Near-infrared Fluorescence Cholangiography Research Articles

Role of Intraoperative Near-Infrared Indocyanine Green Fluorescence Cholangiography in the Management of Acute Gangrenous Cholecystitis Secondary to Empyema of the Gallbladder in Mirizzi's Syndrome

Role of Intraoperative Near-Infrared Indocyanine Green Fluorescence Cholangiography in the Management of Acute Gangrenous Cholecystitis Secondary to Empyema of the Gallbladder in Mirizzi's Syndrome

Efficacy of different indocyanine green doses in fluorescent laparoscopic cholecystectomy: A prospective, randomized, double-blind trial.

Intraoperative bile duct injury is a significant complication in laparoscopic cholecystectomy (LC). Near-infrared fluorescence cholangiography (NIFC) can reduce this complication. Therefore, determining the optimal indocyanine green (ICG) dosage for effective NIFC is crucial. This study aimed to determine the optimal ICG dosage for NIFC. This was a prospective, randomized, double-blind clinical trial at a single tertiary referral center, including 195 patients randomly assigned to three groups: lower dose (0.01 mg/BMI) ICG (n = 63), medium dose (0.02 mg/BMI) ICG (n = 68), and higher dose (0.04 mg/BMI) ICG (n = 64). Surgeon satisfaction and detection rates for seven biliary structures were compared among the three dose groups. Demographic parameters did not significantly differ among the groups. The medium dose (72.1%) and higher dose ICG groups (70.3%) exhibited superior visualization of the common hepatic duct compared to the lower dose group (41.3%) (p < 0.001). No differences existed between the medium and higher dose groups. Similar trends were observed for the common bile duct and cystic common bile duct junction. In patients undergoing fluorescent laparoscopic cholecystectomy, the 0.02 mg/BMI dose of indocyanine green demonstrated better biliary structure detection rates than the 0.01 mg/BMI dose and was non-inferior to the 0.04 mg/BMI dose.

Efficacy of near-infrared fluorescence cholangiography using indocyanine green in 21 laparoscopic cholecystectomy: A retrospective study.

Efficacy of near-infrared fluorescence cholangiography using indocyanine green in 21 laparoscopic cholecystectomy: A retrospective study.

Fluorescence cholangiography for laparoscopic cholecystectomy: how, when, and why? A single-center preliminary study

Introduction Bile duct injuries avoidance is a key goal of biliary surgery. In this prospective study we evaluate the safety and feasibility of ICG fluorescent cholangiography during laparoscopic cholecystectomy (LC) focusing on the optimization of timing and dose administration. Material and methods From February to December 2022 fifty-four LC were performed with fluorescence imaging in our surgical department. 2.5 mg ICG were administered intravenously between 5 h and 24 h before surgery. Near-infrared fluorescent cholangiography (NIRF-C) was performed. Adequate fluorescence was evaluated by comparing agent accumulation in the gallbladder and the extrahepatic duct and the background of liver parenchyma. Results Biliary anatomy was identified in all cases. Median time of ICG administration was 11 h previous surgery and three groups of patients were identified: group A receiving ICG 5–9 h, group B 10–14 h, group C 15–24 h before surgery. Peak contrast was gained in group B, with minimal fluorescence of liver parenchyma and more intense visibility of the biliary tract. Intraoperative cholangiogram was unnecessary in all cases. Conclusion Fluorescent cholangiography during LC is safe and feasible overcoming the limits of other techniques available. 2.5 mg ICG administered 10–14 h before surgery produces optimal outcomes for near-infrared (NIR) fluorescent cholangiography.

Near-infrared indocyanine green fluorescent cholangiography in urgent and emergency laparoscopic cholecystectomy: a preliminary study after propensity score-matched study

