Fluorescence navigation with indocyanine green for detecting sentinel lymph nodes in breast cancer

Utility of Indocyanine Green for Sentinel Lymph Node Biopsy in Pediatric Sarcoma and Melanoma

BACKGROUND

Indocyanine green (ICG) is a fluorescent dye with increasing use for adult sentinel lymph node biopsy (SLNB). The utility of ICG in pediatric oncology remains understudied. We aim to describe our experience using ICG for SLNB in pediatrics versus standard blue dye.

METHODS

A retrospective review of pediatric patients with melanoma or sarcoma who underwent SLNB with technetium plus ICG or blue dye from 2014 to 2023 at a large academic children's hospital was conducted.

RESULTS

Twenty-four patients were included; 58.3% were male with median age 13 years (range 4-21 years). The majority had a melanocytic tumor (91.7%) and 8.3% had sarcoma. All patients received technetium with concomitant blue dye (62.5%) or ICG (37.5%). ICG more reliably identified radioactive SLNs, compared to blue dye (mean 100% vs 78.3 ± 8.3%, p = 0.03). There was no significant difference in median operative time (ICG 82 min [68-203] vs blue dye 93 min [78-105], p = 0.84). Seven patients had positive SLNs (29.2%), with recurrence in 2 patients (8.3%) and 1 death (4.2%). There were no adverse events.

CONCLUSION

ICG-directed SLNB in children is a safe and effective alternative to blue dye. Use of ICG did not add to operative time, and more often identified sentinel nodes versus blue dye.

TYPE OF STUDY

Original Research Article, Retrospective Comparative Study.

LEVEL OF EVIDENCE

III.

Intraoperative near-infrared fluorescence guided surgery using indocyanine green (ICG) may aid the surgical removal of benign bone and soft tissue tumours

BACKGROUND

Benign bone and soft tissue tumours encompass a broad, heterogenous range of tumours with varying clinical characteristics. These are often managed surgically with either curettage or marginal excision, but unfortunately have high rates of local recurrence. Indocyanine green (ICG) is a fluorescent dye which can be used to identify solid malignancies intraoperatively but its use is not yet established in benign bone and soft tissue tumours. This study aims to assess whether these tumours fluoresce when administered with ICG pre-operatively and whether this helps surgeons to identify tumour intra-operatively.

PATIENTS AND METHODS

Patients with locally aggressive benign bone and soft tissue tumours were administered with 25-75 mg of ICG preoperatively at the induction of anaesthesia. Fluorescence was imaged intraoperatively using the Stryker SPY-PHI camera.

RESULTS

Of the 12 patients included, 11 tumours fluoresced. The surgeons felt the fluorescence guided the procedure in 7 out of the 11 cases which fluoresced. It was felt to be particularly useful in the curettage of bone tumours, in which curettage could be repeated until the absence of fluorescence on imaging. After 12 months, no patients had local recurrence of the tumour. There were no adverse events recorded in this study and surgeons found the technology acceptable.

CONCLUSIONS

The use of ICG for fluorescence guided surgery is a promising technology to improve outcomes of surgery for benign bone and soft tissue tumours. Further, longer term, study with a control arm is needed to identify whether it results in a reduction in the local recurrence rate.

The realization of medical devices for precision surgery - development and implementation of 'stop-and-go' imaging technologies

INTRODUCTION

Surgery and biomedical imaging encompass a big share of the medical-device market. The ever-mounting demand for precision surgery has driven the integration of these two into the field of image-guided surgery. A key-question herein is how imaging modalities can guide the surgical decision-making process. Through performance-based design, chemists, engineers, and doctors need to build a bridge between imaging technologies and surgical challenges.

AREAS-COVERED

This perspective article highlights the complementary nature between the technological design of an image-guidance modality and the type of procedure performed. The specific roles of the involved professionals, imaging technologies, and surgical indications are addressed.

EXPERT-OPINION

Molecular-image-guided surgery has the potential to advance pre-, intra- and post-operative tissue characterization. To achieve this, surgeons need the access to well-designed indication-specific chemical-agents and detection modalities. Hereby, some technologies stimulate exploration ('go'), while others stimulate caution ('stop'). However, failing to adequately address the indication-specific needs rises the risk of incorrect tool employment and sub-optimal surgical performance. Therefore, besides the availability of new technologies, market growth is highly dependent on the practical nature and impact on real-life clinical care. While urology currently takes the lead in the widespread implementation of image-guidance technologies, the topic is generic and its popularity spreads rapidly within surgical oncology.

A Multiresolution Approach with Method-Informed Statistical Analysis for Quantifying Lymphatic Pumping Dynamics

Despite significant strides in lymphatic system imaging, the timely diagnosis of lymphatic disorders remains elusive. One main cause for this is the absence of standardized, quantitative methods for real-time analysis of lymphatic contractility. Here, we address this unmet need by combining near-infrared lymphangiography imaging with an innovative analytical workflow. We combined data acquisition, signal processing, and statistical analysis to integrate traditional peak and-valley with advanced wavelet time-frequency analyses. Decision theory was used to evaluate the primary drivers of attributable variance in lymphangiography measurements to generate a strategy for optimizing the number of repeat measurements needed per subject to increase measurement reliability. This approach not only offers detailed insights into lymphatic pumping behaviors across species, sex and age, but also significantly boosts the reliability of these measurements by incorporating multiple regions of interest and evaluating the lymphatic system under various gravitational loads. By addressing the critical need for improved imaging and quantification methods, our study offers a new standard approach for the imaging and analysis of lymphatic function that can improve our understanding, diagnosis, and treatment of lymphatic diseases. The results highlight the importance of comprehensive data acquisition strategies to fully capture the dynamic behavior of the lymphatic system.

Indocyanine green fluorescence versus blue dye, technetium-99M, and the dual-marker combination of technetium-99M + blue dye for sentinel lymph node detection in early breast cancer-meta-analysis including consistency analysis

BACKGROUND

Axillary sentinel lymph node biopsies are standard of care in patients with breast cancer and no clinically apparent metastases. Traditionally, technetium-99m, blue dye, or both have been used to identify sentinel lymph nodes. However, blue dyes miss up to 40% of sentinel lymph nodes, while technetium-99m use is complex, costly, and exposes patients to radiation. Over the past decade, studies have consistently found the biologically inert fluorescent indocyanine green to be 95% to 100% sensitive in detecting breast cancer sentinel lymph nodes, yet indocyanine green remains infrequently used.

METHODS

We conducted an extensive meta-analysis comparing indocyanine green against blue dye, technetium-99m, and the dual-marker combination of technetium-99m + BD. Unlike prior meta-analyses that only assessed either per-case or per-node sentinel lymph node detection, we analyzed the following 5 metrics: per-case and per-node sentinel lymph node detection and metastasis-positive sentinel lymph node sensitivity, and mean number of sentinel lymph nodes/case. We further examined the consistency and magnitude of between-study superiority and statistically significant within-study superiority of each marker against others.

RESULTS

For every metric and analysis approach, indocyanine green was clearly superior to blue dye and at least non-inferior, if not superior, to technetium-99m and technetium-99m + blue dye. Assessing the consistency of superiority by at least 2.0%, indocyanine green was superior to blue dye 73 times versus 1, to technetium-99m 42 times versus 9, and to technetium-99m + blue dye 6 times versus 0. Within-study statistically significant differences favored indocyanine green over blue dye 29 times versus 0 and over technetium-99m 11 times versus 2.

DISCUSSION

For sentinel lymph node detection in patients with breast cancer with no clinically apparent metastases, indocyanine green is clearly and consistently superior to blue dye and either non-inferior or superior to technetium-99m and technetium-99m + blue dye.

Revolutionizing lymph node metastasis imaging: the role of drug delivery systems and future perspectives

The deployment of imaging examinations has evolved into a robust approach for the diagnosis of lymph node metastasis (LNM). The advancement of technology, coupled with the introduction of innovative imaging drugs, has led to the incorporation of an increasingly diverse array of imaging techniques into clinical practice. Nonetheless, conventional methods of administering imaging agents persist in presenting certain drawbacks and side effects. The employment of controlled drug delivery systems (DDSs) as a conduit for transporting imaging agents offers a promising solution to ameliorate these limitations intrinsic to metastatic lymph node (LN) imaging, thereby augmenting diagnostic precision. Within the scope of this review, we elucidate the historical context of LN imaging and encapsulate the frequently employed DDSs in conjunction with a variety of imaging techniques, specifically for metastatic LN imaging. Moreover, we engage in a discourse on the conceptualization and practical application of fusing diagnosis and treatment by employing DDSs. Finally, we venture into prospective applications of DDSs in the realm of LNM imaging and share our perspective on the potential trajectory of DDS development.

