Regional Metabolic Assessment of Human Brain during Development by Proton Magnetic Resonance Spectroscopy In Vivo and by High-Performance Liquid Chromatography/Gas Chromatography in Autopsy Tissue

To study the course of regional metabolite concentrations during early brain development, we measured in vivo metabolites [N-acetyl-aspartate (NAA), choline-containing compounds, and myo-inositol (M-Ino)] in the precentral area of the cerebrum by short echo-time single volume proton magnetic resonance spectroscopy and compared in vivo established spectroscopic data with classic chromatographic data (HPLC) on age-corresponding autopsy tissue in different regions of the brain. In autopsy tissue, regional (frontal lobe, precentral area, basal ganglia, thalamus) and age-dependent differences of the concentration of creatine, NAA, and M-Ino were determined. In vivo measurement of NAA by proton magnetic resonance spectroscopy shows a significant increase of NAA by increasing postconceptional age. M-Ino shows a weak correlation and a nonsignificant decrease with increasing postconceptional age. Choline shows no age-dependent changes. Creatine concentrations measured by HPLC in different regions of the developing brain at autopsy showed an age-dependent increase that was identical for the left and right side and similar for the precentral area and frontal lobe and more pronounced for the basal ganglia and thalamus. Comparison of the results obtained by the two methods shows agreement for the age-dependent changes and the absolute concentration of M-Ino. NAA determined in autopsy tissue by HPLC is significantly lower than that measured in vivo by proton magnetic resonance spectroscopy. A comparison of the concentrations measured by HPLC in frontal lobe, basal ganglia, and thalamus with the results obtained from the precentral area showed significant regional differences in all measured metabolites. These results define important age-dependent changes detected with both methods and further indicate limitations of both methods that have to be considered when presenting absolute concentration values.