Real-time near-infrared fluorescence guided surgery in gynecologic oncology: a review of the current state of the art

Ultrafast Intelligent Sensor for Integrated Biological Fluorescence Imaging and Recognition

Fluorescence imaging and recognition are core technologies in targeted medicine, pathological surgery, and biomedicine. However, current imaging and recognition systems are separate, requiring repeated data transfers for imaging and recognition that lead to delays and inefficiency, hindering the capture of rapidly changing physiological processes and biological phenomena. To address these problems, we propose an integrated intelligent sensor for biological fluorescence imaging and ultrafast recognition. This sensor integrates an imaging system based on a photodetector array and a recognition system based on neural networks on a single chip, featuring a highly compact structure, a continuously adjustable optical response, and reconfigurable electrical performance. The unified architecture of the imaging and recognition systems enables ultrafast recognition (19.63 μs) of tumor margins. Additionally, the special organic materials and bulk heterojunction structure endow the photodetector array with strong wavelength dependence, achieving high specific detectivity (3.06 × 1012 Jones) in the narrowband near-infrared range commonly used in biomedical imaging (600-800 nm). After training, the sensor can accurately recognize biological fluorescence edges in real time, even under interference from other colored light noise. Benefiting from its rapidity and high accuracy, we demonstrated a simulated surgical experiment showcasing tumor edge fluorescence imaging, recognition, and cutting. This integrated approach holds the potential to establish a novel paradigm for designing and manufacturing intelligent medical sensors.

Polymeric Nanostructures Revolutionizing Cervical Cancer: Diagnostics, Therapeutics, and Theranostics

Cervical cancer is the fourth most common cancer among women. Despite recent advancements in diagnostics and therapeutics, this disease is still a formidable challenge to deal with. Conventional methods for detecting human papillomavirus infection and imaging the tissues face major hurdles due to a lack of signal specificity and obscured resolution respectively. Moreover, chemotherapeutics struggle against the development of multidrug resistance and rapid clearance. With their easily tunable properties, polymeric nanostructures present a promising avenue for rapid, specific, and efficient diagnostics and therapeutics. These nanostructures also serve as theranostic agents that integrate imaging modalities with therapeutic approaches concurrently. This review highlights various types of polymeric nanostructures that serve as biosensors for the detection and quantification of cervical cancer biomarkers and act as nanocarriers for transporting fluorophores, photosensitizers, drugs, and radiosensitizers to their target site of action.

Graphical Abstract

Indocyanine green in gynecologic surgery: Where do we stand? A literature review and meta-analysis

The main objective of this study was to review and perform a meta-analysis of current literature on the use of indocyanine green for sentinel lymph node detection in pelvic gynecologic cancer. We included all studies focusing on indications and procedures associated with the use of ICG in gynecologic surgery and available on the Medline and Pubmed database. For the meta-analysis, random effect models were used for estimation of the 95 % detection rate and 95 % confidence interval, and stratified analyses by cancer type, concentration and localization of injection were performed. A total of 147 articles were included, of which 91 were studied in a meta-analysis. Results concerning detection rate by indocyanine green injection site were found to be 95.1 % and 97.3 % respectively for intracervical injection in 2 or 4 quadrants, and 77.0 % and 94.8 % for hysteroscopic and intradermal injection respectively. Results concerning detection rate by cancer type were 95.8 %, 95.2 %, 94.7 % and 95.7 % respectively for cervical, endometrial, vulvar and endometrial/cervical cancers. Finally, the results concerning detection rate by indocyanine green concentration were 91.2 %, 95.7 %, 96.7 % and 97.7 % for concentrations of <1.25 mg/ml, 1.25 mg/ml, 2.5 mg/ml and 5 mg/ml respectively. In conclusion, indocyanine green is shown to allow highlighting of sentinel lymph nodes with good reliability with an overall indocyanine green detection rate of 95.5 %. Our literature review revealed that indocyanine green feasibility has also been demonstrated in several surgical contexts, notably for reconstructive surgery and detection of endometriosis.

A Green Lantern for the Surgeon: A Review on the Use of Indocyanine Green (ICG) in Minimally Invasive Surgery

Indocyanine green (ICG) fluorescence imaging has revolutionized surgical practice across various medical and surgical specialties. This article reviews the clinical applications of ICG in abdominal, urological, thoracic, and gynecological surgery. ICG fluorescence imaging has been widely adopted in general surgery for various applications, including perfusion assessment, intraoperative visualization of the ureter, and tumor localization. It is particularly valuable in evaluating anastomotic leaks and aiding in precise tumor resection during minimally invasive surgeries. Studies have shown mixed results on its effectiveness in reducing anastomotic leak rates, highlighting the need for further research. In thoracic surgery, ICG facilitates the identification and resection of pulmonary bullae, as well as the precise localization of pulmonary nodules during video-assisted surgery. In urology, ICG aids in localizing renal tumors and guiding selective arterial occlusion during partial nephrectomy. Its role in identifying the lymphatic pathway in prostate cancer and sentinel lymph node biopsy in gynecological cancer is also discussed. Despite its benefits, the use of ICG fluorescence faces challenges such as limited tissue penetration, the potential for false results, a lack of standardized protocols, and high equipment costs. Nonetheless, it remains a powerful tool that could improve surgical outcomes.

Sentinel lymph node procedure in early-stage vulvar cancer: Correlation of lymphoscintigraphy with surgical outcome and groin recurrence

INTRODUCTION

In early-stage vulvar squamous cell carcinoma (VSCC) a sentinel lymph node (SLN) procedure is regarded successful if at least one SLN is removed with minimal residual radioactivity. An inguinofemoral lymphadenectomy is considered if not all SLNs visualized on lymphoscintigraphy can be found, with subsequent increased morbidity. We correlated lymphoscintigraphy findings with surgical outcome and groin recurrence with focus on number of SLNs found.

METHODS

This study concerns a retrospective cohort of 171 women treated for early-stage VSCC who underwent a SLN procedure between 2000 and 2020. The risk of groin recurrence was compared after either a successful or complete SLN procedure, i.e. removal of all SLNs that were visualized on lymphoscintigraphy.

RESULTS

In 13 (7.6%) groins of 171 patients SLN visualization on lymphoscintigraphy failed. In 230 of the 246 (93.5%) groins in which a SLN was visualized, at least one SLN was found during surgery. In 224 of the 246 (91.1%) groins the SLN procedure was regarded either successful (n = 14) or complete (n = 210). An isolated groin recurrence was documented in 5 out of 192 (2.6%, 95%-CI; 0.34 to 4.9) SLN-negative groins after a median follow-up of 47.0 months. All recurrences were noted in the complete SLN group (5/180 groins). The difference with the successful SLN group (0/12 groins) was not significant.

CONCLUSION

Risk of groin recurrence was 2.6% after SLN negative biopsy in early-stage VSCC. The risk appeared not increased if at least one SLN was found with minimal residual radioactivity, in case more SLNs were visualized on lymphoscintigraphy.

