Whether or not to do CT examination after duodenal endoscopy needs to be judged according to the purpose of the examination, the disease suffered, and so on. If it is just a simple physical examination and no specific lesions are found after duodenal endoscopy, CT examination can be dispensed with. If polyps or other occupying lesions are found, biopsies should be taken for pathologic examination, and CT should be done to further define the extent of the lesions if they are malignant. If there are existing upper gastrointestinal symptoms, such as acid reflux, heartburn, nausea, vomiting, vomiting blood, abdominal distension, etc., and patients suspected of esophageal, gastric, duodenal lesions, they need to be further examined in order to make a definitive diagnosis, and after duodenal endoscopy, they can do CT examination of the upper abdomen, which can combine with the imaging to clarify the nature of the lesion. Patients should be examined under the guidance of a physician.