IntroductionBile duct injury is a major complication of laparoscopic cholecystectomy (LC). Indocyanine green near-infrared fluorescence cholangiography (ICG-NIFC) is a well-recognized technique who provides an intraoperative mapping of the biliary system.MethodsAll patients underwent urgent LC and randomly divided into two groups: in one group, only white light imaging was used and, in the ICG group, ICG was used. Due to the heterogeneity of our groups, a PSM was performed with a 1:1 PSM cohort.ResultsThe use of ICG clearly decreases the operation time (p value 0.002). The overall rate of intra- and post- operative complications was 4.17% and 15.8% respectively. Post-operative biliary duct injury trend decreases in ICG group and after the homogenization of the 2 cohorts, the intra- and post- operative complications (including vascular and biliary duct injury) results changed with a highest rate of complication in the cohort with no-ICG administration.The use of NIFC demonstrated a protective effect against intra- and post- operative complications and biliary duct injury (HR 0.037, p value 0.337 and HR 0.039, p value 0.647; HR 0.288; p value 0.05 and HR 0.635; p value 0.687, respectively).ConclusionsThe intra-operative use of NIFC showed a trend in the reduction of the rate of intra- and post-operative complications, the duration of surgery, and the length of hospital stay. ICG is a highly safe approach to urgent and emergency LC, as for elective LC, and could lead the surgeon to conduct the procedure more efficiently.

Near-infrared fluorescence cholangiography in dogs: A pilot study.

To determine the effect of indocyanine green (ICG) dose and timing of administration on near-infrared fluorescence (NIRF) imaging of the normal canine biliary tree. Preclinical prospective study. Eight purpose-bred beagles. The dogs were randomized to receive two of four intravenous ICG dose (low [L]:0.05 mg/kg or high [H]:0.25 mg/kg)/time (0 and 3 h prior to NIRF) combinations. NIRF images were collected every 10 min for 120 min. Target (cystic duct)-to-background (liver) ratios were calculated for all timepoints and compared. ICG cholangiography was successful in all dogs. The contrast ratio was above 1 in the L0 group by 20 min and reached its peak at 100 min. In the H0 group, the ratio was above 1 by 60 min and reached its peak at 90 min. Contrast ratios above 2 (fluorescence twice as bright in the cystic duct compared to the liver) were maintained from 180 to 300 min for L3 and H3 and was achieved after 80 min for L0. Low dose ICG provided better ratios early after injection compared to the high dose which remained highly concentrated in the liver tissue after injection. Both doses provided excellent visualization of the biliary tree at 3 h post injection, low dose ICG provided better ratios from 3 to 5 h post injection. Based on these results, 0.05 mg/kg of ICG administered at anesthetic premedication, or as early as 3 h prior to laparoscopic surgery should yield optimal fluorescence images. This study provides guidelines for NIRF cholangiography in clinically normal dogs.

Utility of near infrared fluorescent cholangiography in detecting biliary structures during challenging minimally invasive cholecystectomy.

Surgeons can minimize the risk of bile duct injury (BDI) during challenging mini-invasive cholecystectomy through technical standardization by means of a precise anatomical landmark identification (Critical View of Safety) and advanced technology for biliary visualization. Among these systems, the adoption of magnified stereoscopic 3-dimensional view provided by robotic platforms and near infrared fluorescent cholangiography (NIRF-C) is the most promising. In this prospective cohort study, we evaluated all consecutive minimally invasive cholecystectomies (laparoscopic and robotic) performed with NIRF-C between May 2022 and January 2023 at General Surgery Unit, Department of Health Sciences, University of Milan, San Paolo Hospital (Milan, Italy). Inclusions criteria were as follows: (1) acute cholecystitis (emergency group), (2) history of chronic cholecystitis or complicated cholelithiasis (deferred urgent group), (3) difficult cases (patients affected by cirrhosis, with scleroatrophic gallbladder or BMI > 35kg/m2). For each group, the detection rate and visualization order of the main biliary structures were reported (cystic duct, CD; common hepatic duct, CHD; common bile duct, CBD; and CD-CHD junction). A total of 101 consecutive patients were enrolled, including 83 laparoscopic and 18 robotic cholecystectomies. All patients were stratified into three subgroups: (a) emergency group (n = 33, 32.7%), (b) deferred urgent group (n = 46, 45.5%), (c) difficult group (n = 22, 21.8%). Visualization of at least one biliary structure was possible in 94.1% of cases (95/101). Interestingly, all four main structures were detected in 43.6% of cases (44/101). The CD was the structure identified most frequently, being recognized in 91/101 patients (90.1%), followed by CBD (83.2%), CHD (62.4%), and CD-CHD junction (52.5%). In the subset of patients that underwent emergency surgery for AC, the CD-CHD confluence was identified in only 45.5% of cases. However, early and precise identification of CBD (75.8%) and CD (87.9%) allowed safe isolation, clipping, and transection of the cystic duct. In the deferred urgent group, the CBD and the CD were easily identified as first structure in a high percentage of cases (65.2% and 41.3% respectively), whereas the CD-CHD junction was the third structure to be identified in 67.4% of cases, the highest value among the three subgroups. In the difficult group, NIRF-C did not prove to be a useful tool for biliary visualization. The rates of failure of visualization were elevated: CBD (27.3%), CD (18.2%), CHD (54.5%), and CD-CHD (68.2%). NIRF-C is a powerful real-time diagnostic tool to detect CBD and CD during minimally invasive cholecystectomy, especially when inflammation due to acute or chronic cholecystitis subverted the anatomy of the hepatoduodenal ligament.

