Long-term follow-up after near-infrared fluorescence-guided resection of colorectal liver metastases: A retrospective multicenter analysis

A meta-analysis of the value of indocyanine green fluorescence imaging in guiding surgical resection of primary and metastatic liver cancer

OBJECTIVE

This meta-analysis aimed to evaluate the value of indocyanine green fluorescence imaging in precision resection surgery for primary and metastatic liver cancer.

METHODS

A systematic search of PubMed, Embase, Scopus, Cochrane Library, Web of Science, ScienceDirect, and major scientific websites was conducted until June 2024. Randomized controlled trials and observational studies comparing indocyanine green fluorescence imaging-guided liver cancer resection with traditional methods were included. The meta-analysis incorporated overall outcomes and subgroup outcomes based on liver cancer types (primary and metastatic). StataSE 12.0 software was used for statistical analysis after a quality assessment of the included studies.

RESULTS

Twenty studies involving 1,283 patients with liver cancer were included. The results showed that indocyanine green fluorescence imaging significantly reduced intraoperative blood loss [Weighted mean difference (WMD), -88.75; 95 % CI, -128.48 to -49.02, p < 0.05], transfusion rate [Odds ratios (OR), 0.5; 95 % CI, 0.36-0.7, p < 0.05], hospital stay duration [WMD, -1.11; 95 % CI, -1.79 to -0.43, p < 0.05], and the overall complication rate [OR, 0.59; 95 % CI, 0.44-0.79, p < 0.05]. However, no significant differences were observed in operative time or in the subgroup analysis for metastatic liver cancer.

CONCLUSION

Indocyanine green fluorescence imaging is a safe and effective intraoperative navigation technique that improves surgical outcomes and prognostic indicators in liver cancer resection. However, its efficacy in metastatic liver cancer surgery requires further validation through larger-scale, rigorous, prospective, randomized controlled trials.

Real-Time Navigation in Liver Surgery Through Indocyanine Green Fluorescence: An Updated Analysis of Worldwide Protocols and Applications

BACKGROUND

Indocyanine green (ICG) fluorescence has seen extensive application across medical and surgical fields, praised for its real-time navigation capabilities and low toxicity. Initially employed to assess liver function, ICG fluorescence is now integral to liver surgery, aiding in tumor detection, liver segmentation, and the visualization of bile leaks. This study reviews current protocols and ICG fluorescence applications in liver surgery, with a focus on optimizing timing and dosage based on clinical indications.

METHODS

Following PRISMA guidelines, we systematically reviewed the literature up to 27 January 2024, using PubMed and Medline to identify studies on ICG fluorescence used in liver surgery. A systematic review was performed to evaluate dosage and timing protocols for ICG administration.

RESULTS

Of 1093 initial articles, 140 studies, covering a total of 3739 patients, were included. The studies primarily addressed tumor detection (40%), liver segmentation (34.6%), and both (21.4%). The most common ICG fluorescence dose for tumor detection was 0.5 mg/kg, with administration occurring from days to weeks pre-surgery. Various near-infrared (NIR) camera systems were utilized, with the PINPOINT system most frequently cited. Tumor detection rates averaged 87.4%, with a 10.5% false-positive rate. Additional applications include the detection of bile leaks, lymph nodes, and vascular and biliary structures.

CONCLUSIONS

ICG fluorescence imaging has emerged as a valuable tool in liver surgery, enhancing real-time navigation and improving clinical outcomes. Standardizing protocols could further enhance ICG fluorescence efficacy and reliability, benefitting patient care in hepatic surgeries.

Efficacy and safety of indocyanine green fluorescence navigation versus conventional laparoscopic hepatectomy for hepatocellular carcinoma: a systematic review and meta-analysis

BACKGROUND

Indocyanine green (ICG) fluorescence imaging technology is increasingly widely used in laparoscopic hepatectomy. However, previous studies have produced conflicting results regarding whether it is truly superior to traditional laparoscopic hepatectomy. This study investigated the clinical effect of laparoscopic hepatectomy for hepatocellular carcinoma (HCC) using ICG imaging technology.

METHODS

A systematic review and meta-analysis, based on the preferred reporting items for systematic reviews and meta-analysis statement, were conducted (PROSPERO: CRD42024532356). A computer search was conducted in databases including CNKI, Wanfang, PubMed, Embase, Cochrane Library, and Web of Science from January 1, 1990, to April 30, 2024.

RESULTS

A total of 17 articles were included after screening, comprising 4 randomized controlled trials and 13 case-control studies, with 1620 patients in total. Among these, there were 743 cases in the fluorescence laparoscopy group and 877 cases in the non-fluorescence laparoscopy group. Hepatectomy guided by indocyanine green fluorescence navigation significantly reduced operation time (MD = - 23.25, 95% CI: - 36.35 to - 10.15, P = 0.0005), intraoperative blood loss (MD = - 51.04, 95% CI: - 69.52 to - 32.56, P < 0.00001), and intraoperative transfusion rate (OR = 0.43, 95% CI: 0.27 to 0.69, P = 0.0004), while increasing the R0 resection rate (OR = 2.93, 95% CI: 1.73 to 4.96, P < 0.0001) and decreasing the postoperative complication rate (OR = 0.59, 95% CI: 0.43 to 0.82, P = 0.002). However, there was no statistically significant difference in postoperative length of hospital stay (MD = - 0.67, 95% CI: - 1.51 to 0.18, P = 0.12).

CONCLUSION

In the treatment of HCC, hepatectomy guided by indocyanine green fluorescence navigation demonstrates superior efficacy and safety, its application and promotion are warranted.

Fluorescence-guided pancreatic surgery: A scoping review

BACKGROUND

Although fluorescence guidance during various surgical procedures has been shown to be safe and have possible better clinical outcomes than without the guidance, the use of fluorophores in pancreatic surgery is novel and not yet well described. This scoping review involved a systematic methodology of the currently available literature and aimed to illuminate the use of fluorophores in pancreatic surgery from a clinical view.

METHODS

The PRISMA and the PRISMA-ScR guidelines were used when appropriate and the following databases were searched: PubMed, Embase, Scopus, The Cochrane Collection, and Web of Science. Human original articles and case reports were included. Bias was assessed with the Newcastle-Ottawa Scale and the IDEAL framework was used for evaluation of surgical innovation.

RESULTS

A total of 5,565 search hits were screened, and 23 original articles and 24 case reports consisting of 754 patients met the inclusion criteria. The use of indocyanine green was both the most prominent and the most promising method for securing sufficient perfusion of neighboring organs, enhancing the detection and distinguishing of neuroendocrine tumors, and assisting in the identification of hepatic micrometastases.

CONCLUSION

The included studies were generally heterogenic, exploratory, and small. Indocyanine green was used in several ways, and it may add clinical value in different settings during pancreatic surgery. Tumor-targeted probes are a rapidly developing and promising field of research.

Application of indocyanine green fluorescence imaging in hepatobiliary surgery

Indocyanine green (ICG) is a fluorescent dye with an emission wavelength of about 840 nm, which is selectively absorbed by the liver after intravenous or bile duct injection, and then it is excreted into the intestines through the biliary system. With the rapid development of fluorescence laparoscopy, ICG fluorescence imaging is safe, feasible, and widely used in hepatobiliary surgery. ICG fluorescence imaging is of great significance in precise preoperative and intraoperative localization of liver lesions, real-time visualization of hepatic segmental anatomy, intrahepatic and extrahepatic biliary tract visualization, and liver transplantation. ICG fluorescence imaging facilitates efficient intraoperative hepatobiliary decision-making and improves the safety of minimally invasive hepatobiliary surgery. Advances in imaging systems will increase the use of fluorescence imaging as an intraoperative navigation tool, improving the safety and accuracy of open and laparoscopic/robotic hepatobiliary surgery. Herin, we have reviewed the status of ICG applications in hepatobiliary surgery, aiming to provide new insights for the development of hepatobiliary surgery.

Efficacy and Safety of Fluorescence-Guided Surgery Compared to Conventional Surgery in the Management of Colorectal Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

The use of fluorescence agents and imaging systems is a promising adjunct in the surgical management of colorectal cancer. This systematic review and meta-analysis aimed to assess the safety and efficacy of fluorescence-guided surgery in the management of colorectal cancer, with a comparison to conventional (non-fluorescence-guided) surgery.

METHODS

A literature search of MEDLINE, Embase, Emcare, and CINAHL databases was performed for studies that reported data on the outcomes of fluorescence-guided surgery, with or without a comparison group undergoing conventional surgery, for colorectal cancer between January 2000 and January 2024. A meta-analysis was performed using random-effect models, and between-study heterogeneity was assessed.

RESULTS

35 studies of 3217 patients with colorectal cancer were included: 26 studies (964 patients) reported on fluorescence-guided surgery and 9 studies (2253 patients) reported on fluorescence versus conventional surgery. The weighted mean of the cancer detection rate of fluorescence-guided surgery was 71% (95% CI 0.55-0.85), with no significant difference in lymph node yield ratio (WMD -0.04; 95% CI -0.10-0.02; p = 0.201) between fluorescence and conventional surgery groups. There was a significantly lower blood loss (WMD -4.38; 95% CI -7.05--1.70; p = 0.001) and complication rate (WMD -0.04; 95% CI -0.07-0.00; p = 0.027) in the fluorescence-guided surgery group, with a potentially lower anastomotic leak rate (WMD -0.05; 95% CI -0.10-0.01; p = 0.092).

