To address this concern, we need to briefly understand the characteristics of the blood supply to the liver. The blood vessels of the liver include two groups: the vessels entering the liver and the vessels leaving the liver. The vessels entering the liver are also called the portal vascular system, including the intrinsic hepatic artery and portal vein; the vessels exiting the liver are the hepatic venous system. The portal vein is the functional vessel of the liver, accounting for 3/4 of the liver blood supply, while the hepatic artery is the nutrient vessel of the liver, accounting for 1/4 of the liver blood supply, with a pressure 30-40 times higher than that of the portal vein, which is more important than the hepatic artery in maintaining the function of the liver. In the case of hepatocellular carcinoma, for example, contrast-enhanced dynamic CT and MRI scans are particularly important for the diagnosis of hepatocellular carcinoma. The typical presentation of hepatocellular carcinoma is significant enhancement in the arterial phase of the enhanced scan, which is less enhanced than the surrounding liver tissue in the venous phase and continues to fade with contrast in the delayed phase, which is a highly specific imaging presentation of hepatocellular carcinoma. The exact diagnosis of hepatocellular carcinoma requires four stages: plain, arterial, venous, and delayed stages, the latter three of which are dependent on enhancement scans. Therefore, to better define the benignity and malignancy of the liver-occupying lesions (masses in the liver), patients are still recommended to undergo enhanced CT and MRI examinations.