Indocyanine green: The guide to safer and more effective surgery

In this editorial we comment on the article by Kalayarasan and co-workers published in the recent issue of the World Journal of Gastrointestinal Surgery. The authors present an interesting review on the use of indocyanine green fluorescence in different aspects of abdominal surgery. They also highlight future perspectives of the use of indocyanine green in mini-invasive surgery. Indocyanine green, used for fluorescence imaging, has been approved by the Food and Drug Administration and is safe for use in humans. It can be administered intravenously or intra-arterially. Since its advent, there have been several advancements in the applications of indocyanine green, especially in the surgical field, such as intraoperative mapping and biopsy of sentinel lymph node, measurement of hepatic function prior to resection, in neurosurgical cases to detect vascular anomalies, in cardiovascular cases for patency and assessment of vascular abnormalities, in predicting healing following amputations, in helping visualization of hepatobiliary anatomy and blood vessels, in reconstructive surgery, to assess flap viability and for the evaluation of tissue perfusion following major trauma and burns. For these reasons, the intraoperative use of indocyanine green has become common in a variety of surgical specialties and transplant surgery. Colorectal surgery has just lately begun to adopt this technique, particularly for perfusion visualization to prevent anastomotic leakage. The regular use of indocyanine green coupled with fluorescence angiography has recently been proposed as a feasible tool to help improve patient outcomes. Using the best available data, it has been shown that routine use of indocyanine green in colorectal surgery reduces the rates of anastomotic leak. The use of indocyanine green is proven to be safe, feasible, and effective in both elective and emergency scenarios. However, additional robust evidence from larger-scale, high-quality studies is essential before incorporating indocyanine green guided surgery into standard practice.

Current surgical management for melanoma

Melanoma is a major malignant cutaneous neoplasm with a high mortality rate. In recent years, the treatment of melanoma has developed dramatically with the invention of new therapeutic agents, including immune checkpoint inhibitors and molecular-targeted agents. These agents are available as adjuvant therapies for postoperative patients with stage IIB, IIC, and III melanomas. Furthermore, neoadjuvant therapy has been studied in several global clinical trials and has demonstrated promising and favorable clinical efficacy, mainly in patients with palpable regional lymph nodes. A recent large phase III clinical trial investigating early lymph node dissection for sentinel lymph node metastases demonstrated no survival benefits. Based on these data, surgery should be reconsidered as an appropriate treatment modality for melanoma. The need for invasive surgical procedures will be reduced with the invention of effective adjuvant and neoadjuvant therapies and novel clinical trial data on regional lymph node dissection. However, surgery still plays an important role in treating early-stage melanoma, accurately determining the disease stage, and effective palliative treatment for advanced melanoma. In this article, we focus on surgery for primary tumors, regional lymph nodes, and metastatic sites in an era of remarkably revolutionary drug treatments for melanoma.

A new lymphography protocol and interpretation principles based on functional lymphatic anatomy in lower limb lymphedema

Indirect lymphatic system imaging is essential for diagnosing lymphatic diseases. The basic methodology involves intradermal or subcutaneous injection of a contrast agent into the surrounding lymphatic capillary, and the flow of the contrast agent is identified using a detector. Many contrast agents that use near-infrared dye, including indocyanine green (ICG) fluorescent lymphography, are available. ICG is rapidly spreading as a convenient and safe lymphedema diagnostic method, because it does not involve radiation exposure, and the imaging equipment is more compact than other devices. The lymphatic system is a semi-open circulatory system with numerous lymphatic capillaries acting as blind ends. Anatomical information on the injection site and observation of specific lymphatic vessels and nodes is important. However, this anatomical information is lacking. Recent reports suggest that ICG fluorescent lymphography can be applied to cadavers in the same manner as living bodies. Furthermore, these reports have demonstrated the functional aspects of the capillary lymph vessel networks as well as their relationship with lymphatic vessels and lymph nodes. This review article describes the historical progression from the old to the new functional lymphatic anatomy and introduces a new functional lymphography technique for the lower limbs.

Don't forget emergency surgery! Lessons to learn from elective indocyanine green-guided gastrointestinal interventions

Fluorescence-based imaging has found application in several fields of elective surgery, but there is still a lack of evidence in the literature about its use in the emergency setting. Clinical trials have consistently shown that indocyanine green (ICG)-guided surgery can dramatically reduce the risk of postoperative complications, length of in-hospital stay and total healthcare costs in the elective setting. It is well-known that emergency surgery has a higher complication rate than its elective counterpart, therefore an impelling need for research studies to explore, validate and develop this issue has been highlighted. The present editorial aims to provide a critical overview of currently available applications and pitfalls of ICG fluorescence in abdominal emergencies. Furthermore, we evidenced how the experience of ICG-fluorescence in elective surgery might be of great help in implementing its use in acute situations. In the first paragraph we analyzed the tips and tricks of ICG-guided cancer surgery that might be exploited in acute cases. We then deepened the two most described topics in ICG-guided emergency surgery: Acute cholecystitis and intestinal ischemia, focusing on both the advantages and limitations of green-fluorescence application in these two fields. In emergency situations, ICG fluorescence demonstrates a promising role in preventing undue intestinal resections or their entity, facilitating the detection of intestinal ischemic zones, identifying biliary tree anatomy, reducing post-operative complications, and mitigating high mortality rates. The need to improve its application still exists, therefore we strongly believe that the elective and routinary use of the dye is the best way to acquire the necessary skills for emergency procedures.

Clinical use of Indocyanine green fluorescence method for sentinel lymph node biopsy in breast cancer in France in 2021

INTRODUCTION

Indocyanine green (ICG) for axillary sentinel lymph node (SLN) detection in early breast cancer is at least equivalent to radioisotopic and/or colorimetric techniques. This procedure has not yet been recommended by learned societies in France. Following the recent drug approval of Infracyanin ® in this indication, we wished to study the use of ICG in France.

METHODS

We conducted a web-based survey among members of multiple French breast cancer societies throughout November 2021. The survey assessed the profile of the respondent, the use or not of ICG for the detection of SLN in breast cancer, the technique used and the opinion of non-users and their expectations on the subject.

RESULTS

Seventy-five surgeons participated. More than a third (37 %) have been using ICG for the detection of SLN in breast cancer for 2 to 3 years. Technique was highly variable. According to 82.1 % of the respondents, less than 20 procedures are necessary to master the use of ICG. The main advantage reported for this method is the reduction of organizational constraints. The obstacles to the use of the ICG are the near infra-red camera equipment, but also the lack of validation by the French guidelines. Among non-users, 83 % would like to develop this technique in their center and 72.3 % are interested in training on this subject.

CONCLUSION

This work highlights the need for French learned societies to take a stand on this issue but also the need to carry out studies on the technical aspects in order to standardise practices.

[Fluorescence lymphography for sentinal lymph node biopsy in breast cancer]

OBJECTIVE

To study diagnostic value of fluorescence lymphography for sentinel lymph node biopsy in breast cancer.

MATERIAL AND METHODS

The study enrolled 25 patients with breast cancer T1-2N0-1M0 between March 2023 and July 2023. Eight ones underwent neoadjuvant chemotherapy. In 3 patients, morphologically verified metastases cN1 in axillary lymph nodes regressed after treatment. After sentinel lymph node biopsy, all patients underwent standard axillary lymphadenectomy. Subareolar injection of indocyanine green 1 ml (5 mg/ml) was performed immediately before surgery. Fluorescence imaging was performed using the MARS system.

RESULTS

Detection rate was 100%. Mean number of sentinel lymph nodes was 2. Metastatic lesions of sentinel lymph nodes were observed in 6 patients (24%) with micro-metastases in 2 cases. In 50% of cases, metastatic lesion did not extend beyond sentinel lymph nodes. False negative result was obtained in 1 (4%) patient. Mean number of metastases was 1.8 (max 3 in one patient).

