with a fine-tuned handling of prior knowledge leads to significantly better fit results.

1759.   Evaluation of correlation between lumbar disk degeneration level and fat content of multifidus by proton magnetic resonance spectroscopy
Chi-Cheng Wang1, Chien-Yu Liao2,3, Shin-Lin Shih1, and Chi-Long Juang3
1Department of Radiology, Mackay Memorial Hospital, Taipei, Taiwan, 2Medical Imaging, Medical Imaging, National Taiwan University Hospital, Taipei, Taiwan, 3Department of Radiological Technology, Yuanpei University, Hsin Chu, Taiwan

Philips 3.0T Magnetic Resonace Imagers were used to scan 30 low back pain patients and 30 healthy volunteers. T2 relaxation time maps of sagittal lumbar spine were acquired to obtain the averaged T2 values of inter-vertebral disc nucleus. Chemical shift Images of mutifidus muscle next to L4-L5 inter-veterbral disc were also acquired, neither water signal nor fat single were suppressed in order to calculate the fat/water ratio. After statistical analysis, our results indicated disc T2 values were highly correlated with fat content of multifidus.
Traditional Poster Session - MRS, non-H1 & ESR

MRS: Metabolism in Health & Disease
Click on to view the abstract pdf. Click on to view the poster (Not all posters are available for viewing.)
Tuesday 8 May 2012
Exhibition Hall  13:30 - 15:30

Age and breast density dependence of choline in breasts of healthy female subjects found using 3D-MRSI
Lenka Minarikova1, Wolfgang Bogner1, Marek Chmelik1, Katja Pinker-Domenig1, Hubert Bickel1, Thomas Helbich1, Siegfried Trattnig1, and Stephan Gruber1
1Centre of Excellence HF MR, Department of Radiology, Medical University of Vienna, Vienna, Austria

In previous studies, using single-voxel MR-spectroscopy or mutlivoxel MR-spectroscopy imaging (MRSI), choline signal with higher SNR was defined as a marker of malignancy in breast lesions. We present that choline signal can be detected using MRSI with high SNR in a large fraction of normal breast tissue and the SNR demonstrates an exponential correlation with breast density and age of the subject. Therefore, breast MRS-data from younger subjects with breast lesions should be interpreted with caution.

1761.   Using Diffusion-Tensor (DT-) MRI Calculated Fiber Orientation To Improve the Quantification of EMCLs and IMCLs.
Theodore F Towse1,2, Amanda KW Buck1, Jared A Godar3, and Bruce M Damon1,4
1Radiology, Vanderbilt University, Nashville, TN, United States, 2Institute of Imaging Science, Nashville, TN, United States, 3Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, United States, 4Institute of Imaging Science

Interest in quantifying myocelluar lipid content including extramyocellular lipids (EMCL) and and intramyocellular lipids (IMCL) as well as the rate of turnover of these lipids has increased recently due to the finding of increased IMCL in insulin resistant subjects, suggesting a possible role in the pathogenesis of diabetes. However quantification of these lipid moieties is not trivial due to the overlap between the IMCL and EMCL peaks in the 1H spectrum. We propose using the fiber orientation, as determined by diffusion-tensor (DT-) MRI, as prior knowledge in fitting the EMCL and IMCL peaks, thereby improving overall quantification.

1762.   Cholesterol detection in adipose tissue by natural abundance in vivo 13C MRS at 7T
Xing Chen1, Peter Boesiger1, and Anke Henning1
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Zurich, Switzerland

Adipose tissue is a major site of cholesterol storage. A variety of nutritional and metabolic alteration may influence the adipose tissue cholesterol level which has been studied in rats by chemical analysis. Localized natural abundance 13C MRS has been shown to be a powerful noninvasive technique for the study of lipids in vivo and has been applied to study the major classes of fatty acids. In this work, detection of cholesterol is reported for the first time noninvasively in human calf adipose tissue by 13C MRS at 7T, with J-refocused 1H PRESS localized DEPT sequence combined with broadband decoupling.

1763.   Prospective evaluation of liver steatosis comparing stereological point-counting biopsy analysis and 1H MRS
Mikael Fredrik Forsgren1,2, Mattias Ekstedt3, Olof Dahlqvist Leinhard1,2, Oscar Andregård4, Nils Dahlström2,5, Johan Kihlberg2,5, Stergios Kechagias6,7, Sven Almer7,8, Örjan Smedby2,5, and Peter Lundberg1,2
1Depts of Radiation Physics, Linköping University and Radiation Physics, UHL County Council of Ostergotland, Linköping, Sweden, 2Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden, 3Depts of Clinical and Experimental Medicine (IKE), Faculty of Health Sciences, Gastroenterology and Hepatology unit, Divison of Inlammation Medicine, Linköping University, Linköping, Sweden, 4Linköping University, Linköping, Sweden, 5Depts of Medical and Health Sciences (IMH), Division of Radiological Sciences, Linköping University, Linköping, Sweden, 6Depts of Medical and Health Sciences (IMH), Division of Cardiovascular Medicine, Linköping University, Linköping, Sweden, 7Depts of Endocrinology and Gastroenterology, UHL County Council of Ostergotland, Linköping, Sweden, 8Depts of Clinical and Experimental Medicine (IKE), Divison of Gastroenterology and Hepatology, Linköping University, Linköping, Sweden

Measuring the degree of liver steatosis is often important for treatment and prognosis in both a clinical and research context. The quantitative stereological point-counting analysis of biopsies has been shown to have high reproducibility, 1H MRS is a viable non-invasive method for liver fat content estimation. In this prospective study we have shown a good correlation between quantitative 1H MRS and stereological point-counting analysis of biopsies (Spearman rho = 0.90).

1764.   Lipid content and composition differ in adipose tissues and liver of ob/ob mice
Qiong Ye1, Alexander Fuchs1, and Markus Rudin1,2
1Institute for Biomedical Engineering, Zürich, Switzerland, 2Institute of Pharmacology and Toxicology, Zürich, Switzerland

Both fat content and their composition in adipose tissues and liver were accessed non-invasively with proton magnetic resonance spectroscopy in 34 weeks old ob/ob mice, a well-established murine model of obesity, using 9.4T system. In this work, spectra from different adipose tissues (subcutaneous fat pads at neck and belly as well as visceral fat) and from liver were compared. Liver showed a significant lower amount of lipids amount than three adipose tissues compartments. Lipids from lower belly displayed a higher degree of saturation. Furthermore, the fraction of polyunsaturated and monounsaturated lipids was found different among adipose tissues and liver.

1765.   Adiposity of the Lipodystrophic Heart
Michael D Nelson1, Vinaya Simha2, Edward Szczepaniak1, Ronald G Victor1, Abhimanyu Garg2, and Lidia S Szczepaniak1
1Cedars-Sinai Medical Center, Los Angeles, California, United States, 2UT Southwestern Medical Center, Dallas, Texas, United States

Obesity is associated with ectopic accumulation of fat in organs such as the heart, skeletal muscle and the liver. Seminal basic research suggests that excessive accumulation of fat in non-adipocytes triggers adverse signaling pathways ultimately leading to organ dysfunction. Patients with generalized lipodystrophies, have near total lack of body fat and provide the unique opportunity to study the effects of ectopic myocardial fat deposition in the absence of obesity. We propose that myocardial steatosis and associated lipotoxicity may be one of the mechanisms contributing to cardiomyopathy in patients with generalized lipodystrophy.

1766.   Blood contamination affects lipid quantification in cardiac 1H MR spectroscopy
Åsa Carlsson1,2, Maja Sohlin2, Maria Ljungberg1,2, and Eva Forssell-Aronsson1,2
1Department of Medical physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden, 2Department of Radiation Physics, University of Gothenburg, Gothenburg, Sweden

Proton MR-spectroscopy is an increasingly popular tool for studying the heart metabolism. For quantification, the triglyceride signal is often related to an internal reference. However, if the volume of interest (VOI) includes any of the ventricular blood those ratios might be affected. In this work, we investigated how the lipid quantification is affected by blood contamination by comparing spectra from VOIs fitted within the ventricular septum with spectra from VOIs enclosing the septum. It is shown that the lipid, water and creatin signal are differently affected by blood contaminations and hence, blood contamination will affect lipid quantification.