Advances in optical molecular imaging for neural visualization

Iatrogenic nerve injury is a significant complication in surgery, which can negatively impact patients' quality of life. Currently, the main clinical neuroimaging methods, such as computed tomography, magnetic resonance imaging, and high-resolution ultrasonography, do not offer precise real-time positioning images for doctors during surgery. The clinical application of optical molecular imaging technology has led to the emergence of new concepts such as optical molecular imaging surgery, targeted surgery, and molecular-guided surgery. These advancements have made it possible to directly visualize surgical target areas, thereby providing a novel method for real-time identification of nerves during surgery planning. Unlike traditional white light imaging, optical molecular imaging technology enables precise positioning and identifies the cation of intraoperative nerves through the presentation of color images. Although a large number of experiments and data support its development, there are few reports on its actual clinical application. This paper summarizes the research results of optical molecular imaging technology and its ability to realize neural visualization. Additionally, it discusses the challenges neural visualization recognition faces and future development opportunities.

Quantifying the Impact of Signal-to-background Ratios on Surgical Discrimination of Fluorescent Lesions

PURPOSE

Surgical fluorescence guidance has gained popularity in various settings, e.g., minimally invasive robot-assisted laparoscopic surgery. In pursuit of novel receptor-targeted tracers, the field of fluorescence-guided surgery is currently moving toward increasingly lower signal intensities. This highlights the importance of understanding the impact of low fluorescence intensities on clinical decision making. This study uses kinematics to investigate the impact of signal-to-background ratios (SBR) on surgical performance.

METHODS

Using a custom grid exercise containing hidden fluorescent targets, a da Vinci Xi robot with Firefly fluorescence endoscope and ProGrasp and Maryland forceps instruments, we studied how the participants' (N = 16) actions were influenced by the fluorescent SBR. To monitor the surgeon's actions, the surgical instrument tip was tracked using a custom video-based tracking framework. The digitized instrument tracks were then subjected to multi-parametric kinematic analysis, allowing for the isolation of various metrics (e.g., velocity, jerkiness, tortuosity). These were incorporated in scores for dexterity (Dx), decision making (DM), overall performance (PS) and proficiency. All were related to the SBR values.

RESULTS

Multi-parametric analysis showed that task completion time, time spent in fluorescence-imaging mode and total pathlength are metrics that are directly related to the SBR. Below SBR 1.5, these values substantially increased, and handling errors became more frequent. The difference in Dx and DM between the targets that gave SBR < 1.50 and SBR > 1.50, indicates that the latter group generally yields a 2.5-fold higher Dx value and a threefold higher DM value. As these values provide the basis for the PS score, proficiency could only be achieved at SBR > 1.55.

CONCLUSION

By tracking the surgical instruments we were able to, for the first time, quantitatively and objectively assess how the instrument positioning is impacted by fluorescent SBR. Our findings suggest that in ideal situations a minimum SBR of 1.5 is required to discriminate fluorescent lesions, a substantially lower value than the SBR 2 often reported in literature.

Fluorescent Indocyanine Green versus Technetium-99m and Blue Dye for Bilateral SENTinel Lymph Node Detection in Stage I-IIA Cervical Cancer (FluoreSENT): protocol for a non-inferiority study

INTRODUCTION

Nowadays, two predominant methods for detecting sentinel lymph nodes (SLNs) in cervical cancer are in use. The most conventional method is a combination of a radiotracer, technetium-99m (^99mTc) and blue dye. More recently, another method for SLN mapping using indocyanine green (ICG) is becoming widely accepted. ICG is a fluorescent dye, visualised intraoperatively with near-infrared (NIR) fluorescence imaging, providing real-time visual navigation. The presumed advantages of ICG over ^99mTc, that is, being cheaper, non-radioactive and logistically more attractive, are only valuable if its detection rate proves to be at least non-inferior. Before omitting the well-functioning and evidence-based combined approach of ^99mTc and blue dye, we aim to provide prospective evidence on the non-inferiority of ICG with NIR fluorescence imaging.

METHODS AND ANALYSIS

We initiated a prospective non-inferiority study with a paired comparison of both SLN methods in a single sample of 101 patients with International Federation of Gynecology and Obstetrics (FIGO) stage IA-IB2 or IIA1 cervical cancer receiving primary surgical treatment. All patients undergo SLN mapping with ICG and NIR fluorescence imaging in adjunct to mapping with ^99mTc (including single photon emission computed tomography with X-ray computed tomography (SPECT/CT)) and blue dye. Surgeons start SLN detection with ICG while being blinded for the preoperative outcome of SPECT/CT to avoid biased detection with ICG. Primary endpoint of this study is bilateral SLN detection rate of both methods (ie, detection of at least one SLN in each hemipelvis). Since we compare strategies for SLN mapping that are already applied in current daily practice for different types of cancer, no additional risks or burdens are expected from these study procedures.

ETHICS AND DISSEMINATION

The current study is approved by the Medical Ethics Research Committee Utrecht (reference number 21-014). Findings arising from this study will be disseminated in peer-reviewed journals, academic conferences and through patient organisations.

TRIAL REGISTRATION NUMBER

NL9011 and EudraCT 2020-005134-15.

Feasibility of a drop-in γ-probe for radioguided sentinel lymph detection in early-stage cervical cancer

Background

Minimally invasive radioguided sentinel lymph node (SLN) procedures, increasingly performed with robot-assisted laparoscopy, can benefit from using a drop-in γ-probe instead of the conventional rigid laparoscopic γ-probe. We evaluated the safety and feasibility of a tethered drop-in γ-probe system for SLN detection in patients with early-stage cervical cancer.

Methods

Ten patients with FIGO stage IA – IB2 or IIA1 cervical cancer scheduled for robot-assisted laparoscopic SLN procedure were included. All patients underwent preoperative 240 MBq technetium-99m nanocolloid (^99mTc) injection and SPECT/CT imaging. Intraoperatively the tethered drop-in γ-probe SENSEI® (Lightpoint Medical Ltd, Chesham, UK) was used for probe guided SLN detection, subsequently confirmed by the standard rigid laparoscopic γ-probe. Sentinel lymph node detection rates and anatomical SLN location were assessed. Surgeon questionnaires were used to assess usability.

Results

In all patients at least one SLN was successfully resected under guidance of the drop-in γ-probe (overall detection rate: 100%). Bilateral SLN detection rate with the drop-in γ-probe was 80%. Of the two patients with unilateral SLN detection only, one presented with an atypical SLN location at the aortic bifurcation that was detected only on SPECT/CT. The other patient had failed unilateral ^99mTc uptake. Combined use of preoperative SPECT/CT and drop-in γ-probe resulted in a bilateral detection rate of 90%. Similar to the drop-in γ-probe, overall and bilateral SLN detection rate of the rigid γ-probe was 100% and 80%, respectively. No significant discrepancy existed between the count rate of the drop-in and rigid laparoscopic γ-probe (p = 0.69). In total 21 SLN’s were detected with the drop-in γ-probes including all three tumor positive nodes. Because of wristed articulation of the robotic tissue grasper and possibility of autonomous probe control by the surgeon, maneuverability and control with the drop-in γ-probe were highly rated in surgeon questionnaires. No adverse events related to the intervention occurred.

