Carotid plaque is divided into two types, namely hard plaque and soft plaque. In comparison, carotid soft plaque is more dangerous, the risk is mainly that soft plaque is unstable, easy to rupture and fall off. Once the plaque is ruptured and dislodged, it will move with the blood circulation and lead to blockage of other blood vessels, which can block the blood vessels of important organs, such as the blockage of cerebral vessels, i.e. the formation of cerebral embolism. The harm caused by cerebral embolism is stroke, which can lead to paralysis or even coma. A small risk of dislodging a hard carotid plaque is suggestive of carotid atherosclerosis, which may be combined with systemic atherosclerotic disease.