Fluorescent cholangiography illuminating the biliary tree during laparoscopic cholecystectomy

Real-time navigation during hepatectomy using fusion indocyanine green-fluorescence imaging: protocol for a prospective cohort study

INTRODUCTION

In-vivo fluorescence imaging techniques using indocyanine green (ICG) to identify liver tumours and hepatic segment boundaries have been recently developed. The purpose of this study is to evaluate the efficacy of fusion ICG-fluorescence imaging for navigation during hepatectomy.

METHODS AND ANALYSIS

This will be an exploratory single-arm clinical trial; patients with liver tumours will undergo hepatectomy using the ICG-fluorescence imaging system. In total, 110 patients with liver tumours scheduled for elective hepatectomy will be included in this study. Preoperatively, ICG will be intravenously injected at a dose of 0.5 mg/kg body weight within 2 days. To detect liver tumours intraoperatively, the hepatic surface will be initially observed using the ICG-fluorescence imaging system. After identifying and clamping the portal pedicle corresponding to the hepatic segments, including the liver tumours to be resected, additional ICG will be injected intravenously at a dose of 0.5 mg/kg body weight to identify the boundaries of the hepatic segments. The primary outcome measure will be the success or failure of the ICG-fluorescence imaging system in identifying hepatic segments. The secondary outcomes will be the success or failure in identifying liver tumours, liver function indicators, operative time, blood loss, rate of postoperative complications and recurrence-free survival. The findings obtained through this study are expected to help to establish the utility of ICG-fluorescence imaging systems, and therefore contribute to prognostic outcome improvements in patients undergoing hepatectomy for various causes.

ETHICS AND DISSEMINATION

The protocol has been approved by the Kobe University Clinical Research Ethical Committee. The findings of this study will be disseminated widely through peer-reviewed publications and conference presentations.

TRIAL REGISTRATION NUMBER

UMIN000031054 and jRCT1051180070.

Real-time Navigation for Liver Surgery Using Projection Mapping With Indocyanine Green Fluorescence: Development of the Novel Medical Imaging Projection System

OBJECTIVE

The aim of the present study was to evaluate the usefulness of a new imaging device, the Medical Imaging Projection System (MIPS), which uses the indocyanine green emission signal and active projection mapping, for liver resection.

BACKGROUND

During anatomic liver resection, surgeons cannot completely view the intraparenchymal structure. Although a fluorescent imaging technique using indocyanine green has recently been developed for hepatobiliary surgery, limitations in its application for real-time navigation persist.

METHODS

We conducted a retrospective review of surgical and clinical outcomes for 23 patients who underwent anatomic hepatectomy using the MIPS and 29 patients who underwent the procedure without MIPS guidance, between September 2014 and September 2015.

RESULTS

Preoperative characteristics were comparable between the 2 groups. No significant between-group differences were identified with regard to surgical and clinical outcomes. The demarcation lines were clearly projected by the MIPS in 21 patients; however, the boundary line was undetectable in 2 patients.

CONCLUSIONS

We developed the MIPS to address limitations in current intraoperative imaging methods. Our retrospective analysis provides evidence of the feasibility and clinical utility of the MIPS to identify anatomical landmarks for parenchymal dissection. The MIPS holds promise as a novel real-time navigation system for liver resection.

Intraoperative detection of the remnant cystic duct during robot-assisted surgery using near-infrared fluorescence imaging: a case report

Background

Post cholecystectomy syndrome is characterized as recurrence of symptoms as experienced before cholecystectomy. In rare cases, a remnant cystic duct is causing these symptoms and occasionally surgical resection is performed. During surgery, visualization of the biliary ducts could be difficult due to inflammation and dense adhesions.

Case presentation

In this article, we presented a 36-year old woman with post-cholecystectomy syndrome in which we evaluated the feasibility of near-infrared (NIR) fluorescence imaging using indocyanine green (ICG) for visualization of the remnant cystic and common bile duct during robot-assisted surgery. Intraoperative visualization of the remnant biliary duct and other important structures was feasible, and resection of the remnant cystic duct was successfully performed under fluorescence guidance, without any complications.

Conclusions

NIR fluorescence imaging of the biliary ducts using ICG does not prolong the operating time, and could potentially decrease the operation time in difficult procedures, because of easy and fast detection of the biliary tract. Furthermore, it is a non-hazardous and non-invasive technique, as it does not require use of radiation and cannot cause bile duct injury. This case illustrated that ICG NIR fluorescence imaging during difficult robot-assisted surgical procedures of the bile ducts is effective and therefore highly recommended.

Electronic supplementary material

The online version of this article (10.1186/s12893-019-0567-8) contains supplementary material, which is available to authorized users.

Identification of aberrant subvesical bile duct by using intraoperative fluorescent cholangiography: A case report

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Aberrant subvesical bile duct poses risk of bile duct injury during cholecystectomy.

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Intraoperative fluorescent cholangiography (IFC) could allow us to identify a fine minute bile duct.

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IFC is one of a promising technique to improve the safety of cholecystectomy further.

Introduction

Aberrant subvesical bile ducts are rare structural anomaly located in the peri-hepatic gallbladder fossa. This duct poses the risk for intraoperative bile duct injury resulting in clinically relevant bile leakage.

Presentation of case

Aberrant subvesical bile duct was detected by preoperative magnetic resonance cholangiopancreatography in a 52-year old woman with gallbladder polypoid tumor harboring the risk to be gallbladder cancer. During open cholecystectomy with full thickness dissection, the aberrant duct was identified by intraoperative fluorescent cholangiography (IFC), and dissected safely.

