Cerebrovascular

Cerebrovascular refers to the blood vessels that supply the brain and the circulatory processes that maintain cerebral perfusion. The cerebrovascular system includes the anterior circulation from the internal carotid arteries and the posterior circulation from the vertebrobasilar system, which join via the circle of Willis to provide collateral flow. Blood is drained by cerebral veins into dural sinuses and the systemic venous system. The brain relies on autoregulation to keep a relatively constant blood flow across a range of pressures.

Common cerebrovascular disorders include stroke, defined as acute brain injury caused by reduced or interrupted blood flow or by bleeding. Ischemic stroke, due to arterial occlusion, accounts for the majority of cases, while hemorrhagic stroke includes intracerebral and subarachnoid hemorrhages. Transient ischemic attack is a brief episode of focal neurological dysfunction due to transient ischemia. Other conditions affecting the cerebrovascular system include intracranial aneurysms, arteriovenous malformations, moyamoya disease, and cerebral vasculitis. Risk factors overlap with cardiovascular disease and include hypertension, atherosclerosis, diabetes, atrial fibrillation, smoking, and advancing age.

Diagnosis relies on clinical assessment and imaging. Noncontrast CT is often used initially to identify bleeding; MRI provides detailed tissue information. Vascular imaging (CT angiography, MR angiography, Doppler ultrasound) assesses vessel patency and plaques. In selected cases, catheter angiography is performed.

Treatment emphasizes rapid reperfusion for ischemic stroke, with intravenous thrombolysis within a limited time window and mechanical thrombectomy for large vessel occlusion. Hemorrhagic stroke management focuses on blood pressure control and reversal of coagulopathy, with surgical interventions as needed. Secondary prevention includes antiplatelet therapy after ischemic events, anticoagulation for atrial fibrillation, statins, risk-factor modification, and rehabilitation to improve function.