Comparison of 99mTc-HEPIDA and 99mTc-MBrIDA from the standpoint of hepatic clearance determination - preliminary communication

BACKGROUND. In order to evaluate the functional capacity of the liver by means of clearance determination, the derivative of iminodiacetic acid (99mTc-HEPIDA) has been used in recent decades. Because of recent problems with manufacturing and delivery of 99mTc-HEPIDA, an investigation was undertaken with the aim of testing whether a more widely available 99mTc-MBrIDA could be used for clearance determination and whether hepatic clearance measured with the use of this compound provides a similarly useful test of hepatic function. MATERIAL AND METHODS. Comparative investigations were performed in 73 patients of both sexes. The state of the efficiency of liver parenchyma was determined based on seven widely used biochemical tests, i.e. levels of: bilirubin, albumin, and gamma globulin; activity of AST, ALT, GGTP, and prothrombin index. The clearances of both radiopharmaceuticals, 99mTc-HEPIDA and 99mTc-MBrIDA, were determined by means of multisample technique. The results of determination were correlated among themselves and with the results of biochemical tests. The set of results of all estimations allowed a factorial analysis to be performed to find a common factor and to compute the values of factor loadings in particular tests. RESULTS. Obvious correlation between plasma and hepatic clearances of both radiopharmaceuticals was obtained and between plasma clearance of 99mTc-MBrIDA and hepatic clearance of 99mTc-HEPIDA. Correlation coefficients of 99mTc-MBrIDA clearance and the biochemical test results attained somewhat lower values than for 99mTc-HEPIDA clearance. Similarly, values of χ2 test of independence of 99mTc-MBrIDA clearances and test results were also less close than for 99mTc-HEPIDA clearances. Factorial analysis showed that common factor loading is greatest for hepatic clearance of 99mTc-HEPIDA; the values of two loadings of 99mTc-MBrIDA clearances are very close, but somewhat lower than those for 99mTc-HEPIDA. CONCLUSIONS. From the performed investigations it is possible to conclude that 99mTc-MBrIDA clearances may be used for the evaluation of liver parenchyma performance, even if the results may not be as certain as those obtained using 99mTc-HEPIDA