ISMRM 24th Annual Meeting & Exhibition • 07-13 May 2016 • Singapore

Traditional Poster Session: Spectroscopy

2351 -2364 MRSI
2365 -2403 MRS Methods
2404 -2421 Metabolic Profiling

Rosette Spectroscopic Imaging (RSI) of human brain at 7T
Claudiu Schirda1, Tiejun Zhao2, Hoby Hetherington1, Victor Yushmanov1, and Jullie Pan1
1Radiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States, 2Siemens Medical Solutions, Pittsburgh, PA, United States
Rosette Spectroscopic Imaging (RSI) has been shown to provide similar or superior encoding speed and sensitivity to echo-planar (EPSI) and spiral spectroscopic imaging (SSI), while using much lower peak gradient and slew rates. Fully encoded k-t space 3D acquisitions with 0.4ml voxel size in 7.2mins (20x20x12, spectral width SW=1923Hz --6.47ppm, Gmax=7.1mT/m and Smax=86mT/m/ms), and 2D acquisitions as short as 36s (1cc) to a 9.5min dual-echo TE=17/34ms J-refocused with 0.16ml voxel (4mm in-plane, 48x48, SW=2778Hz --9.35ppm, Gmax=5.1mT/m and Smax=18mT/m/ms) were collected at 7Tesla in phantoms, controls and patients with epilepsy and tumors.

Concentrically circular echo planar spectroscopic imaging at 3T and 7T with partial temporal interleaving
Neil Wilson1, Hari Hariharan1, M. Albert Thomas2, and Ravinder Reddy1
1Radiology, University of Pennsylvania, Philadelphia, PA, United States, 2Radiology, University of California, Los Angeles, CA, United States
We use concentric circular echo planar k-space readout to spectroscopic sampling at high field. At high field, higher bandwidths are required which are difficult to achieve using echo planar techniques due to gradient limitations. Often temporal interleaving is employed to mitigate this. Circular k-space sampling is unique among the echo planar trajectories in that different rings can be sampled at different rates, requiring only partial temporal interleaving.

Rapid, High-Resolution 3D 1H-MRSI of the Brain based on FID Acquisitions
Mohammed Azeem Sheikh1, Fan Lam2, Chao Ma2, Bryan Clifford3, and Zhi-Pei Liang3
1Physics, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 2Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 3Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States
In 1H-MRSI, data is typically acquired with spin echo sequences with relatively long acquisition delay, often motivated by the need for water, lipid, and baseline suppression. Here, we present a new method to obtain high-resolution 1H-MRSI data with an FID-based acquisition that has a very short acquisition delay, enabled by a new scheme for nuisance signal removal. The new acquisition method enables short repetition time and rapid acquisition of spectroscopic data. Experimental results demonstrate in vivo 3D 1H-MRSI of the brain with isotropic 3 mm resolution in 15 minutes.

A comparison of lipid suppression by double inversion recovery, L1- and L2-regularisation for high resolution MRSI in the brain at 7 T
Gilbert Hangel1, Bernhard Strasser1, Michal Považan1, Martin Gajdošík1, Stephan Gruber1, Marek Chmelík1, Siegfried Trattnig1,2, and Wolfgang Bogner1
1MRCE, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria, 2Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria
Reliable lipid suppression is essential for robust quantification of parallel imaging accelerated high- resolution MRSI. This work compared the performance of non-selective lipid suppression using double inversion recovery (DIR) with the application of L1- and L2-regularisation during data processing for single-slice MRSI with a 64×64 matrix and a GRAPPA-acceleration of nine in five volunteers. While DIR featured the best lipid suppression, it increased the measurement time and reduced metabolite SNR. L1 and L2 did not have these downsides, but twice as much lipid signal remained, with L1 increasing the data pre-processing time before spectral quantification by a factor of six.

Crusher coil lipid suppression for volumetric 1H echo-planar spectroscopic imaging of the human brain at 7 Tesla
Karim Snoussi1,2, Joseph S. Gillen1,2, Michael Schär1,2, Vincent O. Boer3, Richard A.E. Edden1,2, and Peter B. Barker1,2
1Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2Kennedy Krieger Institute, Baltimore, MD, United States,3Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands
Suppression of extra cranial lipid signals is a significant challenge for MR spectroscopy at high field. This study describes the use of a crusher coil in a volumetric proton echo-planar spectroscopic imaging (EPSI) sequence for 7T. It is shown in vivo that the application of the crusher coil improves the spin-echo 7T EPSI sequence and allows to record high quality spectroscopic imaging data with extended 3D coverage and low RF power deposition.

Achieving High Spatiotemporal Resolution for 1H-MRSI of the Brain
Fan Lam1, Chao Ma1, Qiegen Liu1, Bryan Clifford1,2, and Zhi-Pei Liang1,2
1Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 2Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States
We present a novel strategy to achieve high spatiotemporal resolution for 1H-MRSI of the brain. The proposed acquisition scheme is characterized by: (a) the use of EPSI-based rapid spatiospectral encoding with an extended k-space coverage; (b) sparse sampling of (k,t)-space; (c) time-interleaved k-space undersampling, and (d) acquisition and use of navigator signals for determining subspace structures. This special acquisition is enabled by a subspace-based data processing and reconstruction method that can effectively remove nuisance signals and obtain high-quality reconstructions from sparse and noisy data. Experimental data have been acquired to demonstrate the potential of the proposed method in producing time-resolved spatiospectral distributions.

Measurement reproducibility of the spiral encoding GABA-edited MEGA-LASER 3D-MRSI in the brain at 3T
Petra Hnilicová1, Michal Považan2, Bernhard Strasser2, Ovidiu C Andronesi3, Dušan Dobrota1, Siegfried Trattnig2, and Wolfgang Bogner2
1Department of Medical Biochemistry, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia, 2Department of Biomedical Imaging and Image-guided Therapy, MR Center of Excellence, Medical University of Vienna, Vienna, Austria, 3Department of Radiology, Martinos Center for Biomedical Imaging, Harvard Medical School, Boston, MA, United States
In vivo assessment of neurotransmitter levels can improve the understanding of several pathological processes. For non-invasive GABA+ and Glx mapping in vivo within one scan, we applied a spiral-encoded GABA-edited MEGA-LASER 3D-MRSI sequence with real time corrections, achieving the ~3 cc nominal resolution in ~20 minutes. Via test-retest assessment in 14 healthy volunteers (7 men/7 women) we confirmed the measurement reproducibility and inter- and intra-subject variability of GABA+ and Glx ratios and thus validated that our method may be used in (pre)clinical studies of neurotransmitters alterations in the brain at 3T.  

Comparison of high-resolution FID-MRSI in the brain between 3 and 7 Tesla
Eva Heckova1, Stephan Gruber1, Bernhard Strasser1, Michal Povazan1, Gilbert Hangel1, Siegfried Trattnig1,2, and Wolfgang Bogner1
1High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria, 2Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria
Magnetic resonance spectroscopic imaging (MRSI) allows to measure different metabolites in the brain. SNR and spectral resolution increases at higher magnetic fields. We compared FID-MRSI with ultra short acquisition delay (1.5 ms) and a very high spatial resolution in the same group of healthy subjects at 3T and 7T. We found 1.87-fold increased SNR and decreased CRLBs at 7T in comparison with 3T. The higher spectral resolution at 7T allows to distinguish between NAA and NAAG and reliable detect other metabolites like Glx or Tau. Accelerating the acquisition techniques leads to lower SNR, however not to substantially decreased quantification precision.

Fast and efficient free induction decay MRSI at 9.4 T: assessment of neuronal activation-related changes in the human brain biochemistry
Grzegorz L. Chadzynski1,2, Jonas Bause2, G. Shajan2, Rolf Pohmann2, Klaus Scheffler1,2, and Philipp Ehses1,2
1Biomedical Magnetic Resonance, Eberhard-Karls University of Tübingen, Tübingen, Germany, 2High-field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
The aim was to design a MRSI-FID sequence for ultra-high field applications with high acquisition speed and sampling efficiency. The sequence allows acquisition of a 32×32 voxel matrix within approximately 2 min, down to 30 sec using parallel imaging. We have examined the suitability of this approach for assessing biochemical changes in the human visual cortex during a visual stimulus. Obtained results were in accordance with other functional MRS studies and indicate that the developed sequence is suitable for rapid monitoring of stimulus evoked changes in human brain biochemistry at a very high spatial resolution.

Quantitative Comparison of SNR between High and Low Resolution of 3D Chemical Shift Imaging (CSI)
Byeong-Yeul Lee1, Xiao-Hong Zhu1, and Wei Chen1
1Center for Magnetic Resonance Research, Radiology, University of Minnesota, Minneapolis, MN, United States
Spatial averaging of multiple high-resolution CSI (hrCSI) voxels is commonly employed to gain SNR and improve quantification of metabolites. Using in vivo 17-oxygen 3D CSI, we compared SNR between spatial averaging of multiple hrCSI voxels and a single voxel acquired with low-resolution CSI (lrCSI) with matched sample volume and position. SNR from voxel averaging was much lower than that of lrCSI caused mainly by the increased noise level by spectral summation. This study clearly demonstrates that the acquisition of high-resolution data with spatial averaging faces a large trade-off of SNR. Therefore, it should be taken consideration carefully for the choice of an appropriate voxel size of high-resolution CSI for in vivo study of neurological or metabolic diseases. 