CONCLUSION

Sentinel lymph node biopsy with fluorescence lymphography is a sensitive method. The advantages of this technique are visualization of subcutaneous lymphatic vessels and skin incision for access to sentinel lymph nodes, as well as visualization of sentinel lymph nodes after skin incision.

Indocyanine green fluorescence in gastrointestinal surgery: Appraisal of current evidence

Applying indocyanine green (ICG) fluorescence in surgery has created a new dimension of navigation surgery to advance in various disciplines. The research in this field is nascent and fragmented, necessitating academic efforts to gain a comprehensive understanding. The present review aims to integrate diverse perspectives and recent advances in its application in gastrointestinal surgery. The relevant articles were selected by using the appropriate keyword search in PubMed. The angiography and cholangiography property of ICG fluorescence is helpful in various hepatobiliary disorders. In gastroesophageal and colorectal surgery, the lymphangiography and angiography property of ICG is applied to evaluate bowel vascularity and guide lymphadenectomy. The lack of objective parameters to assess ICG fluorescence has been the primary limitation when ICG is used to evaluate bowel perfusion. The optimum dose and timing of ICG administration need to be standardized in some new application areas in gastrointestinal surgery. Binding tumor-specific ligands with fluorophores can potentially widen the fluorescence application to detect primary and metastatic gastrointestinal tumors. The narrative review outlines prior contributions, limitations, and research opportunities for future studies across gastrointestinal sub-specialty. The findings of the present review would be helpful for scholars and practitioners to explore and progress in this exciting domain of gastrointestinal surgery.

An Updated Review on the Emerging Role of Indocyanine Green (ICG) as a Sentinel Lymph Node Tracer in Breast Cancer

Sentinel lymph node biopsy (SLNB) has become the standard of care for clinically node-negative breast cancer and has recently been shown by clinical trials to be also feasible for clinically node-positive patients treated with primary systemic therapy. The dual technique using both radioisotope (RI) and blue dye (BD) as tracers for the identification of sentinel lymph nodes is considered the gold standard. However, allergic reactions to blue dye as well as logistics issues related to the use of radioactive agents, have led to research on new sentinel lymph node (SLN) tracers and to the development and introduction of novel techniques in the clinical practice. Indocyanine green (ICG) is a water-soluble dye with fluorescent properties in the near-infrared (NIR) spectrum. ICG has been shown to be safe and effective as a tracer during SLNB for breast cancer and accumulating evidence suggests that ICG is superior to BD and at least comparable to RI alone and to RI combined with BD. Thus, ICG was recently proposed as a reliable SLN tracer in some breast cancer clinical practice guidelines. Nevertheless, there is lack of consensus regarding the optimal role of ICG for SLN mapping. Specifically, it is yet to be determined whether ICG should be used in addition to BD and/or RI, or if ICG could potentially replace these long-established traditional SLN tracers. This article is an updated overview of somerecent studies that compared ICG with BD and/or RI regarding their accuracy and effectiveness during SLNB for breast cancer.

A Novel Injection Protocol Using Voluven®-Assisted Indocyanine Green with Improved Near-Infrared Fluorescence Guidance in Breast Cancer Sentinel Lymph Node Mapping-A Translational Study

BACKGROUND

Near-infrared (NIR) fluorescence-guided surgery with indocyanine green (ICG) has been demonstrated to provide high sensitivity in sentinel lymph node biopsy (SLNB) for breast cancer but has several limitations, such as unstable pharmacokinetics, limited fluorescence brightness, and undesired diffusion to neighboring tissues. This paper investigates the use of Voluven® as the solvent for ICG fluorescence-guided SLNB (ICG-SLNB).

METHODS

The photophysical properties of ICG in water and Voluven® were evaluated in laboratory experiments and in a mouse model. Nine patients with early breast cancer underwent subareolar injection of diluted ICG (0.25 mg/ml) for ICG-SLNB. Six of the nine patients received ICG dissolved in Voluven® (ICG:Voluven®), while three were administered ICG dissolved in water (ICG:water); a repetitive injection-observation protocol was followed for all patients. The mapping image quality was evaluated.

RESULTS

Laboratory experiments and in vivo mouse study showed improved fluorescence and better targeting using Voluven® as the solvent. ICG-SLNB with a repetitive injection-observation protocol was successfully performed in all nine patients. ICG:Voluven® administration had an overall better signal-to-background ratio (SBR) in sequential sentinel lymph nodes. The rates of transportation within the lymphatics were also improved using ICG:Voluven® compared with ICG:water.

CONCLUSIONS

From basic research to animal models to in-human trial, our study proposes a repetitive injection-observation technique with ICG:Voluven®, which is characterized by better transportation and more stable mapping quality for ICG-SLNB in breast cancer patients.

How to objectively evaluate the impact of image-guided surgery technologies

PURPOSE

This manuscript aims to provide a better understanding of methods and techniques with which one can better quantify the impact of image-guided surgical technologies.

METHODS

A literature review was conducted with regard to economic and technical methods of medical device evaluation in various countries. Attention was focused on applications related to image-guided interventions that have enabled procedures to be performed in a minimally invasive manner, produced superior clinical outcomes, or have become standard of care.

RESULTS

The review provides examples of successful implementations and adoption of image-guided surgical techniques, mostly in the field of neurosurgery. Failures as well as newly developed technologies still undergoing cost-efficacy analysis are discussed.

CONCLUSION

The field of image-guided surgery has evolved from solely using preoperative images to utilizing highly specific tools and software to provide more information to the interventionalist in real time. While deformations in soft tissue often preclude the use of such instruments outside of neurosurgery, recent developments in optical and radioactive guidance have enabled surgeons to better account for organ motion and provide feedback to the surgeon as tissue is cut. These technologies are currently undergoing value assessments in many countries and hold promise to improve outcomes for patients, surgeons, care teams, payors, and society in general.

Lymphatic flow mapping using near-infrared fluorescence imaging with indocyanine green helps to predict lymph node metastasis intraoperatively in patients with esophageal or esophagogastric junction cancer not treated with neoadjuvant chemotherapy

BACKGROUND

Lymphatic flow mapping using near-infrared fluorescence (NIR) imaging with indocyanine green (ICG) has been used for the intraoperative prediction of lymph node metastasis in esophageal or esophagogastric junction cancer. However, a consistent method that yields sufficient diagnostic quality is yet to be confirmed. This study explored the diagnostic utility of our newly established lymphatic flow mapping protocol for predicting lymph node metastasis in patients with esophageal or esophagogastric junction cancer.

METHODS

We injected 0.5 mL of ICG (500 μg/mL) into the submucosal layer at four peritumoral points on the day before surgery for 54 patients. We performed lymphatic flow mapping intraoperatively using NIR imaging. After determining the NIR status and presence of metastases, evaluable lymph node stations on in vivo imaging and all resected lymph nodes were divided into four categories: ICG+meta+ (true positive), ICG+meta- (false positive), ICG-meta+ (false negative), and ICG-meta- (true negative).

RESULTS

The distribution of ICG+ and meta+ lymph node stations differed according to the primary tumor site. Sensitivity and specificity for predicting meta+ lymph nodes among ICG+ ones were 50% (95% CI 41-59%) and 75% (73-76%), respectively. Predicting meta+ lymph node stations among ICG+ stations improved these values to 66% (54-77%) and 77% (74-79%), respectively. Undergoing neoadjuvant chemotherapy was an independent risk factor for having meta+ lymph nodes with false-negative diagnoses (odds ratio 4.82; 95% CI 1.28-18.19). The sensitivity of our technique for predicting meta+ lymph nodes and meta+ lymph node stations in patients who did not undergo neoadjuvant chemotherapy was 79% (63-90%) and 83% (61-94%), respectively.

CONCLUSION

Our protocol potentially helps to predict lymph node metastasis intraoperatively in patients with esophageal or esophagogastric junction cancer undergoing esophagectomy who did not undergo neoadjuvant chemotherapy.

