How low can you go? Intraoperative microdosing of indocyanine green for fluorescence cholangiography during laparoscopic cholecystectomy.
Ryan C Broderick, Graham J Spurzem, Ana Garcia Cabrera, Patricia Ruiz-Cota, Amanda Rocha, Edgardo Reyes, Agustina Altolaguirre, Andres Fontaine-Nicola, Hannah M Hollandsworth, Bryan J Sandler, Santiago Horgan, Garth R Jacobsen
Surgical endoscopy October 1, 2025 DOI: 10.1007/s00464-025-12057-w (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Retrospective review of a prospectively maintained database Peer reviewed |
|---|---|
| Sample size | 100 |
| Population | Patients who underwent laparoscopic cholecystectomy at the authors' institution from 2021 to 2024 |
| Interventions | Indocyanine green (ICG) Microdose protocol |
| Dose | 0.5 mg (microdose); 7.5 mg (standard) |
| Measures | 4-point Likert scale for signal strength, clarity, and usefulness |
| Topics | Microdosing |
| Keywords | Fluorescence cholangiography Indocyanine green Laparoscopic cholecystectomy Microdose Minimally invasive surgery |
| Key findings | Intraoperative microdose ICG (0.5 mg) provides biliary visualization during laparoscopic cholecystectomy that is non-inferior to a standard preoperative dose of 7.5 mg. |
Abstract
Fluorescence cholangiography (FC) with indocyanine green (ICG) enables real-time intraoperative visualization of extrahepatic biliary anatomy during laparoscopic cholecystectomy (LC). There is no consensus on the optimal ICG dose or timing of administration for LC. The goal of this study was to implement a simple intraoperative low-dose ("microdose") ICG protocol that facilitates non-inferior biliary visualization compared to a standard dose protocol to streamline perioperative workflows. A retrospective review of a prospectively maintained database identified patients who underwent LC at our institution from 2021 to 2024. Microdose protocol patients were intravenously administered 0.5 mg ICG upon induction of general anesthesia, while standard protocol patients received 7.5 mg ICG 60-120 min preoperatively. Operative video from cases in both groups were reviewed to compare the frequency of cystic duct (CD), common bile duct (CBD), and common hepatic duct (CHD) visualization with FC. A 4-point Likert scale survey was completed for each case to compare ICG signal strength (1 = no signal; 4 = very strong), clarity from background interference (1 = cannot discern signal from background; 4 = no interference), and usefulness in clinical decision-making (1 = no benefit; 4 = essential). A total of 100 patients were identified (N = 50 microdose; N = 50 standard). For microdose cases, the mean time from ICG administration to skin incision was 16.7 ± 5.6 min, and mean operative time was 47.4 ± 20.2 min. Compared to 50 standard dose cases, CD visualization before hepatocystic triangle dissection with the microdose protocol was 86.0% vs 88.0% (p = 0.99). The CBD and CHD were seen in all cases for both groups. There were no significant differences in average score for signal strength (3.6 ± 0.5 vs 3.7 ± 0.5, p = 0.32), signal clarity (3.4 ± 0.5 vs 3.3 ± 0.5, p = 0.32), or usefulness in clinical decision-making (4.0 ± 0.0 vs 4.0 ± 0.0, p = 0.99) between groups. Microdose ICG can be given intraoperatively to provide excellent biliary visualization during laparoscopic cholecystectomy, eliminating the historical workflow of preoperative ICG administration.
Comparable studies
Other observational and cohort studies on microdosing, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Microdosing psychedelics: personality, mental health, and creativity differences in microdosers Respondents recruited from online forums | 2019 | Observational study | |
| Positive expectations predict improved mental-health outcomes linked to psychedelic microdosing Individuals planning a weekly microdosing regimen | 2021 | Prospective observational study | n = 81 |
| Might Microdosing Psychedelics Be Safe and Beneficial? An Initial Exploration. More than a thousand individuals from 59 countries | 2019 | Observational cohort | n = 1,000 |
| Psilocybin microdosers demonstrate greater observed improvements in mood and mental health at one month relative to non-microdosing controls Psilocybin microdosers and non-microdosing comparators | 2022 | Naturalistic observational study | n = 1,133 |
| Nonlinear Pharmacokinetics of Oral Quinidine and Verapamil in Healthy Subjects: A Clinical Microdosing Study Healthy subjects | 2011 | Observational cohort |