Head imaging 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 a vascular sheath is placed into the femoral artery, and a guidewire and catheter are inserted through the femoral artery, aorta, and heart to the great vessels of the neck, and all the way down to the brain at the middle cerebral artery, where the contrast agent can be injected, and then X-rays can be used for segmental visualization. This examination is the most delicate examination of the blood vessels in the brain, and can accurately show the presence or absence of atherosclerosis, stenosis and occlusion of the blood vessels, clarify the degree of stenosis, and can detect the presence or absence of aneurysms and arteriovenous malformations. If the patient has an aneurysm, the aneurysm can be directly embolized during the imaging process, and if there is stenosis, stenting can also be done directly during the imaging process after evaluation.