Coronary CTA is an important screening test for coronary artery disease. The main application of iodine contrast agents, such as iodixanol and other drugs, during the examination process, such drugs have the risk of causing allergic reactions and contrast nephropathy. During the examination, it is necessary to absorb radiation, and there is a certain amount of radiation damage to the patient, but this radiation dose is relatively safe. Patients should inform the doctor before the examination if they have a previous history of iodine allergy, such as allergy to seaweed, seafood and other foods. Be careful if there is a history of such allergies, as there is a risk of allergic reactions. Some patients have severe deterioration of kidney function. Such patients should not undergo such tests, which may lead to severe deterioration of kidney function and even the need for dialysis.