CONCLUSIONS

Fluorescence-guided surgery is a safe and effective approach in the management of colorectal cancer, potentially reducing blood loss and complications. Further randomised controlled trials are required comparing fluorescence-guided surgery with conventional surgery to determine its prognostic benefit and where it should precisely fit within the management pathway of colorectal cancer.

Indocyanine Green and Hepatobiliary Surgery: An Overview of the Current Literature

Indocyanine green (ICG) is an inert polypeptide that almost totally binds to high molecular weight plasma proteins; it is cleared by the hepatocytes and directly excreted into the bile with a half-life of about 3-5 minutes. Specific systems are required to see fluorescent images. The use of this dye has been reported in different surgical specialties, and the applications in hepatobiliary surgery are widening. Being firstly used to evaluate the preoperative liver function, intra- and postoperative dynamic checking of hepatic activity has been reported and integrated within perioperative protocols allowing a tailored treatment allocation. Intravenous injection (IV) or injection into the gallbladder can ease difficult cholecystectomy. Biliary leakage detection could be enhanced by IV ICG injection. Although with some contrasting results, the use of ICG for both delineating the limits of the resection and tumor-enhanced visualization was demonstrated to improve short- and long-term outcomes. Although the lack of strong evidence still precludes the introduction of this tool in clinical practice, it harbors great potential in liver surgery.

Preclinical evaluation of EpCAM-binding designed ankyrin repeat proteins (DARPins) as targeting moieties for bimodal near-infrared fluorescence and photoacoustic imaging of cancer

PURPOSE

Fluorescence-guided surgery (FGS) can play a key role in improving radical resection rates by assisting surgeons to gain adequate visualization of malignant tissue intraoperatively. Designed ankyrin repeat proteins (DARPins) possess optimal pharmacokinetic and other properties for in vivo imaging. This study aims to evaluate the preclinical potential of epithelial cell adhesion molecule (EpCAM)-binding DARPins as targeting moieties for near-infrared fluorescence (NIRF) and photoacoustic (PA) imaging of cancer.

METHODS

EpCAM-binding DARPins Ac2, Ec4.1, and non-binding control DARPin Off7 were conjugated to IRDye 800CW and their binding efficacy was evaluated on EpCAM-positive HT-29 and EpCAM-negative COLO-320 human colon cancer cell lines. Thereafter, NIRF and PA imaging of all three conjugates were performed in HT-29_luc2 tumor-bearing mice. At 24 h post-injection, tumors and organs were resected and tracer biodistributions were analyzed.

RESULTS

Ac2-800CW and Ec4.1-800CW specifically bound to HT-29 cells, but not to COLO-320 cells. Next, 6 nmol and 24 h were established as the optimal in vivo dose and imaging time point for both DARPin tracers. At 24 h post-injection, mean tumor-to-background ratios of 2.60 ± 0.3 and 3.1 ± 0.3 were observed for Ac2-800CW and Ec4.1-800CW, respectively, allowing clear tumor delineation using the clinical Artemis NIRF imager. Biodistribution analyses in non-neoplastic tissue solely showed high fluorescence signal in the liver and kidney, which reflects the clearance of the DARPin tracers.

CONCLUSION

Our encouraging results show that EpCAM-binding DARPins are a promising class of targeting moieties for pan-carcinoma targeting, providing clear tumor delineation at 24 h post-injection. The work described provides the preclinical foundation for DARPin-based bimodal NIRF/PA imaging of cancer.

Surgical margin status outcome of intraoperative indocyanine green fluorescence-guided laparoscopic hepatectomy in liver malignancy: a systematic review and meta-analysis

BACKGROUND

Hepatectomy stands as a curative management for liver cancer. The critical factor for minimizing recurrence rate and enhancing overall survival of liver malignancy is to attain a negative margin hepatic resection. Recently, Indocyanine green (ICG) fluorescence imaging has been proven implemental in aiding laparoscopic liver resection, enabling real-time tumor identification and precise liver segmentation. The purpose of this study is to conduct a systematic review and meta-analysis to ascertain whether ICG-guided laparoscopic hepatectomy yields a higher incidence of complete tumor eradication (R0) resections.

METHODS

The search encompassed databases such as PubMed, Cochrane Library database, Scopus, ScienceDirect, and Ovid in April 2024, in strict adherence to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies involving patients with malignant liver lesions who underwent ICG-guided laparoscopic hepatectomy and reported R0 resection outcomes were eligible for inclusion in this review.

RESULTS

In a total of seven studies, involving 598 patients, were included in the meta-analysis. The ICG demonstrated a significantly elevated R0 resection rate compared to the non-ICG group [98.6% (359/364) vs. 93.1% (339/364), odds ratio (OR) = 3.76, 95% confidence intervals (CI) 1.45-9.51, P = 0.005]. Notably, no heterogeneity was observed (I2 = 0%, P = 0.5). However, the subtype analysis focusing on hepatocellular carcinoma [98.2% (165/168) vs. 93.6% (161/172), OR = 3.34, 95% CI 0.94-11.91, P = 0.06) and the evaluation of margin distance (4.96 ± 2.41 vs. 2.79 ± 1.92 millimeters, weighted mean difference = 1.26, 95% CI -1.8-4.32, P = 0.42) revealed no apparent differences. Additionally, the incidence of overall postoperative complications was comparable between both groups, 27.6% (66/239) in the ICG group and 25.4% (75/295) in the non-ICG group (OR = 0.96, 95% CI 0.53-1.76, P = 0.9). No disparities were identified in operative time, intraoperative blood loss, postoperative blood transfusion, and length of hospital stay after the surgery.

CONCLUSIONS

The implementation of ICG-guided laparoscopic hepatectomy can be undertaken with confidence, as it does not compromise either intraoperative or postoperative events. Furthermore, the ICG-guided approach is beneficial to achieving a complete eradication of the tumor during hepatic resection.

TRIAL REGISTRATION

PROSPERO registration number CRD42023446440.

ICG-Fluorescence Imaging for Margin Assessment During Minimally Invasive Colorectal Liver Metastasis Resection

Importance

Unintended tumor-positive resection margins occur frequently during minimally invasive surgery for colorectal liver metastases and potentially negatively influence oncologic outcomes.

Objective

To assess whether indocyanine green (ICG)-fluorescence-guided surgery is associated with achieving a higher radical resection rate in minimally invasive colorectal liver metastasis surgery and to assess the accuracy of ICG fluorescence for predicting the resection margin status.

Design, Setting, and Participants

The MIMIC (Minimally Invasive, Indocyanine-Guided Metastasectomy in Patients With Colorectal Liver Metastases) trial was designed as a prospective single-arm multicenter cohort study in 8 Dutch liver surgery centers. Patients were scheduled to undergo minimally invasive (laparoscopic or robot-assisted) resections of colorectal liver metastases between September 1, 2018, and June 30, 2021.

Exposures

All patients received a single intravenous bolus of 10 mg of ICG 24 hours prior to surgery. During surgery, ICG-fluorescence imaging was used as an adjunct to ultrasonography and regular laparoscopy to guide and assess the resection margin in real time. The ICG-fluorescence imaging was performed during and after liver parenchymal transection to enable real-time assessment of the tumor margin. Absence of ICG fluorescence was favorable both during transection and in the tumor bed directly after resection.

Main Outcomes and Measures

The primary outcome measure was the radical (R0) resection rate, defined by the percentage of colorectal liver metastases resected with at least a 1 mm distance between the tumor and resection plane. Secondary outcomes were the accuracy of ICG fluorescence in detecting margin-positive (R1; <1 mm margin) resections and the change in surgical management.

Results

In total, 225 patients were enrolled, of whom 201 (116 [57.7%] male; median age, 65 [IQR, 57-72] years) with 316 histologically proven colorectal liver metastases were included in the final analysis. The overall R0 resection rate was 92.4%. Re-resection of ICG-fluorescent tissue in the resection cavity was associated with a 5.0% increase in the R0 percentage (from 87.4% to 92.4%; P < .001). The sensitivity and specificity for real-time resection margin assessment were 60% and 90%, respectively (area under the receiver operating characteristic curve, 0.751; 95% CI, 0.668-0.833), with a positive predictive value of 54% and a negative predictive value of 92%. After training and proctoring of the first procedures, participating centers that were new to the technique had a comparable false-positive rate for predicting R1 resections during the first 10 procedures (odds ratio, 1.36; 95% CI, 0.44-4.24). The ICG-fluorescence imaging was associated with changes in intraoperative surgical management in 56 (27.9%) of the patients.

Conclusions and Relevance

In this multicenter prospective cohort study, ICG-fluorescence imaging was associated with an increased rate of tumor margin-negative resection and changes in surgical management in more than one-quarter of the patients. The absence of ICG fluorescence during liver parenchymal transection predicted an R0 resection with 92% accuracy. These results suggest that use of ICG fluorescence may provide real-time feedback of the tumor margin and a higher rate of complete oncologic resection.

Semi-automatic standardized analysis method to objectively evaluate near-infrared fluorescent dyes in image-guided surgery

Significance

Near-infrared fluorescence imaging still lacks a standardized, objective method to evaluate fluorescent dye efficacy in oncological surgical applications. This results in difficulties in translation between preclinical to clinical studies with fluorescent dyes and in the reproduction of results between studies, which in turn hampers further clinical translation of novel fluorescent dyes.

