In vivo 1H NMR measurement of glycine in rat brain at 9.4 T at short echo time.
Glycine is an amino acid present in mammalian brain, where it acts as an inhibitory and excitatory neurotransmitter. The two detectable protons of glycine give rise to a singlet at 3.55 ppm that overlaps with the more intense myo-inositol resonances, and its measurement has traditionally required specific editing efforts. The aim of the current study was to reduce the signal intensity of myo-inositol relative to that of glycine by exploiting the fast signal J-evolution of the myo-inositol spin system when using a single spin-echo localization method we recently introduced. Glycine was detected at TE = 20 ms with an average Cramér-Rao lower bound (CRLB) of 8.6% +/- 1.5% in rat brain (N = 5), at 9.4 T. The concentration of glycine was determined using LCModel analysis at 1.1 +/- 0.1 mM, in good agreement with biochemical measurements previously reported. We conclude that at high magnetic fields, glycine can be measured at a relatively short echo time (TE) without additional editing efforts.
Gambarota
Giulio
G
Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland. giulio.gambarota@epfl.ch
Xin
Lijing
L
Perazzolo
Chiara
C
Kohler
Ingrid
I
Mlynárik
Vladimír
V
Gruetter
Rolf
R
D000818:Animals; D001921:Brain / Q000378:metabolism*; D005998:Glycine / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
D005998:Glycine