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

Novel quinoline-based fluorescent bioimaging probe, KSNP117, for sentinel lymph node mapping

Fluorescent imaging agents with biocompatibility and high sensitivity are urgently required for the accurate detection of sentinel lymph nodes (SLNs). Herein, we report the design of a novel quinoline-based fluorescent probe, designated KSNP117, which can be applied as a biomedical imaging agent in the sensitive and quantitative detection of SLNs. KSNP117 exerted no adverse effects on the proliferation of ovary and immune cells and also showed excellent serum stability with photo-brightening effects. In vivo fluorescent imaging revealed the accumulation of KSNP117 in the SLNs of nude mice within 10 min post injection, without in vivo toxicity, which was consistent with the findings of ex vivo imaging. These results support the potential of KSNP117 as a promising lymphatic tracer for biomedical imaging applications.

The Use of Indocyanine Green Fluorescence Angiography in Pediatric Surgery: A Systematic Review and Narrative Analysis

Purpose: Indocyanine green fluorescence angiography (ICG-FA) is a validated non-invasive imaging technique used to assess tissue vascularization and guide intraoperative decisions in many surgical fields including plastic surgery, neurosurgery, and general surgery. While this technology is well-established in adult surgery, it remains sparsely used in pediatric surgery. Our aim was to systematically review and provide an overview of all available evidence on the perioperative use of indocyanine green fluorescence angiography in pediatric surgical patients. Methods: We conducted a systematic review with narrative synthesis in conformity with the PRISMA guidelines using PubMed, Medline, All EBM Reviews, EMBASE, PsycINFO, and CINAHL COMPLETE databases to identify articles describing the perioperative use of ICG-FA in pediatric patients. Two independent authors screened all included articles for eligibility and inclusion criteria. We extracted data on study design, demographics, surgical indications, indocyanine green dose, and perioperative outcomes. We developed a risk of bias assessment tool to evaluate the methodological quality of included studies. Results: Of 1,031 articles retrieved, a total of 64 articles published between 2003 and 2020 were included reporting on 664 pediatric patients. Most articles were case reports and case series (n = 36; 56%). No adverse events related to ICG-FA were reported in the included articles. Risk of bias was high. We did not conduct a meta-analysis given the heterogeneous nature of the populations, interventions, and outcome measures. A narrative synthesis is presented. Conclusion: Indocyanine green fluorescence angiography is a safe imaging technology and its use is increasing rapidly in pediatric surgical specialties. However, the quality of evidence supporting this trend currently appears low. Case-control and randomized trials are needed to determine the adequate pediatric dose and to confirm the potential benefits of ICG-FA in pediatric surgical patients. Systematic Review Registration: This study was registered on Prospero a priori, identifier: CRD42020151981.

Comparisons of ICG-fluorescence with conventional tracers in sentinel lymph node biopsy for patients with early-stage breast cancer: A meta-analysis

Radioisotopes (RI) and blue dye (BD) are routinely used markers for staining during sentinel lymph node biopsy (SLNB) in breast cancer. Compared with traditional tracers, tracer performance of indocyanine green (ICG) has been controversial. A total of 21 studies were selected from the PubMed, EMBASE and Cochrane Library databases. Detection ability was judged based on four endpoints: i) The identification rate (IR) of the patients; ii) the IR of the sentinel lymph nodes (SLNs); iii) the IR of the positive SLNs; and iv) the false negative rate (FNR). Compared with BD, ICG was superior in terms of the IR of the patients [odds ratio (OR)=7.17; 95% CI, 3.98-12.94), the IR of the SLNs (OR=8.84; 95% CI, 6.71-11.66) and FNR (OR=0.20; 95% CI, 0.08-0.48) using a fixed-effects model. There was a significant difference in both the IR of the positive SLNs (OR=21.32; 95% CI, 2.84-160.14) and FNR (OR=0.46; 95% CI, 0.23-0.91) in the ICG vs. RI group. Furthermore, when using ICG at the recommended dose, a significant difference was found in the IR of the patients (OR=1.77; 95% CI, 1.09-2.85) and the IR of the SLNs (OR=21.62; 95% CI, 5.23-89.43) using a fixed-effects model. In the ICG vs. BD combined with RI group, there were no differences in either the IR of the patients (OR=5.10; 95% CI, 0.24-107.48) or the IR of SLNs (OR=5.10; 95% CI, 0.60-256.66). In conclusion, ICG was a better tracer compared with BD or RI alone and was not a worse tracer compared with BD combined with RI. The use of the recommended dose of ICG had an improved tracer effect. ICG is expected to be widely used in SLNB in view of its clinical advantages.

Personalizing Conservative Lymphedema Management Using Indocyanine Green-Guided Manual Lymphatic Drainage

Background: The Australian Lymphoedema Education, Research and Treatment Program (ALERT) at Macquarie University in Sydney, Australia is one of the flagship programs of Australia's first fully integrated academic health sciences centre, MQ Health. The aim of this study was to describe our findings of compensatory drainage demonstrated by indocyanine green (ICG) lymphography in cancer-related upper and lower limb lymphedema and how this may be translated into clinical practice. Methods and Results: Retrospective data from 339 patients aged between 18 and 90 years with secondary cancer-related unilateral or bilateral lymphedema of the upper or lower limb who underwent ICG lymphography assessment at the ALERT clinic between February 2017 and March 2020 were analyzed. In patients with upper limb lymphedema, the ipsilateral axilla was the most frequent drainage region (74.9%), followed by clavicular (41.8%) and parasternal (11.3%). For patients with mild upper limb lymphedema, 94.4% drained to the ipsilateral axilla. No patients drained to the ipsilateral inguinal region. For lower limb lymphedema, drainage to the ipsilateral inguinal was most common (52.3%), followed by contralateral inguinal (30.7%), popliteal (26.1%), and gluteal (21.6%) regions. Three main patterns of superficial lymphatic compensation were identified based on which anatomical structure carried lymph fluid. Manual lymphatic drainage (MLD) was used to facilitate movement of the dye. A light/effleurage technique was sufficient to move the dye through patent lymphatic vessels; a slow and firmer technique was required to move the dye through areas of bridging dermal backflow. Conclusion: The introduction of ICG lymphography to our program and its use in guiding personalized conservative management plans, including facilitative MLD techniques, has translated into clinical practice and changed research and educational priorities within the ALERT program.

Monte Carlo Modeling of Shortwave-Infrared Fluorescence Photon Migration in Voxelized Media for the Detection of Breast Cancer

Recent progress regarding shortwave-infrared (SWIR) molecular imaging technology has inspired another modality of noninvasive diagnosis for early breast cancer detection in which previous mammography or sonography would be compensated. Although a SWIR fluorescence image of a small breast cancer of several millimeters was obtained from experiments with small animals, detailed numerical analyses before clinical application were required, since various parameters such as size as well as body hair differed between humans and small experimental animals. In this study, the feasibility of SWIR was compared against visible (VIS) and near-infrared (NIR) region, using the Monte Carlo simulation in voxelized media. In this model, due to the implementation of the excitation gradient, fluorescence is based on rational mechanisms, whereas fluorescence within breast cancer is spatially proportional to excitation intensity. The fluence map of SWIR simulation with excitation gradient indicated signals near the upper surface of the cancer, and stronger than those of the NIR. Furthermore, there was a dependency on the fluence signal distribution on the contour of the breast tissue, as well as the internal structure, due to the implementation of digital anatomical data for the Visible Human Project. The fluorescence signal was observed to become weaker in all regions including the VIS, the NIR, and the SWIR region, when fluorescence-labeled cancer either became smaller or was embedded in a deeper area. However, fluorescence in SWIR alone from a cancer of 4 mm diameter was judged to be detectable at a depth of 1.4 cm.