Discussion

Aberrant subvesical bile ducts are mostly found unexpectedly as intra and/or postoperative bile leakage, and remain an important cause of bile duct injuries after laparoscopic cholecystectomy. IFC, which offers real-time imaging of biliary anatomy, has a potential to overcome these problems.

Conclusion

We performed cholecystectomy by using IFC to identify the aberrant subvesical bile duct. To the best of our knowledge, this is the first report showing the fluorescence image of an aberrant subvesical bile duct in a state of nature.

A zwitterionic near-infrared fluorophore for real-time ureter identification during laparoscopic abdominopelvic surgery

Iatrogenic injury of the ureters is a feared complication of abdominal surgery. Zwitterionic near-infrared fluorophores are molecules with geometrically-balanced, electrically-neutral surface charge, which leads to renal-exclusive clearance and ultralow non-specific background binding. Such molecules could solve the ureter mapping problem by providing real-time anatomic and functional imaging, even through intact peritoneum. Here we present the first-in-human experience of this chemical class, as well as the efficacy study in patients undergoing laparoscopic abdominopelvic surgery. The zwitterionic near-infrared fluorophore ZW800-1 is safe, has pharmacokinetic properties consistent with an ideal blood pool agent, and rapid elimination into urine after a single low-dose intravenous injection. Visualization of structure and function of the ureters starts within minutes after ZW800-1 injection and lasts several hours. Zwitterionic near-infrared fluorophores add value during laparoscopic abdominopelvic surgeries and could potentially decrease iatrogenic urethral injury. Moreover, ZW800-1 is engineered for one-step covalent conjugatability, creating possibilities for developing novel targeted ligands.

Iatrogenic injury of the ureters is a feared complication of laparoscopic abdominal surgery. Here the authors present the NIR fluorophore ZW800-1 as an intraoperative imaging agent for ureter mapping, showing its safety, pharmacokinetic properties, and efficacy in healthy volunteers and patients undergoing abdominopelvic surgery.

Routine near infra-red indocyanine green fluorescent cholangiography versus intraoperative cholangiography during laparoscopic cholecystectomy: a case-matched comparison

BACKGROUND

The aim is to evaluate safety and efficacy of near infra-red (NIR) indocyanine green (ICG) fluorescence structural imaging during laparoscopic cholecystectomy (LC) (Group A) and to compare perioperative data, including operative time, with a series of patients who underwent LC with routine traditional intraoperative cholangiography (IOC) (Group B).

METHODS

Forty-four patients with acute or chronic cholecystitis underwent NIR-ICG fluorescent cholangiography during LC. ICG was administered intravenously at different time intervals or by direct gallbladder injection during surgery. Fluorescence intensity and anatomy identification were scored according to a visual analogue scale between 1 (least accurate) and 5 (most accurate). Group B patients (n = 44) were chosen from a prospectively maintained database of patients who underwent LC with routine IOC, matched for age, sex, body mass index, and diagnosis with group A patients.

RESULTS

No adverse reactions were recorded. In group A, mean time between intravenous administration of ICG and surgery was 10.7 ± 8.2 (range 2-52) h. Administered doses ranged from 3.5 to 13.5 mg. Fluorescence was present in all cases, scoring ≥ 3 in 41 patients. Mean operative time was 86.9 ± 36.9 (30-180) min in group A and 117.9 ± 43.4 (40-220) min in group B (p = 0.0006). No conversion to open surgery nor bile duct injuries were observed in either group.

CONCLUSIONS

LC with NIR-ICG fluorescent cholangiography is safe and effective for early recognition of anatomical landmarks, reducing operative time as compared to LC with IOC, even when residents were the main operator. NIR-ICG fluorescent cholangiography was effective in patients with acute cholecystitis and in the obese. Data collection into large registries on the results of NIR-ICG fluorescent cholangiography during LC should be encouraged to establish whether this technique might set a new safety standard for LC.

Fluorescence techniques in adrenal surgery

This chapter describes the use of fluorescence via indocyanine green (ICG) in minimally invasive adrenal surgery (laparoscopic and robotic). ICG is a non-toxic dye that can aid identification of vascular structures and parenchymal tissue planes in real time. The primary utility of ICG fluorescence in adrenal surgery is to help delineate the margins of resection, to guide a more precise operation. In particular, for patients with bilateral adrenal disease or a heredity associated with high risk of recurrence (e.g., VHL, MEN2a) this may facilitate subtotal adrenal resection (e.g., cortical sparing adrenalectomy), obviating the incidence of iatrogenic adrenal insufficiency and its numerous sequelae including lifelong hormone supplementation, osteoporosis and risk of Addisonian crisis.

Impact of indocyanine green-fluorescence imaging on distal pancreatectomy with celiac axis resection combined with reconstruction of the left gastric artery

BACKGROUND

We previously reported the usefulness of distal pancreatectomy with celiac axis resection (DP-CAR) with left gastric artery (LGA) reconstruction to prevent ischemic gastropathy. To evaluate the reconstruction quality, we performed intraoperative angiography with indocyanine green (ICG)-fluorescence imaging.

METHODS

21 consecutive patients planned for DP-CAR with LGA reconstruction were enrolled in this prospective, exploratory single-arm study from 2014 to 2017. After LGA reconstruction, intraoperative angiography revealed continuous arterial flow passing through the anastomotic sites and gradually increasing tissue perfusion in the stomach.

RESULTS

Three patients were excluded. Among the remaining 18 patients, we obtained good flow in 11 patients and poor flow in 7 patients after initial LGA reconstruction. Among the seven patients with poor flow, five underwent LGA re-anastomosis, three recovered good flow. The incidence of grade B/C DGE was 14% (2/14) in the finally good flow group and 75% (3/4) in the poor flow group (p = 0.019). Ischemic gastropathy occurred in two patients (50%) in the poor flow group (p = 0.039), including one with a gastric perforation.