1767.   Decreased Cerebral Metabolism in Mice Exposed with Alcohol During Developmental Period
Anant Bahadur Patel1, Vivek Tiwari1, and Dev Ketan Thacker1
1NMR Microimaging and Spectroscopy, Centre for Cellular and Molecular Biology, Hyderabad, Andhra Pradesh, India

Brain development continues throughout gestation and postnatal period. As alcohol binds to glutamate and GABA receptors, exposure of alcohol during prenatal and postnatal period might affect the development of neurons and associated functions. Current study investigates the glutamatergic and GABAergic metabolism in the pups at P25 age obtained from dams exposed with alcohol during prenatal or postnatal period by using 1H-[13C]-NMR spectroscopy in conjunction with infusion of [1,6-13C2]glucose. Both, prenatal and postnatal exposure of alcohol to pups led to a reduction in glucose oxidation and neurotransmission associated with glutamatergic and GABAergic neurons.

1768.   Reduced Glutamatergic Activity Under Acute Alcohol Exposure
Anant Bahadur Patel1, Vivek Tiwari1, and Vaidyanathan Subramanian1
1NMR Microimaging and Spectroscopy, Centre for Cellular and Molecular Biology, Hyderabad, Andhra Pradesh, India

Alcohol is known to cause impairment of cognitive, psychological functions and neural activities. Ethanol modulates synaptic transmission in central nervous system upon its binding to NMDA, AMPA and GABAA receptors. The objective of current study was to evaluate the effect of acute alcohol on cerebral metabolism associated with glutamatergic and GABAergic neurons using 13C NMR spectroscopy in conjunction with infusion of [1,6-13C2]glucose in mice. Our findings indicate that acute alcohol treatment selectively impaired glutamatergic TCA cycle and neurotransmitter cycling without any significant change in GABAergic activity.

1769.   Reduced Glutamatergic Metabolism in Mice Cortex with different Level of Alcohol Exposure
Anant Bahadur Patel1, and Pandichelvam Veeraiah1
1NMR Microimaging and Spectroscopy, Centre for Cellular and Molecular Biology, Hyderabad, Andhra Pradesh, India

Effects of alcohol exposure via oral route on cerebral metabolism is not fully understood. In this study, we have investigated glutamatergic and GABAergic metabolism in cerebral cortex in mice exposed with different dose of alcohol via intra-gastric route. Acute treatment with alcohol at higher dose increased level of cortical GABA. Alcohol exposure selectively attenuates the excitatory activity without much changes in inhibitory function.

1770.   Evidence for Plasma Glutamine Uptake by Brain: Implications for Metabolic Modeling of 13C NMR data
Anant Bahadur Patel1, Henk De Feyter2, Douglas L Rothman2, Kevin L Behar3, and Puneet Bagga1
1NMR Microimaging and Spectroscopy, Centre for Cellular and Molecular Biology, Hyderabad, Andhra Pradesh, India, 2Diagnostic Radiolgy, Magnetic Resonance Research Center, Yale University, New Haven, CT, United States, 3Psychiatry, Magnetic Resonance Research Center, Yale University, New Haven, CT, United States

The steady state 13C enrichment of cortical glutamine (Gln) during intravenous infusion of [1-13C]/[1,6-13C2]glucose is ~25-30% lower than the corresponding glutamate enrichment. The source of this Gln ‘dilution’ is unknown. The contribution of plasma Gln to the cortical Gln dilution was assessed in anesthetized mice after intravenous [U-13C5]glutamine infusion. Cortical Gln 13C enrichment increased with time while total cortical metabolite levels were unaltered over a range of plasma Gln. The steady state labeling of cortical Gln-C4 appeared to be independent of plasma glutamine level. Basal plasma Gln could account for ~30-35% of glutamine dilution.

1771.   Neurochemical profile of Patients with Type 1 Diabetes Measured by 1H-MRS at 4 T
Silvia Mangia1, Anjali Kumar2, Amir Moheet2, Lynn Eberly3, Rachel Roberts3, Elizabeth Seaquist2, and Ivan Tkac1
1CMRR - Dept. of Radiology, University of Minnesota, Minneapolis, Minnesota, United States, 2Dept. of Medicine, University of Minnesota, Minneapolis, Minnesota, United States, 3Div. of Biostatistics, University of Minnesota, Minneapolis, Minnesota, United States

In this work we investigated differences in the neurochemical profiles of subjects with Type 1 Diabetes Mellitus (T1DM) relative to similarly aged healthy controls at the same level of plasma glucose using the increased sensitivity and spectral resolution of 1H-MRS at 4T. Data were analyzed from a group of 14 patients with long-standing T1DM (>10 years) and a group of 32 healthy controls. Levels of NAA and glutamate were lower by 6% in the grey matter of T1DM as compared to controls (p<0.005 and p<0.05, respectively), supporting the hypothesis that T1DM is associated with neuronal loss or dysfunction.

1772.   Common isoflurane anesthesia causes multiple changes of brain metabolism in mice
Susann Boretius1,2, Roland Tammer1,3, Thomas Michaelis1, and Jens Frahm1,3
1Biomedizinische NMR Forschungs GmbH, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany, 2Klinik für Diagnostische Radiologie, Universitätsklinikum Schleswig-Holstein, Kiel, Germany, 3DFG Center of Molecular Physiology of the Brain (CMPB), Göttingen, Germany

It is largely unknown how the brain metabolism is modified by volatile anesthetic agents like isoflurane in intact living organisms. Localized proton MRS in mice revealed a major increase of lactate and alanine by isoflurane. Further analysis of this phenomenon also revealed significantly increased GABA, choline containing compounds, and myo-Inositol. Glutamate initially increased but then decreased under constant isoflurane. Isoflurane effects were attenuated by suppression of the adrenergic nervous system and amplified by adrenergic stimulators. Apparently, MRS has a great potential of new insights into anesthesia. Brain studies using isoflurane anesthesia must take these metabolic changes into consideration.

1773.   Investigation on Neuroprotective Role of Caffeine against MPTP Induced Neurotoxicity in Mice using 13C NMR Spectroscopy
Puneet Bagga1, Suresh Kumar M1, and Anant Bahadur Patel1
1NMR Microimaging and Spectroscopy, Centre for Cellular and Molecular Biology, Hyderabad, Andhra Pradesh, India

MPTP is a well established neurotoxin which causes selective degeneration of dopaminergic neurons in substantia nigra leading to dopamine loss and hence PD. Neuroprotective effects of caffeine, a MAO-B inhibitor against MPTP were investigated using infusion of [1,6-13C2]glucose and 1H-[13C]-NMR spectroscopy in adult male C57BL6 mice. Treatment with MPTP led to loss of glutamatergic and GABAergic activity in cortex, striatum, thalamus-hypothalamus and olfactory bulb. Pretreatment with caffeine led to recovery of glutamatergic and GABAergic activity in cortex and olfactory bulb, but the same in striatum and thalamus-hypothalamus was only partially recovered, suggesting partial neuroprotection conferred by caffeine against MPTP neurotoxicity.

1774.   Influence of tissue specific macromolecule baseline on the metabolite quantification in human brain at 7 Tesla
Benoit Schaller1, Lijing Xin2, and Rolf Gruetter3
1Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Federale de Lausanne, Lausanne, Vaud, Switzerland, 2Department of Radiology, University of Lausanne, Lausanne, Switzerland, 3Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland

The accuracy of the metabolite quantification of short echo time is challenged by the broad baseline resonances underlying the whole 1H spectrum, identified as macromolecules (MM) and characterized by short T1 and T2. Macromolecule signal was acquired with a semi adiabatic IR SPECIAL sequence in two different tissues (white matter and grey matter, n=5 for each). Small but significant changes were found in the quantification Gln, Glu and NAA which are directly link the macromolecules signal differences in the region around 2.3-2.6ppm. A general in vivo measured MM baseline seems sufficient to ensure a reliable quantification of the metabolites.

1775.   Functional Diffusion-Weighted Spectroscopy (fDWS) of the human brain at 7T
Francesca Branzoli1, Aranee Techawiboonwong2, Sebastian Aussenhofer1, Andrew Webb1, and Itamar Ronen1
1C. J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, Netherlands, 2Department of Electrical Engineering, Mahidol University, Bangkok, Thailand

Here we propose functional Diffusion-Weighted Spectroscopy (fDWS) as a new method to investigate compartment-specific microstructural and metabolic changes related to neuronal activation. In this method a time series of alternating diffusion and non-diffusion weighted spectra is acquired, yielding a time-resolved series of apparent diffusion coefficient (ADC) values of metabolites correlated with neuronal activation. Especially, the detected changes in tCr and tCho ADCs can be exploited as a viable probe for brain activity, providing a tool for direct measurement of metabolic and microstructural changes during neuronal activation.

