Association Between Carotid Artery Small Plaque on Computed Tomography Angiography and Embolic Stroke of Undetermined Source.

Objectives: While traditionally, carotid plaques with significant stenosis have been considered major embolic sources, recent evidence suggests that even non-stenotic small plaques with a <50% stenosis rate may contribute to cerebral infarction. Herein, we evaluated the relationship between non-stenotic small plaques and embolic stroke of undetermined source (ESUS) using computed tomography angiography (CTA). Materials and Methods: We retrospectively reviewed our single-institutional database of hospitalized patients with stroke between April 2017 and December 2022 and enrolled them with ESUS. We evaluated the presence or absence of non-stenotic carotid artery plaque lesions ipsilateral and contralateral to the cerebral infarction lesion using CTA. A neurologist, blinded to the stroke side and all other clinical information, reviewed each CTA and viewed the axial and sagittal CTA source images. In each image, a line perpendicular to the vessel wall was drawn and the plaque diameter was measured. The largest part was considered as the maximum plaque diameter. Results: A total of 951 patients with stroke were hospitalized during the study period. Among these, 35 patients with unilateral anterior circulation ESUS were enrolled. Plaque prevalence > 3 mm was compared between the carotid artery on the ESUS side and contralateral carotid artery. The prevalences were 31% and 8% on the ESUS and contralateral sides, respectively. Plaques > 3 mm were often found on the ESUS side. Conclusions: Patients with ESUS were more likely to exhibit non-stenotic plaques of ≥3 mm in the infarcted carotid artery than in the contralateral carotid artery. Thus, small non-stenotic plaques may be the embolization source in ESUS, and CT angiography is useful for these evaluations.