Ischemic stroke is a significant cause of death and disability. Embolic Stroke of Undetermined Source (ESUS) accounts for a large proportion of acute ischemic strokes. A clear etiology is crucial for the treatment and prevention of stroke. The pathogenic mechanism of non-stenotic carotid plaque (NSCP) in ESUS is not yet fully understood. This study used computed tomographic angiography (CTA) to assess the correlation between NSCP and ESUS.