CT angiographic patterns predict carotid pseudo-occlusion in acute ischemic stroke

Abstract

Background: Identifying carotid pseudo-occlusion (PO) from true occlusion (TO) has implications in determining the candidacy and feasibility of successful endovascular thrombectomy (EVT) in acute ischemic stroke (AIS). Purpose: We reviewed the computed tomography angiographic (CTA) patterns differentiating a PO from a TO and analyzed the rate of successful recanalization after EVT. Materials and Methods: Patients with AIS and proximal internal carotid artery (ICA) occlusion who underwent EVT from 2014 to 2021 were identified. The patterns of carotid occlusion in CTA were classified into beak, dome, and flat patterns and correlated with microcatheter digital subtraction angiography (DSA) as PO and TO. The rates of successful recanalization in PO and TO were analyzed. Results: Of the 24 patients, 16 (66%) had ICA PO and eight (33%) had TO in DSA. A beak pattern of the proximal ICA on CTA was significantly higher among the PO group patients (87.5% vs. 25%, P = 0.005), and a flat pattern was significantly higher among the TO group patients (50% vs. 12%, P = 0.005). A gradual contrast decline of the proximal ICA on CTA images was seen only in PO group patients (85.7% vs. 0%, P = 0.05). There was no significant difference in the rate of successful recanalization between PO and TO group patients (81.25% vs. 62.5%, P = 0.362). Conclusion: Beak pattern and gradual contrast decline at the proximal ICA occlusion site in CTA are suggestive of carotid PO. Identification of PO in CTA can help in planning intervention strategies and prognostication.

Keywords

• acute ischemic stroke
• ct angiogram
• pseudo-occlusion
• true occlusion