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Two‐dimensional, J‐resolved spectroscopic imaging of GABA at 4 Tesla in the human brain
Author(s) -
Jensen J. Eric,
Frederick Blaise deB.,
Wang Liqun,
Brown John,
Renshaw Perry F.
Publication year - 2005
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.20644
Subject(s) - nuclear magnetic resonance , macromolecule , creatine , magnetic resonance spectroscopic imaging , human brain , in vivo , imaging phantom , magnetic resonance imaging , chemistry , metabolite , nuclear magnetic resonance spectroscopy , voxel , resonance (particle physics) , pulse sequence , spectroscopy , nuclear medicine , physics , neuroscience , biochemistry , medicine , biology , atomic physics , radiology , microbiology and biotechnology , quantum mechanics
Abstract A method for measuring brain gamma‐amino butyric acid (GABA) levels is presented that combines 2D J‐resolved magnetic resonance spectroscopy (J‐MRS) techniques with chemical‐shift imaging (2D‐JMRSI) at 4 Tesla (T). The results of phantom and in vivo experiments agree well in demonstrating that the 2 CH 2 GABA resonance situated at 2.97 ppm can be resolved from the neighboring creatine (Cr) resonance at 3.03 ppm and quantified. Single‐voxel, J‐resolved standard and metabolite‐nulled in vivo experiments on six healthy subjects reveal a broad component from the underlying macromolecules (MM) that resonates at and around 3.00 ppm, which is estimated to contribute approximately 15% to the J‐resolved GABA resonance in this large voxel at a repetition time (TR) of 4.5 s. With our 2D‐JMSRI at 1.25 s TR, the macromolecule resonance contribution to our GABA measurements is approximated to be 12%. Six healthy human subjects underwent scanning at 4T with this sequence, yielding a global brain GABA concentration of 0.76 ± 0.20 mM after correction for 12% macromolecule contribution. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.