One-Step, Rapid, 18F-19F Isotopic Exchange Radiolabeling of Difluoro-dioxaborinins: Substituent Effect on Stability and In Vivo Applications

The β-diketone moiety is commonly present in many anticancer drugs, antibiotics, and natural products. We describe a general method for radiolabeling β-diketone-bearing molecules with fluoride-18. Radiolabeling was carried out via ¹⁸F-¹⁹F isotopic exchange on nonradioactive difluoro-dioxaborinins, which were generated by minimally modifying the β-diketone as a difluoroborate. Radiochemistry was one-step, rapid (<10 min), and high-yielding (>80%) and proceeded at room temperature to accommodate the half-life of F-18 (t_1/2 = 110 min). High molar activities (7.4 Ci/μmol) were achieved with relatively low starting activities (16.4 mCi). It was found that substituents affected both the solvolytic stability and fluorescence properties of difluoro-dioxaborinins. An F-18 radiolabeled difluoro-dioxaborinin probe that was simultaneously fluorescent showed sufficient stability for in vivo positron emission tomography (PET)/fluorescence imaging in mice, rabbits, and patients. These findings will guide the design of probes with specific PET/fluorescence properties; the development of new PET/fluorescence dual-modality reporters; and accurate in vivo tracking of β-diketone molecules.

Lymphovenous Anastomosis for Morbidly Obese Patients with Lymphedema

Although patients with obesity-induced lymphedema can be treated by weight loss therapy, they find it difficult to lose the required amount of weight. The aims of this study were to clarify the characteristics of the lymphatic vessels in patients with obesity-induced lymphedema and to determine the feasibility and efficacy of lymphovenous anastomosis (LVA) in these patients.

Methods

Twenty-two patients (44 edematous lower limbs) with a body mass index (BMI) >35 kg/m² (obese group) and 91 patients with lymphedema (141 edematous lower limbs) and BMI <25 kg/m² were enrolled as a control group (nonobese group) and underwent LVA. The diameter and depth of lymphatics and the effect of LVA were compared.

Results

Lymphatics were detectable within 10-mm depth in the nonobese group and the obese group (3.0 ± 1.4 mm versus 3.5 ± 2.1 mm; P < 0.01). The lymphatic diameter was significantly greater in the obese group than in the nonobese group (0.79 ± 0.30 mm versus 0.54 ± 0.22 mm; P < 0.01). There was no significant difference in the rate of improvement in lymphedema after LVA between the nonobese group (9.1% ± 9.2%) and the obese group (8.9% ± 7.3%; P = 0.84). There was no correlation between the improvement rate of lymphedema and that of BMI in the obese group (P = 0.57).

Conclusions

LVA is a feasible procedure even in morbidly obese patients. Considering that substantial weight loss is a difficult and time-consuming task for patients, LVA combined with not gaining weight is a good option for these patients.

Near-Infrared Fluorescent Image-Guided Lymphatic Mapping in Esophageal Squamous Cell Carcinoma

BACKGROUND

Recently, the feasibility of near-infrared (NIR) image-guided sentinel lymph node (SLN) mapping has been tested in patients with gastrointestinal cancer. The aim of this study is to investigate whether SLN mapping can be used to identify mediastinal lymph node metastases during minimally invasive esophagectomy and explore the lymphatic drainage pattern of esophageal squamous cell carcinoma (ESCC) using NIR fluorescent imaging.

PATIENTS AND METHODS

A total of 21 patients diagnosed with cT1-3 stage ESCC were enrolled. Patients received submucosal injection of indocyanine green diluted with sodium chloride (0.9%) at the start of the esophagectomy procedure followed by NIR mapping.

RESULTS

Thoracoscopic-assisted McKeown esophagectomy with NIR imaging was successfully performed in all patients. The detection rate and number of NIR+ lymph nodes were 95.2% (20/21) and 4.0 (2.0-6.5), respectively. The accuracy, false-negative rates, and negative predictive value were 100% (10 of 10 cases), 0% (0 of 4), and 100% (6 of 6), respectively, for pT1/T2 diseases; and 80.0% (8 of 10), 40% (2 of 5), and 71.4% (5 of 7), respectively, for pT3 diseases. The NIR+ region was the most commonly detected in the right recurrent laryngeal nerve (80%), and the NIR+ region was identified in the upper mediastinal zone in 20 patients.

CONCLUSIONS

Evaluation of the lymphatic drainage pattern and the application of sentinel lymph node in ESCC with real-time NIR imaging could be effective, especially in pT1/2 disease. NIR imaging-guided SLN navigation appears to be a clinically beneficial less-invasive method for treating ESCC.

Adult axillary lymphangioma removal using indocyanine green fluorescence imaging system: A case report

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Adult cystic lymphangioma is extremely rare.

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Diagnosis of lymphangioma is relatively easy based on the clinical image findings.

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Complete surgical excision is the most effective treatment for lymphangioma.

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The ICG fluorescence imaging system is very useful for performing complete excision.

Introduction

Lymphangiomas are benign cystic tumors which arise from congenital malformations of the lymphatic system and are extremely rare in adulthood. We report a case of adult lymphangioma of the axilla that was removed after identifying the feeding lymphatic vessel using an indocyanine green (ICG) fluorescence imaging system.

Presentation of case

A 35-year old woman presented to our hospital with a rapidly growing mass on her left axilla. She had been pregnant once before and delivered at 34 years of age. Mammography, ultrasonography, and magnetic resonance imaging revealed a tumor that consisted of multiple cysts, which led to a diagnosis of cystic lymphangioma. The ICG fluorescence imaging system indicated that only one lymphatic vessel, which was completely removed with ligation of the feeding lymphatic vessel, was flowing to the tumor. An immunohistological study demonstrated that the cystic endothelia were positive for podoplanin (D2-40), a marker of lymphatic vessels.

Discussion

In addition to congenital factors, mechanical obstruction to lymphatic vessels by an external force, such as trauma or congestion of the lymphatic flow caused by increasing venous pressure during pregnancy or delivery might lead to lymphangioma in adulthood. Therefore, our patient’s pregnancy and delivery one year prior to discovery of the tumor seems to be the cause of her lymphangioma.

Conclusion

Based on our findings, we recommend the complete excision to successfully treat adult-onset lymphangioma. We also suggest that visualization with ICG fluorescence imaging system is very useful for detecting the feeding lymphatic vessel and performing complete excision of the lymphangioma.

