Measurement of brain glutamate using TE‐averaged PRESS at 3T

A method is introduced that provides improved in vivo spectroscopic measurements of glutamate (Glu), glutamine (Gln), choline (Cho), creatine (Cre), N‐acetyl compounds (NA tot , NAA + NAAG), and the inositols (mI and sI). It was found that at 3T, TE averaging, the f1 = 0 slice of a 2D J‐resolved spectrum, yielded unobstructed signals for Glu, Glu + Gln (Glx), mI, NA tot , Cre, and Cho. The C4 protons of Glu at 2.35 ppm, and the C2 protons of Glx at 3.75 ppm were well resolved and yielded reliable measures of Glu/Gln stasis. Apparent T 1 / T 2 values were obtained from the raw data, and metabolite tissue levels were determined relative to a readily available standard. A repeatibility error of <5%, and a coefficient of variation (CV) of <10% were observed for brain Glu levels in a study of six normal volunteers. Magn Reson Med 51:435–440, 2004. © 2004 Wiley‐Liss, Inc.