To estimate vascular changes in chronic liver disease, we quantitated intrahepatic arteriovenous and portal-systemic shunts in 12 patients with cirrhosis and arteriovenous shunts alone in 4 patients with cirrhosis. An index was obtained for intrahepatic arteriovenous shunts by instilling technetium 99m-macroaggregated albumin into the proper hepatic artery and portal-systemic shunts, by the same procedure done in the portal trunk, near the porta hepatis on different days. Counts were taken over the liver and both lungs in the anterior as well as the posterior view for calculation of the shunt index: cpm in lungs divided by cpm in liver and lungs X 100%. In the 12 patients with cirrhosis in whom both shunts were measured, intrahepatic arteriovenous shunting was significantly lower compared with intrahepatic portal-systemic shunting (1.4% +/- 1.1% vs. 36.0% +/- 29.0%, p less than 0.001). Thus, it seems that in patients with cirrhosis, the development of intrahepatic arteriovenous shunts is not as great as that of portal-systemic shunts, which were found in this study to be considerable and variable in degree.