T1, T2, and concentrations of brain metabolites in neonates and adolescents estimated with H-1 MR spectroscopy.

The protein and lipid content of the human brain increases dramatically from infancy to adolescence. The authors investigated whether this change influences the relaxation behavior of metabolites measurable with hydrogen-1 magnetic resonance (MR) spectroscopy. H-1 MR spectroscopy was performed in eight neonates and eight adolescents at 1.5 T with STEAM (stimulated-echo acquisition mode) sequences. Five spectra were obtained in each volume of interest with different TE and TR values. T1 and T2 were subsequently calculated. T1 and T2 for inositols, choline-containing compounds (Cho), phosphocreatine plus creatine (PCr + Cr), and N-acetylaspartate (NAA) did not differ significantly between the two subject groups. Metabolite concentrations were estimated by using the fully relaxed water signal as an internal standard. Mean estimated concentrations of NAA and PCr + Cr were higher in the adolescent group, whereas the concentration of Cho was lower. The concentration of inositols was similar in the two groups.