High-grade Cerebral Arteriovenous Malformation Treated with Targeted Embolization of a Ruptured Site: Wall Enhancement of an Intranidal Aneurysm as a Sign of Ruptured Site

Partial targeted embolization of the ruptured site of cerebral arteriovenous malformations (AVMs) is considered effective to prevent rebleeding. The site of rupture is usually determined by morphological features, such as an intranidal aneurysm or a venous varix; however, the site can be difficult to identify in high-grade AVM with complicated angioarchitecture. The authors present a case of a 36-year-old woman with high-grade AVM presented with repeated hemorrhage. Cerebral angiography showed intranidal aneurysm, which was considered the ruptured site. The T(1)-weighted imaging with gadolinium enhancement demonstrated linear enhancement along the outer surface of the thickened wall of the intranidal aneurysm, which could be supplementary information to identify the ruptured site. Obliteration of the intranidal aneurysm was successfully achieved by emergent targeted embolization using N-butyl cyanoacrylate. The patient recovered and regained an independent status. The patient underwent volume-staged radiosurgery and experienced no further hemorrhage during the 26 months follow-up. Targeted embolization of the ruptured site is considered effective to prevent rebleeding in high-grade cerebral AVMs. Wall enhancement of the intranidal aneurysm, in addition to the structural characteristics, could be helpful in identifying the site of rupture embedded in the complicated angioarchitecture.