Is there still a role for functional radionuclide study of the liver?

Clinical applications of radionuclide methods for the study of liver hemodynamics and hepatocyte function are examined. In particular, as for hemodynamic studies, perfusion assessment with radiocolloids, 99mTc-IDA scintigraphy or 99mTc-labeled red blood cells, is underlined; they allow characterization of the different cellular component of space-occupying liver processes. The use of hepatic perfusion index (HPI) is reconsidered both as prognostic parameter in cirrhotic patients and as predictor of liver metastasis from colorectal cancer. The diagnostic role of recent procedures, as those based on endorectal radiopharmaceuticals in the evaluation of portosystemic shunts in cirrhosis, is analyzed. Studies of hepatocyte function of practical concern are essentially devoted to the "excretory function" and "asialoglycoprotein metabolism". In the first case, a major role is played by IDA halogenated derivatives and functional parameters drawn from them by mathematico-statistical evaluations of radiohepatogram (simple or applied to compartmental models). For metabolic studies, at present an artificial glycoprotein, 99mTc-galactosylneoglycoalbumin (99mTc-NGA) that binds with hepatocellular receptors is used. Information on the rate of blood plasma clearance and liver uptake, receptor density (altered in some pathologic conditions) and plasmic hepatic flow, is supplied.