Parenchymal phase refers to the staging of the liver on enhanced CT scan. When liver enhanced CT examination, liver parenchyma and intrahepatic blood vessels behave differently in different periods of enhanced scanning, which are divided into three phases, arterial phase, parenchymal phase and venous phase; the liver has the characteristics of common blood supply of portal vein and hepatic artery, and the difference of enhanced CT imaging in the three phases will help analyze the cause and the degree of development of the lesion. Enhanced CT scanning of the liver refers to the CT scanning performed after injection of contrast agent, which is divided into three phases, and these three phases can determine the blood flow characteristics of the patient’s lesion, so as to analyze and judge the nature of the lesion. In the arterial phase, the density of liver parenchyma is similar to that of CT plain scan; in the parenchymal phase, the liver parenchyma and portal vein are obviously strengthened, and the liver parenchyma is still obviously strengthened in the venous phase. For example, in patients with hepatocellular carcinoma, the enhancement is most obvious in the arterial phase and slightly weaker in the parenchymal phase; in patients with hepatic hemangioma, the enhancement is slightly stronger in the parenchymal phase and stronger in the venous phase. If you feel unwell, you should go to the hospital in time and consult your physician.