CTA Identifies Non-stenotic Extracranial Plaque Features Susceptible to Stroke.

Objective: To evaluate the association between CTA-derived plaque features and composition and ipsilateral embolic stroke of undetermined source (ESUS) in patients with non-stenotic (<50%) extracranial carotid atherosclerosis.

Methods: Patients with acute neurological symptoms who underwent head and neck CTA between May 2021 and May 2024 were retrospectively enrolled. Those with non-stenotic extracranial carotid plaques were included, comprising individuals with anterior circulation ESUS and controls without ESUS. Plaque morphology and compositional profiles were assessed.

Results: A total of 161 carotid arteries were analyzed, including 70 ipsilateral to an ESUS and 91 from controls. Morphological features of non-stenotic carotid plaques differed significantly between the ESUS and control groups. Plaque subcomponent volumes were quantified by using 3D Slicer software and the relative proportions of lipid, fibrous, and calcified components differed significantly between groups. Multivariate analysis identified internal carotid artery (ICA) and common carotid artery (CCA) diameters, positive remodeling (PR), and a smaller calcification volume percentage as independent predictors of ESUS [odds ratio (OR): 8.37, P = 0.015; OR: 4.50, P < 0.001; OR: 0.23, P = 0.008]. A nomogram incorporating these factors demonstrated predictive utility for ESUS risk.

Conclusions: CTA-derived characteristics of non-stenotic carotid plaques effectively identified plaque features associated with ESUS. Larger ICA and CCA diameters, PR, and reduced calcification volume percentage were independent predictors of high-risk plaques. These findings can refine risk stratification and help guide individualized therapeutic strategies.