Removal of Nuisance Signal from Sparsely Sampled 1H-MRSI Data Using Physics-based Spectral Bases
Qiang Ning1,2, Chao Ma2, Fan Lam2, Bryan Clifford1,2, and Zhi-Pei Liang1,2
1Electrical and Computer Engineering, University of Illinois, Urbana-Champaign, Urbana, IL, United States, 2Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana-Champaign, Urbana, IL, United States
A novel nuisance removal method is proposed for 1H-MRSI. The method uses spectral bases generated for water and subcutaneous lipids using quantum simulation, and can perform nuisance signal removal directly from (k,t)-space data. Consequently, the proposed method is able to handle sparsely sampled MRSI data, which provides a desirable flexibility for designing accelerated 1H-MRSI data acquisition schemes.  Experimental results demonstrate that the proposed method is capable of removing nuisance signals from 1H-MRSI data acquired from the brain without water and lipid suppression pulses.

Neurochemical Changes in Thalamus and Midbrain of Patients with Obstructive Sleep Apnea Syndrome using Accelerated Echo Planer J-resolved Spectroscopic Imaging
Manoj Kumar Sarma1, Paul Michael Macey2, Rajakumar Nagarajan1, Ravi Aysola3, and M. Albert Thomas1
1Radiological Sciences, UCLA School of Medicine, Los angeles, Los Angeles, CA, United States, 2School of Nursing, UCLA School of Medicine, Los angeles, Los Angeles, CA, United States, 3Division of Pulmonary and Critical Care Medicine, UCLA School of Medicine, Los angeles, Los Angeles, CA, United States
Obstructive sleep apnea syndrome (OSAS), which have many comorbidities including hypertension and other cardiovascular diseases, leads to autonomic, cognitive, and affective abnormalities. The thalamus, and midbrain are key structures that serve such functions through critical relays in nuclei but the status of this region is unclear OSAS. Here, we examined neurochemical changes in the thalamus and midbrain of OSAS patients to better understand the nature of tissue changes using compressed sensing based 4D echo-planar J-resolved spectroscopic imaging (EP-JRESI) and prior knowledge fitting (ProFit) algorithm for metabolite quantification. We observed significantly increased mI/Cr in midbrain and bilateral thalamus. Significantly increased Glx/Cr, Glu/Cr was found in right thalamus and midbrain, and decreased tNAA/Cr, NAA/Cr in left thalamus and midbrain respectively. Thalamus showed significantly reduced tCho/Cr bilaterally. We also found significantly decreased GPC/Cr, increased Gln/Cr, Asc/Cr in right thalamus and increased Asc/Cr in midbrain. The findings will help to explain structural brain changes in OSAS. Most of these metabolites can be manipulated through pharmacological approaches, and could serve as a biomarker of any possible intervention.

Prior Knowledge Fitting (ProFit) of Non-uniformly Sampled 5D Echo Planar Spectroscopic Imaging Data : Effect of Acceleration on Concentrations and  Cramer Rao Lower Bounds
Zohaib Iqbal1 and M. Albert Thomas1
1Radiological Sciences, University of California - Los Angeles, Los Angeles, CA, United States
The five dimensional echo planar spectroscopic imaging (5D EP-JRESI) sequence uses an echo planar readout, non-uniform sampling (NUS), and compressed sensing reconstruction to obtain two dimensional spectra from three spatial dimensions. However, the effects of NUS and reconstruction on quantitation results and fit quality parameters, such as the Cramer Rao Lower Bound (CRLB), are unknown. This study uses the new Prior knowledge Fitting (ProFit) algorithm to fit the 5D EP-JRESI results acquired using retrospective as well as prospective NUS. Comparison to the full data demonstrates that the 5D EP-JRESI method can sample 8-times faster while retaining accurate metabolite ratios and CRLB values.      

Ultrashort TE 3D spectroscopic imaging for high SNR imaging and bi-exponential signal decay characterization of sodium
Jetse S. van Gorp1, Paul W. de Bruin2, and Peter R. Seevinck1
1Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands, 2Radiology, Leiden University Medical Center, Leiden, Netherlands

Sodium relaxation behavior has been related to structural and cellular integrity, which is of interest for early disease detection. However, the short T2* values, bi-exponential relaxation behavior and low sensitivity makes accurate signal characterization challenging. In this work a 3D-UTE-FID-SI sequence was developed to measure the sodium decay curve with a 32kHz temporal resolution and sub-ms TE to characterize the bi-exponential signal decay characteristics of sodium in vitro and in vivo.

Accounting for GABA editing efficiency and macromolecule co-editing to allow inter-vendor comparisons of GABA+ measurements
Ashley D Harris1,2,3,4,5, Nicolaas AJ Puts1,5, Laura Rowland6, S. Andrea Wijtenburg6, Mark Mikkelsen7, Peter B Barker1,5, C. John Evans7, and Richard AE Edden1,5
1FM Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 2CAIR Program, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada,3Radiology, University of Calgary, Calgary, AB, Canada, 4Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Calgary, AB, Canada, 5Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, Baltimore, MD, United States, 6Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, United States,7CUBRIC, School of Psychology, Cardiff University, Cardiff, United Kingdom
Differences in GABA+ MEGA PRESS acquisitions between vendors are quantified in terms of the editing efficiency of GABA and the fractional co-editing of macromolecules. Accounting for these two parameters results in moderate agreement among the different vendors considered.

Towards a neurochemical profile of the amygdala using SPECIAL at 3 tesla
Florian Schubert1, Ralf Mekle1, Simone Kühn2, Jürgen Gallinat3, and Bernd Ittermann1
1Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany, 2MPI for Human Development, Berlin, Germany, 3Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
Since disturbed amygdala function is linked to psychiatric conditions insight into its biochemistry, particularly the neurotransmitters, is required. We combined the SPECIAL MRS sequence with FAST(EST)MAP implementation, corrections for frequency drift, relaxation, CSF volume, and a basis set including a measured macromolecule spectrum for quantification of metabolites in the amygdala in 20 volunteers at 3T. Beyond quantification of the three main metabolites plus myo-inositol with excellent precision, for the first time glutamate was determined reliably and separately from glutamine. Using a basis set without macromolecules introduced a systematic overestimation of concentrations. Glutamine and glutathione was quantifiable only in a subset of spectra.

Estimation of  in vivo ?-aminobutyric acid (GABA) levels in the neonatal brain
Moyoko Tomiyasu1,2, Noriko Aida3, Jun Shibasaki4, Katsutoshi Murata5, Keith Heberlein6, Mark A. Brown7, Eiji Shimizu2, Hiroshi Tsuji1, and Takayuki Obata1
1National Institute of Radiological Sciences, Chiba, Japan, 2Chiba University, Chiba, Japan, 3Department of Radiology, Kanagawa Children's Medical Center, Yokohama, Japan, 4Kanagawa Children's Medical Center, Yokohama, Japan, 5Siemens, Tokyo, Japan, 6Biomedical Imaging Technology Center, Burlington, MA, United States, 7University of Colorado, Cary, NC, United States
We examined in vivo brain γ-aminobutyric acid (GABA) levels of neonates and compared them with those of children. In this study, 32 normal neonates and 12 normal children (controls) had their brain GABA levels measured using clinical 3T edited-MRS. The neonates exhibited significantly lower GABA+ levels than the children in both the basal ganglia and cerebellum, which is consistent with previous in vitro data. While significantly higher GABA+/Cr levels were detected in the neonatal cerebellum, care should be taken when comparing GABA+/Cr levels between different ages. This is the first report about the in vivo brain GABA levels of neonates.

Assessment of Lipid Changes in Obese Calf Using Muti-Echo Echo-planar Correlated Spectroscopic Imaging
Rajakumar Nagarajan1, Raissa Souza1, Edward Xu1, Manoj K Sarma1, S. Sendhil Velan2, Cathy C Lee3, Theodore Hahn3, Catherine Carpenter4, Vay-Liang Go5, and M.Albert Thomas1
1Radiological Sciences, University of California Los Angeles, Los Angeles, CA, United States, 2Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, Singapore, Singapore, 3Geriatrics, VA Greater Los Angeles Healthcare System, Los Angeles, CA, United States, 4UCLA Schools of Nursing, Medicine, and Public Health, Los Angeles, CA, United States, 5UCLA Department of Medicine, Los Angeles, CA, United States
Obesity is a serious public health problem associated with high rates of morbidity and mortality. One-dimensional MR spectroscopy suffers from overlapping spectral resonances which can complicate metabolite identification and quantitation. Two-dimensional spectroscopic techniques have been demonstrated in calf muscle to reduce the problem of spectral overlap. In this study, we used the four dimensional (4D) multi-echo echo planar correlated spectroscopic imaging (ME-EPCOSI) technique to quantify the lipids and metabolites in soleus, tibialis anterior and gastrocnemius calf muscles of obese and normal healthy subjects. The 4D ME-EPCOSI acquired data enabled less ambiguous quantitation of metabolites, unsaturated and saturated fatty acids in different calf muscle regions using IMCL ratios and unsaturation indices.

