Lung CT will usually scan part of the liver, and if the scanned liver has lesions, it will be reflected in the report. Low-density shadow in the liver usually suggests benign or malignant space-occupying lesions in the scanned liver. 1. Benign space-occupying lesions: These usually include liver cysts, heterogeneous fatty liver, liver abscess, liver hemangioma, liver adenoma and so on. Except for liver abscess, the disease is relatively mild and needs to be further differentiated from malignant lesions. 2. Malignant space-occupying lesions: mainly hepatocellular carcinoma. Usually, patients are recommended to improve the examination of liver enhanced CT, liver MRI, liver function, serum AFP and so on to identify benign and malignant lesions. If physical examination reveals low-density shadow in the liver, patients should go to gastroenterology department or general surgery department of regular hospitals for further examination to make clear diagnosis and treatment.