Perivascular Spaces

Perivascular spaces (PVS) are visible on brain MRI as small, linear hyperintensities on T2-weighted imaging or hypointensities on T1-weighted imaging, with signal characteristics similar to the CSF.1 Persons with cerebral small vessel disease have a higher number of visible PVS. Indeed, the Standards for Reporting Vascular Changes on Neuroimaging2 radiologically classify and define PVS, along with 5 other lesion types, as typical manifestations of cerebral small vessel disease. But until recently, PVS have played the role of the neglected cousin to other canonical manifestations of cerebral small vessel disease—lacunes, microbleeds, and white matter hyperintensities (WMH). In clinical practice, they are rarely reported unless their number and size are extreme. This underreporting may need to change, however, as evidence emerges that they convey clinically relevant information on prognosis and diagnosis.