Risk The risk may vary depending on the nature of the pathology of the disease being examined and the experience of the angiography team. The overall risk of complications causing permanent nerve damage is 0.1%. For asymptomatic carotid stenosis studies, there is a 1.2% chance of complications. In general: non-vascular deep lesions cause structural changes in veins and surface lesions cause structural changes in arteries. Malignant tumors (e.g., glioblastoma) typically present with premature venous reflux. Meningiomas “come fast and stay long”. Allcock test Compression of the common carotid artery during vertebral arteriography is used to evaluate blood flow through the posterior communicating artery. To help locate the middle meningeal artery during external carotid arteriography, it can be sought at the anterior border of the pterygoid sinus airspace. Intraoperative cerebral angiography is mainly used in aneurysm surgery to determine whether the aneurysm is completely clamped and the patency of the aneurysm-carrying artery, and in AVM surgery to determine whether the resection is complete. 1. Use conventional iodine enhancer as well as C-arm. A head frame that transmits X-rays is required, and the femoral sheath is preserved for intraoperative application during preoperative angiography. 2. Indocyanine green: can be seen in visible light, shows more clearly after excitation with near-infrared light, and can only be used in superficial vessels. It may not show well in wide carotid aneurysms or vessels with severe atherosclerosis and thickened arterial walls, and can also be used in spinal AMV procedures.