Aim

Our aim is to develop and evaluate a semi-automatic standardized method to objectively assess fluorescent signals in resected tissue.

Approach

A standardized imaging procedure was designed and quantitative analysis methods were developed to evaluate non-targeted and tumor-targeted fluorescent dyes. The developed analysis methods included manual selection of region of interest (ROI) on white light images, automated fluorescence signal ROI selection, and automatic quantitative image analysis. The proposed analysis method was then compared with a conventional analysis method, where fluorescence signal ROIs were manually selected on fluorescence images. Dice similarity coefficients and intraclass correlation coefficients were calculated to determine the inter- and intraobserver variabilities of the ROI selections and the determined signal- and tumor-to-background ratios.

Results

The proposed non-targeted fluorescent dyes analysis method showed statistically significantly improved variabilities after application on indocyanine green specimens. For specimens with the targeted dye SGM-101, the variability of the background ROI selection was statistically significantly improved by implementing the proposed method.

Conclusion

Semi-automatic methods for standardized quantitative analysis of fluorescence images were successfully developed and showed promising results to further improve the reproducibility and standardization of clinical studies evaluating fluorescent dyes.

Correlation Between Indocyanine Green Fluorescence Patterns and Grade of Differentiation of Hepatocellular Carcinoma: A Western Prospective Cohort Study

Background. Most of the available evidence on the use of indocyanine green (ICG) fluorescence in clinical practice consists of articles published by surgeons of the Asian-Pacific area. We performed a prospective cohort study to assess the patterns of ICG fluorescence in Western hepatocellular carcinoma (HCC) counterparts.Methods. From April 2019 to January 2022, a total of 31 consecutive patients who underwent laparoscopic liver resection (LLR) for superficial HCC were enrolled in this prospective study. All patients underwent laparoscopic staging with both laparoscopic ultrasound (LUS) and ICG fluorescence imaging.Results. A total of 38 hepatocellular carcinomas (HCCs) were enrolled: 23 superficial (surfacing at the liver's Glissonian capsule), 5 exophytic, 5 shallow (<8 mm from the hepatic surface) and 5 deep (>10 mm from the hepatic surface). The detection rate with preoperative imaging (abdominal CT/MRI), LUS, ICG fluorescence and combined modalities (ICG and LUS) was 97.4%, 94.9%, 89.7% and 100%, respectively. The five deep seated lesions underwent ultrasound-guided laparoscopic thermal ablation. The other 33 HCCs were treated with minimally invasive liver resection. Intraoperative ultrasound patterns were registered for each single nodule resected. The ICG fluorescence pattern was classified in two types: total fluorescence (all the tumoral tissue showed strong and homogeneous fluorescence), n = 9/33 (27.3%), and non-total fluorescence (partial and rim fluorescence), n = 24/33 (72.7%). There was a statistical correlation between ICG patterns and grade of differentiation. Almost all lesions with uniform fluorescence pattern were well-differentiated HCCs (G1-G2), while partial and rim-type fluorescence pattern were more common among moderately and poorly differentiated HCCs (G3-G4) (88.9% vs 11.1%, 37.5% vs 62.5%, P = .025, respectively).Conclusions. ICG fluorescence imaging could be used to identify early the grade of HCC, ie intraoperatively, thus influencing the intraoperative treatment.

Follow up after surgery for colorectal liver metastases: A systematic review

INTRODUCTION

Recurrence post hepatectomy for colorectal liver metastases (CRLM) occurs in 70 % of patients within two years. No established guidance on the method or intensity of follow-up currently exists. The aim of this systematic review was to summarise literature and determine whether it is possible to identify an optimal follow up regime. To this date there are no randomised prospective studies investigating this.

METHODS

A systematic review was performed according to PRISMA guidelines. Outcomes included general demographics, method, frequency and duration of follow up, survival and recurrence data. Quality assessment of the papers was performed.

RESULTS

Twenty-five articles published between 1994 and 2022 were included, including 9945 patients. CT was the most common imaging modality (n = 14) and CEA most common blood test (n = 11). Intensity of follow up was higher in the first two years post resection and only two papers continued follow up post 5 years resection. There was wide variation in outcome measures - Overall survival (OS) was most commonly reported. Nine papers reported OS ranging between 39 and 78.1 %.

CONCLUSIONS

There is wide variation in follow up methods and outcome reporting. There is no strong evidence to support intensive follow up, and the benefits of long term follow up are also unknown due to the lack of patient centred data. High quality, prospective studies should be the focus of future research as further retrospective data is unlikely to resolve uncertainties around optimal follow up.

High-precision detection and navigation surgery of colorectal cancer micrometastases

Surgical resection is an effective treatment for colorectal cancer (CRC) patients, whereas occult metastases hinder the curative effect. Currently, there is no effective method to achieve intraoperatively diagnosis of tumor-positive lymph nodes (LNs). Herein, we adopt a near-infrared-II (NIR-II) organic donor-pi-acceptor-pi-donor probe FE-2PEG, which exhibits bright fluorescence over 1100 nm, excellent photostability, blood circulation time, and biocompatibility, to achieve high-performance bioimaging with improved temporal and spatial resolution. Importantly, the FE-2PEG shows efficient passive enrichment in orthotopic CRC, metastatic mesenteric LNs, and peritoneal metastases by enhanced permeability and retention effect. Under NIR-II fluorescence-guided surgery (FGS), the peritoneal micrometastases were resected with a sensitivity of 94.51%, specificity of 86.59%, positive predictive value (PPV) of 96.57%, and negative predictive value of 79.78%. The PPV still achieves 96.07% even for micrometastases less than 3 mm. Pathological staining and NIR-II microscopy imaging proved that FE-2PEG could successfully delineate the boundary between the tumor and normal tissues. Dual-color NIR-II imaging strategy with FE-2PEG (1100 ~ 1300 nm) and PbS@CdS quantum dots (> 1500 nm) successfully protects both blood supply and normal tissues during surgery. The NIR-II-based FGS provides a promising prospect for precise intraoperative diagnosis and minimally invasive surgery of CRC.

Use of Near-Infrared Fluorescence Techniques in Minimally Invasive Surgery for Colorectal Liver Metastases

Colorectal liver metastases (CRLM) afflict a significant proportion of patients with colorectal cancer (CRC), ranging from 25% to 30% of patients throughout the course of the disease. In recent years, there has been a surge of interest in the application of near-infrared fluorescence (NIRF) imaging as an intraoperative imaging technique for liver surgery. The utilisation of NIRF-guided liver surgery, facilitated by the administration of fluorescent dye indocyanine green (ICG), has gained traction in numerous medical institutions worldwide. This innovative approach aims to enhance lesion differentiation and provide valuable guidance for surgical margins. The use of ICG, particularly in minimally invasive surgery, has the potential to improve lesion detection rates, increase the likelihood of achieving R0 resection, and enable anatomically guided resections. However, it is important to acknowledge the limitations of ICG, such as its low specificity. Consequently, there has been a growing demand for the development of tumour-specific fluorescent probes and the advancement of camera systems, which are expected to address these concerns and further refine the accuracy and reliability of intraoperative fluorescence imaging in liver surgery. While NIRF imaging has been extensively studied in patients with CRLM, it is worth noting that a significant proportion of published research has predominantly focused on the detection of hepatocellular carcinoma (HCC). In this study, we present a comprehensive literature review of the existing literature pertaining to intraoperative fluorescence imaging in minimally invasive surgery for CRLM. Moreover, our analysis places specific emphasis on the techniques employed in liver resection using ICG, with a focus on tumour detection in minimal invasive surgery (MIS). Additionally, we delve into recent developments in this field and offer insights into future perspectives for further advancements.

Application of indocyanine green-mediated fluorescence molecular imaging technology in liver tumors resection: a systematic review and meta-analysis

Background

This meta-analysis was dedicated to evaluating the safety and effectiveness of indocyanine green (ICG) -mediated fluorescence molecular imaging (FMI) technology in liver tumors resection.

Methods

A literature search of PubMed, Embase databases, Cochrane Library, and Web of Science was performed to identify all clinical controlled studies exploring the effects of fluorescence imaging on liver tumors resection. Quality assessment and data extraction of studies were conducted independently by 3 reviewers. Mean difference (MD) and odds ratio (OR) with 95% confidence interval (CI) were calculated using a fixed-effects or random-effects model. The meta-analysis was performed with RevMan 5.3 software.

Results

14 retrospective cohort studies (RCSs) involving a total of 1227 patients were finally included. The results showed that Fluorescence-assisted liver tumors resection could improve the R0 resection rate (OR = 2.63; 95% CI: 1.46~4.73, p = 0.001), reduce overall complications (OR = 0.66; 95% CI: 0.44~0.97, p = 0.04), biliary fistula (OR = 0.20; 95% CI: 0.05~0.77, p = 0.02), intraoperative blood loss (MD = -70.76, 95% CI: -106.11 to -35.41; p < 0.0001), and shortens hospital stay (MD = -1.41, 95% CI: -1.90 to -0.92; p < 0.00001). There were no significant differences in the incidences of operative time (MD = -8.68, 95% CI: -18.59 to -1.22; p = 0.09), complications of grade III or above (OR = 0.73; 95% CI: 0.43~1.25, p = 0.26), liver failure (OR = 0.86; 95% CI: 0.39~1.89, p = 0.71), and blood transfusion (OR = 0.66; 95% CI: 0.42~1.03, p = 0.07).

