Techniques of Fluorescence Cholangiography During Laparoscopic Cholecystectomy for Better Delineation of the Bile Duct Anatomy

Effects of Indocyanine Green (ICG) Imaging-Assisted Cholecystectomy on Intraoperative and Postoperative Complications: A meta-Analysis

BACKGROUND

Accurate recognition of Calot's triangle during cholecystectomy is important in preventing intraoperative and postoperative complications. The use of indocyanine green (ICG) fluorescence imaging has become increasingly prevalent in cholecystectomy procedures. Our study aimed to evaluate the specific effects of ICG-assisted imaging in reducing complications.

MATERIALS AND METHODS

A comprehensive search of databases including PubMed, Web of Science, Europe PMC, and WANFANGH DATA was conducted to identify relevant articles up to July 5, 2023. Review Manager 5.3 software was applied to statistical analysis.

RESULTS

Our meta-analysis of 14 studies involving 3576 patients compared the ICG group (1351 patients) to the control group (2225 patients). The ICG group had a lower incidence of postoperative complications (4.78% vs 7.25%; RR .71; 95%CI: .54-.95; P = .02). Bile leakage was significantly reduced in the ICG group (.43% vs 2.02%; RR = .27; 95%CI: .12-.62; I2 = 0; P = .002), and they also had a lower bile duct drainage rate (24.8% vs 31.8% RR = .64, 95% CI: .44-.91, P = .01). Intraoperative complexes showed no statistically significant difference between the 2 groups (1.16% vs 9.24%; RR .17; 95%CI .03-1.02), but the incidence of intraoperative bleeding is lower in the ICG group.

CONCLUSION

ICG fluorescence imaging-assisted cholecystectomy was associated with a range of benefits, including a lower incidence of postoperative complications, decreased rates of bile leakage, reduced bile duct drainage, fewer intraoperative complications, and reduced intraoperative bleeding.

Feasibility, safety, and efficacy of intraoperative magnetic resonance imaging-guided hepatectomy for small hepatocellular carcinoma: A retrospective study

Advancements in diagnostic modalities, such as enhanced magnetic resonance imaging, provide increased opportunities for identifying small hepatocellular carcinoma that is undetectable on preoperative ultrasonography. Whether it is acceptable to leave these lesions untreated is uncertain. This study aimed to evaluate the safety and efficacy of intraoperative magnetic resonance imaging-guided hepatectomy using new navigation systems. This study was conducted between July 2019 and January 2023. We retrospectively studied the clinicopathological features and prognoses of patients with small hepatocellular carcinoma who underwent curative intraoperative magnetic resonance imaging-guided hepatectomy. We evaluated 23 patients (median age, 75 years), among whom 20 (87.0%) were males. Seven (30.4%) and 15 (65.2%) patients had liver cirrhosis and a history of hepatectomy, respectively. The median size of the target lesions was 9 mm, with a median distance of 6 mm from the liver surface. Despite being undetectable preoperatively on contrast-enhanced ultrasonography, all lesions were identified using intraoperative magnetic resonance imaging. Based on pathological findings, 76.0% of the lesions were malignant. The complete resection rate was 100%, and tumor-free margins were confirmed in 96.0% of the patients. Intraoperative magnetic resonance imaging-guided hepatectomy is safe and effective in identifying and resecting small hepatocellular carcinoma lesions that are undetectable on preoperative ultrasonography.

Near-infrared fluorescence cholangiography in dogs: A pilot study

OBJECTIVE

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.

STUDY DESIGN

Preclinical prospective study.

ANIMALS

Eight purpose-bred beagles.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

CLINICAL SIGNIFICANCE

This study provides guidelines for NIRF cholangiography in clinically normal dogs.

[Experience of indocyanine green use in acute calculous cholecystitis]

OBJECTIVE

To assess the safety and effectiveness of the indocyanine green use in acute cholecystitis for identification of anatomical variants of the biliary tree; prevention and timely detection of intraoperative complications.

MATERIAL AND METHODS

The medication of indocyanine green made by OOO «Ferment» domestic manufacturer was used. The drug dose from 2.5 mg to 10 mg was applied according to studied materials (8). Time of the surgery beginning was from 2 to 6 hours after intravenous injection of aqueous solution, respectively. In addition, it has been established that the optimal drug dose is 5 mg. The surgery should be performed not earlier than 3 hours after, but no later than 6 hours. This allows to achieve the most comfortable fluorescence of the extrahepatic biliary tract. The drug concentration in the liver cells decreases by this time and increases in the biliary tract. It is not always possible to perform the operation strictly within the specified time limit considering the urgency of the surgical intervention. In this connection, the surgery was carried out not earlier than 3 hours after the drug injection, but not later than 6 hours. Endoscopic equipment with the ability to display near-infrared fluorescence was used. A laser light source with a wavelength of 820 nm in the Arthrex imaging system with 4K resolution as well as the Olympus imaging system with HD resolution were used for fluorescence excitation.

RESULTS

The implementation of intraoperative fluorescent navigation with indocyanine green contributes to the improvement of safety and effectiveness of surgical treatment through visualization of topography and identification of anatomical variants of the biliary tree; possibilities of prevention and timely detection of intraoperative complications. The use of indocyanine green allows to intraoperatively reveal atypical location and different variations of the extrahepatic biliary tract.

Indocyanine Green in Bariatric Surgery: a Systematic Review

Indocyanine green (ICG) is a fluorescent dye that can be used intraoperatively to assess tissue perfusion, as well as perform leak testing. This study aims to summarize published manuscripts on outcomes of ICG use and reduction of complications compared to traditional leak test and tissue perfusion evaluation. A PubMed search using "ICG and bariatric surgery," "ICG and gastric sleeve," "ICG and gastric bypass," and "ICG and revisional bariatric surgery" was performed. The proportion of patients who underwent an intraoperative decision change due to ICG was 3.8% (95% CI: 2.0 to 7.2%). ICG fluorescent imaging in bariatric surgery is a valuable tool, and further studies are needed to confirm its utility for routine use in both standard or complex cases (PROSPERO #418126).

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.

Investigation of the optimal indocyanine green dose in real-time fluorescent cholangiography during laparoscopic cholecystectomy with an ultra-high-definition 4K fluorescent system: a randomized controlled trial

This study aimed to investigate the indocyanine green (ICG) dose in real-time fluorescent cholangiography during laparoscopic cholecystectomy (LC) with a 4K fluorescent system. A randomized controlled clinical trial was conducted in patients who underwent LC for treatment of cholelithiasis. Using the OptoMedic 4K fluorescent endoscopic system, we compared four different doses of ICG (1, 10, 25, and 100 µg) administered intravenously within 30 min preoperatively and evaluated the fluorescence intensity (FI) of the common bile duct and liver background and the bile-to-liver ratio (BLR) of the FI at three timepoints: before surgical dissection of the cystohepatic triangle, before clipping the cystic duct, and before closure. Forty patients were randomized into four groups, and 33 patients were fully analyzed, with 10 patients in Group A (1 µg), 7 patients in Group B (10 µg), 9 patients in Group C (25 µg), and 7 patients in Group D (100 µg). The preoperative baseline characteristics were compared among groups (p > 0.05). Group A showed no or minimal FI in the bile duct and liver background, while Group D showed extremely high FIs in the bile duct and in the liver background at the three timepoints. Groups B and C presented with visible FI in the bile duct and low FI in the liver background. With increasing ICG doses, the FIs in the liver background and bile duct gradually increased at the three timepoints. The BLR, however, showed no increasing trend with an increasing ICG dose. A relatively high BLR on average was found in Group B, without a significant difference compared to the other groups (p > 0.05). An ICG dose ranging from 10 to 25 µg by intravenous administration within 30 min preoperatively was appropriate for real-time fluorescent cholangiography in LC with a 4K fluorescent system. Registration: This study was registered in the Chinese Clinical Trial Registry (ChiCTR No: ChiCTR2200064726).

