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Diurnal stability of γ‐aminobutyric acid concentration in visual and sensorimotor cortex
Author(s) -
Evans Christopher John,
McGonigle David John,
Edden Richard Anthony Edward
Publication year - 2010
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.21996
Subject(s) - visual cortex , precentral gyrus , reproducibility , neuroscience , functional magnetic resonance imaging , gamma aminobutyric acid , audiology , magnetic resonance imaging , nuclear magnetic resonance , chemistry , psychology , medicine , physics , receptor , radiology , chromatography
Purpose: To establish the diurnal stability of edited magnetic resonance spectroscopy measurements of gamma‐aminobutyric acid (GABA) in visual and sensorimotor regions of the brain. Materials and Methods: GABA measurements were made in two regions of the brain (an occipital, “visual” region and a “sensorimotor” region centered on the precentral gyrus) using the MEGA‐PRESS editing method, scanning eight healthy adults at five timepoints during a single day. GABA concentration was quantified from the ratio of the GABA integral to the unsuppressed water signal. Results: No significant effect of time on GABA concentration was seen ( P = 0.35). GABA was shown to be significantly more concentrated in visual regions than in sensorimotor regions (1.10 i.u. and 1.03 i.u., respectively; P = 0.050). Coefficients of variability (CVs) across all subjects of 9.1% and 12% (visual and sensorimotor) were significantly higher than mean within‐subjects CVs of 6.5% and 8.8. Conclusion: This study demonstrates the excellent reproducibility of MEGA‐PRESS detection of GABA, demonstrating that the method is sufficiently sensitive to detect inter‐subject variability, and suggests that (within the sensitivity limits of current measurements) time of day can be ignored in the design of MRS studies of visual and sensorimotor regions. J. Magn. Reson. Imaging 2010;31:204–209. © 2009 Wiley‐Liss, Inc.