Measurement of glycine in human prefrontal brain by point-resolved spectroscopy at 7.0 tesla in vivo.
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.
Choi
Changho
C
Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA. changho.choi@utsouthwestern.edu
Douglas
Deborah
D
Hawesa
Halima
H
Jindal
Ashish
A
Storey
Charles
C
Dimitrov
Ivan
I
D000465:Algorithms; D005260:Female; D005998:Glycine / Q000032:analysis*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D017397:Prefrontal Cortex / Q000378:metabolism*; D014018:Tissue Distribution; D055815:Young Adult
D005998:Glycine