Findings
A homogeneously enhancing, contrast filled venous pouch of size 5.1 cm x 3.47 cm x 4 cm (AP x TR x CC) is noted in the right parietotemporal lobe. Multiple prominent draining veins are noted emanating from the venous pouch and draining into the posterior part of the superior sagittal sinus. A prominent arterial twig from the adjacent right middle cerebral artery branch is noted on dynamic post-contrast MR angiography sequence, which is supplying the venous pouch. Mild mass effect in the form of effacement of the atria of the right lateral ventricle is noted by the venous pouch.
Diagnosis
Pial arteriovenous fistula
Summary
- Pial AVFs are vascular malformations that usually consist of a single dilated pial artery connecting directly to an enlarged cortical draining vein.
- 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 .
- These are rare entities accounting for 1.6% of all intracranial vascular malformations.
- 80% of pAVFs are supratentorial and typically lie adjacent to the ventricular ependyma or just beneath the brain surface.
- Cerebral DSA gold standard for diagnosis.
- Treatment options: endovascular embolization or microsurgical resection.
- Stereotactic radiogsurgery is considered in cases difficult to reach or lesion is too small. However success is less than in AVM
Further reads
- Pial arteriovenous fistula: A clinical and neuro-interventional experience of outcomes in a rare entity. Indian J Radiol Imaging. 2020 Jul-Sep; 30(3): 286–293.doi: 10.4103/ijri.IJRI_
- Pediatric Intracranial Nongalenic Pial Arteriovenous Fistulas: Clinical Features, Angioarchitecture, and Outcomes. AJNR Am J Neuroradiol. 2012 Oct; 33(9): 1710–1719. doi: 10.3174/ajnr.A3194
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