SWI Susceptibility Vessel Sign in Patients Undergoing Mechanical Thrombectomy for Acute Ischemic Stroke.

BACKGROUND AND PURPOSE: The frequency and clinical significance of the susceptibility vessel sign in patients with acute ischemic stroke remains unclear. We aimed to assess its prevalence in patients with acute ischemic stroke undergoing mechanical thrombectomy and to analyze its association with interventional and clinical outcome parameters in that group. MATERIALS AND METHODS: Six hundred seventy-six patients with acute ischemic stroke and admission MR imaging were reviewed retrospectively. Of those, 577 met the eligibility criteria for further analysis. Imaging was performed using a 1.5T or 3T MR imaging scanner. Associations between baseline variables, interventional and clinical outcome parameters, and susceptibility vessel sign were determined with multivariable logistic regression models. Results are shown as adjusted ORs with 95% CIs. RESULTS: The susceptibility vessel sign was present in 87.5% (n = 505) of patients and associated with tandem occlusion (adjusted OR, 3.3; 95% CI, 1.1–10.0; P = .032) as well as successful reperfusion, defined as an expanded TICI score of ≥2b (adjusted OR, 2.4; 95% CI, 1.28–4.6; P = .007). The susceptibility vessel sign was independently associated with functional independence (mRS ≤ 2: adjusted OR, 2.1; 95% CI, 1.1–4.0; P = .028) and lower mortality (adjusted OR, 0.4; 95% CI, 0.2–0.7; P = .003) at 90 days, even after adjusting for successful reperfusion. The susceptibility vessel sign did not influence the number of passes performed during mechanical thrombectomy, the first-pass reperfusion, or the risk of peri- or postinterventional complications. CONCLUSIONS: The susceptibility vessel sign is an MR imaging phenomenon frequently observed in patients with acute ischemic stroke and is associated with successful reperfusion after mechanical thrombectomy. However, superior clinical functional outcome and lower mortality noted in patients showing the susceptibility vessel sign could not be entirely attributed to higher reperfusion rates.