Cerebral infarction is an acute cerebrovascular disease with symptoms of ischemic damage to brain tissue as the main clinical manifestation, which is characterized by high incidence, high disability rate, high mortality rate and high recurrence rate. It seriously endangers the health of patients and affects their quality of life, and also brings heavy medical, economic and social burdens to patients, their families and society. The main cause of cerebral infarction is the narrowing or even occlusion of arterial lumen due to intracranial and/or intracranial atherosclerosis, resulting in localized cerebral tissue ischemia, hypoxia and necrosis. Among them, carotid stenosis in the extracranial segment is often overlooked by patients and even some physicians. According to the literature, 25% of strokes are caused by carotid stenosis. Patients with carotid stenosis of more than 75% have a 2-5% chance of having a stroke in the first year, and if active and effective measures are not taken to improve carotid stenosis, the incidence of stroke in the second year is as high as 13%, which is the cause of frequent cerebral infarction patients. The main factors that induce carotid stenosis are: hypertension, hyperglycemia, hyperlipidemia, overweight, and fatty meat consumption. Clinically, carotid stenosis is divided into two categories, symptomatic and asymptomatic, based on whether it produces cerebral ischemic symptoms. Symptomatic carotid stenosis mainly includes: (1) cerebral ischemic symptoms, which may include tinnitus, vertigo, blackness, blurred vision, dizziness, headache, insomnia, memory loss, drowsiness, and dreaminess. Eye ischemia manifests as vision loss, hemianopia, diplopia, etc. (2) Transient ischemic attack (TIA), the clinical manifestations are transient impairment of sensory or motor function of one limb, transient monocular blindness or aphasia, etc., usually lasting only a few minutes, with complete recovery within 24h after the onset. There is no focal lesion on imaging examination. (3) Ischemic stroke: Common clinical symptoms include sensory impairment of one limb, hemiparesis, aphasia, cerebral nerve damage, and in severe cases, coma, with corresponding neurological signs and imaging features. In contrast, patients with asymptomatic carotid stenosis do not have any clinical signs and symptoms of the nervous system. Sometimes only a weakened or absent carotid artery pulsation is detected during physical examination, and a vascular murmur is heard at the root of the neck or at the carotid artery meridian. The following methods can usually diagnose carotid stenosis: 1. Carotid Doppler ultrasound: Carotid ultrasound is now widely used in clinical medicine for the early diagnosis of ischemic cerebrovascular disease (carotid stenosis) caused by carotid artery lesions, and can detect carotid stenosis in time to choose an effective treatment timing. It has the advantages of being non-invasive, inexpensive and convenient. It is widely used for the initial screening of carotid stenosis. 2.Carotid MRA scan: magnetic resonance carotid angiography (MRA): this method is non-invasive, intuitive, reliable, painless, and can make a clear diagnosis; however, the image quality is poor, and sometimes there are false positives or “exaggerated” stenosis. Carotid MRA with ultrasound can accurately detect more than 95% of patients with high risk of carotid stenosis. 3.Carotid angiography (DSA): It is the most accurate indicator for the diagnosis of carotid stenosis and plaque formation and is considered to be the gold standard. However, the disadvantages are that it is invasive, expensive, and cannot be used in patients with severe cardiopulmonary disease or poor general condition. 4.Carotid CTA: Carotid CT angiography, which is basically non-invasive. For most carotid artery stenosis, carotid CTA is sufficient to meet the needs of examination and diagnosis, especially the introduction of 64-row CT has greatly improved the clarity and confirmation rate of CT angiography. The treatment of carotid stenosis is aimed at improving cerebral blood supply, correcting or relieving the symptoms of cerebral ischemia; preventing TIA and ischemic stroke. Treatment is based on the degree of carotid stenosis and the patient’s symptoms, including medical treatment, surgical treatment and interventional treatment. 1. The purpose of conservative medical treatment is to reduce the symptoms of cerebral ischemia, reduce the risk of stroke, and control the existing diseases such as hypertension, diabetes, hyperlipidemia and coronary heart disease. The main aspects include the following: weight reduction, smoking cessation, limiting alcohol consumption, anti-platelet aggregation therapy: such as aspirin, ticlopidine, etc., improving the symptoms of cerebral ischemia, regular ultrasound examinations, and dynamic monitoring of changes in the disease. 2. The aim of surgical treatment is to prevent the occurrence of stroke and secondly to prevent and slow down the onset of TIA. The standard surgical procedure is carotid endarterectomy (CEA), and in the early 1990s, several large-scale, multicenter clinical trials were conducted to objectively evaluate the effectiveness and safety of CEA, which consistently showed that CEA treatment was more effective than medical drug therapy for symptomatic carotid stenosis, and that patients with 70-99% carotid stenosis benefited significantly from CEA. Although the technique of CEA has been improved, certain complications still occur, including perioperative stroke and death, cerebral nerve injury, wound hematoma infection, postoperative hypertension, and postoperative hyperperfusion syndrome. Percutaneous transluminal angioplasty (PTA) is a relatively mature arterial recanalization technique, which is mainly performed by filling a balloon to squeeze the stenotic segment of the vessel from the inside out, causing fracture damage to the vessel wall and achieving dilation. This technique has been widely used in various vascular diseases throughout the body, such as renal artery, iliac artery, coronary artery, etc. Compared with other vascular diseases, the application of PTA in carotid artery stenosis has progressed slowly because of technical reasons such as the complexity of the PTA operation route, and the fear of complications such as vessel rupture and embolus dislodgement causing cerebral infarction. CAS has the following advantages over CEA: (1) it does not require general anesthesia and can be tolerated by some patients with severe co-morbidities; (2) the lesion may not be limited to the extracranial carotid artery; (3) it is less invasive and takes less time; (4) it can be performed on the carotid, vertebral, and coronary arteries simultaneously. (3) less invasive and shorter operation time; (4) simultaneous treatment of carotid, vertebral and coronary arteries. At present, the success rate of CAS technique is more than 98%, the complication rate is 2-6%, and the mortality rate is less than 1%, which indicates that CAS is safe and effective in treating carotid artery stenosis. The main cause of carotid stenosis is atherosclerosis. Therefore, in order to prevent carotid stenosis, we must first start with the prevention of atherosclerosis. Some data show that the incidence of carotid stenosis in Europeans is much higher than that in Chinese people, which is mainly related to diet. Because Europeans and Westerners their diet is mainly protein, or fat, protein-based, the majority of Chinese people, many people are more vegetarian, may also be related to this. Therefore, it is now believed that carotid stenosis is indeed related to a diet high in fat and sugar. High-fat and high-sugar diets tend to lead to obesity, hypertension, hyperlipidemia and diabetes, and these diseases often become triggering factors for atherosclerosis, which further leads to carotid artery stenosis. Therefore, in order to prevent carotid stenosis, one should eat less high-fat, high-sugar and high-protein foods in daily life, such as fried foods, cakes, chocolates, animal offal, eggs, etc., and eat more low-fat and low-sugar foods such as vegetables. In addition, since middle-aged and elderly people are prone to carotid artery stenosis due to atherosclerosis, middle-aged and elderly people should go to hospitals for regular health checkups to facilitate early detection and prevention of carotid artery stenosis.