CT is a means of imaging examination, which is mainly sensitive to substantial organs. And the location of upper abdomen mainly includes liver, gallbladder, pancreas, spleen and part of small intestine and colon, so doing CT of upper abdomen can find out whether there are substantial organ lesions in the corresponding parts, such as liver, pancreas, spleen, gallbladder, etc. In addition, it can also check some lesions of cavity organs, such as stomach and intestines, etc. 1. Liver: for example, if the patient has lesions in the liver, hypodense foci in the liver, or the presence of liver cysts, liver hemangioma If the patient has lesions in the pancreas and spleen, such as pancreatic tumor, spleen cyst, etc., the initial diagnosis can also be confirmed by CT examination of the upper abdomen; 3. obstruction, etc., can also be initially determined by CT examination of the epigastrium, which can reveal high-density lesions inside the gallbladder or common bile duct; 4. Gastrointestinal: CT examination can initially determine whether there are lesions inside the patient’s stomach or duodenum, and part of the colon, but the sensitivity is relatively low. Some smaller lesions, such as polyp-like lesions, may not be detected by CT examination. However, for larger masses, such as relatively large gastric or colon cancers and mesenchymal tumors, they can be detected by CT examination of the epigastrium, and gastroscopy or colonoscopy is needed for further confirmation of the diagnosis.