Simultaneous modeling of spectra and apparent diffusion coefficients.
Victor Adalid Lopez1, André Doering1, Sreenath Pruthviraj Kyathanahally 1, Christine S. Bolliger1, and Roland Kreis1
1Depts. Radiology and Clinical Research, University Bern, Bern, Switzerland
Diffusion weighted spectroscopy can provide information on the diffusion of metabolites and the microstructure of brain tissue. A method for simultaneous fitting of spectra related by mono-exponential diffusion weighting is introduced, which is similar to simultaneous fitting of a 2DJ or inversion recovery data set. As shown for simulated white matter data, the method improves both, accuracy and precision of ADC estimation for all metabolites. It is also illustrated with diffusion data obtained from human gray matter at 3T.

Novel Triple-refocusing 1H MRS at 3T for detection of GABA in human brain in vivo
Zhongxu An1, Sandeep Ganji1, Vivek Tiwari1, and Changho Choi1
1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States
Reliable detection of GABA is important for research studies in neuro-psychiatric diseases.  In vivo 1H GABA resonances extensively overlap with the neighboring resonances of glutamate and glutamine. We present an optimized single-shot triple-focusing 1H MRS method which fully resolved GABA 2.29-ppm signal at 3T. 

Prospective frequency correction for TE-averaged semi-LASER
Chu-Yu Lee1, In-Young Choi1,2,3, Peter Adany1, and Phil Lee1,3
1Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas city, KS, United States, 2Department of Neurology, University of Kansas Medical Center, Kansas City, KS, United States, 3Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, United States
Frequency drifts during MRS acquisition results in broad and distorted spectral lineshapes, a reduced SNR and quantification errors. The consequence of frequency drifts is particularly significant in spectral-editing sequences, because spectral editing critically relies on narrow-band frequency selective pulses or accurate spectral alignments among scans for subtraction/addition of spectra. Frequency drift can occur due to subject’s movement and/or MR system instability. Even in advanced MR systems with self-shielded gradients, significant frequency drifts occur due to eddy current-induced heating and cooling of passive shim materials, particularly after MR scans with heavy gradient duty cycles. The effects of frequency drifts can be mitigated through prospective and retrospective frequency corrections.  Currently, most spectral-editing methods use post-processing approaches to correct the effects of frequency drifts retrospectively. In this study, we have developed a prospective frequency correction method and implemented it in a semi-LASER based TE-averaged sequence for glutamate detection.

Automatic Multi-layer Classification System of Brain Tumor Based on Multi-modality MRI and Clinical Information
Yafei Wang1, Yue Zhang1, Lingyi Xu1, Yu Sun1, Lei Xiang2, Meiping Ye2, Suiren Wan1, Bing Zhang2, and Bin Zhu2
1The Laboratory for Medical Electronics, School of Biological Sciences and Medical Engineering, Southeast University, Nanjing, China, People's Republic of, 2Department of Radiology, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, China, People's Republic of
Classification or grading of brain tumor alone would not be enough for clinical use, therefore we designed a comprehensive multi-layer system combining the two functions together. Firstly, we designed it as a three-layer system according to clinic workflow. Then, we extracted new features from multi-modality MRI and patients’ clinical information, which were easily ignored or difficult found by eyes. And then we implemented SVM and Tumor Model to classify tumor type and tumor grade. This study proposed a novel multi-layer system for clinic use by reducing the diagnosis uncertainty.

Reproducibility and gender-related effects on macromolecule suppressed GABA and Glx metabolites
Muhammad Gulamabbas Saleh1, A Alhamud1, Jamie Near2, Frances Robertson1, André J.W. van der Kouwe3, and Ernesta M Meintjes1
1Human Biology, MRC/UCT Medical Imaging Research Unit, University of Cape Town, Cape Town, South Africa, 2Douglas Mental Health University Institute and Department of Psychiatry, McGill University, Montreal, QC, Canada, 3Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States
Several studies have characterized short and long term reproducibility of Glx and GABA+, but not macromolecule (MM) suppressed GABA. Further, gender-related differences have been observed in GABA+, but these may, in part, be due to inter-individual variations of MM. Motion and magnetic field inhomogeneity can hamper the consistent application of frequency-selective pulses at 1.7ppm necessary for effective GABA editing.  We demonstrate that the shim and motion-navigated MEGA-SPECIAL sequence produces well-edited GABA and Glx spectra. LCModel quantification yields the best reproducibility. Observed gender-related differences in GABA highlight the need for gender-matching in studies investigating differences in GABA concentrations.

1H-MRS of Human Liver at 3 T: Relaxation Times and Metabolite Concentrations
Jan Weis1, Fredrik Rosqvist2, Joel Kullberg1, Ulf Risérius2, and Håkan Ahlström1
1Department of Radiology, Uppsala University, Uppsala, Sweden, 2Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
Proton MR spectroscopy of healthy human liver was performed at 3 T MR scanner. The purpose of this study was to estimate glycogen (Glycg), choline-containing compounds (CCC), water, and lipid (-CH2-)nrelaxation times T1, T2, and absolute concentration of Glycg, CCC, and fat. Experiments were performed using multiple breath-hold technique. Spectra were processed by LCModel. T1 and T2 values were obtained by mono-exponential fitting spectral intensities versus repetition or echo times. Quantification of liver Glycg, CCC and lipids is important for understanding changes in lipid and glucose metabolism due to metabolic disorders. 

Gradient-heavy sequences degrade the quality of subsequent spectroscopy acquisitions
Benjamin C Rowland1, Fatah Adan1, Huijun Liao1, and Alexander P Lin1
1Centre for Clinical Spectroscopy, Brigham and Women's Hospital, Boston, MA, United States
B0 frequency drift is a well-known phenomenon which can have a significant impact on MR spectroscopy, affecting both peak resolution and metabolite quantification. B0 drift is particularly associated with gradient-heavy EPI sequences like DTI. In a study of 53 subjects receiving DTI and MRS, the mean FWHM more than doubled as a result of frequency drift and metabolite concentrations were often misestimated by LC Model.

Elucidation of the downfield spectrum of human brain at 7T using multiple inversion recovery delays and echo times
Nicole D Fichtner1,2, Anke Henning2,3, Niklaus Zoelch2, Chris Boesch1, and Roland Kreis1
1Depts. Radiology and Clinical Research, University of Bern, Bern, Switzerland, 2Institute for Biomedical Engineering, UZH and ETH Zurich, Zurich, Switzerland, 3Max Planck Institute for Biological Cybernetics, Tuebingen, Germany
Characterization of the full 1H spectrum may allow for better monitoring of pathologies and metabolism in humans. The downfield part (5-10ppm) is currently less well characterized than upfield; this work aims to benefit from higher field strength in order to quantify T1 and T2 in the downfield spectrum in human grey matter at 7T. We fitted downfield spectra to a heuristic model and obtained relaxation times for twelve peaks of interest. The T1’s are higher than those at 3T downfield; peaks with lower T1’s may include macromolecules. The T2’s are mostly shorter than those reported for upfield peaks at 7T.

Tissue correction strategy impacts GABA quantification: a study in healthy aging
Ashley D Harris1,2,3,4, Eric Porges5, Adam J Woods5,6, Damon G Lamb5,7, Ronald A Cohen5, John B Williamson5,8, Nicolaas AJ Puts3,4, and Richard AE Edden3,4
1Radiology, University of Calgary, Calgary, AB, Canada, 2CAIR Program, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Calgary, AB, Canada, 3Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, Baltimore, MD, United States, 4FM Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 5Center for Cognitive Aging and Memory (CAM), McKnight Brain Institute, Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, United States, 6Department of Neuroscience, University of Florida, Gainesville, FL, United States, 7Brain Rehabilitation and Research Center, Malcom Randall Veterans Affairs Medical Center, Gainesville, FL, United States, 8Brain Rehabilitation and Research Center, Brain Rehabilitation and Research Center, Gainesville, FL, United States
There are various strategies for tissue correction for MRS. Here, using data from a healthy aging cohort, we show that the selection of tissue correction method can change the conclusions that are drawn from data.

Towards low power EPR Imaging using Frank poly-phase pulse sequence
Nallathamby Devasahayam1, Randall H. Pursley2, Thomas J. Pohida2, Shingo Matsumoto3, Keita Saito4, Sankaran Subramanian5, and Murali C. Krishna4
1Radiation Biology Branch, National Cancer Institute, Bethesda, MD, United States, 2Center for Information Technology, Bethesda, MD, United States, 3Graduate School of Information Science and Technology, Sapporo, Japan, 4National Cancer Institute, Bethesda, MD, United States, 5Indian Institute of Technology Madras, Chennai, India
Electron Paramagnetic Resonance (EPR) imaging  is suited well for small animal physiological imaging with its unique capability of generating in vivo quantitative oxygen maps. The main bottleneck in scaling up pulsed EPR imaging to human anatomy is that the required RF power of US federal food and drug administration (FDA), specific absorption rate (SAR) limits. In Frank Sequence we are using power levels on the order of 250 microwatts in a crossed coil resonator with ~35 dB isolation. Using a 256 pulse polyphase Frank Sequence, it was possible to obtain images with good SNR.

