Sentinel node mapping guided by indocyanine green fluorescence imaging: a new method for sentinel node navigation surgery in gastrointestinal cancer

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.

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.

From Illusion to Reality: A Brief History of Robotic Surgery

PURPOSE

Robotic surgery is currently employed for many surgical procedures, yielding interesting results.

METHODS

We performed an historical review of robots and robotic surgery evaluating some critical phases of its evolution, analyzing its impact on our life and the steps completed that gave the robotics its current popularity.

RESULTS

The origins of robotics can be traced back to Greek mythology. Different aspects of robotics have been explored by some of the greatest inventors like Leonardo da Vinci, Pierre Jaquet-Droz, and Wolfgang Von-Kempelen. Advances in many fields of science made possible the development of advanced surgical robots. Over 3000 da Vinci robotic platforms are installed worldwide, and more than 200 000 robotic procedures are performed every year.

CONCLUSION

Despite some potential adverse events, robotic technology seems safe and feasible. It is strictly linked to our life, leading surgeons to a new concept of surgery and training.

[Development of a near-infrared fluorescence imaging system based on fluorescence properties of methylene blue]

OBJECTIVE

To develop a near-infrared fluorescence imaging system based on the fluorescence properties of methylene blue.

METHODS

According to the optical properties of methylene blue, we used a custom-made specific LED light source and an interference filter, a CCD camera and other relevant components to construct the near-infrared fluorescence imaging system. We tested the signal-to-background ratio (SBR) of this imaging system for detecting methylene blue under different experimental conditions and analyzed the SBR in urine samples collected from 15 Wistar rats with intravenous injection of methylene blue at the doses of 0, 1.4, 1.6, 1.8, or 2.0 0 mg/kg methylene blue.

RESULTS

The SBR of this imaging system for detecting methylene blue was affected by the concentration of methylene blue and the distance from the sample (P<0.05). In the urine samples from Wistar rats, the SBR varied with the the injection dose, and the rats injected with 1.6 mg/kg methylene blue showed the highest SBR (8.71∓0.20) in the urine (P<0.05).

CONCLUSION

This near-infrared fluorescence imaging system is useful for fluorescence detection of methylene blue and can be used for real-time recognition of ureters during abdominal surgery.

Feasibility of fluorescence lymph node imaging in colon cancer: FLICC

BACKGROUND

In colon cancer, appropriate tumour excision and associated lymphadenectomy directly impact recurrence and survival outcomes. Currently, there is no standard for mesenteric lymphadenectomy, with a lymph node yield of 12 acting as a surrogate quality marker. Our goal was to determine the safety and feasibility of indocyanine green (ICG) fluorescence imaging to demonstrate lymphatic drainage in colon cancer in a dose-escalation study.

METHODS

A prospective pilot study of colon cancer patients undergoing curative laparoscopic resection was performed. At surgery, peritumoural subserosal ICG injection was done to demonstrate lymphatic drainage of the tumour. A specialized fluorescence system excited the ICG and assessed lymphatics in real time. The primary outcome was the feasibility of ICG fluorescent lymphangiography for lymphatic drainage in colon cancer. Secondary outcomes were the optimal protocol for dose, injection site, and ICG lymphatic mapping timing.

RESULTS

Ten consecutive patients were evaluated (six males, mean age 69.5 years). In all, lymphatic channels were seen around the tumour to a varying extent. Eight (80%) had drainage to the sentinel node. In all cases where the lymphatic map was seen, there was no further spread 10 min after injection. In 2 patients (20%), additional lymph nodes located outside of the proposed resection margins were demonstrated. In both cases the resection was extended to include the nodes and in both patients these nodes were positive on histopathology. Factors contributing to reduced lymphatic visualization were inadequate ICG concentrations, excess India ink blocking drainage, and inflammation from tattoo placement.

CONCLUSIONS

ICG can be safely injected into the peritumoural subserosal and demonstrate lymphatic drainage in colon cancer. This proof of concept and proposed standards for the procedure can lead to future studies to optimize the application of image-guided precision surgery in colon cancer. Furthermore, this technique may be of value in indicating the need for more extended lymphadenectomy.

Diagnostic evaluation of sentinel lymph node biopsy using indocyanine green and infrared or fluorescent imaging in gastric cancer: a systematic review and meta-analysis

BACKGROUND

Sentinel node navigation surgery (SNNS) for gastric cancer using infrared visualization of indocyanine green (ICG) is intriguing because it may limit operative morbidity. We are the first to systematically review and perform meta-analysis on the diagnostic utility of ICG and infrared electronic endoscopy (IREE) or near infrared fluorescent imaging (NIFI) for SNNS exclusively in gastric cancer.

METHODS

A search of electronic databases MEDLINE, EMBASE, SCOPUS, Web of Science, and the Cochrane Library using search terms "gastric/stomach" AND "tumor/carcinoma/cancer/neoplasm/adenocarcinoma/malignancy" AND "indocyanine green" was completed in May 2017. Articles were selected by two independent reviewers based on the following major inclusion criteria: (1) diagnostic accuracy study design; (2) indocyanine green was injected at tumor site; (3) IREE or NIFI was used for intraoperative visualization. 327 titles or abstracts were screened. The quality of included studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2.

RESULTS

Ten full text studies were selected. 643 patients were identified with the majority of patients possessing T1 tumors (79.8%). Pooled identification rate, diagnostic odds ratio, sensitivity, and specificity were 0.99 (0.97-1.0), 380.0 (68.71-2101), 0.87 (0.80-0.93), and 1.00 (0.99-1.00), respectively. The summary receiver operator characteristic for ICG + IREE/NIFI demonstrated a test accuracy of 98.3%. Subgroup analysis found improved test performance for studies with low-risk QUADAS-2 scores, studies published after 2010 and submucosal ICG injection. IREE had improved diagnostic odds ratio, sensitivity, and identification rate compared to NIFI. Heterogeneity among studies ranged from low (I² < 25%) to high (I² > 75%).

