Brain Glutamate Proton Transverse Relaxation Time as measured by Spectrally-Selective Refocusing
Choi C, Coupland N, Kalra S, Malykhin N, Bhardwaj P, Gheorghiu D, Allen P
University of Alberta
The proton NMR relaxation times T2 and T1 of glutamate (Glu) in the human brain in vivo, measured by a newly-developed spectrally-selective refocusing method, are reported. The apparent T2 of Glu was derived from fitting the C4-proton multiplet area values at six echo times, using both experimental data and density-matrix simulation. The T2 and T1 of Glu for the composite gray/white matter tissues were estimated, at 3 T, to be 168&[plusmn]11 ms and 1.23&[plusmn]0.08 s (mean&[plusmn]SD, n = 5) for the prefrontal cortex, and 163&[plusmn]14 ms and 1.22&[plusmn]0.05 s (n = 2) for the motor cortex, respectively.