Near infrared fluorescence lymphatic laparoscopy of the colon and mesocolon

[Fluorescence-guided detection of lymph node metastases of gastrointestinal tumors]

A correct lymph node (LN) staging is essential in oncological surgery. Indocyanine green (ICG) near-infrared fluorescence (NIRF) guided sentinel lymph node (SLN) navigation is a relatively novel technique. The aim of this review is to analyze the impact of ICG-NIRF on identification of LN metastases of gastrointestinal tumors. The Scopus and PubMed/MEDLINE literature databases were searched and 20 studies were included. The ICG-NIRF navigation of LN has been shown to enable and improve LN detection in gastrointestinal tumors; however, the mean detection, sensitivity, accuracy and false negative rates show substantial variation. This could be due to both the heterogeneous techniques applied and to the low retention of ICG by lymph nodes. Fluorescence imaging to identify LN drainage is a promising tool to improve oncological outcomes. Nonetheless, the technique requires further development in terms of hardware, software and fluorophores, which are currently being investigated.

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.

In vivo and ex vivo sentinel node mapping does not identify the same lymph nodes in colon cancer

INTRODUCTION

Identification of lymph nodes and pathological analysis is crucial for the correct staging of colon cancer. Lymph nodes that drain directly from the tumor area are called "sentinel nodes" and are believed to be the first place for metastasis. The purpose of this study was to perform sentinel node mapping in vivo with indocyanine green and ex vivo with methylene blue in order to evaluate if the sentinel lymph nodes can be identified by both techniques.

METHODS

Patients with colon cancer UICC stage I-III were included from two institutions in Denmark from February 2015 to January 2016. In vivo sentinel node mapping with indocyanine green during laparoscopy and ex vivo sentinel node mapping with methylene blue were performed in all patients.

RESULTS

Twenty-nine patients were included. The in vivo sentinel node mapping was successful in 19 cases, and ex vivo sentinel node mapping was successful in 13 cases. In seven cases, no sentinel nodes were identified. A total of 51 sentinel nodes were identified, only one of these where identified by both techniques (2.0%). In vivo sentinel node mapping identified 32 sentinel nodes, while 20 sentinel nodes were identified by ex vivo sentinel node mapping. Lymph node metastases were found in 10 patients, and only two had metastases in a sentinel node.

CONCLUSION

Placing a deposit in relation to the tumor by indocyanine green in vivo or of methylene blue ex vivo could only identify sentinel lymph nodes in a small group of patients.

Intraoperative fluorescence imaging to localize tumors and sentinel lymph nodes in rectal cancer

Tumor involvement at the resection margin remains the most important predictor for local recurrence in patients with rectal cancer. A careful description of tumor localization is therefore essential. Currently, endoscopic tattooing with ink is customary, but visibility during laparoscopic resections is limited. Near-infrared (NIR) fluorescence imaging using indocyanine green (ICG) could be an improvement. In addition to localize tumors, ICG can also be used to identify sentinel lymph nodes (SLNs). The feasibility of this new technique was explored in five patients undergoing laparoscopic low anterior resection for rectal cancer. Intraoperative tumor visualization was possible in four out of five patients. Fluorescence signal could be detected 32 ± 18 minutes after incision, while ink could be detected 42 ± 21 minutes after incision (p = 0.53). No recurrence was diagnosed within three months after surgery. Ex vivo imaging identified a mean of 4.2 ± 2.7 fluorescent lymph nodes, which were appointed SLNs. One out of a total of 83 resected lymph nodes contained a micrometastasis. This node was not fluorescent. This technical note describes the feasibility of endoscopic tattooing of rectal cancer using ICG:nanocolloid and NIR fluorescence imaging during laparoscopic resection. Simultaneous SLN mapping was also feasible, but may be less reliable due to neoadjuvant therapy.

Intraoperative imaging-guided cancer surgery: from current fluorescence molecular imaging methods to future multi-modality imaging technology

Cancer is a major threat to human health. Diagnosis and treatment using precision medicine is expected to be an effective method for preventing the initiation and progression of cancer. Although anatomical and functional imaging techniques such as radiography, computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET) have played an important role for accurate preoperative diagnostics, for the most part these techniques cannot be applied intraoperatively. Optical molecular imaging is a promising technique that provides a high degree of sensitivity and specificity in tumor margin detection. Furthermore, existing clinical applications have proven that optical molecular imaging is a powerful intraoperative tool for guiding surgeons performing precision procedures, thus enabling radical resection and improved survival rates. However, detection depth limitation exists in optical molecular imaging methods and further breakthroughs from optical to multi-modality intraoperative imaging methods are needed to develop more extensive and comprehensive intraoperative applications. Here, we review the current intraoperative optical molecular imaging technologies, focusing on contrast agents and surgical navigation systems, and then discuss the future prospects of multi-modality imaging technology for intraoperative imaging-guided cancer surgery.