Multicolor fluorescence imaging using a single RGB-IR CMOS sensor for cancer detection with smURFP-labeled probiotics

A multicolor fluorescence imaging device was recently developed for image-guided surgery. However, conventional systems are typically bulky and function with two cameras. To overcome these issues, we developed an economical home-built fluorescence imaging device based on a single RGB-IR sensor that can acquire both color and fluorescence images simultaneously. The technical feasibility of RGB-IR imaging was verified ex vivo in chicken breast tissue using fluorescein isothiocyanate (FITC), cyanine 5 (Cy5), and indocyanine green (ICG) as fluorescent agents. The minimum sensitivities for FITC, Cy5, and ICG were 0.200 µM, 0.130 µM, and 0.065 µM, respectively. In addition, we validated the fluorescence imaging of this device in vitro during a minimally invasive procedure using smURFP-labeled probiotics, which emit a spectrum similar to that of Cy5. Our preliminary study of the ex vivo tissue suggests that Cy5 and ICG are good candidates for deep tissue imaging. In addition, the tumor-specific amplification process was visualized using cancer cells incubated with probiotics that had been labeled with a fluorescent protein. Our approach indicates the potential for in vivo screening of tumors in rodent tumor models.

Near-infrared fluorescent solid material for visualizing indwelling devices implanted for medical use

BACKGROUND

In clinical practice, various devices are implanted into the body for medical reasons. As X-ray fluoroscopy is necessary to visualize medical devices implanted into the body, the development of a less-invasive visualization method is highly desired. This study aimed to investigate the clinical applicability of our novel solid material that emits near-infrared fluorescence.

METHODS

We developed a solid resin material that emits near-infrared fluorescence. This material incorporates a near-infrared fluorescent pigment, with quantum yield ≥ 20 times than that of indocyanine green. It can be sterilized for medical treatment. This resin material is designed to be molded into a catheter and inserted into the body with an endoscope clip. In this preclinical experiment using a swine model, the resin material was embedded into the body of the swine and visualized with a near-infrared fluorescence camera system.

RESULTS

Endoscopic clips were placed in the mucosa of the stomach, esophagus, and large intestine, and the indwelling ureteral catheters were successfully visualized by near-infrared fluorescence laparoscopy.

CONCLUSIONS

We confirmed the tissue permeability of the fluorescence emitted by our novel near-infrared fluorescent material and the possibility of its clinical application. This material may allow visualization of devices embedded in the body.

The Utility of Indocyanine Green Angiography in the Assessment of Perfusion of Gastric Conduit and Proximal Esophageal Stump Against Visual Assessment in Patients Undergoing Esophagectomy: a Prospective Study

Post esophagectomy anastomotic leakage is a crucial factor in determining morbidity and mortality. Good vascularity of the gastric conduit is essential to avoid this complication. This prospective study compares the utility of intraoperative indocyanine green (ICG) fluorescence angiography and visual assessment in assessing the vascularity of gastric conduit and proximal esophageal stump in patients undergoing esophagectomy. Thirteen consecutive patients who underwent esophagectomy for carcinoma middle, lower third esophagus or gastro-esophageal junction from August 2019 to September 2019 were included. Three patients underwent laparoscopic-assisted transhiatal esophagectomy, ten thoraco-laparoscopic-assisted esophagectomy. Reconstruction was done by gastric pull-up via posterior mediastinal route. All patients underwent assessment of perfusion of gastric conduit and proximal esophageal stump by ICG angiography and by visual assessment based on inspection of the color, the palpation of warmth, pulse, and bleeding from the edges. Visual assessment revealed the tip of the gastric conduit was dusky and ischemic in 11 patients, pink and well perfused in two. ICG fluorescence imaging showed inadequate perfusion at the tip of conduit in 12 patients, adequate in one, overall requiring revision in 12 cases. There was a discrepancy in one patient where visual inspection showed adequate perfusion, but ICG disclosed poor vascularity requiring revision of the conduit's tip. Resection of the devitalized portion of the proximal esophageal stump was needed in 5 patients both by visual and by ICG assessment. The median time to appearance of blush from the time of injection of dye was 15 s (10 to 23 s). In all the cases, the pattern of blush was simultaneous, with the concurrent appearance of ICG blush in the gastric conduit and gastro-epiploic arcade. No anastomotic leaks were noted. Visual inspection of the gastric conduit vascularity can underestimate perfusion and hence can compromise resection of the devitalized part. ICG fluorescence imaging is an accurate and promising means to ascertain the vascularity of gastric conduit during an esophagectomy. But its utility needs to be validated in randomized trials.

Methylene Blue-Based Near-Infrared Fluorescence Imaging for Breast Cancer Visualization in Resected Human Tissues

Breast-conserving surgery is facing the challenge of objective tumor margin identification intraoperatively. Near-infrared fluorescence imaging would be an ideal approach to visualize tumor margins during surgeries. In this preliminary study, the feasibility of methylene blue-based near-infrared fluorescence imaging technique for breast cancer detection was assessed in resected human breast specimens after breast cancer surgeries. Thirty patients with breast cancer scheduled for surgical treatment were enrolled, including 10 patients with preoperative chemotherapy and 20 patients without. Each of them received an injection of 1 mg/kg methylene blue intravenously 3 hours before the surgery. Then, a home-developed methylene blue-specific near-infrared fluorescence imaging system was employed to image the resected breast tissues and identify the tumor by the fluorescence contrast. Specimens were taken for pathological examinations as the reference. There were no severe adverse events attributable to methylene blue. Of 20 patients, who did not receive preoperative chemotherapy, 16 exhibited fluorescent contrast on their resected tissues (signal-to-background ratio: 1.94 ± 0.71). In contrast, tumors were identified in 3 of 10 specimens from patients who underwent preoperative chemotherapy (signal-to-background ratio: 1.63 ± 0.38). A total of 35 tissues were sampled from 30 specimens. Besides 30 tumor samples, 5 more suspicious samples with fluorescence signal were confirmed to be benign hemorrhagic tissues. Therefore, a sensitivity of 0.63 and a positive predictive value of 0.79 were achieved by the methylene blue fluorescence imaging strategy. Here, we demonstrate the feasibility of using methylene blue fluorescence imaging to identify breast cancer. Preoperative chemotherapy had an impact on imaging effect, which may reduce the detection rate. After all, methylene blue fluorescence imaging has great potential to be used into breast-conserving surgery for tumor-positive margins detection, but further clinical trial study is needed ( http://www.chictr.org.cn/ Clinical Trial Registry ID: ChiCTR1800015400, Near-infrared fluorescence imaging applied in breast cancer identification with methylene blue).

Indocyanine Green Fluorescence Versus Blue Dye or Radioisotope Regarding Detection Rate of Sentinel Lymph Node Biopsy and Nodes Removed in Breast Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

Either blue dye (BD) or radioisotope (RI) is mainly used for sentinel lymph node biopsy (SLNB) in breast cancer patients. Unlike the BD, RI has lower false-negative rate of SLNB. However, its lymphoscintigraphy, difficulty in preoperative injection, and undetected sentinel lymph nodes in some cases cause surgeons to rely only on BD. Currently, indocyanine green (ICG) fluorescence method (ICG-SLNB) is increasingly used as an alternative to the conventional mapping methods in many centers. This systematic review compared ICG with the conventional method of BD or RI in terms of detection rate of SLNB and the number of sentinel lymph nodes (SLNs) removed in.

