Quantitative temporal analysis of 99mTechnetium p-isopropyl-iminodiacetic acid (PIPIDA) as a measure of hepatic function in health and disease. 
Excretory liver function was analyzed in 10 healthy volunteers and 28 subjects with acute or chronic liver injury following intravenous administration of 99mtechnetium p-isopropyl iminodiacetic acid.  Hepatobiliary transit of this agent was quantitated at 5-min intervals for a total of 60 min.  Indices of total liver activity, liver cell uptake, liver parenchymal clearance, and bile duct clearance of 99mtechnetium p-isopropyl iminodiacetic acid were calculated from time--activity curves over heart, liver, extrahepatic bile ducts, and gallbladder.  Seven subjects with acute viral hepatitis, 15 with extrahepatic biliary obstruction, and 6 with intrahepatic cholestasis were evaluated.  Compared with healthy volunteers, a significant (p less than 0.0001) reduction in total liver activity and liver parenchymal clearance was demonstrated in all patient groups.  Major resolution in all liver-derived indices, particularly total liver activity, occurred during convalescence from hepatitis and after biliary drainage.  Nonmeasurable bile duct clearance always indicated a diagnosis of extrahepatic obstruction in cholestatic subjects, and this index normalized in subjects following biliary drainage.  Whereas visual assessment of 99mtechnetium p-isopropyl iminodiacetic acid scans provided limited, useful information about the functional status of the liver, quantitative temporal analysis proved to be a much more effective technique.