Factors in the pathogenesis of cerebral watershed infarction: hemodynamic changes: hypotension, low circulating blood volume. Cerebral watershed infarction, also known as marginal zone infarction, is an infarction caused by limited ischemia in the marginal zone of two adjacent arterial blood supply areas, and its incidence accounts for 2%-3% of cerebrovascular disease and 5% of ischemic cerebrovascular disease. The incidence of CWI in China is 2.6%-16.6%, and it is common in the marginal zone of the intracranial blood supply area of large vessels, and occasionally in the brain tissue between the blood supply area of two cerebellar arteries and the marginal zone of the blood supply area of the anterior and posterior spinal arteries and the root artery. It is most common in cases of syncope, shock, cardiac arrhythmia, cardiac arrest, cardiac surgery, improper use of antihypertensive drugs and anesthetics, etc. After a sudden drop in blood pressure that lasts for a certain period of time, vascular occlusion occurs due to slow blood flow, stagnation, and aggregation of platelets and fibrin, resulting in CWI with mostly bilateral, symmetrical lesions of carotid stenosis or occlusion. When the cross-sectional area of the vessel is reduced by 50% or more, the distal pressure of the vessel is affected, and CWI is more likely to occur when combined with a decrease in systemic blood pressure, hemodynamic disturbances, or incompetent collateral circulation. Microembolism: Embolic sources: cardiogenic, vascular, cancer emboli, cholesterol crystals, etc. Posterior communicating anatomical variant ipsilateral posterior communicating artery diameter >1mm protects cerebral perfusion from CWI; if ipsilateral posterior communicating artery diameter