CONCLUSIONS

We found encouraging results regarding the accuracy, diagnostic odds ratio, and specificity of the test. The sensitivity was not optimal but may be improved by a strict protocol to augment the technique. Given the number and heterogeneity of studies, our results must be viewed with caution.

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.

Developments in optical imaging for gastrointestinal surgery

To improve outcomes for patients with cancer, in terms of both survival and a reduction in the morbidity and mortality that results from surgical resection and treatment, there are two main areas that require improvement. Accurate early diagnosis of the cancer, at a stage where curative and, ideally, minimally invasive treatment is achievable, is desired as well as identification of tumor margins, lymphatic and distant disease, enabling complete, but not unnecessarily extensive, resection. Optical imaging is making progress in achieving these aims. This review discusses the principles of optical imaging, focusing on fluorescence and spectroscopy, and the current research that is underway in GI tract carcinomas.

Using fluorescence lymphangiography to define the ileocolic mesentery: proof of concept for the watershed area using real-time imaging

Recent advances in mesenteric science have demonstrated that the mesentery is a continuous structure with a 'watershed' area at the mesenteric apex between the right colon and terminal ileum, where lymphatic flow can proceed either proximally or distally. With this new understanding of the anatomy, functional features are emerging, which can have an impact on surgical management. Fluorescence lymphangiography or lymphoscintigraphy with indocyanine green allows real-time visualization of lymphatic channels, which highlights sentinel lymph nodes and may facilitate identification of the ideal margins for mesenteric lymphadenectomy during bowel resection for colon cancer. By using this novel technology, it is possible to demonstrate a watershed area in the ileocolic region and may facilitate more precise mesenteric dissection. In the present study, we provide proof of concept for the ileocolic watershed area using fluorescence lymphangiography.

A pilot study of lymph node mapping with indocyanine green in robotic gastrectomy for gastric cancer

OBJECTIVES

Robotic gastrectomy has become increasingly popular in the treatment of gastric cancer, especially in Asian countries. The use of indocyanine green fluorescence has been reported in lymphatic mapping for gastric cancer in laparoscopic gastrectomy; however, there have been few reports regarding the use of indocyanine green in robotic gastrectomy.

METHODS

From January 2011 to March 2016, a total of 79 patients underwent robotic gastrectomy for gastric cancer. Among them, intraoperative subserosal injection (n = 9) or preoperative submucosal injection (n = 5) of indocyanine green with near-infrared imaging was performed in 14 patients, and the other 65 patients underwent robotic gastrectomy without the use of indocyanine green.

RESULTS

There was no significant difference in the operative time, total number of retrieved lymph nodes, operative blood loss, and postoperative hospital stay between the patients who underwent robotic gastrectomy with or without indocyanine green fluorescence. For each lymph node station, there was significantly more number of retrieved lymph nodes in the indocyanine green group than in the no-indocyanine green group at the greater curvature side of the low body (#4d) to the infrapyloric region (#6) of the stomach. Five of the 14 patients who received an indocyanine green injection for lymphatic mapping had lymph node metastasis, and metastatic lymph nodes were located in the lymph node stations as detected by indocyanine green fluorescence during surgery.

CONCLUSION

Indocyanine green fluorescence with near-infrared imaging is feasible and is a promising method of lymphatic mapping in robotic gastrectomy for gastric cancer. In future studies, larger patient numbers and long-term follow-up are required.

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.

Prevalence of anastomotic leak and the impact of indocyanine green fluorescein imaging for evaluating blood flow in the gastric conduit following esophageal cancer surgery

BACKGROUNDS AND AIM

Anastomotic leak (AL) following esophagectomy for esophageal cancer (EC) remains an important cause of prolonged hospitalization and impaired quality of life. Recently, indocyanine green (ICG) fluorescein imaging has been used to evaluate the gastric conduit blood supply during EC surgery. Although several factors have been reported to be associated with AL, no studies have evaluated the relationships between risk factors for AL, including ICG fluorescein imaging. The purpose of this study was to investigate the risk factors associated with AL following esophagectomy and to evaluate the impact of ICG fluorescein imaging of the gastric conduit during EC surgery.

METHODS

One hundred and twenty patients undergoing esophagectomy with esophagogastric anastomosis for EC were enrolled in this retrospective study. Clinicopathological factors, preoperative laboratory variables, and surgical factors, including ICG fluorescence imaging, were analyzed to determine their association with AL. Univariate and multivariate logistic regression analysis was used to evaluate the impact of each of these factors on the incidence of AL.

RESULTS

Among the 120 patients enrolled in the study, 10 (8.3%) developed AL. Univariate analysis demonstrated an increased risk of AL in patients with a high-neutrophil-to-lymphocyte ratio (p = 0.0500) and in patients who did not undergo ICG fluorescein imaging (p = 0.0057). Multivariate analysis revealed that the absence of ICG imaging was an independent risk factor for AL (p = 0.0098).

CONCLUSIONS

Using ICG fluorescein imaging to evaluate blood flow in the gastric conduit might decrease the incidence of AL following EC surgery.

Sensitivity and specificity of indocyanine green near-infrared fluorescence imaging in detection of metastatic lymph nodes in colorectal cancer: Systematic review and meta-analysis

This review aimed to determine the overall sensitivity and specificity of indocyanine green (ICG) near-infrared (NIR) fluorescence in sentinel lymph node (SLN) detection in Colorectal cancer (CRC). A systematic search in electronic databases was conducted. Twelve studies including 248 patients were reviewed. The median sensitivity, specificity, and accuracy rates were 73.7, 100, and 75.7. The pooled sensitivity and specificity rates were 71% and 84.6%. In conclusion, ICG-NIR fluorescence is a promising technique for detecting SLNs in CRC.

