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P2‐251: Volumetric but not resting blood flow changes are associated with increased PIB uptake in cognitively normal individuals: Results of the Adult Children Study
Author(s) -
Blazey Tyler,
Ances Beau,
Mityul Marina,
Roe Catherine,
Sheline Yvette,
Su Yi,
Snyder Abraham,
Morris John,
Benzinger Tammie
Publication year - 2012
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2012.05.959
Subject(s) - atrophy , cerebral blood flow , psychology , cardiology , medicine , neuroscience
Background: Cortical atrophy, amyloid deposition, and disrupted resting cerebral blood flow (rCBF) are all hallmarks of Alzheimer’s disease (AD). Recent work (Chen et. al, 2011) has shown that age-related changes in cerebral blood flow and atrophy are independent measures. Here we expand upon this finding by further exploring the relationship between atrophy, amyloid accumulation, and rCBF in cognitively normal (CDR 0) older individuals. Methods: 73 participants (21M, 52F; mean age 1⁄4 62.3 (from 50 to 79 y.o.) from the Adult Children Study (ACS) at Washington University had MRI and [11C]PIB-PET scans. rCBF was measured using a pulsed arterial spin labeling (pASL) sequence. Each participant’s cortical thickness, PIB, and CBFmaps were transformed to a common surface-based atlas using FreeSurfer. Multivariate linear regression was used on a vertexby-vertex basis to examine the relationships between age, atrophy, PIB binding, and rCBF. In order to examine age-related rCBF and thickness changes that were independent from changes in amyloid deposition, separate regression analyses were conducted using PIB as a vertex-wise covariate.Results: As expected, age was associated with significant increases in PIB and decreases in cortical thickness (Figure 1) throughout the brain, especially in regions within the default mode network. In contrast, age was associated with a significant decrease in rCBF in the occipital and parietal lobes. A significant interaction with PIBwas found for thickness, but not rCBF.Conclusions: In our cognitively normal sample, age-related decreases in rCBF of the occipital and parietal lobes are independent of amyloid deposition (by PIB). In contrast, additional cortical thickness decreases were associated with PIB deposition beyond the age-related changes. This suggests that the atrophy associated with PIB may occur independent of blood flow decreases in AD. Longitudinal studies in these participants are ongoing and will be required to further examine this temporal relationship as a portion of this population transitions to dementia. References: Chen et al. Neuroimage (2011).