Comparison of Sentinel Lymph Node Biopsy by Blue Dye Conjunction With Indocyanine Green or Radioisotope in Early-Stage Breast Cancer: A Prospective Single-Center Observational Study

Background

Although radioisotope (RI) combined with blue dye (BD) is the standard technique for sentinel lymph node (SLN) biopsy in breast cancer, the use of RI is limited at some institutions due to the specific equipment needed. Indocyanine green (ICG) fluorescence detection has been developed as a potential substitute for RI method. However, reports on the sensitivity of ICG and RI techniques in detecting SLN are inconsistent; hence, the present study was designed to compare the clinical efficacy between the combined method of ICG + BD (ICG-B) and RI + BD (RI-B).

Methods

A prospective observational study was performed that identified 138 breast cancer patients who had undergone lymphatic mapping and SLN biopsy with ICG-B or RI-B. The SLN detection rate, positive SLN counts, and lymph node metastasis between the 2 groups were compared.

Results

A total of 71 patients were recruited in the ICG-B group, while 67 were recruited in the RI-B group. The SLN detection rate was 100% in both the ICG-B and RI-B groups. Lymph node metastasis was found in 13 patients using ICG-B and in 12 patients using the RI-B technique (18.31% vs 17.91%, respectively; P = .61). No significant differences were observed in the positive SLN counts (3.12 ± 2.01 vs 3.33 ± 2.24, P = .37) between the 2 groups.

Conclusions

Indocyanine green combined with BD has an equal efficacy compared with RI plus BD when performing an axillary SLN biopsy in breast cancer. The ICG plus BD procedure is a promising alternative to traditional standard mapping methods.

Evaluation of the efficacy of using indocyanine green associated with fluorescence in sentinel lymph node biopsy

INTRODUCTION

Sentinel lymph node biopsy is the technique recommended for the axillary staging of patients with breast cancer in the initial stages without clinical axillary involvement. Three techniques are widely used globally to detect sentinel lymph nodes: patent blue, the radiopharmaceutical technetium 99 with gamma probe, and the combination of these two.

OBJECTIVES

To evaluate the sentinel lymph node detection rate with an innovative technique: indocyanine green (ICG) associated with fluorescence in breast cancer patients, and compare it with patent blue and a combination of patent blue and indocyanine green.

METHODS

99 patients were sequentially (not randomly) allocated into 3 arms with 33 patients submitted to sentinel lymph node techniques. One arm underwent patent blue dying, the other indocyanine green, and the third received a combination of both. The detection rates between arms were compared.

RESULTS

The detection rate in identifying the sentinel lymph node was 78.8% with patent blue, 93.9% with indocyanine green, and 100% with the combination. Indocyanine green identified two sentinel nodes in 48.5% of patients; the other groups more commonly had only one node identified. The mean time to sentinel lymph node identification was 20.6 ± 10.7 SD (standard deviation) minutes among patients submitted to the patent blue dye, 8.6 ± 6.6 minutes in the indocyanine green arm, and 10 ± 8.9 minutes in the combined group (P<0.001; Student's test). The mean surgery time was 69.4 ± 16.9; 55.1 ± 13.9; and 69.4 ± 19.3 minutes respectively (P<0.001; Student's test).

CONCLUSIONS

The sentinel lymph node detection rate by fluorescence using indocyanine green was 93.9%, considered adequate. The rates using patent blue, indocyanine green, and patent blue plus indocyanine green (combined) were significantly different, and the indocyanine green alone is also acceptable, since it has a good performance in sentinel lymph node identification and it can avoid tattooing, with a 100% sentinel lymph node detection rate when combined with patent blue.

Advancement of Near Infrared-II Organic Dyes in Bioimaging

In recent decades, small organic compounds having absorption and fluorescence emission in the second near-infrared (NIR-II, 1000-1700 nm) bio-window have attracted a lot of interest. Fluorescence bioimaging may be used by researchers and surgeons to genomically focus an array of biological areas and functions. The near-infrared-II (NIR-II) dye which has fluorescent imaging, bypasses the visible imaging striking barrier, making it a valuable tool for cancer early detection and very sensitive tumor resection. It can generate sub-cellular density scanning data directly and has been applied to biological and medical detection and therapy. This paper discusses the history and current state of theranostics and biosensing uses of NIR-II tiny organic producers depending on multiple skeletons. For biological imaging, organic dyes are extensively used as markers for near-infrared (NIR) fluorescent though the issue lies in instability and hydrophobicity for bio environment which is a major restriction for its utilization. Various conjugation with the probes is also adopted in order to increase the biosensing power and efficiency and to deduct their level of cytotoxicity. Some of these combinations are discussed in the paper including supramolecule usage, combining the probes with quantum dots, and an alloy of gold selenium. NIR-II fluorescence devices are also used in combination with confocal microscopy to study the cytological interaction of proteins. Several research papers stated using cell membrane enhancement units empowered with oxazolepyridine and coumarin compounds. As the need for bioimaging increases decade by decade these cons of using organic dyes alone are getting overlapped by compounding these dyes with materials that help in better penetration, bioavailability, and reduction in areas of toxicity.

Single-port endoscopic-sentinel lymph node biopsy combined with indocyanine green and carbon nanoparticles in breast cancer

BACKGROUND

In order to explore the surgical safety and the reliability of axillary staging of single-port endoscopic-sentinel lymph node biopsy, we combined it with indocyanine green that was excited by near-infrared fluorescence endoscopy and carbon nanoparticles as a tracer and compared this method to conventional open sentinel lymph node biopsy.

METHODS

This is a retrospective and observational study, there were 20 patients in each group and the total sample size was 60: Group 1, single-port endoscopic-sentinel lymph node biopsy combined with indocyanine green and carbon nanoparticles; Group 2, single-port endoscopic-sentinel lymph node biopsy with carbon nanoparticles only; Group 3, conventional sentinel lymph node biopsy with indocyanine green and carbon nanoparticles. Sentinel lymph node detection and upper extremity function were determined to measure the safety and efficacy of the novel single-port endoscopic-sentinel lymph node biopsy (SPE-SLNB) technique to the standard conventional sentinel lymph node biopsy technique.

RESULTS

The detection rate of sentinel lymph nodes was 100% in Group 1, 100% in Group 2, and 95% in Group 3. There were no significant differences in upper arm function and pain scores between the three groups.

CONCLUSION

The novel technique of combining indocyanine green and carbon nanoparticles with single-port endoscopic-sentinel lymph node biopsy achieved a similar detection rate and mean number of sentinel lymph nodes as conventional sentinel lymph node biopsy. Traditional open surgery requires two different incisions for breast surgery and SLNB. While the most important advantage of SPE-SLNB is that two procedures can be effectively performed through a single-port in the axilla Therefore, for patients who meet the indications, single-port endoscopic-sentinel lymph node biopsy is as safe and reliable as conventional sentinel lymph node biopsy but has the aesthetic advantage of only one incision.

Application of fluorescence-guided surgery in the acute care setting: a systematic literature review

PURPOSE

Fluorescence-based imaging has found application in several fields of elective surgery, but there is still a lack of evidence in the literature about its use in emergency setting. The present review critically summarizes currently available applications and limitations of indocyanine green (ICG) fluorescence in abdominal emergencies including acute cholecystitis, mesenteric ischemia, and trauma surgery.

METHODS

A systematic review was performed according to the PRISMA statement identifying articles about the use of ICG fluorescence in the management of the most common general surgery emergency. Only studies focusing on the use of ICG fluorescence for the management of acute surgical conditions in adults were included.

RESULTS

Thirty-six articles were considered for qualitative analysis. The most frequent disease was occlusive or non-occlusive mesenteric ischemia followed by acute cholecystitis. Benefits from using ICG for acute cholecystitis were reported in 48% of cases (clear identification of biliary structures and a safer surgical procedure). In one hundred and twenty cases that concerned the use of ICG for occlusive or non-occlusive mesenteric ischemia, ICG injection led to a modification of the surgical decision in 44 patients (36.6%). Three studies evaluated the use of ICG in trauma patients to assess the viability of bowel or parenchymatous organs in abdominal trauma, to evaluate the perfusion-related tissue impairment in extremity or craniofacial trauma, and to reassess the efficacy of surgical procedures performed in terms of vascularization. ICG injection led to a modification of the surgical decision in 50 patients (23.9%).

