Onyx Embolization of Intracranial Pial Arteriovenous Fistula

Intracranial pial arteriovenous fistulas (AVFs) are rare cerebrovascular lesions consisting of one or more arterial connections to a single venous channel without an intervening nidus. Because of the location and high flow dynamics of these lesions, neurosurgeons may have a difficulty deciding between endovascular treatment and open surgical treatment. We report on a patient who underwent endovascular treatment with liquid embolic agent. A 50-year-old man with a decreased mental state and a tonic seizure event was brought to our hospital. Computed tomography (CT) of the brain showed a subcortical hematoma in the right temporoparietal lobe. On three-dimensional cerebral artery CT, there was no evidence of definite cerebrovascular abnormality. Cerebral angiography showed a pial AVF supplied by the right middle cerebral artery with early drainage into the right superior cerebral vein. The patient was treated with Onyx embolization for definitive closure of the fistula. The patient was transferred to the department of rehabilitation medicine two weeks later with grade 4 left hemiparesis. The application of advanced equipment, such as the latest angiography and endovascular tools, will facilitate the correct diagnosis and delicate treatment of pial AVF.