Spinal canal imaging, also known as myelography, involves injecting a contrast agent into the subarachnoid space of the spinal cord after a lumbar puncture or a puncture of the medullary pool of the cerebellum, and observing the flow and morphology of the spinal canal under fluoroscopy by changing the patient’s position. It is commonly used to diagnose intraspinal lesions or the presence or absence of blockage in the spinal canal. Commonly used contrast agents are iodobenzol, and gas may also be used. It is often used for intravertebral tumors, arachnoid adhesions, and spinal cord compression where the location and nature of the lesion must be determined. In some patients with complex conditions, the diagnosis and localization cannot be clarified after X-ray or CT examinations, or if there is a suspicion that there may be lesions in other areas, a spinal canal angiography can be considered. In patients with metal in the body, vertebral canal imaging may also be considered when MRI is not possible. Vertebral canal imaging involves injecting contrast into the subarachnoid space and then judging the entire canal based on the flow of the contrast in the canal for clear diagnosis and localization. Since the contrast agent used in the past was iodine oil or iodophenyl ester, etc., which is absorbed very slowly, some patients had cauda equina irritation. At present, most hospitals use water solvent, which is absorbed quickly and patients basically have no adverse reactions. However, since the contrast agent is absorbed quickly, the photography needs to be timely, otherwise it will not be clearly visualized after absorption and then photography.