METHODS

  We searched all relevant studies published between January 2000 and October 2019. All data on for evaluation of SLN detection rate, number of SLNs removed per patient, and tumor positive rate of SLNB were extracted.

RESULTS

A total of 30 studies, including 4,216 SLN procedures were retrieved. There was a statistically significant difference between ICG and BD method in terms of SLN detection rate (OR, 6.73; 95% CI, 4.20-10.78). However, there was no significant difference between ICG and RI in this regard (OR, 0.90; 95% CI, 0.40-2.03). The number of SLNs removed per patient were 2.35 (1.46-5.4), 1.92 (1.0-3.64), and 1.72 (1.35-2.08) for ICG, BD, and RI, respectively. Only in 8 studies, the tumor positive rates in SLNB could be analyzed (ICG, 8.5-20.7%; BD, 12.7-21.4%; RI, 11.3-16%).

CONCLUSION

ICG-SLNB could be an additional or an alternative method for axillary node mapping in breast cancer.<br />.

Indocyanine green fluorescence method for sentinel lymph node biopsy in breast cancer

BACKGROUND/OBJECTIVE

Breast biopsy and analysis of sentinel lymph nodes (SLNs) accurately predict tumor status in the affected basin and help in avoiding unnecessary axillary lymph node dissection, which is associated with remarkable morbidity risk. Blue dye and radioisotope are the most widely used mapping agents, but non-radioactive tracers of comparable accuracy warrant further investigation. This study aimed to investigate utilization of indocyanine green (ICG) fluorescence in sentinel node localization compared with blue dye and to assess the incremental value of ICG.

METHODS

A total of 39 consecutive patients underwent sentinel lymph node biopsy (SLNB) (40 cases: 38 unilateral and 1 bilateral) with combined blue dye and ICG for localization. The obtained fluorescence images of the lymphatic system were investigated.

RESULTS

All 84 lymph nodes removed in 40 procedures were identified by ICG, but only 37 were identified by blue dye. The ICG method identified an average of 2.1 SLNs in 39 of 40 cases with a detection rate of 97.5%, but only 0.93 SLN per case with blue dye. Subcutaneous lymphatic channel patterns were also detected by fluorescent imaging in 37 procedures, which all revealed lymphatic drainage toward the axilla except in one case with internal mammary pathway.

CONCLUSION

This study demonstrated the accuracy and safety of ICG for SLNB and its superiority to blue dye method in SLN localization. Therefore, ICG fluorescence method is safe and effective addition in breast clinical settings, wherein blue dye alone is used.

Use of indocyanine green fluorescence compared to radioisotope for sentinel lymph node biopsy in early-stage breast cancer: systematic review and meta-analysis

BACKGROUND

In early-stage breast cancer, indocyanine green (ICG)-fluorescence based sentinel lymph node (SLN) detection is being considered. This is a meta-analysis of SLN detection rates and sensitivity of ICG-fluorescence compared to radioisotope (RI), to evaluate its clinical applicability.

DATA SOURCES

Systematic review of full-text articles from PubMed and Scopus, of women with early breast cancer who underwent SLN mapping using ICG and RI concurrently was performed. The meta-analysis was performed using the Mantel-Haenszel method.

RESULTS

2301 patients from 19 studies were included. No significant difference was observed between ICG and RI for SLN detection (OR0.90,95%CI0.66-1.24) or sensitivity (OR1.23,95%CI0.73-2.05) with heterogeneity between studies (I² = 58%,P = 0.003). Sensitivity of dual mapping (ICG + RI) was significantly better compared to single mapping with RI (OR3.69,95%CI1.79-7.62) or ICG (OR3.32,95%CI1.52-7.24) alone with no heterogeneity between studies (I² = 0%,P = 0.004).

CONCLUSION

ICG-fluorescence could complement RI method or provide alternative in centers with poor accessibility to RI lymphoscintigraphy.

Fluorescence Image-Guided Surgery - a Perspective on Contrast Agent Development

In the past several decades, a number of novel fluorescence image-guided surgery (FGS) contrast agents have been under development, with many in clinical translation and undergoing clinical trials. In this review, we have identified and summarized the contrast agents currently undergoing clinical translation. In total, 39 novel FGS contrast agents are being studied in 85 clinical trials. Four FGS contrast agents are currently being studied in phase III clinical trials and are poised to reach FDA approval within the next two to three years. Among all novel FGS contrast agents, a wide variety of probe types, targeting mechanisms, and fluorescence properties exists. Clinically available FGS imaging systems have been developed for FDA approved FGS contrast agents, and thus further clinical development is required to yield FGS imaging systems tuned for the variety of contrast agents in the clinical pipeline. Additionally, study of current FGS contrast agents for additional disease types and development of anatomy specific contrast agents is required to provide surgeons FGS tools for all surgical specialties and associated comorbidities. The work reviewed here represents a significant effort from many groups and further development of this promising technology will have an enormous impact on surgical outcomes across all specialties.

Dye-doped silica nanoparticles: synthesis, surface chemistry and bioapplications

Background

Fluorescent silica nanoparticles have been extensively utilised in a broad range of biological applications and are facilitated by their predictable, well-understood, flexible chemistry and apparent biocompatibility. The ability to couple various siloxane precursors with fluorescent dyes and to be subsequently incorporated into silica nanoparticles has made it possible to engineer these fluorophores-doped nanomaterials to specific optical requirements in biological experimentation. Consequently, this class of nanomaterial has been used in applications across immunodiagnostics, drug delivery and human-trial bioimaging in cancer research.

Main body

This review summarises the state-of-the-art of the use of dye-doped silica nanoparticles in bioapplications and firstly accounts for the common nanoparticle synthesis methods, surface modification approaches and different bioconjugation strategies employed to generate biomolecule-coated nanoparticles. The use of dye-doped silica nanoparticles in immunoassays/biosensing, bioimaging and drug delivery is then provided and possible future directions in the field are highlighted. Other non-cancer-related applications involving silica nanoparticles are also briefly discussed. Importantly, the impact of how the protein corona has changed our understanding of NP interactions with biological systems is described, as well as demonstrations of its capacity to be favourably manipulated.

Conclusions

Dye-doped silica nanoparticles have found success in the immunodiagnostics domain and have also shown promise as bioimaging agents in human clinical trials. Their use in cancer delivery has been restricted to murine models, as has been the case for the vast majority of nanomaterials intended for cancer therapy. This is hampered by the need for more human-like disease models and the lack of standardisation towards assessing nanoparticle toxicity. However, developments in the manipulation of the protein corona have improved the understanding of fundamental bio–nano interactions, and will undoubtedly assist in the translation of silica nanoparticles for disease treatment to the clinic.

