Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

Reductions in regional cerebral perfusion, particularly in the posterior temporo-parietal lobes, are well recognized in Alzheimer's disease. We set out to correlate perfusion changes, using (99m)Tc-HMPAO single photon emission tomography (SPET), with the pathological stage of Alzheimer's disease. The 'Braak stage' of the distribution of neurofibrillary pathology in post-mortem brains was used to classify SPET scans taken in life from a mixed (dementia and control) elderly population into the entorhinal stage (n = 23 subjects), limbic stage (n = 30 subjects) and neocortical stage (n = 36 subjects) Alzheimer's disease pathology. The SPET scans were then registered to a common, standard Talaraich space, and single template scans produced for each pathological stage. Comparison of these templates revealed an evolution in the pattern of reduction in regional perfusion. Additional comparisons were performed using earlier SPET scans obtained 5 years before death. For comparisons between templates, a threshold of 10% perfusion change was chosen so as to be clinically relevant as well as statistically significant. Reduced perfusion appears between the entorhinal and limbic stages in the anterior medial temporal lobe, subcallosal area, posterior cingulate cortex, precuneus and possibly the supero-anterior aspects of the cerebellar hemispheres. Large posterior temporo-parietal perfusion defects then appear between the limbic and neocortical stages, before finally large frontal lobe perfusion defects. The time course of these perfusion defects appears relatively long, suggesting that perfusion changes may have scope to be a diagnostic aid in staging Alzheimer's disease in life. The reduction in anterior medial temporal lobe perfusion may have future relevance on modern high resolution SPET and PET systems and also perfusion-type MRI sequences.


Journal article



Publication Date





1772 - 1781


Aged, Aged, 80 and over, Alzheimer Disease, Brain, Female, Humans, Male, Organ Specificity, Radiopharmaceuticals, Technetium Tc 99m Exametazime, Tomography, Emission-Computed, Single-Photon