Inadequacy of the 133Xe intrahepatic injection technique for the assessment of hepatic blood flow in man.

Local hepatic blood flow was measured by use of the 133Xe clearance technique following the direct injection of the tracer into the right lobe of the liver in twenty-two patients without liver disease. The clearance of the radioactive gas from the organ was monitored by means of a gamma-camera. The analysis of the wash-out curves, in order to measure hepatic blood flow, was performed by two methods based on a monocompartmental and bicompartmental model, respectively. A large variability of the results was observed, possibly explained by inhomogeneous perfusion and inhomogeneity of the liver parenchyma. The complexity of the Xenon kinetics in the liver requires at least a bicompartimental model for the analysis of the clearance curves. The method is of limited usefulness in the assessment of liver function activity.