In vivo proton magnetic resonance spectroscopy of the medial temporal lobes of subjects with combat-related posttraumatic stress disorder

Recent findings using volumetric MRI techniques have revealed that patients with combat-related and noncombat-related posttraumatic stress disorder (PTSD) have reductions in right hippocampal volume. Twenty-one veterans with PTSD and eight age-matched control veterans were studied using proton magnetic resonance spectroscopy to test the hypothesis that the N-acetyl-L-aspartic acid/creatine (NAP/Cr) ratio would be decreased in the right medial temporal lobe structures of patients with PTSD compared to controls. Patients with PTSD displayed significantly lower NAA/Cr ratio for the right medial temporal lobe relative Po the left (P less than or equal to 0.011). Patients with PTSD also had lower NAA/Cr in right medial temporal lobe (P less than or equal to 0.013) and lower choline/Cr in left medial temporal lobe (P less than or equal to 0.030) compared to control subjects. Because NAA is regarded as an indicator of neuronal density, this finding suggests that the neuronal density of right-sided medial temporal structures in patients with combat-related PTSD may be decreased.