Measurement of GABA and contaminants in gray and white matter in human brain in vivo.
A preliminary study of discrimination between GABA and macromolecules (MMs) in human brain by proton double quantum filtering (DQF) at 3.0 T in vivo is presented. GABA-tuned and MM-tuned DQ filters were designed with dual-band 180 degrees radiofrequency (RF) pulses that were tuned for selective refocusing of GABA (3.0 and 1.9 ppm) and putative MM resonances (3.0 and 1.7 ppm), respectively. GABA and putative MM signals were extracted from a combined analysis of the filtered mixture signals and the calculated editing yields. Unexpectedly, the GABA and putative MM signals exhibited a similar doublet linewidth at the optimized TE = 82 ms. Furthermore, substantial MM-tuned DQF signal remained at TE = 148 ms, indicating the presence of a component other than MM. With water segmentation data, the GABA-tuned and MM-tuned DQF measures from the medial prefrontal and left frontal lobes were combined to give the concentrations of GABA and the additional component as 1.1 +/- 0.1 and 0.8 +/- 0.1 mM (mean +/- SD, N=3) for gray matter (GM) and 0.4 +/- 0.1 and 0.7+/-0.1 mM (N=3) for white matter (WM), respectively.
Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada.
Changho
C
Choi
Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada.
Paramjit P
PP
Bhardwaj
Neurology Division, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.
Sanjay
S
Kalra
Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada.
Colin A
CA
Casault
Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada.
Umme S
US
Yasmin
Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada.
Peter S
PS
Allen
Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada.
Nicholas J
NJ
Coupland
D001923:Brain Chemistry; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D005680:gamma-Aminobutyric Acid / Q000032:analysis*
D005680:gamma-Aminobutyric Acid