Microvessel Stenosis and Density Analysis of Post Mortem WMH Detected Using Ultra High Field MRI in Aging, Cerebrovascular and Alzheimer Disease

Abstract

Cerebral small vessel disease (SVD) affects the microvasculature of the brain, increasing in prevalence with age and associating with cognitive decline and dementia. SVD can be visualized on MR imaging by markers such as hyperintensities within the white matter (WMH). Periventricular WMH within the frontal lobe specifically may have a negative effect on executive functions. Executive dysfunction represents a set of cognitive changes, including processing speed and attention, that can precede memory impairment in Alzheimer disease. The etiology and development of cerebral small vessel disease, including WMH, and it's relation to executive dysfunction is not well understood. Previous work has characterized the presence of stenosis of the arterioles, but little work has focused on the venules. In this study we sought to characterize alterations in microvascular stenosis and density including small and medium venules and arterioles within the frontal white matter. Post mortem 7‐Tesla MR imaging of formalin‐fixed coronal brain sections was performed on 20 brains with a neuropathological diagnosis of normal, cerebrovascular disease or Alzheimer disease. We calculated the percent stenosis within small, medium and large venules and arterioles within both the periventricular and subcortical white matter. Stenosis of the small (<50 um diameter) arterioles and venules within the periventricular white matter specifically was associated with increased severity of periventricular WMH. Small vein and artery stenosis was also associated with the presence of periventricular infarction identified on T1‐weighted imaging. This highlights the utility of multiple sequences when interpreting MRI findings within the white matter. Further study on markers of small vessel disease that affect executive functioning, such as frontal WMH, can help elucidate mechanisms that lead to cognitive decline prior to the onset of memory impairments and dementia.Support or Funding InformationCanada First Research Excellence Fund to BrainsCANCanadian Institutes of Health ResearchCanadian Consortium on Neurodegeneration in AgingThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.