Conclusions

Sentinel lymph node detection with a drop-in γ-probe is safe and feasible in patients with early-stage cervical cancer. Use of the drop-in γ-probe enhances maneuverability and surgical autonomy during robot-assisted SLN detection.

Trial registration Netherlands Trial Registry, NL9358. Registered 23 March 2021, https://www.trialregister.nl/trial/9358.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13550-022-00907-w.

Indocyanine green versus technetium-99m with blue dye for sentinel lymph node detection in early-stage cervical cancer: A systematic review and meta-analysis

Background

The fluorescent dye indocyanine green (ICG) has emerged as a promising tracer for intraoperative detection of sentinel lymph nodes (SLNs) in early‐stage cervical cancer. Although researchers suggest the SLN detection of ICG is equal to the more conventional combined approach of a radiotracer and blue dye, no consensus has been reached.

Aims

We aimed to assess the differences in overall and bilateral SLN detection rates with ICG versus the combined approach, the radiotracer technetium‐99m (^99mTc) with blue dye.

Methods and Results

We searched MEDLINE, Embase, and the Cochrane Library from inception to January 1, 2020 and included studies reporting on a comparison of SLN detection with ICG versus ^99mTc with blue dye in early‐stage cervical cancer. The overall and bilateral detection rates were pooled with random‐effects meta‐analyses.

From 118 studies retrieved seven studies (one cross‐sectional; six retrospective cohorts) were included, encompassing 589 patients. No significant differences were found in the pooled overall SLN detection rate of ICG versus ^99mTc with blue dye. Meta‐analyses of all studies showed ICG to result in a higher bilateral SLN detection rate than ^99mTc with blue dye; 90.3% (95%CI, 79.8‐100.0%) with ICG versus 73.5% (95%CI, 66.4‐80.6%) with 99mTc with blue dye. This resulted in a significant and clinically relevant risk difference of 16.6% (95%CI, 5.3‐28.0%). With sensitivity analysis, the risk difference of the bilateral detection rate maintained in favor of ICG but was no longer significant (13.2%, 95%CI −0.8‐27.3%).

Conclusion

ICG appears to provide higher bilateral SLN detection rates compared to ^99mTc with blue dye in patients with early‐stage cervical cancer. However, in adherence with the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) guidelines, the quality of evidence is too low to provide strong recommendations and directly omit the combined approach of ^99mTc with blue dye.

A colorful approach towards developing new nano-based imaging contrast agents for improved cancer detection

Providing physicians with new imaging agents to help detect cancer with better sensitivity and specificity has the potential to significantly improve patient outcomes. Development of new imaging agents could offer improved early cancer detection during routine screening or help surgeons identify tumor margins for surgical resection. In this study, we evaluate the optical properties of a colorful class of dyes and pigments that humans routinely encounter. The pigments are often used in tattoo inks and the dyes are FDA approved for the coloring of foods, drugs, and cosmetics. We characterized their absorption, fluorescence and Raman scattering properties in the hopes of identifying a new panel of dyes that offer exceptional imaging contrast. We found that some of these coloring agents, coined as "optical inks", exhibit a multitude of useful optical properties, outperforming some of the clinically approved imaging dyes on the market. The best performing optical inks (Green 8 and Orange 16) were further incorporated into liposomal nanoparticles to assess their tumor targeting and optical imaging potential. Mouse xenograft models of colorectal, cervical and lymphoma tumors were used to evaluate the newly developed nano-based imaging contrast agents. After intravenous injection, fluorescence imaging revealed significant localization of the new "optical ink" liposomal nanoparticles in all three tumor models as opposed to their neighboring healthy tissues (p < 0.05). If further developed, these coloring agents could play important roles in the clinical setting. A more sensitive imaging contrast agent could enable earlier cancer detection or help guide surgical resection of tumors, both of which have been shown to significantly improve patient survival.

Bio-inspired multimodal 3D endoscope for image-guided and robotic surgery

Image-guided and robotic surgery based on endoscopic imaging technologies can enhance cancer treatment by ideally removing all cancerous tissue and avoiding iatrogenic damage to healthy tissue. Surgeons evaluate the tumor margins at the cost of impeding surgical workflow or working with dimmed surgical illumination, since current endoscopic imaging systems cannot simultaneous and real-time color and near-infrared (NIR) fluorescence imaging under normal surgical illumination. To overcome this problem, a bio-inspired multimodal 3D endoscope combining the excellent characteristics of human eyes and compound eyes of mantis shrimp is proposed. This 3D endoscope, which achieves simultaneous and real-time imaging of three-dimensional stereoscopic, color, and NIR fluorescence, consists of three parts: a broad-band binocular optical system like as human eye, an optical relay system, and a multiband sensor inspired by the mantis shrimp's compound eye. By introducing an optical relay system, the two sub-images after the broad-band binocular optical system can be projected onto one and the same multiband sensor. A series of experiments demonstrate that this bio-inspired multimodal 3D endoscope not only provides surgeons with real-time feedback on the location of tumor tissue and lymph nodes but also creates an immersive experience for surgeons without impeding surgical workflow. Its excellent characteristics and good scalability can promote the further development and application of image-guided and robotic surgery.

Near-infrared fluorescence imaging compared to standard sentinel lymph node detection with blue dye in patients with vulvar cancer - a randomized controlled trial

OBJECTIVE

The aim of this study was to assess the superiority of ICG-^99mTc-nanocolloid for the intraoperative visual detection of sentinel lymph nodes (SLNs) in vulvar squamous cell carcinoma (VSCC) patients compared to standard SLN detection using ^99mTc-nanocolloid with blue dye.

METHODS

In this multicenter, randomized controlled trial, VSCC patients underwent either the standard SLN procedure or with the hybrid tracer ICG-^99mTc-nanocolloid. The primary endpoint was the percentage of fluorescent SLNs compared to blue SLNs. Secondary endpoints were successful SLN procedures, surgical outcomes and postoperative complications.

RESULTS

Forty-eight patients were randomized to the standard (n = 24) or fluorescence imaging group (n = 24) using ICG-^99mTc-nanocolloid. The percentage of blue SLNs was 65.3% compared to 92.5% fluorescent SLNs (p < 0.001). A successful SLN procedure was obtained in 92.1% of the groins in the standard group and 97.2% of the groins in the fluorescence imaging group (p = 0.33). Groups did not differ in surgical outcome, although more short-term postoperative complications were documented in the standard group (p = 0.041).