Identification of the ideal weight-based indocyanine green dose for fluorescent cholangiography

BACKGROUND

Ideal visualization of fluorescent cholangiography during laparoscopic cholecystectomy is when maximum fluorescence into biliary ducts and absent signal into liver parenchyma, defined as "signal to background ratio" (SBR), is obtained. Such condition is mainly dependent by indocyanine green (ICG) dose and timing. The aim of this study was to identify the ideal ICG dose to obtain the best possible intraoperative visualization of the extra-hepatic biliary tree.

METHODS

The first part of the study was used to define a range of small weight-based ICG dosages using the mathematical function bisection method. During the second part of the study, the midpoint dose of the identified range, was tested in 50 consecutive cholecystectomies using a laser-based fluorescence laparoscopic camera (SynergyID system by Arthrex, Naples, FL, USA). Timing administration was set at 1 h before surgery, since this is the most common situation in clinical practice. Fluorescence intensity of bile ducts and liver parenchyma were assessed both subjectively, by blinded operative surgeon, as well as objectively, using an image analysis software (Fiji plugin), before and after Calot's triangle dissection.

RESULTS

Fourteen patients were included in the first part of the study and ICG dose between 0.01191406 and 0.0119873 mg/kg was identified. The second part confirmed previous results after testing the dosage equal to 0.0119 mg/kg (midpoint of the defined range) in 50 consecutive cholecystectomies. Cystic duct was identified in 66 and 100% of cases before and after dissection of Calot's triangle respectively. On the other hand, common bile duct was identified in 82 and 92% before and after dissection respectively. Subjective and objective SBRs confirmed the benefit of the identified ICG dose.

CONCLUSION

ICG dose calculated by 0.0119 mg/kg administered one hour before surgery allows an ideal intraoperative visualization of the extra-hepatic biliary tree.

REGISTRATION NUMBER

ISRCTN10190039.

The Wonder Dye: Uses and Implications of Indigocyanine Green in Various Surgeries

Indigocyanine green (ICG) is a fluorophore dye that has been extensively used in recent modern times for bioimaging in numerous surgeries to aid in easier identification of occult and often tricky-to-find anatomical structures. Surgery becomes complex and challenging due to multiple anatomical anomalies, pathological fibrosis, obesity, or previous surgeries. To overcome these obstacles in surgery, the surgeon yearns to know the structures present beyond their white light vision so that while dissecting the organ, they can avoid injuring the critical systems in the vicinity of dissection. Near-infrared (NIR) imaging aids in visualising the tissues at depth/in the area of dissection, thereby preventing any possible surgical catastrophes due to them inadvertently damaging surrounding vital structures. Various advantages in surgeries like gastric sleeve surgery, lymph node and tumour detection, localisation of ureters and biliary tracts, and intraoperative tissue perfusion of flaps have been described in this study. This review article aims to compile a short list of utilities of ICG with NIR imaging in various surgical interventions. The merits and demerits of this imaging technique have been noted. The study points out the uses of ICG fluorescence imaging under different surgical fronts. This review article concludes by comparing the results of studies performed by various authors. Results have been compared to conventional surgical modalities.

Clinical application of machine learning and computer vision to indocyanine green quantification for dynamic intraoperative tissue characterisation: how to do it

INTRODUCTION

Indocyanine green (ICG) quantification and assessment by machine learning (ML) could discriminate tissue types through perfusion characterisation, including delineation of malignancy. Here, we detail the important challenges overcome before effective clinical validation of such capability in a prospective patient series of quantitative fluorescence angiograms regarding primary and secondary colorectal neoplasia.

METHODS

ICG perfusion videos from 50 patients (37 with benign (13) and malignant (24) rectal tumours and 13 with colorectal liver metastases) of between 2- and 15-min duration following intravenously administered ICG were formally studied (clinicaltrials.gov: NCT04220242). Video quality with respect to interpretative ML reliability was studied observing practical, technical and technological aspects of fluorescence signal acquisition. Investigated parameters included ICG dosing and administration, distance-intensity fluorescent signal variation, tissue and camera movement (including real-time camera tracking) as well as sampling issues with user-selected digital tissue biopsy. Attenuating strategies for the identified problems were developed, applied and evaluated. ML methods to classify extracted data, including datasets with interrupted time-series lengths with inference simulated data were also evaluated.

RESULTS

Definable, remediable challenges arose across both rectal and liver cohorts. Varying ICG dose by tissue type was identified as an important feature of real-time fluorescence quantification. Multi-region sampling within a lesion mitigated representation issues whilst distance-intensity relationships, as well as movement-instability issues, were demonstrated and ameliorated with post-processing techniques including normalisation and smoothing of extracted time-fluorescence curves. ML methods (automated feature extraction and classification) enabled ML algorithms glean excellent pathological categorisation results (AUC-ROC > 0.9, 37 rectal lesions) with imputation proving a robust method of compensation for interrupted time-series data with duration discrepancies.

CONCLUSION

Purposeful clinical and data-processing protocols enable powerful pathological characterisation with existing clinical systems. Video analysis as shown can inform iterative and definitive clinical validation studies on how to close the translation gap between research applications and real-world, real-time clinical utility.

Laparoscopic fluorescence imaging technique for visualizing biliary structures using sodium fluorescein: the result of a preclinical study in a porcine model

Purpose

Near-infrared fluorescence imaging has been recently applied in the field of hepatobiliary surgery. Our objective was to apply blue-light fluorescence cholangiography during laparoscopic surgery. Therefore, we designed a preclinical study to evaluate the feasibility of using blue-light fluorescence for cholangiography in a porcine model.

Methods

Five millimeters of sodium fluorescein (SF) solution was administered into the gallbladder of 20 male 3-way crossbred (Landrace × Yorkshire × Duroc) pigs in laparoscopic approach. The biliary tree was observed under blue light (a peak wavelength of 450 nm) emitted from a commercialized light-emitting diode (LED) light source (XLS1 extreme, Chammed).

Results

In 18 of 20 porcine models, immediately after SF solution was administered into the gallbladder, it was possible to visualize the biliary tree under blue light emitted from the LED light source.

Conclusion

This study provided a preclinical basis for using blue-light fluorescence cholangiography using SF in laparoscopic surgery. The clinical feasibility of blue-light fluorescence imaging techniques for laparoscopic cholecystectomy remained to be demonstrated.

Evaluating clinical near-infrared surgical camera systems with a view to optimizing operator and computational signal analysis

SIGNIFICANCE

As clinical evidence on the colorectal application of indocyanine green (ICG) perfusion angiography accrues, there is also interest in computerizing decision support. However, user interpretation and software development may be impacted by system factors affecting the displayed near-infrared (NIR) signal.

