A comparison of three indices of relative hepatic perfusion derived from dynamic liver scintigraphy

Data from dynamic radiocolloid liver scintigraphy (DLS) have been analysed to calculate three indices of relative arterial to total hepatic perfusion. Ninety subjects have been studied, comprising 21 normals, 62 patients with metastatic liver disease and 7 patients with cirrhosis. Correlation coefficients above 0.81 were found in all patient groups between an index based on rates of liver uptake (the hepatic perfusion index, HPI) and a method based on quantitative liver uptake (the mesenteric fraction, MF). A further method employing the spleen to model arterial inflow (hepatic arterial ratio, HAR) had less agreement with both HPI and MF, with correlation coefficients below 0.76. Posterior images have previously been used to calculate HAR, and greater errors are expected in HAR from the anterior images acquired in this study. Receiver operating characteristic analysis showed that the diagnostic performance of HPI and MF indices in metastatic disease were not significantly different. For anterior image data analysis both HPI and MF were superior to HAR.