A model of the hepatic perfusion index in the rat.

The hepatic perfusion index (HPI) is an indicator of the relative hepatic arterial to total liver blood flow as measured by dynamic flow scintigraphy. Hitherto, accurate assessment of the HPI in small animals has not been possible because of methodological difficulties. A reproducible method for measuring the HPI by dynamic scintigraphy in rats is described using a rapid intraventricular bolus administration of 0.04 ml 99Tcm sulphur colloid. There was no significant difference between the HPI determined by dynamic scintigraphy and and that calculated from absolute measurements of hepatic arterial and total liver blood flow. These results indicate that the HPI derived by dynamic scintigraphy in the rat is a true estimate of the ratio of the hepatic arterial to total liver blood flow.