CONCLUSION

ICG fluorescence is a safe and feasible tool also in an emergency setting. There is increasing evidence that the use of ICG fluorescence during abdominal surgery could facilitate intra-operative decision-making and improve patient outcomes, even in the field of emergency surgery.

Evaluation of Dual Dye Technique for Sentinel Lymph Node Biopsy in Breast Cancer: Two-Arm Open-Label Parallel Design Non-Inferiority Randomized Controlled Trial

INTRODUCTION

Radioisotope and blue dye are standard agents for performing sentinel lymph node (SLN) biopsy in breast cancer. The paucity of nuclear medicine facility poses logistic challenge. This study evaluated performance of radioisotope & methylene blue (MB) with indocyanine green (ICG) and MB for SLNB.

PATIENTS AND METHODS

This randomized controlled trial was conducted from December 2019 to July 2022 comparing SLN identification proportions of radioisotope-blue dye [Group A] with dual dye (MB + ICG; Group B]. Secondary objective included time required and cost effectiveness of performing SLNB. Sample size of 70 (35 in each arm) was calculated. Upfront operable node negative early breast cancer was included in the study. Clinico-demographic data, number & type of SLN, time taken were noted. Cost analysis was done including the equipment, manpower & consumables. Chi-square/Fisher exact test was used to compare proportion between two groups. p value of less than 0.05 was considered to represent statistical significance.

RESULTS

Seventy patients randomized to either group were similar in clinico-demographic and tumor characteristics. SLN identification rate (IR) was 91.43% in group A and 100% in group B. Overall IR of MB, radioisotope and ICG were 91.43%, 91.43% and 100%, respectively. Mean number of SLNs identified were 3 in group A and 4 in group B. Median time required for SLNB was 12 min and 14 min in either group, respectively. Cost of performing SLNB was higher in Group B.

CONCLUSION

SLNB using dual dye is non-inferior to radioisotope-blue dye in upfront operable early breast cancer. Trial registration number Clinical Trial registry India CTRI/2020/02/023503.

Innovation versus Experimentation: An Application of Ethical Frameworks to the Acceptance of Fluorescence-Guided Pediatric Surgery

Innovation is essential to the advancement of the field of pediatric surgery. The natural skepticism toward new technologies in pediatrics leads to frequent confusion of surgical innovation and research. Using fluorescence-guided surgery as an archetype for this ethical discussion, we apply existing conceptual frameworks of surgical innovation to understand the distinction between innovation and experimentation, acknowledging the spectrum and "grey zone" in between. In this review, we discuss the role of Institutional Review Boards in evaluating surgical practice innovations, and the aspects of certain surgical innovations that are distinct from experimentation, including a thorough understanding of the risk profile, preexisting use in humans, and adaptation from related fields. Examining fluorescence-guided surgery through these existing frameworks as well as the concept of equipoise, we conclude that new applications of indocyanine green do not constitute human subjects research. Most importantly, this example gives practitioners a lens through which they may appraise potential surgical innovations to allow for a sensible and efficient improvement of the field of pediatric surgery. LEVEL OF EVIDENCE: V.

Criteria for Preserving Grossly Ischemic Torsed Testicles Using Indocyanine Green Fluorescence Imaging: A Single-Center Case Series

Testicular torsion (TT) is a surgical emergency requiring early diagnosis and surgical intervention to avoid testicular loss. We report 3 pediatric TT cases with testicular salvage to visualize the blood flow by indocyanine green fluorescence imaging (ICG-FI) on the tunica albuginea of the testis. ICG-FI could not confirm blood flow in the testicular parenchyma; however, it could be detected in postoperative ultrasonography. Blood visualization of the tunica albuginea by ICG-FI may have potential criteria for testicular salvage. Long-term follow-up investigations after testicular salvage are needed to conclude the ICG-FI efficacy for TT.

Release of liposomally formulated near-infrared fluorescent probes included in giant cluster vesicles by ultrasound irradiation

Detection of tumors and regional lymph nodes during surgery has been proposed in the diagnosis of lymphatic metastasis and the surgical treatment of malignant diseases. Giant cluster vesicles (GCVs), including liposomally formulated indocyanine green (LP-ICG) derivatives, are a possible candidate for agents to realize the two contradictory properties, i.e., retention in tissue for lesion-marking and trace for sentinel lymph nodes (SLNs) identification. We attempted to release the LP-ICG derivatives from GCVs using ultrasound contrast agents (UCAs) under ultrasound irradiation. An absorption spectrophotometer quantitatively evaluated the amounts of released LP-ICG derivatives. As a result, we demonstrated that it depended on conditions for sound pressure, burst length, and number density of UCAs, and had a sound pressure threshold independent of burst length and number density of UCAs. The results will aid to determine appropriate conditions to maximize the released amount of LP-ICG derivatives while keeping safety.

Fluorescence-guided surgery: comprehensive review

BACKGROUND

Despite significant improvements in preoperative workup and surgical planning, surgeons often rely on their eyes and hands during surgery. Although this can be sufficient in some patients, intraoperative guidance is highly desirable. Near-infrared fluorescence has been advocated as a potential technique to guide surgeons during surgery.

METHODS

A literature search was conducted to identify relevant articles for fluorescence-guided surgery. The literature search was performed using Medical Subject Headings on PubMed for articles in English until November 2022 and a narrative review undertaken.

RESULTS

The use of invisible light, enabling real-time imaging, superior penetration depth, and the possibility to use targeted imaging agents, makes this optical imaging technique increasingly popular. Four main indications are described in this review: tissue perfusion, lymph node assessment, anatomy of vital structures, and tumour tissue imaging. Furthermore, this review provides an overview of future opportunities in the field of fluorescence-guided surgery.

CONCLUSION

Fluorescence-guided surgery has proven to be a widely innovative technique applicable in many fields of surgery. The potential indications for its use are diverse and can be combined. The big challenge for the future will be in bringing experimental fluorophores and conjugates through trials and into clinical practice, as well as validation of computer visualization with large data sets. This will require collaborative surgical groups focusing on utility, efficacy, and outcomes for these techniques.

Proteomes of Micro- and Nanosized Carriers Engineered from Red Blood Cells

Red blood cell (RBC)-derived systems offer a potential platform for delivery of biomedical cargos. Although the importance of specific proteins associated with the biodistribution and pharmacokinetics of these particles has been recognized, it remains to be explored whether some of the key transmembrane and cytoskeletal proteins responsible for immune-modulatory effects and mechanical integrity of the particles are retained. Herein, using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and quantitative tandem mass tag mass spectrometry in conjunction with bioinformatics analysis, we have examined the proteomes of micro- and nanosized erythrocyte ghosts doped with indocyanine green and compared them with those of RBCs. We identified a total of 884 proteins in each set of RBCs, micro-, and nanosized particles, of which 8 and 45 proteins were expressed at significantly different relative abundances when comparing micro-sized particles vs RBCs and nanosized particles vs RBCs, respectively. We found greater differences in relative abundances of some mechano-modulatory proteins, such as band 3 and protein 4.2, and immunomodulatory proteins like CD44, CD47, and CD55 in nanosized particles as compared to RBCs. Our findings highlight that the methods utilized in fabricating RBC-based systems can induce substantial effects on their proteomes. Mass spectrometry data are available at ProteomeXchange with the identifier PXD038780.

Impact of near-infrared fluorescence imaging with indocyanine green on the surgical treatment of pulmonary masses in dogs

Objectives

To investigate the intraoperative identification and complete resection of pulmonary masses, and to evaluate lymph node metastasis of pulmonary malignant tumors in dogs using indocyanine green (ICG) fluorescence imaging.

Methods

Forty dogs with pulmonary masses were included, all of which underwent surgical treatment. ICG fluorescence imaging was performed on pulmonary masses before lobectomy and the resection margins after lobectomy. In addition, ICG fluorescence of the excised masses and lymph nodes was evaluated in the shaded box. The fluorescence findings were compared with the histopathological diagnosis.

Results

Of 44 nodules resected from 40 dogs, 32 nodules were histopathologically diagnosed as lung adenocarcinoma, five were histiocytic sarcoma, three were undifferentiated sarcoma, two were malignant epithelial tumor metastases, one was carcinosarcoma, and one was a non-neoplastic lesion. Fluorescence was observed in all nodules. In addition to the main lesion, other fluorescent nodules were found in four dogs. Regarding the diagnostic accuracy of complete resection based on ICG fluorescence, the sensitivity was 67.7% and the specificity was 60.0%. The sensitivity and specificity of ICG fluorescence for the diagnosis of lymph node metastasis were 100 and 75.0%, respectively.

Conclusions

ICG fluorescence imaging might be a useful intraoperative diagnostic method to identify the location of tumors and lymph node metastasis, but not to evaluate complete tumor resection, in dogs with pulmonary malignant tumors.

Novel color fluorescence imaging for sentinel lymph node detection in oral and oropharyngeal cancer

AIM

Fluorescence imaging (FI) using indocyanine green (ICG) is a noteworthy alternative technique for sentinel lymph node (SLN) detection without radiation exposure in oral cavity and oropharynx cancer. However, conventional FI is monochrome, so the visibility is limited. This study assessed whether color FI using the HyperEye Medical System (HEMS) is feasible as an alternative for SLN detection.

METHODS

Patients with previously untreated cT1-2N0 oral or oropharyngeal cancer who were to undergo primary tumor resection and elective neck dissection (END) in our hospital were enrolled from November 2012 to March 2016. The patients underwent SLN detection for biopsy via the HEMS following the injection of ICG solution around the primary lesion before neck dissection. The visibility and the diagnostic accuracy of the imaging were evaluated.

RESULTS

SLNs were visualized in all eight cases; however, transcutaneous fluorescence detection was not observed in all cases. Utilizing color mode imaging simplified harvest by clearly discriminating SLNs from surrounding structures, while the monochrome mode proved to be more sensitive for detection. Two cases showed occult metastases on both sentinel and regional nodes. The identification and false negative rates were 100% and 0%, respectively. There were no complications incurred due to this method.

CONCLUSION

Our results suggest that color FI with the HEMS allows for the accurate and safe harvest of SLNs with a preparatory skin incision. Although there is room for improvement of sensitivity, this easy-to-handle procedure might provide the potential to expand the role of the ICG method for SLN detection in head and neck cancer.

Use of indocyanine green for sentinel lymph node biopsy in melanoma

Sentinel lymph node (SLN) biopsy for cutaneous melanoma is a critical part of designing therapy for the skin malignancy. A retrospective review of 54 patients with cutaneous melanoma who underwent SLN biopsy guided by both radiotracer injection and indocyanine green (ICG) fluorescent dye compared the accuracy of identifying the SLN using each method. Patients were injected preoperatively with radiotracer at the site of the primary melanoma and intraoperatively with 2.5 mg of ICG. The detection of the SLN was compared between the two methods. Patients were followed to determine local recurrence and survival from 5 months to 4 years. ICG and radiotracer identified the SLN in 52 of 54 patients. In those patients who mapped, 52 of 52 showed mapping to the same node or nodes. The rate of cancer involvement in the identified node was 19.2% for both techniques. There was no difference in recurrence or survival between the two methods of SLN identification in short follow-up. In conclusion, ICG injection and mapping to identify SLN in cutaneous melanoma is confirmatory for radiotracer mapping and in the future may be an accurate and less costly method for SLN biopsy in cutaneous melanoma.

[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.

The primary application of indocyanine green fluorescence imaging in surgical oncology

Background

Indocyanine green (ICG) is a nontoxic, albumin-bound, liver-metabolized fluorescent iodide dye that has been widely utilized in clinical applications since the mid-1950s. However, after the 1970s, in-depth research on the fluorescence properties of ICG greatly expanded its application in the medical field.

Methods

In our mini-review, we searched the relevant literature on common oncology surgeries from PubMed, including lung cancer, breast cancer, gastric cancer, colorectal cancer, liver cancer, and pituitary tumors, using keywords such as indocyanine green, fluorescence imaging technology, and near-infrared fluorescence imaging. In addition, the application of targeted ICG photothermal technology in tumor therapy is briefly mentioned.

Results

In this mini-review, we analyzed studies on ICG fluorescence imaging in common surgical oncology and offered a thorough analysis of each form of cancer or tumor.

Conclusion

ICG has demonstrated significant potential in the detection and treatment of tumors in current clinical practice, although many applications are still in the preliminary stages, and multicenter studies are still required to more precisely define its indications, effectiveness, and safety.

Innovative experimental animal models for real-time comparison of antithrombogenicity between two oxygenators using dual extracorporeal circulation circuits and indocyanine green fluorescence imaging

BACKGROUND

Antithrombogenicity of extracorporeal membrane oxygenation (ECMO) devices, particularly oxygenators, is a current problem, with numerous studies and developments underway. However, there has been limited progress in developing methods to accurately compare the antithrombogenicity of oxygenators. Animal experiments are commonly conducted to evaluate the antithrombogenicity of devices; however, it is challenging to maintain a steady experimental environment. We propose an innovative experimental animal model to evaluate different devices in a constant experimental environment in real-time.

METHODS

This model uses two venous-arterial ECMO circuits attached to one animal (one by jugular vein and carotid artery, one by femoral vein and artery) and real-time assessment of thrombus formation in the oxygenator by indocyanine green (ICG) fluorescence imaging. Comparison studies were conducted using three pigs: one to compare different oxygenators (MERA vs. CAPIOX) (Case 1), and two to compare antithrombotic properties of the oxygenator (QUADROX) when used under different hydrodynamic conditions (continuous flow vs. pulsatile flow) (Cases 2 and 3).

RESULTS

Thrombi, visualized using ICG imaging, appeared as black dots on a white background in each oxygenator. In Case 1, differences in the site of thrombus formation and rate of thrombus growth were observed in real-time in two oxygenators. In Case 2 and 3, the thrombus region was smaller in pulsatile than in continuous conditions.

CONCLUSIONS

We devised an innovative experimental animal model for comparison of antithrombogenicity in ECMO circuits. This model enabled simultaneous evaluation of two different ECMO circuits under the same biological conditions and reduced the number of sacrificed experimental animals.

Single Camera-Based Dual-Channel Near-Infrared Fluorescence Imaging system

In this study, we propose a single camera-based dual-channel near-infrared (NIR) fluorescence imaging system that produces color and dual-channel NIR fluorescence images in real time. To simultaneously acquire color and dual-channel NIR fluorescence images of two fluorescent agents, three cameras and additional optical parts are generally used. As a result, the volume of the image acquisition unit increases, interfering with movements during surgical procedures and increasing production costs. In the system herein proposed, instead of using three cameras, we set a single camera equipped with two image sensors that can simultaneously acquire color and single-channel NIR fluorescence images, thus reducing the volume of the image acquisition unit. The single-channel NIR fluorescence images were time-divided into two channels by synchronizing the camera and two excitation lasers, and the noise caused by the crosstalk effect between the two fluorescent agents was removed through image processing. To evaluate the performance of the system, experiments were conducted for the two fluorescent agents to measure the sensitivity, crosstalk effect, and signal-to-background ratio. The compactness of the resulting image acquisition unit alleviates the inconvenient movement obstruction of previous devices during clinical and animal surgery and reduces the complexity and costs of the manufacturing process, which may facilitate the dissemination of this type of system.

Safety and usefulness of fluorescence imaging using methylene blue as a fluorophore in a Japanese population with hepatobiliary and pancreatic diseases: A phase I study

BACKGROUND

Methylene blue (MB) has been used to treat methemoglobinemia. Recently, a fluorescence imaging technique using MB as a fluorophore was used in several region but still not in hepatobiliary and pancreatic surgery; thus, information on the safety of intraoperative fluorescence imaging using MB in a healthy Japanese population is lacking. We aimed to evaluate the usefulness of MB fluorescence imaging in patients undergoing hepatobiliary and pancreatic surgery and the safety of intraoperative administration of MB in patients without methemoglobinemia.

METHODS

Eighteen patients undergoing hepatobiliary and pancreatic surgery were enrolled. We developed and used a fluorescence imaging system to visualize MB as fluorescence. The fluorescence intensity of the blood vessels, tumors, liver, and intestine were measured. The primary endpoint was the ability of the MB fluorescence imaging to visualize vessels and tumors with fluorescence. The secondary endpoint was the safety of fluorescence imaging using MB in patients without methemoglobinemia.

RESULTS

For the 18 patients undergoing MB fluorescence imaging, no intraoperative and postoperative complications related to MB administration occurred. Seventeen patients (94%) successfully visualized the target object as fluorescence by MB fluorescence imaging, including 100% of neuroendocrine tumors (four tumors) and peripancreatic vessels (n = 13).

CONCLUSION

The administration of MB and application of fluorescence imaging using MB can visualize blood vessels and pancreatic neuroendocrine neoplasms. And it also showed the safety of using MB as a fluorophore in Japanese patients without methemoglobinemia.

Clinical impact of near-infrared fluorescence imaging with indocyanine green on surgical treatment for hepatic masses in dogs

BACKGROUND

Near-infrared fluorescence imaging using indocyanine green (ICG) is clinically applied to intraoperatively identify hepatic masses in humans. In addition, it is reported to be effective for assessing complete resection in human hepatocellular carcinoma (HCC). However, there is limited information on ICG fluorescence imaging for canine HCC, and its clinical usefulness is still unclear. Therefore, the purpose of this study was to evaluate the intraoperative identification and status of surgical margin for canine hepatic masses using near-infrared ICG fluorescence imaging. This clinical study included 104 dogs with hepatic masses. Between 12 and 24 h prior to surgery, ICG solution was injected intravenously at a dose of 0.5 mg/kg. The fluorescence intensity and pattern of each hepatic mass was investigated using an infrared camera before resection. After resection, the fluorescence intensity of the resection margin was also investigated. The resected masses were histopathologically diagnosed and compared using ICG fluorescence imaging.

RESULTS

One hundred and twenty-two masses obtained from 104 dogs included 76 HCCs, 16 hepatocellular adenomas, 12 focal nodular hyperplasias, and 18 other lesions. Of the 122 masses, 106 (94 partial, 9 whole, and 3 ring fluorescence patterns), 7, and 9 masses showed increased, the same, or decreased fluorescence compared to the normal liver tissue, respectively. The fluorescence intensity and pattern were not significantly related to the histopathological diagnosis. The sensitivity and specificity of the margin evaluation in the 47 dogs were 100% and 77.3%, respectively. The median survival times in cases of HCC with complete and incomplete resection were 914 and 254 days, respectively. The median survival time of patients with a complete resection was significantly longer than that of patients with a incomplete resection (p = 0.043).

CONCLUSION

ICG fluorescence imaging has potential clinical value for the identification and margin evaluation of canine hepatic masses. Although it is difficult to use fluorescence imaging for the differential diagnosis of liver tumours, it may be useful for assessing complete resection in cases of hepatic masses demonstrating increased fluorescence in dogs, and complete resection of HCC could have a survival benefit.

Stannous colloid mixed with indocyanine green as a tracer for sentinel lymph node navigation surgery

The combined use of a vital dye and radioactive colloid reportedly performs better in detecting sentinel lymph nodes (SLNs) for cancers than the use of either of them alone. However, especially for gastric cancer, two endoscopic procedures are required to administer these two tracers, which burdens the patients and practitioners. Here we propose the use of stannous colloid (SnC) mixed with indocyanine green (ICG) as a new mixed tracer (SnC-ICG); its characteristics were investigated in vivo and in vitro to estimate its usefulness for SLN navigation. The tracers were administered to rats and the accumulation of radioactivity and/or near-infrared fluorescence were evaluated in the regional lymph nodes (LNs) using single positron emission computed tomography and near-infrared fluorescence imaging, respectively. SnC-ICG showed significantly better clearance from the injection site and better migration to primary LNs than the single administration of SnC or ICG aqueous solution. SnC-ICG demonstrated a wide particle size variability, stabilized to 1200-nm upon the addition of albumin in vitro; These properties could contribute to its behavior in vivo. The use of SnC-ICG could contribute better performance to detect SLNs for gastric cancer with less burden on both patients and medical practitioners.

Transcutaneous sentinel lymph node detection in cutaneous melanoma with indocyanine green and near-infrared fluorescence: A diagnostic sensitivity study

Sentinel lymph node (SLN) biopsy with preoperative radiocolloid-based lymphoscintigraphy and blue dye injection is considered the standard procedure for staging nodal metastases in early-stage cutaneous melanoma patients with clinically uninvolved lymph nodes. While this combination renders good accuracy in SLN detection, radiation exposure and the frequent allergic reactions to the blue dye are considered drawbacks of this technique. Indocyanine green (ICG) is a water-soluble fluorescent dye that can be identified through near-infrared fluorescence imaging (NIRFI). The aim of this prospective diagnostic sensitivity study was to assess the feasibility of ICG and NIRFI to identify SLNs in melanoma transcutaneously ("before skin incision") and to analyze the various factors influencing detection rate, in comparison to lymphoscintigraphy. This study included 93 patients undergoing SLN biopsy for cutaneous melanoma. The region and the number of the SLNs identified with lymphoscintigraphy and with ICG were recorded. Patients' characteristics, as well as tumor details were also recorded preoperatively. One hundred and ninety-four SLNs were identified through lymphoscintigraphy. The sensitivity of ICG for transcutaneous identification of the location of the SLNs was 96.1% overall, while the sensitivity rate for the number of SLNs was 79.4%. Gender and age did not seem to influence detection rate, but a body mass index >30 kg/m2 was associated with a lower identification rate of the number of SLNs (P = .045). Transcutaneous identification of SLNs through ICG and NIRFI technology is a feasible technique that could potentially replace in selected patients the standard SLN detection methodology in cutaneous melanoma.

Lymphaticovenular Anastomosis: Superficial Venous Anatomical Approach

Background  Lymphaticovenular anastomosis (LVA) is an effective, functional treatment for limb lymphedema. This study reports an alternative surgical approach to lymphedema treatment without the use of indocyanine green mapping.

Methods  A retrospective analysis was performed on 29 consecutive lymphedema patients who underwent LVAs from January 2015 to December 2020, whereby incisions were made along the anatomy of the superficial venous systems in both upper and lower extremities around the joint areas. The evaluation included qualitative assessments and quantitative volumetric analyses.

Result  The mean number of anastomoses was 3.07, and the operative time was 159.55 minutes. Symptom improvement was recorded in 86.21% of the patients, with a mean volume reduction of 32.39%. The lymphangitis episodes decreased from 55.17% before surgery to 13.79% after surgery, and the median number of lymphangitis episodes per year decreased from 1 before surgery to 0 after surgery.

Conclusions  The superficial venous anatomical approach is an easy way to start a lymphedema practice using LVA without other advanced surgical equipment. With this reliable technique, microsurgeons can perform LVA procedures and achieve good results.

Optimal settings of near-infrared fluorescence imaging with indocyanine green for intraoperative detection of lymph node metastasis in esophageal cancer

Lymphatic flow mapping using near-infrared fluorescence (NIR) imaging with indocyanine green (ICG) has been used for intraoperative diagnosis of lymph node metastasis (LNM) in various cancers. Accurate prediction of LNM intraoperatively may allow minimization of the extent of lymphadenectomy. However, a consistent method and diagnostic ability, allowing application of NIR-guided lymphatic flow mapping to esophageal cancer (EC), have not been established due to the multidirectional and complex characteristics of lymphatic flow in the esophagus. Herein, we present a novel NIR-guided surgical technique for predicting lymph node stations potentially containing LNM in EC with high diagnostic accuracy derived from appropriately adjusting the ICG injection setting.

Short-term and long-term outcomes of indocyanine green for sentinel lymph node biopsy in early-stage breast cancer

Background

Indocyanine green (ICG) is becoming a frequently used sentinel lymph node (SLN) tracer of breast cancer in China. However, there is still a lack of data on its safety. We reported the clinical outcome of ICG as a tracer of SLN over a median 67-month follow-up period to evaluate its feasibility in clinically node-negative patients with breast cancer.

Methods

A total of 194 consecutive patients underwent sentinel lymph node biopsy (SLNB) with ICG, radioisotopes (RI) and methylene blue (MB), or with ICG and MB. The SLN mapping data by each tracer was recorded, and safety outcomes were analyzed through follow-up.