Hitchhikers guide to voxel segmentation for partial volume correction of in-vivo magnetic resonance spectroscopy
Scott Quadrelli1,2, Carolyn Mountford3, and Saadallah Ramadan2
1Queensland University of Technology, Brisbane, Australia, 2The University of Newcastle, Newcastle, Australia, 3The Translational Research Institute, Brisbane, Australia
Whilst many studies have detailed the impact of partial volume effects on proton magnetic resonance spectroscopy quantification, there is a paucity of literature explaining how voxel segmentation can be achieved using freely available neuroimaging packages. Here we aim to demonstrate a practical guide to magnetic resonance spectroscopy (MRS) voxel segmentation, partial volume correction and detail how to extract other MR metrics (such as DTI, fMRI) from a MRS voxel. 

Enhancement of signal intensity using a wireless coil for FT-EPR oximetry study
Ayano Enomoto1, Gadisetti V. R. Chandramouli2, Alan P Koretsky3, Chunqi Qian4, Murali K Cherukuri1, and Nallathamby Devasahayam1
1Radiation Biology Branch, National Cancer Institute, Bethesda, MD, United States, 2GenEpria Consulting Inc., Columbia, MD, United States, 3National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States, 4Department of Radiology, Michigan State university, East Lansing, MI, United States
Sensitivity enhancement is required to detect the weak signals with Fourier transform Electron Paramagnetic Resonance (FT-EPR).  In the proposed method, a small amount of sample was placed at a distance less than half the diameter of the receiving surface coil. The signal was enhanced by a wirelessly pumped coil. Presently, we used the TCNQ for our studies to study signal enhancement. Here, we achieved 7-fold of improvement in signal intensity in compared with conventional FT-EPR acquisition. We will show the results of in vivo oximetry using oxygen sensing solids LiPc and LiNc in in vivo applications to measure tissue oxygenation.

Assessment of serine quantification reproducibility using advanced 1H-MRS in the human brain at 3T
Homa Javadzadeh1,2 and Jean Théberge1,2,3
1Department of Medical Biophysics, University of Western Ontario, London, ON, Canada, 2Imaging Division, Lawson Health Research Institute, London, ON, Canada, 3Diagnostic Imaging Department, St. Joseph's Health Care, London, ON, Canada
D-serine supplements alleviate some of the most debilitating features of schizophrenia believed to be associated with glutamatergic abnormalities. Assessment of endogenous serine is impossible using standard proton Magnetic Resonance Spectroscopy (1H-MRS). This work employs a novel?1H-MRS sequence called DANTE-PRESS (D-PRESS) and presents test-retest reliability study for serine levels acquired at 3T in phantoms and initial data in two human subjects. We conclude that reproducibility and precision of serine measurements on a 3.0T scanner is sufficient to assess endogenous levels in vivo and is a valuable tool to examine abnormalities in schizophrenia and monitor supplementation.

Large Improvements of RF field Transmission Efficiency and Detection Sensitivity for Ultrahigh-field In vivo 31P MRS using Emerging Technology of Ultrahigh Dielectric Constant Material
Byeong-Yeul Lee1, Xiao-Hong Zhu1, Sebastian Rupprecht2, Michael T. Lanagan3, Qing X. Yang2,4, and Wei Chen1
1Center for Magnetic Resonance Research, Radiology, University of Minnesota, Minneapolis, MN, United States, 2Center for NMR Research, Radiology, The Pennsylvania State College of Medicine, Hershey, PA, United States, 3Engineering Science and Mechanics, The Pennsylvania State College of Engineering, University Park, PA, United States, 4Neurosurgery, The Pennsylvania State College of Medicine, Hershey, PA, United States
Compared to 1H MRS, X-nuclei MRS for human application faces two challenges: higher requirement of RF power (thus, higher SAR) for achieving the same RF pulse flip angle due to a relatively lower gyromagnetic ratio, and still limited SNR even at high/ultrahigh field. In this report, we demonstrate that up to 200% SNR gain was achieved with ultra high dielectric constant (uHDC) materials incorporated into the RF volume coil for 31P MRS at 7T. Concomitantly, the RF power optimized for acquiring the spectra was significantly reduced by 200%. Our data demonstrated that incorporating uHDC with RF coil can significantly boost SNR and reduce RF transmission power X-nuclei MRS applications on top of using high field strength magnet that has approached to its technologic limits.

9.4 Tesla 1H-MRS of Glutamate and GABA in a 3.6 cubic-mm volume using an optimized UTE-STEAM sequence
Nicola Bertolino1, Paul Polak1, Marilena Preda1,2, Robert Zivadinov1,2, and Ferdinand Schweser1,2
1Buffalo Neuroimaging Analysis Center, Department of Neurology,Jacobs School of Medicine and Biomedical Sciences, The State University of New York at Buffalo, Buffalo, NY, United States, 2MRI Molecular and Translational Research Center, Jacobs School of Medicine and Biomedical Sciences, The State University of New York at Buffalo, Buffalo, NY, United States
In-vivo 1H-MR spectroscopy is a non-invasive technique able to detect metabolites providing important information from investigated tissue. GABA and Glutamate are two metabolites altered in many neurological diseases, although challenging to quantify in vivo because of a number of technical issues: voxel localization, low concentration, short T2, overlapping peaks and spin-spin coupling. In this work we developed an optimized parameter set for an ultra-short TE STEAM.

Effects of Storage Conditions on Transverse Relaxation in Bovine Articular Cartilage
Kyle W. Sexton1, Hasan Celik1, Kenneth W. Fishbein1, and Richard G. Spencer1
1National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
Quantification of cartilage matrix components with nuclear magnetic resonance has potential applications to the early diagnosis of osteoarthritis. Ex-vivo cartilage samples are often used to observe the MR parameters of healthy and degraded cartilage. To ensure the accuracy of MR parameters, the storage of the explants is extremely important. DPBS is often used to immerse cartilage tissue specimens during imaging, with the assumption that it prevents dehydration. In this study it was found that storing BAC tissue explants in DPBS can rapidly and significantly increase the observed T2 values. An alternative storage medium to maintain T2 stability is Fluorinert.

Frequency correction based on interleaved water acquisition improves spectral quality in MM-suppressed GABA measurements in vivo
Nicolaas AJ Puts1,2, Kimberly L Chan1, Ashley D Harris1,2,3,4, Peter B Barker1,2, and Richard AE Edden1,2
1Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States, 2F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 3Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada, 4Radiology, University of Calgary, Calgary, AB, Canada
MM-suppressed GABA measurements use symmetric editing of both MM and GABA signals. Frequency drift, either by gradient induced heating/cooling, or motion, significantly affects the editing efficiency of GABA and MM. To stabilize the center frequency, we interleaved the unsuppressed water acquisition throughout the scan and used it to correct the frequency, in eight healthy participants, and compared this to a condition without frequency correction. Frequency correction improves spectral quality of MM-suppressed GABA editing in vivo.

Single volume localization without RF refocusing for dynamic hyperpolarized 13C MR spectroscopy
Albert P Chen1, Ralph E Hurd2, Angus Z Lau3, and Charles H Cunningham4,5
1GE Healthcare, Toronto, ON, Canada, 2GE Healthcare, Menlo Park, CA, United States, 3Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom, 4Physical Sciences, Sunnybrook Health Sciences Centre, Toronto, ON, Canada, 5Medical Biophysics, University of Toronto, Toronto, ON, Canada
A method for single volume dynamic hyperpolarized 13C MRS acquisition is proposed.  Using a slice selective pulse-acquire pulse sequence with 2D spiral readout this technique enables 3D localization of the MRS data.  By confining the readout trajectory to each dwell time, the raw data sampled during the trajectory are averaged by the digital filter, thus the output data represent only the center voxel and no k-space data sorting and reconstruction are required.  This sequence can be used practically the same way as a standard pulse-acquire acquisition for HP13C experiments, but the spectrum will be localized to a 3D volume. 

Metabolic ratios can increase or decrease sample size requirements and statistical significance in magnetic resonance spectroscopy
Sarah E. Hoch1, Ivan I. Kirov2, and Assaf Tal3
1Radiology, Sheba Medical Center, Ramat-Gan, Israel, 2Radiology, New York University Langone Medical Center, New York, NY, United States, 3Chemical Physics, Weizmann Institute of Science, Rehovot, Israel
Metabolite ratios are often used to simplify metabolic quantification. It is often implicitly assumed that they are also statistically favorable when both numerator and denominator metabolites change in opposing manners. Herein, we show that even for such cases, both sample size requirements and statistical significance depend non-trivially on taking the ratio. We conclude that care must be taken when deciding between ratios and absolute quantification during study design. 