Fluorescence Imaging of Breast Tumors and Gastrointestinal Cancer

Optical imaging offers a high potential for noninvasive detection and therapy of cancer in humans. Recent advances in instrumentation for diffuse optical imaging have led to new capabilities for the detection of cancer in highly scattering tissue such as the female breast. In particular, fluorescence imaging was made applicable as a sensitive technique to image molecular probes in vivo. We review recent developments in the detection of breast cancer and fluorescence-guided surgery of the breast by contrast agents available for application on humans. Detection of cancer has been investigated with the unspecific contrast agents "indocyanine green" and "omocianine" so far. Hereby, indocyanine green was found to offer high potential for the differentiation of malignant and benign lesions by exploiting vessel permeability for macromolecules as a cancer-specific feature. Tumor-specific molecular targeting and activatable probes have been investigated in clinical trials for fluorescence-guided tumor margin detection. In this application, high spatial resolution can be achieved, since tumor regions are visualized mainly at the tissue surface. As another example of superficial tumor tissue, imaging of lesions in the gastrointestinal tract is discussed. Promising results have been obtained on high-risk patients with Barrett´s esophagus and with ulcerative colitis by administering 5-aminolevulinic acid which induces accumulation of protoporphyrin IX serving as a tumor-specific fluorescent marker. Time-gated fluorescence imaging and spectroscopy are effective ways to suppress underlying background from tissue autofluorescence. Furthermore, recently developed tumor-specific molecular probes have been demonstrated to be superior to white-light endoscopy offering new ways for early detection of malignancies in the gastrointestinal tract.

Usefulness of blood flow evaluation by indocyanine green fluorescence system in laparoscopic anterior resection

BACKGROUND

One of the major cause of anastomotic leakage (AL) in anterior resection of the rectum is insufficient blood flow of the remnant colon. The indocyanine green fluorescence system (ICG-FS) can visualize the blood flow of organs intra-operatively. The aim of this study is to investigate the usefulness of ICG-FS for evaluating the blood flow of the remnant colon in laparoscopic anterior resection.

MATERIALS AND METHODS

Rectal cancer patients (n=24) who underwent laparoscopic anterior resection were included in this study. After resection of the rectum, 7.5mg of ICG was administered intravenously, and the blood flow of the oral stump was evaluated by the ICG-FS. The relationship between the fluorescence time (FT) of the oral stump and AL was investigated retrospectively.

RESULT

Two of twenty-four patients (8.3%) suffered AL. The FT of these two cases were over 60 seconds. In the case with the FT was over 80 seconds, we performed additional resection of the late fluorescence portion of the remnant colon and could avoid AL. In patients whose FT was under 60 seconds, no patients suffered AL.

CONCLUSION

ICG-FS may be useful for evaluating the blood flow of the remnant colon to avoid AL in laparoscopic anterior resection. J. Med. Invest. 66 : 65-69, February, 2019.

Preliminary study of real-time three-dimensional contrast-enhanced ultrasound of sentinel lymph nodes in breast cancer

PURPOSE

To investigate the clinical value of real-time three-dimensional contrast-enhanced ultrasound (3D-CEUS) in the detection of sentinel lymph nodes (SLNs) and drainage lymphatics in breast cancer patients.

METHOD

The prospective study was performed in women with pathology-confirmed T1/2 breast cancer between June 2016 and December 2017 who underwent sentinel lymph node biopsy and 3D-CEUS. The number, size, location, enhancement pattern of SLNs, and the lymphatic drainage patterns were reviewed. The routes, location of SLNs, and lymph channels (LCs) on the surface were marked. All patients underwent blue dye-guided sentinel lymph node biopsy (SLNB) finally.

RESULTS

According to the postoperative pathology findings and the blue dye staining of the lymphatic drainage routes, there are six patterns of lymphatic drainage routes and the coincidence rate of the 3D-CEUS was 97.4%; the sensitivity, specificity, positive predictive value, negative predictive value, the LN detection rate, and the correct diagnosis rate of the 3D-CEUS were 75%, 93.0%, 81.8%, 89.9%, 95.3%, and 87.7%, respectively.

CONCLUSION

3D-CEUS is a new feasible and useful approach to detect the SLNs and LCs. 3D-CEUS can accurately localize the LCs and SLNs and estimate the presence of metastatic lymph nodes.

KEY POINTS

• The three-dimensional contrast-enhanced ultrasound can detect the sentinel lymph nodes. • The three-dimensional contrast-enhanced ultrasound can show the stereo direction of sentinel lymph nodes and lymph drainage routes. • The three-dimensional contrast-enhanced ultrasound can accurately localize the LCs and SLNs and estimate the presence of metastatic lymph nodes.

Lower-Limb Lymphatic Drainage Pathways and Lymph Nodes: A CT Lymphangiography Cadaver Study

Background Most lymphatic imaging examinations of the lower limb require intradermal or subcutaneous injection of tracer material into the foot to demonstrate the lymphatic vessels; however, no standard protocol exists, and single or multiple injections are applied at different sites. Purpose To determine the three-dimensional relationships between each lymphatic group of the lower limb and corresponding regional lymph nodes. Materials and Methods A total of 130 lower limbs (55 from men and 75 from women) from 83 fresh human cadavers were studied. Lymphatic vessels were first visualized by using indocyanine green fluorescent lymphography with 19 injection sites in the foot, classified into four distinct lymphatic groups (anteromedial, anterolateral, posteromedial, and posterolateral); dilute oil-based contrast material was then injected. Next, specimens were scanned with CT and three-dimensional images were analyzed. Results The anteromedial and anterolateral lymphatic groups of the lower-leg lymphatic vessels were independent of each other and connected to different regional lymph nodes in the inguinal region. The posteromedial group and the anteromedial group in the lower leg drained to the same inguinal lymph nodes. Only the posterolateral group of lymphatic vessels in the lower leg drained to the popliteal lymph nodes. Leg lymphatic drainage pathways were independent of genital pathways. Conclusion Standard injection sites at the web spaces between the toes did not help visualize some lymph nodes of the lower leg. Additional injection sites in the medial, lateral, and posterior aspect of the foot would be better for evaluating the whole lymphatic pathways and regional lymph nodes and for improving understanding of leg lymphedema. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Weiss and Liddel in this issue.

Applications of near infrared and surface enhanced Raman scattering techniques in tumor imaging: A short review

Imaging technologies play a vital role in clinical oncology and have undergone massive growth over the past few decades. Research in the field of tumor imaging and biomedical diagnostics requires early detection of physiological alterations so as to provide curative treatment in real time. The objective of this review is to provide an insight about near infrared fluorescence (NIRF) and surface enhanced Raman scattering (SERS) imaging techniques that can be used to expand their capabilities for the early detection and diagnosis of cancer cells. Basic setup, principle and working of the instruments has been provided and common NIRF imaging agents as well as SERS tags are also discussed besides the analytical advantages/disadvantages of these techniques. This review can help researchers working in the field of molecular imaging to design cost effective fluorophores and SERS tags to overcome the limitations of both NIRF as well as SERS imaging technologies.

Novel method of intraoperative liver tumour localisation with indocyanine green and near-infrared imaging

INTRODUCTION

Fluorescence imaging (FI) with indocyanine green (ICG) is increasingly implemented as an intraoperative navigation tool in hepatobiliary surgery to identify hepatic tumours. This is useful in minimally invasive hepatectomy, where gross inspection and palpation are limited. This study aimed to evaluate the feasibility, safety and optimal timing of using ICG for tumour localisation in patients undergoing hepatic resection.

METHODS

From 2015 to 2018, a prospective multicentre study was conducted to evaluate feasibility and safety of ICG in tumour localisation following preoperative administration of ICG either on Day 0-3 or Day 4-7.