Results

With the triad mapping (N = 44), the identification rate of SLN by ICG was 95.5%, slightly higher than that of MB (86.4%) and comparable with RI (95.5%) and combined methods (95.5%, 100%) (p = 0.068). Analysis of all candidates (N = 194) demonstrated that the identification rate of SLN by ICG or by ICG and MB was 99%, significantly higher than that by MB (92.8%) (p < 0.0001). No tracer-related allergic reaction and permanent skin staining of ICG were observed. Local disease progression was reported in 2 of the 194 patients at the ipsilateral axilla. After remedial axillary lymph node dissection, no disease progression was detected at follow-up.

Conclusions

ICG as an SLN tracer is more accurate than MB and comparable to the combined methods and has good clinical safety. ICG can be considered a useful supplement or suitable alternative to traditional tracers.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-022-02719-7.

Added value of indocyanine green fluorescence imaging in liver surgery

Recently, indocyanine green (ICG) fluorescence imaging has been widely used as a substitute for cholangiography in hepatobiliary surgery, to detect hepatic tumors, for accurate anatomical hepatectomy, and to increase the safety and accuracy of minimally invasive (laparoscopic and robotic) hepatectomy. The clinical relevance of this method has been increasing gradually, as new procedures develop in this field. Various important roles and the latest added value of ICG fluorescence imaging in liver surgery are discussed in this report.

Development of Intraoperative Near-Infrared Fluorescence Imaging System Using a Dual-CMOS Single Camera

We developed a single-camera-based near-infrared (NIR) fluorescence imaging device using indocyanine green (ICG) NIR fluorescence contrast agents for image-induced surgery. In general, a fluorescent imaging system that simultaneously provides color and NIR images uses two cameras, which is disadvantageous because it increases the imaging head of the system. Recently, a single-camera-based NIR optical imaging device with quantum efficiency partially extended to the NIR region was developed to overcome this drawback. The system used RGB_NIR filters for camera sensors to provide color and NIR images simultaneously; however, the sensitivity and resolution of the infrared images are reduced by 1/4, and the exposure time and gain cannot be set individually when acquiring color and NIR images. Thus, to overcome these shortcomings, this study developed a compact fluorescent imaging system that uses a single camera with two complementary metal-oxide semiconductor (CMOS) image sensors. Sensitivity and signal-to-background ratio were measured according to the concentrations of ICG solution, exposure time, and camera gain to evaluate the performance of the imaging system. Consequently, the clinical applicability of the system was confirmed through the toxicity analysis of the light source and in vivo testing.

Fluorescent Tracers for In Vivo Imaging of Lymphatic Targets

The lymphatic system continues to gain importance in a range of conditions, and therefore, imaging of lymphatic vessels is becoming more widespread for research, diagnosis, and treatment. Fluorescent lymphatic imaging offers advantages over other methods in that it is affordable, has higher resolution, and does not require radiation exposure. However, because the lymphatic system is a one-way drainage system, the successful delivery of fluorescent tracers to lymphatic vessels represents a unique challenge. Each fluorescent tracer used for lymphatic imaging has distinct characteristics, including size, shape, charge, weight, conjugates, excitation/emission wavelength, stability, and quantum yield. These characteristics in combination with the properties of the target tissue affect the uptake of the dye into lymphatic vessels and the fluorescence quality. Here, we review the characteristics of visible wavelength and near-infrared fluorescent tracers used for in vivo lymphatic imaging and describe the various techniques used to specifically target them to lymphatic vessels for high-quality lymphatic imaging in both clinical and pre-clinical applications. We also discuss potential areas of future research to improve the lymphatic fluorescent tracer design.

Efficacy and Safety of Mitoxantrone Hydrochloride Injection for Tracing Axillary Sentinel Nodes in Breast Cancer: A Self-Controlled Clinical Trial

Background

Mitoxantrone hydrochloride injection for tracing (MHI), a new strategy to identify lymph nodes, has not been tested for axillary node staging in breast cancer. This multicenter, self-controlled, non-inferiority trial aimed to evaluate MHI’s efficacy and safety in sentinel lymph node biopsy (SLNB).

Methods

The trial was conducted across seven hospitals from December 2019 to December 2020. Patients with early-stage breast cancer received MHI and technetium-99m (99mTc) during the surgery. Sentinel node detection rates were compared between MHI and 99mTc to evaluate non-inferiority and concordance. Non-inferiority was valid if the lower limit of the 95% CI of sentinel node relative detection rate difference was ≥−5%.

Results

SLN relative detection rate of MHI was 97.31% (362/372). Of the SLNs, 79.69% (871/1093) were co-detected by both tracers. Of the patients, 4.13% (16/387) had adverse events and recovered during the follow-up.

Conclusions

MHI is a lymphatic tracer with comparable efficacy to radionuclides and can be used alone or in combination with radioactive substances for SLNB.

Clinical Trial Registration

http://www.chinadrugtrials.org.cn, CTR20192435.

Mouthwash as a non-invasive method of indocyanine green delivery for near-infrared fluorescence dental imaging

SIGNIFICANCE

X-ray imaging serves as the mainstream imaging in dentistry, but it involves risk of ionizing radiation.

AIM

This study presents the feasibility of indocyanine green-assisted near-infrared fluorescence (ICG-NIRF) dental imaging with 785-nm NIR laser in the first (ICG-NIRF-I: 700 to 1000 nm) and second (ICG-NIRF-II: 1000 to 1700 nm) NIR wavelengths.

APPROACH

Sprague Dawley rats with different postnatal days were used as animal models. ICG, as a fluorescence agent, was delivered to dental structures by subcutaneous injection (SC) and oral administration (OA).

RESULTS

For SC method, erupted and unerupted molars could be observed from ICG-NIRF images at a short imaging time (<1  min). ICG-NIRF-II could achieve a better image contrast in unerupted molars at 24 h after ICG injection. The OA could serve as a non-invasive method for ICG delivery; it could also cause the glow-in-dark effect in unerupted molars. For erupted molars, OA can be considered as mouthwash and exhibits outstanding performance for delivery of ICG dye; erupted molar structures could be observed at a short imaging time (<1  min) and low ICG dose (0.05  mg  /  kg).

CONCLUSIONS

Overall, ICG-NIRF with mouthwash could perform in-vivo dental imaging in two NIR wavelengths at a short time and low ICG dose.

Intraoperative Tumor Identification During Laparoscopic Distal Gastrectomy: a Novel Fluorescent Clip Marking Versus Metal Clip Marking and Intraoperative Gastroscope

BACKGROUND

In complete laparoscopic distal gastrectomy, the gastric resection line is difficult to determine due to a lack of tactile sensation. The use of intraoperative gastroscopy and intraoperative radiography has been reported, but the burden on personnel and technical complexity present impediments. In our department, based on lesion extent determined with preoperative gastroscopy, a fluorescent clip is used to mark the oral side of the lesion, which is resected after confirmation with a fluorescent laparoscopic system. In this study, we investigated the efficacy of fluorescent clip marking (FCM) in achieving an accurate resection line and reducing the operative time.

METHODS

Fifty-six patients with gastric cancer who underwent complete laparoscopic distal gastrectomy from January 2018 to March 2021 were divided into two groups: the FCM group (n = 32) and the conventional metal clip marking and intraoperative gastroscopy (MCMG) group (n = 24). Short-term outcomes, including the resection margins, gastric resection time, and operative time, were compared and examined.

RESULTS

The fluorescent clips were visible in all cases, and all stumps were negative according to permanent preparations. The operative times for FCM and MCMG were 350 (216-533) vs. 373.5 (258-651) min, respectively, with no significant difference (p = 0.316), while the gastric resection times were 636.5 (321-2572) vs. 1457.5 (843-4973) s, respectively, and were significantly shorter in the FCM group (p < 0.0001).

CONCLUSIONS

FCM shortened the gastric resection time and could possibly shorten the operative time. FCM is feasible and safe and can potentially be used as a tumor-marking agent to determine accurate surgical resection lines.

CLINICAL TRIAL REGISTRATION

Examination of Gastric Cancer, Research Ethics Committee of the Kawaguchi Municipal Medical Centre (Saitama, Japan), approval number: 2019-33. https://kawaguchi-mmc.org/wp-content/uploads/clinicalresearch-r02.pdf.