Validation set analysis to predict postoperative outcomes by technetium-99m galactosyl serum albumin scintigraphy for hepatectomy.

Background The indocyanine green retention rate at 15 min (ICGR15) is a gold standard parameter of liver function when deciding on the extent of hepatectomy. However, ICGR15 is influenced by several hepatic conditions. To evaluate auxiliary preoperative liver functional reserve, we examined the clinical significance of modified parameters by blood tests and technetium-99m galactosyl human serum albumin (Tc-99m-GSA) scintigraphy. Methods We measured liver function parameters, including the hepatic uptake ratio (LHL15) and the blood pool clearance index (HH15) of Tc-99m-GSA and their modified formulae [LHL/HH15, LHL minus HH15, and converted ICGR15 (cICGR15) from a preliminary study] in 229 patients, including 18 with biliary obstruction. Results The mean values of LHL15/HH15, LHL minus HH15, and cICGR15 were 1.646 +/- 0.295, 0.347 +/- 0.116, and 13.2 +/- 5.3%, respectively. These parameters correlated significantly with other liver functions measured by blood tests except for the bilirubin level (P < 0.05) although the actual ICGR15 level correlated positively with the bilirubin level. The difference of ICGR15 (ICGR15 minus cICGR15) in patients with biliary obstruction tended to be higher in comparison with that in patients without biliary obstruction (P = 0.044). Values of LHL/HH15, LHL minus HH15, and the cICGR15 were not significantly associated with postoperative complications. Conclusion The modified parameters of Tc-99m-GSA were useful for evaluating hepatic function in patients with high bilirubinemia due to biliary obstruction. However, it remains difficult to establish a more reliable parameter as a standard hepatic function test instead of ICGR15.