Hypertension is an important risk factor for atherosclerosis, and hypertension and atherosclerosis cause damage to the vessel wall of large and medium-sized arteries, which manifests as structural changes such as wall thickening and plaque formation. Examination of superficial vessels such as the carotid artery using high-resolution ultrasound technology can clearly show structural changes in the arterial wall. Carotid artery intima-media thickness (IMT) is the distance between the junction of the mid- and outer-mode of the artery and the junction of the intima and lumen. There is no standardized method for measuring carotid intra-medial thickness, and the posterior wall of the vessel 1 cm before the bifurcation of the common carotid artery is generally chosen to measure the IMT of the carotid artery at the end of diastole.The Chinese Guidelines for the Prevention and Treatment of Hypertension (2005 edition) stipulate that an IMT >= 0.9 mm or the detection of plaque indicates the presence of structural lesions in the patient’s large arteries and is listed as one of the bases for target organ damage. In many large-scale clinical trials, IMT is listed as an observational index reflecting carotid atherosclerosis.