. Increased s-amyloid deposition is related to regional cerebral blood flow in nondemented older adults. Human Amyloid Imaging 2011 Meeting Abstracts. 2011 Jan 15;

Abstract:

Approximately 30% of nondemented older adults have elevated fibrillar s-amyloid (As) in the brain. Whether these individuals have changes in brain function that are associated with As has not been extensively studied. We hypothesize that As accumulation is related to regional cerebral blood flow (rCBF) even in nondemented elderly.

Methods: Fifty-five nondemented participants (78.5}6.3 years, 24 females, 6 CDR = 0.5) in the Baltimore Longitudinal Study of Aging underwent [15O]-water PET and dynamic [11C]PiB PET. A simplified reference tissue model with linear regression and spatial constraint (Zhou et al 2007) was applied to 15 regions of interest (ROI) drawn on co-registered MRIs to quantify distribution volume ratio (DVR) using cerebellum as reference region. Regressions of mean cortical DVR (mcDVR), representing an average of 8 cortical regions, and individual regional DVRs on [15O]-water PET scans were performed in SPM5, adjusting for age and sex.

Results: Increased mcDVR was associated with decreased grey matter rCBF in parahippocampal and inferior frontal regions and at the junction of the planum temporale and insula (p = 0.005, spatial extent k = 50). When search was restricted to CBF in cortical ROIs, regional DVRs negatively correlated with rCBF in the same region (p = 0.05, k = 50).

Conclusion: Elevated As is associated with alterations in brain function in nondemented older individuals. rCBF decreases in medial temporal and inferior frontal regions correlate with higher global As. Inverse associations between rCBF and regional As load are also seen. These findings suggest that increased As adversely affects brain function in nondemented older adults.

Support: This research was supported by the Intramural Research Program of the NIH, National Institute on Aging N01-AG-3-2124 and K24 DA000412 (DFW).

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  1. Miami: HAI Amyloid Imaging Conference Abstracts