Carotid ultrasound is an auxiliary test to check whether the arterial vessels are normal. Among them, carotid ultrasound is an effective method to diagnose and evaluate lesions in the carotid artery wall. Through the color ultrasound, it can clearly show whether there is thickening of the intima and intima in the blood vessels, whether there is plaque formation, the site of plaque formation, size or degree of stenosis, whether there is occlusion, whether there is thrombus in the blood vessels, and whether there is malformation in the blood vessels. Carotid ultrasound examination generally does not require special preparation before the procedure, and the examination is non-invasive, and the patient will not feel any discomfort. Carotid ultrasound may be instructive in detecting diseases such as carotid stenosis, carotid aneurysm, carotid thrombosis, carotid sclerosis, and carotid occlusive sclerosis, as well as assessing the degree of carotid stenosis and assessing whether dizziness and headache are caused by carotid stenosis.