Mapping pathological 99mTc-HMPAO uptake in Alzheimer's Disease and Frontal Lobe Dementia with SPECT.

Seventeen patients with probable Alzheimer Disease (AD), seven patients with Frontal Lobe Dementia (FLD) and nineteen control subjects (NOR) were examined by 99mTc-HMPAO SPECT. Images were standardised in the same 3D space and averaged within each group. After normalisation the three sets of images were analysed in all cerebral lobes, hippocampus, thalamus and basal ganglia. In AD the 99mTc-HMPAO uptake values were significantly reduced, as compared to NOR, in parietal, temporal and insular lobes. In patients with FLD the uptake was reduced in all lobes with the exception of the parietal lobe. The uptake in nucleus caudatus decreased significantly in both AD and FLD as compared to NOR. The uptake in anterior cingulate cortex was significantly reduced in FLD. Subtraction images highlighted all significantly decreased areas. In conclusion, standardising SPECT in a common space and subtracting data from a control group improves the visual interpretation of images. In this study the typical temporo-parietal and fronto-parietal 99mTc-HMPAO uptake reductions were found in AD and FLD respectively. The uptake in nc. caudatus was found to decrease significantly in AD and FLD and the one in anterior cingulate cortex was reduced in FLD.