Conclusion

Current evidence suggests that ICG-mediated FMI technology could enhance the clinical effectiveness of patients with liver tumors resection and is clinically worthy of promotion.

Systematic review registration

PROSPERO, identifier CRD42022368387.

Safety and effectiveness of fluorescence laparoscopy in precise hepatectomy: A meta-analysis

BACKGROUND

To perform a systematic review of the safety and effectiveness of fluorescence laparoscopy-guided precise hepatectomy.

METHODS

We searched the PubMed, Embase, Web of Science, and Cochrane Library databases from inception to December 1, 2022, using the search terms "indocyanine green," "ICG," "infracyanine green," "laparoscopy," "liver resection," and "hepatectomy." After performing a methodological quality assessment of the included studies, the overall results were subjected to meta-analysis using Review Manager 5.3.

RESULTS

After screening, the meta-analysis included a total of 13 articles. The studies included 1,115 patients who were grouped into the fluorescence laparoscopy (490 patients) and conventional laparoscopy (625 patients) groups. All articles included in the meta-analysis were of high quality. The results of the meta-analysis revealed that compared to the conventional laparoscopy group, the fluorescence laparoscopy group had a higher R0 resection rate (odds ratio=4.03, 95% confidence interval [1.50, 10.83], P = 0.006), lower blood transfusion rate (odds ratio=0.46, 95% confidence interval [0.21, 0.97], P = 0.04) and lower blood loss (mean difference=-36.58; 95% confidence interval [-59.75, -13.41], P = 0.002). However, the length of hospital stay, operative time, and incidence of postoperative complications did not differ significantly between both groups (P>0.05).

CONCLUSION

Compared to conventional laparoscopy, fluorescence laparoscopy provides better application effects in hepatectomy. The surgical procedure has demonstrated good safety and feasibility, which make it worthy of popularization.

Early results of minimally invasive fluorescent guided pediatric oncology surgery with delivery of indocyanine green during induction of anesthesia

BACKGROUND

Indocyanine green (ICG) fluoresces in the near infra-red (NIR) spectrum. It is widely used in adult oncological surgery for identification of tumor margins and lymph node sampling. However, deliver of ICG in almost all studies is 24 h or more prior to surgery. This is the first study in children to assess its feasibility in minimally invasive surgery (MIS) for oncological disease following ICG injection during induction of anesthesia.

METHODS

This was an open label, prospective, single center, feasibility study recruiting consecutive patients eligible for MIS tumor resection or metastectomy. ICG was injected intravenously at induction of anesthesia. Patient demographics, intraoperative appearances, post-operative histopathology, and surgeon Likert ratings were collected.

RESULTS

Fourteen patients were included. Five had lung metastases (Wilms, Osteosarcoma (2), Hodgkin's, melanoma) and 9 had other tumors (neuroblastoma, inflammatory myofibroblastic tumor, ganglioneuroma, phaeochromocytoma, adrenal tumor). Lung metastases were easily identifiable, and all had negative margins. Tumors containing viable disease fluoresced and were completely resected, whilst benign and heavily treated tumors were afluorescent. There were no adverse events relating to ICG or issues with background fluorescence.

CONCLUSION

Based on this small sample, injection of ICG during induction of anesthesia is safe and effective in showing tumor margins in patients who have had little or no neoadjuvant chemotherapy as well as in metastectomy in Wilms and osteosarcoma. Further studies are needed to confirm these preliminary results.

Detection of Colorectal Liver Metastases Using Near-Infrared Fluorescence Imaging During Hepatectomy: Prospective Single Centre UK Study

INTRODUCTION

Small superficial colorectal liver metastases (CLM) may be difficult to localise intraoperatively, especially during minimally invasive hepatectomy due to reduced tactile feedback and limitations of ultrasound (US). Near-infrared (NIRF) fluorescence imaging is an emerging technology that permits detection of liver tumours after systemic injection of indocyanine green (ICG). Our aim was to report our experience using NIRF to detect CLM.

PATIENTS AND METHODS

Patients with small, superficial resectable CLM received a 10-mg IV bolus of ICG the day before hepatectomy. All patients underwent preoperative liver-specific MRI. CLM were localised intraoperatively using a combination of white light/ultrasound (WL-US) and NIRF. Sensitivity and specificity of NIRF were compared with WL-US.

RESULTS

Between March 2019 and July 2021, NIRF was utilised in 15 patients who underwent hepatectomy (laparoscopic 13, open 2). Thirty-two lesions were detected by MRI (including 3 disappearing CLM), of which 2 were ICG-negative and not resected (1 haemangioma, 1 disappearing CLM). Of 30 resected lesions, the median tumour diameter was 11 mm (range 2-25), median distance from liver surface was 4.5 mm (range 0-20) and all were confirmed CLM on histology (R0 resection rate 71%). Twenty-three of thirty (77%) and twenty-seven of thirty (90%) resected CLM were detected by WL-US and NIRF, respectively. Of 7/30 (23%) resected CLM that were WL-US negative, 5 were ICG-positive. Two resected 'disappearing' CLM were ICG-positive, one of which contained viable cancer cells. Overall, NIRF influenced the operative strategy in 6 patients (43%).

CONCLUSION

Near-infrared fluorescence imaging allows detection of small, superficial colorectal liver metastases that are missed by conventional techniques and warrants further study.

The Value of Indocyanine Green Image-Guided Surgery in Patients with Primary Liver Tumors and Liver Metastases

INTRODUCTION

Successful R0 resection is crucial for the survival of patients with primary liver cancer (PLC) or liver metastases. Up to date, surgical resection lacks a sensitive, real-time intraoperative imaging modality to determine R0 resection. Real-time intraoperative visualization with near-infrared light fluorescence (NIRF) using indocyanine green (ICG) may have the potential to meet this demand. This study evaluates the value of ICG visualization in PLC and liver metastases surgery regarding R0 resection rates.

MATERIALS AND METHODS

Patients with PLC or liver metastases were included in this prospective cohort study. ICG 10 mg was administered intravenously 24 h before surgery. Real-time intraoperative NIRF visualization was created with the Spectrum^TM fluorescence imaging camera system. First, all liver segments were inspected with the fluorescence imaging system and intraoperative ultrasound for identification of the known tumor, as well as additional lesions, and were compared to preoperative MRI images. PLC, liver metastases, and additional lesions were then resected according to oncological principles. In all resected specimens, the resection margins were analyzed with the fluorescence imaging system for ICG-positive spots immediately after resection. Histology of additional detected lesions, as well as ICG fluorescence compared to histological resection margins, were assessed.

RESULTS

Of the 66 included patients, median age was 65.5 years (IQR 58.7-73.9), 27 (40.9%) were female, and 18 (27.3%) were operated on laparoscopically. Additional ICG-positive lesions were detected in 23 (35.4%) patients, of which 9 (29%) were malignant. In patients with no fluorescent signal at the resection margin, R0 rate was 93.9%, R1 rate was 6.1%, and R2 rate was 0% compared to an ICG-positive resection margin with an R0 rate of 64.3%, R1 rate of 21.4%, and R2 rate of 14.3% (p = 0.005). One- and two-year overall survival rates were 95.2% and 88.4%, respectively.

CONCLUSION

The presented study provides significant evidence that ICG NIRF guidance helps to identify R0 resection intraoperatively. This offers true potential to verify radical resection and improve patient outcomes. Furthermore, implementation of NIRF-guided imaging in liver tumor surgery allows us to detect a considerable amount of additional malignant lesions.

A meta-analysis of short-term and long-term effects of indocyanine green fluorescence imaging in hepatectomy for liver cancer

OBJECTIVES

This meta-analysis aimed to compare the short-term and long-term effects of indocyanine green fluorescence imaging in hepatectomy for liver cancer.

METHODS

The databases PubMed, Embase, Scopus, Cochrane Library, Web of Science, ScienceDirect, and major scientific websites were screened up to January 2023. Randomized controlled trials and observational studies comparing fluorescence navigation-assisted and fluorescence-free navigation-assisted hepatectomy for liver cancer were included. Our meta-analysis comprises overall results and 2 subgroup analyses based on surgery type (laparoscopy and laparotomy). These estimates are presented as mean differences (MD) or odds ratio (OR) estimates with 95% CIs.

RESULTS

We analyzed 16 studies that included 1260 patients with liver cancer. Our results showed that fluorescent navigation-assisted hepatectomy were significantly more shorter than fluorescence-free navigation-assisted hepatectomy in the following parameters: operative time [MD = -16.19; 95% CI: -32.27 to -0.11; p = 0.050], blood loss [MD = -107.90; 95% CI: -160.46 to -55.35; p < 0.001], blood transfusion [OR = 0.5; 95% CI: 0.35 to 0.72; p = 0.0002], hospital stay [MD = -1.60; 95% CI: -2.33 to -0.87; p < 0.001], and postoperative complications [OR = 0.59; 95% CI: 0.42 to 0.82; p = 0.002], The one-year disease-free survival rate [OR = 2.87; 95% CI: 1.64 to 5.02; p = 0.0002] was higher in the fluorescent navigation-assisted hepatectomy group.