Image-guided cancer surgery using near-infrared fluorescence

Paradigm shifts in surgery arise when surgeons are empowered to perform surgery faster, better and less expensively than current standards. Optical imaging that exploits invisible near-infrared (NIR) fluorescent light (700-900 nm) has the potential to improve cancer surgery outcomes, minimize the time patients are under anaesthesia and lower health-care costs largely by way of its improved contrast and depth of tissue penetration relative to visible light. Accordingly, the past few years have witnessed an explosion of proof-of-concept clinical trials in the field. In this Review, we introduce the concept of NIR fluorescence imaging for cancer surgery, examine the clinical trial literature to date and outline the key issues pertaining to imaging system and contrast agent optimization. Although NIR seems to be superior to many traditional imaging techniques, its incorporation into routine care of patients with cancer depends on rigorous clinical trials and validation studies.

Ex vivo sentinel node mapping in colon cancer combining blue dye staining and fluorescence imaging

BACKGROUND

The sentinel lymph node procedure has been proposed to improve nodal staging in colon cancer patients. The aim of this study was to assess the added value of near-infrared (NIR) fluorescence imaging to conventional blue dye staining for ex vivo sentinel lymph node mapping.

MATERIALS AND METHODS

We included 22 consecutive patients undergoing surgery for colon cancer. After tumor resection, we submucosally injected a premixed cocktail of the near-infrared lymphatic tracer HSA800 and blue dye around the tumor for detection of sentinel lymph nodes. We used the Mini-FLARE imaging system for fluorescence imaging.

RESULTS

In 95% of patients, we identified at least one sentinel lymph node. Overall, a total of 77 sentinel lymph nodes were identified, 77 of which were fluorescent (100%) and 70 of which were blue (91%). Sentinel lymph nodes that were located deeper in the mesenteric fat could easily be located by NIR fluorescence. In four of five patients with lymph node metastases, tumor cells were present in at least one of the sentinel lymph nodes.

CONCLUSIONS

This study shows the successful use and added value of the NIR fluorescence tracer HSA800 to conventional blue dye for the ex vivo sentinel lymph node procedure in colon cancer.

Advanced intraoperative imaging methods for laparoscopic anatomy navigation: an overview

BACKGROUND

Safety and efficiency are important topics in minimally invasive surgery. Apart from its advantages, laparoscopic surgery has the following drawbacks: two-dimensional imaging, challenging eye-hand coordination, and absence of tactile feedback. Enhanced imaging with earlier and clearer identification of essential tissue types can partly overcome these disadvantages. Research groups worldwide are investigating new technologies for image-guided surgery purposes. This review article gives an overview of current developments in surgical optical imaging for improved anatomic identification and physiologic tissue characterization during laparoscopic gastrointestinal surgery.

METHODS

A systematic literature search in the PubMed database was conducted. Eligible studies reported on any kind of novel optical imaging technique applied for anatomic identification or physiologic tissue characterization in laparoscopic gastrointestinal surgery. Gynecologic and urologic procedures also were included whenever vascular, nerve, ureter, or lymph node imaging was concerned.

RESULTS

Various surgical imaging techniques for enhanced intraoperative visualization of essential tissue types (i.e., blood vessel, bile duct, ureter, nerve, lymph node) and for tissue characterization purposes such as assessment of blood perfusion were identified. An overview of preclinical and clinical experiences is given as well as the potential added value for intraoperative anatomic localization and characterization during laparoscopy.

CONCLUSION

Implementation of new optical imaging methods during laparoscopic gastrointestinal surgery can improve intraoperative anatomy navigation. This may lead to increased patient safety (preventing iatrogenic functional tissue injury) and procedural efficiency (shorter operating time). Near-infrared fluorescence imaging seems to possess the greatest potential for implementation in clinical practice in the near future.

Fluorescence cholangiography during laparoscopic cholecystectomy: a feasibility study on early biliary tract delineation

BACKGROUND

Laparoscopic cholecystectomy (LC) is one of the most commonly performed laparoscopic procedures. Bile duct injury is a rare but serious complication during this procedure, mostly caused by misidentification of the extrahepatic bile duct anatomy. Intraoperative cholangiography may be helpful to reduce the risk of bile duct injury; however, this is not a common procedure worldwide. Near-infrared fluorescence cholangiography (NIRFC) using indocyanine green (ICG) is a promising alternative for the identification of the biliary tree. This prospective observational study was designed to assess the feasibility and image quality of intermittent NIRFC during LC, using a newly developed laparoscopic fluorescence system.

METHODS

Consecutive patients undergoing elective LC were included and received a single intravenous injection of ICG directly after induction of anesthesia. During dissection of the base of the gallbladder and the cystic duct, the extrahepatic bile ducts were visualized by using a dedicated laparoscope, which offers both conventional state-of-the-art imaging and fluorescence imaging. Intraoperative recognition of the biliary structures was registered at set time points, as well as the establishment of the critical view of safety.

RESULTS

Fifteen patients were included between December 2011 and May 2012. ICG was visible in the liver and bile ducts within 20 min after intravenous administration and remained for approximately 2 h, using the fluorescence mode of the laparoscope. The common bile duct and cystic duct could be clearly identified at an early stage of the operation and, more important, significantly earlier than with the conventional camera mode. No per- or postoperative complications occurred as a consequence of ICG use.

CONCLUSIONS

Intermittent fluorescence imaging using a newly developed laparoscope and preoperative administration of ICG seems a useful aid in accelerating visualization of the extrahepatic bile ducts during laparoscopic cholecystectomy.