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In vivo chemical shift imaging of γ‐aminobutyric acid in the human brain
Author(s) -
Shen Jun,
Shungu Dikoma C.,
Rothman Douglas L.
Publication year - 1999
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/(sici)1522-2594(199901)41:1<35::aid-mrm7>3.0.co;2-c
Subject(s) - nuclear magnetic resonance , imaging phantom , creatine , magnetic resonance imaging , in vivo , aminobutyric acid , chemistry , flip angle , pulse sequence , physics , optics , biology , medicine , biochemistry , receptor , microbiology and biotechnology , radiology
A gradient‐based multiple quantum filtering method is presented for in vivo chemical shift imaging of γ‐aminobutyric acid (GABA) in the human brain, which provides effective suppression of the overlapping creatine singlet with close to optimal detection efficiency. It is shown by product operator calculations and coherence pathway analysis that under conditions of no B 1 and B 0 inhomogeneity gradient filtering retains 75% of the two outer resonance lines of the GABA‐4 triplet with no creatine contamination. A variation of the method with 100% retention of the GABA‐4 outer resonance lines but higher sensitivity to B 1 inhomogeneity is also discussed. By using a localized version of the sequence with an 8‐cm surface coil for transmission and detection, it was found in phantom experiments at 2.1 T that a 69% signal retention of the two outer resonance lines of the GABA‐4 triplet was achieved relative to a spin echo sequence with inhibition of GABA J modulation. A creatine suppression ratio of 2000:1 was measured. The use of the method for chemical shift imaging of GABA is demonstrated by coronal images obtained from phantoms and from the occipital lobe of a healthy volunteer. Magn Reson Med 41:35‐42, 1999. © 1999 Wiley‐Liss, Inc.