DISCUSSION

Our data show that intraoperative angiography with ICG-fluorescence imaging can evaluate the reconstruction quality, thus contributing to improvements in the short-term outcome of DP-CAR with LGA reconstruction.

Usability of Intraoperative Fluorescence Imaging with Indocyanine Green During Laparoscopic Cholecystectomy After Percutaneous Transhepatic Gallbladder Drainage

BACKGROUND

Patients with persistent symptoms of acute cholecystitis for >72 h who cannot undergo urgent laparoscopic cholecystectomy (LC) often undergo percutaneous transhepatic gallbladder drainage (PTGBD) and delayed LC. However, intraoperative near-infrared fluorescence with indocyanine green (ICG) has recently become available in various surgical settings. Therefore, we evaluated the usability of intraoperative fluorescence imaging with ICG for LC after PTGBD in patients with acute cholecystitis.

METHODS

The preoperative and postoperative clinical characteristics of patients who underwent LC after PTGBD were retrospectively analyzed.

RESULTS

In total, 130 patients were reviewed. Intraoperative ICG fluorescence imaging was used in 39 (30.0%) patients, and none developed adverse reactions. Patients with ICG fluorescence imaging had a significantly shorter operative time (129 ± 46 vs. 150 ± 56 min, p = 0.0455), markedly lower conversion rate (2.6% vs. 22.0%, p = 0.0017), and lower proportion of subtotal cholecystectomy (0.0% vs. 6.6%, p = 0.0359) than patients without ICG fluorescence imaging. Independent risk factors for conversion to laparotomy during LC after PTGBD were the performance of PTGBD after 48 h from onset (OR 3.52; 95% CI 1.11-12.21; p = 0.0322), an unremoved PTGBD tube on LC (4.48, 1.46-15.00, p = 0.0084), and surgery without ICG (8.00, 1.28-159.47, p = 0.0231).

CONCLUSION

Intraoperative ICG fluorescence imaging produced better surgical outcomes without any adverse reactions. Early performance of PTGBD and intraoperative ICG fluorescence imaging can reduce the surgical difficulties in LC after PTGBD for acute cholecystitis.

The role of indocyanine green fluoroscopy for intraoperative bile duct visualization during laparoscopic cholecystectomy: an observational cohort study in 70 patients

Background

Bile duct injury is the most feared complication during laparoscopic cholecystectomy. Real-time intraoperative imaging using indocyanine green (ICG) might reduce the risk of bile duct injury by improving visualization of the biliary tree during laparoscopic cholecystectomy. We compared the outcomes of laparoscopic cholecystectomy in patients with and without real-time ICG.

Methods

A retrospective analysis of the data of patients undergoing laparoscopic cholecystectomy with and without ICG in a referral centre for minimally invasive surgery was performed. We hypothesized that laparoscopic cholecystectomy with real-time ICG enables a better identification of the biliary tree and thus increases surgical safety. The outcomes of laparoscopic cholecystectomy with and without ICG were compared using the duration of surgery, the rate of bile duct injury, the rate of conversion, complications and the length of stay.

Results

Seventy patients including 29 with and 41 without ICG underwent laparoscopic cholecystectomy within the period of investigation. The median duration of surgery was 53.0 vs. 54.0 min while the median length of stay was 2.0 d in the group with and without ICG respectively. The rate of conversion was 2.4% in the group without ICG, while no conversion was performed in the group with ICG. NO bile duct injury occurred in both groups. These differences were not statistically significant.

Conclusion

Laparoscopic cholecystectomy with real-time indocyanine green fluorescence cholangiography enables a better visualization and identification of biliary tree and therefore should be considered as a means of increasing the safety of laparoscopic cholecystectomy.

Intraoperative ICG-based imaging of liver neoplasms: a simple yet powerful tool. Preliminary results

BACKGROUND

Detecting small nodules that are grossly unidentifiable remains a major challenge in liver resection for cancer. Novel developments in navigation surgery, especially indocyanine green (ICG)-based fluorescence imaging, are making a clear breakthrough in addressing this issue. ICG is almost routinely administered during the preoperative stage in hepatobiliary surgery. However, its full potential has yet to be realized, partly because there are no precise guidelines regarding the optimal dose or timing of ICG injections before liver surgery. The main goal of this study was to design an algorithm for the management of ICG injections to achieve optimal liver staining results.

METHODS

Twenty-seven consecutive, unselected patients undergoing liver resection for cancer were enrolled and underwent preoperative liver function assessment by the LiMON test. Extra ICG i.v. injections at different doses and timings were performed. In vivo intraoperative analysis of the stain detected by near-infrared fluorescence imaging of the liver and ex vivo analysis of each resected nodule was performed and compared to the pathological analysis.

RESULTS

(i) The success rate of ICG injections in terms of liver staining was 92.6%; (ii) in the absence of or with 7 or more days from a previous ICG injection, the best dose to inject before the operation was 0.2 mg/kg, and the best timing was between 24 and 48 h before the scheduled surgery; and (iii) the ICG fluorescence patterns observed in the tumors were total fluorescence staining (41% of the cases), partial fluorescence staining (15%), rim fluorescence staining surrounding the tumor (30%), and no staining (15%).

CONCLUSIONS

This study is a building block for the characterization of liver nodules and the search for additional surface lesions undetected by preoperative radiological work-up-a crucial task for the successful treatment of liver cancer at an early stage using a safe, minimally invasive, and inexpensive technique.

