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Measurement of glycine in human prefrontal brain by point‐resolved spectroscopy at 7.0 tesla in vivo
Author(s) -
Choi Changho,
Douglas Deborah,
Hawesa Halima,
Jindal Ashish,
Storey Charles,
Dimitrov Ivan
Publication year - 2009
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.22125
Subject(s) - spectroscopy , glycine , chemistry , nuclear magnetic resonance , human brain , choline , creatine , inositol , standard deviation , in vivo magnetic resonance spectroscopy , nuclear magnetic resonance spectroscopy , in vivo , analytical chemistry (journal) , physics , magnetic resonance imaging , amino acid , mathematics , chromatography , biology , biochemistry , medicine , neuroscience , receptor , statistics , microbiology and biotechnology , radiology , quantum mechanics
Measurement of glycine in human frontal brain by an optimized point‐resolved spectroscopy sequence at 7 T is reported. Echo time dependencies of the overlapping coupled resonances of myo ‐inositol, free choline, and threonine were investigated with density matrix simulations, incorporating the slice‐selective radiofrequency and gradient pulses. The numerical simulations indicated that the selectivity of the 3.55‐ppm glycine singlet is maximized at (TE 1 , TE 2 ) = (101, 51) ms. Phantom experiments indicated that the myo ‐inositol peak amplitude between 3.5 and 3.6 ppm is reduced by a factor of 30 following the optimized point‐resolved spectroscopy, as predicted by the simulation. From LCModel analyses, the glycine concentration in the medial prefrontal cortex in healthy adults was estimated, with a mean Cramér‐Rao lower bound of 7 ± 1% (mean ± standard deviation; n = 7), to be 0.8 ± 0.1 mM, with reference to total creatine at 8 mM. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.