Laparoscopic sentinel node navigation surgery for early gastric cancer

Currently, the most accurate method for identifying lymph node metastasis is intraoperative diagnosis by sentinel node (SN) biopsy. Based on the SNNS study-a recent large-scale, nationwide, multicenter prospective study-the SN concept seems to be scientifically valid in patients with early gastric cancer. SN biopsy is a multistep technique consisted of six essential elements: indication, the selection of a tracer, a proper tracer injection method, the objective detection of SNs, a reliable biopsy technique, and the precise detection of nodal metastasis. For SN biopsy of gastric cancer, these elements have been validated as follows: the indication should be limited to clinical T1 less than 4 cm in diameter; combination mapping with radioactive colloid and blue dye is used as the standard; and endoscopic submucosal injection is the standard tracer injection. Detection of SNs and a reliable biopsy technique are enabled by adaptation of lymphatic basin dissection, a proper biopsy technique for gastric cancer. Lymphatic basin dissection is a selective lymphadenectomy procedure for dissecting basins en bloc, collecting lymph nodes and lymphatic vessels stained with dye. Lymphatic basin dissection is superior to the ordinary pick-up method, not only for minimizing the rate of missed SNs, but also in terms of oncological safety as it complements an intraoperative frozen section diagnosis by serving as a backup dissection. Moreover, indocyanine green (ICG) fluorescence mapping has been developed in recent years. ICG fluorescence mapping is superior because of its high sensitivity and signal stability. Moreover, it is feasible for both open and laparoscopic gastrectomy in treating early gastric cancer. SN biopsy has brought dramatic changes to laparoscopic surgery for early gastric cancer. With laparoscopic SN biopsy using ICG fluorescence navigation, laparoscopic surgery for early gastric cancer has changed from the uniform standard gastrectomy with D1+ into a tailor-made function-preserving surgical procedure, such as local resection with lymphatic basin dissection.

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.

Sentinel node navigation in gastric cancer: new horizons for personalized minimally invasive surgical oncology?

Complete (R0) resection and regional lymph nodes (LNs) dissection represent undoubtedly the basic surgical tools for patients with gastric cancer. It is reported that the LN metastasis rate in patients with early gastric cancer (EGC) is approximately 15-20%. Therefore, the innovative clinical application of sentinel node navigation surgery (SNNS) for EGC might be able to prevent unnecessary LN dissection as well as to reduce significantly the volume of gastric resection. Recent evidence suggests that double tracer methods appear superior compared to single tracer techniques. However, the researchers' interest is now focused on the identification of new LN detection methods utilizing sophisticated technology such as infrared ray endoscopy, fluorescence imaging and near-infrared technology. Despite its notable limitations, hematoxylin-eosin is still considered the mainstay staining for assessing the metastatic status of LNs. In this review, we summarize the current evidences and we provide the latest scientific information assessing safety, efficacy and potential limitations of the innovative sentinel node (SN) navigation technique for gastric cancer. We try also to provide a "view" towards a future potential application of personalized minimally invasive surgery in gastric cancer field.

Laparoscopic sentinel node navigation surgery for early gastric cancer: a prospective multicenter trial

BACKGROUND

Prospective multicenter trials have shown the feasibility of sentinel node (SN) navigation surgery using a dual tracer of dye and radioisotope for early gastric cancer. However, comparable trials using the indocyanine green (ICG) and the infrared ray laparoscopic system (IRLS) have not been reported. On the basis of our cohort studies, we assumed that the ICG imaging with the IRLS is as effective as the dual tracer in detecting SNs. Therefore, we conducted a prospective multicenter trial to assess the effectiveness and generalizability of the infrared ICG technique in patients with early gastric cancer.

PATIENTS AND METHODS

Patients with previously untreated cT1 gastric adenocarcinomas less than 4 cm in gross diameter were eligible for inclusion in this study. SN mapping was performed by using ICG combined with IRLS technique. Following biopsy of the identified SNs, D2 or modified D2 laparoscopic gastrectomy was performed according to the current Japanese Gastric Cancer Association guidelines.

RESULTS

Among the 47 patients who gave written informed consent, 44 were eligible from the surgical findings, for whom SN biopsy was performed. The detection rate of the lymphatic basin by the ICG with IRLS was 100% (44/44). The accuracy was also 100% (7/7) for detecting metastatic lymph node, which was verified on the permanent pathologic examination. Following the median follow-up of 114 months (range, 60 to 120 months), no recurrence (0/40) was observed. Although the number of patients was unequally distributed among the hospitals participating in the trial, the detection rates of SNs in low-volume hospitals were comparable to those in high-volume hospitals. Consequently, there was no learning curve in this trial.

CONCLUSION

The infrared ICG imaging accurately detected the lymphatic basin and SNs with occult metastasis in SN-navigated gastrectomy for gastric cancer. This method was feasible even for low-volume surgeons and hospitals.

Future of Minimally Invasive Colorectal Surgery

Minimally invasive surgery is slowly taking over as the preferred operative approach for colorectal diseases. However, many of the procedures remain technically difficult. This article will give an overview of the state of minimally invasive surgery and the many advances that have been made over the last two decades. Specifically, we discuss the introduction of the robotic platform and some of its benefits and limitations. We also describe some newer techniques related to robotics.

