Regional cerebral blood flow of Alzheimer's disease-like pattern in young patients with Down's syndrome detected by 99Tcm-HMPAO brain SPECT.

Fourteen young patients with Down's syndrome (nine males, five females, age range 8-30 years) were studied. 99Tcm-hexamethylpropylene amine oxime (HMPAO) brain single photon emission computed tomography (SPECT) was performed to evaluate regional cerebral blood flow (rCBF). Two experienced nuclear medicine physicians analysed the results of the SPECT by visual interpretation. The SPECT in all 14 patients with Down's syndrome invariably showed significantly unilateral perfusion defects in the temporal-parietal-occipital region, occasionally combined with small perfusion defects over other discrete cerebral areas. In this preliminary study, 99Tcm-HMPAO brain SPECT in the patients with Down's syndrome were abnormal. Patterns of rCBF in Down's syndrome were similar to the usual images of rCBF in Alzheimer's disease reported in the literature. Our findings provide new evidence of the similarities between Down's syndrome and Alzheimer's disease.