PiB-PET Bests Genetic Factor for Showing Alzheimer’s Risk

Elevated beta amyloid in the brain, detected with PET imaging with PiB, may be better than genetic factors in predicting memory loss in healthy seniors.

Elevated beta amyloid load levels in the brain, detected with PET imaging with carbon-11-labeled Pittsburgh Compound B, may be better than genetic factors in predicting if healthy seniors will develop memory loss, according to a study in the journal Neurology.

Researchers from the University of Melbourne, Australia, undertook a prospective study to evaluate the significance of elevated cerebral beta amyloid (Aβ) load for longitudinal changes in cognition. One hundred forty one healthy and cognitively normal adults, mean age 76, underwent PET neuroimaging after Pittsburgh Compound B (PiB) injection for cerebral Aβ, APOE genotyping, and cognitive assessment as part of their baseline assessment (through card games and word memory games) in the Australian Imaging Biomarkers and Lifestyle study. The subjects’ cognitive function was reassessed 18 months later.

The researchers found at reassessment that subjects who demonstrated high cerebral Aβ in the PET imaging showed significantly greater decline in working memory and verbal and visual episodic memory than did those with low cerebral Aβ. No interaction was found between APOE ?4 and cerebral Aβ load for any measure of cognitive function.

Researchers also noted that the APOE ?4 genotype was associated with a decline in visual memory, although the effect was less than that observed for cerebral Aβ load.