Pediatric Intracranial Nongalenic Pial Arteriovenous Fistulas: Clinical Features, Angioarchitecture, and Outcomes

Multi-hole AVF with delayed white matter calcifications and DAVF formation (patient 9). A 2-month-old boy presented with seizures, hypotonia, developmental delay, and nystagmus. A NECT at 2 months of age demonstrates a mass in the right temporal lobe (A) and no white matter calcifications. MRA (B) suggests an AVF involving the right PCA. DSA at 6 months of age (C) confirms 3 PCA branch shunting to a single markedly enlarged vein with associated marked venous sinus dilation (D, E). Initial transarterial coil embolization eliminated arteriovenous shunting, but a follow-up NECT at age 6 months demonstrates development of extensive white matter calcifications (F), and a T2-weighted MR imaging (G) at age 18 months demonstrates extensive white matter damage, both likely due to the patient's pre-embolization period of cerebral venous hypertension. A follow-up angiogram at age 3 years demonstrates de novo dural supply to the AVF from hypertrophied MMA and ascending pharyngeal artery (H), as well as recurrent mild shunting from small branches of the PCA (I, J). At that same time, DSA demonstrates resolution of venous sinus dilation (K). One year after ethanol embolization of the noneloquent distal anterior division MMA supply and surgical resection of the occipital fistula, no residual shunting was present but a pseudophlebitic pattern of medullary venous drainage was still evident (L). MMA indicates middle meningeal artery; NECT, nonenhanced CT; PCA, posterior cerebral artery.