TC-99M-HMPAO-SPECT IN THE DIAGNOSIS OF SENILE DEMENTIA OF ALZHEIMERS TYPE - A STUDY UNDER CLINICAL ROUTINE CONDITIONS

This study was designed to evaluate, whether investigations of cerebra l blood flow can be a helpful diagnostic tool in the differential diag nosis between (senile) dementia of Alzheimer's type [(S)DAT] and geria tric depression with cognitive impairment. Under clinical routine cond itions we performed Single Photon Emission Computed Tomography (SPECT) using Tc-99m-Hexamethylpropyleneamine Grime (HMPAO) in 23 patients wi th (S)DAT (14f, 9m; mean age 68.9y), 17 patients with geriatric depres sion (9f, 8m; mean age 66.4y) and 12 age-matched controls (9f, 3m; mea n age 69.2y). Semiquantitative analysis (corticocerebellar ratios) of eight different regions of interest (ROI) revealed a significantly (p < 0.05) reduced perfusion in the (S)DAT patients compared to the contr ol group. The depression group exhibited perfusion values between the (S)DAT and control group. The difference between the depression and (S )DAT group was most prominent in the left parieto-occipital ROI(p = 0. 008). We discuss the data with extensive regard to the literature and conclude that Tc-99m-HMPAO SPECT is a valuable additional tool in the differential diagnosis of depression and dementia in the elderly.