Fluorescence guided surgery in liver tumors: applications and advantages

The use of fluorescence-guided surgery for benign and malignant hepatobiliary (HPB) neoplasms has significantly increased and improved imaging methods creating new interesting perspectives. A major challenge in HPB surgery is performing radical resection with maximal preservation of the liver parenchyma and obtaining a low rate of complications. Despite the developments, visual inspection, palpation, and intraoperative ultrasound remain the most utilized tools during surgery today. In laparoscopic and robotic HPB surgery palpation is not possible. Fluorescence imaging enables identification of subcapsular liver tumors through accumulation of indocyanine green (ICG), after preoperative intravenous injection, in cancerous tissues of hepatocellular carcinoma and in noncancerous hepatic parenchyma, around intrahepatic cholangiocarcinoma and liver metastases, and it can also be used for visualizing extrahepatic bile duct anatomy and hepatic segmental borders, increasing the accuracy and the easiness of open and minimally invasive hepatectomy. (www.actabiomedica.it)

Intraarterial indocyanine green (ICG) fluorescence augmentation by marking embryonal resection areas in colorectal surgery: a feasibility study in a porcine model

Aim: In this pilot animal study we examined whether it is possible to visualize the embryonal resection layers by using intraarterial indocyanine green (ICG) staining when performing total mesorectal excision (TME) for carcinoma of the rectum. Material and methods: We injected ICG into the inferior mesenteric artery (AMI) of four swines to see whether the watershed area of the arterial supply zone can be sufficiently visualized by fluorescence imaging in order to mark the right dissection area along the fascia parietalis before and during resection. Results: We observed a fluorescence signal in all the supplied areas of AMI but not in other parts of the abdominal cavity or other organs. Additionally, the mesorectum also showed a sharp border between colored and non-colored tissue. Conclusion: In this study we present that resection borders may be determined before resection based on ICG-perfusion and we showed that intraoperative exclusive coloring of the rectum including the mesorectum is possible. Visualizing resection borders based on ICG-perfusion before settling the first cut may be a new approach in oncological surgery.

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

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

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

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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.

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.

Indocyanine green-based fluorescence imaging in visceral and hepatobiliary and pancreatic surgery: State of the art and future directions

In recent years, the use of fluorescence-guided surgery (FGS) to treat benign and malignant visceral, hepatobiliary and pancreatic neoplasms has significantly increased. FGS relies on the fluorescence signal emitted by injected substances (fluorophores) after being illuminated by ad hoc laser sources to help guide the surgical procedure and provide the surgeon with real-time visualization of the fluorescent structures of interest that would be otherwise invisible. This review surveys and discusses the most common and emerging clinical applications of indocyanine green (ICG)-based fluorescence in visceral, hepatobiliary and pancreatic surgery. The analysis, findings, and discussion presented here rely on the authors' significant experience with this technique in their medical institutions, an up-to-date review of the most relevant articles published on this topic between 2014 and 2018, and lengthy discussions with key opinion leaders in the field during recent conferences and congresses. For each application, the benefits and limitations of this technique, as well as applicable future directions, are described. The imaging of fluorescence emitted by ICG is a simple, fast, relatively inexpensive, and harmless tool with numerous different applications in surgery for both neoplasms and benign pathologies of the visceral and hepatobiliary systems. The ever-increasing availability of visual systems that can utilize this tool will transform some of these applications into the standard of care in the near future. Further studies are needed to evaluate the strengths and weaknesses of each application of ICG-based fluorescence imaging in abdominal 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.

Indocyanine-Green Fluorescence-GUIDED Liver Resection of Metastasis from Squamous Cell Carcinoma Invading the Biliary Tree

Background. The concept of fluorescence-guided navigation surgery based on indocyanine green (ICG) is a developing interest in many fields of surgical oncology. The technique seems to be promising also during hepatic resection. Case Presentation. We reported our experience of ICG-fluorescence-guided liver resection of metastasis located at VIII Couinaud's segment from colon squamous cell carcinoma of a 74-year-old male patient. Results. After laparotomy, the fluorescing tumour has been clearly identified on the liver surface. We have also identified that a large area of fluorescent parenchyma that gets from the peripheral of the lesion up to the portal pedicle such as the neoplasia would interest the right biliary tree in the form of neoplastic lymphangitis. This datum was not preoperatively known. Conclusion. Fluorescent imaging navigation liver resection could be a feasible and safe technique helpful in identifying additional characteristics of lesion. It could be a powerful tool but further studies are required.

Optimizing the image of fluorescence cholangiography using ICG: a systematic review and ex vivo experiments

Background

Though often only briefly described in the literature, there are clearly factors that have an influence on the fluorescence intensity, and thereby the usefulness of the technique. This article aims to provide an overview of the factors influencing the fluorescence intensity of fluorescence imaging with Indocyanine green, primarily focussed on NIRF guided cholangiography.

Methods

A systematic search was conducted to gain an overview of currently used methods in NIRF imaging in laparoscopic cholecystectomies. Relevant literature was searched to gain advice on what methods to use. Ex vivo experiments were performed to assess various factors that influence fluorescence intensity and whether the found clinical advices can be confirmed.

Results

ICG is currently the most widely applied fluorescent dye. Optimal ICG concentration lies between 0.00195 and 0.025 mg/ml, and this dose should be given as early as achievable—but maximum 24 h—before surgery. When holding the laparoscope closer and perpendicular to the dye, the signal is most intense. In patients with a higher BMI and/or cholecystitis, fluorescence intensity is lower, but NIRF seems to be more helpful. There are differences between various marketed fluorescence systems. Also, no uniform method to assess fluorescence intensity is available yet.

