title: Interobserver variability in the assessment of aneurysm occlusion with the WEB aneurysm embolization system.
abstract: OBJECTIVE
  The WEB (WEB aneurysm embolization system, Sequent Medical, Aliso Viejo, California, USA) is a self-expanding, nitinol, mesh device designed to achieve aneurysm occlusion after endosaccular deployment. The WEB Occlusion Scale (WOS) is a standardized angiographic assessment scale for reporting aneurysm occlusion achieved with intrasaccular mesh implants. This study was performed to assess the interobserver variability of the WOS.
  
  
  METHODS
  Seven experienced neurovascular specialists were trained to apply the WOS. These physicians independently reviewed angiographic image sets from 30 patients treated with the WEB under blinded conditions. No additional clinical information was provided. Raters graded each image according to the WOS (complete occlusion, residual neck or residual aneurysm). Final statistics were calculated using the dichotomous outcomes of complete occlusion or incomplete occlusion. The interobserver agreement was measured by the generalized κ statistic.
  
  
  RESULTS
  In this series of 30 test case aneurysms, observers rated 12-17 as completely occluded, 3-9 as nearly completely occluded, and 9-11 as demonstrating residual aneurysm filling. Agreement was perfect across all seven observers for the presence or absence of complete occlusion in 22 of 30 cases. Overall, interobserver agreement was substantial (κ statistic 0.779 with a 95% CI of 0.700 to 0.857).
  
  
  CONCLUSIONS
  The WOS allows a consistent means of reporting angiographic occlusion for aneurysms treated with the WEB device.
authors.affiliation: Stony Brook University Medical Center, Stony Brook, New York, USA.
authors.forename: David
authors.initials: D
authors.lastname: Fiorella
authors.affiliation: Semmes-Murphy Clinic, Memphis, Tennessee, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: Arthur
authors.affiliation: Oxford University Neurovascular and Neuroradiology Research Unit, Oxford, UK.
authors.forename: James
authors.initials: J
authors.lastname: Byrne
authors.affiliation: Hôpital Maison-Blanche, Université Reims-Champagne-Ardenne, Reims, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Pierot
authors.affiliation: Oxford University Neurovascular and Neuroradiology Research Unit, Oxford, UK.
authors.forename: Andy
authors.initials: A
authors.lastname: Molyneux
authors.affiliation: Department of Interventional Neuroradiology, UCLA, Los Angeles, California, USA.
authors.forename: Gary
authors.initials: G
authors.lastname: Duckwiler
authors.affiliation: Sequent Medical, Inc, Aliso Viejo, California, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: McCarthy
authors.affiliation: University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA.
authors.forename: Charles
authors.initials: C
authors.lastname: Strother
mesh_terms: D002533:Cerebral Angiography / Q000592:standards*; D004621:Embolization, Therapeutic / Q000295:instrumentation / Q000592:standards*; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000628:therapy*; D008297:Male; D000069471:Neurosurgeons / Q000592:standards*; D015588:Observer Variation; D016037:Single-Blind Method
keywords: Aneurysm; Angiography; Flow Diverter