Indocyanine green fluorescent cholangiography improves the clinical effects of difficult laparoscopic cholecystectomy.

Near-infrared fluorescent cholangiography (NIRFC) with indocyanine green (ICG) as the developer yields clear visualization of the extrahepatic bile ducts and is effective in identifying key structures. Here, we analyzed and compared the surgical outcomes of fluorescent and conventional laparoscopy in cholecystectomy of various difficulties and then assessed the value of NIRFC. This retrospective study collected clinical data from partial patients who underwent laparoscopic cholecystectomy (LC) at the Department of Hepatobiliary and Pancreatic Surgery, Zhongnan Hospital of Wuhan University between 2020 and 2021. The study subjects were classified into ICG-assisted and white-light laparoscopy. Two cohorts with homogeneous baseline status were selected based on 1:1 ratio propensity score matching (PSM). Multivariate logistic regression analysis was performed to predict independent risk factors for LC difficulty. Thereafter, the matched cases were classified into difficult and easy subgroups by combining difficulty score and gallbladder disease type, and then the surgical outcomes of the two groups were compared. This study included a total of 624 patients. The patients were classified into the ICG group (n = 218) and the non-ICG group (n = 218) after a 1:1 ratio PSM. Our data showed significant differences between the groups in operative time (P = 0.020), blood loss (P = 0.016), length of stay (P = 0.036), and adverse reaction (P = 0.023). Stratified analysis demonstrated that ICG did not significantly improve the surgical outcomes in simple cases (n = 208). On the other hand, in difficult cases (n = 228), NIRFC shortened operative time (P = 0.003) and length of stay (P = 0.015), reduced blood loss (P = 0.028) and drain placement rate (P = 0.015), and had fewer adverse reactions (P = 0.023). The data showed that five cases were converted to laparotomy while two cases had minor bile leaks in the non-ICG group. There was no bile duct injury (BDI) in all the cases. Furthermore, high BMI, history of urgent admission and abdominal surgery, palpable gallbladder, thickened wall, and pericholecystic collection were risk factors for surgical difficulty. ICG-assisted NIRFC provides real-time biliary visualization. In complicated conditions such as acute severe inflammation, dense adhesions, and biliary variants, the navigating ability of fluorescence can enhance the operation progress, reduce the possibility of conversion or serious complications, and improve the efficiency and safety of difficult LC.

Dose and administration time of indocyanine green in near-infrared fluorescence cholangiography during laparoscopic cholecystectomy (DOTIG): study protocol for a randomised clinical trial

BackgroundOne of the most severe complications in laparoscopic cholecystectomy (LC) is intraoperative bile duct injury (BDI). Despite its low incidence, the medical implications for the patient can be serious. Besides,...

Efficacy of near-infrared fluorescence cholangiography using indocyanine green in laparoscopic cholecystectomy: A retrospective study.