Conclusions

This study identified and discussed several factors that influence the signal of fluorescence cholangiography. These factors should be taken into account when using NIRF cholangiography. Also, surgeons should be aware of new dyes and clinical systems, in order to benefit most from the potential of NIRF imaging.

Electronic supplementary material

The online version of this article (10.1007/s00464-018-6233-x) contains supplementary material, which is available to authorized users.

Application of fluorescent cholangiography during single-incision laparoscopic cholecystectomy for cholecystitis with a right-sided round ligament: Preliminary experience

An 82-year-old woman was diagnosed with cholecystitis with a right-sided round ligament. We planned a single-incision laparoscopic cholecystectomy. Based on the findings of fluorescent cholangiography, the running course of the common bile duct was confirmed before dissection of Calot's triangle, and the confluence between the cystic duct and the common bile duct was exposed after the dissection of Calot's triangle. The planned surgery was successful. The operative time and intraoperative blood loss were 157 min and 2 mL, respectively. The patient was discharged from our hospital 3 days after surgery. Application of fluorescent cholangiography during a laparoscopic cholecystectomy for the patients with a right-sided round ligament should be widely accepted.

Fluorescence-Guided Surgery

Surgical resection of cancer remains an important treatment modality. Despite advances in preoperative imaging, surgery itself is primarily guided by the surgeon’s ability to locate pathology with conventional white light imaging. Fluorescence-guided surgery (FGS) can be used to define tumor location and margins during the procedure. Intraoperative visualization of tumors may not only allow more complete resections but also improve safety by avoiding unnecessary damage to normal tissue which can also reduce operative time and decrease the need for second-look surgeries. A number of new FGS imaging probes have recently been developed, complementing a small but useful number of existing probes. In this review, we describe current and new fluorescent probes that may assist FGS.

IRCAD recommendation on safe laparoscopic cholecystectomy

An expert recommendation conference was conducted to identify factors associated with adverse events during laparoscopic cholecystectomy (LC) with the goal of deriving expert recommendations for the reduction of biliary and vascular injury. Nineteen hepato-pancreato-biliary (HPB) surgeons from high-volume surgery centers in six countries comprised the Research Institute Against Cancer of the Digestive System (IRCAD) Recommendations Group. Systematic search of PubMed, Cochrane, and Embase was conducted. Using nominal group technique, structured group meetings were held to identify key items for safer LC. Consensus was achieved when 80% of respondents ranked an item as 1 or 2 (Likert scale 1-4). Seventy-one IRCAD HPB course participants assessed the expert recommendations which were compared to responses of 37 general surgery course participants. The IRCAD recommendations were structured in seven statements. The key topics included exposure of the operative field, appropriate use of energy device and establishment of the critical view of safety (CVS), systematic preoperative imaging, cholangiogram and alternative techniques, role of partial and dome-down (fundus-first) cholecystectomy. Highest consensus was achieved on the importance of the CVS as well as dome-down technique and partial cholecystectomy as alternative techniques. The put forward IRCAD recommendations may help to promote safe surgical practice of LC and initiate specific training to avoid adverse events.

A new fluorescence imaging technique for visualizing hepatobiliary structures using sodium fluorescein: result of a preclinical study in a rat model

BACKGROUND

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

METHODS

Sodium fluorescein solution (1 mL to each individual) were administered intravenously to 20 male Sprague-Dawley rats (6 weeks old, 200-250 g), after laparotomy. Whole abdominal organs were observed under blue light (at a wavelength of 440-490 nm) emitted from a commercialized LED curing light.

RESULTS

Immediately after the tracer solution was administered into the circulatory system of the rat, it was possible to visualize the location of the kidneys and the bile duct under blue light emitted from the light source. The liver was vaguely stained green by the tracer, while the ureters were not. After establishing biliary retention via duct clamping in the left lateral segment of the liver, the green color of the segment became distinct by the tracer, which showed vague coloration following release of the clamp.

CONCLUSION

We established the preclinical basis for using blue light fluorescence cholangiography and liver mapping in this study. The clinical feasibility of these techniques during laparoscopic cholecystectomy and hepatectomy remained to be demonstrated.

Near-infrared cholecystocholangiography with direct intragallbladder indocyanine green injection: preliminary clinical results

BACKGROUND

Near-infrared (NIR) fluorescence cholangiography by systemic administration of indocyanine green (ICG) enhances the visualization of the biliary tree anatomy. However, the simultaneous enhancement of liver parenchyma can disturb the visualization of critical details. We herein proposed a new technique of NIR cholecystocholangiography by intragallbladder ICG injection to increase the safety during laparoscopic cholecystectomy.

METHODS

A total of 46 patients scheduled for laparoscopic cholecystectomy for symptomatic lithiasis (n = 21) or cholecystitis (n = 25) were enrolled. A fluorescence cholangiography by direct gallbladder injection of ICG was performed in all cases. Of them, the ICG was injected through a previously placed percutaneous transhepatic gallbladder drainage catheter (n = 18) or by intraoperative, percutaneous needle puncture of the gallbladder (n = 28). Visualization of biliary structures, including the cystic duct (CD), the common bile and hepatic ducts (CBD and CHD), the gallbladder neck, and the Hartmann's pouch (HP), was performed using White Light (served as control modality) and by NIR enhancement.

RESULTS

Cholecystocholangiography provided a significantly higher rate of visualization of the CD in case of cholecystitis with mild adhesions, and an improved visualization of the HP, CBD, and CHD in case of severe inflammation, when compared to White Light observation. There were no benefits of NIR in case of non-inflamed lithiasis.