CONCLUSIONS

Indocyanine green fluorescence imaging has good clinical value and can improve the short-term and long-term results of hepatectomy for liver cancer.

European Association for Endoscopic Surgery (EAES) consensus on Indocyanine Green (ICG) fluorescence-guided surgery

BACKGROUND

In recent years, the use of Indocyanine Green (ICG) fluorescence-guided surgery during open and laparoscopic procedures has exponentially expanded across various clinical settings. The European Association of Endoscopic Surgery (EAES) initiated a consensus development conference on this topic with the aim of creating evidence-based statements and recommendations for the surgical community.

METHODS

An expert panel of surgeons has been selected and invited to participate to this project. Systematic reviews of the PubMed, Embase and Cochrane libraries were performed to identify evidence on potential benefits of ICG fluorescence-guided surgery on clinical practice and patient outcomes. Statements and recommendations were prepared and unanimously agreed by the panel; they were then submitted to all EAES members through a two-rounds online survey and results presented at the EAES annual congress, Barcelona, November 2021.

RESULTS

A total of 18,273 abstracts were screened with 117 articles included. 22 statements and 16 recommendations were generated and approved. In some areas, such as the use of ICG fluorescence-guided surgery during laparoscopic cholecystectomy, the perfusion assessment in colorectal surgery and the search for the sentinel lymph nodes in gynaecological malignancies, the large number of evidences in literature has allowed us to strongly recommend the use of ICG for a better anatomical definition and a reduction in post-operative complications.

CONCLUSIONS

Overall, from the systematic literature review performed by the experts panel and the survey extended to all EAES members, ICG fluorescence-guided surgery could be considered a safe and effective technology. Future robust clinical research is required to specifically validate multiple organ-specific applications and the potential benefits of this technique on clinical outcomes.

[Indocyanine green in liver tumor resection]

Primary liver cancer and colorectal cancer liver metastases are among the leading causes of cancer-related mortality worldwide. Surgery is one of the main methods of treatment to achieve the best results in overall and recurrence-free survival. The main objectives in this surgery are preoperative planning, assessment of functional viability of liver parenchyma and total resection with low complication rate. Post-resection liver failure is one of the most formidable and often fatal complication following functional failure of liver remnant. Thus, preoperative assessment of liver functional reserves is a necessary step for adequate selection of patients and safe surgery. Passive liver tests, such as biochemical parameters or clinical scales, do not accurately reflect the actual functional component of liver parenchyma. The most accurate method is dynamic quantitative test of liver, such as indocyanine green clearance. The authors discuss the practical aspects of preoperative assessment of liver functional reserves using indocyanine green, as well as the concept and technical foundations of fluorescent imaging in hepatobiliary surgery.

Indocyanine Green Fluorescence-Guided Surgery for Gastrointestinal Tumors: A Systematic Review

Objective

To conduct a systematic review of the currently available literature on the use of ICG to guide surgical dissection in gastrointestinal (GI) cancer surgery.

Background

Real-time indocyanine green (ICG) fluorescence-guided surgery has the potential to enhance surgical outcomes by increasing patient-tailored oncological precision.

Methods

MEDLINE, PubMed, EMBASE, and Google Scholar were searched for publications on the use of ICG as a contrast agent in GI cancer surgery until December 2020. Perfusion studies were excluded. Quality of the studies was assessed with the Methodological Index for nonrandomized Studies or Jadad scale for randomized controlled trials. A narrative synthesis of the results was provided, with descriptive statistics when appropriate.

Results

Seventy-eight studies were included. ICG was used for primary tumor and metastases localization, for sentinel lymph node detection, and for lymph flow mapping. The detection rate for primary colorectal and gastric tumors was 100% after preoperative ICG endoscopic injection. For liver lesions, the detection rate after intravenous ICG infusion was 80% and up to 100% for lesions less than 8 mm from the liver surface. The detection rate for sentinel lymph nodes was 89.8% for esophageal, 98.6% for gastric, 87.4% for colorectal, and 83.3% for anal tumors, respectively. In comparative studies, ICG significantly increases the quality of D2 lymphadenectomy in oncological gastrectomy.

Conclusion

The use of ICG as a guiding tool for dissection in GI surgery is promising. Further evidence from high-quality studies on larger sample sizes is needed to assess whether ICG-guided surgery may become standard of care.

The Role of ICG in Robot-Assisted Liver Resections

Introduction: Robotic-assisted liver surgery (RALS) with its known limitations is gaining more importance. The fluorescent dye, indocyanine green (ICG), is a way to overcome some of these limitations. It accumulates in or around hepatic masses. The integrated near-infrared cameras help to visualize this accumulation. We aimed to compare the influence of ICG staining on the surgical and oncological outcomes in patients undergoing RALS. Material and Methods: Patients who underwent RALS between 2014 and 2021 at the Department of General Surgery at the University Hospital Schleswig-Holstein, Campus Kiel, were included. In 2019, ICG-supported RALS was introduced. Results: Fifty-four patients were included, with twenty-eight patients (50.9%) receiving preoperative ICG. Hepatocellular carcinoma (32.1%) was the main entity resected, followed by the metastasis of colorectal cancers (17%) and focal nodular hyperplasia (15.1%). ICG staining worked for different tumor entities, but diffuse staining was noted in patients with liver cirrhosis. However, ICG-supported RALS lasted shorter (142.7 ± 61.8 min vs. 246.4 ± 98.6 min, p < 0.001), tumors resected in the ICG cohort were significantly smaller (27.1 ± 25.0 mm vs. 47.6 ± 35.2 mm, p = 0.021) and more R0 resections were achieved by ICG-supported RALS (96.3% vs. 80.8%, p = 0.075). Conclusions: ICG-supported RALS achieve surgically and oncologically safe results, while overcoming the limitations of RALS.

Indocyanine Green Fluorescence Navigation in Liver Surgery: A Systematic Review on Dose and Timing of Administration

BACKGROUND

Indocyanine green (ICG) fluorescence has proven to be a high potential navigation tool during liver surgery; however, its optimal usage is still far from being standardized.

METHODS

A systematic review was conducted on MEDLINE/PubMed for English articles that contained the information of dose and timing of ICG administration until February 2021. Successful rates of tumor detection and liver segmentation, as well as tumor/patient background and imaging settings were also reviewed. The quality assessment of the articles was performed in accordance with the Scottish Intercollegiate Guidelines Network (SIGN).

RESULTS

Out of initial 311 articles, a total of 72 manuscripts were obtained. The quality assessment of the included studies revealed usually low; only 9 articles got qualified as high quality. Forty articles (55%) focused on open resections, whereas 32 articles (45%) on laparoscopic and robotic liver resections. Thirty-four articles (47%) described tumor detection ability, and 25 articles (35%) did liver segmentation ability, and the others (18%) did both abilities. Negative staining was reported (42%) more than positive staining (32%). For tumor detection, majority used the dose of 0.5 mg/kg within 14 days before the operation day, and an additional administration (0.02-0.5 mg/kg) in case of longer preoperative interval. Tumor detection rate was reported to be 87.4% (range, 43%-100%) with false positive rate reported to be 10.5% (range, 0%-31.3%). For negative staining method, the majority used 2.5 mg/body, ranging from 0.025 to 25 mg/body. For positive staining method, the majority used 0.25 mg/body, ranging from 0.025 to 12.5 mg/body. Successful segmentation rate was 88.0% (range, 53%-100%).

CONCLUSION

The time point and dose of ICG administration strongly needs to be tailored case by case in daily practice, due to various tumor/patient backgrounds and imaging settings.

The complementary value of intraoperative fluorescence imaging and Raman spectroscopy for cancer surgery: combining the incompatibles

A clear margin is an important prognostic factor for most solid tumours treated by surgery. Intraoperative fluorescence imaging using exogenous tumour-specific fluorescent agents has shown particular benefit in improving complete resection of tumour tissue. However, signal processing for fluorescence imaging is complex, and fluorescence signal intensity does not always perfectly correlate with tumour location. Raman spectroscopy has the capacity to accurately differentiate between malignant and healthy tissue based on their molecular composition. In Raman spectroscopy, specificity is uniquely high, but signal intensity is weak and Raman measurements are mainly performed in a point-wise manner on microscopic tissue volumes, making whole-field assessment temporally unfeasible. In this review, we describe the state-of-the-art of both optical techniques, paying special attention to the combined intraoperative application of fluorescence imaging and Raman spectroscopy in current clinical research. We demonstrate how these techniques are complementary and address the technical challenges that have traditionally led them to be considered mutually exclusive for clinical implementation. Finally, we present a novel strategy that exploits the optimal characteristics of both modalities to facilitate resection with clear surgical margins.

