Physicians and scientists have seen fluid-filled spaces around blood vessels in the brain for decades and while we have known that they were associated with hypertension and cerebral amyloid angiopathy, most people interpreted these spaces as a benign finding of little clinical importance. Our collaborator, Angela Jefferson, recently published a landmark paper in the journal Neurology where she and her team at the Vanderbilt Memory and Aging Project discovered that perivascular spaces detected on MRI are associated worse cognitive performance. This effect was separate from the cognitive effects seen with white matter disease and cerebral microhemorrhages which have received comparatively more attention.
The study was profiled by Nature Reviews Neurology who concluded “[Perivascular spaces] showed associations with executive function and information processing speed performances beyond the other markers, suggesting that they might contribute to adverse cognitive health through a unique pathway.”
Dr. Julie A. Schneider from Rush University Alzheimer’s Disease Center and Dr. Anand Viswanathan from the Massachusetts General Hospital Stroke Research Center commented in an editorial that accompanied the manuscript: “This study adds two important findings to the literature. First, it adds to a growing literature that EPVS are important markers of cognitive performance. Indeed, [enlarged perivascular spaces] had a dramatic effect, equivalent to 15 years of age in information processing. The second take-home message, and perhaps of greater importance, is that different types of vascular tissue injuries in aging have independent associations with cognitive performance. Therefore, looking at only one type of abnormality is likely to provide an incomplete picture of the magnitude of the vascular contributions.”
We do not know why these spaces form. One theory is that the spaces are enlarged because the brain cannot effectively clear waste products in the interstitial fluid. Another hypothesis is that perivascular spaces form as neurons die and the brain atrophies. Either way, the current study focuses new attention on this previously neglected MRI finding.
This study was featured in the March 22, 2019 issue of the VUMC Reporter.