Quantitative 1H-MRS of healthy human cortex, hippocampus, and thalamus: metabolite concentrations, quantification precision, and reproducibility.
OBJECTIVE
To evaluate metabolite concentrations in cortical gray matter, hippocampus, and thalamus of healthy adults, and to investigate precision and reproducibility of quantitative proton magnetic resonance spectroscopy (1H-MRS) in these gray matter regions.


METHODS
Quantitative single-voxel short echo-time spectra were obtained from healthy human cortex, hippocampus, and thalamus. Subjects were examined twice. Metabolite concentrations, quantification precision, and reproducibility were determined.


RESULTS
There were no significant differences between test and retest measurements. Regional differences were observed with respect to metabolite concentrations, quantification precision, and reproducibility. Quantification precision and reproducibility of N-acetylaspartate and N-acetyl aspartylglutamate (tNAA), creatine and phosphocreatine (tCr), choline-containing compounds (Cho), and myo-inositol (myo-Ins), were better than those of glutamate (Glu) and glutamine (Gln). Generally, precision and reproducibility were better in cortex than in hippocampus or thalamus. The quantification precision was shown to correlate both with reproducibility and spectral linewidth.


CONCLUSIONS
The reliability of quantitative MRS depends on the metabolite concerned, its concentration, and on the brain area studied. Moreover, the quantification precision of a metabolite in a single spectrum appears to be a reliable measure for its reproducibility in a longitudinal study.
Geurts
Jeroen J G
JJ
Department of Radiology, MR Center for MS Research, VU University Medical Center, Amsterdam, The Netherlands.
Barkhof
Frederik
F
Castelijns
Jonas A
JA
Uitdehaag
Bernard M J
BM
Polman
Chris H
CH
Pouwels
Petra J W
PJ
D000328:Adult; D000704:Analysis of Variance; D001923:Brain Chemistry; D002540:Cerebral Cortex / Q000378:metabolism*; D005260:Female; D006624:Hippocampus / Q000378:metabolism*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D018709:Statistics, Nonparametric; D013788:Thalamus / Q000378:metabolism*