Perivascular Spaces

perivascular spaces

Perivascular spaces, also known as Virchow-Robin spaces, are pial-lined interstitial fluid-filled spaces surrounding perforating vessels. They do not have a direct connection to the subarachnoid space, and indeed the fluid within them is slightly different. They typically are less than 5mm in diameter, but can reach much larger sizes, so-called giant perivascular space or tumefactive perivascular space, and can exert enough mass effect to be symptomatic.

Most commonly they are located in the lower half of the basal ganglia especially along the line of the anterior commisure. They are also found in the midbrain, deep white matter, extreme capsule… pretty much everywhere…

They are usually idiopathic, although they are seen in greater frequency in Hunter disease, Hurler disease and some muscular dystrophies.

They usually follow CSF on all modalities and sequences. Mostly there is no surrounding gliosis on FLAIR (c.f. lacunes which usually have more) although 25% will demonstrate a thin increased T2 halo. They generally have some positive mass effect, which again can be used to distinguish them from lacunes.

References: Osborn A, Blaser S, Salzman K. Diagnostic imaging: Brain. Amirsys 2004.

For additional images / sequences of this case please vist www.radiopaedia.org here.

Credit: Dr Frank Gaillard