CONCLUSIONS

Intraoperative visual detection of SLNs in patients with VSCC using ICG-^99mTc-nanocolloid was superior compared to ^99mTc-nanocolloid and blue dye. The rate of successful SLN procedures between both groups was not significantly different. Fluorescence imaging has potential to be used routinely in the SLN procedure in VSCC patients to facilitate the search by direct visualization.

CLINICAL TRIAL REGISTRATION

Netherlands Trial Register (Trial ID NL7443).

Molecularly Imprinted Polymers: Antibody Mimics for Bioimaging and Therapy

Molecularly imprinted polymers (MIPs) are tailor-made chemical receptors that recognize and bind target molecules with a high affinity and selectivity. MIPs came into the spotlight in 1993 when they were dubbed "antibody mimics," and ever since, they have been widely studied for the extraction or trapping of chemical pollutants, in immunoassays, and for the design of sensors. Owing to novel synthesis strategies resulting in more biocompatible MIPs in the form of soluble nanogels, these synthetic antibodies have found favor in the biomedical domain since 2010, when for the first time, they were shown to capture and eliminate a toxin in live mice. This review, covering the years 2015-2020, will first describe the rationale behind these antibody mimics, and the different synthesis methods that have been employed for the preparation of MIPs destined for in vitro and in vivo targeting and bioimaging of cancer biomarkers, an emerging and fast-growing area of MIP applications. MIPs have been synthesized for targeting and visualizing glycans and protein-based cell receptors overexpressed in certain diseases, which are well-known biomarkers for example for tumors. When loaded with drugs, the MIPs could locally kill the tumor cells, making them efficient therapeutic agents. We will end the review by reporting how MIPs themselves can act as therapeutics by inhibiting cancer growth. These works mark a new opening in the use of MIPs for antibody therapy and even immunotherapy, as materials of the future in nanomedicine.

Nanoparticle-Based Platform for Activatable Fluorescence Imaging and Photothermal Ablation of Endometriosis

Endometriosis is a painful disorder where endometrium-like tissue forms lesions outside of the uterine cavity. Intraoperative identification and removal of these lesions are difficult. This study presents a nanoplatform that concurrently delineates and ablates endometriosis tissues using real-time near-infrared (NIR) fluorescence and photothermal therapy (PTT). The nanoplatform consists of a dye, silicon naphthalocyanine (SiNc), capable of both NIR fluorescence imaging and PTT, and a polymeric nanoparticle as a SiNc carrier to endometriosis tissue following systemic administration. To achieve high contrast during fluorescence imaging of endometriotic lesions, nanoparticles are constructed to be non-fluorescent prior to internalization by endometriosis cells. In vitro studies confirm that these nanoparticles activate the fluorescence signal following internalization in macaque endometrial stromal cells and ablate them by increasing cellular temperature to 53 ^° C upon interaction with NIR light. To demonstrate in vivo efficiency of the nanoparticles, biopsies of endometrium and endometriosis from rhesus macaques are transplanted into immunodeficient mice. Imaging with the intraoperative Fluobeam 800 system reveals that 24 h following intravenous injection, nanoparticles efficiently accumulate in, and demarcate, endometriotic grafts with fluorescence. Finally, the nanoparticles increase the temperature of endometriotic grafts up to 47 °C upon exposure to NIR light, completely eradicating them after a single treatment.

Technetium-99m-indocyanine green versus technetium-99m-methylene blue for sentinel lymph node biopsy in early-stage endometrial cancer

INTRODUCTION

The low accuracy of pre-operative imaging techniques for prediction of nodal status strengthens the relevance of sentinel lymph node (SLN) biopsy in endometrial cancer, although the optimal method for its detection is still under investigation. The increasing use of indocyanine green (ICG) has aroused concern about its enhanced visualization of lymphatic channels, which could lead to a specimen that is thought to be nodal tissue not subsequently yielding a lymph node on pathologic analysis ('empty node packet'). Our main objective was to compare the overall and bilateral detection rates for SLN biopsy using two combined techniques: technetium-99m-ICG (Tc-99m-ICG) versus technetium-99m-methylene blue (Tc-99m-MB). Our secondary aim was to compare the 'empty node packet' rates between the two cohorts.

METHODS

A prospective, non-randomized, single-center trial including patients diagnosed with endometrial cancer (any grade or histology) in pre-operative early stage, and operated on between February 2017 and July 2019. All tracers were injected intracervically. Pelvic and aortic lymphadenectomy were performed on patients at intermediate or high risk of recurrence pre-operatively. All SLNs were sent for intra-operative frozen section and afterwards processed following an ultrastaging protocol.

RESULTS

Eighty-four patients were included, 58% (n=49) in the Tc-99m-MB group and 42% (n=35) in the Tc-99m-ICG group. Overall detection rate was 93% and was not statistically different between the two groups. A better bilateral detection rate was observed among Tc-99m-ICG patients (69% vs 41%, p=0.012). The 'empty node packet' rate was 4% in the Tc-99m-ICG cohort and 0% in the Tc-99m-MB cohort (p=0.032).

DISCUSSION

Tc-99m-ICG is a feasible, safe technique for SLN biopsy in early-stage endometrial cancer, and appears to be superior in terms of bilateral detection to Tc-99m-MB. The addition of Tc-99m to ICG could decrease the rate of 'empty node packets' and better define the anatomic location of SLNs in patients with endometrial cancer.

Ultrasound assessment of translation of microbubbles driven by acoustic radiation force in a channel filled with stationary fluid

In this report, a method is proposed to quantify the translation of ultrasound contrast agent (UCA) microbubbles driven by acoustic radiation for the detection of channels filled with stationary fluid. The authors subjected UCA microbubbles in a channel with diameters of 0.1 and 0.5 mm to ultrasound pulses with a center frequency of 14.4 MHz. The translational velocity of the UCA microbubbles increased with the sound pressure and pulse repetition frequency (PRF) of the transmitted ultrasound. The mean translational velocity reached 0.75 mm/s at a negative peak sound pressure of 2.76 MPa and a PRF of 2 kHz. This trend agreed with the theoretical prediction, which indicated that the translational velocity was proportional to the square of the sound pressure and the PRF. Furthermore, an experiment was carried out with a phantom that mimics tissue and found that the proposed method aided in detection of the channel, even in the case of a low contrast-echo to tissue-echo ratio. The authors expect to develop the proposed method into a technique for detecting lymph vessels.

TMTP1-modified Indocyanine Green-loaded Polymeric Micelles for Targeted Imaging of Cervical Cancer and Metastasis Sentinel Lymph Node in vivo

Metastasis is one of the most threatening aspects of cervical cancer. We developed a method to intraoperatively map the primary tumor, metastasis and metastatic sentinel lymph nodes (SLNs), providing real-time intraoperative guidance in cervical cancer.

