@article {Joshi1589, author = {M.D. Joshi and C.J. O{\textquoteright}Kelly and T. Krings and D. Fiorella and T.R. Marotta}, title = {Observer Variability of an Angiographic Grading Scale Used for the Assessment of Intracranial Aneurysms Treated with Flow-Diverting Stents}, volume = {34}, number = {8}, pages = {1589--1592}, year = {2013}, doi = {10.3174/ajnr.A3431}, publisher = {American Journal of Neuroradiology}, abstract = {BACKGROUND AND PURPOSE: 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{\textquoteright}Kelly Marotta grading scale, which was developed specifically for the angiographic assessment of aneurysms treated with flow-diverting stents. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSIONS: 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. OKMO{\textquoteright}Kelly Marotta}, issn = {0195-6108}, URL = {https://www.ajnr.org/content/34/8/1589}, eprint = {https://www.ajnr.org/content/34/8/1589.full.pdf}, journal = {American Journal of Neuroradiology} }