Cerebral angiography refers to whole brain vascular digital subtraction angiography, which is performed in an interventional suite with the patient under local anesthesia. After local anesthesia, the patient is punctured through the femoral artery puncture site and a vascular sheath is left in place, after which a catheter and guidewire are inserted from the femoral artery, retrograde up to the heart, then through the heart to the great vessels of the neck and finally to the brain. Through the catheter, a contrast medium is injected into the brain, and the patient’s blood vessels are visualized on the machine through X-ray imaging. After post-processing, digital processing can clearly show all the arterial vessels, and can clarify whether the patient has stenosis, occlusion and the degree of stenosis, and whether there are other diseases such as aneurysms, arteriovenous malformations or cavernous hemangiomas, and smog. If the patient has an occluded blood vessel, it is possible to place a stent directly during the examination.