CONCLUSIONS

Clinical translation of NIR cholecystocholangiography has been successful with a noise-free visualization of biliary anatomy. It can be considered in difficult cases to increase the safety of laparoscopic cholecystectomy.

Electrically tunable fluidic lens imaging system for laparoscopic fluorescence-guided surgery

The addition of fluorescence guidance in laparoscopic procedures has gained significant interest in recent years, particularly through the use of near infrared (NIR) markers. In this work we present a novel laparoscope camera coupler based on an electrically tunable fluidic lens that permits programmable focus control and has desirable achromatic performance from the visible to the NIR. Its use extends the lower working distance limit and improves detection sensitivity, important for work with molecularly targeted fluorescence markers. We demonstrate its superior optical performance in laparoscopic fluorescence-guided surgery. In vivo results using a tumor specific molecular probe and a nonspecific NIR dye are presented.

Direct Gallbladder Indocyanine Green Injection Fluorescence Cholangiography During Laparoscopic Cholecystectomy

BACKGROUND

Intravenous injection of indocyanine green (ICG) is used to illuminate extrahepatic biliary anatomy. Fluorescence of biliary structures may lower surgical complications that can arise due to inadvertent injury to the common bile duct. We describe a method of injecting ICG directly into the gallbladder to define the cystic duct and common bile duct anatomy.

MATERIALS AND METHODS

A standard laparoscopic cholecystectomy was performed using a laparoscope with near-infrared imaging capability. Before dissection, the gallbladder was punctured with a cholangiogram catheter or a pigtail catheter to aspirate the bile within the gallbladder. The aspirated bile is mixed with ICG solution, which is reinjected into the gallbladder to fluoresce the gallbladder, cystic duct, and common bile duct structures.

RESULTS

Eleven patients underwent direct gallbladder ICG injection for fluorescence cholangiography during cholecystectomy. Direct gallbladder ICG injection clearly defined the extrahepatic biliary anatomy, including the cystic duct-common bile duct junction, by fluorescence. In addition, the dissection plane between the gallbladder and the liver is highlighted with the gallbladder ICG fluorescence.

CONCLUSIONS

Direct gallbladder ICG injection provides immediate visualization of extrahepatic biliary structures and clarifies the dissection plane between the gallbladder and the liver bed.

Heptamethine carbocyanine DZ-1 dye for near-infrared fluorescence imaging of hepatocellular carcinoma

Near-infrared fluorescence (NIRF) dyes have recently emerged as promising tools for non-invasive imaging of different types of cancers. Here, we explored the potential utility of a NIRF DZ-1 dye, with dual imaging and tumour targeting functions, in hepatocellular carcinoma (HCC). We showed the preferential uptake of DZ-1 by HCC cells in vitro and in derived subcutaneous/orthotopic tumour xenografts, accompanied by a minimal effect on normal cells. DZ-1 simplified tumour growth profiling as well, since we were able to correlate NIRF signals with tumour volume and/or tumour-emitting luminescence in mice. Using both orthotopic tumour transplantation and cirrhosis models in parallel, we demonstrated the ability of DZ-1 to differentiate liver tumour from cirrhosis. DZ-1 showed superiority in HCC imaging over indocyanine green by demonstrating significantly enhanced tumour-targeting specificity. At the cellular level, DZ-1 was mainly retained in mitochondria and lysosomes. Additionally, DZ-1 fluorescence spectroscopy has been used for the intraoperative navigation of rabbit liver cancer, to determine surgical margins. We showed that tumor hypoxia and select organic anion-transporting polypeptide genes mediate NIRF dye uptake in HCC, which was supported by clinical evidence. All these findings represent the first evidence that DZ-1 is an effective molecular probe for tumour-specific imaging in HCC, and provide insights into the development of a new generation of imaging agents for intraoperative guidance of cancer surgery.

Indocyanine green fluorescence-guided surgery after IV injection in metastatic colorectal cancer: A systematic review

OBJECTIVE

Indocyanine green fluorescence-guided surgery (ICG-FGS) has emerged as a potential new imaging modality for improving the detection of hepatic, lymph node (LN), and peritoneal metastases in colorectal cancer (CRC) patients. The aim of this paper is to review the available literature in the clinical setting of ICG-FGS for tumoral detection in various fields of metastatic colorectal disease.

METHODS

PubMed and Medline literature databases were searched for original articles on the use of ICG in the setting of clinical studies on colorectal cancer. The search terms used were "near-infrared fluorescence", "intraoperative imaging", "indocyanine green", "human" and "colorectal cancer".

RESULTS

ICG fluorescence imaging (ICG-FI) is clearly supported as an intraoperative technique that allows the detection of additional superficial hepatic metastases of CRC. Data on the role of ICG-FI in the intraoperative detection of peritoneal metastases and LN metastases are scarce but encouraging and ICG-FI could potentially improve the staging and treatment of these patients.

CONCLUSION

ICG-FI is a promising imaging technique in the detection of small infraclinic LN, hepatic, and peritoneal metastatic deposits that may allow better staging and more complete surgical resection with a potential prognostic benefit for patients.

The Best Approach for Laparoscopic Fluorescence Cholangiography: Overview of the Literature and Optimization of Dose and Dosing Time

BACKGROUND

Fluorescence cholangiography using indocyanine green (ICG) can enhance orientation of bile duct anatomy during laparoscopic cholecystectomy. To ensure clear discrimination between bile ducts and liver, the fluorescence ratio between both should be sufficient. This ratio is influenced by the ICG dose and timing of fluorescence imaging. We first systematically identified all strategies for fluorescence cholangiography. Second, we aimed to optimize the dose of ICG and dosing time in a prospective clinical trial.