While laparoscopy has been the standard procedure for gallstone treatment, recent advances including the use of indocyanine green (ICG) in laparoscopic cholecystectomy have made it easier to understand the biliary tree and reduce the risk of bile duct injury. In this retrospective study, we aim to determine the efficacy of ICG in near-infrared fluorescence cholangiography (NIRFC) for visualising biliary anatomy. A total of 90 patients with the symptoms of cholelithiasis were enrolled for this retrospective study. All the patients underwent cholecystectomy approximately 53.8 min (40-90 min) after the intravenous administration of mean volume 1.6 ml (1-2 ml) ICG. The surgeons used NIRFC along with ICG for real-time visualisation of biliary anatomy. The mean operative time for the surgery was 65.7 min (25-120 min) with no post-surgical complications observed in the patients. The average length of stay was 2 days (1-3 days). ICG usage with NIRFC enabled identification of cystic duct, common hepatic and common bile duct, the junction between common hepatic and bile duct, right and left hepatic duct in 87.7%, 94.4%, 80% and 14.4% of cases, respectively. ICG fluorescence allowed successful visualisation of at least 1 biliary structure in 100% of cases.

Efficacy of Near Infrared Fluorescent Cholangiography (NIRF-C) in Detecting Biliary Structures during Challenging Laparoscopic and Robotic Cholecystectomies

Efficacy of Near Infrared Fluorescent Cholangiography (NIRF-C) in Detecting Biliary Structures during Challenging Laparoscopic and Robotic Cholecystectomies

Efficacy and Safety of Near-Infrared Florescence Cholangiography Using Indocyanine Green in Laparoscopic Cholecystectomy: A Systematic Review and Meta-Analysis.

Background: Achieving critical view of safety is a key for a successful laparoscopic cholecystectomy (LC) procedure. Near-infrared fluorescence cholangiography using indocyanine green (NIF-ICG) in LC has been extensively used and accepted as beneficial auxiliary tool to visualize extrahepatic biliary structures intraoperatively. This study aimed to analyze its safety and efficacy. Materials and Methods: Searching for potential articles up to March 25, 2022 were conducted on PubMed, Europe PMC, and ClinicalTrials.gov databases. Articles on the near infrared fluorescence during laparoscopy cholecystectomy were collected. Review Manager 5.4 software was utilized to perform the statistical analysis. Results: Twenty-two studies with a total of 3457 patients undergo LC for the analysis. Our meta-analysis revealed that NIF-ICG technique during LC was associated with shorter operative time (Std. Mean Difference -0.86 [95% confidence interval (CI) -1.49 to -0.23], P = .007, I2 = 97%), lower conversion rate (risk ratio [RR] 0.28 [95% CI 0.16-0.50], P < .0001, I2 = 0%), higher success in identification of cystic duct (CD) (RR 1.24 [95% CI 1.07-1.43], P = .003, I2 = 94%), higher success in identification of common bile duct (CBD) (RR 1.31 [95% CI 1.07-1.60], P = .009, I2 = 90%), and shorter time to identify biliary structures (Std. Mean Difference -0.52 [95% CI -0.78 to -0.26], P < .0001, I2 = 0%) compared with not using NIF-ICG. Conclusions: NIF-ICG technique beneficial for early real-time visualization of biliary structure, shorter operative time, and lower risk of conversion during LC. Larger randomized clinical trials are still needed to confirm the results of our study.

Use of fluorescence imaging and indocyanine green during laparoscopic cholecystectomy: Results of an international Delphi survey

BackgroundPublished empirical data have increasingly suggested that using near-infrared fluorescence cholangiography during laparoscopic cholecystectomy markedly increases biliary anatomy visualization. The technology is rapidly evolving, and different equipment and doses may be used. We aimed to identify areas of consensus and nonconsensus in the use of incisionless near-infrared fluorescent cholangiography during laparoscopic cholecystectomy. MethodsA 2-round Delphi survey was conducted among 28 international experts in minimally invasive surgery and near-infrared fluorescent cholangiography in 2020, during which respondents voted on 62 statements on patient preparation and contraindications (n = 12); on indocyanine green administration (n = 14); on potential advantages and uses of near-infrared fluorescent cholangiography (n = 18); comparing near-infrared fluorescent cholangiography with intraoperative x-ray cholangiography (n = 7); and on potential disadvantages of and required training for near-infrared fluorescent cholangiography (n = 11). ResultsExpert consensus strongly supports near-infrared fluorescent cholangiography superiority over white light for the visualization of biliary structures and reduction of laparoscopic cholecystectomy risks. It also offers other advantages like enhancing anatomic visualization in obese patients and those with moderate to severe inflammation. Regarding indocyanine green administration, consensus was reached that dosing should be on a milligrams/kilogram basis, rather than as an absolute dose, and that doses >0.05 mg/kg are necessary. Although there is no consensus on the optimum preoperative timing of indocyanine green injections, the majority of participants consider it important to administer indocyanine green at least 45 minutes before the procedure to decrease the light intensity of the liver. ConclusionNear-infrared fluorescent cholangiography experts strongly agree on its effectiveness and safety during laparoscopic cholecystectomy and that it should be used routinely, but further research is necessary to establish optimum timing and doses for indocyanine green.

