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Abstract #2397

Measurement of Glycine in Human Brain by PRESS at 7.0 Tesla in Vivo

Changho Choi1, Ivan Dimitrov1,2, Deborah Douglas1, Halima Hawesa1

1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA; 2Philips Medical Systems, Cleveland, OH, USA

Glycine (Gly) in human brain has been measured using an optimized PRESS (point-resolved spectroscopy) sequence at 7T. Echo time dependences of the coupled resonances of myo-inositol, choline and threonine were investigated for TE1 and TE2 between 20 and 200 ms with 1 ms increments, using the density matrix simulation incorporating the volume selective radio-frequency and gradient pulses. The numerical simulation indicated that the Gly selectivity is maximized at (TE1, TE2) = (100, 48) ms. LC model fitting was used for in vivo data analysis. The fit standard deviation of Gly was ≤ 8% in all three spectra (scan time ~5 min). The Gly concentration in human brain was estimated to be 0.6, 0.8 and 0.8 mM for the medial prefrontal, fronto-parietal and occipital cortices with reference to creatine at 8 mM, respectively.