REGIONAL METABOLITE CONCENTRATIONS IN HUMAN BRAIN AS DETERMINED BY QUANTITATIVE LOCALIZED PROTON MRS

The regional distribution of brain metabolites was studied in several cortical white and gray matter areas, cerebellum, and thalamus of youn g adults with use of quantitative single-voxel proton MRS at 2.0 T, Wh ereas the neuronal compound N-acetylaspartate is distributed homogeneo usly throughout the brain, N-acetylaspartylglutamate increases caudall y and exhibits higher concentrations in white matter than in gray matt er, Creatine, myo-inositol, glutamate, and glutamine are less concentr ated in cortical white matter than in gray matter. The highest creatin e levels are found in cerebellum, parallel to the distribution of crea tine kinase and energy-requiring processes in the brain, Also myo-inos itol has highest concentrations in the cerebellum. Choline-containing compounds exhibit a marked regional variability with again highest con centrations in cerebellum and lowest levels and a strong caudally decr easing gradient in gray matter. The present findings neither support a metabolic gender difference (except for a 1.3-fold higher myo-inosito l level in parietal white matter of female subjects) nor a metabolic h emispheric asymmetry.