If the disease cannot be determined by other means of examination, such as ultrasound, CT, blood tests, etc., imaging can be used to help clarify the diagnosis. Clinically, imaging is usually needed when there is a need to clarify the presence of lesions in tissues and organs such as cardiovascular, cerebrovascular, urinary system diseases, digestive system, etc. 1. cardiovascular system: coronary angiography is needed for patients who need to identify chest pain and angina, observe the presence of coronary artery abnormalities, as well as some pre-operative examination and post-operative review of heart disease; 2. urinary system: for example, to examine the urinary system such as kidney, bladder, ureter, etc. The upper gastrointestinal tract angiography is needed to examine the stomach, duodenum, oropharynx and esophagus for lesions; hepatic angiography is needed to examine the blood vessels of the liver for deformities, blockages, distribution patterns and tumors in the liver; and to observe the course of the biliary tract to determine the presence of bile duct Cholangiography is needed to observe the course of the bile duct and determine whether there is bile duct occlusion, bile duct stenosis, bile duct tumor, gallstones, etc.; 4. Respiratory system: bronchial stenosis, tracheal displacement, bronchial dilatation, etc. wheezing and arteriography abnormalities can be done; 5. Reproductive system: tubal angiography is needed to check whether the fallopian tubes are blocked; 6. Cerebrovascular system: ventriculography is needed to analyze the shape, location and size of the ventricles and to diagnose intracranial tumors. Ventriculography.