[Single-photon emission-computed tomography in the differential diagnosis of dementia]

To assess the value of single photon emission computed tomography (SPECT) in the differential diagnosis of dementia SPECT and conventional computed tomography were performed in 77 patients (50 men, 27 women, mean age 59 [28-90] years) with dementia diagnosed by a battery of psychometric tests. In 13 out of 15 patients with dementia of Alzheimer type SPECT showed a typical Alzheimer pattern (bilateral parietotemporal perfusion defects). Both patients with dementia of Pick type had definite decreases in frontal perfusion. All 21 patients with dementia due to Huntington's chorea showed a typical pattern with absent perfusion of the head of the caudate nucleus, although in three of them conventional computed tomography didn't demonstrate complete atrophy of this structure. Out of 23 patients with multi-infarct dementia there were 17 with focal uptake deficits at various sites, while six displayed an Alzheimer pattern. In Korsakoff's syndrome (n = 11), Down's syndrome (n = 1), Fahr's syndrome (n = 2), senile chorea (n = 1) and HIV encephalopathy (n = 1) no typical distribution patterns were noted. Single photon emission computed tomography can make a contribution to the diagnosis and classification of primary degenerative dementias and can be used to differentiate them from other forms of dementia.