RESULTS

Among 32 patients, a total of 46 lesions were resected: 23 were hepatocellular carcinomas (HCCs), 12 were colorectal liver metastases (CRLM) and 11 were benign lesions. ICG FI identified 38 (82.6%) lesions prior to resection. The majority of HCCs were homogeneous fluorescing lesions (56.6%), while CLRM were homogeneous (41.7%) or rim-enhancing (33.3%). The majority (75.0%) of the lesions not detected by ICG FI were in cirrhotic livers. Most (84.1%) of ICG-positive lesions detected were < 1 cm deep, and half of the lesions ≥ 1 cm in depth were not detected. In cirrhotic patients with malignant lesions, those given ICG on preoperative Day 0-3 and Day 4-7 had detection rates of 66.7% and 91.7%, respectively. There were no adverse events.

CONCLUSION

ICG FI is a safe and feasible method to assist tumour localisation in liver surgery. Different tumours appear to display characteristic fluorescent patterns. There may be no disadvantage of administering ICG closer to the operative date if it is more convenient, except in patients with liver cirrhosis.

A new indocyanine green fluorescence lymphography protocol for identification of the lymphatic drainage pathway for patients with breast cancer-related lymphoedema

Background

Breast cancer related lymphoedema (BCRL) is a common side effect of cancer treatment. Recently indocyanine green (ICG) fluorescent lymphography has become a popular method for imaging the lymphatics, however there are no standard protocols nor imaging criteria. We have developed a prospective protocol to aid in the diagnosis and therapeutic management of BCRL.

Methods

Lymphatic imaging procedures were conducted in three phases. Following initial observation of spontaneous movement of ICG in phase one, manual lymphatic drainage (MLD) massage was applied to facilitate ICG transit via the lymphatics in phase two. All imaging data was collected in phase three. Continuous lymphatic imaging of the upper limb was conducted for approximately an hour and lymphatic drainage pathways were determined. Correlations between the drainage pathway and MD Anderson Cancer Centre (MDACC) ICG lymphoedema stage were investigated.

Results

One hundred and three upper limbs with BCRL were assessed with this new protocol. Despite most of the patients having undergone axillary node dissection, the ipsilateral axilla drainage pathway was the most common (67% of upper limbs). We found drainage to the ipsilateral axilla decreased as MDACC stage increased. Our results suggest that the axillary pathway remained patent for over two-thirds of patients, rather than completely obstructed as conventionally thought to be the case for BCRL.

Conclusions

We developed a new ICG lymphography protocol for diagnosing BCRL focusing on identification of an individual patient’s lymphatic drainage pathway after lymph node surgery. The new ICG lymphography protocol will allow a personalised approach to manual lymphatic drainage massage and potentially surgery.

Fluorescence-Guided Surgery for Hepatoblastoma with Indocyanine Green

Fluorescence-guided surgery with indocyanine green (ICG) for malignant hepatic tumors has been gaining more attention with technical advancements. Since hepatoblastomas (HBs) possess similar features to hepatocellular carcinoma, fluorescence-guided surgery can be used for HBs, as aggressive surgical resection, even for distant metastases of HBs, often contributes positively to R0 (complete) resection and subsequent patient survival. Despite a few caveats, fluorescence-guided surgery allows for the more sensitive identification of lesions that may go undetected by conventional imaging or be invisible macroscopically. This leads to precise resection of distant metastatic tumors as well as primary liver tumors.

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

INTRODUCTION

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

METHODS AND ANALYSIS

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

ETHICS AND DISSEMINATION

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

TRIAL REGISTRATION NUMBER

UMIN000031054 and jRCT1051180070.

Do we need to shift from dye injection to fluorescence in respective liver surgery?

Anatomical hepatectomy for hepatocellular carcinoma (HCC) has been a standard procedure for hepatic surgeons by guaranteeing curability and hepatic parenchymal preservation. Recently, indocyanine green (ICG) fluorescent imaging has been applied for hepatobiliary surgery, in substitution for cholangiography, to detect hepatic tumors, and the anatomical hepatectomy. This technique can reveal the hepatic segmental border line on the hepatic surface and its boundary plane during hepatic parenchymal resection. Initially, dye staining with indigo-carmine has been used for anatomical hepatectomy, and recently, ICG fluorescent imaging is applied to this technique. The conventional dye staining method is an innovative method for indicate the hepatic segmental border on the hepatic surface that can otherwise never be visualized. However, the intensity of staining is inconsistent or skill-dependent and disappears quickly with dilution because it is not taken up by the liver. The advantages of ICG fluorescent segmental staining are its high reproducibility and sensitivity. It stays in the injected segment for a few hours because ICG is taken up by hepatocytes. The segmental border inside the liver can also be visualized by this technique, thus providing intraoperative navigation. The limitation of ICG fluorescent staining may be whole liver staining because of recirculation of over dose of ICG, which is difficult to cancel the fluorescence once ICG is injected. With further improvement of the imaging system and standardization of the ICG usage (dose and timing), ICG fluorescent imaging might replace the conventional dye staining method in its role in anatomical hepatectomy.

Residual cancerous lesion and vein tumour thrombus identified intraoperatively using a fluorescence navigation system in liver surgery

AIM

The main aims of this study are to investigate the clinical application value of using indocyanine green fluorescence imaging for ensuring complete resection of tumour tissue during hepatectomy and to evaluate the diagnostic efficacy of near-infrared (NIR) fluorescence imaging system using indocyanine green in hepatectomy.

METHODS

After undergoing liver resection at the Affiliated Hospital of Southwest Medical University from July 2017 to May 2018, 35 eligible patients were included in this study. The liver surface and resection margin were intraoperatively assessed by intraoperative ultrasonography and NIR fluorescence imaging, after intravenous administration of indocyanine green (0.5 mg/kg) 72-96 h prior to surgery. The intraoperative observations were compared with the pathological findings in the liver.

RESULTS

In the 35 patients, a total of 53 lesions were found, of which 42 were malignant lesions. The analysis results showed that the sensitivity and accuracy of detection using NIR fluorescence imaging were significantly higher than with intraoperative ultrasonography (P < 0.05). However, there was no difference between contrast-enhanced helical computed tomography and NIR fluorescence imaging in finding lesions (P > 0.05). In addition, 11 new suspicious lesions were detected only by NIR fluorescence imaging in the liver surface and resection margin during surgery, four of which were hepatocellular carcinoma. We also detected four vein tumour thrombi using the NIR fluorescence navigation system.

CONCLUSIONS

The NIR fluorescence navigation system enables the identification of small tumours, residual cancer tissues in resection margin and venous tumour embolies in real time and enhances the accuracy and integrity of liver resection.

The Sentinel Lymph Node Biopsy Using Indocyanine Green Fluorescence Plus Radioisotope Method Compared With the Radioisotope-Only Method for Breast Cancer Patients After Neoadjuvant Chemotherapy: A Prospective, Randomized, Open-Label, Single-Center Phase 2 Trial

BACKGROUND

This study aimed to compare the sentinel lymph node (SLN) identification rates for breast cancer patients after neoadjuvant chemotherapy (NAC) between the dual method (DM) of indocyanine green fluorescence (ICG-F) plus a radioisotope (RI) and RI alone.

