Rounded low-density shadow in the liver indicates the presence of occupying lesions in the liver, such as hepatic hemangioma, hepatic cyst, hepatic abscess or hepatic cystadenoma. 1. Hepatic hemangioma: Hepatic hemangioma can be caused by congenital factors, endocrine or intrahepatic capillary congestion, dilatation and other factors, liver ultrasound can be seen in the liver with localized type of enlargement, internal hypoechoic tumors, which may be accompanied by intra-tumor blood flow and hepatic blood flow communication. 2. Liver cysts: Liver cysts can be caused by inflammation, trauma or parasitic infection and other factors resulting in cystic changes of the liver, such as solitary liver cysts or multiple liver cysts. Liver ultrasound can show cystic, low density, round-like signs in the lesion. 3. Liver abscess: when liver infection occurs, the lesion may be limited to a round-like hypodense shadow, which is mainly caused by liquefaction of the infected lesion, such as bacterial or amoebic liver abscess. 4. Hepatic cystadenoma: there may be mucus secreted by glands inside the hepatic cystadenoma, so a single, rounded liquid dark area can be detected in liver ultrasound, and intervals can be seen inside the tumor to separate it into multiple cystic cavities. In addition, primary hepatocellular carcinoma and secondary hepatocellular carcinoma may also manifest as round-like hypodense shadows. Therefore, when finding round-like hypodense shadows in the liver, one should consult the doctor in time to clarify the condition and receive appropriate treatment.