VARIABILITY OF CEREBRAL BLOOD-FLOW DEFICITS IN TC-99M-HMPAO SPECT IN PATIENTS WITH ALZHEIMERS-DISEASE

The purpose of this study was to analyse the frequency of the differen t pathological perfusion patterns in SPECT in a clinical, unselected p opulation of patients with Alzheimer's disease. In 91 patients and 16 control subjects regional cerebral blood flow (rCBF) was measured with Single Photon Emission Computed Tomography (SPECT) using Tc-99m-hexa- methyl-propyleneamine oxime (HMPAO). 95% confidence intervals obtained from the perfusion values of the control subjects were used to define normal perfusion ranges. The frequency of perfusion deficits in the l eft frontal, temporal, parietal and occipital lobes were 62.2%, 60.4%, 70.3% and 23.1%, respectively. In the right hemisphere the correspond ing values were 60.4%, 58.2%, 63.7% and 9.9%. With the exception of th e occipital lobes these frequencies were not significantly different. The analysis of the perfusion pattern of each patient revealed 35 diff erent combinations of lobes with perfusion deficits. The temporo-parie tal perfusion deficits were not more frequent than the temporofrontal perfusion deficits. These results suggest that in the clinical routine a high variety of heterogeneous rCBF patterns have to be expected.