ON THE IDENTIFICATION OF CEREBRAL METABOLITES IN LOCALIZED H-1-NMR SPECTRA OF HUMAN BRAIN INVIVO

Localized H-1 NMR spectra of human brain in vivo are affected by signal overlap, strong spin-spin coupling, and complex J modulation, and therefore differ considerably from those obtained at higher magnetic fields. This paper deals with the assignment of H-1 NMR resonances of cerebral metabolites under the experimental conditions used for human investigations. Conventional 7.0-T FID spectra and 2.0 T localized, short echo time STEAM spectra (TE = 20 ms) of aqueous metabolite solutions are compared to in vivo brain spectra of human volunteers and patients. In addition to singlet resonances from N-acetyl aspartate (NAA), creatines, and cholines, short echo time STEAM spectra exhibit multiplets due to the NAA aspartyl group, glutamate, taurine, and myo-inositol. Enhanced levels of cerebral glutamine are detected in patients with liver cirrhosis. For the first time elevated levels of brain glucose are observed in patients with diabetes mellitus.