Cardiovascular imaging is a technique to diagnose diseases of the heart and large blood vessels by rapidly injecting iodine contrast into a vein or artery or directly into the heart and aorta through a catheter to visualize the heart and aorta, and then photographing the entire visualization of the heart and large blood vessels for analysis by speed photography. By observing the filling of the heart chambers and great vessels and the sequence of their visualization, we can understand the anatomical situation such as the shape, size, location, and interconnections of the great vessels in the heart chambers. For example, the doctor can clarify the size of the large vessels, the presence of structural malformations of the heart and the size of the vessels within the heart, the presence of structural malformations of the heart and blood shunts within the heart, and also find out the size, shape and location of the thrombus present through cardiovascular angiography. It is a “golden indicator” for the diagnosis of congenital malformations of the heart and certain large vessel diseases. Indications and contraindications for cardiac angiography: The indications include certain congenital cardiovascular malformations and acquired cardiovascular diseases. Contraindications are: 1. Allergy to iodine and other allergic diseases. 2. 2. Severe liver disease and kidney disease. 3. Severe cardiomyopathy and coronary circulation disorders, such as coronary artery disease. 4.Severe hypoxia and heart failure. The main methods of cardiac angiography: 1, intravenous method: subcutaneous puncture through the vein to inject contrast, the method is based on the physiological circulation for imaging. This method is based on the physiological circulation. Because the contrast is not satisfactory enough, there are still some limitations to the diagnosis. 2, intubation method: mainly includes intravenous intubation method and arterial intubation method. Venous cannulation method is a method to selectively place the catheter into the specific lumen of the large blood vessels of the heart through the vein and inject the contrast agent to make it visualize, and this method has been widely used in the diagnosis of right heart, pulmonary artery and right-to-left shunt diseases; arterial cannulation method refers to placing the catheter in the aorta or left atrioventricular cavity through the artery and injecting the contrast agent to make it visualize, and this method has been widely used in the diagnosis of aorta, left ventricle and left-to-right shunt diseases. This method has been widely used for the diagnosis of aortic, left ventricular and left-to-right shunt diseases.