AIM

We aim to assess the impact of camera positioning on the displayed NIR signal across different open and laparoscopic camera systems.

APPROACH

The effects of distance, movement, and target location (center versus periphery) on the displayed fluorescence signal of different systems were measured under electromagnetic stereotactic guidance from an ICG-albumin model and in vivo during surgery.

RESULTS

Systems displayed distinct fluorescence performances with variance apparent with scope optical lens configuration (0 deg versus 30 deg), movement, target positioning, and distance. Laparoscopic system readings fitted inverse square function distance-intensity curves with one device and demonstrated a direction dependent sigmoid curve. Laparoscopic cameras presented central targets as brighter than peripheral ones, and laparoscopes with angled optical lens configurations had a diminished field of view. One handheld open system also showed a distance-intensity relationship, whereas the other maintained a consistent signal despite distance, but both presented peripheral targets brighter than central ones.

CONCLUSIONS

Optimal clinical use and signal computational development requires detailed appreciation of system behaviors.

Deconstructing mastery in colorectal fluorescence angiography interpretation

INTRODUCTION

Indocyanine green fluorescence angiography (ICGFA) is commonly used in colorectal anastomotic practice with limited pre-training. Recent work has shown that there is considerable inconsistency in signal interpretation between surgeons with minimal or no experience versus those consciously invested in mastery of the technique. Here, we deconstruct the fluorescence signal patterns of expert-annotated surgical ICGFA videos to understand better their correlation and combine this with structured interviews to ascertain whether such interpretative capability is conscious or unconscious.

METHODS

For fluorescence signal analysis, expert-annotated ICGFA videos (n = 24) were quantitatively interrogated using a boutique intensity tracker (IBM Research) to generate signal time plots. Such fluorescence intensity data were examined for inter-observer correlation (Intraclass Correlation Coefficients, ICC) at specific curve milestones: the maximum fluorescence signal (Fmax), the times to both achieve this maximum (Tmax), as well as half this maximum (T1/2max) and the ratio between these (T1/2/Tmax). Formal tele-interview with contributing experts (n = 6) was conducted with the narrative transcripts being thematically mapped, plotted, and qualitatively analyzed.

RESULTS

Correlation by mathematical measures was excellent (ICC0.9-1.0) for Fmax, Tmax, and T1/2max (0.95, 0.938, and 0.925, respectively) and moderate (0.5-0.75) for T1/2/Tmax (0.729). While all experts narrated a deliberate viewing strategy, their specific dynamic signal appreciation differed in the manner of description.

CONCLUSION

Expert ICGFA users demonstrate high correlation in mathematical measures of their signal interpretation although do so tacitly. Computational quantification of expert behavior can help develop the necessary lexicon and training sets as well as computer vision methodology to better exploit ICGFA technology.

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

BACKGROUND

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.

METHOD

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 of Calot's triangle, operation time, surgical complications and subjective surgeon data. For all procedures, a unique dose of 0.25 mg 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.

RESULTS

ICG NIRF-C was performed in all 44 cases. The mean operation time was 45 ± 15 min. 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 ± 4 h. 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).

CONCLUSION

ICG NIRF-C at a very low dose of ICG (0.25 mg of ICG 20 min 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.

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.

Fluorescence Image-Guided Navigation Surgery Using Indocyanine Green for Hepatoblastoma

In the past decade, navigation surgery using fluorescent indocyanine green (ICG) dye for hepatoblastoma (HB) has been developed for the resection of primary or metastatic tumors. Since HB cells can take up ICG but cannot excrete it to the bile duct, ICG remains in the HB cells, which can be used for navigation by fluorescent activation. The complete resection of the primary tumor as well as metastatic tumors, along with appropriate neoadjuvant and adjuvant chemotherapy, is essential for cure. ICG fluorescence can detect microscopic residual lesions in the primary lesion and identify micro-metastases in the lung or other lesions; consequently, ICG navigation surgery may improve outcomes for patients with HB. The basic technique and recent advances in ICG navigation for HB surgery are reviewed.

Consensus Guidelines for the Use of Fluorescence Imaging in Hepatobiliary Surgery

OBJECTIVE

To establish consensus recommendations for the use of fluorescence imaging with indocyanine green (ICG) in hepatobiliary surgery.

BACKGROUND

ICG fluorescence imaging has gained popularity in hepatobiliary surgery in recent years. However, there is varied evidence on the use, dosage, and timing of administration of ICG in clinical practice. To standardize the use of this imaging modality in hepatobiliary surgery, a panel of pioneering experts from the Asia-Pacific region sought to establish a set of consensus recommendations by consolidating the available evidence and clinical experiences.

METHODS

A total of 13 surgeons experienced in hepatobiliary surgery and/or minimally invasive surgery formed an expert consensus panel in Shanghai, China in October 2018. By the modified Delphi method, they presented the relevant evidence, discussed clinical experiences, and derived consensus statements on the use of ICG in hepatobiliary surgery. Each statement was discussed and modified until a unanimous consensus was achieved.

RESULTS

A total of 7 recommendations for the clinical applications of ICG in hepatobiliary surgery were formulated.

CONCLUSIONS

The Shanghai consensus recommendations offer practical tips and techniques to augment the safety and technical feasibility of ICG fluorescence-guided hepatobiliary surgery, including laparoscopic cholecystectomy, liver segmentectomy, and liver transplantation.

Digital dynamic discrimination of primary colorectal cancer using systemic indocyanine green with near-infrared endoscopy

As indocyanine green (ICG) with near-infrared (NIR) endoscopy enhances real-time intraoperative tissue microperfusion appreciation, it may also dynamically reveal neoplasia distinctively from normal tissue especially with video software fluorescence analysis. Colorectal tumours of patients were imaged mucosally following ICG administration (0.25 mg/kg i.v.) using an endo-laparoscopic NIR system (PINPOINT Endoscopic Fluorescence System, Stryker) including immediate, continuous in situ visualization of rectal lesions transanally for up to 20 min. Spot and dynamic temporal fluorescence intensities (FI) were quantified using ImageJ (including videos at one frame/second, fps) and by a bespoke MATLAB® application that provided digitalized video tracking and signal logging at 30fps (Fluorescence Tracker App downloadable via MATLAB® file exchange). Statistical analysis of FI-time plots compared tumours (benign and malignant) against control during FI curve rise, peak and decline from apex. Early kinetic FI signal measurement delineated discriminative temporal signatures from tumours (n = 20, 9 cancers) offering rich data for analysis versus delayed spot measurement (n = 10 cancers). Malignant lesion dynamic curves peaked significantly later with a shallower gradient than normal tissue while benign lesions showed significantly greater and faster intensity drop from apex versus cancer. Automated tracker quantification efficiently expanded manual results and provided algorithmic KNN clustering. Photobleaching appeared clinically irrelevant. Analysis of a continuous stream of intraoperatively acquired early ICG fluorescence data can act as an in situ tumour-identifier with greater detail than later snapshot observation alone. Software quantification of such kinetic signatures may distinguish invasive from non-invasive neoplasia with potential for real-time in silico diagnosis.

