title: Incidence of growth and rupture of unruptured intracranial aneurysms followed by serial MRA.
abstract: BACKGROUND
  The natural history, including growth and rupture, of unruptured intracranial aneurysms (UIAs) remains unknown. Here, we present the results of serial magnetic resonance angiography (MRA) follow-up study in 111 patients with 136 UIAs.
  
  
  METHODS
  A total of 111 patients with 136 UIAs were followed annually over the past 12 years, using 1.5-Tesla MRA. Follow-up was ended when UIAs were treated surgically, or the patients died of subarachnoid hemorrhage or other causes. Various factors influencing aneurysm rupture or growth were examined statistically.
  
  
  RESULTS
  Aneurysm rupture and growth occurred in six and 13 of the 111 patients, respectively. Annual rupture rate was 1.8 % per year and annual growth rate was 3.9 % per year. Aneurysm size was the sole factor influencing rupture(H.R. 1.214, 95 % CI, 1.078-1.368) and multiplicity was the sole factor influencing aneurysm growth (H.R. 5.174, 95 % CI 1.81-14.80).
  
  
  CONCLUSIONS
  Serial MRA study showed that the incidence of UIA growth was twice as high as that of UIA rupture. As four patients showed aneurysm rupture or growth within 1 year, further investigations are necessary to determine the optimum interval of radiological investigation and to identify which UIAs grow or rupture within a short time.
authors.affiliation: Department of Neurosurgery, Iseikai Hospital, 6-2-25, Sugawara Higashi Yodogawa-ku, Osaka City, Osaka, 533-0022, Japan. BYX05641@nifty.ne.jp
authors.forename: K
authors.initials: K
authors.lastname: Matsumoto
authors.forename: S
authors.initials: S
authors.lastname: Oshino
authors.forename: M
authors.initials: M
authors.lastname: Sasaki
authors.forename: K
authors.initials: K
authors.lastname: Tsuruzono
authors.forename: S
authors.initials: S
authors.lastname: Taketsuna
authors.forename: T
authors.initials: T
authors.lastname: Yoshimine
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017542:Aneurysm, Ruptured / Q000175:diagnosis* / Q000453:epidemiology* / Q000628:therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D002532:Intracranial Aneurysm / Q000150:complications* / Q000175:diagnosis* / Q000628:therapy; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D020380:Needs Assessment; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors