Polyps are commonly found in gallbladder polyps, gastric polyps, and intestinal polyps, and some polyps are visible in CT examinations and some are not. The size of polyps, long parts, the relationship between polyps and adjacent groups of tissues, for example, clinically gallbladder polyps are found under ultrasound 2mm, 3mm, 4mm polyps, but can not be seen by doing CT, then patients are confused, how CT such a high-end examination can not find polyps, in fact, its imaging is not the same way. When doing abdominal CT, more parenchymal organs are seen, for polyps, which are particularly small, the demarcation between the polyp and the surrounding structures is not clear and cannot be seen under CT. Therefore, we often encounter polyps that are visible on ultrasound but not on CT. For gastric polyps and intestinal polyps, you need to pay attention to the examination method. It is also more difficult to see the polyps if the stomach and intestine are in the empty state. There are also intestinal contents in the intestine, i.e. fecal matter has an effect on polyps.