First direct 13C detection of glucose metabolism in the mouse brain at 9.4T using a 13C-cryo-coil
Markus Sack1,2, Gabriele Ende1, Alexander Sartorius2,3, and Wolfgang Weber-Fahr1,2
1Neuroimaging, Central Institute of Mental Health, Mannheim, Germany, 2Translational Imaging, Central Institute of Mental Health, Mannheim, Germany, 3Psychiatry and Psychotherapy, Central Institute of Mental Health, Mannheim, Germany

13C MRS suffers from an extremely low signal-to-noise ratio (SNR) compared to 1H MRI/MRS due to the low Larmor frequency and low natural abundance. Because of the small brain size the approach of dynamic 13C MRS in mice is even more challenging but provides the advantage of investigating mouse models. We present in vivo data from one of the first 13C-cryo-coils for mouse brain imaging using an ISISDEPT sequence and [1-13C]-enriched glucose on a 9.4T scanner. The obtained spectra show a good SNR and proof that the use of a cryo-coil is feasible for 13C MRS in the mouse brain.

1777.   Dynamic proton MRS in pediatric brain tumors with prominent citrate
Ida Ashoori1,2, Ashok Panigrahy1,3, Arabhi Nagasunder1,4, Girish Dhall5, Marvin D. Nelson1, and Stefan Blüml1,2
1Radiology, Childrens Hospital Los Angeles, Los Angeles, CA, United States, 2Rudi Schulte Research Institute, Santa Barbara, CA, United States, 3Pediatric Radiology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States, 4Radiology, Children's Medical Center, Dallas, Dallas, TX, United States, 5Hematology/Oncology, Childrens Hospital Los Angeles, Los Angeles, CA, United States

13C enriched (U-13C) glucose was administered orally to three pediatric brain tumor patients with prominent citrate and to four healthy controls. MR spectra, using a standard PRESS sequence were acquired before and after Glc administration. 13C label replaced 12C and resulted in an apparent reduction of the 1H MRS detectable breakdown products of glucose such as glutamate (Glu) in controls. In patients, citrate, an intermediate of the TCA-cycle, did not accumulate significant label. This is consistent with citrate being not actively involved in glucose metabolism.

1778.   Quantitative analysis of metabolites in mouse brain following heat exposure using magnetic resonance spectroscopy
Brian Andrews-Shigaki1,2, Yifan Chen1, Asamoah Bosomtwi2, Reed Selwyn2, and Haiying Tang2
1Military & Emergency Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States, 2Radiology & Radiological Sciences, Uniformed Services University of the Health Sciences, Bethesda, MD, United States

The effects of heat stress on the brain remain undetermined. Ee analyzed changes in metabolites from selected brain regions in mice following heat exposure using proton Magnetic Resonance Spectroscopy (1H-MRS). In the hypothalamus, significant decreases in NAA and Cr were shown 24 hours after heat exposure. In addition, significant increases in Glx were also demonstrated in the cerebellum. Results show no changes in metabolites in the hippocampus. Neuronal injury from heat stress is not homogeneously distributed in the brain and is localized hypothalamus. Increase of Glx in the cerebellum is unexpected and should be investigated further.

1779.   Different Types of COSY Applied To Study Glutamate and Glutamine in a Clinical Scanner
Saadallah Ramadan1, Hui Jun Liao Liao2, Alexander Lin2, and Carolyn Mountford2,3
1Centre for MR in Health, School of Health Sciences, University of Newcastle, Callaghan, New South Wales, Australia, 2Center for Clinical Spectroscopy, Brigham and Women's Hospital, Boston, MA, United States, 3Centre for MR in Healt, University of Newcastle, Callaghan, NSW, Australia

: Different types of COSY spectroscopy (adiabatic COSY, constant-time COSY, and localized COSY) are evaluated with a series of phantoms with variable concentrations of glutamate (Glu)/glutamine (Gln), to find out which sequence is the most optimal in determining relative amounts of Glu and Gln. While cross peaks obtained in the three types of COSY correlated well with total pool of Glu/Gln, they did not correlate with ratio of Glu to Gln.

1780.   Quantification differences of 1H spectra in human brain at 3 Tesla using the acquired macromolecule baseline or the built-in LCModel spline baseline
Benoit Schaller1, Lijing Xin2, and Rolf Gruetter1,3
1Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Federale de Lausanne, Lausanne, Vaud, Switzerland, 2Department of Radiology, University of Lausanne, Lausanne, Switzerland, 3Department of Radiology, Univerisities of Lausanne and Geneva, Switzerland

Macromolecules exhibit a broad signal underlying the entire 1H spectrum and inaccuracy in the measurement of the macromolecules might lead to systematic errors preventing an accurate and reliable quantification of the metabolites. Macromolecule signal was acquired with an IR SPECIAL sequence and then inserted into the LCModel basis sets. The choice of the built-in LCModel spline baseline and acquired in vivo macromolecules (n=3) yielded either minor (Ins, Cr, PCr, Glu around 8-25%) or major (GABA, PE, GPC around 36-68%) differences in the metabolites quantification. These substantial differences are mainly due to an underestimation of the macromolecule signal around 2-3.5ppm.

1781.   Field Dependence of PCr and ATP Linewidths and its Impact on In Vivo 31P MRS Studies
Xiao-Hong Zhu1, and Wei Chen1
1CMRR, Department of Radiology, University of Minnesota Medical School, Minneapolis, MN, United States

In vivo 31P MRS is useful for studying the brain high-energy phosphate metabolism and ATP energy, and its low intrinsic sensitivity can be partially overcome at high/ultrahigh field. One key benefit of the high field in addition to the sensitivity gain is the improvement in spectral resolution. However, the field dependence of 31P resonance linewidth or T2* is determined by two relaxation mechanisms: dipole-dipole and chemical shift anisotropy (CSA). The later will accelerate the linewidth broadening at higher field following B02 relation. To address this concern, we quantitatively investigated the field dependence of PCr, lower case Greek alpha-ATP and lower case Greek gamma-ATP linewidths based on the 31P MRS data of human and cat brains covering B0 from 1.5T to 16.4T. The overall results indicate large improvements in spectral resolution towards higher fields; they don’t support the notion that CSA could become the dominate T2* relaxation mechanism at high/ultrahigh field.

1782.   Enzymatic conversion of [1-13C]pyruvate to [1-13C]lactate in glioma rat model evaluated by 11.7T NMR correlated with DCE-MRI at 3T.
Jin Seo1, Hyun Jin Park1, Youn-Ki Nam2, Young Han Lee1, Ho-Taek Song1, and Jin-Suck Suh1
1College of Medicine, Yonsei University, Seoul, Korea, 2Agilent Technologies Korea Ltd., Seoul, Korea

Among the various metabolites involved in the glucose metabolism of the tumor, pyruvate and lactate are the highlighted metabolites in the up-regulated glucose metabolism of malignant neoplasm. The purpose of this study is to determine the enzymatic conversion of [1-13C]pyruvate to [1-13C]lactate with exclusion of magnetization transfer effect from the hyperpolarized 13C. Enzymatic conversion ratio of [1-13C]lactate/pyruvate in glioma and normal brain were evaluated ex-vivo by using 11.7T NMR. DCE-MRI elucidated the vascular permeability characteristics of highly metabolic glioma. In-vitro cellular LDH assay of C6 glioma cells proved enzyme activity. The conversion ratio and quantitative DEC-MRI parameter Kep were correlated.

1783.   Metabolic profiling of RG2 glioma using in vivo 1H MRS and ex vivo HRMAS 1H MRS
Vasile Stupar1,2, Coquery Nicolas2,3, Farion Régine1,2, Emmanuel Luc Barbier2,3, Chantal Rémy2,3, and Florence Fauvelle4
1Precilinical MRI Facility, Grenoble, France, 2U836, INSERM, Grenoble, France, 3Université Joseph Fourier, Grenoble, France, 4IRBA antenne CRSSA, La Tronche, France

In vivo 1H MRS can provide information regarding glioma growth and response to treatment. A wider range of metabolites can be obtained ex vivo in biopsies using HRMAS 1H MRS. The metabolic data can be interpreted and classified using multivariate pattern recognition methods, such as Projection to Latent Structure-Discriminant Analysis (PLS-DA). Comparison of metabolic profiles between 1H MRS and HRMAS 1H MRS is essential and the ability of both approaches to discriminate tumoral from normal tissue with statistical tools such as PLS-DA might help for diagnosis. We have used this approach in the rat RG2 model of glioma.

