Whether a 0.9 cm nodule on the liver is important or not depends mainly on the nature of the nodule, liver nodules are mainly divided into benign nodules and malignant nodules. 1. Benign nodules: if the patient does not have underlying liver diseases, such as viral hepatitis, alcoholic liver, etc., most of the liver nodules are benign nodules, such as hemangiomas, hepatic cysts, hepatic adenomas, etc., hemangiomas and hepatic cysts seldom undergo malignant changes, and need to be closely followed up for observation of changes in size. In combination with hepatitis, there may be cirrhotic nodules, which are also benign nodules. 2. Malignant nodules: if the patient has underlying liver diseases such as hepatitis B and cirrhosis, the possibility of malignant nodules should be highly suspected. Malignant nodules mainly include primary hepatocellular carcinoma, intrahepatic cholangiocarcinoma and intrahepatic metastatic carcinoma, etc. The growth rate of malignant nodules is often relatively fast, which requires early and active intervention. In case of abnormal liver imaging results, it is recommended to consult a doctor in a timely manner to clarify the cause of the disease with the help of a doctor and carry out targeted treatment or therapy.