title: Prevalence of asymptomatic incidental aneurysms: review of 4568 arteriograms.
abstract: OBJECTIVE
  The prevalence of unruptured cerebral aneurysms is unknown, but is estimated to be as high as 5%. The goal of this study was to determine the prevalence of asymptomatic incidental aneurysms.
  
  
  METHODS
  The authors studied all cerebral arteriography reports produced at a single institution, the University of Virginia, between April 1969 and January 1980. A review of 3684 arteriograms demonstrated 24 cases of asymptomatic aneurysms, yielding a prevalence rate of 0.65%. The majority (67%) of the 24 patients harboring unruptured aneurysms were women. More than 90% of the unruptured aneurysms were located in the anterior circulation and in locations similar to those found in patients with ruptured aneurysms. Nearly 80% of the aneurysms were smaller than 1 cm in their greatest diameter. The frequency of asymmetrical unruptured aneurysms (0.6-1.5%) was constant throughout all relevant age ranges (35-84 years).
  
  
  CONCLUSIONS
  While keeping in mind appropriate caveats in extrapolating from these data, the prevalence rate of asymptomatic unruptured aneurysms found in the present study allows an estimation of the yearly rate of rupture of these lesions. The authors suggest that this yearly rate of rupture falls within the range of 1 to 2%.
authors.affiliation: Department of Neurosurgery, University of Washington, Harborview Medical Center, Seattle 98104, USA. hrwinn@u.washington.edu
authors.forename: H Richard
authors.initials: HR
authors.lastname: Winn
authors.forename: John A
authors.initials: JA
authors.lastname: Jane
authors.forename: James
authors.initials: J
authors.lastname: Taylor
authors.forename: Donald
authors.initials: D
authors.lastname: Kaiser
authors.forename: Gavin W
authors.initials: GW
authors.lastname: Britz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017542:Aneurysm, Ruptured / Q000000981:diagnostic imaging / Q000453:epidemiology; D002533:Cerebral Angiography; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D015994:Incidence; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D014768:Virginia / Q000453:epidemiology