Frontal hypoperfusion in depressed patients with dementia of Alzheimer type demonstrated on 3DSRT

Abstract

Depressive symptoms are common in patients with dementia of Alzheimer type (DAT) and contribute to clinical morbidity. Previous studies have suggested that hypoperfusion in the prefrontal cortex and anterior cingulate gyrus are involved in the pathophysiology of depression in DAT. Using 3-D stereotactic region of interest (ROI) template (3DSRT), fully automated ROI analysis software, the purpose of the present study was to investigate the relationship between depressive symptoms and regional cerebral blood flow (rCBF) in DAT. Technetium-99m-ethyl cysteinate dimer ((99m)Tc-ECD) single-photon emission computed tomography (SPECT) and Japanese version of the Neuropsychiatric Inventory (NPI) were carried out in 35 patients diagnosed as having mild-moderate DAT according to DSM-IV. These patients were divided into the depressive group (D group: n = 17) and non-depressive group (ND group: n = 18) using the NPI depression items. All data from SPECT images were analyzed using 3DSRT software. On 3DSRT the perfusion ratios (rCBF of bilateral callosomarginal, precentral, central, parietal, angular, temporal, posterior cerebral, pericallosal, lenticular nucleus, thalamus and hippocampus/cerebellar hemisphere) of each segment were compared between the D group and the ND group. The perfusion ratios of the left callosomarginal segment for the D group were significantly lower (P < 0.05) than those of the ND group. Hypoperfusion in the left frontal cortex contributes to the expression of depressive symptoms in patients with DAT.