ISMRM 23rd Annual Meeting & Exhibition • 30 May - 05 June 2015 • Toronto, Ontario, Canada

Scientific Session • New Methodological Approaches for MRS

Monday 1 June 2015

Room 701 B

16:30 - 18:30


Ovidiu C. Andronesi, M.D., Ph.D., Stefan Bluml, Ph.D.

16:30 0200.   Detection of cerebral NAD+ in humans at 7 T
Robin A. de Graaf1, Henk M. De Feyter1, Peter B. Brown1, Terence W. Nixon1, Douglas L. Rothman1, and Kevin L. Behar1
1MRRC, Yale University, New Haven, CT, United States

Nicotinamide adenine dinucleotide (NAD+) has a central role in cellular metabolism and energy production and is related to gene expression, calcium mobilization, aging, cell death and timing of metabolism via the circadian rhythm. The in vivo detection of NAD+ has traditionally been limited and has only recently been demonstrated on rat brain with 1H and 31P NMR spectroscopy. Here the detection of NAD+ by 1H NMR spectroscopy is extended to human brain at 7 T. Results are quantitatively compared to those obtained with in vivo 31P NMR spectroscopy.

16:42 0201.   GABA concentration in the superior temporal gyrus predicts gamma-band oscillations and multisensory perception - permission withheld
Ralf Mekle1, Johanna Balz2, Julian Keil2, Yadira Roa-Romero2, Semiha Aydin1, Florian Schubert1, Bernd Ittermann1, Juergen Gallinat3, and Daniel Senkowski2
1Medical Physics, Physikalisch-Technische Bundesanstalt, Berlin, Germany, 2Department of Psychiatry and Psychotherapy, Charité-Universitätsmedizin, Berlin, Germany, 3Department of Psychiatry and Psychotherapy, University Hospital Hamburg-Eppendorf, Hamburg, Germany

The integration of different sensory streams into a coherent, conscious percept is required for multisensory perception, where in human brain the superior temporal gyrus (STG) plays an important role. In this combined MRS-EEG study, the sound-induced flash illusion (SIFI) paradigm was applied to test the hypotheses that the GABA concentration in the STG predicts multisensory perception at the behavioral level and gamma-band activity during SIFI. MRS data were acquired using MEGA-PRESS at 3T, and EEG signals were recorded for 40 subjects. The hypotheses were confirmed, and a tight triangular relationship between GABA concentration, gamma-band oscillations, and multisensory perception was found.

16:54 0202.   
About differences of the transverse relaxation time (T2) of 18 brain metabolites in gray and white matter at 3T
Patrik Oliver Wyss1,2, Andreas Hock1,3, Milan Scheidegger1,3, Niklaus Zoelch1, Markus Rudin1,4, Spyros Kollias2, and Anke Henning1,5
1Institute for Biomedical Engineering, UZH and ETH Zurich, Zurich, Zurich, Switzerland, 2Institute of Neuroradiology, University Hospital Zurich, Zurich, Zurich, Switzerland, 3Department of Psychiatry, Psychotherapy and Psychosomatics Hospital of Psychiatry, University of Zurich, Zurich, Zurich, Switzerland, 4Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Zurich, Switzerland, 5Max Planck Institute for Biological Cybernetics, Tuebingen, Germany

The precise assessment of transverse relaxation time constant T2 of brain metabolites is a prerequisite for reporting quantitative MR spectroscopy results. To reveal differences of T2 in gray and white matter, echo time series data were recorded in 91 healthy volunteer at 3T and evaluated using ProFit2.0. Different T2relaxation times in gray and white matter exist for mi, cho, naa, glu and naag, which should be considered and precisely evaluated for. Differences may show changes in degrees of freedom and therefore may be used to reveal a variation of cell compartments or interaction between molecules and enzymes.

17:06 0203.   
A comparison of MEGA-sLASER and STEAM for in vivo quantification of GABA at 7T
Chen Chen1, Peter Morris1, Susan Francis1, and Penny Gowland1
1Sir Peter Mansfield Imaging Centre (SPMIC), University of Nottingham, Nottingham, Nottinghamshire, United Kingdom

GABA detection at 7T (B1,max=15uT) using an optimised long TE MEGA-sLASER spectral editing sequence was compared with a conventional short TE STEAM sequence in terms of 1) reproducibility and 2) measured [GABA]/[Cr+]. This study showed that 1) the intra-subject reproducibility of both methods was high (CV%=5-6%); 2) the inter-subject reproducibility of MM-corrected MEGA-sLASER was higher than STEAM, especially when the GABA concentration was low; 3) [GABA] ]/[Cr+] measured using both methods correlated well (r=0.69, p=0.006).

17:18 0204.   
Optimized Combination of Magnetic Resonance Spectroscopy Signal from Multi-Element Coil Arrays
Liang Fang1,2, Minjie Wu1, Hengyu Ke2, Anand Kumar1, and Shaolin Yang1,3
1Department of Psychiatry, University of Illinois at Chicago, Chicago, IL, United States, 2School of Electronic Information, Wuhan University, Wuhan, Hubei, China, 3Department of Radiology, University of Illinois at Chicago, Chicago, IL, United States

Multi-element coil arrays are commonly used in magnetic resonance imaging (MRI) for parallel imaging. However, how to combine the magnetic resonance spectroscopy (MRS) signal from a multi-element receiving coil array has been much less studied than imaging. In this study, we proposed a new method for theoretical optimal combination no matter the noise is correlated or uncorrelated among different coil elements. The validation experiments were performed with different voxel locations/sizes on a 3T MRI scanner with an 8-element head coil. The results verified the superior performance of the proposed method compared with the recently published and other routine combination methods.