Methods: TMTP1, a tumor metastasis targeting peptide, was employed to modify the indocyanine green (ICG)-loaded poly (ethylene glycol)- poly (lactic-co-glycolic acid) (PEG-PLGA) micelles. The cervical cancer subcutaneous tumor model and lung metastasis model were established to determine the active targeting of ICG-loaded TMTP1-PEG-PLGA micelles (ITM) for the primary tumor and occult metastasis of cervical cancer. Human cervical cancer HeLa cells engineered by firefly luciferase were injected into the right hocks of BALB/c nude mice to develop the SLN metastasis model. The ITM and control ICG-loaded PEG-PLGA micelles (IM) were injected into the right hind footpads in the SLN metastasis model, and the migration and retention of micelles were recorded under near-infrared fluorescence. K14-HPV16 transgenic mice were also used to detect the image capability of ITM to target cancerous lesions.

Results: ITM could actively target imaging of the primary tumor and cervical cancer metastasis. ITM quickly diffused from the injection site to SLNs along lymphatic capillaries and remained in the SLNs for 12 h. Moreover, ITM specifically accumulated in the tumor metastatic SLNs (T-SLNs), which could be successfully distinguished from normal SLNs (N-SLNs).

Conclusion: ITM could achieve active targeting of the primary tumor, metastasis and T-SLNs, providing precise and real-time intraoperative guidance for cervical cancer.

Currently available and experimental dyes for intraoperative near-infrared fluorescence imaging of the ureters: a systematic review

Background

Iatrogenic ureteral injury (IUI) following abdominal surgery has a relatively low incidence, but is associated with high risks of morbidity and mortality. Conventional assessment of IUI includes visual inspection and palpation. This is especially challenging during laparoscopic procedures and has translated into an increased risk of IUI. The use of near-infrared fluorescent (NIRF) imaging is currently being considered as a novel method to identify the ureters intraoperatively. The aim of this review is to describe the currently available and experimental dyes for ureter visualization and to evaluate their feasibility of using them and their effectiveness.

Methods

This article adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standard for systematic reviews. A systematic literature search was performed in the PubMed database. All included articles were screened for eligibility by two authors. Three clinical trial databases were consulted to identify ongoing or completed unpublished trials. Risk of bias was assessed for all articles.

Results

The search yielded 20 articles on ureter visualization. Two clinically available dyes, indocyanine green (ICG) and methylene blue (MB), and eight experimental dyes were described and assessed for their feasibility to identify the ureter. Two ongoing clinical trials on CW800-BK and one trial on ZW800-1 for ureter visualization were identified.

Conclusions

Currently available dyes, ICG and MB, are safe, but suboptimal for ureter visualization based on the route of administration and optical properties, respectively. Currently, MB has potential to be routinely used for ureter visualization in most patients, but (cRGD-)ZW800-1 holds potential for this role in the future, owing to its exclusive renal clearance and the near absence of background. To assess the benefit of NIRF imaging for reducing the incidence of IUI, larger patient cohorts need to be examined.

Electronic supplementary material

The online version of this article (10.1007/s10151-019-01973-4) contains supplementary material, which is available to authorized users.

Optical method to extract the reduced scattering coefficient from tissue: theory and experiments

Tissues are considered challenging in terms of structure and composition analysis due to their tendency to multiple scatter the incident light. One of the most common theories for extracting optical properties of tissue is diffusion reflection (DR). In this Letter, we propose a new paradigm for estimating the reduced scattering coefficient of a medium from the reflected light phase. The technique is a modified DR theory wherein the phase is calculated by the product of the wavenumber and the average pathlength. This theory is supported by the reconstructed phase of tissue-like phantom experiments from an iterative algorithm.

Non-Covalently Pre-Assembled High-Performance Near-Infrared Fluorescent Molecular Probes for Cancer Imaging

New fluorescent molecular probes, which can selectively target specific cell surface receptors, are needed for microscopy, in vivo imaging, and image guided surgery. The preparation of multivalent probes using standard synthetic chemistry can be a laborious process due to low reaction yields caused by steric effects. In this study, fluorescent molecular probes were prepared by a programmed non-covalent pre-assembly process that used a near-infrared fluorescent squaraine dye to thread a macrocycle bearing a cyclic arginine-glycine-aspartate peptide antagonist (cRGDfK) as a cancer targeting unit. Cell microscopy studies using OVCAR-4 (ovarian cancer) and A549 (lung cancer) cells that express high levels of the integrin αvβ3 or αvβ5 receptors, respectively, revealed a multivalent cell targeting effect. That is, there was comparatively more cell uptake of a pre-assembled probe equipped with two copies of the cRGDfK antagonist than a pre-assembled probe with only one appended cRGDfK antagonist. The remarkably high photostability and low phototoxicity of these near-infrared probes allowed for acquisition of long-term fluorescence movies showing endosome trafficking in living cells. In vivo near-infrared fluorescence imaging experiments compared the biodistribution of a targeted and untargeted probe in a xenograft mouse tumor model. The average tumor-to-muscle ratio for the pre-assembled targeted probe was 3.6 which matches the tumor targeting performance reported for analogous cRGDfK-based probes that were prepared entirely by covalent synthesis. The capability to excite these pre-assembled near-infrared fluorescent probes with blue or deep-red excitation light makes it possible to determine if a target site is located superficially or buried in tissue, a probe performance feature that is likely to be very helpful for eventual applications such as fluorescence guided surgery.

A practical guide for the use of indocyanine green and methylene blue in fluorescence-guided abdominal surgery

Near-infrared (NIR) fluorescence imaging is gaining clinical acceptance over the last years and has been used for detection of lymph nodes, several tumor types, vital structures and tissue perfusion. This review focuses on NIR fluorescence imaging with indocyanine green and methylene blue for different clinical applications in abdominal surgery with an emphasis on oncology, based on a systematic literature search. Furthermore, practical information on doses, injection times, and intraoperative use are provided.

Correlation of Isotope Count With Sentinel Node Positivity in Vulvar Cancer

OBJECTIVE

Sentinel node biopsy (SNB) has become standard of care in early stage vulvar cancer. As the correlation of isotope count with the presence of metastases remains unclear, often several active nodes are excised per groin. This can result in increased morbidity in node-negative disease despite of SNB. In the current analysis, we assess whether resection of the hottest node could be sufficient to detect sentinel lymph node (SLN) metastasis.

METHODS

Patients with primary vulvar cancer receiving an SNB with radioactive tracer at the University Medical Center Hamburg-Eppendorf between 2008 and 2015 were evaluated.

RESULTS

A total of 145 patients with SNB were analyzed; thereof, 144 underwent bilateral SNB, resulting in 289 analyzed groins. A median of 2 SLNs (range, 1-7) per groin were removed. From 94 (32.5%) of 289 groins, more than 2 SLNs were excised. Median overall SLN isotope count was 1400 cps. In 50 groins, a positive SLN was detected (unilateral in 38 patients, bilateral in 6). The median number of positive SLN per groin was 1 (range, 1-4). The SLN with the highest isotope count carried metastases in 36 (78.3%) of 46 groins (in 4 cases, the highest count was unknown). In 10 (21.7%) of 46 positive groins, the SLN with the highest count was not the metastatic SLN (9/10 second highest count). Median count of these 10 SLN was 60% of the highest count with a range from 11.0% to 74.0%.