Integration of Three-Dimensional Liver Models in a Multimodal Image-Guided Robotic Liver Surgery Cockpit

Background: Robotic liver surgery represents the most recent evolution in the field of minimally-invasive liver surgery. For planning and guidance of liver resections, surgeons currently rely on preoperative 2-dimensional (2D) CT and/or MR imaging and intraoperative ultrasonography. Translating 2D images into digital 3-dimensional (3D) models may improve both preoperative planning and surgical guidance. The da Vinci^® robotic surgical system is a platform suitable for the integration of multiple imaging modalities into one single view. In this study, we describe multimodal imaging options and introduce the Robotic Liver Surgery Cockpit; Methods: in-house developed software was used and validated for segmentation and registration to create a virtual reality 3D model of the liver based on preoperative imaging. The accuracy of the 3D models in the clinical setting was objectively assessed in 15 patients by measuring tumor diameters and subjectively with a postoperative conducted questionnaire; Results: Implementation and applicability of the 3D model in the surgical cockpit was feasible in all patients and the quality of the 3D reconstructions was high in 14 (93%) of cases. Tumor diameters measured on CT and/or MR imaging were comparable to automated measurements using the segmentation software and 3D models; Conclusions: the 3D model was successfully incorporated in the robotic surgery console as part of a multimodality imaging platform and aided the surgeon in planning and guidance of the resection. Future studies should focus on further automation of 3D rendering and progress into augmented reality.

Role of Indocyanine Green Fluorescence Imaging in Minimally Invasive Resection of Colorectal Liver Metastases

Indocyanine green (ICG) fluorescence imaging is an easy and reproducible method to detect hepatic lesions, both primary and metastatic. This review reports the potential benefits of this technique as a tactile mimicking visual tool and a navigator guide in minimally invasive liver resection of colorectal liver metastases (CRLM). PubMed and MEDLINE databases were searched for studies reporting the use of intravenous injection of ICG before minimally invasive surgery for CLRM. The search was performed for publications reported from the first study in 2014 to April 2021. The final review included 13 articles: 6 prospective cohort studies, 1 retrospective cohort study, 3 case series, 1 case report, 1 case-matched study, and 1 clinical trial registry. The administered dose ranged between 0.3 and 0.5 mg/kg, while timing ranged between 1 and 14 days before surgery. CRLM detection rate ranged between 30.3% and 100% with preoperative imaging (abdominal computed tomography/magnetic resonance imaging), between 93.3 and 100% with laparoscopic ultrasound, between 57.6% and 100% with ICG fluorescence, and was 100% with combined modalities (ICG and laparoscopic ultrasound) with weighted averages of 77.42%, 95.97%, 79.03%, and 100%, respectively. ICG fusion imaging also allowed to detect occult small-sized lesions, not diagnosed preoperatively. In addition, ICG is effective in real-time assessment of surgical margins by evaluating the integrity of the fluorescent rim around the CRLM.

Efficacy of Near-Infrared Fluorescence-Guided Hepatectomy for the Detection of Colorectal Liver Metastases: A Randomized Controlled Trial

BACKGROUND

The application of indocyanine green fluorescence-guided hepatectomy for liver metastases from colorectal cancer is in the preliminary stage of clinical practice; thus, its efficacy needs to be determined. This study compared the number of intrahepatic colorectal liver metastases detected intraoperatively and postoperative recovery data between patients who underwent traditional hepatectomy (nonindocyanine green group) and traditional hepatectomy plus intraoperative indocyanine green fluorescence imaging (indocyanine green group).

STUDY DESIGN

Between January 2018 and March 2020, patients with potentially resectable colorectal liver metastases were randomly assigned to the nonindocyanine green or indocyanine green group. The number of intrahepatic colorectal liver metastases identified intraoperatively and based on postoperative recovery data were compared between both groups.

RESULTS

Overall, we recruited 80 patients, among whom 72 eligible patients were randomly assigned. After allocation, 64 patients, comprising 32 in each group, underwent the allocated intervention and follow-up. Compared with the nonindocyanine green group, the mean number of intrahepatic colorectal liver metastases identified intraoperatively in the indocyanine green group was significantly greater (mean [standard deviation], 3.03 [1.58] vs 2.28 [1.35]; p = 0.045), the postoperative hospital stay was shorter (p = 0.012) and the 1-year recurrence rate was also lower (p = 0.017). Postoperative complications and 90-day mortality were comparable, with no statistical differences.

CONCLUSIONS

Indocyanine green fluorescence imaging significantly increases the number of intrahepatic colorectal liver metastases identified and reduces postoperative hospital stay and 1-year recurrence rate without increasing hepatectomy-related complications and mortality rates.

Emerging Technologies for the Detection of Cancer Micrometastasis

The most efficient way to treat tumors is through surgery. However, many cancer patients have a poor prognosis even when they undergo radical excision at an early stage. Micrometastasis is one of the most critical factors that induced this situation. Undetected micrometastasis can lead to the failure of initial treatment. Therefore, preoperative and intraoperative detection of micrometastasis could have a significant clinical influence on the prognosis and optimal therapy for cancer patients. Additionally, to achieve this goal, researchers have aimed to create more effective detection technologies. Herein, we classify the currently reported micrometastasis detection technologies, introduce some representative samples for each technology, including the limitations, and provide future directions to overcome the limitations.

Augmented Reality and Image-Guided Robotic Liver Surgery

Artificial intelligence makes surgical resection easier and safer, and, at the same time, can improve oncological results. The robotic system fits perfectly with these more or less diffused technologies, and it seems that this benefit is mutual. In liver surgery, robotic systems help surgeons to localize tumors and improve surgical results with well-defined preoperative planning or increased intraoperative detection. Furthermore, they can balance the absence of tactile feedback and help recognize intrahepatic biliary or vascular structures during parenchymal transection. Some of these systems are well known and are already widely diffused in open and laparoscopic hepatectomies, such as indocyanine green fluorescence or ultrasound-guided resections, whereas other tools, such as Augmented Reality, are far from being standardized because of the high complexity and elevated costs. In this paper, we review all the experiences in the literature on the use of artificial intelligence systems in robotic liver resections, describing all their practical applications and their weaknesses.

Fluorescence-guided surgery in colorectal cancer; A review on clinical results and future perspectives

BACKGROUND

Colorectal cancer is the fourth most diagnosed malignancy worldwide and surgery is one of the cornerstones of the treatment strategy. Near-infrared (NIR) fluorescence imaging is a new and upcoming technique, which uses an NIR fluorescent agent combined with a specialised camera that can detect light in the NIR range. It aims for more precise surgery with improved oncological outcomes and a reduction in complications by improving discrimination between different structures.

METHODS

A systematic search was conducted in the Embase, Medline and Cochrane databases with search terms corresponding to 'fluorescence-guided surgery', 'colorectal surgery', and 'colorectal cancer' to identify all relevant trials.

RESULTS

The following clinical applications of fluorescence guided surgery for colorectal cancer were identified and discussed: (1) tumour imaging, (2) sentinel lymph node imaging, (3) imaging of distant metastases, (4) imaging of vital structures, (5) imaging of perfusion. Both experimental and FDA/EMA approved fluorescent agents are debated. Furthermore, promising future modalities are discussed.

CONCLUSION

Fluorescence-guided surgery for colorectal cancer is a rapidly evolving field. The first studies show additional value of this technique regarding change in surgical management. Future trials should focus on patient related outcomes such as complication rates, disease free survival, and overall survival.

Tumor visualization and fluorescence angiography with indocyanine green (ICG) in laparoscopic and robotic hepatobiliary surgery - valuation of early adopters from Germany

Objectives

Indocyanine green (ICG) is a fluorescent dye which was initially used for liver functional assessment. Moreover, it is of value for intraoperative visualization of liver segments and bile ducts or primary and secondary liver tumors. Especially in minimally invasive liver surgery, this is essential to enhance the precision of anatomical guided surgery and oncological quality. As early adopters of ICG implementation into laparoscopic and robotic-assisted liver surgery in Germany, we summarize the current recommendations and share our experiences.

Methods

Actual strategies for ICG application in minimally invasive liver surgery were evaluated and summarized during a review of the literature. Experiences in patients who underwent laparoscopic or robotic-assisted liver surgery with intraoperative ICG staining between 2018 and 2020 from the Magdeburg registry for minimally invasive liver surgery (MD-MILS) were evaluated and the data were analyzed retrospectively.

Results

ICG can be used to identify anatomical liver segments by fluorescence angiography via direct or indirect tissue staining. Fluorescence cholangiography visualizes the intra- and extrahepatic bile ducts. Primary and secondary liver tumors can be identified with a sensitivity of 69-100%. For this 0.5 mg/kg body weight ICG must be applicated intravenously 2-14 days prior to surgery. Within the MD-MILS we identified 18 patients which received ICG for intraoperative tumor staining of hepatocellular carcinoma (HCC), cholangiocarcinoma, peritoneal HCC metastases, adenoma, or colorectal liver metastases. The sensitivity for tumor staining was 100%. In 27.8% additional liver tumors were identified by ICG fluorescence. In 39% a false positive signal could be detected. This occurred mainly in cirrhotic livers.

Conclusions

ICG staining is a simple and useful tool to assess individual hepatic anatomy or to detect tumors during minimally invasive liver surgery. It may enhance surgical precision and improve oncological quality. False-positive detection rates of liver tumors can be reduced by respecting the tumor entity and liver functional impairments.

Does application of indocyanine green fluorescence imaging enhance clinical outcomes in liver resection? A meta-analysis

BACKGROUND

Indocyanine green fluorescence imaging technology has been widely used in liver resection. However, there has been a lack of strong evidence on whether application of indocyanine green fluorescence imaging enhances clinical outcomes in liver resection. This meta-analysis was performed to compare the latest clinical results of indocyanine green fluorescence imaging-guided hepatectomy (FIGH) and conventional hepatectomy (CH) in liver diseases.

