Changes in the hepatic perfusion index during the growth and development of experimental hepatic micrometastases.

: Micrometastases were induced in Fisher rats using an intraportal inoculation of 0.2 ml of 8 x 10(7) Walker carcinosarcoma cells. A control group received normal saline. The hepatic perfusion index (HPI) was measured during the growth and development of micrometastases. The HPI at 4 days (0.51 +/- 0.008) and at 6 days (0.65 +/- 0.16) was significantly raised when compared to controls (0.31 +/- 0.07) and at 2 days after inoculation (0.31 +/- 0.06). Hepatic artery flow did not change throughout the study period. However, portal venous inflow was decreased significantly at 4 and 6 days (0.57 +/- 0.16 and 0.55 +/- 0.11) when compared to controls (0.96 +/- 0.34). These results indicate that the change in the hepatic perfusion index is related to a decrease in portal venous inflow. The decrease in portal venous inflow could be a mechanical effect of the micrometastases on intrahepatic blood flow or to increased arteriovenous shunting.