perivascular spaces
Fluid-filled spaces surrounding blood vessels in the brain, appearing as punctate hyperintensities on T2-weighted images.
Full Definition
Perivascular spaces, also known as Virchow-Robin spaces, are cerebrospinal fluid-filled cavities that surround penetrating vessels as they traverse brain parenchyma. These spaces facilitate interstitial fluid drainage and are part of the brain's glymphatic system. On MRI, perivascular spaces appear as small, well-defined hyperintense foci on T2-weighted and FLAIR images, typically measuring 1-3mm in diameter. While normally present, enlarged or numerous perivascular spaces may indicate aging, hypertension, or impaired cerebrovascular function and must be distinguished from lacunar infarcts or white matter lesions.
Usage
Usage note: Distinguish from pathological lesions; grade severity when enlarged.
In Context
- "Enlarged perivascular spaces were prominent in the basal ganglia, consistent with chronic hypertensive changes." — Vascular risk assessment
- "The punctate T2 hyperintensities followed vascular distributions and were consistent with dilated perivascular spaces rather than infarcts." — Differential diagnosis report