title: Prevalence of unruptured intracranial aneurysm on MR angiography.
abstract: OBJECTIVE
  To evaluate the prevalence of incidentally found unruptured intracranial aneurysms (UIAs) on the brain MR angiography (MRA) from a community-based general hospital.
  
  
  METHODS
  This was a prospectively collected retrospective study, carried out from January 2004 to December 2004. The subjects included 3049 persons from a community-based hospital in whom MRA was performed according to a standardized protocol in an outpatient setting. Age- and sex-specific prevalence of UIAs was calculated. The results by MRA were compared with intra-arterial digital subtraction angiography (DSA) findings.
  
  
  RESULTS
  Unruptured intracranial aneurysms were found in 137 (5%) of the 3049 patients (M:F = 43:94; mean age, 60.2 years). The prevalence of UIAs was 5% (n = 94) in women and 4% (n = 43) in men, respectively (p = 0.2046) and showed no age-related increase. The most common site of aneurysm was at the distal internal carotid artery (n = 64, 39%), followed by the middle cerebral artery (n = 40, 24%). In total, 99% of aneurysms measured less than 12 mm, and 93% of aneurysms measured less than 7 mm. Direct comparisons between MRA and DSA were available in 70 patients with 83 UIAs; the results revealed two false positive and two false negative results.
  
  
  CONCLUSIONS
  This community-hospital based study suggested a higher prevalence of UIAs observed by MRA than previously reported. These findings should be anticipated in the design and use of neuroimaging in clinical practice.
authors.affiliation: Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, Korea.
authors.forename: Tae Yeon
authors.initials: TY
authors.lastname: Jeon
authors.forename: Pyoung
authors.initials: P
authors.lastname: Jeon
authors.forename: Keon Ha
authors.initials: KH
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017542:Aneurysm, Ruptured / Q000175:diagnosis; D015901:Angiography, Digital Subtraction; D002533:Cerebral Angiography; D005260:Female; D006801:Humans; D033162:Incidental Findings; D002532:Intracranial Aneurysm / Q000175:diagnosis* / Q000000981:diagnostic imaging; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D055815:Young Adult