Measurement of glycine in the human brain by 1H-MRS at 3T

INTRODUCTION Glycine (Gly), an inhibitory neurotransmitter and co-agonist at the N-methyl-D-aspartate receptors, has a singlet resonance at 3.55 ppm. Because of its low concentration and the overlapping coupled resonances of myo-inositol (mIns) at much higher concentrations, precise measurement of Gly by H-MRS remains as a challenge. For intermediate field strengths, following the applications of 2D J-resolved PRESS (point-resolved spectroscopy) at 3T [1] and TE-averaging PRESS at 4T [2], a long-TE triple refocusing method was reported for 3T [3]. Recently, short-TE and optimized long-TE approaches were reported at 7T [4, 5]. Here, we report an optimized long-TE PRESS method for differentiation between Gly and mIns at 3T. Preliminary in vivo results from healthy volunteers are presented.