CONCLUSIONS

The highest isotope count does not reliably detect the positive SLN in vulvar cancer. To prevent mostly fatal groin recurrences, surgeons should continue to remove all SLN accumulating relevant radioactive tracer over background activity.

Self-Calibration Phenomenon for Near-Infrared Clinical Measurements: Theory, Simulation, and Experiments

An irradiated turbid medium scatters the light in accordance to its optical properties. Near-infrared (NIR) clinical methods, which are based on spectral-dependent absorption, suffer from an inherent error due to spectral-dependent scattering. We present here a unique spatial point, that is, iso-pathlength (IPL) point, on the surface of a tissue at which the intensity of re-emitted light remains constant. This scattering-indifferent point depends solely on the medium geometry. On the basis of this natural phenomenon, we suggest a novel optical method for self-calibrated clinical measurements. We found that the IPL point exists in both cylindrical and semi-infinite tissue geometries (Supporting Information, Video file). Finally, in vivo human finger and mice measurements are used to validate the crossing point between the intensity profiles of two wavelengths. Hence, measurements at the IPL point yield an accurate absorption assessment while eliminating the scattering dependence. This finding can be useful for oxygen saturation determination, NIR spectroscopy, photoplethysmography measurements, and a wide range of optical sensing methods for physiological aims.

High expression of integrin αvβ3 enables uptake of targeted fluorescent probes into ovarian cancer cells and tumors

The cell line OVCAR-4 was recently ranked as one of the most representative cell lines for high grade serous ovarian cancer (HGSOC). However, little work has been done to assess the susceptibility of OVCAR-4 cells and tumors to the more common types of molecular targeting. Proteome profiles suggest OVCAR-4 express high levels of integrin αvβ3 receptors. Using flow cytometry with fluorescent antibodies we determined that OVCAR-4 cells have high number of integrin αvβ3 receptors ([9.8 ± 2.5] × 10⁴/cell) compared to the well-characterized cell line U87-MG ([5.2 ± 1.4] × 10⁴/cell). However, OVCAR-4 cells also have roughly three times the surface area of U87-MG cells, so the average αvβ3 receptor density is actually lower (11 ± 3 versus 18 ± 6 receptors/µm²). A series of new fluorescent molecular probes was prepared with structures comprised of a deep-red squaraine fluorophore (∼680 nm emission) covalently attached to zero, one, or two cyclic pentapeptide cRGD sequences for integrin targeting. Microscopy studies showed that uptake of the divalent probe into cultured OVCAR-4 cells was 2.2 ± 0.4 higher than the monovalent probe, which in turn was 2.2 ± 0.4 higher than the untargeted probe. This probe targeting trend was also seen in OVCAR-4 mouse tumor models. The results suggest that clinically relevant OVCAR-4 cells can be targeted using molecular probes based on αvβ3 integrin receptor antagonists such as the cRGD peptide. Furthermore, deep-red fluorescent cRGD-squaraine probes have potential as targeted stains of cancerous tissue associated with HGSOC in surgery and pathology settings.

Indocyanine green-incorporating nanoparticles for cancer theranostics

Indocyanine green (ICG) is a near-infrared dye that has been used in the clinic for retinal angiography, and defining cardiovascular and liver function for over 50 years. Recently, there has been an increasing interest in the incorporation of ICG into nanoparticles (NPs) for cancer theranostic applications. Various types of ICG-incorporated NPs have been developed and strategically functionalised to embrace multiple imaging and therapeutic techniques for cancer diagnosis and treatment. This review systematically summaries the biodistribution of various types of ICG-incorporated NPs for the first time, and discusses the principles, opportunities, limitations, and application of ICG-incorporated NPs for cancer theranostics. We believe that ICG-incorporated NPs would be a promising multifunctional theranostic platform in oncology and facilitate significant advancements in this research-active area.

Intraoperative Near-Infrared Fluorescence Imaging of Multiple Pancreatic Neuroendocrine Tumors: A Case Report

Multiple endocrine neoplasia type 1 syndrome can feature pancreatic neuroendocrine lesions that have the potential to degenerate into malignancies (pancreatic neuroendocrine tumors [PNETs]). Resection is required in selected cases and aims to cure patients and to prevent metastasis. Preoperative imaging is important to assess the number, size, and location of PNETs. However, sensitivity of preoperative imaging modalities to detect small lesions can be rather disappointing. This makes intraoperative reassessment of the pancreas crucial. Methylene blue (MB) accumulates in neuroendocrine lesions after intravenous administration. Methylene blue emits fluorescence of approximately 700 nm and can be visualized using a dedicated near-infrared (NIR) fluorescence imaging system. We present a 58-year-old male patient with multiple endocrine neoplasia type 1 syndrome and 2 lesions suspected as PNETs identified during regular follow-up. Intraoperative administration of MB allowed successful NIR fluorescence imaging of multiple lesions missed by preoperative imaging. After confirmation by intraoperative ultrasound, this new finding led to a major change in treatment: from enucleations to total pancreatectomy. Histopathologic examination confirmed that the fluorescent lesions were indeed neuroendocrine lesions ranging from microadenomas to PNETs. This case demonstrates that intraoperative assessment of neuroendocrine lesions can be improved by intraoperative NIR fluorescence imaging using MB, a safe and relatively easy technique.

Intraoperative imaging of folate receptor alpha positive ovarian and breast cancer using the tumor specific agent EC17

Introduction

Intraoperative fluorescence imaging of the folate-receptor alpha (FRα) could support completeness of resection in cancer surgery. Feasibility of EC17, a FRα-targeting agent that fluoresces at 500nm, was demonstrated in a limited series of ovarian cancer patients. Our objective was to evaluate EC17 in a larger group of ovarian cancer patients. In addition, we assessed the feasibility of EC17 in patients with breast cancer.

Methods

Two-to-three hours before surgery 0.1mg/kg EC17 was intravenously administered to 12 patients undergoing surgery for ovarian cancer and to 3 patients undergoing surgery for biopsy-proven FRα-positive breast cancer. The number of lesions/positive margins detected with fluorescence and concordance between fluorescence and tumor- and FRα-status was assessed in addition to safety and pharmacokinetics.

Results

Fluorescence imaging in ovarian cancer patients allowed detection of 57 lesions of which 44 (77%) appeared malignant on histopathology. Seven out of these 44 (16%) were not detected with inspection/palpation. Histopathology demonstrated concordance between fluorescence and FRα- and tumor status. Fluorescence imaging in breast cancer patients, allowed detection of tumor-specific fluorescence signal. At the 500nm wavelength, autofluorescence of normal breast tissue was present to such extent that it interfered with tumor identification.

