Cephalography refers to digital silhouette angiography, which is an invasive imaging test in which the patient needs to enter a catheterization room, have local anesthesia in the groin, and then place a vascular sheath into the femoral artery, and extend the guidewire and catheter through the femoral artery, the aorta, the heart to the great vessels in the neck, all the way to the middle cerebral artery in the brain, where contrast can be injected, followed by segmental visualization with X-ray. This examination is the most delicate examination of the blood vessels in the brain at present, and can accurately show the presence or absence of atherosclerosis, stenosis and occlusion of the blood vessels, clarify the degree of stenosis, and detect the presence or absence of aneurysms and arteriovenous malformations. If the patient has an aneurysm, the aneurysm can be embolized directly during the imaging process, and if there is a stenosis, after evaluation, a vascular stent can also be implanted directly during the imaging process.