Optimal Timing and Dosage of ICG for Biliary Visualization During Cholecystectomy
Indocyanine green (ICG) should be administered intravenously at a dose of 0.1 mg approximately 30 minutes before laparoscopic cholecystectomy for optimal visualization of biliary structures. 1
Timing of ICG Administration
- ICG should be administered intravenously approximately 30 minutes before the surgical procedure begins to achieve optimal visualization of biliary structures 1
- This timing allows for adequate hepatic uptake and biliary excretion of ICG, maximizing the bile duct-to-liver ratio (BLR) of fluorescence intensity 1
- Administering ICG too early (several hours before surgery) may result in excessive background liver fluorescence, while administering it too late may not allow sufficient time for biliary excretion 2
Optimal Dosage
- A low dose of 0.1 mg ICG administered intravenously 30 minutes before surgery provides the highest bile duct-to-liver ratio (BLR) before surgical dissection of the cystohepatic triangle 1
- This dosage shows superior visualization of extrahepatic biliary structures compared to both lower (0.025 mg) and higher doses (0.25 mg, 2.5 mg) 1
- Weight-based dosing at 0.0119 mg/kg administered one hour before surgery is an alternative approach that provides excellent visualization of the extrahepatic biliary tree 3
- Traditional higher doses (2.5 mg) used in earlier studies result in excessive background liver fluorescence that can obscure biliary structures 2, 4
Alternative Administration Methods
- Direct intrabiliary injection of ICG (via percutaneous transhepatic gallbladder drainage, gallbladder puncture, or endoscopic nasobiliary drainage) at a dosage of 0.025 mg can be considered in specific cases 5
- Intrabiliary injection provides 100% visualization of biliary structures compared to 83.3% with intravenous injection, but requires additional invasive procedures 5
Clinical Benefits and Considerations
- ICG fluorescence cholangiography is a useful adjunct for confirming biliary anatomy during laparoscopic cholecystectomy without the need for X-ray imaging 6, 5
- The technique helps prevent bile duct injuries, which occur in 0.4% of elective and 0.8% of emergency laparoscopic cholecystectomies 6, 2
- ICG cholangiography is particularly valuable in cases with difficult anatomy, acute cholecystitis, or when intraoperative cholangiography (IOC) cannot be used 6
- While ICG cholangiography is promising, routine use to reduce bile duct injury rates is not yet recommended in guidelines (Grade 2C recommendation) 6
Pitfalls and Caveats
- Excessive ICG dosage leads to significant background liver fluorescence that can obscure biliary structures rather than enhance visualization 1, 4
- The optimal timing and dose may need adjustment in patients with impaired liver function, as ICG is primarily cleared by the liver 5
- ICG cholangiography should be considered as an adjunct to, not a replacement for, the critical view of safety technique during laparoscopic cholecystectomy 6
- ICG administration has a learning curve, and surgeons should be familiar with the technology and interpretation of fluorescent imaging 2