For patients with acute cerebrovascular disease, it is necessary to determine the diagnosis and understand the problems related to its onset, treatment, prognosis and comorbidities, etc. The following tests are usually done: 1. 2.Cerebrospinal fluid examination If subarachnoid hemorrhage is suspected and no abnormality is seen on brain CT, lumbar puncture can be performed. Cerebrospinal fluid pressure should be measured and sent for routine cerebrospinal fluid and cytology examination. 3. Special examinations 1) Brain CT examination is preferred for timely diagnosis of hemorrhage or infarction; location and extent of hematoma or infarction; 2) Cerebral angiography or digital subtraction cerebral angiography (DSA) is preferable for understanding cerebral vascular stenosis or occlusion, etiology of subarachnoid hemorrhage, and preparing for interventional or surgical treatment; brain CTA or MRA can also be selected for screening first. 3) Brain MRI examination, which shows more clearly in patients with cerebral infarction, should be preferred for suspected cerebellar and brainstem lesions. 4) If necessary, transcranial Doppler and local cerebral blood flow (rCBF) measurement are feasible.