perivascular

Perivascular is an anatomical term describing tissue, processes, or structures that surround a blood vessel or lymphatic vessel. The term is used across anatomy, pathology, and radiology to distinguish elements located at or around vessels from those in other compartments. Perivascular tissue includes the adventitia and surrounding connective tissue, fat, and resident immune cells.

In the brain and spinal cord, the perivascular space (often called the Virchow–Robin space) surrounds penetrating arteries and veins as they pass from the subarachnoid space into the parenchyma. These spaces are part of the glymphatic system and participate in interstitial fluid drainage. Enlargement of perivascular spaces can occur with aging or small vessel disease and may be seen on MRI as lacunar-like cavities.

Pathologically, perivascular cuffing refers to accumulation of inflammatory cells around vessels and is a common feature in infections and CNS inflammatory diseases. Perivascular demyelination is a hallmark of multiple sclerosis, with inflammatory cells surrounding small veins. Perivascular inflammation can also accompany vasculitides and other connective tissue diseases.

Perivascular adipose tissue surrounds larger vessels and can influence vascular function through paracrine signaling and inflammatory processes, particularly in obesity and metabolic syndrome. In diagnostics, the term perivascular is used to describe imaging and histological findings related to the vessels’ surrounding tissue.