This observational study was designed for the assessment of plaque vulnerability in patients with carotid atherosclerotic stenosis and the development of predictive models for the occurrence and recurrence of atherosclerotic ischemic stroke. The objectives of the study were as follows: first, to integrate the degree of carotid stenosis and plaque characteristics assessed by vascular ultrasound for a comprehensive assessment of plaque vulnerability; second, to develop an assessment tool for the risk of future ischemic stroke in patients with asymptomatic carotid stenosis by combining vascular risk factors, serologic markers, carotid ultrasound characteristics, and contrast-enhanced ultrasonographic parameters; and third, to incorporate vascular ultrasound parameters into existing predictive models of ischemic stroke recurrence risk to develop a risk assessment tool for atherosclerotic ischemic stroke. The main questions it aims to answer are: - How to screen high-risk patients and those eligible for revascularization from asymptomatic carotid stenosis patients for primary prevention of stroke. - How to improve the prediction accuracy of atherosclerotic ischemic stroke based on existing prediction models for secondary prevention of stroke.