Abstract
Objectives : Unruptured Cerebral Aneurysm Study in Japan (UCAS Japan) has been conducted to clarify the natural course and management risk of unruptured cerebral aneurysm (UCA) in Japan. This paper presents the most recent results. Material : After informed consents were obtained, UCA found between Jan. 2001 and April 2004 in 404 institutions were prospectively registered on-line to the host computer. Periodical follow-up at 3, 12, and 36 months were requested. Results : As of June 2004, 6, 646 cases with 8, 161 aneurysms were registered. Clinical outcome and management results in the follow-up period of 8, 459 patient-year were assessed. Male-female ratio was one to two and median age was 63. The most frequent aneurysm was at the internal carotid artery followed by middle cerebral artery. The size of aneurysm ranged from 3 to 45mm (median 5mm). The most frequent reason for the diagnosis was vague symptoms such as headache or dizziness. 2, 423 patients underwent management during this period. Conclusion : Further data collection is being conducted. This study is believed to provide useful information to direct appropriate management of UCA.
