Intraoperative biliary anatomy visualization using indocyanine green fluorescence micro-dosing: a quantitative...

Area of Science:

• Surgical innovation
• Medical imaging
• Pharmacokinetics

Background:

• Laparoscopic cholecystectomy safety is paramount, with bile duct injury a key concern.
• Near-infrared (NIR) fluorescence cholangiography using indocyanine green (ICG) aids biliary anatomy visualization.
• Optimal ICG dosing for enhanced contrast without increased liver fluorescence remains undetermined.

Purpose of the Study:

• To quantitatively assess weight-adjusted systemic ICG regimens.
• To evaluate the impact of ICG dose on bile duct-to-liver fluorescence contrast.
• To determine the temporal stability of contrast within an operative window.

Main Methods:

• Ten pigs received intravenous ICG at five weight-adjusted doses (0.000625–0.05 mg/kg).
• NIR fluorescence imaging was performed at 30, 60, and 90 minutes post-injection.
• Bile duct and liver regions were segmented for pixel-wise intensity extraction and contrast ratio calculation.

Main Results:

• ICG fluorescence was detectable across all doses and time points (30–90 min).
• Micro-dose ICG (≤0.01 mg/kg) yielded significantly higher bile duct-to-liver contrast ratios compared to higher doses (p=0.034).
• No significant effect of time on contrast was observed within the evaluated window.

Conclusions:

• Systemic weight-adjusted micro-dose ICG enhances bile duct visualization in a preclinical model.
• These findings support further research into standardized micro-dose protocols for fluorescence-guided surgery.
• Quantitative fluorescence imaging may improve intraoperative safety during laparoscopic procedures.