SPECT in the diagnosis of Alzheimer's disease and multi-infarct-dementia.

SPECT with Tc-99m HM-PAO as a radiopharmaceutical was performed in 17 patients meeting research criteria for Alzheimer's disease (AD), in 10 patients with a clinical diagnosis of multi-infarct-dementia (MID) and in 12 healthy volunteers. Regional tracer uptake was measured in frontal, parietal, and temporoparietal regions. A statistically significant decrease of tracer uptake in the temporoparietal region was found in AD-patients compared with controls. AD-patients showed less activity in this region than MID-patients, but this difference did not reach statistical significance. In both AD- and MID-patients decrease of tracer uptake was not correlated with dementia severity. We conclude that SPECT brain imaging is not yet ready for routine use in the distinction between AD and MID.