METHODS

Relevant clinical studies were retrieved from PubMed, Embase, Cochrane Library, Medline and the Web of Science databases until June 21, 2021. Stata14.0 software was adopted in meta-analysis, in which the pooled effect size was calculated by the random-effects model or the fixed-effects model. Meta-regression and subgroup analysis were used to explore sources of heterogeneity. The publication bias was ascertained by egger's test and begg's test. The trim and fill method was used to adjust the occurrence of publication bias.

RESULTS

Overall twelve studies comprising 931 patients were included. Compared to the CH group, the FIGH group has lower complications (weighted mean difference [WMD] = 0.5238; 95% CI = 0.351-0.780; P = 0.001), shorter hospital stays (WMD = -1.857; 95% CI = -2.806--0.908; P = 0.000). Six of the studies indicated that no perioperative mortality occurred in either group. In overall analysis, there was no statistical difference in the estimated blood loss between the two groups (WMD = -42.509; 95% CI = -87.842 -2.825; P = 0.066), while in subgroup analysis of only literature from Japan or published between 2018 and 2019 years showed the consistent results above (WMD = 5.613; 95% CI = -45.101-56.328; P = 0.828. WMD = 5.582; 95% CI = -34.597-45.762; P = 0.785). No significant differences were found in operative time, blood transfusion rate, R0 resection, 1-year recurrence rate, 2-year-recurrence rate and the 1-year overall survival rate (P > 0.05).

CONCLUSION

This meta-analysis showed that during the liver resection operation, application of indocyanine green fluorescence imaging is a feasible and safe method in the treatment of liver diseases, which enhances some clinical outcomes, such as lower complications and shorter hospital stays.

Consensus Guidelines for the Use of Fluorescence Imaging in Hepatobiliary Surgery

OBJECTIVE

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Intraoperative indocyanine green-visualization in a difficult to localize central cholangiocarcinoma - A case report

INTRODUCTION AND IMPORTANCE

Near infrared fluorescence imaging with indocyanine green (ICG) can facilitate the intraoperative tumour localization and therefore a complete resection. Cholangiocarcinoma is an aggressive tumour and complete resection improves the outcome. Therefore, it is necessary to localize the tumour exactly but the translation of the preoperative imaging into the intraoperative setting can be difficult based only on sonography, computed tomography or magnetic resonance imaging. CASE PRESENTATION/CLINICAL FINDINGS AND INVESTIGATIONS/INTERVENTIONS AND OUTCOME: In this case a hepatic lesion suspicious for cholangiocarcinoma was discovered accidentally. Further diagnostics were unable to prove the diagnosis, therefore right hepatectomy was recommended and performed. Preoperatively ICG was administered and near infrared imaging was used intraoperatively clearly localizing the tumour, thus facilitating the resection. The intra- and postoperative course was uneventful.

RELEVANCE AND IMPACT

This case report supports the very promising intraoperative use of fluorescence imaging for the localization of superficial hepatic tumours. Timing and correct administration of ICG is important.

Fluorescence imaging in colorectal surgery

BACKGROUND

Fluorescent imaging is an emerging technological tool that can guide surgeons during surgery by highlighting anatomical structures and pathology, and help with intraoperative decision making.

METHODS

A comprehensive review of published literature was performed using the search terms "fluorescence", "imaging" and "colorectal surgery" in PubMed. Only clinical trials that were published in English were included in this review. Ex vivo and animal studies were excluded.

RESULTS

This review demonstrates the use of fluorescence imaging in colorectal surgery in four areas: (1) assessment of tissue perfusion and vasculature; (2) assessment of tumour; (3) lymphatic drainage and (4) identification of the urinary tract. The most commonly used fluorescent dyes are nonspecific, such as indocyanine green and methylene blue, but there is increasing interest in the development of specific fluorescently labelled molecular markers.

CONCLUSION

Fluorescence imaging is a potentially useful tool for colorectal surgery. Early studies on fluorescence imaging have been promising but larger scale randomised controlled trials are warranted to demonstrate the effectiveness and benefits of using fluorescence imaging routinely. The development of molecular dyes that are specific to targets could significantly increase the potential use of fluorescence imaging during surgery.

Prospective Non-Randomized Study of Intraoperative Assessment of Surgical Resection Margin of Colo-Rectal Liver Metastases

Introduction: More than 50% of patients with colorectal cancer (CRC) develop liver metastases during the natural course of disease. Surgical resection is currently the most potentially curative method in the treatment of colorectal liver metastases (CRLM). The goal of surgery is to achieve a negative resection margin (RM) of at least 1 mm, which provides the best prognosis for patients. The RM can be assessed by the pathologist of the resected liver specimen (RLS) and by the surgeon intraoperatively. The aim of this research paper is to determine the degree of agreement on intraoperative assessment of the RM by the surgeon and histopathological RM assessment by the pathologist.

Material and methods: This prospective non-randomized double-blind study was approved by the Ethics Committee of the Oncology Institute of Vojvodina and registered on ClinicalTrials.gov #NCT04634526. The study was conducted at the Oncology Institute of Vojvodina, Sremska Kamenica, Serbia. An experienced hepatobiliary surgeon assessed RM for every specimen intra-operatively, immediately after CRLM resection. Resected CRLM lesions were analyzed by two experienced pathologists. These data were compared with pathological RM assessment as a “gold standard”. RM of 1 mm or more was rated as negative RM (RM-). Disease-free survival (DFS) and recurrence rate was calculated by RM status defined by surgeon and by pathologist.

Results: From 01 January 2015 to 31 August 2019, 98 patients were enrolled in the study. There were 219 RLS with 245 CRLM. The surgeon registered positive RM (RM+) of <1mm in 41 (18.7%) RLS. Taking the result of the histopathological assessment (HPA) as the “gold standard”, it was determined that RM was true positive in 32 (14.6%) cases. False positive RM was found in 9 (4.1%) cases. False negative RM was found in 20 (9.1%) cases. True negative RM was found in 158 (72.2%) cases. Sensitivity of surgical assessment (SA) of RM+ was 61.5% (32/52). Specificity of SA of RM+ was 94.6% (158/167). The positive predictive value (PPV) was 78.0% (32/41), while the negative predictive value (NPV) was 88.8% (158/178). The overall accuracy of the RM+ SA was 86.8% (190/219). There was no statistically significant difference in the assessment of RM+ per RLS by surgeon and pathologists (p=0.061), but it was significant when analyses per patients was performed (p=0.017). Recurrence rate for RM+ patients was 48.1% (13/27, p=0.05) for SA and 35.0% (14/40, p=0.17) for HPA. Three year DFS for RM- and RM+ was 66.5% and 27.9% (p=0.04), respectively, by SA, and 64.8% and 42.1% (p=0.106), respectively, by HPA.

Conclusion: Intraoperative assessment of RM- by surgeon of RLS is clinically meaningful. There is not a statistically significant difference in the assessment of RM+ by surgeon and pathologists per RLS, but it was statically significant on a per patient basis. RM determined by surgeon has better prognostic impact on recurrence rate and 1- and 3-year DFS than standard histopathological assessment.

Endoglin/CD105-Based Imaging of Cancer and Cardiovascular Diseases: A Systematic Review

Molecular imaging of pathologic lesions can improve efficient detection of cancer and cardiovascular diseases. A shared pathophysiological feature is angiogenesis, the formation of new blood vessels. Endoglin (CD105) is a coreceptor for ligands of the Transforming Growth Factor-β (TGF-β) family and is highly expressed on angiogenic endothelial cells. Therefore, endoglin-based imaging has been explored to visualize lesions of the aforementioned diseases. This systematic review highlights the progress in endoglin-based imaging of cancer, atherosclerosis, myocardial infarction, and aortic aneurysm, focusing on positron emission tomography (PET), single-photon emission computed tomography (SPECT), magnetic resonance imaging (MRI), near-infrared fluorescence (NIRF) imaging, and ultrasound imaging. PubMed was searched combining the following subjects and their respective synonyms or relevant subterms: "Endoglin", "Imaging/Image-guided surgery". In total, 59 papers were found eligible to be included: 58 reporting about preclinical animal or in vitro models and one ex vivo study in human organs. In addition to exact data extraction of imaging modality type, tumor or cardiovascular disease model, and tracer (class), outcomes were described via a narrative synthesis. Collectively, the data identify endoglin as a suitable target for intraoperative and diagnostic imaging of the neovasculature in tumors, whereas for cardiovascular diseases, the evidence remains scarce but promising.

Sentinel node mapping using indocyanine green and near-infrared fluorescence imaging technology for endometrial cancer: A prospective study using a surgical algorithm in Indian patients

Background:

Indocyanine green (ICG) fluorescence with high-definition, three-dimensional imaging systems is emerging as the latest strategy to reduce trauma and improve surgical outcomes during oncosurgery.

Materials and Methods:

This is a prospective study involving 100 patients with carcinoma endometrium who underwent robotic-assisted Type 1 pan-hysterectomy, with ICG-directed sentinel lymph node (SLN) biopsy from November 2017 to December 2019. The aim was to assess the feasibility and diagnostic accuracy of SLN algorithm and to evaluate the location and distribution of SLN in pelvic, para-aortic and unusual areas and the role of frozen section.

