The investigators included patients undergoing laparoscopic cholecystectomy by a single surgeon between September and December 2013 at a single centre university department with unrestricted referral of patients. The included patients represented all patients undergoing laparoscopic cholecystectomy by one surgeon during the study period. All patients underwent intra-operative fluorescent cholangiography (IFC) with concomitant angiography, according to a standardized protocol, during their laparoscopic cholecystectomy.

A standardized protocol with IFC including concomitant angiography was performed during laparoscopic cholecystectomy.

Intra-operative fluorescent-imaging-mode-time was registered by a study-nurse during the operations (performed between september and december 2013)

The operating surgeon completed a structured questionnaire immediately after each operation regarding anatomical identification by IFC (visible cystic duct, -common bile duct, -common hepatic duct, -right and left hepatic ducts, -cystic artery, -aberrant bile ducts, and/or other abnormalities).

Successful IFC was defined as exposure of the junction between the cystic duct, common bile duct and common hepatic duct by IFC. Success-full fluorescent angiography was defined as adequate visualisation of the cystic artery within Calot´s triangle by the method.