1784.   Unraveling the role of choline kinase in cancer
Noriko Mori1, Flonne Wildes1, Kristine Glunde1,2, Catherine Hudson3, and Zaver M Bhujwalla1,2
1JHU ICMIC Program, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States, 2The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, 3Vertex Pharmaceuticals (Europe) Ltd, Abingdon, Abingdon, Oxfordshire, United Kingdom

High choline kinase (Chk) expression and increased phosphocholine (PC) levels are frequently observed in aggressive cancers. Unraveling the role of Chk and PC will provide new insights in the malignant phenotype and lead to the development of treatments targeting this enzyme and choline metabolism. We previously observed that downregulating Chk expression with siRNA resulted in a significant reduction of PC and proliferation in breast cancer cells. Here we have found that a potent inhibitor of Chk activity reduced PC without altering cell proliferation, pointing to the importance of the enzyme, but not necessarily its activity, in breast cancer cell survival.

1785.   1H MR Spectroscopy of high grade prostate cancer
Thiele Kobus1, Jack Van Asten1, Alan Wright1, Arend Heerschap1, and Tom Scheenen1
1Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, Gelderland, Netherlands

PRESS and semi-LASER based 1H MRSI was performed in 17 patients with highly aggressive prostate cancer. The maximum choline plus creatine over citrate ratio and the maximum choline over creatine ratio were determined. Both metabolite ratios were very abnormal in all patients. The absence of frequency-selective lipid suppression in the semi-LASER sequence enables detection of metabolites in a broader frequency range. This enabled detection of an unassigned peak at 2.05 ppm. Although the identity of this resonance remains unknown, it was excluded that this resonance belonged to either spermine, glutamate or glutamine.

1786.   Effects of treatment on the metabolic characteristics of grade 2 and grade 3 gliomas
Alexandra Constantin1, Adam Elkhaled2, Llewellyn Jalbert1, Kenneth Smith2, Tracy McKnight2, Annette Molinaro2, Joanna Phillips2, Susan M. Chang2, and Sarah J. Nelson2
1University of California, Berkeley, Berkeley, CA, United States, 2University of California, San Francisco

The HRMAS metabolic profiles of recurrent and newly diagnosed grade 2 and 3 gliomas were compared in order to examine the changes that occur after treatment. Lower levels of myo-inositol/total choline (MCI) were found in recurrent gliomas. Higher levels of glutathione and MCI were detected in the recurrent grade 2 gliomas. Higher levels of taurine and aspartate and lower MCI levels were recorded in recurrent grade 3 gliomas compared to their newly diagnosed counterparts. Multivariate models were able to distinguishing between the recurrent and newly diagnosed tumors with more than 90% accuracy, suggesting that these lesions are metabolically distinct.

1787.   Altered Hepatic ATP Storage and Creatine Biosynthesis in Transgenic Mouse Liver Expressing Creatine Kinase
Kamaiah Jayalakshmi1,2, Min-Hui Cui1,3, Wei Zhang2, Laibin Liu2, Craig A. Branch1,3, and Chandan Guha2
1Gruss Magnetic Resonance Research Center, Albert Einstein College of Medicine, Bronx, New York, United States, 2Radiation Oncology, Albert Einstein College of Medicine,3Radiology, Albert Einstein College of Medicine, Bronx, New York, United States

31P MRSI has been employed to estimate hepatic phosphagen and ATP concentrations in transgenic mice expressing creatine kinase (CK-Tg) in liver with administration of cyclocreatine. A marked amount of phosphocyclocreatine was stored in liver of CK-Tg mouse with administration of cyclocreatine. In contrast, hepatic ATP concentrations decreased. These were accompanied by decreased serum creatine levels and increased urinary creatine levels. The significant amount of phosphocyclocreatine stored in CK-Tg mouse liver may serve as a false feedback corepressor of creatine biosynthesis since liver is usually lack of phosphagen. Abundant phosphocyclocreatine, a poor creatine kinase substrate, may also impede ATP production.

1788.   Cellular Responses to Tonicity: A High Field 1H and 23Na MR Microscopy Study
John James Walsh1,2, and Samuel Colles Grant1,2
1Center for Interdisciplinary Magnetic Resonance, The National High Magnetic Field Laboratory, Tallahassee, Florida, United States, 2Chemical & Biomedical Engineering, The Florida State University, Tallahassee, Florida, United States

The abdominal ganglia of the sea hare Aplysia californica was utilized to study the relaxation and diffusion properties of neurons in a tissue model under different osmotic states. Both 1H and 23Na MRI at 11.75 T were performed to quantify relaxation as a function of tonicity. The relationship of these parameters to cell volume changes can be used as a basis for understanding cell swelling, osmotic regulation and ionic redistributions in a neural tissue model and provide insight into the origins of sodium hyperintensities seen in ischemia and neurodegeneration.

1789.   Metabolic Effects and Biomarkers Identification on Nicotine-induced Intrauterine Growth Retardation with NMR-based metabonomic strategy
Jianghua Feng1
1Department of Electronic Science, Fujian Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, Fujian, China

NMR-based metabonomic strategy was used to investigate the metabolic responses to nicotine-induced dose- and time-dependent effects. Multivariate analysis of NMR data from respective pathophysiological regime including materal and fetal plasma and rat amniotic fluids revealed that nicotine ingestion caused the abnormal changes of glucose, lipid and protein metabolisms. Furthermore, under the defined screening principles, a set of small molecular metabolites in maternal plasma were selected out as the candidate biomarker served the diagnosis of IUGR. Although the specificity and universality of these biomarkers need a further investigation, the present study gives a new clue for the diagnosis and prevention of IUGR.

1790.   31P MRS as a Potential Biomarker for Fibromyalgia
Mikael Fredrik Forsgren1,2, Ann Bengtsson3, Olof Dahlqvist Leinhard1,2, Birgitta Sören3, Vaclav Brandejsky4,5, Eva Lund1,5, and Peter Lundberg1,2
1Depts of Radiation Physics, Linköping University and Radiation Physics, UHL County Council of Ostergotland, Linköping, Sweden, 2Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden, 3Depts of Rheumatology, University Hospital and Faculty of Health Sciences, Linköping, Sweden, 4Depts Clinical Research and Radiology, University Bern, Bern, Switzerland, 5Depts of Medical and Health Sciences (IMH), Division of Radiological Sciences, Linköping University, Linköping, Sweden

An impaired muscle energy metabolism in fibromyalgia (FM) patients has been suggested. The purpose of this study was to non-invasively analyze the content of phsophogens in the resting quadriceps muscle in FM patents compared to healthy controls using quantitative 31P MRS. Using an external reference for normalization we found significant group differences in PCr and NTP-Mg, suggesting that quantitative 31P MRS might be used as a biomarker for FM.

1791.   Evaluation of Subchondral Bone Marrow Lipids of Acute Anterior Cruciate Ligament (ACL) Injured Patients at 3T
Ligong Wang1, Nouha Salibi2, Gregory Chang1, Jenny T. Bencardino1, James S. Babb1, Andrew Rokito3, Laith Jazrawi3, Orrin Sherman3, and Ravinder R. Regatte1
1Radiology, New York University Langone Medical Center, New York, New York, United States, 2Siemens HealthCare, Malvern, PA, United States, 3Orthopaedic Surgery, NYU Langone Medical Center, New York, New York, United States

This study evaluated saturated lipids and unsaturated indices in different compartments of femoral-tibial bone marrow of acute anterior cruciate ligament (ACL) injured patients and compared to healthy controls and osteoarthritic (OA) patents at 3T. There were statistically significant differences (P<0.05) of unsaturation index between LT except LF in OA patients and LT, MF, MT in ACL injured patients; statistically significant differences also existed among different compartments of femoral-tibial bone marrow at 2.03ppm for saturated lipids (P < 0.02) between these two groups. OA patients have the highest saturated lipids at 2.03ppm compared to healthy controls and ACL injured patients.

1792.   Optimization of Acetyl-carnitine Detection in Human Skeletal Muscle by 7T 1H MRS
Jimin Ren1, Ivan Dimitrov1, A. Dean Sherry1,2, and Craig R Malloy1,3
1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, United States, 2Department of Chemistry, University of Texas at Dallas, Dallas, Texas, United States, 3VA North Texas Health Care System, Dallas, Texas, United States

Proton MR detection of low level of acetyl-carnitine (AcCtn) in skeletal muscle is limited by the contamination of dominant lipid signals. Lipid interference also makes spectral fitting difficult due to the irregular EMCL lineshape. In the current study, we utilize inversion-recovery technique to optimize the detection of AcCtn acetyl signal by eliminating the lipid contamination. The method is based on the T1 difference between acetyl signal (long T1) and the lipid signals (short T1) to null the lipid signals in the early phase of recovery process post-inversion, allowing a contamination-free acetyl signal to be obtained with a few minutes.

