The diagnosis of cerebral infarction is based on clinical symptoms and physical signs, and various auxiliary examinations also play a crucial role. The examination items include: 1. Craniocerebral CT: After early diagnosis of cerebral infarction, craniocerebral CT scanning should be carried out firstly in the hospital to exclude the diagnosis of cerebral hemorrhage. When occlusion or stenosis of intracranial or extracranial large arteries is suspected, CT angiography is needed to guide further treatment to see if stenting and endovascular stenting are needed.2. Cranial magnetic resonance imaging (CMRI). Cranial magnetic imaging can be performed within 2 hours of the onset of the disease to find a clear ischemic focus, and magnetic angiography can also be used to assess the patient’s vascular condition at an early stage, to see if there is any serious stenosis or even occlusion of blood vessels, and whether or not to carry out neurological interventions.3. Various laboratory tests. Blood routine, coagulation index, electrolytes, liver and kidney function, etc., can guide intravenous thrombolysis as well as neurointerventional surgery at an early stage.4. Carotid ultrasound as well as transcranial Doppler and other examinations are needed to further assess cranial and cerebral blood flow as well as stenosis of blood vessels. In addition, electrocardiogram, cardiac ultrasound, lower extremity arterial and venous ultrasound and other examinations are also needed.