1.What is cerebral angiography? Cerebral angiography is a method to diagnose cerebrovascular diseases by injecting iodine-containing contrast agent into the blood vessels through a catheter to visualize cerebrovascular vessels, and to clearly display the morphology of cerebrovascular vessels through DSA machine with rapid and continuous film taking and photo processing. It is the most advanced cerebrovascular treatment method and the gold standard for the diagnosis of cerebrovascular diseases. Cerebral angiography can not only show the morphological changes of the blood vessels themselves, such as dilatation, malformation, spasm, stenosis, vascular occlusion, hemorrhage, etc., but also determine the presence or absence of occupancy according to the changes in the location of the blood vessels. Therefore, it has special significance for the diagnosis of intracranial vascular lesions, and can be said to be the “gold standard” for the diagnosis of cerebrovascular diseases. In recent years, with the wide application of CT and MRI and the development of vascular imaging technology, some intracranial occupying lesions and peripheral vascular lesions are examined by CT or MRI. However, these examinations still cannot replace cerebral angiography in many aspects, such as patients with subarachnoid hemorrhage, which is often due to intracranial aneurysm or vascular malformation. For smaller diameter aneurysms, CT and MRI angiography may not be able to show them, and once they are missed, the consequences are serious. In order to make a clear diagnosis and consider surgery, cerebral angiography is required. A cerebral angiogram will clarify whether the aneurysm is an intracranial aneurysm or a vascular malformation. It can also determine the location, size and number of aneurysms, or the location, shape, blood supply and collateral circulation of vascular malformations, etc., and can provide timely treatment if problems are found. However, cerebral angiography is an invasive test, which is not fully applicable to some patients. Therefore, it should be chosen carefully according to the different conditions of patients. 2.Which patients should have cerebral angiography? (1) Patients with cerebral infarction, transient ischemic attack and vertigo; (2) Patients with vascular stenosis or occlusion considered by color ultrasound of neck vessels or transcranial Doppler ultrasound (TCD); (3) Patients with cerebral vascular stenosis, occlusion, aneurysm, arteriovenous malformation and arteriovenous fistula suggested by magnetic resonance or CT angiography; (4) Patients with subarachnoid hemorrhage, cerebral hemorrhage or ventricular hemorrhage; (5) Patients with CT or MRI suggesting the possibility of smog; (6) Patients with acute ischemic cerebrovascular disease requiring arterial thrombolysis; (7) Patients considering acute ophthalmic artery occlusion; (8) Patients with suspected intracranial venous sinus thrombosis; (9) Patients with headache with cerebral tinnitus, unilateral erogenous proptosis, unilateral arteriovenous nerve palsy, and other patients considering cerebrovascular disease with negative conventional tests; (10) Patients with brain tumors to be surgically removed; (11) Patients with other blood flow-rich lesions on the head and face before resection.