Cerebral perfusion and amyloidosis in the oldest-old.

Introduction: In a nested case-control study, we examined how cerebral perfusion relates to cognitive status and amyloid in the oldest-old (i.e., 90 years of age and older).
Methods: Study participants included 113 dementia-free older adults (76 cognitively normal [CN]; 37 cognitively impaired, no dementia [CIND]) from the 90+ Study (mean age = 92.9, SD = 2.4). We quantified regional perfusion from arterial spin labeling-MRI (magnetic resonance imaging) and amyloid deposition from florbetapir-positron emission tomography (PET) in a region comprising the posterior cingulate and precuneus (PCC+PCu), and additionally quantified perfusion in other regions important for cognitive decline (medial temporal lobe, inferior parietal lobe, and orbitofrontal cortex).
Results: Participants with CIND displayed lower perfusion in the PCC+PCu relative to participants who were CN, but there was no statistically significant difference between the groups in amyloid burden in this region. In addition, participants with CIND exhibited lower inferior parietal and higher orbitofrontal perfusion.
Discussion: Cerebral perfusion is related to cognitive status in the oldest-old independent of amyloidosis.
Highlights: Cerebral perfusion and amyloid positron emission tomography (PET) were measured in older adults: 90 years of age and older. Perfusion but not amyloid differed between cognitively impaired and normal groups. Frontal and parietal regions linked to cognitive decline had altered perfusion. Perfusion is related to cognitive status in the oldest-old independent of amyloid.
(© 2024 The Author(s). Alzheimer's & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer's Association.)