Pial arteriovenous fistulae (pAVF) are rare vascular malformations that usually consist of a single dilated pial artery connecting directly to an enlarged cortical draining vein.
Terminology
pAVFs are distinct from pial arteriovenous malformations because they do not have a nidus and distinct from dural arteriovenous fistula (dAVF) because they arise from a pial artery rather than a dural artery 1.
Epidemiology
These are rare entities accounting for 1.6% of all intracranial vascular malformations 2.
Radiographic features
Unlike dAVFs, 80% of pAVFs are supratentorial and typically lie adjacent to the ventricular ependyma or just beneath the brain surface.