Results:

The overall SLN detection rate was 98%. Bilateral detection was possible in 92% of the cases. Right side was detected in 98% of the cases and left side was visualised in 92% of the cases. Complete node dissection was done where SLN mapping failed. The most common location for SLN in our series was obturator on the right hemipelvis and internal iliac on the left hemipelvis. SLN in the para-aortic area was detected in 14% of cases. In six cases, SLN was found in atypical locations, that is pre-sacral area. Eight patients had SLN positivity for metastasis and underwent complete retroperitoneal lymphadenectomy. Comparison of final histopathological report with frozen section reports showed no false negatives.

Conclusions:

SLN mapping holds a great promise as a modern staging strategy for endometrial cancer. In our experience, cervical injection was an optimal method of mapping the pelvis. ICG showed a high overall detection rate, and bilateral mapping appears to be a feasible alternative to the more traditional methods of SLN mapping in patients with endometrial cancer. The ICG fluorescence imaging system is simple and safe and may become a standard in oncosurgery in view of its staging and anatomical imaging capabilities. This approach can reduce the morbidity, operative times and costs associated with complete lymphadenectomy while maintaining prognostic and predictive information.

Usability of Indocyanine Green in Robot-Assisted Hepatic Surgery

Recent developments in robotic surgery have led to an increasing number of robot-assisted hepatobiliary procedures. However, a limitation of robotic surgery is the missing haptic feedback. The fluorescent dye indocyanine green (ICG) may help in this context, which accumulates in hepatocellular cancers and around hepatic metastasis. ICG accumulation may be visualized by a near-infrared camera integrated into some robotic systems, helping to perform surgery more accurately. We aimed to test the feasibility of preoperative ICG application and its intraoperative use in patients suffering from hepatocellular carcinoma and metastasis of colorectal cancer, but also of other origins. In a single-arm, single-center feasibility study, we tested preoperative ICG application and its intraoperative use in patients undergoing robot-assisted hepatic resections. Twenty patients were included in the final analysis. ICG staining helped in most cases by detecting a clear lesion or additional metastases or when performing an R0 resection. However, it has limitations if applied too late before surgery and in patients suffering from severe liver cirrhosis. ICG staining may serve as a beneficial intraoperative aid in patients undergoing robot-assisted hepatic surgery. Dose and time of application and standardized fluorescence intensity need to be further determined.

Near-infrared fluorescence-guided metastasectomy for hepatic gastrointestinal stromal tumor metastases using indocyanine green: A case report

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Near-infrared fluorescence imaging should be considered as an additional imaging technique to intraoperative ultrasound during surgery for hepatic metastasis.

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Near-infrared fluorescence imaging can aid surgeons in the identification of preoperatively identified liver metastases from primary GIST.

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For the detection of additional superficially located liver metastases from primary GIST near-infrared fluorescence imaging can be used.

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Real-time evaluation of resection margins with NIRF imaging may lead to a lower number of R1 resections.

Introduction and importance

Gastrointestinal stromal tumors are the most prevalent mesenchymal tumors of the gastrointestinal tract. Distant metastases are most often found in the liver or peritoneum with surgery being the preferred treatment option. In our center, fluorescence-guided surgery with indocyanine green is used as standard-of-care for hepatic metastases in colorectal cancer. This case report describes fluorescence-guided metastasectomy for a hepatic gastrointestinal stromal tumor in two patients undergoing open liver resection and radiofrequency ablation.

Case presentation

A 69-year old women was seen during follow-up after laparoscopic resection of a GIST in the lesser curvature of the stomach. Contrast-enhanced computed tomography imaging showed two suspicious lesions in liver segment VI and VIII. Intraoperative near-infrared fluorescence imaging of the liver clearly revealed the lesion in segment VIII, and an additional lesion in segment V – which was not seen on preoperative CT-imaging, neither on intraoperative ultrasonography. The lesion in segment VI was not seen with NIRF imaging due to its deeper location in the liver parenchyma. The second case is an 82-year old man who was also diagnosed with liver metastases from a GIST in the stomach and was scheduled for near-infrared fluorescence-guided liver resection and radio frequency ablation.

Clinical discussion

In this case report we demonstrated the feasibility of fluorescence-guided surgery in detection of liver metastases and treatment planning of two patients with hepatic GIST metastases using indocyanine green.

Conclusion

NIRF-imaging with ICG is useful for identification of preoperatively discovered lesions, surgical resection planning and margin evaluation, and for detection of additional hepatic GIST metastases.

Intraoperative detection of colorectal and pancreatic liver metastases using SGM-101, a fluorescent antibody targeting CEA

BACKGROUND

Fluorescence-guided surgery can provide surgeons with an imaging tool for real-time intraoperative tumor detection. SGM-101, an anti-CEA antibody labelled with a fluorescent dye, is a tumor-specific imaging agent that can aid in improving detection and complete resection for CEA-positive tumors. In this study, the performance of SGM-101 for the detection of colorectal and pancreatic liver metastases was investigated.

METHODS

In this open-label, non-randomized, single-arm pilot study, patients were included with liver metastases from colorectal origin and intraoperatively detected liver metastases from pancreatic origin (during planned pancreatic surgery). SGM-101 was administered two to four days before the scheduled surgery as a single intravenous injection. Intraoperative fluorescence imaging was performed using the Quest Spectrum® imaging system. The performance of SGM-101 was assessed by measuring the intraoperative fluorescence signal and comparing this to histopathology.

RESULTS

A total of 19 lesions were found in 11 patients, which were all suspected as malignant in white light and subsequent fluorescence inspection. Seventeen lesions were malignant with a mean tumor-to-background ratio of 1.7. The remaining two lesions were false-positives as proven by histology.

CONCLUSION

CEA-targeted fluorescence-guided intraoperative tumor detection with SGM-101 is feasible for the detection of colorectal and pancreatic liver metastases.

Real-time surgical margin assessment using ICG-fluorescence during laparoscopic and robot-assisted resections of colorectal liver metastases

Background

Almost a third of the resections in patients with colorectal liver metastases (CRLM) undergoing curative surgery, end up being tumor-margin positive (≤1 mm margin). Near-infrared fluorescent (NIRF) imaging using the fluorescent contrast agent indocyanine green (ICG) has been studied for many different applications. When administered in a relatively low dose (10 mg) 24 hours prior to surgery, ICG accumulated in hepatocytes surrounding the CRLM. This results in the formation of a characteristic fluorescent 'rim' surrounding CRLM when located at the periphery of the liver. By resecting the metastasis with the entire surrounding fluorescent rim, in real-time guided by NIRF imaging, the surgeon can effectively acquire margin-negative (>1 mm) resections. This pilot study aims to describe the surgical technique for using near-infrared fluorescence imaging to assess tumor-margins in vivo in patients with CRLM undergoing laparoscopic or robot-assisted resections.

Methods

Out of our institutional database we selected 16 CRLM based on margin-status (R0; n=8, R1; n=8), which were resected by a minimally-invasive approach using ICG-fluorescence. NIRF images acquired during surgery, from both the resection specimen and the wound bed, were analysed for fluorescent signal. We hypothesized that a protruding fluorescent rim at the parenchymal side of the resection specimen could indicate a too close proximity to the tumor and could be predictive for a tumor-positive surgical margin. NIRF images were correlated to final histopathological assessment of the resection margin.

Results

All lesions with a NIRF positive resection plane in vivo were reported as having a tumor-positive margin. Lesions that showcased no protruding rim in the wound bed in vivo were diagnosed as having a tumor-negative margin in 88% of cases. A 5-step surgical workflow is described to document the NIRF signal was used assess the resection margin in vivo for future clinical studies.

Conclusions

The pilot study shows that image-guided surgery using real-time ICG-fluorescence has the potential to aid surgeons in achieving a tumor-negative margin in minimally invasive liver metastasectomies. The national multi-centre MIMIC-Trial will prospectively study the effect of this technique on surgical tumor-margins (Dutch Trial Register number NL7674).

Fluorescence-guided hepatobiliary surgery with long and short wavelength fluorophores

Importance

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

Objective

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

Evidence Review

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

Findings

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

Conclusions and Relevance for Reviews

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

[Indocyanine green fluorescence staining in liver surgery]

BACKGROUND

Indocyanine green (ICG) opens up numerous possibilities for applications in hepatobiliary surgery, due to its exclusive hepatic excretion and its fluorescence properties in the near infrared (NIR) spectrum.

OBJECTIVE

Systematic review of the literature on the application of ICG imaging in open and laparoscopic liver surgery.

MATERIAL AND METHODS

Literature review and summary of the recent scientific original articles and reviews.

RESULTS

The ICG fluorescence imaging is increasingly being used in liver surgery. It allows real-time display of the segmental anatomy of the liver. Moreover, depending on the tumor entity, direct or indirect visualization of liver tumors and metastases is also possible. The detection of bile leaks might also be facilitated. Recent experiences in liver surgery have shown that ICG imaging enables a more sensitive intraoperative detection of additional foci and probably also a higher R0 resection rate; however, the application is mainly helpful for superficial lesions, since the depth of penetration of NIR is only 8-10 mm.

CONCLUSION

Fluorescence staining using ICG is a valuable supplementary tool in modern liver surgery. It is particularly helpful in laparoscopic surgery where tactile control is eliminated and three-dimensional orientation is difficult. These disadvantages can be partially compensated by additional real-time imaging using ICG.

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

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