Detection of glutathione in the human brain in vivo by means of double quantum coherence filtering

The feasibility of selective in vivo detection of glutathione (L-gamma-glut amyl-L-cysteinyl-glycine, GSH) in the human brain by means of H-1 magnetic resonance spectroscopy (MRS) at 1.5 T is demonstrated, A double quantum coh erence (DQC) filtering sequence was used in combination with PRESS volume s election. The strongly coupled cysteinyl CH2 compound of GSH was found to b e the most suitable target for spectral editing. Analytical calculations em ploying a product operator description of the cysteinyl ABX three-spin syst em were made in order to optimize the inherent yield of the sequence, A pul se phase calibration procedure, which precedes the spectrum acquisition, se cures maximal signal yield independently of the spatial localization of the volume of interest and thus comparability between individual examinations. In vitro tests show that the DQC filtering method provides good discrimina tion between the GSH signal at 2.9 ppm and the interfering resonances of cr eatine, gamma-aminobutyric acid (GABA) and aspartate, In measurements in th e frontal robe of 12 healthy volunteers a mean ratio of GSH signal to tissu e water signal of 5.7 +/- 2.3 x 10(-5) was found, corresponding to a mean G SH tissue concentration of 2-5 mmol/L, The proposed technique allows for th e detection of a biologically highly relevant metabolite at moderate field strength. Magn Reson Med 42:283-289, 1999. (C) 1999 Wiley-Liss, Inc.