Distinction between acute and chronic carotid disease based on computed tomography angiography in acute ischemic stroke patients with carotid artery occlusion

Prompt endovascular thrombectomy is crucial for patients with acute ischemic stroke due to internal carotid artery (ICA) occlusion. However, distinguishing acute from chronic carotid disease can be challenging. This study investigates the utility of initial CT angiography (CTA) findings in differentiating acute and chronic ICA disease among acute cerebral infarction patients with ICA occlusion. We conducted a retrospective analysis of CTA data from acute stroke patients with apparent ICA occlusion at a single stroke center. Patients were categorized into acute and chronic groups based on clinical information, mechanical thrombectomy outcomes, and infarct patterns. We compared CTA findings between the groups, focusing on occlusion site and carotid atherosclerosis burden. Between January 2016 and June 2021, 42 patients were included in the study (28 acute; 14 chronic). The acute group had a significantly higher proportion of tapering patterned proximal occlusion compared to the chronic group. Patients with chronic ICA disease were more likely to have stump patterned proximal occlusion and advanced atherosclerotic burden in the contralateral proximal ICA. The carotid occlusion imaging score, comprising occlusion pattern and atherosclerosis burden, demonstrated good performance in discriminating chronic carotid disease from acute carotid occlusion (area under the receiver operating curve = 0.94, 95% confidence interval = 0.87–1.00, p < 0.001). The occlusion shape of the ipsilateral ICA and the atherosclerotic burden of the contralateral ICA can aid in differentiating chronic carotid disease from acute ICA occlusion among acute stroke patients with ICA occlusion.