Clinical application of indocyanine green-fluorescence imaging during hepatectomy

In hepatobiliary surgery, the fluorescence and bile excretion of indocyanine green (ICG) can be used for real-time visualization of biological structure. Fluorescence cholangiography is used to obtain fluorescence images of the bile ducts following intrabiliary injection of 0.025-0.5 mg/mL ICG or intravenous injection of 2.5 mg ICG. Recently, the latter technique has been used in laparoscopic/robotic cholecystectomy. Intraoperative fluorescence imaging can be used to identify subcapsular hepatic tumors. Primary and secondary hepatic malignancy can be identified by intraoperative fluorescence imaging using preoperative intravenous injection of ICG through biliary excretion disorders that exist in cancerous tissues of hepatocellular carcinoma (HCC) and in non-cancerous hepatic parenchyma around adenocarcinoma foci. Intraoperative fluorescence imaging may help detect tumors to be removed, especially during laparoscopic hepatectomy, in which visual inspection and palpation are limited, compared with open surgery. Fluorescence imaging can also be used to identify hepatic segments. Boundaries of hepatic segments can be visualized following injection of 0.25-2.5 mg/mL ICG into the portal veins or by intravenous injection of 2.5 mg ICG following closure of the proximal portal pedicle toward hepatic regions to be removed. These techniques enable identification of hepatic segments before hepatectomy and during parenchymal transection for anatomic resection. Advances in imaging systems will increase the use of fluorescence imaging as an intraoperative navigation tool that can enhance the safety and accuracy of open and laparoscopic/robotic hepatobiliary surgery.

Optimal settings and accuracy of indocyanine green fluorescence imaging for sentinel node biopsy in early gastric cancer

Indocyanine green (ICG) fluorescence imaging represents a promising method for sentinel node (SN) biopsy in laparoscopic gastric surgery due to its signal stability. In the present study, the suitability and optimal settings of ICG fluorescence imaging for SN biopsy in early gastric cancer were determined. Patients with single primary superficial-type adenocarcinoma of the stomach, lesions <5 cm in diameter, and no evident nodal metastasis and out of indication for endoscopic submucosal dissection were enrolled. The day prior to surgery, ICG solution was endoscopically injected into four quadrants of the submucosal layer of the tumor. The Photodynamic Eye was used to detect ICG fluorescence. Bright nodes were defined as clearly fluorescent nodes. A total of 72 patients were enrolled; 11 cases presented with metastasis, and of these, 10 could be diagnosed by bright node biopsy. The adequate concentration and injection volume of ICG was determined to be 50 µg/ml (×100) and 0.5 mlx4 points, respectively. There was 1 false-negative case, and this was attributed to the failure of the frozen section diagnosis. These results suggested that ICG fluorescence imaging for SN biopsy in laparoscopic surgery for early gastric cancer is feasible. However, a weakness of ICG fluorescence imaging is the subjectivity of bright node evaluation.

Indocyanine green delivery systems for tumour detection and treatments

Indocyanine green (ICG) is a cyanine compound that displays fluorescent properties in the near infrared region. This dye is employed for numerous indications but nowadays its major application field regards tumour diagnosis and treatments. Optical imaging by near infrared fluorescence provides news opportunities for oncologic surgery. The imaging of ICG can be useful for intraoperative identification of several solid tumours and metastases, and sentinel lymph node detection. In addition, ICG can be used as an agent for the destruction of malignant tissue, by virtue of the production of reactive oxygen species and/or induction of a hyperthermia effect under irradiation. Nevertheless, ICG shows several drawbacks, which limit its clinical application. Several formulative strategies have been studied to overcome these problems. The rationale of the development of ICG containing drug delivery systems is to enhance the in vivo stability and biodistribution profile of this dye, allowing tumour accumulation and resulting in better efficacy. In this review, ICG containing nano-sized carriers are classified based on their chemical composition and structure. In addition to nanosystems, different formulations including hydrogel, microsystems and others loaded with ICG will be illustrated. In particular, this report describes the preparation, in vitro characterization and in vivo application of ICG platforms for cancer imaging and treatment. The promising results of all systems confirm their clinical utility but further studies are required prior to evaluating the formulations in human trials.

Near-infrared fluorescence sentinel lymph node detection in gastric cancer: A pilot study

AIM: To investigate feasibility and accuracy of near-infrared fluorescence imaging using indocyanine green: nanocolloid for sentinel lymph node (SLN) detection in gastric cancer.

METHODS: A prospective, single-institution, phase I feasibility trial was conducted. Patients suffering from gastric cancer and planned for gastrectomy were included. During surgery, a subserosal injection of 1.6 mL ICG:Nanocoll was administered around the tumor. NIR fluorescence imaging of the abdominal cavity was performed using the Mini-FLARE™ NIR fluorescence imaging system. Lymphatic pathways and SLNs were visualized. Of every detected SLN, the corresponding lymph node station, signal-to-background ratio and histopathological diagnosis was determined. Patients underwent standard-of-care gastrectomy. Detected SLNs outside the standard dissection planes were also resected and evaluated.

RESULTS: Twenty-six patients were enrolled. Four patients were excluded because distant metastases were found during surgery or due to technical failure of the injection. In 21 of the remaining 22 patients, at least 1 SLN was detected by NIR Fluorescence imaging (mean 3.1 SLNs; range 1-6). In 8 of the 21 patients, tumor-positive LNs were found. Overall accuracy of the technique was 90% (70%-99%; 95%CI), which decreased by higher pT-stage (100%, 100%, 100%, 90%, 0% for respectively Tx, T1, T2, T3, T4 tumors). All NIR-negative SLNs were completely effaced by tumor. Mean fluorescence signal-to-background ratio of SLNs was 4.4 (range 1.4-19.8). In 8 of the 21 patients, SLNs outside the standard resection plane were identified, that contained malignant cells in 2 patients.

