A new single-voxel proton NMR spectrally-selective refocusing method for measuring glutamate (Glu) and glutamine (Gln) in the human brain in vivo at 3T is reported. Triple-resonance selective 180° RF pulses with a bandwidth of 12 Hz were implemented within point-resolved spectroscopy (PRESS) for selective detection of Glu or Gln, and simultaneous acquisition of creatine singlets for use as a reference in phase correction. The carriers of the spectrally-selective 180° pulses and the echo times (TEs) were optimized with both numerical and experimental analyses of the filtering performance, which enabled measurements of the target metabolites with negligible contamination from N-acetylaspartate and glutathione. The concentrations of Glu and Gln in the prefrontal cortex were estimated to be 9.7 ± 0.5 and 3.0 ± 0.7 mM (mean ± SD, N = 7), with reference to Cr at 8 mM.
- Human brain
- Prefrontal cortex
- RF pulse
- Spectrally-selective refocusing
- Triple-resonance selective 180°
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging