Diagnostic Performances of the Susceptibility Vessel Sign on MRI for the Prediction of Macroscopic Thrombi Features in Acute Ischemic Stroke

Background and Purpose: The "white" compared to "Red-Black" visual aspect of the thrombus at withdrawal with mechanical thrombectomy (MT) for acute ischemic stroke (AIS) was related to atypical etiologies like infective endocarditis. The susceptibility vessel sign (SVS) and the two-layered SVS (TL-SVS) could help predict outcome and cardio-embolic etiology of AIS. We aim to evaluate the diagnostic performance of the SVS and TLSVS to predict the visual aspect of the thrombus. Materials and Methods: We included patients treated by MT and screened with MRI for the SVS and the TL-SVS for whom thrombus photograph was available. Photographs underwent a double-blind evaluation by neuroradiologists who classified the thrombus as "White" or "Red-Black". Logistic regression assessed the association of Red-Black thrombus and age, sex, baseline National Institutes of Health Stroke Scale, occlusion site, the IVr-tPA administration, SVS and TL-SVS. We calculated the diagnostic performances of the SVS to predict a Red-Black type thrombus. Results: Between May 2017 and July 2018, 139 patients were included in the study. On multivariate analysis, only SVS was an independent predictor for Red-Black thrombus (Odd ratio 8.31, 95%CI2.30 to 32, p value<0.001). Concerning SVS diagnostic performances, the specificity was 0.58 (95%CI0.28 to 0.85), the sensitivity was 0.87 (95%CI0.80 to 0.93), the negative predictive value was 0.30 (95% 0.13 to 0.53), the positive predictive value was 0.96 (95%CI0.90 to 0.99) and accuracy was 0.85 (95%CI0.78 to 0.90). Conclusion: The SVS on MRI provides a good prediction accuracy to anticipate the macroscopic visual aspect of the thrombus after MT for AIS.