Over the past 11 years, a total of 322 patients with UCAs (unruptured cerebral aneurysms) were seen in our hospital, and 165 patients were observed. Among these 165, 69 were followed up annually with MRA or 3D-CTA. The status of the remaining 96 patients could not be radiologically followed up. In patients who were radiologically followed up, the aneurysms ruptured in 2 (rupture rate was 1.0% per year) and enlargement was noted in 8 (4.1% incidence per year). In unobserved patients, rupture occurred in 7 (2.9% per year). Aneurysm size was the sole factor related to rupture, whereas younger age and multiplicity of UCAs were significantly related to the growth of aneurysms. Aneurysms in female patients tended to increase in size over time.
The results indicated that follow-up with 3D-CTA or MRA at certain intervals has the potential to detect enlargement of UCAs before rupture.