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In vivo detection of GABA in human brain using a localized double‐quantum filter technique
Author(s) -
Keltner John R.,
Wald Lawrence L.,
Frederick Blaise De B.,
Renshaw Perry F.
Publication year - 1997
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910370312
Subject(s) - nuclear magnetic resonance , imaging phantom , in vivo , creatine , resonance (particle physics) , physics , choline , chemistry , optics , atomic physics , biology , biochemistry , microbiology and biotechnology
A proton MR spectral editing technique employing a spatially localized, double‐quantum filter (DQF) was used to measure γ‐aminobutyric acid (GABA) in the human brain at 1.5 T. The double‐quantum method provided robust, single‐shot suppression of uncoupled resonances from choline, creatine, and NAA and allowed detection of the γCH 2 GABA (3.0 ppm) resonance with 30% efficiency. Spatial localization of the GABA measurement was achieved by incorporating PRESS localization within the double‐quantum excitation and detection sequence. A calibration technique was developed to adjust the relative phases of the RF pulses to maximize the in vivo double‐quantum detection efficiency for an arbitrary voxel location. The sequence efficiency, degree of suppression of uncoupled resonances, and characterization of the in vivo DQF technique was examined in phantom experiments and in a study of the occipital lobe of 10 normal subjects. The ratio of the 3.0‐ppm GABA resonance to the 3.0‐ppm creatine resonance was found to be 0.20 ± 0.05 (SD).