Determining the in vivo transverse relaxation time of GABA in the human brain at 7T.

PURPOSE: To measure in vivo transverse relaxation times (T2 ) of gamma-aminobutyric acid (GABA) at 7T using the experimental spectral-editing method.
MATERIALS AND METHODS: Experiments were performed at 7T in a 10 mM GABA phantom to determine the intrinsic TE-dependence of the edited signal. Then the same method was applied with editing-based suppression of coedited macromolecular signals to five healthy volunteers to determine T2 of GABA in vivo.
RESULTS: From in vivo data acquired at multiple echo times, the in vivo GABA T2 relaxation time was estimated to be 63 ± 19 msec.
CONCLUSION: We present a measurement of the T2 of edited GABA signal at 7T by first using phantom measurements to determine the echo time-dependence of edited signal. The method is purely experimental and does not rely on prior knowledge of coupling constants or simulation of realistic experiments. J. Magn. Reson. Imaging 2013;38:1224-1229. © 2013 Wiley Periodicals, Inc.