Prediction of borderzone infarction by CTA in patients undergoing carotid embolization for carotid blowout

BACKGROUND AND PURPOSE: Permanent common carotid artery and/or ICA occlusion is an effective treatment for carotid blowout syndrome. Besides postoperative thromboembolic infarction, permanent common carotid artery and/or ICA occlusion may cause borderzone infarction when the collateral flow to the deprived brain territory is inadequate. In this study, we aimed to test the predictive value of CTA for post-permanent common carotid artery and/or ICA occlusion borderzone infarction in patients with carotid blowout syndrome. MATERIALS AND METHODS: In this retrospective study, we included 31 patients undergoing unilateral permanent common carotid artery and/or ICA occlusion for carotid blowout syndrome between May 2009 and December 2016. The vascular diameter of the circle of Willis was evaluated using preprocedural CTA, and the risk of borderzone infarction was graded as very high risk, high risk, intermediate risk, low risk, and very low risk. RESULTS: The performance of readers' consensus on CTA for predicting borderzone infarction was excellent, with an area under receiver operating characteristic curve of 0.938 (95% confidence interval, 0.85-1.00). We defined very high risk, high risk, and intermediate risk as positive for borderzone infarction, the sensitivity, specificity, positive predictive value, and negative predictive value of CTA for borderzone infarction were 100% (7/7), 62.5% (15/24), 43.8% (7/16), and 100% (15/15), respectively. The interobserver reliability was excellent ( 0.807). No significant difference in the receiver operating characteristic curves was found between the 2 readers (P .114). CONCLUSIONS: CTA can be used to predict borderzone infarction after permanent common carotid artery and/or ICA occlusion by measuring the collateral vessels of the circle of Willis.