Bismuth Classification of Bile Duct Injury and Its Association with Increasing 30 Days Mortality after Revision Surgery

Background: The incidence rate of bile duct injury has not been changed for many years for both open or laparoscopic technique.  Open cholecystectomy has risen from 0.5% to 1.4% when gallbladder removal is performed laparoscopically.  Injuries of the bile duct system after laparoscopic cholecystectomy are more complex than that after an open approach, causing significant morbidity and even death.  From initial classification published by Bismuth, there have been many classifications of common bile duct injury.  We would reported the 30 days mortality rate following reconstruction after bile duct injury according to type of Bismuth classification. Case Report: 7 cases of common bile duct injury were reported from 2016 until 2018 following cholecystectomy (both open and laparoscopic), all cases were diagnosed as early complication and without intra operative cholangiography performed.  The most common bile duct injury was Bismuth type II and IV (2 patients in each type).  Reconstruction has been done by hepatico jejunostomy for type III and IV.  Choledoco Duodenostomy bypass was done for type I and II.  2 patients with bismuth type IV have long standing cholangitis and cannot survive during 30 days of follow up.  4 others patients could survive with no intra abdominal complication nor other morbidity. Conclusion:  Bismuth  classification was the simpliest type to described the bile duct injury, Bismuth type IV was associated with the high risk of 30 days mortality rate.   Keywords: bismuth classification, bile duct injury, cholecystectomy, mortality

Organic Dots with Large π-Conjugated Planar for Cholangiography beyond 1500 nm in Rabbits: A Non-Radioactive Strategy

Iatrogenic extrahepatic bile duct injury remains a dreaded complication while performing cholecystectomy. Although X-ray based cholangiography could reduce the incidence of biliary tract injuries, the deficiencies including radiation damage and expertise dependence hamper its further clinical application. The effective strategy for intraoperative cholangiography is still urgently required. Herein, a fluorescence-based imaging approach for cholangiography in the near-infrared IIb window (1500-1700 nm) using TT3-oCB, a bright aggregation-induced emission luminogen with large π-conjugated planar unit, is reported. In phantom studies, TT3-oCB nanoparticles exhibit high near-infrared IIb emission and show better image clarity at varying penetrating depths. When intrabiliary injected into the gallbladder or the common bile duct of the rabbit, TT3-oCB nanoparticles enable the real-time imaging of the biliary structure with deep penetrating capability and high signal-to-background ratio. Moreover, the tiny iatrogenic biliary injuries and the gallstones in established disease models could be precisely diagnosed by TT3-oCB nanoparticle assisted near-infrared IIb imaging. In summary, we reported a feasible application for aggregation-induced emission dots as biliary contrast agent and realized high-quality cholangiography in the near-infrared IIb window with precise diagnostic ability and nonradioactive damage, which could possibly be applied for intraoperative diagnosis.

Indocyanine green administration a day before surgery may increase bile duct detectability on fluorescence cholangiography during laparoscopic cholecystectomy

BACKGROUND

The optimal indocyanine green (ICG) administration protocol for fluorescence cholangiography during laparoscopic cholecystectomy (LC) has yet to be determined.

METHODS

A prospective study including 20 cases of ICG fluorescence-navigated LC was conducted. Accordingly, the first 10 patients were administered 2.5 mg of ICG on the day of surgery after intubation (surgery-day group), while the remaining 10 consecutive patients were administered 0.25 mg/kg of ICG on the evening before surgery (one-day-before group). Fluorescence intensity (FI) of each tissue and FI ratios were then compared between both groups.

RESULTS

The median interval between observation and ICG administration was 27 minutes and 16 hours 24 minutes in the surgery-day and one-day-before group, respectively. Although FI values for the common bile duct (CBD), liver, and hepatoduodenal ligament (HDL) were significantly lower in the one-day-before group than in the surgery-day group, CBD- , 0.6-1.2 vs 2.5, 0.9 = -4.8; P < .001), and CBD-HDL contrast (1.7, 1.4-2.4 vs 2.3, 1.5-13.3; P = .038) were significantly higher in the one-day-before group than in the surgery-day group.

CONCLUSION

ICG administration a day before LC may offer better CBD background contrast compared to administration just prior to surgery.

Fluorescence-guided hepatobiliary surgery with long and short wavelength fluorophores

Importance

Fluorescence-guided surgery (FGS) is a potentially powerful tool for hepatobiliary (HPB) surgery. The high sensitivity of fluorescence navigation is especially useful in settings where tactile feedback is limited.

Objective

The present narrative review evaluates literature on the use of FDA-approved fluorophores such as methylene blue (MB), 5-aminolevulinic acid (5-ALA), and indocyanine green (ICG) for clinical intra-operative image-guidance during HPB surgery.

Evidence Review

Approaches such as dosing, timing, imaging devices and comparative endpoints are summarized. The feasibility and safety of fluorophores in visualizing the biliary tree, identify biliary leaks, outline anatomic hepatic segments, identify tumors, and evaluate perfusion and graft function in liver transplants are discussed.

Findings

Tumor-specific probes are a promising advancement in FGS with a greater degree of specificity. The current status of tumor-specific probes being evaluated in clinical trials are summarized.

Conclusions and Relevance for Reviews

Relevant discussion of promising tumor-specific probes in pre-clinical development are discussed. Fluorescence-guidance in HPB surgery is relatively new, but current literature shows that the dyes are reliably able to outline desired structures with a variety of dosing, timing, and imaging devices to provide real-time intra-operative anatomic information to surgeons. Development of tumor-specific probes will further advance the field of HPB surgery especially during oncologic resections.

Preoperative endoscopic marking of the gastrointestinal tract using fluorescence imaging: submucosal indocyanine green tattooing versus a novel fluorescent over-the-scope clip in a survival experimental study

BACKGROUND

Intraoperative localization of endoluminal lesions is can be difficult during laparoscopy. Preoperative endoscopic marking is therefore necessary. Current methods include submucosal tattooing using visible dyes, which in case of transmural injection can impair surgical dissection. Tattooing using indocyanine green (ICG) coupled to intraoperative near-infrared (NIR) laparoscopy has been described. ICG is only visible under NIR-light, therefore, it doesn't impair the surgical workflow under white light even if there is spillage. However, ICG tattoos have rapid diffusion and short longevity. We propose fluorescent over-the-scope clips (FOSC), using a novel biocompatible fluorescent paint, as durable lesion marking.

METHODS

In six pigs, gastric and colonic endoscopic tattoos using 0.05 mg/mL of ICG and markings using the fluorescent OSC were performed (T0). Simultaneously, NIR laparoscopy was executed. Follow-up laparoscopies were conducted at postoperative day (POD) 4-6 (T1) and POD 11-12 (T2). During laparoscopy, fluorescence intensity was assessed. In one human cadaver, FOSC was used to mark a site on the stomach and on the sigmoid colon, respectively. Intraoperative detection during NIR laparoscopy was assessed.

RESULTS

Gastric and colonic ICG tattooing and OSC markings were easily visible using NIR laparoscopy on T0. All FOSC were visible at T1 and T2 in both stomach and colon, whereas the ICG tattooing at T1 was only visible in the stomach of 2 animals and in the colon of 3 animals. At T2, tattoos were not visible in any animal. FOSC were still visible in both stomach and colon of the human cadaver at 10 days.

CONCLUSION

Endoscopic marking using FOSC can be an efficient and durable alternative to standard methods.