METHODS

PubMed was searched for clinical trials studying fluorescence cholangiography. Furthermore, 28 patients planned to undergo laparoscopic cholecystectomy were divided into 7 groups, receiving different intravenous doses (5 or 10 mg ICG) at different time points (0.5, 2, 4, 6, or 24 hours prior to surgery).

RESULTS

The systematic review revealed 27 trials including 1057 patients. The majority of studies used 2.5 mg administered within 1 hour before imaging. Imaging 3 to 24 hours after ICG administration was never studied. The clinical trial demonstrated that the highest bile duct-to-liver ratio was achieved 3 to 7 hours after administration of 5 mg and 5 to 25 hours after administration of 10 mg ICG. Up to 3 hours after administration of 5 mg and up to 5 hours after administration of 10 mg ICG, the liver was equally or more fluorescent than the cystic duct, resulting in a ratio ≤1.0.

CONCLUSION

This study shows for the first time that the interval between ICG administration and intraoperative fluorescence cholangiography should be extended. Administering 5 mg ICG at least 3 hours before imaging is easy to implement in everyday clinical practice and results in bile duct-to-liver ratios >1.0.

Applications of fusion-fluorescence imaging using indocyanine green in laparoscopic hepatectomy

BACKGROUND

Indocyanine green (ICG)-fluorescence imaging has been developed for real-time identification of hepatic tumors and segmental boundaries during hepatectomy. Fusion ICG-fluorescence imaging (real-time visualization of pseudocolor-fluorescence signals on white-light color images) may serve as a reliable navigation tool especially in laparoscopic hepatectomy, in which gross inspection and palpation are limited.

METHODS

The study population consisted of 41 patients undergoing laparoscopic hepatectomy. Hepatic tumors were identified by fluorescence imaging following the preoperative intravenous administration of ICG (0.5 mg/kg body weight). To visualize hepatic perfusion and segmental boundaries, ICG (1.25 mg) was injected intravenously during surgery, following closure of the proximal portal pedicle. A laparoscopic imaging system, which enabled superimposition of the pseudocolor-fluorescence images on white color images, was used for the fusion ICG-fluorescence imaging.

RESULTS

Among the 53 malignant tumors resected, fusion ICG-fluorescence imaging revealed 45 nodules (85%), including three nodules of colorectal liver metastasis unidentifiable by white-light color images or intraoperative ultrasonography. It also delineated the segmental boundaries on the hepatic raw surfaces as well as on the phrenic/visceral surfaces in all 12 patients evaluated using this technique.

CONCLUSIONS

Fusion imaging enhances the feasibility of intraoperative ICG-fluorescence imaging in the identification of hepatic tumors and segmental boundaries. It may therefore help surgeons in the safe and accurate completion of laparoscopic hepatectomies.

Identification of Abnormal Biliary Anatomy Utilizing Real-Time Near-Infrared Cholangiography: A Report of Two Cases

Biliary duct anomalies are commonly encountered during laparoscopic cholecystectomy. Advancements in the field of surgery allow for enhanced intraoperative detection of these abnormalities. Fluorophore injection and near-infrared (NIR) imaging can provide real-time intraoperative anatomic feedback without intraoperative delays and ionizing radiation. This report details two cases where the PINPOINT Endoscopic Fluorescence Imaging System (NOVADAQ, Ontario, Canada) was used to identify anomalies of the biliary tree and guide operative decision-making.

Fluorescence cholangiography during laparoscopic cholecystectomy in a patient with situs inversus totalis: a case report and literature review

Background

Situs inversus totalis is a rare autosomal disorder in which the patient’s affected visceral organs are a perfect mirror image of their normal positions. Surgery in these patients is technically challenging. Minimally invasive surgery such as laparoscopic cholecystectomy is the standard treatment for symptomatic cholelithiasis, but it can be difficult to perform. Laparoscopic cholecystectomy in patients with situs inversus totalis may be even more technically challenging. Fluorescence cholangiography is a new innovation in the field of navigation surgery. This procedure is safe and easy to perform, its findings are easy to interpret, and it does not require a learning curve or radiographs. It can be used in real time during surgery to identify extrahepatic biliary structures.

Case presentation

We herein report a case of situs inversus totalis in a Thai patient with a history of biliary pancreatitis. He underwent laparoscopic cholecystectomy with intraoperative fluorescence cholangiography. The operation was successfully completed without complications. To the best of our knowledge, this is the first case report of the use of fluorescence cholangiography during laparoscopic cholecystectomy in a patient with situs inversus.

Conclusion

Fluorescence cholangiographyis a new navigational surgical technique with which to identify extrahepatic biliary structures. It can be used as an adjunct technique during laparoscopic cholecystectomy to avoid biliary tract injury in difficult cases.

Electronic supplementary material

The online version of this article (doi:10.1186/s12893-017-0242-x) contains supplementary material, which is available to authorized users.

Application of Fluorescent Cholangiography for Determination of the Resection Line During a Single-Incision Laparoscopic Cholecystectomy for a Benign Lesion of the Cystic Duct: Preliminary Experience

BACKGROUND

To avoid bile leakage from the stump of a cystic duct that is closed at edematous and/or involved areas, the decision regarding the location of the resection line during a laparoscopic cholecystectomy for benign lesions extending into the cystic duct is important and requires technical ingenuity. For these situations, we used fluorescent cholangiography.

METHODS

Our procedure for single-incision laparoscopic cholecystectomy utilized the SILS-Port, and an additional pair of 5-mm forceps was inserted via an umbilical incision. As a fluorescence source, 1 mL of indocyanine green was intravenously injected after endotracheal intubation of patients in the operating room. A laparoscopic fluorescence imaging system developed by Karl Storz Endoskope was utilized for fluorescent cholangiography.

