Observer variability of an angiographic grading scale used for the assessment of intracranial aneurysms treated with flow-diverting stents

• Published in: American journal of neuroradiology : AJNR Vol. 34; no. 8; pp. 1589 - 1592
• Main Authors: Joshi, M D, O'Kelly, C J, Krings, T, Fiorella, D, Marotta, T R
• Format: Journal Article
• Language: English
• Published: United States American Society of Neuroradiology 01.08.2013
• Subjects: Blood Vessel Prosthesis; Cerebral Angiography - methods; Humans; Interventional; Intracranial Aneurysm - diagnostic imaging; Intracranial Aneurysm - surgery; Observer Variation; Reproducibility of Results; Sensitivity and Specificity; Severity of Illness Index; Stents; Treatment Outcome
• ISSN: 0195-6108; 1936-959X
• DOI: 10.3174/ajnr.A3431

Novel angiographic grading scales for the assessment of intracranial aneurysms treated with flow-diverting stents have been recently developed because previous angiographic grading scales cannot be applied to these aneurysms. The purpose of this study was to evaluate the inter- and intraobserver variability of the novel O'Kelly Marotta grading scale, which was developed specifically for the angiographic assessment of aneurysms treated with flow-diverting stents. Multiple raters (n = 31) from the disciplines of neuroradiology and neurosurgery were presented with pre- and posttreatment angiographic images of 14 aneurysms treated with intraluminal flow diverters. Raters were asked to classify pre- and posttreatment angiograms by using the OKM grading scale. Statistical analyses were subsequently performed with calculation of a generalized multirater κ statistic for assessment of inter- and intraobserver variability and by performing a Wilcoxon signed rank sum test for assessment of group differences. Variability analysis of the OKM grading scale yielded substantial (κ = 0.74) and almost perfect (κ = 0.99) inter- and intraobserver agreement, respectively, with no statistically significant differences between raters with a background of neuroradiology versus neurosurgery or attending physician versus trainee. The OKM grading scale for the assessment of intracranial aneurysms treated with flow-diverting stents is a reliable grading scale that can be used equally well by users of varying backgrounds and levels of training. Comparison with interobserver variability of pre-existing angiographic grading scales shows equal or better performance.