Near-infrared fluorescence cholangiography at a very low dose of indocyanine green: quantification of fluorescence intensity using a colour analysis software based on the RGB color model.

Indocyanine green (ICG) near-infrared fluorescence cholangiography (NIRF-C) is widely used to visualize the biliary tract during laparoscopic cholecystectomy (LC). However, the ICG dose and its dosing time vary in the literature so there is not a standard ICG protocol. The objectives of this descriptive prospective study were to demonstrate that NIRF-C at a very low dose of ICG provides good visualization of the extrahepatic biliary tree while avoiding hepatic hyperluminescence and to assess the surgeon-perceived benefit. Furthermore, another additional aim was quantifying the amount of ICG dye in the liver tissue and biliary tract through a green colour intensity (GCI) analysis according to red green blue (RGB) color model and correlating it to surgeon-perceived benefit. Forty-four patients were scheduled for LC. We recorded demographics, surgical indication, intraoperative details, adverse reactions to ICG, hepatic hyperluminescence, visualization of the cystic duct (CD), the common bile duct (CBD) and the cystic duct-bile duct junction (CDBDJ) before and after dissection ofCalot's triangle, operation time, surgical complications and subjective surgeon data. For all procedures, a unique dose of 0.25mg of ICG was administered intravenously during the anaesthetic induction. ICG NIRF-C was performed using the overlay mode of the VISERA ELITE II Surgical Endoscope in all surgeries. Video recordings of all 44 LC were reviewed. Using a color analysis software, the GCI of CBD versus adjacent liver tissue was calculated using RGB color model. ICG NIRF-C was performed in all 44 cases. The mean operation time was 45 ± 15min. There were no bile duct injuries (BDIs) or allergic reactions to ICG. The postoperative course was uneventful in all of cases. The mean postoperative hospital stay was 28 ± 4h. ICG NIRF-C identified the CBD in 100% of the patients, the CD in 71% and the CDBDJ in 84%, with a surgeon satisfaction of 4/5 or 5/5 in almost 90% of surgeries based on a visual analogue scale (VAS). No statistically significant differences were found in the visualization of the biliary structures after the dissection of Calot's triangle in obese patients or with gallbladder inflammation. Furthermore, 25% of patients with a BMI ≥ 30, 27% of patients with a Nassar grade ≥ 3 and 21% of patients with gallbladder inflammation had a VAS score 5/5 compared to 6% of patients with a BMI < 30 (p = 0.215), 6% of patients with a Nassar grade < 3 (p = 0.083) and none of the patients without gallbladder inflammation (p = 0.037). Measured pixel GCI of CBD was higher than adjacent hepatic tissue for all cases regardless of the degree of gallbladder inflammation, the Nassar scale grades or the patient's BMI (p < 0.0001). In addition, a significant correlation was observed between surgeon-perceived benefit and the amount of ICG dye into the CBD according the RGB color model (p < 0.0001). ICG NIRF-C at a very low dose of ICG (0.25mg of ICG 20min before surgery) enables the real-time identification of biliary ducts, thereby avoiding the hepatic hyperluminescence even in cases of obese patients or those with gallbladder inflammation.

Study of Learning Curve in a Surgeon for Near-Infrared Fluorescence Cholangiography During Laparoscopic Cholecystectomy-A Retrospective Evaluation.

