Reduced hippocampal N-acetylaspartate without volume loss in schizophrenia

Quantitative magnetic resonance imaging (MRI) can measure total gray matter volume but cannot discriminate between neurons and glia. Proton magnetic r esonance spectroscopic imaging (H-1 MRSI) measures N-acetylaspartate (NAA) which is a selective marker of neuronal loss or neuronal dysfunction. The o bjective of this study was to obtain quantitative measures of hippocampal v olume and hippocampal NAA to determine if there was evidence for hippocampa l neuronal dysfunction or neuronal loss in schizophrenia. Quantitative MRI and H-1 MRSI was performed on the right and left hippocampal regions in 23 chronic schizophrenic patients and 18 control subjects. Relative to the con trol group, the patients with schizophrenia demonstrated no change in hippo campal volumes bilaterally, but significantly decreased NAA in the hippocam pal regions bilaterally. There was also no correlation between hippocampal volumes and NAA in either the schizophrenics or controls. These findings su ggest that: (I) hippocampal NAA may be a more sensitive measure of neuronal loss than Volumetric measurements; and (2) reduced hippocampal NAA may be measuring neuronal dysfunction or damage rather than neuronal loss in this sample of schizophrenics. (C) 1999 Elsevier Science B.V. All rights reserve d.