Improved semi-LASER sequence with short echo time for ultra-high field using selective GOIA refocusing pulses
Michal Považan1,2, Lukas Hingerl1, Bernhard Strasser1, Gilbert Hangel1, Eva Heckova1, Stephan Gruber1, Siegfried Trattnig1,2, and Wolfgang Bogner1
1High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University Vienna, Vienna, Austria, 2Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria
MR spectroscopy (MRS) profits from ultra-high field (UHF) with higher SNR and enhanced spectral resolution. However, the higher demand on bandwidth of RF pulses together with power limitations complicate the utilization of localization sequences such as PRESS or STEAM. A semi-LASER sequence appears to be a suitable candidate for UHF MRS if properly optimized. We aimed to implement selective GOIA refocusing pulses and optimize the gradient scheme to yield shortest echo time possible on a volume coil. Our semi-LASER sequence outperformed the conventional sequences in terms of SNR and chemical shift displacement artifact and proved to be applicable at UHF.

Assessment of intracellular lipids of non-adipose pancreatic cells
Jan Weis1, Lina Carlblom1, Lars Johansson1, Olle Korsgren2, and Håkan Ahlström1
1Department of Radiology, Uppsala University, Uppsala, Sweden, 2Department of Immunology, Genetics and Pathology, Uppslala University, Uppsala, Sweden
A 1.5 T clinical scanner was used for proton MR spectroscopy (1H-MRS) of human pancreas allografts. The main purpose was to estimate intracellular lipid content in non-adipose pancreatic cells. The secondary aim was to quantify total fat and choline-containing compounds. Spectrum processing was performed in the time domain using MRUI software package. It was demonstrated that 1H-MRS is an effective method for non-invasive estimation of intracellular lipid content in non-adipose pancreatic cells. This knowledge could be helpful in studies of various aspects of β-cell function (insulin production).      

Assessment and retrospective correction of rotation-induced signal attenuation in diffusion-weighted spectroscopy
Michael Dacko1, Benjamin Knowles1, Patrick Hucker1, Maxim Zaitsev1, and Thomas Lange1
1Medical Physics, University Medical Center Freiburg, Freiburg, Germany
Diffusion-weighted spectroscopy of the brain is a highly motion-sensitive MR method as a consequence of the large voxel size and low metabolite diffusion coefficients. In this work, we correct for voxel displacement during DWS experiments with prospective motion correction and investigate the signal attenuation due to rotation-induced intra-voxel dephasing.  Phantom experiments with 'synthetic' rotations confirmed the theoretically predicted signal attenuation. High correlation between rotational motion and attenuation of the residual water peak was observed in vivo. Retrospective rejection criteria based on the recorded motion tracking data and on the residual water peak amplitude are compared.


Fast automatic voxel positioning with non-rigid registrations for improved between-subject consistency in MRS
Young Woo Park1, Dinesh K. Deelchand2, James M. Joers2, Brian J. Soher3, Peter B. Barker4, HyunWook Park1, Gülin Öz2, and Christophe Lenglet2
1School of Electrical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Korea, Republic of, 2Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota Medical School, Minneapolis, MN, United States, 3Department of Radiology, Duke University Medical Center, Durham, NC, United States, 4Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
During the typical acquisition of single-voxel Magnetic Resonance Spectroscopy (MRS) the corresponding voxel-of-interest (VOI) must be selected manually, which induces some degree of variability. To address this, several automated VOI positioning methods, using rigid registration and aimed at follow-up scans of the same subject, have been proposed. This approach can be generalized to cross-subject scans, but with additional considerations for the anatomical variability. We hypothesized that non-rigid registration methods will minimize inter-subject variability in the tissue content of the VOI. Here, we present an analysis of registration strategies aimed at a reliable cross-subject automatic VOI positioning for MRS data acquisition.

MM-suppressed GABA measurements are highly susceptible to B0 field instability
Richard Anthony Edward Edden1,2, Ashley D. Harris1,2,3,4, Nicolaas Puts1,2, Kimberly L. Chan1,2,5, Michael Schar1, and Peter B. Barker1,2
1Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, Baltimore, MD, United States, 2F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 3Department of Radiology, University of Calgary, Calgary, AB, Canada, 4Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Calgary, AB, Canada, 5Department of Biomedical Engineering, The Johns Hopkins University, Baltimore, MD, United States
J-difference-edited measurements of GABA are usually contaminated up to 50% by macromolecular (MM) signal.  It is possible to suppress this signal using a symmetrical editing motif, which relies upon partially inverting the MM signals to an equal degree in the two halves of the edited experiment.  In the event of B0  field offset, the symmetry breaks down and either positive or negative MM signal rapidly contaminates the measured GABA signal.  Here, we investigate this issue using simulations and in vivo experiments.

HERMES: Hadamard Encoding and Reconstruction of MEGA-Edited Spectroscopy
Kimberly L Chan1,2,3, Nicolaas AJ Puts2,3, Peter B Barker2,3, and Richard AE Edden2,3
1Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, United States, 2Radiology and Radiological Science, Johns Hopkins School of Medicine, Baltimore, MD, United States, 3F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
Hadamard Encoding and Reconstruction of MEGA-Edited Spectroscopy, HERMES, is a novel method of the simultaneous, separable detection of overlapping metabolite signals. Classic J-difference editing involves the acquisition of two subspectra, with editing pulses applied to the target molecule (ON) or not (OFF).  HERMES edits multiple metabolites simultaneously by acquiring all combinations of OFF/ON for each (i.e. four experiments to edit two metabolites) and uses a Hadamard-like addition-subtraction reconstruction to generate separate edited spectra for each target metabolite.  In this abstract, we describe the method and demonstrate its application to NAA/NAAG editing, using simulations, and phantom and in vivo experiments.

Resolving Choline from Taurine in In-Vivo Magnetic Resonance Spectra at 9.4 T
Marissa E. Fisher1, Brennen J. Dobberthien1, Anthony G. Tessier1,2, and Atiyah Yahya1,2
1Department of Oncology, University of Alberta, Edmonton, AB, Canada, 2Department of Medical Physics, Cross Cancer Institute, Edmonton, AB, Canada
The Cho peak at 3.2 ppm contains significant signal contamination from the taurine (Tau) resonance in rat and mouse brain spectra, even at the high field strength of 9.4 T.  The purpose of this work it to optimise TE1and TE2 (echo times) of a Point RESolved Spectroscopy (PRESS) sequence to minimize Tau signal in the Cho spectral region at 9.4 T by exploiting the J-coupling evolution of the Tau protons.  The determined optimal {TE1, TE2} combination was found to be {25 ms, 50 ms}.  The efficacy of the timings was verified on rat brain in vivo.   

Diffusion weighted MR spectroscopy without water suppression allows to use water as inherent reference signal to correct for motion-related signal drop
André Döring1, Victor Adalid Lopez1, Vaclav Brandejsky1, Roland Kreis1, and Chris Boesch1
1Depts. Radiology and Clinical Research, University Bern, Bern, Switzerland
A non-water suppressed diffusion-weighting MR spectroscopy sequence based on metabolite-cycling and STEAM is presented and tested in-vitro and in-vivo.  The water peak as an inherent reference facilitates a post processing correction of the signal drop induced in individual acquisitions by cardiac and other motion. The correction leads to improved spectral resolution on one hand, but more importantly also to more accurate fitting of ADC values that are found to be smaller than without correction and most likely closer to the true values - and hence better suited for physiological interpretation.

Sustained GABA reduction induced by anodal Transcranial Direct Current Stimulation (tDCS) in motor cortex: A Proton Magnetic Resonance Spectroscopy Study
Harshal Jayeshkumar Patel1, Sandro Romanzetti2,3, Antonello Pellicano1, Kathrin Reetz2,3, and Ferdinand Binkofski1,4
1Division of Clinical Cognitive Sciences, Department of Neurology, RWTH Aachen University Hospital, Aachen, Germany, 2Department of Neurology, RWTH Aachen University Hospital, Aachen, Germany, 3Jülich Aachen Research Alliance (JARA) — Translational Brain Medicine, Aachen and Jülich, Germany, 4Research Center Jülich GmbH, Institute of Neuroscience and Medicine, Jülich, Germany
Transcranial direct current stimulation (tDCS) modulates cortical excitability. In this study we investigated long term effects of anodal stimulation on inhibitory neurotransmitter concentration using proton magnetic resonance spectroscopy (MRS). Our results indicates that excitatory tDCS cause locally reduction in GABA and it remains in decreased state over a period of 60 minutes presumably due to the decrease of activity of glutamic acid decarboxylase(GAD)67.