Near-infrared indocyanine green fluorescence cholangiography (NIRF) has shown promising results on delineating extra-hepatic biliary anatomy during laparoscopic cholecystectomy to avoid bile duct injury. However its routine usage remains in question. In this study, the technique was evaluated further with learning curve estimation and learning factors were observed. One hundred ninety-nine cases which underwent laparoscopic cholecystectomy for acute or chronic cholecystitis within a 2-year period including 51 cases with initial use of NIRF by 2 surgeons were studied retrospectively. The learning curve was evaluated for a surgeon as primary objective. A case-matched comparison of the operative time between NIRF and conventional group, in terms of acute and chronic cholecystitis was also conducted as a secondary calculation. Learning curve was evaluated with 61% learning rate for NIRF experience. Cysto-biliary junction non-illuminated cases under fluorescent view, had mean operative time of 80.83 ± 22.82min, which was shorter than the cysto-biliary junction illuminated cases. The NIRF group exhibited longer operative time compared with the conventional group with mean difference of 34.39min (significant at P < .05). While the initial learning phase might be affected by surgeons' behavior and attitude, our results may provide a reference to learn at one's own pace and to employ NIRF teaching strategies during surgical training programs to overcome the initial phase during training period itself and facilitate universal achievement.

Image-guided laparoscopic cholecystectomy using indocyanine green fluorescence cholangiography: what is the optimal time of administration?

Introduction Near-infrared (NIR) fluorescent cholangiography (FC) using indocyanine green (ICG) in laparoscopic cholecystectomy (LC) has been used as a technique for real-time visualization of bile ducts for approximately ten years; however, no standard protocol has been determined. This study aimed to determine the optimal time of administration of ICG. Material and methods In this prospective study, patients (n = 30) indicated for LC were divided into two groups. The first group received ICG 1 h before anesthesia at a dose of 0.1 mg/kg (1 h group), whereas the other group received ICG immediately after anesthesia with the same dose (0 h group). Results The rates of identification of the cystic duct (CD) and common bile duct (CBD) using NIR FC before and after dissection of Calot’s triangle were comparable between the two groups. The fluorescence intensity ratios of CD/Liver and CBD/Liver were significantly higher in the 1 h group (2.2 vs. 0.49 and 2.1 vs. 0.38, respectively, p < .001) with minimal background liver fluorescence interference in the 1 h group. Conclusions The study illustrates that administration of ICG 1 h before surgery with a dose of 0.1 mg/kg allows superior visualization of the extrahepatic bile ducts with minimal fluorescence interference from the background liver.

Application of Fluorescence Image Guided Cholangiography for the Assessment of Biliary Anatomy in Patients with Acute Cholecystitis

Introduction: Laparoscopic cholecystectomy (LC) for acute cholecystitis (AC) tends to be difficult even in experienced surgeons hands. Near-Infrared Fluorescent Cholangiography (NIRF-C) has shown to increase the visualization of biliary ducts. The aim of this study is to assess fluorescence effect for detection of biliary anatomy in patients with AC.

Laparoscopic remnant cholecystectomy for calculi in the remnant gallbladder following subtotal-cholecystectomy: a report of two cases

Two cases of laparoscopic remnant cholecystectomy using near-infrared fluorescence cholangiography (NIFC) for remnant gallbladder calculi following subtotal-cholecystectomy are reported. Case 1: a 36-year-old woman was referred to our hospital with acute abdomen. Computed tomography showed remnant gallbladder calculi, with detected no other findings as the cause of the abdominal pain. For intraoperative exploration of the biliary anatomy, 0.25 mg/kg of indocyanine green (ICG) was administered intravenously the day before the operation. NIFC clearly showed the common bile duct and enabled safe laparoscopic remnant cholecystectomy. She was free from symptoms after the operation. Case 2: a 40-year-old woman was referred to our hospital with epigastralgia due to remnant gallbladder calculi after open cholecystectomy. ICG was administered intravenously the day before the operation. Severe adhesions were observed in the upper abdominal cavity and there was tight adherence of the duodenum to the remnant gallbladder. NIFC showed a clear margin that appeared to be the margin between the duodenum and remnant gallbladder. However, dissection of the margin observed by NIFC caused perforation of the duodenum. The clear margin seen with NIFC was likely due to visualization of the gallbladder through the duodenum. Although NIFC is a useful modality for confirming the intraoperative biliary anatomy, it is important not to rely too heavily on NIFC alone, which may lead to misinterpretation of the anatomy.