The “critical view of safety (CVS)” cannot be applied—What to do? Strategies to avoid bile duct injuries

Laparoscopic cholecystectomy has become the standard procedure worldwide since the early 1990s for those patients whose gallbladder has to be removed as part of their underlying disease (NIH Consensus Statement 1992). The most common complication is iatrogenic bile duct injury, which has not improved significantly since the introduction of open laparoscopic cholecystectomy as compared with open cholecystectomy. The intraoperative injuries are mostly the result of a misinterpretation of anatomical structures due to severe inflammation or topographical variations. In order to minimize this risk, a number of improved operative techniques and behavioral measures have been formulated. Here, we present methodological and operative possibilities as well as techniques that in unclear situations can help to minimize the risk of intraoperative injuries of the biliary tract and the accompanying vascular system.

Assessment of intraoperative use of indocyanine green fluorescence imaging on the incidence of anastomotic leakage after rectal cancer surgery: a PRISMA-compliant systematic review and meta-analysis

BACKGROUND

The current data on the intraoperative use of indocyanine green (ICG) fluorescence imaging to reduce the anastomotic leak (AL) rate in rectal cancer surgery remain controversial. The aim of this systematic review and meta-analysis was to evaluate the efficacy of ICG fluorescence imaging in decreasing the AL rate after rectal cancer surgery.

METHODS

Studies comparing ICG fluorescence imaging with standard care in patients with rectal cancer were systematically searched from PubMed, Embase, Web of Science and Cochrane Library through January 2020. The current meta-analysis was performed according to the preferred reporting items for systematic review and meta-analysis guidelines. A pooled analysis was performed for the available data regarding the baseline features, AL rate and other surgical outcomes. RevMan version 5.3 software was used for the present meta-analysis.

RESULTS

Nine studies with a total of 2088 patients with rectal cancer (926 in the ICG group and 1162 in the control group) were included in the present study. In the pooled analysis, the available patient and tumour-related baseline data were all comparable and without significant heterogeneity. In the present pooled analysis, the AL rate in the ICG group was significantly lower (OR 0.34; 95% CI 0.22-0.52; p < 0.0001) than that in the control group. Additionally, intraoperative use of ICG was associated with a decreased overall complication rate (OR 0.57; 95% CI 0.42-0.78; p = 0.0003) and reduced reoperation rate (OR 0.26; 95% CI 0.08-0.86; p = 0.03) in patients who had rectal cancer surgery.

CONCLUSIONS

The present study demonstrated the superiority of the intraoperative use of ICG in reducing the AL rate. However, considering the limitations of the included studies, more high-quality prospective studies and randomized controlled trials are needed.

Fluorescence-based cholangiography: preliminary results from the IHU-IRCAD-EAES EURO-FIGS registry

INTRODUCTION

Near-infrared fluorescence cholangiography (NIRF-C) is a popular application of fluorescence image-guided surgery (FIGS). NIRF-C requires near-infrared optimized laparoscopes and the injection of a fluorophore, most frequently Indocyanine Green (ICG), to highlight the biliary anatomy. It is investigated as a tool to increase safety during cholecystectomy. The European registry on FIGS (EURO-FIGS: www.euro-figs.eu ) aims to obtain a snapshot of the current practices of FIGS across Europe. Data on NIRF-C are presented.

METHODS

EURO-FIGS is a secured online database which collects anonymized data on surgical procedures performed using FIGS. Data collected for NIRF-C include gender, age, Body Mass Index (BMI), pathology, NIR device, ICG dose, ICG timing of administration before intraoperative visualization, visualization (Y/N) of biliary structures such as the cystic duct (CD), the common bile duct (CBD), the CD-CBD junction, the common hepatic duct (CHD), Visualization scores, adverse reactions to ICG, operative time, and surgical complications.

RESULTS

Fifteen surgeons (12 European surgical centers) uploaded 314 cases of NIRF-C during cholecystectomy (cholelithiasis n = 249, cholecystitis n = 58, polyps n = 7), using 4 different NIR devices. ICG doses (mg/kg) varied largely (mean 0.28 ± 0.17, median 0.3, range: 0.02-0.62). Similarly, injection-to-visualization timing (minutes) varied largely (mean 217 ± 357; median 57), ranging from 1 min (direct intragallbladder injection in 2 cases) to 3120 min (n = 2 cases). Visualization scores before dissection were significantly correlated, at univariate analysis, with ICG timing (all structures), ICG dose (CD-CBD), device (CD and CD-CBD), surgeon (CD and CD-CBD), and pathology (CD and CD-CBD). BMI was not correlated. At multivariate analysis, pathology and timing remained significant factors affecting the visualization scores of all three structures, whereas ICG dose remained correlated with HD visualization only.

CONCLUSIONS

The EURO-FIGS registry has confirmed a wide disparity in ICG dose and timing in NIRF-C. EURO-FIGS can represent a valuable tool to promote and monitor FIGS-related educational and consensus activities in Europe.

Laparoscopic cholecystectomy for cholecystitis using direct gallbladder indocyanine green injection fluorescence cholangiography: A case report

Laparoscopic cholecystectomy is the treatment of choice for almost all biliary diseases. We present a novel technique using near-infrared fluorescence imaging for laparoscopic cholecystectomy.

A 78-year-old woman diagnosed with acute cholecystitis (Grade II) was scheduled for emergency laparoscopy according to Tokyo Guidelines 2018. We performed a direct percutaneous drainage of the gallbladder to grasp the gallbladder itself. Subsequently, indocyanine green was administered into the gallbladder through the same tube, and the cystic and common bile ducts could be easily detected. The postoperative course was good, and the patient was discharged in remission nine days after the surgery.

Real-time fluorescence cholangiography with indocyanine green is reliable for biliary anatomy visualization before the dissection of the Calot's triangle. Our method of indocyanine green injection into the same drainage catheter does not require pre-preparation and can be simultaneously performed with drainage intraoperatively. This surgical technique is simple, straightforward, and effective and can be useful in intraoperative decision-making, especially during laparoscopic cholecystectomy.

Evolution of photodynamic medicine based on fluorescence image-guided diagnosis using indocyanine green and 5-aminolevulinic acid

New diagnostic techniques based on photodynamic medicine, such as near-infrared fluorescence using indocyanine green (NIR-ICG) and 5-aminolevulinic acid-mediated photodynamic diagnosis (ALA-PDD), are aiding navigation tasks across various fields of surgery. Specifically, NIR-ICG is being used for the intraoperative identification of sentinel lymph nodes or blood vessels in organ resection and for blood flow evaluation in surgery. These ICG-fluorescent imaging techniques could provide an additional and potentially valuable way to identify vascular and lymphatic structures in surrounding tissue. 5-Aminolevulinic acid is a precursor of a photosensitizing substance with affinity for tumors; thus, diagnostic laparoscopy using ALA-PDD in combination should improve the accuracy of detecting peritoneal dissemination in patients with advanced gastric cancer. The ability to overlay fluorescent imaging with conventional color images in real time using ALA-PDD and NIR with ICG would be of immense benefit to surgeons, providing good visualization and detection of target lesions not seen with the naked eye. A multi-center clinical study examining the safety and efficacy of ALA-PDD during laparoscopic examination for patients with advanced gastric cancer is currently underway in the form of doctor-initiated trials, and further verification studies will be conducted. Such imaging capability could have broad potential across cancer and vascular surgery.

