Prediction of Indocyanine Green Retention Rate at 15 Minutes by Correlated Liver Function Parameters before Hepatectomy

BackgroundIndocyanine green retention rate at 15 min (ICGR15) is a useful marker of liver function in deciding on the extent of hepatectomy. To determine ICGR15 regardless of liver condition, we sought to establish a formula for converted ICGR15 based on conventional blood tests and technetium-99 m galactosyl human serum albumin (99mTc-GSA) scintigraphy.Materials and MethodsWe measured liver function parameters, including ICGR15, in 307 patients, including 265 liver cancer patients without biliary obstruction (no obstruction group) and 42 with biliary obstruction (obstruction group).ResultsIn the no obstruction group, multiple regression analysis identified blood pool clearance ratio (HH15), liver uptake ratio (LHL15) calculated by heart and liver activity between 3 and 15 min after injection of 99mTc-GSA, and serum hyaluronic acid as significant correlates (P < 0.05). The calculated converted ICGR15 was then equal to 0.02∗HA + 0.276∗(HH15∗100)–0.501∗(LHL15∗100) + 41.41. The mean difference between actual and converted ICGR15 was significantly lower in the obstruction than in the no obstruction group (P = 0.031). A significantly larger proportion of patients of the obstruction group had lower converted ICGR15 than those of the no obstruction group (P = 0.045).ConclusionThe converted ICGR15 is useful for evaluating hepatic function in patients with biliary obstruction who plan to undergo major hepatectomy.