17:30 0205.   
Improvement of 2-hydroxyglutarate detectability by optimized triple-refocusing at 3T in vivo
Zhongxu An1, Sandeep Ganji1, Elizabeth A. Maher1, Dianne Mendelsohn1, Marco Pinho1, Kevin Choe1, and Changho Choi1
1University of Texas Southwestern Medical Center, Dallas, Texas, United States

As a potential biomarker for clinical diagnosis and prognosis, in vivo 2HG detection in IDH mutated glioma patients with high specificity is important. Due to the extensively overlaps between 2HG signal at 2.25 ppm and GABA signal at 2.28 ppm, the estimation of 2HG is elusive when 2HG concentration is low (< 3mM). Here we present in vivo 2HG measurements without considerable GABA contamination achieved by 2HG optimized triple-refocusing at 3T.

17:42 0206.   
Assessment of hepatic glycogen turnover in mice by in vivo 13C-MRS
Andreas Boss1, Andor Veltien1, and Arend Heerschap1
1Radiology and Nuclear Medicine, Radboudumc, Nijmegen, Gelderland, Netherlands

We investigated the feasibility to assess hepatic glycogen turnover in mice by in vivo 13C-MRS. For this purpose, mice were infused with [1-13C]-labeled glucose (N=2), or galactose (N=3) for 120min, followed by 120min of infusion with the respective unlabeled substrate, while 13C-MR spectra of the liver were recorded throughout the experiment. Glycogen-signals increased in the first, and decreased in the second phase of all experiments indicating simultaneous synthesis and degradation. Turnover (rate of degradation/rate of synthesis) was determined from fitting the kinetics of glycogen to a metabolic model and was estimated to be ~84% with galactose as tracer substrate.

17:54 0207.   In Vivo Detection of 13C Labeling of Glutamate and Glutamine Using Proton MRS at 7T
Li An1, Shizhe Li1, Maria Ferraris Araneta1, Christopher Johnson1, James B Murdoch2, and Jun Shen1
1National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States, 2Toshiba Medical Research Institute USA, Mayfield Village, OH, United States

In vivo measurement of glutamate (Glu) and glutamine (Gln) turnover can provide valuable information on energy metabolism and neurotransmission in the human brain. Since 7 Tesla proton MRS has been shown to be capable of measuring dynamic changes in Glu and Gln signal strength during intravenously infusion of [U-13C6]glucose, in this work, we evaluated the feasibility of quantifying the time-courses of [4-13C]Glu and [4-13C]Gln concentrations measured by 7 Tesla 1H MRS. It was shown that the time-course difference spectra could be fitted very well using a linear combination of a numerically simulated basis set.

18:06 0208.   
Real-time tool to forecast the adequacy of shim and to define the number of acquisitions needed to answer the clinical question at hand with the prescribed 1H MR spectroscopy exam
Sreenath Pruthviraj Kyathanahally1 and Roland Kreis1
1Depts. Radiology and Clinical Research, University Bern, Bern, Switzerland

Presently, the spectral quality in 1H MRS can only be determined after performing the time-consuming part of the exam, i.e. the recording of the water-suppressed spectrum. In clinical routine, there is often no time to re-record a spectrum if it turns out to be of bad quality. Therefore, we have developed a tool to forecast the spectral quality and to judge the adequacy of the achieved shim and proposed number of scans using a single-shot non-water-suppressed spectrum. To test, we acquired in vivo brain spectra and compared the forecast with the actual errors found by LCModel and jMRUI-QUEST.

18:18 0209.   Kinetic Analysis of Dynamic Deuterium MR Spectra for Simultaneous Assessment of Cerebral Glucose Consumption Rate and TCA Cycle Flux - permission withheld
Ming Lu1, Xiao-Hong Zhu1, and Wei Chen1
1Center for Magnetic Resonance Research, University of Minnesota Medical School, Minneapolis, Minnesota, United States

Simultaneous assessment of cerebral glucose consumption rate (CMRglc) and TCA cycling rate (VTCA) is crucial for understanding neuroenergetics under various physiopathological conditions; nevertheless, such measurement was not possible. Recently, we developed a novel in vivo Deuterium (2H) MR (DMR) approach for noninvasively assessing glucose metabolisms in rat brain at 16.4 T. Following a brief injection of deuterated glucose, the dynamic labeling on glucose, glutamate/glutamine (Glx), water and lactate in the brain tissue can be monitored via tracking their well-resolved 2H signals. To quantify metabolic rates, a new kinetic model incorporating glycolysis, TCA cycle and lower case Greek alpha-ketoglutarate/Glx exchange was developed in this study. By least-square fitting of the model with the experimental data obtained from dynamic DMR measurement in rat brains, major metabolic fluxes such as CMRglc and VTCA can be determined concurrently. Two different metabolic conditions were examined; increased CMRglc (0.46 vs. 0.28 µmol/g/min) and VTCA (0.96 vs. 0.6 µmol/g/min) were found under morphine infusion as compare to the deeper anesthesia of 2% isoflurane, which are consistent with previous in vivo 13C or 1H MRS studies. In summary, we demonstrate that the new DMR approach in combine with the kinetic model described in this work is capable of simultaneously determining CMRglc and VTCA with high sensitivity and reliability.