RESULTS

Fluorescent cholangiography could be used to identify the border of the lesion in the cystic duct. According to the fluorescent cholangiography results, a location for the resection line of the cystic duct could be identified; therefore, the planned resection was successful and produced a histologically negative margin.

CONCLUSIONS

Application of fluorescent cholangiography in the determination of the location of the resection line location during a laparoscopic cholecystectomy for benign lesions of the cystic duct should be widely accepted.

Fluorescence lifetime-based contrast enhancement of indocyanine green-labeled tumors

Although the development of tumor-targeted fluorescent probes is a major area of investigation, it will be several years before these probes are realized for clinical use. Here, we report an approach that employs indocyanine-green (ICG), a clinically approved, nontargeted dye, in conjunction with fluorescence lifetime (FLT) detection to provide high accuracy for tumor-tissue identification in mouse models of subcutaneous human breast and brain tmors. The improved performance relies on the distinct FLTs of ICG within tumors versus tissue autofluorescence and is further aided by the well-known enhanced permeability and retention of ICG in tumors and the clearance of ICG from normal tissue several hours after intravenous injection. We demonstrate that FLT detection can provide more than 98% sensitivity and specificity, and a 10-fold reduction in error rates compared to intensity-based detection. Our studies suggest the significant potential of FLT-contrast for accurate tumor-tissue identification using ICG and other targeted probes under development, both for intraoperative imaging and for ex-vivo margin assessment of surgical specimens.

Fluorescent Imaging With Indocyanine Green During Laparoscopic Cholecystectomy in Patients at Increased Risk of Bile Duct Injury

BACKGROUND

Although rare, injury to the common bile duct (CBD) during laparoscopic cholecystectomy (LC) can be reduced by better intraoperative visualization of the cystic duct (CD) and CBD. The aim of this study was to establish the efficacy of early visualization of the CD and the added value of CBD identification, using near-infrared (NIR) light and the fluorescent agent indocyanine green (ICG), in patients at increased risk of bile duct injury.

MATERIALS AND METHODS

Patients diagnosed with complicated cholecystitis and scheduled for LC were included. The CBD and CD were visualized with NIR light before and during dissection of the liver hilus and at critical view of safety (CVS).

RESULTS

Of the 20 patients originally included, 2 were later excluded due to conversion. In 6 of 18 patients, the CD was visualized early during dissection and prior to imaging with conventional white light. The CBD was additionally visualized with ICG-NIR in 7 of 18 patients. In 1 patient, conversion was prevented due to detection of the CD and CBD with ICG-NIR.

CONCLUSIONS

Early visualization of the CD or additional identification of the CBD using ICG-NIR in patients with complicated cholecystolithiasis can be helpful in preventing CBD injury. Future studies should attempt to establish the optimal dosage and time frame for ICG administration and bile duct visualization with respect to different gallbladder pathologies.

Indocyanine green fluorescence imaging in hepatobiliary surgery

Indocyanine green (ICG) is a fluorescent dye that has been widely used for fluorescence imaging during hepatobiliary surgery. ICG is injected intravenously, selectively taken up by the liver, and then secreted into the bile. The catabolism and fluorescence properties of ICG permit a wide range of visualization methods in hepatobiliary surgery. We have characterized the applications of ICG during hepatobiliary surgery into: 1) liver mapping, 2) cholangiography, 3) tumor visualization, and 4) partial liver graft evaluation. In this literature review, we summarize the current understanding of ICG use during hepatobiliary surgery. Intra-operative ICG fluorescence imaging is a safe, simple, and feasible method that improves the visualization of hepatobiliary anatomy and liver tumors. Intravenous administration of ICG is not toxic and avoids the drawbacks of conventional imaging. In addition, it reduces post-operative complications without any known side effects. ICG fluorescence imaging provides a safe and reliable contrast for extra-hepatic cholangiography when detecting intra-hepatic bile leakage following liver resection. In addition, liver tumors can be visualized and well-differentiated hepatocellular carcinoma tumors can be accurately identified. Moreover, vascular reconstruction and outflow can be evaluated following partial liver transplantation. However, since tissue penetration is limited to 5-10mm, deeper tissue cannot be visualized using this method. Many instances of false positive or negative results have been reported, therefore further characterization is required.

Multimodal Magnetic Resonance and Near-Infrared-Fluorescent Imaging of Intraperitoneal Ovarian Cancer Using a Dual-Mode-Dual-Gadolinium Liposomal Contrast Agent

The degree of tumor removal at surgery is a major factor in predicting outcome for ovarian cancer. A single multimodality agent that can be used with magnetic resonance (MR) for staging and pre-surgical planning, and with optical imaging to aid surgical removal of tumors, would present a new paradigm for ovarian cancer. We assessed whether a dual-mode, dual-Gadolinium (DM-Dual-Gd-ICG) contrast agent can be used to visualize ovarian tumors in the peritoneal cavity by multimodal MR and near infra-red imaging (NIR). Intraperitoneal ovarian tumors (Hey-A8 or OVCAR3) in mice enhanced on MR two days after intravenous DM-Dual Gd-ICG injection compared to controls (SNR, CNR, p < 0.05, n = 6). As seen on open abdomen and excised tumors views and confirmed by optical radiant efficiency measurement, Hey-A8 or OVCAR3 tumors from animals injected with DM-Dual Gd-ICG had increased fluorescence (p < 0.05, n = 6). This suggests clinical potential to localize ovarian tumors by MR for staging and surgical planning, and, by NIR at surgery for resection.