CONCLUSION: This study shows successful use of ICG:Nanocoll as lymphatic tracer for SLN detection in gastric cancer. Moreover, tumor-containing LNs outside the standard dissection planes were identified.

Sentinel lymph node navigation surgery for gastric cancer: Does it really benefit the patient?

Sentinel lymph node (SLN) navigation surgery is accepted as a standard treatment procedure for malignant melanoma and breast cancer. However, the benefit of reduced lymphadenectomy based on SLN examination remains unclear in cases of gastric cancer. Here, we review previous studies to determine whether SLN navigation surgery is beneficial for gastric cancer patients. Recently, a large-scale prospective study from the Japanese Society of Sentinel Node Navigation Surgery reported that the endoscopic dual tracer method, using a dye and radioisotope for SLN biopsy, was safe and effective when applied to cases of superficial and relatively small gastric cancers. SLN mapping with SLN basin dissection was preferred for early gastric cancer since it is minimally invasive. However, previous studies reported that limited gastrectomy and lymphadenectomy may not improve the patient’s postoperative quality of life (QOL). As a result, the benefit of SLN navigation surgery for gastric cancer patients, in terms of their QOL, is limited. Thus, endoscopic and laparoscopic limited gastrectomy combined with SLN navigation surgery has the potential to become the standard minimally invasive surgery in early gastric cancer.

Sentinel node navigation surgery with indocyanine green fluorescence-guided method for metachronous early gastric carcinoma arising from reconstructed gastric tube after esophagectomy

A 67-year-old man who had undergone a thoracoscopic esophagectomy and posterior mediastinal gastric tube reconstruction for thoracic esophageal cancer 9 years previously was endoscopically diagnosed as having gastric carcinoma arising from the reconstructed gastric tube. No evidence of metastasis was seen in imaging examinations, and the depth of tumor invasion was suspected to be the submucosal layer. Based on these results, we decided that surgery, rather than endoscopic resection, was indicated. The tumor was located in the upper abdomen. Therefore, we performed a partial resection of the gastric tube. Sentinel nodes (SN) were identified using the Hyper Eye Medical System II. Metastasis was not observed in any of the selected SN. While the treatment strategy for gastric tube cancer after an esophagectomy remains controversial, minimally invasive surgery with sentinel node navigation surgery appears to be clinically useful. However, the method of SN dissection should be investigated with due consideration given to arterial preservation.

Impact of Obesity on Sentinel Lymph Node Mapping in Patients with Newly Diagnosed Uterine Cancer Undergoing Robotic Surgery

PURPOSE

The aim of this study was to determine the impact of obesity on the rate of successful sentinel lymph node (SLN) mapping in patients with uterine cancer undergoing robotic surgery, and compare SLN detection rates using indocyanine green (ICG) versus blue dye.

METHODS

We reviewed robotic cases undergoing SLN mapping with a cervical injection from January 2011 to December 2013 using either blue dye or ICG with near-infrared (NIR) fluorescence imaging. Data were stratified by body mass index (BMI) and the dye used. Appropriate statistical tests were applied.

RESULTS

Overall, 472 cases were identified. Bilateral mapping was successful in 352 cases (75 %), and unilateral mapping was successful in 73 cases (15 %). Bilateral mapping was achieved in 266 (85 %) of 312 ICG cases compared with 86 (54 %) of 160 blue-dye cases (p < 0.001). Cases with successful bilateral mapping had a median BMI of 29.8 kg/m(2) (range 16.3-65.3 kg/m(2)); cases with no mapping had a median BMI of 34.7 kg/m(2) (range 21.4-60.4 kg/m(2)) (p = 0.001). With increasing BMI, there was a significant decrease in successful bilateral mapping rates for both the ICG (p < 0.001) and blue-dye groups (p = 0.041); however, the use of ICG resulted in better bilateral (p = 0.002) and overall (p = 0.011) mapping rates compared with the use of blue dye in all BMI groups.

CONCLUSIONS

ICG results in a higher overall and bilateral SLN detection than blue dye in women with uterine cancer. Successful mapping decreases with increasing BMI irrespective of the dye used; however, it is significantly improved with the use of ICG and NIR fluorescence imaging compared with blue dye.

Virus-resembling nano-structures for near infrared fluorescence imaging of ovarian cancer HER2 receptors

Ovarian cancer remains the dominant cause of death due to malignancies of the female reproductive system. The capability to identify and remove all tumors during intraoperative procedures may ultimately reduce cancer recurrence, and lead to increased patient survival. The objective of this study is to investigate the effectiveness of an optical nano-structured system for targeted near infrared (NIR) imaging of ovarian cancer cells that over-express the human epidermal growth factor receptor 2 (HER2), an important biomarker associated with ovarian cancer. The nano-structured system is comprised of genome-depleted plant-infecting brome mosaic virus doped with NIR chromophore, indocyanine green, and functionalized at the surface by covalent attachment of monoclonal antibodies against the HER2 receptor. We use absorption and fluorescence spectroscopy, and dynamic light scattering to characterize the physical properties of the constructs. Using fluorescence imaging and flow cytometry, we demonstrate the effectiveness of these nano-structures for targeted NIR imaging of HER2 receptors in vitro. These functionalized nano-materials may provide a platform for NIR imaging of ovarian cancer.

