RT Journal Article SR Electronic T1 Interobserver Variability in Retreatment Decisions of Recurrent and Residual Aneurysms JF American Journal of Neuroradiology JO Am. J. Neuroradiol. FD American Society of Neuroradiology DO 10.3174/ajnr.A3326 A1 J.S. McDonald A1 R.E. Carter A1 K.F. Layton A1 J. Mocco A1 J.B. Madigan A1 R.G. Tawk A1 R.A. Hanel A1 S.S. Roy A1 H.J. Cloft A1 A.M. Klunder A1 S.H. Suh A1 D.F. Kallmes YR 2012 UL http://www.ajnr.org/content/early/2012/10/25/ajnr.A3326.abstract AB BACKGROUND AND PURPOSE: The degree of variation in retreatment decisions for residual or recurrent aneurysms among endovascular therapists remains poorly defined. We performed a multireader study to determine what reader and patient variables contribute to this variation. MATERIALS AND METHODS: Seven endovascular therapists (4 neuroradiologists, 3 neurosurgeons) independently reviewed 66 cases of patients treated with endovascular coil embolization for ruptured or unruptured aneurysm. Cases were rated on a 5-point scale recommending for whether to retreat and a recommended retreatment type. Reader agreement was assessed by intraclass correlation coefficient and by identifying cases with a “clinically meaningful difference” (a difference in score that would result in a difference in treatment). Variables that affect reader agreement and retreatment decisions were examined by using the Wilcoxon signed-rank test, Pearson χ2 test, and linear regression. RESULTS: Overall interobserver variability for decision to retreat was moderate (ICC = 0.50; 95% CI, 0.40–0.61). Clinically meaningful differences between at least 2 readers were present in 61% of cases and were significantly more common among neuroradiologists than neurosurgeons (P = .0007). Neurosurgeons were more likely to recommend “definitely retreat” than neuroradiologists (P < .0001). Previously ruptured aneurysms, larger remnant size, and younger patients were associated with more retreat recommendations. Interobserver variability regarding retreatment type was fair overall 0.25 (95% CI, 0.14–0.41) but poor for experienced readers 0.14 (95% CI, 0–0.34). CONCLUSIONS: There is a large amount of interobserver variability regarding the decision to retreat an aneurysm and the type of retreatment. This variability must be reduced to increase consistency in these subjective outcome measurements. Abbreviations CIconfidence intervalICCintraclass correlation coefficientIQRinterquartile rangemRSmodified Rankin Scale