In Vivo Detection of Omega-3 Fatty Acids at 7 T with MEGA-sLASER
Lukas Hingerl1, Martin Gajdošík1, Michal Považan1, Bernhard Strasser1, Gilbert Hangel1, Martin Krššák1, Siegfried Trattnig1,2, and Wolfgang Bogner1
1High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria, 2Christian Doppler Laboratory for Clinical Molecular MR Imaging, Medical University of Vienna, Vienna, Austria
We present a method for detecting omega-3 fatty acids (FA) at 7 T by 1H-MR spectroscopy (MRS) using a MEGA-sLASER editing sequence with 12 kHz AFP GOIA-WURST(16,4) pulses for localization. sLASER localization offers reduced sensitivity to B1 inhomogeneities, lowers pulse power requirements compared to PRESS or STEAM and the localization pulses substantially reduce the 4-compartment effect. The spectra of in vivo measurements at the echo times TE=332 ms ,465.4 ms and 1130 ms show the omega-3 signal very well.

Cerebral Acetate Transport and Utilization in the Rat Brain in vivo using 1H MRS: Consequences of a revised acetate volume of distribution value
Masoumeh Dehghani M.1, Bernard Lanz1, Nicolas Kunz2, Pascal mieville3, and Rolf Gruetter1,2,4,5
1Laboratoire d'imagerie fonctionnelle et métabolique(LIFMET), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, 2Centre d’Imagerie Biomedicale(CIBM), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, 3Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, 4Department of Radiology, University of Lausanne, Lausanne, Switzerland, 5Department of Radiology, University of Geneva, Geneva, Switzerland
Metabolic modeling of metabolite 13C turnover curves in brain with 13C-labeled acetate infused as tracer substrate requires prior knowledge of the transport and uptake kinetics of Ace. The aim of this study was to determine the kinetics of transport and utilization for acetate uptake in the rat brain using specific distribution volume of Ace(Vd) in the rat brain. The dependency of estimated CMRace to distribution volume of Ace in the rat brain highlights the importance about a refined determination of Vd for Ace in brain metabolic studies.

Interleaved measurements of BOLD response and energy metabolism in exercising human calf muscle
Adrianus J. Bakermans1, Chang Ho Wessel2, Paul F.C. Groot1, Erik S.G. Stroes2, and Aart J. Nederveen1
1Department of Radiology, Academic Medical Center, Amsterdam, Netherlands, 2Department of Vascular Medicine, Academic Medical Center, Amsterdam, Netherlands
Typically, dynamic MR studies of exercising skeletal muscle are limited to measurements of only one parameter. Obtaining multiple parameters simultaneously during a single experiment would provide more insight into (patho-)physiology. Here, we report on interleaved acquisitions of quantitative T2* maps for assessments of the BOLD response, and 31P-MR spectra for measuring phosphocreatine recovery kinetics during an exercise-recovery protocol in healthy subjects and peripheral artery disease (PAD) patients. We demonstrate that with such interleaved acquisitions, it is feasible to dynamically assess both tissue oxygenation as well as muscle energy metabolism in the human calf muscle during a single exercise session.

Artificial intelligence for high-resolution nuclear MRS under inhomogeneous magnetic fields
Qiu Wenqi1, Wei Zhiliang1, Ye Qimiao1, Chen Youhe2, Lin Yulan1, and Chen Zhong1
1Department of Electronic Engineering, Xiamen University, Xiamen, China, People's Republic of, 2Department of Mechanical and Electrical Engineering, Xiamen University, Xiamen, China, People's Republic of
High-resolution multi-dimensional nuclear magnetic resonance (NMR) spectroscopy serves as an irreplaceable and versatile tool in various chemical investigations. In this study, a method based on the concept of partial homogeneity is developed to offer two-dimensional (2D) high-resolution NMR spectra under inhomogeneous fields. Oscillating gradients are exerted to encode the high-resolution information, and a field-inhomogeneity correction algorithm based on pattern recognition is designed to recover high-resolution spectra. The proposed method improves performances of 2D NMR spectroscopy under inhomogeneous fields without increasing the experimental duration or significant loss in sensitivity, and thus may open important perspectives for studies of inhomogeneous chemical systems.

2D Relaxometry and Diffusivity of Human Knee Synovial Fluid after ACL-injuries Studied Using HR-MAS NMR
Kaipin Xu1, Subramaniam Sukumar1, John Kurhanewicz1, and Xiaojuan Li1
1Radiology, University of California, San Francisco, San Francisco, CA, United States
To better understand the pathological progression of osteoarthritis (OA), techniques based on high resolution magic angle spinning (HR-MAS) NMR spectroscopy are developed for the study of relaxation times (T1, T2, and T1ρ) and diffusion coefficient (D) of human knee synovial fluids (SF) harvested from 1 OA and 8 anterior cruciate ligament (ACL) injured patients.

Towards fast and highly localized spectroscopy using miniaturized coils in a 14.1T animal scanner
Marlon Arturo Pérez Rodas1,2, Jörn Engelmann1, Hellmut Merkle1, Rolf Pohmann1, and Klaus Scheffler1,3
1Ultra High-field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany, 2Graduate Training Centre of Neuroscience, IMPRS for Cognitive and Systems Neuroscience, University of Tübingen, Tübingen, Germany, 3Department for Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany
The distinction of functional activity between cortical layers in the brain by MRI or MRS requires high spatial and temporal resolution. High spatial resolution can be achieved by increasing the gradient strength or by using the intrinsic volume selectivity of miniature coils, even in conventional animal scanner. In the present work, initial results for highly-localized spectroscopy within seconds are presented, for a phantom metabolite solution and cell cultures in a 14.1T animal scanner using a 2mm-diameter circular coil. The larger signals from the major metabolites in ~1.5µL were detected in 24sec on the phantom solution with an acceptable SNR.

DRESS localized FAST technique at 7T uncovers the relation between mitochondrial capacity and ATP synthase flux in exercising gastrocnemius medialis muscle
Marjeta Tušek Jelenc1,2, Marek Chmelík1,2, Barbara Ukropcová3,4, Wolfgang Bogner1,2, Siegfried Trattnig1,2, Jozef Ukropec4, Martin Krššák1,2,5, and Ladislav Valkovic1,2,6,7
1High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria, 2Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria,3Institute of pathophysiology, Faculty of Medicine, Comenius University, Bratislava, Slovakia, 4Obesity section, Diabetes and Metabolic Disease Laboratory, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia, 5Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria, 6Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia, 7University of Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
The aim of the study was to investigate the relation between the maximum oxidative flux (Qmax), a valid measure of muscular mitochondrial capacity and ATP synthase flux (FATP) measured in exercising gastrocnemius medialis muscle in healthy young and elderly subjects. Furthermore, we explored the possibility of direct measurement of both, Qmax and FATP_ex, in a single experiment. The dynamic experiment consisted of the acquisition of baseline data during two minutes of rest, six minutes of aerobic plantar flexion exercise (during which a 3.5 minutes long FAST measurement was performed), and six minutes of recovery. Our data showed significant correlation between ATP synthase flux in exercising muscle and maximal oxidative flux.

Metabolomic characterization of ovarian tumors by ex vivo magnetic resonance spectroscopy
Feng-Hua Ma1, Jin-Wei Qiang2, Guo-Fu Zhang1, Ya-Min Rao3, Hai-Min Li4, and Song-Qi Cai4
1Department of Radiology, Obstetrics & Gynecology Hospital, Shanghai Medical College,Fudan University., Shanghai, China, People's Republic of, 2Department of Radiology, Jinshan Hospital, Shanghai Medical College,Fudan University, Shanghai, China, People's Republic of, 3Department of Radiology, Obstetrics& Gynecology Hospital, Shanghai Medical College, Fudan University, Shanghai, China, People's Republic of,4Department of Radiology, Jinshan Hospital, Shanghai Medical College, Fudan University, Shanghai, China, People's Republic of
Coherent results obtained by ex vivo and in vivo measurements allow the translation of biomarker findings from studies of tissue specimens (ex vivo) to those of patients (in vivo), and therefore it is important to establish how well correlated these metabolic profiles are. Such correlation has been evaluated for brain tumors, prostate cancer and cervical cancer, but without comparison of ovarian tumors. In this study we try to investigate the relationship between the Cho/Cr from in vivo MRS and the Cho/TSP of ex vivo MRS from tissue samples and the potential to bridge molecular and imaging diagnostics.

Neurochemical profiles of the rat forepaw cortex during electrical and laser light stimulations measured with proton MR spectroscopy
Nathalie Just1, Lydia Wachsmuth1, Florian Schmid1, and Cornelius Faber1
1Translational Imaging Centre, University of Münster, Münster, Germany
Optogenetics is a more and more recognized technique for investigating neuronal populations in the rodent brain. Combined to fMRI (OfMRI), more understanding could be achieved. However, the effects of powerful light on the tissue remain poorly understood. Here, experiments were conducted to investigate the effects of blue laser light  on  the metabolism of the primary somatosensory cortex.

