1CMROI, Department of Radiology,
University of Pennsylvania, Philadelphia, PA, United States; 2Department
of Biology, Wake Forest University, Winston-Salem, NC, United States; 3Department
of Neurology, and Center for Functional Neuroimaging, University of
Pennsylvania, Philadelphia, PA, United States
Gamma-aminobutyric
acid (GABA) is the major inhibitory neurotransmitter of the brain and plays a
critical role in multiple central nervous system diseases. The objective of
this study was to characterize the chemical exchange saturation transfer
(CEST) effect of the -NH2 protons of GABA and to demonstrate GABA imaging in
the human brain at 7T. The Z-spectrum of GABA showed a pH sensitive asymmetry
around ~2.75 ppm downfield to the water resonance. CEST imaging of healthy
human volunteers clearly showed the distribution of GABA CEST contrast in
different regions of the brain with negligible contrast from cerebrospinal
fluid