title: Inter-rater reliability of published flow diversion occlusion scales.
abstract: BACKGROUND
  With increasing use of flow-diverting stents for the treatment of intracranial aneurysms, standardized methods and a common language to evaluate angiographic outcomes are needed. Multiple grading scales have been developed for this purpose but none has been widely adopted.
  
  
  OBJECTIVE
  To analyze these scales to determine interobserver reliability.
  
  
  METHODS
  Four independent assessors scored the intraprocedural angiograms of patients who underwent flow-diverting stent deployment for an intracranial saccular or fusiform aneurysm at our institution between October 2012 and June 2015. Angiographic outcome immediately after flow-diverting stent deployment was scored using three grading scales (Kamran-Byrne (KB), Simple Measurement of Aneurysm Residual after Treatment (SMART), and O'Kelley, Krings, Marotta (OKM)). Statistical analysis was performed using Light's κ for multiple raters (κ), Kendall's coefficient of concordance (W), and intraclass correlation (ICC).
  
  
  RESULTS
  We included the angiograms of 50 consecutive patients (mean age 58 years, range 30-79) who underwent flow-diverting stent deployment for an intracranial aneurysm (40 saccular, 10 fusiform). Six aneurysms were located in the posterior circulation. The inter-rater reliability was typically poor or fair: SMART aneurysm filling (κ=0.30, W=0.36, ICC=0.12), SMART parent vessel stenosis (κ=0.07, W=0.33, ICC=0.12), KB axis I (κ=0.24, W=0.50, ICC=0.25), KB axis II (κ=0.07, W=0.30, ICC=0.06), OKM aneurysm filling (κ=0.23, W=0.45, ICC=0.13), OKM contrast stasis (κ=0.36,W=0.71, ICC=0.54).
  
  
  CONCLUSIONS
  Existing flow-diverting stent grading scales have low inter-rater reliability for most categories.
authors.affiliation: Department of Neurosurgery, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Marcus D
authors.initials: MD
authors.lastname: Mazur
authors.affiliation: Department of Neurosurgery, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Philipp
authors.initials: P
authors.lastname: Taussky
authors.affiliation: Department of Neuroradiology, Clinical Neurosciences Center, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Lubdha M
authors.initials: LM
authors.lastname: Shah
authors.affiliation: Department of Neuroradiology, Clinical Neurosciences Center, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Blair
authors.initials: B
authors.lastname: Winegar
authors.affiliation: Department of Neurosurgery, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Min S
authors.initials: MS
authors.lastname: Park
keywords: Aneurysm; Angiography; Flow Diverter; Standards