AAV serotype 9 vector transducing the human alpha-L-iduronidase gene normalizes hippocampal and cerebellar neurochemical profiles in a mouse model of mucopolysaccharidosis type I
Ivan Tkac1, Igor Nestrasil2, R Scott McIvor3, Kelley Kitto4, Carolyn A Fairbanks4, Karen Kozarsky5, Walter C Low6, Chester B Whitley2, and Lalitha Belur3
1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 2Dept. of Pediatrics, University of Minnesota, Minneapolis, MN, United States, 3Dept. of Genetics and Cell Biology, University of Minnesota, Minneapolis, MN, United States, 4Dept. of Pharmaceutics, University of Minnesota, Minneapolis, MN, United States, 5REGENXBIO Inc., Rockville, MD, United States, 6Dept. of Surgery, University of Minnesota, Minneapolis, MN, United States
Mucopolysaccharidosis type I (MPS I) is a lysosomal storage disease caused by the deficiency in α-L-iduronidase (IDUA) enzyme which results in lysosomal accumulation of glycosaminoglycans. The purpose of this study was to assess the ability of the adeno-associated virus (AAV) - mediated IDUA gene therapy to prevent the pathological neurochemical changes associated with the MPS I disease. The efficacy of the gene therapy was assessed by in vivo 1H MRS at 9.4T using knockout mice deficient for IDUA, a well-established murine model of MPS I.

Region-specific Neurochemical profile differences in juvenile rat model for ADHD and control strain: a 1H MRS study @ 11.7T
Alireza Abaei1, Francesca Rizzo2, Dinesh K Deelchand3, Anne Subgang1, Johannes T. Schneider4, Andrea G. Ludolph5, and Volker Rasche1,6
1Medical Faculty, Core Facility Small Animal MRI, Ulm University, Ulm, Germany, 2Institute of Anatomy and Cell Biology, University of Ulm, Ulm, Germany, 3University of Minnesota, Minneapolis, MN, United States,4Bruker BioSpin MRI GmbH, Ettlingen, Germany, 5Department of Child and Adolescent Psychiatry, University of Ulm, Ulm, Germany, 6Department of Internal Medicine II, University Hospital Ulm, Ulm, Germany
Assessment and reliable quantification of brain metabolites is of great interest for diagnosis and monitoring of neurodegenerative psychiatric disorders. Challenging in this context is the required spectral fidelity demanding a combination of rapid data acquisition, optimal frequency and phase correction, and excellent shimming of the volume of interest. In this contribution, an optimized STEAM sequence was combined with image-based shimming and single-shot frequency and phase correction. The method was applied to assessment of the difference between the metabolic profile of spontaneous hypertensive rats and Wistar-Kyoto rats. Statistically significant differences could be quantified in the striatum and the prefrontal cortex.

Biochemical Characteristics in Amyotrophic Lateral Sclerosis Detected by 7T MR Spectroscopy
Nazem Atassi 1,2, Maosheng Xu3,4, Christina Triantafyllou5, Boris Keil 2,6, Christopher Long7, Robert Lawson 1,2, Paul Cernasov1,2, Elena Ratti1,2, Paganoni Sabrina1,2, Nouha Salibi8, Ravi Seethamraju9, Bruce Rosen2,3, Merit Cudkowicz1,2, and Eva-Maria Ratai2,3
1Neurology, Massachusetts General Hospital, Boston, MA, United States, 2A. A. Martinos Center for Biomedical Imaging, Charlestown, MA, United States, 3Radiology, Massachusetts General Hospital, Boston, MA, United States, 4Radiology, First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China, People's Republic of, 5Siemens Healthcare, Erlangen, Germany, 6Massachusetts General Hospital, Boston, MA, United States, 7MIT Sloan Neuroeconomics Lab, Cambridge, MA, United States, 8Siemens Healthcare, Auburn, AL, United States, 9Siemens Healthcare, Charlestown, MA, United States
The purpose of this study was to quantify brain metabolites in Amyotrophic Lateral Sclerosis (ALS) patients using 7-Tesla MR spectroscopy and investigate how these metabolites correlate with clinical outcomes.  Patients with ALS had significantly decreased N-acetylaspartate (NAA), glutamate (Glu) and GABA in the left motor cortex consistent with neuronal injury or loss.  NAA/Cr and glutathione/Cr correlated with the revised ALS Functional Rating Scale. Increased pathological reflexes, a clinical marker of upper motor neuron degeneration correlated positively with myo-Inositol/Cr and choline/Cr, and negatively with NAA/Cr.  7T MRS can provide effective biomarkers in ALS patients which correlate well with clinical outcomes.

Investigation of Glucose-phosphates in Skeletal Muscle Biopsies by 1H HR-MAS NMR: Comparison between Active and Sedentary Subjects
Gaëlle Diserens1, Martina Vermathen2, Nicholas T. Broskey3, Chris Boesch1, Francesca Amati1,3, and Peter Vermathen1
1Depts Clinical Research and Radiology, University of Bern, Bern, Switzerland, 2Dept. Chemistry & Biochemistry, University of Bern, Bern, Switzerland, 3Dept. of Physiology, University of Lausanne, Lausanne, Switzerland
The aim of this 1H HR-MAS NMR study was to investigate biopsies of skeletal muscles comparing athletes, sedentary slim and sedentary obese subjects. 1H HR-MAS allows the direct assessment of glucose-phosphates contained in skeletal muscle biopsies, as was also previously shown. The current study is the first example for a potential application, demonstrating differences in glucose-phosphates between muscle tissues from athletes and sedentary subjects. The results suggest that quantitative assessment by 1H HR-MAS NMR of Glc-1P and Glc-6P being key players in energy metabolism may prove important for metabolic studies in biopsies.

Intratumoral Agreement of HR-MAS MR spectroscopic profiles in the Metabolic Characterization of Breast Cancer
Vivian Youngjean Park1, Dahye Yoon2, Ja Seung Koo1, Eun-Kyung Kim3, Seung Il Kim4, Ji Soo Choi1, Suhkmann Kim5, and Min Jung Kim1
1Yonsei University College of Medicine, Seoul, Korea, Republic of, 22Department of Chemistry and Chemistry Institute for Functional Materials, Pusan National University, Busan, Korea, Republic of, 3Radiology, Yonsei University College of Medicine, Seoul, Korea, Republic of, 4Surgery, Yonsei University College of Medicine, Seoul, Korea, Republic of, 5Pusan National University, Busan, Korea, Republic of
We investigated whether intratumoral location and biospecimen type affect the metabolic characterization of breast cancer assessed by HR-MAS MR spectroscopy. This prospective study included 87 tumor tissue samples in 31 patients with invasive breast cancer, obtained from the center and periphery of surgical specimens and preoperatively by CNB. Specimens were assessed with HR-MAS MR spectroscopy. Overall, intratumoral location and biospecimen type had limited influence on the metabolic characterization of breast cancer assessed by HR-MAS MR spectroscopy. However, some metabolites are differentially expressed and caution is recommended in clinical decision-making based solely on metabolite concentrations, especially PC and PE. 

Proton MR Metabolic Profiling in combination with serum procalcitonin levels as rapid indicators for differentiation of Urosepsis
Suruchi Singh1, Tanushri Chatterji2, Manodeep Sen2, Ishwar Ram3, and Raja Roy1
1Centre of Biomedical Research, Lucknow, India, 2Department of Microbiology, Dr Ram Manohar Lohia Institute of Medical Sciences, Lucknow, India, 3Department of Urology, Dr Ram Manohar Lohia Institute of Medical Sciences, Lucknow, India
This study is a new approach for the diagnosis of Urosepsis using Proton MR spectroscopy along with serum procalcitonin levels. The study insights, NMR based metabolic profiling for differentiation of Urosepsis, a medical emergency which requires immediate patient care. The analysis takes less than one hour for disease identification, thus enabling quick and efficient patient management. The Principal Component Analysis (PCA) displayed that glucose and lactate in serum were the major confounders in differentiating Urosepsis cases from Healthy controls. The training set of Partial least square Discriminant analysis (PLS-DA) provided precise prediction of the test set in serum samples.

Chemosensory analysis of medicinal plants by NMR phytometabolomics
Rama Jayasundar1 and Somenath Ghatak1
1NMR, All India Institute of Medical Sciences, New Delhi, India
There is increasing interest in systems approach in healthcare, from clinical medicine, diet and nutrition, pharmacology to plant-based drug development. The potential of NMR to study medicinal plants as a whole to evaluate system parameters such as organoleptic properties have been explored in detail in this study. Since taste is a chemosensory effect, NMR has been used for this analysis of medicinal plants along with Electronic tongue based chemometrics for objective measurement of taste. The results indicate an active role for NMR in chemosensory research.

Magnetic resonance spectroscopy (MRS) of post-traumatic epileptogenesis
Amna Yasmin1, Olli Gröhn1, Asla Pitkänen1, and Riikka Immonen1
1Department of Neurobiology, A.I. Virtanen Institute University of Eastern Finland, Kuopio, Finland
Traumatic brain injury (TBI) is the main cause of mortality and morbidity worldwide. Up to 53 % of TBI patients with penetrating head injuries develop epilepsy in later part of life. Unavailability of biomarkers for epileptogensis is a major unmet clinical need, and is the greatest obstacle on the way of developing treatment in patients at risk, e.g., after TBI. Objective of this study is to determine metabolic profile in perilesional cortical area in clinically relevant TBI rat model and correlate MRS findings with EEG and histological outcomes in search for biomarkers. Results: Six out of 13 parameters showed changes at some follow point.  Findings of long TBI follow up will help to investigate cellular and molecular mechanisms underlying post-traumatic epileptogenesis and identify reliable biomarkers that could serve as therapeutic targets for the development of new antiepileptogenic and antiseizure compound.

