Proton T1 and T2 relaxation times of human brain metabolites at 3 Tesla

Longitudinal and transverse relaxation times were measured for proton MRS signals from human brain metabolites at 3 T using a short-echo STEAM protocol and a surface coil as a transmitter/receiver. Volumes of interest containing mostly grey or mostly white matter were selected in occipital lobes of healthy subjects and relaxation times for the following resonances were obtained: N-acetylaspartate at 2.01 ppm (T-1 and T-2), glutamate at 2.35 ppm (T-1), creatine at 3.03 and 3.92 ppm (T-1 and T2), choline-containing substances at 3.22 ppm (T-1 and T-2), myoinositol at 3.57 and 3.65 ppm (T-1) and the overlapping signals of glutamate and glutamine at 3.75 ppm (T-1). The T-1 relaxation times obtained range from 0.97 to 1.47 s for grey matter and from 0.87 to 1.35 s for white matter. On the other hand, T-2 relaxation times range from 116 to 247 ms and from 141 to 295 ms in grey and white matter, respectively. Generally, the T-1 values measured at 3 T are close to the previously published data found at 1.5, 2 and 4.1 T. Also, the T-2 values confirm the previously observed decrease in transverse relaxation times with increasing static magnetic field. The proton relaxation times obtained will allow improved sequence design and spectra quantitation at 3 T-1 currently tested for enhanced clinical applications. Copyright (C) 2001 John Wiley & Sons, Ltd.