Targeting effect of PEGylated liposomes modified with the Arg-Gly-Asp sequence on gastric cancer

Previous studies have demonstrated that the α5β1 integrin-mediated interaction with fibronectin (FN) occurs through the Arg-Gly-Asp (RGD) cell-binding sequence in repeat III10. Indocyanine green (ICG) is a near-infrared (NIR) optical dye that has been approved by the US Food and Drug Administration. In the present study, we developed an RGD-modified PEGylated liposome-encapsulated ICG (RGD-PLS-ICG) system mediated by integrin. RGD was conjugated covalently to the distal end of DSPE-PEG2000-NH2 lipid by amide binding. The characteristics and stability of the prepared liposomes were assessed. In vitro, SGC7901 cells with high expression of integrin α5β1 were selected by polymerase chain reaction (PCR) and western blotting. To confirm the targeting efficacies to gastric cancer, coumarin-6 was encapsulated as a fluorescent probe for in vitro study, and the targeting effect of RGD was detected by flow cytometry and confocal microscopy. In vivo, the bio distribution of RGD-PLS-ICG was studied by an in vivo imaging system in the tumor model. RGD-PLS-ICG and PLS-ICG had a higher UV absorbance spectrum and stability than free-ICG. Confocal microscopy and flow cytometry demonstrated that RGD-PLS-encapsulated coumarin-6 was efficiently associated with the SGC7901 cells, while limited interaction was found for the other groups. Moreover, the in vivo imaging of the liposomes indicated that RGD-PLS-ICG achieved more accumulation in the tumor tissues when compared with PLS-ICG. The significant in vitro and in vivo results suggest that RGD-PLS-ICG may be a promising fluorescent dye delivery system for targeting gastric cancer cell overexpression of integrin.

Anatomical laparoscopic hepatectomy for hepatocellular carcinoma using indocyanine green fluorescence imaging

PURPOSE

It is important to minimize surgical invasiveness in the therapy of patients with hepatocellular carcinoma (HCC), and consequently laparoscopic hepatic resection is widely performed. However, most anatomical resections, except left lateral sectionectomy, remain difficult technically, and laparoscopy-assisted procedures have been introduced as an alternative approach because of the safety and curative success of the operation. We reported previously pure laparoscopic subsegmentectomy of the liver using puncture of the portal branch under percutaneous ultrasound (US) with artificial ascites. Herein, we describe pure anatomical laparoscopic segmentectomy using the puncture method with indocyanine green (ICG) injection under laparoscopic US.

PATIENTS AND METHODS

Pure laparoscopic segmentectomy was planned for 2 patients with HCC of the liver. Identification of the segment was performed by ICG injection for optical imaging using near-infrared fluorescence under laparoscopic US guidance.

RESULTS

The procedures were completed successfully, and the postoperative courses were uneventful.

CONCLUSIONS

Pure laparoscopic segmentectomy for HCC with a conventional puncture technique by ICG injection under laparoscopic US is considered to be a useful procedure featuring both low invasiveness and curative success.

Macro- and microscopic findings of ICG fluorescence in liver tumors

Background

Reports detailing microscopic observations of indocyanine green (ICG) fluorescence imaging (IFI) in hepatocellular carcinoma (HCC) and metastatic liver cancer are rare. We were able to perform macro- and microscopic IFI results in postoperative paraffin-embedded tissue samples and formalin-fixed specimens from liver tumors.

Methods

Between April 2010 and March 2014, 19 patients with HCC or liver metastases of colorectal tumors underwent liver resection. ICG solution was injected into the peripheral vein from 14 to 2 days prior to operation. We observed liver tumor IFI during the laparotomy and IFI in resected liver sections using a photo dynamic emission (PDE) camera. The IFI of paraffin-embedded tissue samples was observed using a charge-coupled device (CCD) camera. Moreover, we microscopically performed tissue section IFI using a fluorescence microscope with an ICG-B-NQF.

Results

We performed that IFI characteristics depended on tumor type macroscopically and microscopically. In normal liver tissue, fluorescence consistent with the bile canaliculus was observed. HCC had heterogeneous IFI, forming a total or partial tumor and rim pattern. In metastatic carcinoma, we performed that non-tumor cells in the marginal region showed fluorescence and tumor cells in the central region did not fluoresce.

Conclusions

We confirmed that the variations of ICG fluorescence imaging patterns reflect different tumor characteristics in not only macroscopic imaging as previous reports but also microscopic imaging. Moreover, the ICG fluorescence method is useful for postoperative pathological detection of microscopic lesions in histopathological specimens. ICG fluorescence in paraffin-embedded tissue samples and formalin-fixed specimens is preserved in the long term.

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.

Application of fluorescence in robotic general surgery: review of the literature and state of the art

The initial use of the indocyanine green fluorescence imaging system was for sentinel lymph node biopsy in patients with breast or colorectal cancer. Since then, application of this method has received wide acceptance in various fields of surgical oncology, and it has become a valid diagnostic tool for guiding cancer treatment. It has also been employed in numerous conventional surgical procedures with much success and benefit to the patient. The advent of minimally invasive surgery brought with it a new use for fluorescence in helping to improve the safety of these procedures, particularly for single-site procedures. In 2010, a near-infrared camera was integrated into the da Vinci Si System, creating a combination of technical and minimally invasive advantages that have been embraced by several experienced surgeons. The use of fluorescence, although useful, is considered challenging. Only a few studies are currently available on the use of fluorescence in robotic general surgery, whereas many articles have focused on its application in open and laparoscopic surgery. Many of these reports describe promising and satisfactory results, although with some shortcomings. The purpose of this article is to review the current status of the use of fluorescence in general surgery and particularly its role in robotic surgery. We also review potential uses in the future.

