経過観察中に増大した無症候性未破裂脳動脈瘤の3例

Growth of Asymptomatic Unruptured Aneurysms in Follow-up Study: Report of Three Cases

Ⅰ．はじめに

　脳動脈瘤が発生後，どのような経過をたどるのか，例えば未破裂脳動脈瘤が増大，破裂に到る経過については未だ十分に明らかにされていない．今回，経過観察中の画像診断〔MRA, MRI, 3D—CT angiography（3D-CTA）〕にて無症候性未破裂脳動脈瘤3例外増大し，そのうち2例が破裂し，くも膜下出血（以下SAH）を来した．そこでわれわれは，経過観察中の画像診断における未破裂脳動脈瘤の変化，および画像上の破裂危険因子について検討した．

The natural history of asymptomatic unruptured aneurysms that have not been subjected to surgery was studied radiologically using MRA and MRI and 3D-CT angiography (3D-CTA) commencing in 1993. We report on the growth of documented asymptomatic unruptured aneurysms in three patients. Growth of the aneurysms was followed by re-peated MRA, MRI and 3D-CTA.

In Case 1, a 71-year-old woman had been diagnosed as having a 3mm unruptured anterior cominunicating artery aneurysm. The size of the aneurysm had expanded to 4mm, 2 years later. This was detected during a follow-up MRA and confirmed by angiography.