1793.   The cardiac triggering time delay is decisive for the spectrum quality in cardiac 1H MR Spectroscopy
Åsa Carlsson1,2, Maja Sohlin2, Maria Ljungberg1,2, and Eva Forssell-Aronsson1,2
1Department of Medical physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden, 2Department of Radiation Physics, University of Gothenburg, Gothenburg, Sweden

Localized cardiac MR-spectroscopy (CMRS) is an increasingly popular tool for evaluation of the heart metabolism. To receive good spectrum quality in the human myocardium the scanning needs to be cardiac triggered. In this work, the spectrum quality related to the choice of cardiac triggering time delay was investigated by comparing several spectrum quality parameters for different cardiac triggering time delays. It was shown that cardiac triggering in systole resulted in better spectrum compared to diastole. Each subject had an individual optimal cardiac triggering delay time that could be found approximately at 25 % of a full cardiac cycle.
Traditional Poster Session - MRS, non-H1 & ESR

MRS of Neurological Diseases
Click on to view the abstract pdf. Click on to view the poster (Not all posters are available for viewing.)
Tuesday 8 May 2012
Exhibition Hall  13:30 - 15:30

1794.   Characterization of Hepatic encephalopathy in vivo by using 31P-MRS; A preliminary animal study at 9.4 T
Juyeun Park1, YoonSeok Choi1, Yunjung Lee2, Jisu Woo3, In-Chan Song3, Ji-Hoon Kim3, and Hyeonjin Kim3
1Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Korea, 2Lee Gil Ya Cancer and Diabetes Institute, Incheon, Korea, 3Department of Radiology, Seoul National University Hospital, Seoul, Korea

Hepatic encephalopathy (HE) is a serious neuro-psychiatric complication of liver disease. To elucidate the pathogenesis of HE, 31P-MRS has been used. However, previous findings remain controversial due, at least in part, to relatively low sensitivity of the nucleus and limited spectral dispersion at low field. To this end, we have characterized HE in animal using 31P-MRS with substantially improved spectral dispersion and SNR at 9.4 T. Our results demonstrate that 31P-MRS at high field allows for highly resolved spectra in vivo, and thus can provide more vivid picture of the altered brain metabolism in the progression of HE.

1795.   Assessment of neurochemical alterations in rats exposed to long-term alcohol treatment
Do-Wan Lee1, Sang-Young Kim1, Hyunseung Lee2, Taehyeong Lee3, Changbum Yoo3, Jae-Hwa Kim4, Chi-Bong Choi5, Hwi-Yool Kim3, Dai-Jin Kim4,6, Kwan-Soo Hong2, and Bo-Young Choe1
1Department of Biomedical Engineering and Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul, Seoul, Korea, 2MRI Team, Korea Basic Science Institute, 3Department of Veterinary Surgery, Konkuk University of Korea, 4Department of Biomedical Science, College of Medicine, The Catholic University of Korea, 5Department of Veterinary Diagnostic Radiology, Dr. PET Animal Medical Center, 6Department of Psychiatry, Seoul St. Mary¡¯s Hospital, College of Medicine, The Catholic University of Korea

This study was aimed to investigate the cerebral neurochemical effects of long-term alcohol exposure on the adolescent rat frontal cortex. Our results show that GPC+PCh, Ins, Glx concentrations and (GPC+PCh)/NAA levels were significantly differed in frontal cortex of ethanol group. In particular, GPC+PCh concentrations and (GPC+PCh)/NAA levels showed most significant differences in ethanol group. Increased GPC+PCh concentrations and (GPC+PCh)/NAA levels may indicate that increased turnover of phosphatidylcholine and/or changed adaptive mechanism in frontal cortex of rat brain. Therefore, increased GPC+PCh concentrations and (GPC+PCh)/NAA ratio levels of frontal cortex might be utilized as key marker in long-term adolescent alcohol intoxication.

1796.   Longitudinal cerebral metabolic alternations in a novel macaque model of neuro-AIDS
Chunxia Li1, Xiaodong Zhang1,2, Amelia Komery2, Yingxia Li1, Hui Mao3, Francis J Novembre4, and James G Herndon2
1Yerkes Imaging Center,Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, United States, 2Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, United States, 3Department of Radiology, Emory University, Atlanta, Georgia, United States, 4Divisions of Neuroscience, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, United States

In this study, a novel macaque model of neuro-AIDS was employed to investigate the longitudinal cerebral metabolite alternation in asymptomatic patients with in vivo MRS at 3T. The results demonstrated that NAA was reduced significantly in the acute phase and Glx was reduced significantly in both acute and chronic phases after the SIV inoculation. The progressive alternations in NAA and Glx correlated significantly with the CD8 T cell %.

1797.   Correlation between Plaque Counts and Metabolite Concentrations in Transgenic Mouse Model of Alzheimer’s Disease
Malgorzata Marjanska1, Stephen D Weigand2, Geoffry L Curran2, Thomas M Wengenack2, Joseph F Poduslo2, Michael Garwood1, and Clifford R Jack, Jr.2
1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 2Mayo Clinic College of Medicine, Rochester, MN, United States

Previously, reduced levels of N-acetylaspartate (NAA) and glutamate (Glu) were observed in various mouse models of Alzheimer’s disease (AD). Dramatic increase in the concentration of myo-inositol (mIns) with age was observed for APP-PS1 mouse model of AD. Additionally, the treatment of transgenic AD mice with anti-Aβ antibody regimes appeared to slow the rate at which mIns normally increases in AD mice. In this project, we looked at the correlation between concentrations of metabolites obtained in vivousing 1H MRS just prior to sacrifice and the plaque counts obtained from histological Thio-S stained brain sections. Higher plaque counts were associated with lower NAA values and higher mIns values.

1798.   1H-MRS study of neurochemical profiles of human primary glioblastoma in mouse models at 9.4T
Abhishek Banerjee1, Tomoyuki Mashimo1, Sandeep K Ganji1, Kim Kangasniemi1, Todd Soesbe1, Elizabeth Maher1, Robert Bachoo1, and Changho Choi1
1University of Texas Southwestern Medical Center, Dallas, Texas, United States

Abnormal metabolisms in tumors have been reported in several studies. Here we present preliminary in vivo data of high field MRS of human glioblastoma implanted in NOD-SCID mouse brain using short echo time (TE = 19 ms) PRESS at 9.4T. Comparison between normal mice and mice with GBM is presented in terms of changes in concentration of metabolites and their ratios.

1799.   Magnetic Resonance Imaging and Spectroscopy Following Exposure to Chlorpyrifos
Roger J. Mullins1,2, Su Xu1,3, Jacek A. Mamczarz4, Edna F. R. Pereira4, Edson X. Albuquerque4, and Rao P. Gullapalli1
1Core for Translational Research in Imaging, University of Maryland, Baltimore, Baltimore, Maryland, United States, 2Program in Neuroscience, University of Maryland, Baltimore, Baltimore, MD, United States, 3Department of Diagnostic Radiology & Nuclear Medicine, University of Maryland, Baltimore, Baltimore, MD, United States, 4Division in Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland, Baltimore, Baltimore, MD, United States

Magnetic Resonance Imaging (MRI) and Spectroscopy (MRS) methods were evaluated for their ability to detect CNS changes following acute prepubertal exposure of guinea pigs to chlorpyrifos, an organophosphorus pesticide. Guinea pigs received a subcutaneous injection of either chlorpyrifos or peanut oil . One year later, imaging and spectroscopic changes were correlated with changes in spatial learning behavior in the Morris water maze (MWM). Chlorpyrifos-injected guinea pigs showed significant decreases in performance in the MWM that were associated with a reduction in hippocampal myo-inositol concentration. Results indicate that 1H MR spectroscopy may reveal subtle metabolic changes associated with detrimental organophosphorus exposure.

