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In vivo detection of brain glycine with echo‐time‐averaged 1 H magnetic resonance spectroscopy at 4.0 T
Author(s) -
Prescot Andrew P.,
Frederick Blaise deB,
Wang Liqun,
Brown John,
Jensen J. Eric,
Kaufman Marc J.,
Renshaw Perry F.
Publication year - 2006
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.20807
Subject(s) - nuclear magnetic resonance , glycine , nuclear magnetic resonance spectroscopy , in vivo , spectroscopy , echo (communications protocol) , spin echo , echo time , magnetic resonance imaging , resonance (particle physics) , chemistry , physics , biology , atomic physics , medicine , computer science , biochemistry , amino acid , microbiology and biotechnology , quantum mechanics , radiology , computer network
A single‐voxel proton magnetic resonance spectroscopy ( 1 H‐MRS) method is described that enables the in vivo measurement of endogenous brain glycine (Gly) levels in human subjects. At 4.0 T, TE‐averaging 1 H‐MRS dramatically attenuates the overlapping myo ‐inositol (mI) resonances at 3.52 ppm, permitting a more reliable measure of the Gly singlet peak. This methodology initially is described and tested in phantoms. The phantom data infers that the 3.55‐ppm peak predominantly is Gly with a smaller contribution from mI. The composite resonance thus is differentiated from pure Gly and mI and is labeled Gly*. The mI contribution was calculated as <2% of the total Gly* signal for a 1:1 mI/Gly mixture. The technique subsequently was used to acquire TE‐averaged 1 H‐MRS data from the occipital cortex of healthy control subjects. The resultant spectra closely resembled experimental phantom data. LC‐model analysis provided a means for quantifying TE‐averaged 1 H‐MRS spectra and a mean test–retest variability measure of 15% was established for brain Gly* levels in studies of six healthy subjects. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.