Proton T 1 and T 2 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 (T1 and T2), glutamate at 2.35 ppm (T1), creatine at 3.03 and 3.92 ppm (T1 and T2), choline‐containing substances at 3.22 ppm (T1 and T2), myo‐inositol at 3.57 and 3.65 ppm (T1) and the overlapping signals of glutamate and glutamine at 3.75 ppm (T1). The T1 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, T2 relaxation times range from 116 to 247 ms and from 141 to 295 ms in grey and white matter, respectively. Generally, the T1 values measured at 3 T are close to the previously published data found at 1.5, 2 and 4.1 T. Also, the T2 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, currently tested for enhanced clinical applications. Copyright © 2001 John Wiley & Sons, Ltd.