経時的3DDSA fusion画像で仮性動脈瘤の位置を同定しtarget embolizationを行い得た破裂AVMの1例

A Case of Ruptured Arteriovenous Malformation Successfully Treated with Target Embolization for Pseudoaneurysm Detected Using Chronological Three-dimensional Digital Subtraction Angiography Fusion Images

Ⅰ．はじめに

　脳動静脈奇形（arteriovenous malformation：AVM）は約半数が出血で発症し，出血源としては動脈瘤が関連することが多い^1,9,13)．また，出血例では1年以内の再出血率が6〜15%と非常に高く，再出血を予防することが肝要である^2,3,17)．しかし，広範なnidusを伴うAVMの場合，開頭術や血管内治療，放射線治療を駆使しても根治することはしばしば困難である．そのため，出血点となる動脈瘤を正確に同定してtarget embolizationを行うことで，出血リスクを低減することができる^6,11)．

　近年，2つの異なる血管のthree-dimensional digital subtraction angiography（3DDSA）画像を組み合わせた3DDSA fusion画像は，脳血管病変，特にAVMや硬膜動静脈瘻（dural arteriovenous fistula：dAVF）において血管構築を理解し，治療計画を決定する上で有用なツールとなっている．今回，塞栓術1カ月前と術直前の3DDSAをfusionさせた経時的3DDSA fusion画像（chronological 3DDSA fusion images）により，新規に同定された仮性動脈瘤を塞栓し得た破裂AVMの1例を報告する．

　We herein report a case of ruptured arterio-venous malformation（AVM）detected using three-dimensional digital subtraction angiography（3DDSA）fusion images and successfully treated with target embolization for pseudoaneurysm. A 50-year-old man with a history of AVM was admitted to our department for the treatment of ruptured high-grade AVM in the right parietal lobe. Although a bleeding point was not evident on DSA, the patient had re-rupture in the right ventricle, one month after admission. Chronological 3DDSA fusion images generated from 3DDSA images taken on admission and after re-rupture revealed a newly visualized intranidal pseudoaneurysm near a hematoma. Contrast-enhanced magnetic resonance imaging showed vessel wall enhancement along the posterior horn of the right ventricle;this enhancement corresponded to the location of the pseudoaneurysm. We planned target embolization for the intranidal pseudoaneurysm to prevent re-bleeding. The origin of the feeder was so steep that a microcatheter could not be advanced deeply, and embolization with 20% n-butyl-2-cyanoacrylate resulted in proximal occlusion. Follow-up angiography 1 week after embolization showed complete disappearance of the pseudoaneurysm, and the patient had no recurrence of aneurysm until one year.