Enlarged perivascular spaces

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Enlarged peri vascular spaces also called Virchow Robin (VR) spaces.
These are Pial lined interstitial fluid filled structures that accompany penetrating arteries, do not communicate with subarachnoid space.
Noted as an incidental finding and are of no clinical significance.

Typical and commonest location is basal ganglia, often bilateral.
Other common locations are sub insular cortex along external capsule, lobar white matter, thalami, mid brain.

Size is usually 5mm or less. Occasionally expand and attain large size up to several cms.

Usually found in clustures.
Iso intense to Csf on all pulse sequences.
Closest differential particularly on CT is a chronic lacunar infarct due to small vessel occlusion or a chronic lacune secondary to micro bleed ( in Peri vascular space surrounding brain parenchyma lacks Gliosis which is seen in case of chronic lacune or lacunar infarct as a thin rim of Gliosis on MRI FLAIR)

Enlarged Perivascular (Virchow Robin) Spaces

MRI Brain, Axial T2, FLAIR, Diffusion; CT Brain

Findings:
Multiple T2 hyperintense foci cluttered in right parietal white matter and a single in right frontal lobe white matter, complete signal suppression on FLAIR are the enlarged peri vascular spaces.
Hypodense on CT.
Adjacent brain show normal signals. No any evidence of Gliosis.

On CT, the closest differential is lacunar infarcts which can be ruled out by demonstrating absence of surrounding rim of Gliosis on MRI FLAIR.

Enlarged peri vascular spaces also called Virchow Robin spaces.
Typical and commonest location is basal ganglia.
Usually found in clustures.
Iso intense to Csf on all pulse sequences.
May be seen in lobar white matter and even in brain stem.