Cerebral perfusion and the risk for cognitive decline and dementia in community dwelling older people

Background. The arterial spin labeling-spatial coefficient of variation (sCoV) is a new vascular magnetic resonance imaging (MRI) parameter that could be a more sensitive marker for dementia-associated cerebral microvascular disease than the commonly used MRI markers cerebral blood flow (CBF) and white matter hyperintensity volume (WMHV).
Methods. 195 community-dwelling older people with hypertension underwent MRI twice with a three-year interval. Cognition was evaluated every two years for 6-8 years using the mini-mental state examination (MMSE). Dementia diagnoses were registered up to 9 years after the first scan. We assessed relations of sCoV, CBF and WMHV with cognitive decline during follow-up, and compared MRI parameters between participants that did and did not develop dementia.
Results. sCoV and CBF were not associated with MMSE changes during 6-8 years of follow-up and did not differ between participants who did (n=15) and did not (n=180) develop dementia. Higher WMHV was associated with declining MMSE scores (-0.15 points/year/ml, 95%CI=-0.30; -0.01), and with participants who developed dementia after the first MRI (13.3 vs 6.1mL, p<0.001). There were no associations between longitudinal change in any of the MRI parameters and cognitive decline or subsequent dementia.
Conclusion. Global sCoV and CBF were less sensitive longitudinal markers of cognitive decline and dementia compared to WMHV in community-dwelling older people with hypertension. Larger longitudinal MRI perfusion studies are needed to identify possible (regional) patterns of cerebral perfusion preceding cognitive decline and dementia diagnosis.