A patient with cystic duct remnant calculus treated by laparoscopic surgery combined with near-infrared fluorescence cholangiography

BACKGROUND

The recurrence of symptoms present before cholecystectomy may be caused by a cystic duct remnant. The resolution of cystic duct remnant syndrome may require surgical resection, but identification of the duct remnant during laparoscopic surgery may be difficult because of adhesions following the previous procedure. Open surgery, which is more invasive than laparoscopic surgery, is frequently chosen to avoid bile duct injury.

CASE PRESENTATION

The patient was a 24-year-old woman with previous laparoscopic cholecystectomy for chronic cholecystitis and repeated attacks of biliary colic. The postoperative course was uneventful, but computed tomography revealed a remnant cystic duct calculus. Ten months after surgery, the patient returned to our department for right hypochondriac pain. Laparoscopic remnant cystic duct resection was performed with intraoperative near-infrared (NIR) fluorescence cholangiography to visualize the common bile duct and remnant cystic duct. The postoperative course was uneventful and the patient was discharged on day 3 after surgery. At the 6-month follow-up, she had no recurrence of pain.

CONCLUSION

Laparoscopic surgery with NIR cholangiography is a safe and effective alternative for the removal of a cystic duct remnant calculus after cholecystectomy.

Fluorescence cholangiography enhances surgical residents’ biliary delineation skill for laparoscopic cholecystectomies

BACKGROUND

Laparoscopic cholecystectomy (LC) is a minimally invasive procedure, often performed by surgical residents (SRs). Fluorescence cholangiography (FC) enables real-time identification of biliary anatomy.

AIM

To investigate the benefit of FC for enhancing SRs’ identification skills.

METHODS

Prospective data was collected from January 2018 to June 2018 at our hospital. The study cohorts were the SRs (study group, n = 15) and the surgical staff (SS; control group, n = 9). Participants were assigned to watch videos of LCs with FC from five different patients who had gallbladder disease, and identify structures in the video clips (including cystic duct, common bile duct, common hepatic duct, and cystic artery), first without FC, and then with FC.

RESULTS

In the without-FC phase, the overall misidentification rate by SRs (21.7%) was greater than that of the SS (11.8%; P = 0.018), However, in the FC phase, the two groups did not significantly differ in misidentification rates (23.3% vs 23.3%, P = 0.99). Paired-structure analysis of the without-FC and with-FC phases for the SR group found a significantly higher misidentification rate in the without-FC phase than the with-FC phase (21.9% vs 10.9%; P < 0.01). However, misidentification rates in the with-FC phase did not significantly differ between SRs and SS.

CONCLUSION

FC enhanced identification skills of inexperienced surgeons during LC compared with conventional training. Combined with simulation-based video training, FC is a promising tool for enhancing technical and decision skills of trainees and inexperienced surgeons.

[Indocyanine green fluorescence to visualize the ureteric vascularization of kidney transplants: An exploratory study]

INTRODUCTION

Urinary complications after kidney transplantation are common and can compromise renal function. While they are mainly attributed to ischemic lesions of the ureter, there is no existing method to evaluate its vascularization during surgery. The aim of the study was to evaluate if indocyanine green, revealed by infra-red light andused to visualize tissue perfusion, could provide an appreciation of the ureter's vascularization during kidney transplantation.

METHODS

This feasibility study was conducted over one month, on eleven consecutive kidney transplants. During transplantation, an injection of indocyanine green enabled the surgeon to visualize in real time with an infra-red camera the ureter fluorescence. Its intensity was reported on a qualitative and semi-quantitative scale. Occurrence of urinary complications such as stenosis or ureteral fistula were collected during 6 months.

RESULTS

In all of the 11 cases (100%), the last centimeters of the ureters were not fluorescent. Three (27%) ureters were poorly or partiallly fluorescent. Out of these three cases, only one case of urinary fistula occurred, followed by ureteric stenosis. In the series, two fistulas (18%) and two ureteric stenoses (18%) occurred. No side effects were observed. The low number of events did not allow statistical analysis.

CONCLUSION

Infra-red fluorescence of indocyanine green could be a simple and innovative way to appreciate the transplant's ureteric vascularization during kidney transplantation. It could help surgeons to identify the level of ureter section and to decide the anastomosis technique, in order to limit urinary complications.

LEVEL OF EVIDENCE

3.

Extrahepatic cholangiography in near-infrared II window with the clinically approved fluorescence agent indocyanine green: a promising imaging technology for intraoperative diagnosis

Rationale: Biliary tract injury remains the most dreaded complication during laparoscopic cholecystectomy. New intraoperative guidance technologies, including near-infrared (NIR) fluorescence cholangiography with indocyanine green (ICG), are under comprehensive evaluation. Previous studies had shown the limitations of traditional NIR light (NIR-I, 700-900 nm) in visualizing the biliary tract structures in specific clinical situations. The aim of this study was to evaluate the feasibility of performing the extrahepatic cholangiography in the second NIR window (NIR-II, 900-1700 nm) and compare it to the conventional NIR-I imaging. Methods: The absorption and emission spectra, as well as fluorescence intensity and photostability of ICG-bile solution in the NIR-II window were recorded and measured. In vitro intralipid® phantom imaging was performed to evaluate tissue penetrating depth in NIR-I and NIR-II window. Different clinical scenarios were modeled by broadening the penetration distance or generating bile duct injuries, and bile duct visualization and lesion site diagnosis in the NIR-II window were evaluated and compared with NIR-I imaging. Results: The fluorescence spectrum of ICG-bile solution extends well into the NIR-II region, exhibiting intense emission value and excellent photostability sufficient for NIR-II biliary tract imaging. Extrahepatic cholangiography using ICG in the NIR-II window obviously reduced background signal and enhanced penetration depth, providing more structural information and improved visualization of the bile duct or lesion location in simulated clinical scenarios, outperforming the NIR-I window imaging. Conclusions: The conventional clinically approved agent ICG is an excellent fluorophore for NIR-II bile duct imaging. Fluorescence cholangiography with ICG in the NIR-II window could provide adequate visualization of the biliary tract structures with increased resolution and penetration depth and might be a valid option to increase the safety of cholecystectomy in difficult cases.

Fluorescence or X-ray cholangiography in elective laparoscopic cholecystectomy: a randomized clinical trial

BACKGROUND

Safe laparoscopic cholecystectomy may necessitate biliary imaging, and non-invasive fluorescence cholangiography may have advantages over contrast X-ray cholangiography. This trial compared fluorescence and X-ray cholangiography for visualization of the critical junction between the cystic, common hepatic and common bile ducts.

METHODS

This non-inferiority blinded RCT included patients who had either intraoperative fluorescence cholangiography using 0·05 mg/kg indocyanine green or X-ray cholangiography during elective laparoscopic cholecystectomy.

RESULTS

Between March 2015 and August 2018, a total of 120 patients were randomized (60 in each group). There were no drop-outs and 30-day follow-up data were available for all patients. In intention-to-treat analysis, there was no difference between the fluorescence and X-ray cholangiography groups in ability to visualize the critical junction (49 of 60 versus 51 of 60 respectively; P = 0·230). Fluorescence cholangiography was faster by a few minutes: median 2·0 (range 0·5-5·0) versus 4·8 (1·3-17·6) min (P < 0·001).

CONCLUSION

Fluorescence cholangiography was confirmed to be non-inferior to X-ray cholangiography in visualizing the critical junction during laparoscopic cholecystectomy. Registration number: NCT02344654 ( http://www.clinicaltrials.gov).

