SPECT brain imaging in Alzheimer's disease during treatment with oral tetrahydroaminoacridine and lecithin

Abstract

Quantitative SPECT brain imaging was performed in five normal subjects and in six ambulatory patients with Alzheimer's disease before the initiation of treatment with tetrahydroaminoacridine (THA) and lecithin. Imaging data were acquired with a single-head SPECT camera and a high-resolution collimator after the intravenous injection of 5 mCi of (p,5n) I-123 IMP. Uptake per pixel in 28 regions of interest in the transverse projection of each study was normalized to uptake per pixel in the cerebellum. Perfusion in the patients with Alzheimer's disease was decreased compared with that of the subjects. Perfusion was decreased greater than 2 SD below the mean in the posterior parietal cortex of 5/6 patients, in the temporal cortex of 3/6 patients, and in the frontal cortex of 2/6 patients with Alzheimer's disease. SPECT imaging was repeated in the six patients after initial titration to peak therapy with oral THA (75 to 200mg per day). The same abnormalities were again seen in the same patients. No dramatic clinical or behavioral change in cerebral perfusion was observed from initial treatment of Alzheimer's disease with THA and lecithin.