Conclusions

FRα is a favorable target for fluorescence-guided surgery as EC17 produced a clear fluorescent signal in ovarian and breast cancer tissue. This resulted in resection of ovarian cancer lesions that were otherwise not detected. Notwithstanding, autofluorescence caused false-positive lesions in ovarian cancer and difficulty in discriminating breast cancer-specific fluorescence from background signal. Optimization of the 500nm fluorophore, will minimize autofluorescence and further improve intraoperative tumor detection.

Sentinel lymph node mapping in gynecological oncology

The intraoperative mapping of sentinel lymph nodes (SLNs) is part of the treatment strategy for a number of types of tumor. To retrospectively compare results from the mapping of pelvic SLNs for gynecological oncology, using distinct dyes, the present review was conducted to determine the clinical significance of SLN mapping for gynecological oncology. In addition, the present study aimed at identifying an improved choice for SLN mapping tracers in clinical application. Each dye exhibits demerits when applied in the clinical environment. The combination of radioisotopes and blue dyes was identified to exhibit the most accurate detection rate of SLN drainage of gynecological oncology. However, contrast agents were unable to identify whether a SLN is positive or negative for metastasis prior to pathologic examination; additional studies are required.

Laparoscopic Sentinel Node Mapping in Cervical and Endometrial Malignancies: A Case-Control Study Comparing Two Near-Infrared Fluorescence Systems

STUDY OBJECTIVE

The goal of this study was to evaluate the intraoperative and perioperative surgical outcomes of 2 different florescence systems commonly used for sentinel lymph node (SLN) mapping in women with early-stage cervical cancer or endometrial cancer.

DESIGN

Case-control study (Canadian Task Force classification II-2).

SETTING

The Gynecology Oncology Surgical Unit of the San Gerardo Hospital, Italy.

PATIENTS

Thirty-four consecutive women with early stage-cervical cancer (stage IA-1B1) or apparent confined stage I endometrial cancer were included in the study.

INTERVENTIONS

Between October 2016 and May 2017, 34 patients underwent laparoscopic surgery with SLN mapping using indocyanine green dye: 22 women were mapped with the Storz 1S system (Karl Storz Endoscopy, Tuttlingen, Germany; Group A), whereas 12 women underwent planned surgery with the Novadaq PinPoint system (Novadaq, Mississauga, Ontario, Canada; Group B).

MEASUREMENT AND MAIN RESULTS

We compared the surgical and perioperative outcomes of Group A and Group B. Patients in Group B had a shorter duration of the SLN mapping time than those in Group A (p = .0003). The median number of SLNs removed was 2 (range, 0-5) in Group A and 2 (range, 1-3) in Group B (p = .501). Bilateral mapping was 77.3% in Group A and 83.3% in Group B (p = .334), respectively. No differences were recorded in terms of body mass index, length of hospital stay, type of tumor, bilateral mapping, or number of lymph nodes removed. Body mass index was found to have no impact on the duration of the mapping (p = .353).

CONCLUSION

From our preliminary experience we can conclude that both fluorescence systems are valid and applicable for SLN detection in the case of early-stage cervical or endometrial cancer. The PinPoint system seems to allow surgeons easier and faster identification of the SLNs, particularly in endometrial cancer patients.

Early ovarian cancer surgery with indocyanine-green-guided targeted compartmental lymphadenectomy (TCL, pelvic part)

OBJECTIVE

Para-aortic indocyanine-green (ICG)-guided targeted compartmental lymphadenectomy is feasible in early ovarian cancer; systematic pelvic and para-aortic lymphadenectomy could potentially be avoided if thoroughly investigated sentinel nodes could predict whether residual nodes will be involved or free of disease. In contrast to advanced ovarian cancer, where the therapeutic potential of lymphadenectomy will soon be clarified by the results of the Arbeitsgemeinschaft Gynäkologische Onkologie lymphadenectomy in ovarian neoplasms (AGO LION) trial, systematic lymphadenectomy seems to be mandatory for diagnostic and also therapeutic purposes in early ovarian cancer. Sentinel node biopsy or resection of the regional lymphatic network may reduce morbidity compared to systematic lymphadenectomy as shown already for other entities. Apart from the ovarian mesonephric pathway, a second Müllerian uterine pathway exists for lymphatic drainage of the ovary. Lymphatic valves apparently do not exist at this level of the utero-ovarian network since injection of radioactivity into the ovarian ligaments also labelled pelvic nodes.

METHODS

We applied ICG using 4×0.5 mL of a 1.66 mg/mL ICG solution for transcervical injection into the fundal and midcorporal myometrium at each side [10] instead of injection into the infundibulopelvic ligament, since the utero-ovarian drainage was intact.

RESULTS

In this case a 1.8 cm cancer of the right ovary was removed in continuity with its draining lymphatic vessels and at least the first 2 sentinel nodes in each channel "en bloc" as shown in this video for the pelvic part, consistent with the loco-regional ontogenetic approach.

CONCLUSION

This could potentially avoid most of systematic lymphadenectomies in early ovarian cancer.

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

BACKGROUND

Several studies demonstrated that intraoperative near-infrared fluorescence (NIRF) imaging using indocyanine green (ICG) identifies (sub)capsular colorectal liver metastases (CRLM) missed by other techniques. It is unclear if this results in any survival benefit. This study evaluates long-term follow-up after NIRF-guided resection of CRLM using ICG.

METHODS

First, patients undergoing resection of CRLM with or without NIRF imaging were analyzed retrospectively. Perioperative details, liver-specific recurrence-free interval and overall survival were compared. Second, the prognosis of patients in whom additional metastases were identified solely by NIRF was studied.

RESULTS

Eighty-six patients underwent resection with NIRF imaging and 87 without. In significantly more patients of the NIRF imaging cohort additional metastases were identified during surgery (25% vs. 13%, p = 0.04). Tumors identified solely by NIRF imaging were significantly smaller compared to additional metastases identified also by inspection, palpation or intraoperative ultrasound (3.2 ± 1.8 mm vs. 7.4 ± 2.6 mm, p < 0.001). Liver-specific recurrence-free survival at 4 years was 47% with NIRF imaging and 39% without (hazard ratio at multivariate analysis 0.73, 95% CI 0.42-1.28, p = 0.28). Overall survival at 4 years was 62% and 59%, respectively (p = 0.79). No liver recurrences occurred within 3 years follow-up in 52% of patients in whom additional metastases were resected based on only NIRF imaging.

CONCLUSIONS

This study suggests that NIRF imaging identifies significantly more and smaller tumors during resection of CRLM, preventing recurrences in a subset of patients. Given its safety profile and low expense, routine use can be considered until tumor targeting fluorescent tracers are clinically available.

