Regression of dilated perivascular spaces of the brain.

PURPOSE: Perivascular, or Virchow-Robin, spaces of the brain represent interstitial fluid-filled spaces continuous with subpial spaces, and not invagination of cerebrospinal fluid-filled subarachnoid spaces. Regression of a dilated, or even giant, perivascular space occurs rarely. The purpose of this paper is to describe magnetic resonance imaging evidence of complete regression of dilated perivascular spaces (dPVSs). METHODS: Patient 1 was a 76-year-old woman with right hemiparesis and aphasia from a left cranial vault meningioma infiltrating the superior sagittal sinus, and a left temporal lobe giant perivascular space. Patient 2 was a 70-year-old man with pituitary apoplexy, vasospasm, cerebral ischemia, and two dPVSs, one in the right temporal lobe, and one in the left anterior perforate substance. Patient 3 was a 78-year-old man with a generalized seizure, and a right temporal lobe dPVS. RESULTS: In all the patients, temporal lobe giant or dPVSs underwent regression, following meningioma subtotal resection (patient 1) or pituitary lesion shrinkage (patient 2), or spontaneously (patient 3). In patient 2, the left anterior perforate substance dPVS was unchanged. CONCLUSIONS: Temporal lobe giant or dPVSs may regress, eventually together with resection or regression of intracranial tumors, also distant from the PVSs. Cerebral edema does not seem the only factor influencing dilatation of PVSs.