1800.   In vivo 1H-MRS reveals neurometabolic effects of a high fat diet
Janna L Harris1, William M Brooks1, In-Young Choi1,2, Hung-Wen Yeh3, and John A Stanford4
1Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, KS, United States, 2Department of Neurology, University of Kansas Medical Center,3Department of Biostatistics, University of Kansas Medical Center, 4Department of Molecular and Integrative Physiology, University of Kansas Medical Center

Recent evidence suggests a link between consumption of a high fat (HF) diet and cognitive decline. In order to better understand the effects of excess fat consumption on brain function, we maintained rats on a HF diet or standard low fat chow for 16 weeks before acquiring 1H-MRS in the hippocampus and striatum at 9.4T. In animals on the HF diet we observed changes in several metabolites including total creatine, total choline, glutamine, inositol, and glutathione. Collectively these data suggest that a HF diet produces disturbances in brain energy metabolism, cell membrane biodynamics, astroglial populations, and oxidative stress

1801.   Analysis of NAA in gene NAT8l knock out mice using proton Magnetic Resonance Spectroscopy
Brian Andrews-Shigaki1,2, Aryan M.A. Namboodiri3, Asamoah Bosomtwi2, Prasanth Ariyannur3, John Moffett3, Xianling Mao4, Dikoma Shungu4, Reed Selwyn2, and Haiying Tang2
1Military & Emergency Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States, 2Radiology & Radiological Sciences, Uniformed Services University of the Health Sciences, Bethesda, MD, United States, 3Anatomy, Phyisiology & Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States, 4Department of Radiology, Weill Cornell Medical College, New York, NY, United States

We characterized NAA concentrations in localized brain regions of the NAT8l knockout mouse by using proton magnetic resonance spectroscopy (1H-MRS). Four control and NAT8l knockout mice were scanned on a 7T Bruker scanner using a PRESS sequence. NAA concentrations were significantly decreased in the Cortex and Hypothalamus, with a less significant decrease in the Cerebellum. NAT8l knockout heterozygote mice have significantly decreased NAA levels in the brain. Further studies using these animals will be important for understanding the functional roles of NAA in the brain and its involvement in neurological and mental disorders.

1802.   MRS Biomarkers of Neurodegeneration in Spinocerebellar Ataxia type 1 (SCA1): Current and Future Potential
Uzay E Emir1, Diane Hutter1, Khalaf O Bushara1, Christopher M Gomez2, Lynn E Eberly1, and Gulin Oz1
1University of Minnesota, Minneapolis, MN, United States, 2University of Chicago, Chicago, IL, United States

A prior MRS study demonstrated neurochemical alterations in SCA1 using a 4T research scanner, however the feasibility of reliably detecting neurochemical alterations on clinical platforms remains to be investigated. We measured neurochemical profiles in the cerebellum and brainstem of patients with SCA1 and controls by 3T and 7T 1H MRS. Concentrations of major metabolites obtained at 3T and 7T were strongly correlated. Prior findings at 4T were reproduced at both 3T and 7T. In addition, the increased sensitivity at 7T enabled the reliable quantification of a higher number of neurochemicals than at 3T and the detection of additional neurochemical alterations.

1803.   Magnetic resonance spectroscopy (MRS) of the deep brain structures at 7.0T
Ravi Prakash Reddy Nanga1, David R Roalf2, Kejia Cai1, Mark Elliott1, Hari Hariharan1, James Loughead2, Harish Poptani1, Ravinder Reddy1, and Ruben C Gur2
1Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States, 2Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania, United States

Ultra-high field neuroimaging provides enhanced sensitivity and spectroscopic resolution. However, the increased field strength has several limitations, especially in deep brain regions which are prone to severe field inhomogeneities. Here, we show accurate and reliable quantification of glutamate/glutamine in deep brain structures (amygdala and hippocampus) at 7.0T. Given the importance of these deep brain structures in memory, emotion and other cognitive processes, accurate quantification could provide insight into the well-documented volumetric and functional differences in a variety of neuropsychological disorders.

1804.   Glutamate reduction in ALS patients observed with MR spectroscopy at 7T
Daniel Polders1, Esther Verstraete2, Vincent Boer1, Leonard H van den Berg2, Peter Luijten1, and Dennis Klomp1
1Radiology, UMC Utrecht, Utrecht, Netherlands, 2Neurology, UMC Utrecht, Utrecht, Netherlands

In this study, we utilized the increased SNR and chemical shift dispersion available with MRS at 7T to investigate selected metabolites in ALS patients and healthy controls. A single voxel (STEAM) measurement was performed, located in the sub-cortical white matter and covering the left motor tract. Fitting to a simulated basis set of nine metabolites and a separately collected macromolecular baseline showed significantly decreased levels of glutamate and N-acetylaspartylglutamate.

1805.   A 7T Combined 31P Spectroscopy and 1H MRI Study in Multiple Sclerosis
Manoj K Sammi1, Yosef A Berlow1,2, Thomas M Barbara1, Audrey H Selzer1, John W Grinstead3, Edward Kim4, Dennis Bourdette4, and William D Rooney1,2
1Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR, United States, 2Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, United States, 3Siemens Medical Solutions, Portland, OR, United States, 4Department of Neurology, Oregon Health & Science University, Portland, OR, United States

Mitochondrial dysfunction has been hypothesized to be a risk factor for neurodegeneration that leads to Multiple Sclerosis symptoms. Current work investigates and compares the normalized phosphorus metabolite signals in the brain over the same volume of interest in MS and healthy control subjects using phosphorus spectroscopic imaging at 7T while correcting for the signal contributions of gray matter, white matter, cerebrospinal and skeletal muscle tissue.

1806.   Reproducibility of glutamate measurement in the human brain with 1H-MRS at 7T: evaluation of the sLASER sequence
Anouk Marsman1, Vincent Boer2, Martijn Van den Heuvel3, Peter Luijten2, Hilleke Hulshoff Pol3, Dennis Klomp2, and René Mandl3
1Psychiatry, UMC Utrecht, Utrecht, Utrecht, Netherlands, 2Radiology, UMC Utrecht, Netherlands, 3Psychiatry, UMC Utrecht, Netherlands

1H-MRS at 7T can be used to accurately determine glutamate in the human brain. A sLASER sequence has been developed, using field focusing at short TE resulting in twice as much signal as can be obtained by using STEAM. To assess reliability and reproducibility of sLASER compared to STEAM, eight subjects were scanned twice with both sequences, in the frontal and occipital lobe. sLASER has significant intraclass correlations for glutamate in both locations, STEAM did not show any significant correlations. Thus, sLASER is a reliable method to obtain glutamate in the human brain at higher accuracy than physiological variability.

1807.   Characterization of gliomas using MRI and short echo 1-H MRSI at 7 Tesla
Yan Li1, Peder Larson1, Albert Chen2, Douglas Kelley1,3, Susan Chang4, and Sarah J Nelson1,5
1Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, United States, 2GE Healthcare, Toronto, Ontario, Canada, 3GE Healthcare, San Francisco, California, United States, 4Department of Neurosurgery, University of California, San Francisco, California, United States, 5Department of Bioengineering and Therapeutic sciences, University of California, San Francisco, California, United States

The purpose of this study was to compare metabolite ratios in the T2 lesion for 5 patients with glioma relative to ratios in 3 normal volunteers using H-1 MRSI. The use of 7 Tesla provided high SNR and spectral resolution. The presence of low Cho/Cr, NAA/Cr, Cho/Cr and mI/Cr were suggestive of edema, while high Cho/Cr and low NAA/Cr were interpreted as active tumor and low NAA/Cr and high mI/Cho as being suggestive of treatment effects. Our results suggest that using a combination of metabolite ratios would be helpful in the interpretation of treatment response.

1808.   Brain Chemical Concentrations in Autism Spectrum Disorder at 6, 12 and 24 Months as Measured with Magnetic Resonance Spectroscopic Imaging
Neva M Corrigan1, Mindy Olson2, Todd Richards1, Dennis WW Shaw1,2, Annette Estes3,4, Stefan Posse5, and Stephen R Dager1,3
1Radiology, University of Washington, Seattle, WA, United States, 2Seattle Children's Hospital, Seattle, WA, United States, 3Autism Center, University of Washington, Seattle, WA, United States, 4Speech and Hearing Sciences, University of Washington, Seattle, WA, United States, 5University of New Mexico, Albuquerque, NM, United States

Brain imaging research has demonstrated alterations in brain volume and chemistry in children with autism spectrum disorder (ASD) at 2-5 years of age. The mechanisms and time of onset of these abnormalities are unknown. Magnetic spectroscopy provides chemical information that may help elucidate the cellular mechanisms that lead to the observed structural alterations as well as abnormal behavioral features characteristic of this disorder. We present findings from 3D MR spectroscopic imaging of children at higher risk for developing of ASD at 6, 12 and 24 months of age and compare them to findings for children at lower risk for developing ASD.

