T2 measurement of J-coupled metabolites in the human brain at 3T.

ABSTRACT

Proton T(2) relaxation times of metabolites in the human brain were measured using point resolved spectroscopy at 3T in vivo. Four echo times (54, 112, 246 and 374 ms) were selected from numerical and phantom analyses for effective detection of the glutamate multiplet at ~ 2.35 ppm. In vivo data were obtained from medial and left occipital cortices of five healthy volunteers. The cortices contained predominantly gray and white matter, respectively. Spectra were analyzed with LCModel software using volume-localized calculated spectra of brain metabolites. The estimate of the signal strength vs. TE was fitted to a monoexponential function for estimation of apparent T(2) (T(2)(†)). T(2)(†) was estimated to be similar between the brain regions for creatine, choline, glutamate and myo-inositol, but significantly different for N-acetylaspartate singlet and multiplet. T(2)(†)s of glutamate and myo-inositol were measured as 181 ± 16 and 197 ± 14 ms (mean ± SD, N = 5) for medial occipital cortices, and 180 ± 12 and 196 ± 17 ms for left occipital cortices, respectively.