Paradoxical alteration of indocyanine green concentration in bile and the visibility of the intra-operative fluorescence cholangiography in pigs

Abstract Background: A significant difference exists between the reported optimal timing of indocyanine green (ICG) injection during fluorescence cholangiography and ICG dissipation time from the serum. There are no reports on alterations in ICG concentration in biliary fluid over time. Herein, we measured the concentration of ICG and the fluorescence intensity ratio between the common bile duct (CBD) and liver, which was recognized as a parameter of the visibility of the CBD. Materials and methods: ICG (0.05 mg/kg) was injected