MR-VWI concentric ring sign: a potential imaging feature of internal carotid artery pseudo occlusion and predictive value for successful recanalization

BACKGROUND: Predicting the success of endovascular recanalization in non-acute internal carotid artery occlusion (NICAO) remains a challenge. OBJECTIVE: To examine the hypothesis that the concentric ring sign observed on high-resolution magnetic resonance vessel wall imaging (MR-VWI) could serve as a potential imaging biomarker to improve the accuracy of predicting recanalization success and guide treatment decisions. METHODS: A retrospective analysis was conducted on patients with NICAO who underwent endovascular treatment at our institution between January 2020 and December 2023. Baseline data and details of preoperative digital subtraction angiography (DSA) and MR-VWI, perioperative complications, technical success rates, and follow-up outcomes were collected. A nomogram model was constructed via stepwise regression based on statistically significant variables to predict recanalization success. RESULTS: In total, 63 cases were included in this study. The overall recanalization success rate was 82.5% (52/63), and the periprocedural complication rate was 12.7% (8/63). Stepwise regression identified key predictors, including tapered stumps, occlusion segments ≤4, short occlusion duration, and the C2 concentric ring sign (P<0.05). The resulting nomogram demonstrated excellent predictive capabilities for successful recanalization (area under the curve 0.971). CONCLUSION: The predictive model, integrating MR-VWI and digital subtraction angiography features-including the newly identified 'concentric ring sign'-exhibited excellent predictive performance and clinical usefulness, providing a reliable tool for preoperative evaluation and treatment planning in patients with NICAO.