Tc-99m HMPAO brain uptake patterns in patients with dementia of Alzheimer type

Conventional gamma camera SPECT with Tc-99m HMPAO (10 MBq/kg patient weight) was carried out in 21 patients with dementia of Alzheimer type (DAT), fulfilling the criteria established by the National Institute of Neurological and Communicative Disorders and Stroke and the ADRDA criteria (nine with amnesia as the main symptom [group 1], 12 with amnesia, aphasia, and/or apraxia and agnosia [group 2], and eight age-matched control subjects. Perfusion was quantitatively studied by means of cerebrum-cerebellum activity ratios. In group 1, perfusion deficits in the mesial cortex of the temporal lobes (right, 0.70; left, 0.68) were found, and ratios were significantly lower than in the control group (right, 0.77; left, 0.76 [P < .05]). Group 2 showed low ratios throughout both temporal lobes (mesial and lateral cortex), bilaterally in the posterior parietal cortex (right, 0.69; left, 0.66 [control: right, 0.80; left, 0.81] [P < .001]), and left frontal cortex (0.75 [control, 0.79] [P < .05]). In conclusion, SPECT with Tc-99m HMPAO identifies perfusion deficits in patients with DAT, and these correlate well with the clinical findings and are significantly different from those in the control group