Sentinel lymph node navigation surgery for early stage gastric cancer

We attempted to evaluate the history of sentinel node navigation surgery (SNNS), technical aspects, tracers, and clinical applications of SNNS using Infrared Ray Electronic Endoscopes (IREE) combined with Indocyanine Green (ICG). The sentinel lymph node (SLN) is defined as a first lymph node (LN) which receives cancer cells from a primary tumor. Reports on clinical application of SNNS for gastric cancers started to appear since early 2000s. Two prospective multicenter trials of SNNS for gastric cancer have also been accomplished in Japan. Kitagawa et al reported that the endoscopic dual (dye and radioisotope) tracer method for SN biopsy was confirmed acceptable and effective when applied to the early-stage gastric cancer (EGC). We have previously reported the usefulness of SNNS in gastrointestinal cancer using ICG as a tracer, combined with IREE (Olympus Optical, Tokyo, Japan) to detect SLN. LN metastasis rate of EGC is low. Hence, clinical application of SNNS for EGC might lead us to avoid unnecessary LN dissection, which could preserve the patient's quality of life after operation. The most ideal method of SNNS should allow secure and accurate detection of SLN, and real time observation of lymphatic flow during operation.

A new stage of sentinel node navigation surgery in early gastric cancer

Sentinel node (SN) navigation surgery is expected to realize organ- and function-preserving surgery with SN mapping, and has been applied in operations for breast cancer and melanoma. But there has been no definite evidence for the SN concept in gastric cancer. A prospective multicenter trial to confirm the SN concept for gastric cancer conducted by the Japan Society of Sentinel Node Navigation Surgery reported that the SN detection rate, sensitivity of positive SNs, and accuracy of nodal status are 97.5% (387/397), 93% (53/57), and 99% (383/387), respectively. A detailed analysis of the trial suggested that strictly the "lymphatic basin concept" rather than the "SN concept" was confirmed in early gastric cancer. The Japan Society of Sentinel Node Navigation Surgery started a new trial of function-preserving gastrectomy with lymphatic basin dissection (LBD) for early gastric cancer without metastasis in SNs on the basis of this promising outcome of the trial. It is supposed that LBD guarantees curability in SN navigation surgery for early gastric cancer. Full-thickness resection or endoscopic submucosal dissection in combination with laparoscopic LBD will soon be a new treatment option for early gastric cancer.

Sentinel node navigation surgery for gastric cancer: Overview and perspective

The sentinel node (SN) technique has been established for the treatment of some types of solid cancers to avoid unnecessary lymphadenectomy. If node disease were diagnosed before surgery, minimal surgery with omission of lymph node dissection would be an option for patients with early gastric cancer. Although SN biopsy has been well ascertained in the treatment of breast cancer and melanoma, SN navigation surgery (SNNS) in gastric cancer has not been yet universal due to the complicated lymphatic flow from the stomach. Satisfactory establishment of SNNS will result in the possible indication of minimally invasive surgery of gastric cancer. However, the results reported in the literature on SN biopsy in gastric cancer are widely divergent and many issues are still to be resolved, such as the collection method of SN, detection of micrometastasis in SN, and clinical benefit. The difference in the procedural technique and learning phase of surgeons is also varied the accuracy of SN mapping. In this review, we outline the current status of application for SNNS in gastric cancer.

Liposome incorporated ion sensitive in situ gels for opthalmic delivery of timolol maleate

This study was aimed to design a liposomal based ion-sensitive in situ ophthalmic delivery system of timolol maleate (TM). The TM liposome was produced by the reverse evaporation technique coupled with pH-gradients method (REVPR), and then was incorporated into deacetylated gellan gum gels. The TM liposome was demonstrated to be a round and uniform shape in TEM pictures. Compared with the TM eye drops, the TM liposome produced a 1.93 folds increase in apparent permeability coefficients (Papp), resulting in a significant increase of the corneal penetration. The TM-loaded liposome incorporated ion sensitive in situ gels (TM L-ISG) showed longer retention time on corneal surface compared with the eye drops using gamma scintigraphy technology. Draize testing showed that TM L-ISG was non-irritant for ocular tissues. The biggest efficacy of TM L-ISG occurred 30 min after eye drops administration, and efficacy disappeared after 240min. Then, compared with the eye drops, the optimal TM L-ISG could quickly reduce the intraocular pressure and the effective time was significantly longer (P≤0.05). These results indicate that liposome incorporated ion sensitive in situ gels have a potential ability for the opthalmic delivery.

Multi-channel LED light source for fluorescent agent aided minimally invasive surgery

Cancer is one of the most common and deadly diseases around the world. Amongst all the different treatments of cancer such as surgery, chemotherapy and radiation therapy, surgical resection is the most effective. Successful surgeries greatly rely on the detection of the accurate tumor size and location, which can be enhanced by contrast agents. Commercial endoscope light sources, however, offer only white light illumination. In this paper, we present the development of a LED endoscope light source that provides 2 light channels plus white light to help surgeons to detect a clear tumor margin during minimally invasive surgeries. By exciting indocyanine green (ICG) and 5-Aminolaevulinic acid (ALA)-induced protoporphyrin IX (PPIX), the light source is intended to give the user a visible image of the tumor margin. This light source is also portable, easy to use and costs less than $300 to build.

Evaluation of the novel near-infrared fluorescence tracers pullulan polymer nanogel and indocyanine green/γ-glutamic acid complex for sentinel lymph node navigation surgery in large animal models

BACKGROUND

This study aimed to examine tracers designed to overcome the disadvantages of indocyanine green (ICG), which disperses quickly to multiple lymph nodes, using a near-infrared (NIR) imaging system in animal models.

METHODS

Diluted ICG, ICG/poly-γ-glutamic acid (PGA) complex, and IRDye900-conjugated pullulan-cholesterol nanoprobe "near-infrared polynagogel" (NIR-PNG) were injected into the stomachs of dogs and pigs, and the patterns of dispersion were observed using an NIR imaging system. To compare retention times, fluorescence signals were evaluated in the stomach and small bowel of animals 1 week after injection.

