Low-density nodules are generally described by CT images, and according to different parts, low-density nodules may be different lesions or diseases, for example, low-density nodules in liver area may be liver cysts, liver cancer, etc.; low-density nodules in kidney area may be renal cysts, renal cancer, etc.; low-density nodules in pancreas area may be pancreatic cysts, pancreatic cancer, etc. 1. Liver hypodense nodules: liver cysts usually have lower density than surrounding tissues and appear as hypodense nodules under CT; in addition, some necrotic liver cancers may also appear as hypodense nodules. 2. Renal hypodense nodules: renal cysts also show hypodense nodules under CT because their density is lower than that of surrounding tissues, and secondly, some renal cancers can also show hypodense nodules under CT, which need further enhancement examination to identify. 3. Pancreatic hypodense nodules: pancreatic cysts are also hypodense nodules under CT, and some pancreatic cancers can also be hypodense nodules due to less blood supply and necrosis. Low-density nodules may be different kinds of lesions or diseases, and it is suggested that patients should judge according to the specific situation or further examination under the guidance of doctors.