title: Annual rupture risk of growing unruptured cerebral aneurysms detected by magnetic resonance angiography.
abstract: OBJECTIVE
  In this paper, the authors' goals were to clarify the characteristics of growing unruptured cerebral aneurysms detected by serial MR angiography and to establish the recommended follow-up interval.
  
  
  METHODS
  A total of 1002 patients with 1325 unruptured cerebral aneurysms were retrospectively identified. These patients had undergone follow-up evaluation at least twice. Aneurysm growth was defined as an increase in maximum aneurysm diameter by 1.5 times or the appearance of a bleb.
  
  
  RESULTS
  Aneurysm growth was observed in 18 patients during the period of this study (1.8%/person-year). The annual rupture risk after growth was 18.5%/person-year. The proportion of females among patients with growing aneurysms was significantly larger than those without growing aneurysms (p=0.0281). The aneurysm wall was reddish, thin, and fragile on intraoperative findings. Frequent follow-up examination is recommended to detect aneurysm growth before rupture.
  
  
  CONCLUSIONS
  Despite the relatively short period, the annual rupture risk of growing unruptured cerebral aneurysms detected by MR angiography was not as low as previously reported. Surgical or endovascular treatment can be considered if aneurysm growth is detected during the follow-up period.
authors.affiliation: Department of Neurosurgery, Kohnan Hospital, and Tohoku University Graduate School of Medicine, Miyagi, Japan. tainoue@kohnan-sendai.or.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Inoue
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Shimizu
authors.forename: Miki
authors.initials: M
authors.lastname: Fujimura
authors.forename: Atsushi
authors.initials: A
authors.lastname: Saito
authors.forename: Teiji
authors.initials: T
authors.lastname: Tominaga
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017542:Aneurysm, Ruptured / Q000453:epidemiology* / Q000473:pathology / Q000601:surgery; D002343:Carotid Artery, Internal / Q000473:pathology / Q000601:surgery; D002533:Cerebral Angiography; D018450:Disease Progression; D057510:Endovascular Procedures; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications* / Q000453:epidemiology* / Q000473:pathology; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000473:pathology / Q000601:surgery; D019635:Neurosurgical Procedures; D012189:Retrospective Studies; D012306:Risk