Angiography is an x-ray projection technique in which contrast is injected directly into the blood vessels to visualize the cerebrovascular system. Angiography can specifically understand the morphological changes of blood vessels, such as travel, distribution, displacement, thickness and changes in circulation time. The final determination of whether the lesion is a blood vessel itself or a lesion in other parts of the skull causing vascular changes provides the basis for clinical diagnosis and treatment. Indications: ①Intracranial vascular diseases, such as intracranial aneurysm, arteriovenous malformation, arteriovenous fistula, arterial embolism, etc. ②Intracranial occupying lesions, such as intracranial tumors, abscesses, cysts, hematomas, etc. ③Extracerebral hematoma caused by cranial trauma. ④Observation of surgical effect and cerebral blood circulation status after surgery. Contraindications: ①Caution is needed for those with senile arteriosclerosis. ②People with severe cardiac, renal and hepatic insufficiency. ③Those who are allergic to contrast media. ④Patients with severe bleeding tendency.