RESULTS

A diluted concentration (~0.1 mg/ml) of ICG was optimal for NIR imaging compared with the conventional concentration (5 mg/ml) for visual inspection. When injected into the stomach, the signals of ICG and ICG/PGA complex were relatively large at the injection site, and signals were detected at multiple sentinel nodes and lymph nodes beyond them. The NIR-PNG signal intensity was relatively small at the injection site and limited to only one sentinel node with no additional node. When evaluated 1 week after injection, only the NIR-PNG signal was detected in the canine stomach, and the signal intensity at the lymph nodes of the porcine small bowel was the highest with NIR-PNG, followed by ICG/PGA complex and finally ICG.

CONCLUSION

NIR-PNG showed the best characteristics of less dispersion and longer retention in the sentinel nodes, and ICG/PGA complex remained longer than diluted ICG. These tracers could potentially be used as optimal tracers for sentinel node navigation surgery in gastric cancer.

Dynamic fluorescent imaging with indocyanine green for monitoring the therapeutic effects of photoimmunotherapy

A new type of monoclonal antibody (mAb)-based, highly specific phototherapy (photoimmunotherapy; PIT) that uses a near-infrared (NIR) phthalocyanine dye, IRDye700DX (IR700) conjugated with an mAb, has recently been described. NIR light exposure leads to immediate, target-selective necrotic cell death. However, tumor shrinkage takes several days to occur, making it difficult to detect earlier changes in the tumor. In this study, Panitumumab targeting the epidermal growth factor receptor (EGFR1) conjugated to IR700 was used to treat EGFR-expressing A431 tumor cells and in vivo xenografts. PIT was performed at varying doses of NIR light (10, 30, 50 and 100 J cm(-2)) in xenograft tumors in mice. Indocyanine green (ICG) dynamic imaging was evaluated for monitoring cytotoxic effects for the first hour after PIT. Our results demonstrated a statistical difference (p < 0.05) in ICG intensity between control and PIT treated tumors in the higher light exposure groups (50 J cm(-2): 2.94 ± 0.35 vs 5.22 ± 0.92, p = 0.02; and 100 J cm(-2) : 3.56 ± 0.96 vs 5.71 ± 1.43, p = 0.008) as early as 20 min post ICG injection. However, no significant difference (p > 0.05) in ICG intensity between control and PIT treated tumors was evident in the lower light exposure group at any time points up to 60 min (10 J cm(-2) : 1.92 ± 0.49 vs 1.71 ± 0.3, p = 0.44; and 30 J cm(-2): 1.57 ± 0.35 vs 2.75 ± 0.59, p = 0.07). Similarly, the retention index (background to corrected uptake ratio of ICG) varied with light exposure. In conclusion, ICG may serve as a potential indicator of acute cytotoxic effects of mAb-IR700-induced PIT even before morphological changes can be seen in targeted tumors.

Trimodal color-fluorescence-polarization endoscopy aided by a tumor selective molecular probe accurately detects flat lesions in colitis-associated cancer

Colitis-associated cancer (CAC) arises from premalignant flat lesions of the colon, which are difficult to detect with current endoscopic screening approaches. We have developed a complementary fluorescence and polarization reporting strategy that combines the unique biochemical and physical properties of dysplasia and cancer for real-time detection of these lesions. Using azoxymethane-dextran sodium sulfate (AOM-DSS) treated mice, which recapitulates human CAC and dysplasia, we show that an octapeptide labeled with a near-infrared (NIR) fluorescent dye selectively identified all precancerous and cancerous lesions. A new thermoresponsive sol-gel formulation allowed topical application of the molecular probe during endoscopy. This method yielded high contrast-to-noise ratios (CNR) between adenomatous tumors (20.6 ± 1.65) and flat lesions (12.1 ± 1.03) and surrounding uninvolved colon tissue versus CNR of inflamed tissues (1.62±0.42) Incorporation of nanowire-filtered polarization imaging into NIR fluorescence endoscopy shows a high depolarization contrast in both adenomatous tumors and flat lesions in CAC, reflecting compromised structural integrity of these tissues. Together, the real-time polarization imaging provides real-time validation of suspicious colon tissue highlighted by molecular fluorescence endoscopy.

Clinical applications of indocyanine green (ICG) enhanced fluorescence in laparoscopic surgery

Background

Recently major developments in video imaging have been achieved: among these, the use of high definition and 3D imaging systems, and more recently indocyanine green (ICG) fluorescence imaging are emerging as major contributions to intraoperative decision making during surgical procedures. The aim of this study was to present our experience with different laparoscopic procedures using ICG fluorescence imaging.

Patients and methods

108 ICG-enhanced fluorescence-guided laparoscopic procedures were performed: 52 laparoscopic cholecystectomies, 38 colorectal resections, 8 living-donor nephrectomies, 1 laparoscopic kidney autotransplantation, 3 inguino-iliac/obturator lymph node dissections for melanoma, and 6 miscellanea procedures. Visualization of structures was provided by a high definition stereoscopic camera connected to a 30° 10 mm scope equipped with a specific lens and light source emitting both visible and near infra-red (NIR) light (KARL STORZ GmbH & Co. KG, Tuttlingen, Germany). After injection of ICG, the system projected high-resolution NIR real-time images of blood flow in vessels and organs as well as highlighted biliary excretion .

Results

No intraoperataive or injection-related adverse effects were reported, and the biliary/vascular anatomy was always clearly identified. The imaging system provided invaluable information to conduct a safe cholecystectomy and ensure adequate vascular supply for colectomy, nephrectomy, or find lymph nodes. There were no bile duct injuries or anastomotic leaks.

Conclusions

In our experience, the ICG fluorescence imaging system seems to be simple, safe, and useful. The technique may well become a standard in the near future in view of its different diagnostic and oncological capabilities. Larger studies and more specific evaluations are needed to confirm its role and to address its disadvantages.

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.