Embolization of arteriovenous fistula after radiosurgery for multiple cerebral arteriovenous malformations

Cerebral arteriovenous malformation (CAVM) associated with arteriovenous fistula (AVF) is rare. It may be difficult to identify hemodynamic details of mixed CAVM and AVF, even when using x-ray cerebral angiography (digital subtraction angiography). We report on a 37-year-old male patient with headache that led to an initial diagnosis of deep frontotemporal CAVM. The first DSA revealed engorged, tortuous, and high-flow venous drainage in addition to clusters of vasculature niduses. The patient was initially treated using gamma-knife radiosurgery (GKRS), which resulted in partial nidus obliteration, documented by a series of follow-up magnetic resonance imaging (MRI). However, the high-flow venous drainage remained, seen on MRI as engorged venous pouches. Clinically, the patient was bothered by persistent headache and bruits after GKRS. Follow-up DSA 3 years after GKRS confirmed a small remnant CAVM nidus and a nearby AVF, separated from and lateral to the original CAVM nidus in the ipsilateral deep temporal lobe. When the initial DSA was reviewed, it revealed that the AVF was difficult to define because of superimposition of the nidus and engorged drainage vessels. Embolization of the AVF using electrodetachable coils resulted in total occlusion of the AVF. The patient's symptoms resolved immediately after embolization. This case suggests that superselective angiography using a microcatheter may be necessary for the initial diagnosis of CAVM associated with AVF with high-flow and engorged venous drainage. For CAVM patients with persistent symptoms after radiosurgery and engorged venous drainage when CAVM is expected to be cured, a microcatheter and superselective endovascular approach may offer diagnosis. Immediate embolization for associated AVF in the same angiographic session may thereby improve neurologic deficits and reduce hemorrhagic risk during the latency after GKRS.