METHODS

This randomized study enrolled 130 patients who received NAC for breast cancer and 122 patients who received SLN biopsy (SLNB) using either DM (n = 58) or RI only (n = 64). The study compared the identification rate, number of SLNs, and detection time of SLNB.

RESULTS

Among the 122 patients, 113 (92.6%) were clinically node-positive before NAC. The SLN identification rate was 98.3% in the DM group and 93.8% in the RI group (p = 0.14). The DM group and the RI group were similar in the average number of SLNs (2.2 ± 1.13 vs. 1.9 ± 1.33; p = 0.26) and the time to detection of the first SLN (8.7 ± 4.98 vs. 8.3 ± 4.31 min; p = 0.30). In the DM group, transcutaneous lymphatic drainage was visualized by fluorescence imaging for 65.5% (38 of 58) of the patients. The SLN identification rate was 94.7% using ICG-F and 93% using RI (p = 0.79). During and after the operation, no complications, including allergic reactions or skin necrosis, occurred.

CONCLUSIONS

This study is the first randomized trial to use ICG-F for SLNB in breast cancer patients after NAC. The DM including ICG-F could be a feasible and safe method for SLNB in initially node-positive breast cancer patients with NAC.

Navigation surgery using indocyanine green fluorescent imaging for hepatoblastoma patients

BACKGROUND

Technology for detecting liver tumors and identifying the bile ducts using indocyanine green (ICG) has recently been developed. However, the usefulness and limitations of ICG navigation surgery for hepatoblastoma (HB) have not been fully clarified. We herein report our experiences with surgical navigation using ICG for in HB patients.

METHODS

In 5 HB patients, 10 ICG navigation surgeries were performed using a 10-mm infrared fluorescence imaging scope after the injection of 0.5 mg/kg ICG intravenously. The surgical and clinical features were collected retrospectively.

RESULTS

Navigation surgery using ICG was performed for primary liver tumors in 4 cases, and the timing of ICG injection was 90.5 ± 33.7 h before the operation. All tumors exhibited intense fluorescence from the liver surface. ICG navigation for the primary liver tumor was useful for detecting the residual tumor at the stump and invasion to the diaphragm during surgery. Six lung surgeries using ICG navigation were performed. The timing of ICG injection was 21.8 ± 3.4 h before the operation. The size of the metastatic tumor was 7.4 ± 4.1 mm (1.2-15 mm). Of 11 metastatic tumors detected by computed tomography (CT), 10-including the smallest tumor (1.2 mm)-were able to be detected by ICG from the lung surface. The depth of the 10 ICG-positive tumors from the lung surface was 0.9 ± 1.9 mm (0-6 mm), and the depth of the single ICG-negative tumor was 12 mm. One lesion not detected by CT showed ICG false positivity.

CONCLUSION

Navigation surgery using ICG for patients with HB was useful for identifying tumors and confirming complete resection. However, in ICG navigation surgery, we must be aware of the limitations with regard to the tumor size and the depth from the surface.

Detection of Sentinel Lymph Nodes with Near-Infrared Imaging in Malignancies

Optical molecular imaging, a highly sensitive and noninvasive technique which is simple to operate, inexpensive, and has the real-time capability, is increasingly being used in the diagnosis and treatment of carcinomas. The near-infrared fluorescence dye indocyanine green (ICG) is widely used in optical imaging for the dynamic detection of sentinel lymph nodes (SLNs) in real time improving the detection rate and accuracy. ICG has the advantages of low scattering in tissue absorbance, low auto-fluorescence, and high signal-to-background ratio. The detection rate of axillary sentinel lymph nodes biopsy (SLNB) in breast cancers with ICG was more than 95 %, the false-negative rate was lower than 10 %, and the average detected number ranged from 1.75 to 3.8. The combined use of ICG with nuclein or blue dye resulted in a lower false-negative rate. ICG is also being used for the sentinel node detection in other malignant cancers such as head and neck, gastrointestinal, and gynecological carcinomas. In this article, we provide an overview of numerous studies that used the near-infrared fluorescence imaging to detect the sentinel lymph nodes in breast carcinoma and other malignant cancers. It is expected that with improvements in the optical imaging systems together with the use of a combination of multiple dyes and verification in large clinical trials, optical molecular imaging will become an essential tool for SLN detection and image-guided precise resection.

Contrast improvement in indocyanine green fluorescence sensing in thick tissue using a time-gating method

Indocyanine green-based fluorescence imaging techniques are very powerful in clinical applications, but the imaging is restricted to the signal from the near-surface region of tissue. Here, we focus on the method to discriminate the fluorescence signal from the background using a time-domain gating technique. The contrast of the fluorescence image from a fluorescence object at more than 1 cm depth in a meat phantom could be enhanced about 4-5 times relative to the continuous wave method if the time-gate range was properly selected. Further, a Monte Carlo simulation with a simple background model indicates that a shorter source and detector distance is more effective to improve the contrast. The simple time-gating method will enable a highly sensitive fluorescence detection in thick tissue.

Applications of SNAP-tag technology in skin cancer therapy

BACKGROUND

Cancer treatment in the 21st century has seen immense advances in optical imaging and immunotherapy. Significant progress has been made in the bioengineering and production of immunoconjugates to achieve the goal of specifically targeting tumors.

DISCUSSION

In the 21st century, antibody drug conjugates (ADCs) have been the focus of immunotherapeutic strategies in cancer. ADCs combine the unique targeting of monoclonal antibodies (mAbs) with the cancer killing ability of cytotoxic drugs. However, due to random conjugation methods of drug to antibody, ADCs are associated with poor antigen specificity and low cytotoxicity, resulting in a drug to antibody ratio (DAR) >1. This means that the cytotoxic drugs in ADCs are conjugated randomly to antibodies, by cysteine or lysine residues. This generates heterogeneous ADC populations with 0 to 8 drugs per an antibody, each with distinct pharmacokinetic, efficacy, and toxicity properties. Additionally, heterogeneity is created not only by different antibody to ligand ratios but also by different sites of conjugation. Hence, much effort has been made to find and establish antibody conjugation strategies that enable us to better control stoichiometry and site-specificity. This includes utilizing protein self-labeling tags as fusion partners to the original protein. Site-specific conjugation is a significant characteristic of these engineered proteins. SNAP-tag is one such engineered self-labeling protein tag shown to have promising potential in cancer treatment. The SNAP-tag is fused to an antibody of choice and covalently reacts specifically in a 1:1 ratio with benzylguanine (BG) substrates, eg, fluorophores or photosensitizers, to target skin cancer. This makes SNAP-tag a versatile technique in optical imaging and photoimmunotherapy of skin cancer.

CONCLUSION

SNAP-tag technology has the potential to contribute greatly to a broad range of molecular oncological applications because it combines efficacious tumor targeting, minimized local and systemic toxicity, and noninvasive assessment of diagnostic/prognostic molecular biomarkers of cancer.

Identification of extrahepatic metastasis of hepatocellular carcinoma using indocyanine green fluorescence imaging

BACKGROUND/PURPOSE

Intraoperative fluorescence imaging with indocyanine green (ICG) plays a significant role in the identification of hepatocellular carcinoma (HCC) during Hepatectomy. Despite that, few researchers have reported using ICG fluorescence imaging to detect extrahepatic metastases. Herein, we report the successful application of ICG fluorescence imaging in the detection of extrahepatic metastatic lesions from primary liver cancer.