Fluorescence-Guided Surgery for Hepatoblastoma with Indocyanine Green

Fluorescence-guided surgery with indocyanine green (ICG) for malignant hepatic tumors has been gaining more attention with technical advancements. Since hepatoblastomas (HBs) possess similar features to hepatocellular carcinoma, fluorescence-guided surgery can be used for HBs, as aggressive surgical resection, even for distant metastases of HBs, often contributes positively to R0 (complete) resection and subsequent patient survival. Despite a few caveats, fluorescence-guided surgery allows for the more sensitive identification of lesions that may go undetected by conventional imaging or be invisible macroscopically. This leads to precise resection of distant metastatic tumors as well as primary liver tumors.

Technical Note: Are Currently Used Measurements of Fluorescence Intensity in Near Infrared Fluorescence Imaging During Laparoscopic Cholecystectomy Comparable?

Aims: To investigate whether different calculation methods to express fluorescence intensity (FI) as target-to-background (BG) ratio are comparable and which method(s) match with human perception. Materials and Methods: Comparison of three calculation methods from current literature (OsiriX^®, ImageJ^®, and Photoshop^®) to objectify FI during laparoscopic cholecystectomy measured at the exact same locations within recorded images of two categories: ex vivo and in vivo. Currently applied formulas to present FI in relation to the BG signal are compared with the subjective assessment by the human observers. These three formulas are Signal contrast = (FI in fluorescence regions-FI in BG)/255; Target-to-background ratio = (FI of target-FI of BG)/FI of BG; Signal-to-background ratio = FI of cystic duct/FI of liver and Target-to-background ratio = (FI of target-noise)/(FI of BG-noise). Results: In our evaluation OsiriX and ImageJ provided similar results, whereas OsiriX values were structurally slightly lower compared with ImageJ. Values obtained through Photoshop were less evidently related to those obtained with OsiriX and ImageJ. The formula Target-to-background ratio = (FI of target-noise)/(FI of BG-noise) was less corresponding with human perception compared with the other used formulas. Conclusions: FI results based on measurements using the programs OsiriX and ImageJ are similar, allowing for comparison of results between these programs. Results using Photoshop differ significantly, making direct comparison impossible. This is an important finding when interpreting study results. We propose to report both target and BG FI in articles, so that proper interpretation between articles can be made.

Near-infrared fluorescence laparoscopy of the ureter with three preclinical dyes in a pig model

Background

Ureteric injury is reported to occur in 1–7.6% of colorectal surgeries. To reduce the incidence of ureteral injury, it is essential to identify the ureters. The use of near-infrared fluorescence (NIRF) imaging with intravenously administered dyes might be of added value for ureteral visualization during laparoscopy. The aim of this study is to assess the performance of three preclinical dyes; IRDye^® 800BK, IRDye^® 800NOS and IRDye^® 800CW, for near-infrared fluorescence laparoscopy of the ureter in pigs.

Methods

In three female Dutch landrace pigs, the new dyes were evaluated. In each pig, 1 dye was tested using a 6-mg intravenous dose in a concentration of 1 mg/ml. Imaging was performed in fluorescence mode and white light mode with a laparoscopic imaging system. In order to further evaluate the dyes, an ex vivo imaging experiment was performed, in which 8 decreasing concentrations per dye, diluted in PBS, were evaluated in a transparent test tube with NIRF mode at a distance of 1, 5 and 10 cm from the laparoscope.

Results

All three dyes were effective in allowing the identification of the ureter with NIRF imaging. The ureter became fluorescent after 35, 45 and 10 min, respectively, for IRDye^® 800BK, IRDye^® 800NOS and IRDye^® 800CW with a maximum target-to-background ratio (TBR) of 2.14, 0.66 and 1.44, respectively. In the ex vivo imaging experiment, all three dyes produced a strong fluorescence signal at all concentrations and all distances evaluated.

Conclusions

Intravenous administration of the preclinical dyes IRDye^® 800CW, IRDye^® 800 BK and IRDye^® 800NOS facilitated successful identification of the anatomical course of the ureter in living pig models. The highest measured TBR occurred with the use of IRDye^® 800BK. Ex vivo, a correlation was observed between the fluorescence intensities of the signal with the concentration of the dye and with the distance to the object.

Safe laparoscopic cholecystectomy: A systematic review of bile duct injury prevention

BACKGROUND

Since the introduction of laparoscopic cholecystectomy (LC), a substantial increase in bile duct injury (BDI) incidence was noted. Multiple methods to prevent this complication have been developed and investigated. The most suitable method however is subject to debate. In this systematic review, the different modalities to aid in the safe performance of LC and prevent BDI are delineated.

MATERIALS AND METHODS

A systematic search for articles describing methods for the prevention of BDI in LC was conducted using EMBASE, Medline, Web of science, Cochrane CENTRAL and Google scholar databases from inception to 11 June 2018.

RESULTS

90 studies were included in this systematic review. Overall, BDI preventive techniques can be categorized as dedicated surgical approaches (Critical View of Safety (CVS), fundus first, partial laparoscopic cholecystectomy), supporting imaging techniques (intraoperative radiologic cholangiography, intraoperative ultrasonography, fluorescence imaging) and others. Dedicated surgical approaches demonstrate promising results, yet limited research is provided. Intraoperative radiologic cholangiography and ultrasonography demonstrate beneficial effects in BDI prevention, however the available evidence is low. Fluorescence imaging is in its infancy, yet this technique is demonstrated to be feasible and larger trials are in preparation.

CONCLUSION

Given the low sample sizes and suboptimal study designs of the studies available, it is not possible to recommend a preferred method to prevent BDI. Surgeons should primarily focus on proper dissection techniques, of which CVS is most suitable. Additionally, recognition of hazardous circumstances and knowledge of alternative techniques is critical to complete surgery with minimal risk of injury to the patient.

Fluorescence Imaging for Minimally Invasive Cancer Surgery

This article demonstrates surgical techniques of intraoperative fluorescence imaging using indocyanine green, focusing on its application in minimally invasive hepatobiliary and pancreatic surgery. In this area, indocyanine green fluorescence imaging has been applied to liver cancer identification, fluorescence cholangiography, delineation of hepatic segments, and fluorescence angiography and perfusion assessment. The development of target-specific fluorophores and advances in imaging technology will allow real-time intraoperative fluorescence imaging to develop into an essential intraoperative navigation tool. This property may contribute to enhancing both accuracy and safety of minimally invasive surgery.

Laparoscopic cholecystectomy using the PINPOINT® Endoscopic Fluorescence Imaging System with intraoperative fluorescent imaging for acute cholecystitis: A case report

We report on a laparoscopic cholecystectomy (LC) for acute cholecystitis (AC) using the bright field/full-color fluorescence laparoscope system PINPOINT^® (Novadaq, Mississauga, ON, Canada).

The patient was an 85-year-old man who was diagnosed with moderate AC. Indocyanine green (ICG) was administered just before surgery, and we used only PINPOINT^® to perform the LC. The advantage of this procedure is that it can be performed while viewing ICG fluorescence in the cystic duct. Since the gallbladder is imaged with this technique, it is also advantageous from the perspective of deciding at which layer to detach the gallbladder from the liver. The operative time was 81 minutes, and blood loss was 5 ml. There were no perioperative complications, and the patient was discharged on post-operative day 6.

