Imaging description

Virchow–Robin spaces (VRS) (a.k.a. perivascular spaces) are fluid spaces around arteries and veins that extend from the subarachnoid space through the brain parenchyma. VRS contain interstitial fluid, which cannot be differentiated from CSF on imaging studies [1]. VRS are routinely seen on MRI, particularly high-quality MRI, in all age groups and are considered to be a normal finding [2]. The most common locations of VRS include the basal ganglia, specifically the inferior portions of the putamen and globus pallidus, periventricular and subcortical regions of the supratentorial brain, and the brainstem, in particular the midbrain and pons.

VRS show identical signal to CSF on all pulse sequences and lack surrounding signal abnormalities and enhancement (Fig. 52.1). Particularly in the elderly, VRS can have a confluent appearance (Fig. 52.2). Rarely, dilated VRS can attain large sizes and bizarre shapes and mimic cystic mass lesions (Fig. 52.3) [3]. They may rarely be symptomatic from mass effect. The number and size of the VRS increase with age, but it is common to see VRS in young children. An association between dilated VRS and cerebral microvascular disease and Alzheimer disease has been reported, but no causal relationship has been established with these or other diseases [4,5].