1809.   Decreased Basal Ganglia Neuronal Metabolism and Perfusion of Patients With Chronic Symptoms Following a Mild Traumatic Brain Injury.
Brenda Bartnik Olson1, Harrison Wang1, Sarah Uffindell2, Stephen Ashwal3, Valarie Wong4, Karen Tong1, and Barbara Holshouser1
1Radiology, Loma Linda University, Loma Linda, CA, United States, 2Neurology, Loma Linda University, Loma Linda, CA, 3Pediatric Neurology, Loma Linda University, Loma Linda, CA, 4Redlands Pediatric and Adult Medicine, Redlands, CA

Approximately 80% of traumatic brain injuries (TBI) are classified as mild with persistent deficits occurring in ~50-80%. Using 3D magnetic resonance spectroscopic imaging and DSC-perfusion weighted imaging we demonstrate decreased NAA/Cr and cerebral blood flow in multiple brain regions in a population of mild TBI patients with persistent symptoms. In the basal ganglia, the percentage of voxels with decreased NAA strongly correlate to the decrease in CBF. These findings may reflect decreased neuronal activity or a reduction in neuronal volume and could suggest a role for basal ganglia dysfunction in the pathophysiology of persistent deficits following a mild TBI.

1810.   Thalamic Hypometabolism in mTBI: Insight from Data Driven Voxelwise Analysis of 3D 1H-MR Spectroscopy Imaging
Xiaodan YAN1, Ivan Kirov1, and Oded Gonen1
1Radiology, New York University, New York, NY, United States

Traumatic brain injury (TBI) and related disabilities affect nearly 5.3 million people in the U.S, imposing a costly economic burden of about $56 billion. Diagnosis based on the Glassgow Coma Scale (GCS) indicates that 85% of TBI cases are mild (GCS:13-15). Mild-TBI (mTBI) pathology was previously believed to be “microscopic” and “diffuse” diseases. 1H MR spectroscopy imaging (MRSI) is a noninvasive technique for detecting microscopic and metabolic changes in the brain. In order to investigate whether there are focal metabolic changes associated with mTBI, a data-driven voxelwise analysis was adapted after MRSI data was co-registered to a standard space. This rigorous statistical approach avoids the bias and errors from manually outlining regions of interest (ROI-s).Significant group difference is found for NAA, Cr, Cho and mI in left thalamus (p < 0.01), and significant difference for Cho and NAA (p < 0.05) in right putamen, with mTBI patients showing decreased concentrations. Hypoactivity at thalamus, as well as decreased thickness of thalamus and putamen was also reported in previous studies. The hypometabolism in the present study together with hypoactivity in previous relevant studies, indicate dysfunction of thalamus and putamen may contribute to mTBI pathology.

Can Early 1H-MRS Predict Tissue Loss in Traumatic Brain Injury?
Janna L Harris1, In-Young Choi1,2, Phil Lee1,3, Hung-Wen Yeh4, and William M Brooks1
1Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, KS, United States, 2Department of Neurology, University of Kansas Medical Center,3Department of Molecular and Integrative Physiology, University of Kansas Medical Center, 4Department of Biostatistics, University of Kansas Medical Center

A traumatic brain injury (TBI) initiates a progressive neurodegeneration that develops over days to weeks following the initial physical impact. We used 1H-MRS one hour after experimental TBI in rats to examine two brain regions: a proximal VOI containing tissue destined to degenerate into a lesion cyst, and a more distal VOI that would not develop any overt MR-visible lesion. Our results demonstrate a different early spectroscopic profile in tissue destined to degenerate vs. tissue destined to survive. We propose that 1H-MRS early after TBI could be useful for predicting the extent and location of ultimate tissue damage in TBI patients.

1812.   Is “metabolic connectivity” across spared non-primary motor areas altered in stroke?
Carmen M Cirstea1,2, Hung-Wen Yeh1,3, Anda E Popescu1, Ali Bani-Ahmed1,2, In-Young Choi1,4, Phil Lee1,5, Sorin Craciunas6, and William M Brooks1,4
1Hoglund Brain Imaging Center, University of Kansas, Kansas City, KS, United States, 2Departments of Physical Therapy, 3Biostatistics, 4Neurology, 5Molecular & Integrative Physiology, University of Kansas, Kansas City, KS, 6Neurosurgery Unit IV, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania

Although metabolite abnormalities have been documented in survivors of stroke by magnetic resonance spectroscopy, the relationship between metabolites in discrete anatomic areas that form cognitive networks is less well understood. Our goals were to establish evidence of "metabolic connectivity" in normal brain and to determine whether such connectivity was altered in radiologically normal appearing cortex following a sub-cortical stroke.

1813.   Noninvasive detection of 2-hydroxyglutarate in gliomas by 1H MR spectroscopy at 7.0 T in vivo
Changho Choi1, Sandeep Ganji1, Abhishek Banerjee1, Ivan Dimitrov1, Ralph DeBerardinis1, Craig Malloy1, Bruce Mickey1, Robert Bachoo1, and Elizabeth Maher1
1University of Texas Southwestern Medical Center, Dallas, Texas, United States

Mutations in isocitrate dehydrogenase (IDH) 1 and 2 in the majority of WHO grade-2 and -3 gliomas and secondary glioblastomas lead to production of 2-hydroxyglutarate (2HG) and are associated with longer overall survival compared to IDH wild-type gliomas. Here we report preliminary in-vivo 2HG measures by 1H-MR spectroscopy at 7 T. The echo time of PRESS was optimized as 92 ms for detection of the 2HG multiplet at 2.25 ppm. The performance of this optimized TE PRESS is discussed together with short TE PRESS (34 ms).

1814.   Detection of the cerebral acetone signal elevated in the STZ-induced diabetic rats measured by in vivo 1H MRS at 9.4 T
In-Young Choi1,2, Ping-Chang Lin1, Wen-Tung Wang1, and Phil Lee1,3
1Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, Kansas, United States, 2Neurology, University of Kansas Medical Center, Kansas City, Kansas, United States, 3Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, United States

Diabetic ketoacidosis is a serious condition characterized by elevated levels of ketone bodies that may lead to diabetic coma or even death in patients, particularly, with type-1 diabetes. Detection of changes in ketone body levels in the brain should help to detect ketoacidosis in hyperglycemic state. In this study, we identified a cerebral acetone signal at 2.22 ppm and significantly elevated levels of both acetone and beta-hydroxybutyrate (bHB) along with the elevation of glucose concentration in a rat model of streptozotocin-induced diabetes using 1H MRS at 9.4T. A moderate correlation between bHB and acetone was also observed.

1815.   Scyllo-Inositol detection in the human spinal cord
Andreas Hock1, Fuchs Alexander1, Erin L. MacMillan2, Roland Kreis2, Spyros S. Kollias3, Peter Boesiger1, and Anke Henning1
1University and ETH Zurich, Institute for Biomedical Engineering, Zurich, Switzerland, 2University of Bern, Dept. of Clinical Research, Bern, Switzerland, 3Institute of Neuroradiology, University Hospital of Zurich, Zurich, Switzerland

Scyllo-Inositol (sI) is one of the stereoisomers of inositol yielding to a singlet resonance at a chemical shift of 3.35 ppm in 1H MR spectroscopy (MRS). This work represents the first report of sI detection in the human spinal cord, which was enabled by non-water suppressed metabolite cycled 1H MRS at 3T. The results show an increased mI/Creatine and sI/Creatine ratio compared to the brain which might be an indicator of a different metabolism in the spinal cord.

1816.   Brain Atrophy in MS Patients Correlates with Creatine Concentrations
Anders Tisell1,2, Olof Dahlqvist Leinhard1,2, Jan Bertus Marcel Warntjes1,2, Anne-Marie Landtblom3,4, and Peter Lundberg2,5
1Division of Radiological Sciences, Department of Medicine and Health Sciences, Linköping University, Linköping, Sweden, 2Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden, 3Neurology, Department of Clinical and Experimental Medicine, Division of Neuroscience, Linköping University, Linköping, Sweden, 4Neurology Clinic, UHL, County Council of Östergötland, Linköping, Sweden, 5Depts of Radiation Physics, Linkoping University and Radiation Physics, UHL County Council of Östergötland, Linköping, Sweden

Absolute quantitative MRS and quantitative MRI was used to assess the difference of NAWM between MS patients with non or a low number of MS lesions, MS patient with MS lesions, and healthy controls. Elevated levels of total glutamine + glutamate was observed in both investigate phenotypes of MS compered to healthy controls. In contrast elevated myo-Inositol, Choline containing compounds and lower levels of N-acetyl aspartate glutamate was only observed in NAWM of MS patients with several lesions. Furthermore a correlation between atrophy and increased total creatine + phosphocreatine was also observed in NAWM of MS patients.
Traditional Poster Session - MRS, non-H1 & ESR

MRS of Normal & Aging Brain
Click on to view the abstract pdf. Click on to view the poster (Not all posters are available for viewing.)
Tuesday 8 May 2012
Exhibition Hall  13:30 - 15:30

Proton T1 relaxation times of metabolites in human occipital white matter and grey matter at 7T
Lijing Xin1, Benoit Schaller2, Vladimir Mlynarik2, Huanxiang Lu3, and Rolf Gruetter1,2
1Department of Radiology, University of Lausanne, Lausanne, Switzerland, 2Laboratory of functional and metabolic imaging, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 3Institute of Surgical Technologies and Biomechanics, University of Bern, Switzerland

In this study, T1 relaxations of 1H resonances (singlets and J-coupled peaks) of brain metabolites in occipital white matter and grey matter were measured at 7T using an inversion recovery semi-adiabatic SPECIAL sequence. T1 values of metabolites ranged from 900-2100ms and those of GSH, scyllo-Ins, Tau and NAAG were determined for the first time. T1 of NAA, tCho, Glu and NAAG were significantly different in WM and GM. The reported values will be useful for the quantification of metabolites by MR spectroscopy at 7T.

