Increased density of the middle cerebral artery may be the result of cerebral infarction, hypertension, or atherosclerosis. Increased density of the middle cerebral artery is a manifestation of the dense arterial sign shown on CT imaging of the brain. Dense arterial sign is an increase in the density of a section or segment of the middle cerebral artery, vertebral artery, internal carotid artery, and other large arteries, and the average value of the CT measurement is about 60~90 Hu. Increased density of the middle cerebral artery is mainly seen in cerebral infarction, but can also be seen in hypertension and atherosclerosis. 1. Cerebral infarction: Increased density of middle cerebral artery is a precursor of cerebral infarction or a concurrent manifestation of cerebral infarction, due to cerebral tissue ischemia, hypoxia, necrosis and so on, cerebral artery blockage, resulting in cerebral infarction with high density of the components, which represents the middle cerebral artery lumen of the blood clots thrombus, early diagnosis of cerebral infarction and treatment has certain significance. 2. Hypertension: a disease characterized by elevated arterial pressure. Atherosclerosis occurs in hypertension, which can lead to thickening of the arterial wall, so the density of the middle cerebral artery increases along with it, resulting in elevated blood pressure. 3. Atherosclerosis: high cholesterol is a risk factor for cerebrovascular disease, high cholesterol in the blood can cause atherosclerosis, plaque in the blood vessels and the blood becomes viscous, resulting in narrowing of the blood vessels, occlusion, CT manifestation of increased density of the middle cerebral artery. Increased density of the middle cerebral artery is related to many reasons, and it is necessary to consult a doctor in time to identify the cause and treat the symptoms.