Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada.
AJNR Am J Neuroradiol. 2013 Aug;34(8):1589-92. doi: 10.3174/ajnr.A3431. Epub 2013 Feb 28.
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.
新型颅内动脉瘤血流导向支架治疗后的血管造影分级标准已经研发出来，因为之前的血管造影分级标准不能应用于这些动脉瘤。本研究的目的是评估新型 O'Kelly Marotta 分级标准的观察者内和观察者间的可变性，该分级标准是专门为评估血流导向支架治疗后的动脉瘤而开发的。
神经放射学和神经外科学科的多名观察者（n = 31）分别对 14 个接受腔内血流分流器治疗的动脉瘤的治疗前后的血管造影图像进行评估。要求观察者使用 OKM 分级标准对治疗前后的血管造影进行分类。随后通过计算广义多观察者 κ 统计量评估观察者内和观察者间的可变性，并通过进行 Wilcoxon 符号秩和检验评估组间差异，进行统计分析。
OKM 分级标准的变异性分析分别产生了可观（κ = 0.74）和近乎完美（κ = 0.99）的观察者内和观察者间一致性，神经放射学背景与神经外科学背景的观察者、主治医生与受训者之间没有统计学上的显著差异。
新型颅内动脉瘤血流导向支架治疗后的血管造影分级标准 OKM 是一种可靠的分级标准，不同背景和培训水平的使用者均可平等地使用。与现有的血管造影分级标准的观察者间变异性比较显示，该分级标准具有同等或更好的性能。
