PT - JOURNAL ARTICLE AU - Bown, Corey W. AU - Carare, Roxana O. AU - Schrag, Matthew S. AU - Jefferson, Angela L. TI - Physiology and Clinical Relevance of Enlarged Perivascular Spaces in the Aging Brain AID - 10.1212/WNL.0000000000013077 DP - 2022 Jan 18 TA - Neurology PG - 107--117 VI - 98 IP - 3 4099 - http://n.neurology.org/content/98/3/107.short 4100 - http://n.neurology.org/content/98/3/107.full SO - Neurology2022 Jan 18; 98 AB - Perivascular spaces (PVS) are fluid-filled compartments that are part of the cerebral blood vessel wall and represent the conduit for fluid transport in and out of the brain. PVS are considered pathologic when sufficiently enlarged to be visible on MRI. Recent studies have demonstrated that enlarged PVS (ePVS) may have clinical consequences related to cognition. Emerging literature points to arterial stiffening and abnormal protein aggregation in vessel walls as 2 possible mechanisms that drive ePVS formation. We describe the clinical consequences, anatomy, fluid dynamics, physiology, risk factors, and in vivo quantification methods of ePVS. Given competing views of PVS physiology, we detail the 2 most prominent theoretical views and review ePVS associations with other common small vessel disease markers. Because ePVS are a marker of small vessel disease and ePVS burden is higher in Alzheimer disease, a comprehensive understanding about ePVS is essential in developing prevention and treatment strategies.AD=Alzheimer disease; CAA=cerebral amyloid angiopathy; ePVS=enlarged perivascular spaces; IPAD=intramural periarterial drainage; ISF=interstitial fluid; PVS=perivascular spaces; SMC=smooth muscle cell; STRIVE=Standards for Reporting Vascular Changes on Neuroimaging; WMH=white matter hyperintensity