title: Interobserver variability in the characterization of giant intracranial aneurysms with special emphasis on aneurysm diameter and shape.
abstract: BACKGROUND
  The Giant Intracranial Aneurysm Registry is a multicenter observational trial exclusively focusing on giant intracranial aneurysms (GIA). As no data exist on the interobserver variability in the radiological description of GIA, there is some uncertainty concerning the reliability of the GIA characteristics included in the registry. We have therefore designed a study to test the interobserver variability in the description of the specific GIA characteristics that are examined in the GIA registry.
  
  
  METHODS
  Six different raters analyzed imaging of five GIA concerning GIA location, GIA size, GIA shape, GIA thrombosis, and the presence of perianeurysmal edema. Interobserver variability was examined using intraclass correlation and Fleiss' kappa analysis.
  
  
  RESULTS
  The intraclass correlation coefficient was 0.99 (95 % CI 0.97-1.0) for the largest GIA diameter and 0.98 (95 % CI 0.94-1.0) for the largest GIA diameter in an axial imaging slice. We found perfect interobserver agreement (Fleiss' kappa 1.00) in the characterization of GIA location and the presence of perianeurysmal edema and almost perfect interobserver agreement for GIA thrombosis (Fleiss' kappa 0.86, 95 % CI 0.63-1.00). Only moderate interobserver agreement was found in the description of GIA shape (Fleiss' kappa 0.50, 95 % CI 0.27-0.73).
  
  
  CONCLUSIONS
  While GIA size, location, thrombosis, and the presence of perianeurysmal edema showed excellent interobserver agreement, the description of GIA shape was achieved with only moderate agreement. Data on GIA shape in multicenter studies, like the GIA registry, should therefore be discussed with caution and potentially reassessed in a centralized fashion.
authors.affiliation: Department of Neurosurgery, Technical University of Munich, Munich, Germany.
authors.forename: Maria
authors.initials: M
authors.lastname: Wostrack
authors.affiliation: Department of Neurosurgery, Georg-August-University Goettingen, Göttingen, Germany.
authors.forename: Dorothee
authors.initials: D
authors.lastname: Mielke
authors.affiliation: Department of Neurosurgery, Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Kato
authors.affiliation: Department of Neurosurgery, University of Greifswald, Greifswald, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Guhl
authors.affiliation: Department of Neurosurgery, University Medical Center, Hamburg Eppendorf, Germany.
authors.forename: Nils Ole
authors.initials: NO
authors.lastname: Schmidt
authors.affiliation: Department of Neurosurgery, Charité - Universitaetsmedizin Berlin, Campus Virchow Klinikum, Augustenburger Platz 1, 13353, Berlin, Germany.
authors.forename: Nicolai
authors.initials: N
authors.lastname: Maldaner
authors.affiliation: Department of Neurosurgery, Charité - Universitaetsmedizin Berlin, Campus Virchow Klinikum, Augustenburger Platz 1, 13353, Berlin, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Vajkoczy
authors.affiliation: Department of Neurosurgery, Charité - Universitaetsmedizin Berlin, Campus Virchow Klinikum, Augustenburger Platz 1, 13353, Berlin, Germany. julius.dengler@charite.de.
authors.forename: Julius
authors.initials: J
authors.lastname: Dengler
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000473:pathology*; D018810:Magnetic Resonance Angiography / Q000592:standards*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results
keywords: Giant intracranial aneurysm; Interobserver variability; Neurovascular imaging; Partially thrombosed intracranial aneurysm