title: Interobserver variability in angiographic measurement and morphologic characterization of intracranial aneurysms: a report from the International Study of Unruptured Intracranial Aneurysms.
abstract: OBJECTIVE
  To determine the variability in assessment of the principal inherent characteristics of intracranial aneurysms through the evaluation of interobserver variability for material with uniform quality.
  
  
  METHODS
  Blinded interpretations of a single set of cerebral arteriograms of 55 aneurysms were evaluated by several statistical approaches.
  
  
  RESULTS
  Excellent correlations were found for the detection and measurement of aneurysms after adjusting for geometric distortion caused by magnification. Progressively decreasing correspondence was found for factors that characterized morphology, including, in order, determination of margins, assessment of accessory appendages, and identification of a neck.
  
  
  CONCLUSIONS
  Correction for geometric distortion was the most critical factor that influenced uniform measurement of size. Standards for measurement and morphologic characteristics were subsequently established for use in the International Study of Unruptured Intracranial Aneurysms.
authors.affiliation: Department of Diagnostic Radiology, Mayo Clinic, Rochester, Minn 55905, USA.
authors.forename: G
authors.initials: G
authors.lastname: Forbes
authors.forename: A J
authors.initials: AJ
authors.lastname: Fox
authors.forename: J
authors.initials: J
authors.lastname: Huston
authors.forename: D O
authors.initials: DO
authors.lastname: Wiebers
authors.forename: J
authors.initials: J
authors.lastname: Torner
mesh_terms: D000328:Adult; D017542:Aneurysm, Ruptured / Q000000981:diagnostic imaging / Q000473:pathology; D002339:Carotid Arteries / Q000000981:diagnostic imaging; D002533:Cerebral Angiography / Q000592:standards / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000473:pathology; D002537:Intracranial Arteriosclerosis / Q000000981:diagnostic imaging; D002538:Intracranial Arteriovenous Malformations / Q000000981:diagnostic imaging; D002546:Ischemic Attack, Transient / Q000000981:diagnostic imaging; D008297:Male; D015588:Observer Variation; D011856:Radiographic Image Enhancement; D011858:Radiographic Magnification; D012189:Retrospective Studies; D016037:Single-Blind Method; D014711:Vertebral Artery / Q000000981:diagnostic imaging