The role of indocyanine green cholangiography in minimally invasive surgery.

Near-infrared fluorescent cholangiography (NIFC) using indocyanine green (ICG) is increasingly used to aid in the identification of extrahepatic biliary anatomy. The use of ICG cholangiography for laparoscopic cholecystectomy is suggested to be safe and feasible. This article aimed at reviewing the dosage and timing of the intravenous administration of ICG, its efficacy and potential usage. MEDLINE and PubMed searches were performed using the key words "fluorescent cholangiography," "ICG cholangiography," "near-infrared fluorescent cholangiography" and "laparoscopic cholecystectomy" to identify relevant articles published in English during the years of 2010 to 2020. Reference lists from the articles were reviewed to identify additional pertinent articles. Several factors can influence the quality of the fluorescence imaging, including the dose and timing of ICG injection, liver function, the thickness of fatty tissue and the presence of inflamed tissues due to acute pathology. Various devices tested also have a different sensitivity to the fluorescence signal. RCTs showed fluorescence cholangiography were comparable to traditional intraoperative cholangiogram in visualizing the extrahepatic biliary anatomy. However, there is still no consensus in the dosing of ICG and the time interval between ICG injection and detection of biliary fluorescence. Fluorescence cholangiography's ability to enhance such visualization can potentially reduce bile duct injury risks and shorten the operative time. However, no valuable data for bile duct injury prevention or detection could be retrieved. NIFC is demonstrated as a safe, non-irradiating technique to identify and aid in the visualization of extrahepatic biliary anatomy. Laparoscopic cholecystectomy with real-time NIFC enables a better visualization and identification of biliary anatomy and therefore it is potentially as a means of increasing the safety of laparoscopic cholecystectomy. Whether this translates into reducing complication rates must still be determined. The dosage and timing of the intravenous administration of ICG relative to the operative procedure still requires optimization to ensure reliable images.

P11: NEAR INFRARED FLUORESCENT CHOLANGIOGRAPHY IN LAPAROSCOPIC CHOLECYSTECTOMY: A SINGLE CENTRE FEASIBILITY STUDY. THE OPTIMUM DOSING REGIME, LIMITATIONS AND WHERE NEXT?

Abstract Introduction This study explored near-infrared fluorescent cholangiography (NIRFC) with Indocyanine Green (ICG) during laparoscopic cholecystectomy (LC) surgery in a tertiary referral hepatobiliary unit. ICG binds to albumin and is excreted in bile. NIRFC utilises the fluorescent and excretory properties of ICG to provide dynamic extrahepatic bile duct mapping during LC. Method Non-randomised single centre feasibility study. Twenty-two participants were sequentially allocated to four dosing subgroups prior to NIRFC assisted LC. Each received a single intravenous dose of ICG prior to LC with the Stryker Novadaq NIR laparoscope. The biliary anatomy was assessed with NIRFC at three time-points, detection was compared to radiological cholangiogram where available and surgeon satisfaction was assessed. Result Eight participants received 2.5mg ICG 20-40min before surgery, four 0.25mg/kg 20-40min, five 90min – 180min and five 12 – 36 hour pre-operatively. Average age 50 years (S.D±15), BMI 27.5m2 (S.D±3.6), 6/22 were acute LC procedures. The prolonged dosing interval produced increased extrahepatic biliary structure identification (p = 0.016), reduced noise to signal ratio and was consistently preferred by the operating surgeon. NIRFC was inferior to radiological cholangiogram (n = 10) (p = 0.014) for bile duct mapping. We observed iatrogenic bile spillage saturating the field and obscuring structure differentiation and peri-hilar inflammation impeding fluorescent detection in acute LC. Conclusion The dosing regimen 0.25mg/kg ICG 12 to 36 hours prior to surgery provides optimum NIRFC structure visualisation. Fluorescent tissue penetrance is limited in acute peri-hilar inflammation. More research in to the efficiency of NIRFC in emergency LC is required. Take-home message An intravenous dose of 0.25mg/kg of Indocyanine Green 12 to 36 hours before surgery is the optimum dosing regimen for increased extra-hepatic bile duct structures with near infrared fluorescent cholangiography. The role of NIRFC in acute laparoscopic cholecystectomy surgery remains ill-defined.