How the ICG behaves with timing in laparoscopic cholecystectomy
| Discussion in 'All Categories' started by Dr. Kalpana Srivastava - Dec 16th, 2025 8:06 am. | |
Dr. Kalpana Srivastava
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Hi I want to know ehen i inject IV 45 minute before the laparoscopic cholecystectomy How the ICG behaves with timing in laparoscopic cholecystectomy. what are the best timing. |
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re: How the ICG behaves with timing in laparoscopic cholecystectomy
by Dr. Anup -
Dec 16th, 2025
8:09 am
#1
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Dr. Anup
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How ICG behaves when injected 45 minutes before laparoscopic cholecystectomy After IV injection of ICG • ICG binds rapidly to plasma proteins (mainly albumin) • It is extracted exclusively by hepatocytes • It is excreted unchanged into bile • There is no enterohepatic circulation So the fluorescence you see during cholecystectomy depends entirely on timing. ⸻ Timeline of ICG behavior (Clinically important) 0–2 minutes • ICG seen in hepatic arteries and portal veins • Liver parenchyma lights up strongly • Not useful for biliary anatomy 5–10 minutes • Strong hepatic parenchymal fluorescence • Minimal biliary visualization • Cystic duct usually not visible clearly 20–30 minutes • ICG starts appearing in intrahepatic bile ducts • CBD begins to fluoresce faintly • Background liver still bright → contrast is suboptimal 45–60 minutes ✅ • Excellent biliary excretion • CBD and CHD clearly fluorescent • Liver background fluorescence starts fading • Best window if injected intra-operatively 2–6 hours ⭐ (Best contrast) • Liver background almost gone • Bile ducts remain fluorescent • Maximum duct-to-liver contrast • Ideal for difficult Calot’s triangle 12–24 hours • Very strong biliary fluorescence • Practically no liver background • Excellent for elective, planned cases ⸻ So what happens if you inject 45 minutes before surgery? ✔ You will see: • CBD and CHD clearly • Cystic duct usually visible • Some residual liver fluorescence (acceptable) ⚠ Limitations: • In obese patients or acute cholecystitis → contrast may be reduced • Inflamed cystic duct may not fluoresce well But for routine LC, this timing is clinically safe and effective. ⸻ Best timing options (Practical recommendation) Routine laparoscopic cholecystectomy • 0.25 mg/kg IV • Inject 45–60 minutes before skin incision ✔ Most commonly used in OT ✔ No delay in surgery ⸻ Difficult / anticipated difficult cholecystectomy (Mirizzi, acute inflammation, frozen Calot’s) • Inject 2–6 hours before surgery ✔ Best duct–liver contrast ✔ Safest identification ⸻ Elective planned cases • Inject Evening before surgery (12–18 hours) ✔ Gold-standard visualization ✔ Minimal background fluorescence ⸻ Why surgeons get confused about timing Many believe: “Earlier injection = better imaging” That is partly true, but the key concept is: We want bile ducts fluorescent, not liver parenchyma Hence delayed imaging is superior. ⸻ Dose clarification (important) • Standard dose: 0.25 mg/kg IV • Do not exceed 5 mg total in one injection • Dilute in 10 mL sterile water • Inject slowly over 30–60 seconds |