前大脳動脈水平部（A1部）紡錘形破裂脳動脈瘤の2症例

Two Cases of Ruptured Fusiform Aneurysm of the Proximal Anterior Cerebral Artery (A1 segment)

I．はじめに

　脳動脈瘤のうちアテローム硬化をもとに形成される紡錘状の動脈拡張は紡錘形脳動脈瘤と称され，脳底動脈，内頸動脈，中大脳動脈に稀ならず認められるが，前大脳動脈にこの種の動脈瘤をみることは少ない．われわれはすでに前大脳動脈水平部すなわちA₁部に発生した動脈瘤26例の検討を行い，そのうちで紡錘形のものが2例ありA₁部に発生するのは稀であると報告した^8）．今回この2症例の紡錘型動脈瘤に注目し，若干の文献的考察を加えたので報告する．

Two rare cases of fusiform aneurysms of A1 segment of the anterior cerebral artery are reported.

Case 1: A 62-year-old woman was admitted with sudden onset of severe headache and loss of conscious-ness, on August 22, 1982. CT scan showed subarach-noid hemorrhage at the basal cisterns. Left carotid angiography revealed a spindle shaped aneurysmal dilatation in the A₁ segment of the anterior cerebral artery. Four-vessel angiography was performed twice but no other aneurysm was found. She was treated con-servatively and the clinical course was not evenful.