Cervicovaginal fluid acetate, a marker for preterm birth in symptomatic pregnant women
Emmanuel Amabebe1, Steven Reynolds2, Victoria Stern1, Jennifer Parker3, Graham Stafford3, Martyn Paley2, and Dilly Anumba1
1Academic unit of Reproductive and Developmental Medicine, University of Sheffield, Sheffield, United Kingdom, 2Academic unit of Radiology, University of Sheffield, Sheffield, United Kingdom, 3School of Dentistry, University of Sheffield, Sheffield, United Kingdom
We characterized the metabolite profile of cervicovaginal fluid (CVF) of a cohort of pregnant women presenting with symptoms of preterm labor by both 1H Magnetic Resonance spectroscopy and spectrophotometric acetate enzyme assay. Acetate normalized integral (P=0.002) and spectrophotometry (P=0.006) were significantly higher in the women who delivered preterm compared to their term counterparts.  Both methods were predictive of PTB <37 weeks (acetate integral: AUC=0.75, spectrophotometry: AUC=0.74). Elevated CVF acetate in women with symptoms of preterm labor appears predictive of preterm delivery. In these women, a clinical assay of acetate in CVF may prove of clinical utility for predicting PTB.   

Proton MR Metabolic Profiling in Bodyfluids for differentiation of Meningitis in adults
Tanushri Chatterji1, Dr. Suruchi Singh2, Dr. Manodeep Sen1, Dr. Ajai Singh3, Prof. Raja Roy2, and Dr. J.K Srivastava4
1Microbiology, Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, India, 2Centre of Bio-Medical Research, Lucknow, India, 3Neurology, Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, India, 4Amity Institute of Biotechnology, Amity University, Lucknow, India
This study explored diagnostic utility based on the analysis of CSF, serum and urine for differential diagnosis of bacterial (BM) and tubercular meningitis (TBM) in adults using 1H NMR metabolic profiling.This may render rapid diagnosis of meningitis resulting to the decline of mortality by appropriate and timely treatment regimen. The Discriminant Functional Analysis (DFA) identified acetate, alanine, malonate and choline containing compounds as significant metabolites among case and control. The Orthogonal Signal Correction Principal Component Analysis (OSC-PCA) of significant metabolites clearly differentiated case vs control group in serum and urine samples, while a clear classification could not be obtained for CSF samples.

High Resolution 1H NMR-based Metabolomics study of Serum in Parkinson’s disease
Pawan Kumar1, Sadhana Kumari1, Senthil S Kumaran1, Shefali Chaudhary1, Vinay Goyal2, Madhuri Behari2, S N Dwivedi3, Achal Srivastava2, and Naranamangalam R Jagannathan1
1Department of NMR and MRI Facility, All India Institute of Medical Sciences, New Delhi, India, 2Department of Neurology, All India Institute of Medical Sciences, New Delhi, India, 3Department of Biostatistics, All India Institute of Medical Sciences, New Delhi, India
We used 1H NMR technique to investigate the serum samples of 6 patients with Parkinson’s disease (PD) and 6 healthy controls (HC) using 700 MHz NMR spectrometer and the data were processed using the Agilent software, Vnmrj2.3A. PLS-DA multivariate analysis was performed to explore biochemical dissimilarities between PD patients and HC using MetaboAnalyst (3.0) software. We observed significantly elevated levels of lactate, glutamate and methyl guanidine PD patients in comparison with HC on t-test, suggesting protein metabolism impairment, mitochondrial dysfunction and oxidative stress in PD patients.

A Proton Magnetic Resonance Study to Investigate Dietary Influences on Blood Plasma of patients with Celiac Disease
Uma Sharma1, Deepti Upadhyay1, Govind Makharia2, Prasenjit Das3, Siddharth Datta Gupta3, and Naranamangalam R Jagannathan1
1Department of NMR and MRI Facility, All India Institute of Medical Sciences, New Delhi, India, 2Department of Gastroenterology and human Nutrition, All India Institute of Medical Sciences, New Delhi, India,3Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
The present study demonstrated dietary induced variations on the metabolic profile of blood plasma of CeD patients. Increased valine was seen in CeD non-vegetarians compared to CeD vegetarians. Both CeD vegetarians and non-vegetarians showed increased concentrations of gluconeogenic amino acids like alanine and glycine compared to healthy subjects. Increased pyruvate and creatine in CeD vegetarians compared to healthy vegetarians indicates impaired energy supply. Decreased creatinine in CeD vegetarians and non-vegetarians compared to healthy subjects is due to protein malabsorption in CeD. The study illustrates the nutritional status of CeD patients and healthy subjects on the basis of their dietary intake.

NMR-based Metabolomic Study of Serum in Diabetic Retinopathy
Virendra Kumar1, Tanmoy Bagui2, Rashmi Mukherjee2, Vertika Rai2, Pawan Kumar1, and Chandan Chakraborty2
1Department of NMR, All India Institute of Medical Sciences, New Delhi, India, 2School of Medical Science & Technology, Indian Institute of Technology Kharagpur, Kharagpur, India
Diabetic retinopathy (DR), is a major cause of blindness, caused by prolonged diabetes. However, this morbidity is largely preventable and treatable. The progression of DR from prolonged diabetes involves complex metabolic de-regulations. 1H NMR-based metabolomics of serum have potential to study dysregulation in metabolites of DR patients. Results of the PCA and PLS-DA analysis revealed metabolic differences in DR patients compared to healthy subjects. Using such a study, we may observe the severity of disease based on metabolic fingerprints and it may serve as a platform for screening of molecular targets for a more efficient therapeutic intervention.

Acute Spinal Cord Injury (ASCI) Metabolomics Through 1H-NMR Spectroscopy: Metabolic alterations with time & treatment
Alka Singh1, Suruchi Singh2, Saloni Raj1, Ravindra Kumar Garg3, Abbas Ali Mahdi4, Raja Roy2, and Rajeshwar Nath Srivastava1
1Orthopaedic Surgery, King George's Medical University, Lucknow, India, 2Centre of Biomedical Research, Lucknow, India, 3Neurology, King George's Medical University, Lucknow, India, 4Biochemistry, King George's Medical University, Lucknow, India
It mainly focuses on finding significant metabolites in serum using 1H NMR based spectroscopic methods and to study the variation of concentration of these metabolites during the recovery of the patient ongoing treatment after surgery.  Significant metabolites, namely, lactate, glycine, acetone and succinate were identified using statistical methods (ANOVA along with Mann- Whitney U test) and are found to be elevated during the time of injury. The levels gradually decrease as the patient recovers in an average period of six months.This is a prospective case-control preliminary study on recovery of the patient during acute spinal cord injury.

Pathological glutamatergic neurotransmission in Gilles de la Tourette Syndrome
Ahmad Seif Kanaan1,2, Sarah Gerasch2, Isabel Garcia-Garcia1, Leonie Lampe1, André Pampel1, Alfred Anwander1, Jamie Near3, Kirsten Müller-Vahl2, and Harald E. Möller1
1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 2Department of Psychiatry, Hannover Medical School, Hannover, Germany, 3Douglas Mental Health University Institute and Department of Psychiatry, Mcgill University, Montreal, QC, Canada
We hypothesized that glutamatergic signalling is related to pathophysiology of Gilles de la Tourette syndrome (GTS) and investigated glutamatergic metabolism within cortico-striatal regions using 1H-MRS at baseline and during treatment. Absolute metabolite concentrations were calculated with the consideration of voxel compartmentation following frequency and phase drift correction in the time domain. GTS patients exhibited reductions in striatal and thalamic [Glx], which were normalized with treatment and were correlated with clinical severity parameters. Our results implicate glutamatergic metabolism in GTS pathophysiology and indicate a possibly dysfunctional astrocytic-neuronal coupling system, which would have profound effects on the dopaminergic modulation of cortico-striatal input.

Mona A Mohamed1, Peter B Barker1, Richard L Skolasky2, Heidi Vornbrock Roosa3, Yun Zhou1, Weiguo Ye1, Noble George1, James Brasic1, Dean F Wong1, and Ned Sacktor3
1Radiology, Johns Hopkins Medical Institutions, Baltimore, MD, United States, 2Orthopedics, Johns Hopkins Medical Institutions, Baltimore, MD, United States, 3Neurology, Johns Hopkins Medical Institutions, Baltimore, MD, United States
In this study, 7T MRS and 18F AV45 PET were used to measure brain metabolites and amyloid burden in Elderly HIV subjects. These reliable biomarkers can be used in assessing the relation between normal aging, HIV and the degree of HIV Associated Neurocognitive Disorders (HAND).

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