1818.   Rapid Multi-Echo Measurement of Brain Metabolites T2 values at 7T Using a Single-Shot Spectroscopic CPMG Sequence and Priors
Ece Ercan1, Andrew Webb1, and Itamar Ronen1
1C. J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, Netherlands

We present a rapid method for the robust and accurate estimation of brain metabolite relaxation rates based on a single-shot CPMG sequence with multiple echoes. Each echo consists of a small number of acquired time-domain points. These truncated data sets are subsequently extended with additional data points calculated via solving a set of linear equations for the peak amplitudes using previously estimated frequencies and linewidths as priors. These priors are obtained from a short single volume MRS experiment with subsequent linear prediction using singular value decomposition (LPSVD) processing.

1819.   Age dependence of NAA and tCr transverse relaxation times determined in hippocampus and frontal cortex at 3T
Bernadeta Walaszek1, Florian Schubert1, Ralf Mekle1, and Bernd Ittermann1
1Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany

In absolute metabolite quantification at moderate to long echo times, most often for T2 correction the global transverse relaxation times are used. However, it has been shown that the metabolite T2s may differ individually and depend on the brain region. Additionally, the process of ageing of the human brain, may affect the metabolite transverse relaxation times. Given the increasing importance of metabolite quantification in the hippocampus as well as in cortical areas of the brain, we determined T2 values of relevant brain metabolites in these brain regions using PRESS, and studied their age dependence.

1820.   Metabolite 1H transverse relaxation rates measured in the healthy young versus elderly human brain at 4 T
Uzay E Emir1, Malgorzata Marjanska1, Dinesh Deelchand1, and Melissa Terpstra1
1University of Minnesota, Minneapolis, MN, United States

Differences in T2 among experimental groups can confound quantification of metabolite concentrations. Existence of such differences in young versus elderly human subjects is controversial. This study used STEAM spectroscopy at several echo times to measure T2 at ultra high magnetic field (4 T) in 29 young (age 18-22) and 32 elderly (age 70+) subjects. Artifact free spectra allowed for reliable determination of signal strengths via LCModel, which led to good fitting of the data to the T2 relaxation curve for each metabolite. The T2's were faster in the elder than in the young subjects (p<0.01) for all metabolites.

1821.   In Vivo 17O Measurements of Water Rotational Correlation Time and Hydrodynamic Radius in Rat Brain
Xiao-Hong Zhu1, and Wei Chen1
1CMRR, Department of Radiology, University of Minnesota Medical School, Minneapolis, MN, United States

This study aims to exploit new MR approaches for noninvasively measuring the rotational correlation time (lower case Greek tauc) and hydrodynamic radius (Rh) of the brain tissue water. In vivo17O MRS was used to measure T1 of the quadrupolar 17O spin of water in the rat brain at 9.4T, and to calculate lower case Greek tauc according to a simple, field-independent relation. 1H MRI was applied to image the brain translational diffusion coefficient (Dt); and the value of Rh was derived from the Dt/T1 ratio. It was found that i) the brain water lower case Greek tauc was in a range of several picoseconds and sensitive to brain temperature change, ii) Rh was about 1 Å that is in line with the water molecular size. This work indicates excellent utilities of in vivo 17O MRS for potentially imaging the microscopic matrix of brain tissue water properties in vivo.

1822.   Estimation of GABA and Glutamergic Contents in Occipital Lobe and Cerebellum By1H MR Spectroscopy
Saadallah Ramadan1, Tapan Biswas2, Keith Heberlein3, Mark Brown4, and Alexander Lin5
1School of Health Sciences, University of Newcastle, Callaghan, New South Wales, Australia, 2Biswas X Ray & Scan Center, West Apcar gardens, Asansol, India, 3Siemens Medical Solutions, Charlestown, MA, United States, 4Training and Development Center, Siemens Healthcare, Cary, NC, United States, 55Center for Clinical Spectroscopy, Brigham and Women's Hospital, Boston, MA, United States

: Glx and GABA were measured in cerebellum and occipital lobe of human brain (n=24). Ratio of Glx peaks at 3.8 and 2.3 ppm, as well as GABA peak at 3.0ppm to NAA was calculated. Higher levels of GABA and Glx were found in cerebellum. This is in accordance with known function of cerebellum in

1823.   Reduced Glucose Oxidation by Glutamatergic Neurons in Cerebral Cortex during Normal Aging in Mice
Anant Bahadur Patel1, Pandichelvam Veeraiah1, Mohammad Shameem1, and Vivek Tiwari1
1NMR Microimaging and Spectroscopy, Centre for Cellular and Molecular Biology, Hyderabad, Andhra Pradesh, India

Changes in mitochondrial function at the cellular level is not fully understood under normal aging. Present study investigates glucose oxidation by glutamatergic and GABAergic neurons, and neurotransmitter cycling in adult and aged mice. Cortical glutamate level was found to be reduced in aged mice. The glucose oxidation by glutamatergic neurons was decreased in aged mice while GABAergic functions seems to be unperturbed.

1824.   GABA concentration in left and right sensorimotor cortex is correlated across individuals
Nicolaas AJ Puts1,2, C John Evans3, David J McGonigle3, and Richard AE Edden1,2
1Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, Baltimore, MD, United States, 2FM Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 3CUBRIC, School of Psychology, Cardiff University, Cardiff, United Kingdom

Inter-individual differences in GABA concentration can shed light on the role of inhibition in cognitive processes. To date, several studies have shown that GABA concentration in functionally unrelated regions does not correlate between individuals. In this study we test the hypothesis that GABA concentration in two functionally related regions, right and left sensorimotor cortex, correlates across individuals.

1825.   Brain MRS after Consumption of Commercially Available Energy Drink
Saadallah Ramadan1, Tracy Burrows1, Kirrilly Pursey1, and Peter Stanwell1
1School of Health Sciences, University of Newcastle, Callaghan, New South Wales, Australia

1H One-dimensional (1D) spectroscopic data from a single voxel in the bi-occipital lobe were acquired from a group of Red Bull drinkers (n=4) and another control group(n=5). Each subject was monitored for more than 45 minutes with a 1D spectrum acquired every 5 minutes on a 1.5 T Achieva XR MR scanner (Phillips, The Netherlands). Data was processed and analyzed using LcModel. Data revealed a decrease in PCr, Ins, and MM20, and an increase in GSH and Glx as a result of drinking Red Bull.

1826.   1H-MRS changes in the rat brain due to circadian cycle
Serguei Liachenko1, and Jaivijay Ramu1
1NCTR / FDA, Jefferson, AR, United States

Circadian clocks regulate many physiological processes in biological systems. The diurnal changes in these processes may result in different sensitivity to pharmacological intervention as well as to the toxicity. Current study investigated the diurnal differences in neurometabolic profiles of naïve adult rats using proton MRS

1827.   High resolution spectroscopic imaging of the mouse brain using a cryogenic 2x2 phased array coil at 9.4T
Aline Seuwen1, Sandra Bürgi1, Aileen Schröter1, and Markus Rudin1,2
1Institute for Biomedical Engineering, University and ETH, Zürich, Switzerland, 2institute of pharmacology and toxicology, University Zürich, Switzerland

Spectroscopic imaging (SI) on the mouse brain is an attractive tool to quantitatively determine brain metabolite concentrations on different models of human diseases. However, SI suffers from low signal-to-noise ratio and long acquisition times, which restrain the practically achievable spatial resolution. In this work, a novel receive-only cryogenic phased array coil was used to overcome those issues. Using this setup, we could acquire spectra of excellent quality on a mouse model of glioblastoma at resolutions of 0.32 µl per voxel in less than 2h.