METHODS

In two HCC patients, a near-infrared fluorescence imaging system was used to intraoperatively examine the abdominal cavity for implantation metastasis after hepatectomy of the primary tumor, following pre-operative intravenous infusion with ICG.

RESULTS

In the first case, the abdominal cavity implantation metastasis exhibited intense fluorescence and clear boundaries of tumors during abdominal tumor resection, and there was no fluorescence in the resection margin. In the second case, a new lesion that was not detected by preoperative imaging examination was found in the omentum by ICG fluorescence imaging. Intraoperative rapid freezing pathology showed that it was an adenocarcinoma. Accordingly, we revised the tumor staging.

CONCLUSION

ICG fluorescence imaging can not only detect intrahepatic metastases, but also extrahepatic metastases. Furthermore, it can help surgeons correct tumor staging during surgery.

Paired-Agent Fluorescence Molecular Imaging of Sentinel Lymph Nodes Using Indocyanine Green as a Control Agent for Antibody-Based Targeted Agents

Purpose

Paired-agent molecular imaging methods, which employ coadministration of an untargeted, "control" imaging agent with a targeted agent to correct for nonspecific uptake, have been demonstrated to detect 200 cancer cells in a mouse model of metastatic breast cancer. This study demonstrates that indocyanine green (ICG), which is approved for human use, is an ideal control agent for future paired-agent studies to facilitate eventual clinical translation.

Methods

The kinetics of ICG were compared with a known ideal control imaging agent, IRDye-700DX-labeled antibody in both healthy and metastatic rat popliteal lymph nodes after coadministration, intradermally in the footpad.

Results

The kinetics of ICG and antibody-based imaging agent in tumor-free rat lymph nodes demonstrated a strong correlation with each other (r = 0.98, p < 0.001) with a measured binding potential of -0.102 ± 0.03 at 20 min postagent injection, while the kinetics of ICG and targeted imaging agent shows significant separation in the metastatic lymph nodes.

Conclusion

This study indicated a potential for microscopic sensitivity to cancer spread in sentinel lymph nodes using ICG as a control agent for antibody-based molecular imaging assays.

High resolution tracking of macrophage cells in deep organs and lymphatics using fluorescent polymer dots

Fluorescent polymer dots for tracking macrophage cells in deep organs using probe-based confocal laser endomicroscopy (pCLE).

Fluorescence guided surgery in liver tumors: applications and advantages

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

A Novel Indocyanine Green Fluorescence-Guided Video-Assisted Technique for Sentinel Node Biopsy in Breast Cancer

BACKGROUND

The equipment to detect indocyanine green (ICG) fluorescence for sentinel lymph node (SLN) biopsy in breast cancer is not widely accessible nor optimal. The fluorescence appears as a poorly defined white shine on a black background, and dimmed lighting is required. The aim of this study was to assess the feasibility, accuracy and healthcare costs of a novel approach for SLN biopsy by a video-assisted ICG-guided technique.

METHODS

The technique for detecting SLN was radioisotope (RI) in 194 cases, video-assisted ICG-guided in 70 cases and a combined method in 71 cases. In the video-assisted ICG group, a full HD laparoscopic system equipped with xenon lamps was used for a laser-free detection of ICG within a colored and magnified high-resolution image.

RESULTS

Detection of ICG fluorescence using a laparoscope with a near-infrared filter provided a highly defined and colored image during SLN biopsy. SLN was identified in 100% of patients in all groups. Multiple SLNs were identified in 0.5% of RI patients, in 12.9% of ICG patients and in 14.1% of ICG + RI patients (p < 0.0001). In ICG + RI group, 95.1% of lymph nodes were radioactive and 92.7% were fluorescent. Operative times and healthcare costs were equivalent between groups.

CONCLUSIONS

Video-assisted ICG-guided technique is a feasible and surgeon-friendly method for SLN biopsy, with equivalent efficacy compared to RI, providing an accurate staging of the axilla.

Indocyanine green for the prevention of anastomotic leaks following esophagectomy: a meta-analysis

BACKGROUND

Intraoperative evaluation with fluorescence angiography using indocyanine green (ICG) offers a dynamic assessment of gastric conduit perfusion and can guide anastomotic site selection during an esophagectomy. This study aims to evaluate the predictive value of ICG for the prevention of anastomotic leak following esophagectomy.

METHODS

A comprehensive search of electronic databases using the search terms "indocyanine/fluorescence" AND esophagectomy was completed to include all English articles published between January 1946 and 2018. Articles were selected by two independent reviewers. The quality of included studies was assessed using the Methodological Index for Non-Randomized Studies (MINORS) instrument.

RESULTS

Seventeen studies were included for meta-analysis after screening and exclusions. The pooled anastomotic leak rate when ICG was used was found to be 10%. When limited to studies without intraoperative modifications, the pooled sensitivity, specificity, and diagnostic odds ratio were 0.78 (95% CI 0.52-0.94; p = 0.089), 0.74 (95% CI 0.61-0.84; p = 0.012), and 8.94 (95% CI 1.24-64.21; p = 0.184), respectively. Six trials compared ICG with an intraoperative intervention to improve perfusion to no ICG. ICG with intervention was found to have a risk reduction of 69% (OR 0.31, 95% CI 0.15-0.63).

CONCLUSIONS

In non-randomized trials, the use of ICG as an intraoperative tool for visualizing microvascular perfusion and conduit site selection to decrease anastomotic leaks is promising. However, poor data quality and heterogeneity in reported variables limits generalizability of findings. Randomized, multi-center trials are needed to account for independent risk factors for leak rates and to better elucidate the impact of ICG in predicting and preventing anastomotic leaks.

Patterns of lymphatic drainage after axillary node dissection impact arm lymphoedema severity: A review of animal and clinical imaging studies

Upper extremity lymphoedema after axillary node dissection is an iatrogenic disease particularly associated with treatment for breast or skin cancer. Anatomical studies and lymphangiography in healthy subjects identified that axillary node dissection removes a segment of the lymphatic drainage pathway running from the upper limb to the sub-clavicular vein, creating a surgical break. It is reasonable to infer that different patterns of lymphatic drainage may occur in the upper limb following surgery and contribute to the various presentations of lymphoedema from none to severe. Firstly, we reviewed animal imaging studies that investigated the repair of lymphatic drainage pathways from the limb after lymph node dissection. Secondly, we examined clinical imaging studies of lymphatic drainage pathways after axillary node dissection, including lymphangiography, lymphoscintigraphy and indocyanine green fluorescence lymphography. Finally, based on the gathered data, we devised a set of general principles for the restoration of lymphatic pathways after surgery. Lymphoscintigraphy shows that restoration of the original lymphatic pathway to the axilla after its initial disruption by nodal dissection was not uncommon and may prevent lymphoedema. We found that regenerated lymphatic vessels and dermal backflow (the reflux of lymph to the skin) contributed to either restoration of the original pathway or rerouting of the lymphatic pathway to other regional nodes. Variation in the lymphatic drainage pathway and the mechanisms of fluid drainage itself are the foundation of new lymphatic drainage patterns considered to be significant in determining the severity with which lymphoedema develops.