•

The PINPOINT system is safely and effectively at laparoscopic cholecystectomy.

•

We were able to identify a cystic duct with a common bile duct, and we completed the surgery without perioperative complications.

•

We concluded that PINPOINT^® might help avoid bile duct injury, which can be a serious complication when performing laparoscopic cholecystectomy for acute cholecystitis.

Laparoscopic cholecystectomy with aberrant bile duct detected by intraoperative fluorescent cholangiography concomitant with angiography: A case report

•

Usefulness and safety of combined vascular and biliary fluorescent ICG imaging during laparoscopic cholecystectomy was reported.

•

Aberrant bile ducts are rare anatomical variation and clinically important because of the susceptibility to injury during cholecystectomy.

•

We encountered a case of laparoscopic cholecystectomy with an aberrant bile duct detected by intraoperative fluorescent cholangiography concomitant with angiography.

Introduction

Laparoscopic cholecystectomy is the standard surgical treatment for patients with benign gallbladder disease. However, bile duct injury continues to be reported as a surgical complication. Intraoperative cholangiography is recommended to reduce the risk of bile duct injury during laparoscopic cholecystectomy. Intraoperative cholangiography using indocyanine green, which is excreted into bile and shows fluorescence under infrared light, has recently been reported as useful in preventing bile duct injury during laparoscopic cholecystectomy. We report here a case of laparoscopic cholecystectomy with an aberrant bile duct detected by intraoperative fluorescent cholangiography concomitant with angiography.

Presentation of case

An 82-year-old woman was diagnosed with cholecystolithiasis and underwent laparoscopic cholecystectomy. An aberrant bile duct branching from the right side of the common hepatic duct was detected by intraoperative indocyanine green fluorescent cholangiography. Furthermore, we were able to confirm the cystic artery by reinjecting indocyanine green during the procedure. Laparoscopic cholecystectomy was performed safely without injuring the aberrant bile duct, despite no recognition of the abnormality on preoperative computed tomography or magnetic resonance imaging.

Discussion and conclusions

Aberrant bile ducts are rare anatomical variation and clinically important because of the susceptibility to injury during cholecystectomy. Our case reported for the first time that fluorescence cholangiography concomitant with angiography was useful for identifying an aberrant bile duct and the cystic artery during laparoscopic cholecystectomy.

Evaluation of a novel dye for near-infrared fluorescence delineation of the ureters during laparoscopy

BACKGROUND

Iatrogenic ureteric injury remains a risk in laparoscopic pelvic procedures. Near-infrared fluorescence (NIRF) imaging is a promising new technique for enhanced intraoperative visualization of anatomical structures that could improve the safety of laparoscopic surgery. A new dye, IRDye® 800-BK, has been developed for intraoperative visualization of the ureters using NIRF. The present study was a first evaluation of the performance of IRDye® 800-BK for ureteric imaging during NIRF laparoscopy.

METHODS

This study consisted of three parts: real-time in vivo NIRF imaging using IRDye® 800-BK in pigs during laparoscopic surgery, ex vivo NIRF imaging of freshly explanted pig ureters and ex vivo NIRF imaging of explanted human ureters.

RESULTS

In all animals, both left and right ureters were visualized throughout the laparoscopic procedure for 120 min, with the best results at a dose of 0·15 mg dye per kg bodyweight. NIRF imaging was successful in all human and porcine ureters studied, with a range of dye concentrations.

CONCLUSION

NIRF imaging of the ureters using IRDye® 800-BK was used successfully both in vivo in a porcine model, and ex vivo in porcine and human ureters.

Optimal timing of preoperative indocyanine green administration for fluorescent cholangiography during laparoscopic cholecystectomy using the PINPOINT® Endoscopic Fluorescence Imaging System

INTRODUCTION

The PINPOINT® Endoscopic Fluorescence Imaging System (Novadaq, Mississauga, Canada) allows surgeons to visualize the bile ducts during laparoscopic cholecystectomy. Surgeons can continue operation while confirming the bile ducts' fluorescence with a bright-field/color image. However, strong fluorescence of the liver can interfere with the surgery. Here, we investigated the optimal timing of indocyanine green administration to allow fluorescent cholangiography to be performed without interference from the liver fluorescence.

METHODS

A total of 72 patients who underwent laparoscopic cholecystectomy were included in this study. The timing of indocyanine green administration was set immediately before surgery and at 3, 6, 9, 12, 15, 18, and 24 h before surgery. The luminance intensity ratios of gallbladder/liver, cystic duct/liver, and common bile duct/liver were measured using the ImageJ software (National Institutes of Health, Bethesda, USA). Visibility of the gallbladder and bile ducts was classified into three categories (grades A, B, and C) based on the degree of visibility in contrast to the liver.

RESULTS

The luminance intensity ratio for the gallbladder/liver, cystic duct/liver, and common bile duct/liver was ≥1 in the 15-, 18-, and 24-h groups. The proportion of cases in which evaluators classified the visibility of the gallbladder and bile ducts as grade A (best visibility) reached a peak in the 15-h group and decreased thereafter.

CONCLUSIONS

In the present study, the optimal timing of indocyanine green administration for fluorescent cholangiography during laparoscopic cholecystectomy using the PINPOINT Endoscopic Fluorescence Imaging System was 15 h before surgery.

Evaluation of laparoscopic cholecystectomy using indocyanine green cholangiography including cholecystitis: A retrospective study

Intraoperative cholangiography involving the excretion of fluorescent indocyanine green (ICG) into the bile is used to determine biliary anatomy in laparoscopic cholecystectomy (LC). This study aimed to evaluate the features of intraoperative ICG cholangiography, in LC with cholecystitis, and compared the delineation of the cystic duct (CD) between ICG cholangiography and magnetic resonance cholangiopancreatography (MRCP).Participants comprised 65 patients undergoing LC using ICG cholangiography.Fifty-eight patients (89.2%) were diagnosed with gallbladder stones and 32 (49.2%) with acute cholecystitis. ICG cholangiography identified CD in 54 patients (83.1%) and did not identify CD in 11 patients (16.9%). The mean value of the fluorescence intensity in the identified CD group by ICG cholangiography was 87.6 ± 31.5 arbitrary unit and that in the not identified CD group by ICG cholangiography was 24.4 ± 10.1 arbitrary unit (P < .001). Compared with the patients in the identified CD group, those in the not identified CD group had higher incidence of acute cholecystitis (P < .001), and higher conversion rates (P = .003). A correlation between the delineation of CD by ICG cholangiography and MRCP was analyzed, and it revealed a correlation between each other (P = .002)Inflammation had harmful effects with regard to the passing of CD. If we can identify CD or common bile duct with ICG cholangiography, we may be able to perform LC with confidence, even in the presence of severe inflammation.

A practical guide for the use of indocyanine green and methylene blue in fluorescence-guided abdominal surgery

Near-infrared (NIR) fluorescence imaging is gaining clinical acceptance over the last years and has been used for detection of lymph nodes, several tumor types, vital structures and tissue perfusion. This review focuses on NIR fluorescence imaging with indocyanine green and methylene blue for different clinical applications in abdominal surgery with an emphasis on oncology, based on a systematic literature search. Furthermore, practical information on doses, injection times, and intraoperative use are provided.