Sentinel Node and Ovarian Tumors: A Series of 20 Patients

Objective

Intraoperative detection of ovarian sentinel nodes has been shown to be feasible. We examined the detection rate and locations of sentinel nodes in patients with ovarian tumors. We also aimed to assess the reliability of sentinel node method in predicting regional lymph node metastasis.

Methods

Twenty patients scheduled for laparotomy because of a pelvic mass were recruited to the study. In the beginning of the laparotomy, radioisotope and blue dye were injected under the serosa next to the junction of the ovarian tumor and suspensory ligament. The number and locations of the hot and/or blue nodes/spots were recorded during the operation. If the tumor was malignant according to the frozen section, systematic lymphadenectomies were performed, the sentinel nodes sampled separately, and their status compared with other regional lymph nodes.

Results

Eleven patients had a right-sided ovarian tumor, 7 patients a left-sided tumor, and 2 patients had bilateral tumors. A median of 2 sentinel nodes/locations per patient (range, 1–3) were found. Sixty percent of all sentinel nodes were located in the para-aortic region only, compared with 30% in both para-aortic and pelvic areas and 10% in pelvic area only. Both unilateral and bilateral locations were found. In 83% of the cases with more than 1 sentinel node location, they were located in separate anatomical regions. In 3 patients, systematic lymphadenectomies were performed. One of them had nodal metastases in 2 regions and also a metastasis in 1 of her 2 sentinel nodes in 1 of those regions.

Conclusions

In patients with ovarian tumor(s), the detection of sentinel nodes is feasible. They are located in different anatomic areas both ipsilaterally and contralaterally, although most of them are found in the para-aortic region. The reliability of the sentinel node concept should be evaluated in the framework of a multicenter trial.

Fluorescence Imaging Topography Scanning System for intraoperative multimodal imaging

Fluorescence imaging is a powerful technique with diverse applications in intraoperative settings. Visualization of three dimensional (3D) structures and depth assessment of lesions, however, are oftentimes limited in planar fluorescence imaging systems. In this study, a novel Fluorescence Imaging Topography Scanning (FITS) system has been developed, which offers color reflectance imaging, fluorescence imaging and surface topography scanning capabilities. The system is compact and portable, and thus suitable for deployment in the operating room without disturbing the surgical flow. For system performance, parameters including near infrared fluorescence detection limit, contrast transfer functions and topography depth resolution were characterized. The developed system was tested in chicken tissues ex vivo with simulated tumors for intraoperative imaging. We subsequently conducted in vivo multimodal imaging of sentinel lymph nodes in mice using FITS and PET/CT. The PET/CT/optical multimodal images were co-registered and conveniently presented to users to guide surgeries. Our results show that the developed system can facilitate multimodal intraoperative imaging.

Long wavelength excitable near-infrared fluorescent nanoparticles with aggregation-induced emission characteristics for image-guided tumor resection

Near infrared (NIR) fluorescence imaging (700-900 nm) is a promising technology in preclinical and clinical tumor diagnosis and therapy. The availability of excellent NIR fluorescent contrast agents is still the main barrier to implementing this technology. Herein, we report the design and synthesis of two series of NIR fluorescent molecules with long wavelength excitation and aggregation-induced emission (AIE) characteristics by fine-tuning their molecular structures and substituents. Further self-assembly between an amphiphilic block co-polymer and the obtained AIE molecules leads to AIE nanoparticles (AIE NPs), which have absorption maxima at 635 nm and emission maxima between 800 and 815 nm with quantum yields of up to 4.8% in aggregated states. In vitro and in vivo toxicity results demonstrate that the synthesized AIE NPs are biocompatible. Finally, the synthesized AIE NPs have been successfully used for image-guided tumor resection with a high tumor-to-normal tissue signal ratio of 7.2.

Surgical treatment of early ovarian cancer with compartmental resection of regional lymphatic network and indocyanine-green-guided targeted compartmental lymphadenectomy (TCL, paraaortic part)

Objective

Whether pelvic and para-aortic lymphadenectomy is of therapeutic benefit in advanced ovarian cancer will remain unclear until the publication of the Arbeitsgemeinschaft Gynäkologische Onkologie lymphadenectomy in ovarian neoplasms (AGO LION) trial. In early ovarian cancer, however, lymphadenectomy seems mandatory for diagnostic and also therapeutic reasons [123].

Methods

Complete systematic lymphadenectomy is accompanied by morbidity which may be reduced by sentinel node biopsy already established for several solid tumors [456]. In ovarian cancer there are 2 main pathways in lymphatic drainage: along the ovarian vessels to the para-aortic nodes and the uterine vessels to the iliac lymph compartments [7]. Following injection of radioactive dye into the ovarian ligaments this could be confirmed suggesting that there is bidirectional flow at this level of the ovarian and uterine lymphatic pathways [8]. Indocyanine-green-guided (ICG) injection to the uterine corpus seems to be equally effective in labelling the “uterine Müllerian” and the “ovarian mesonephric” lymphatic drainage of the ovary [910].

Results

This technique [9] was applied and will be outlined in the video showing the procedure with respect to the para-aortic lymphatic drainage. Isolated sentinel node biopsy and tumor excision will not resect the organ compartment together with its super-ordinated draining lymphatic system at risk.

Conclusion

Thus, the authors suggest to remove the malignancy together with its draining lymphatic vessels and at least the first 2 sentinel nodes in each channel en bloc; we propose to analyze this procedure consistent with the ontogenetic approach [1112] with respect to diagnostic accuracy and loco-regional control. This could potentially avoid most of systematic lymphadenectomies in early ovarian cancer.

Near-infrared fluorescence laparoscopy of the cystic duct and cystic artery: first experience with two new preclinical dyes in a pig model

Background

Imaging techniques that enhance visualisation of the anatomy may help prevent bile duct injury. Near-Infrared Fluorescence Imaging is such a technique. Previous experiments with ICG have shown that illumination of the extra-hepatic bile ducts is feasible. Yet, there is room for improvement in the visualisation of the target as compared to the background. Experiments with IRDye^® 800CW show promising results. However, this dye is too expensive for routine clinical use. The aim of this study is to test the first applicability of two newly developed preclinical dyes regarding intraoperative imaging of the cystic duct and cystic artery, compared with IRDye^® 800CW.

Methods

Laparoscopic cholecystectomy was performed in three pigs, using a laparoscopic fluorescence imaging system. Each pig received 6 mg of one of the fluorescent dyes (1 mg/mL; IRDye^® 800CW, IRDye^® 800BK or IRDye^® 800NOS) by intravenous injection. Intraoperative recognition of the biliary system and cystic artery was registered at set time points. All procedures were digitally recorded, and the target to background ratio (TBR) was determined to assess the fluorescence signal.

Results

With all three fluorescent dyes, the cystic artery was directly visualised. For the visualisation of the cystic duct, 15, 34 and 30 min were needed using IRDye^® 800BK, IRDye^® 800NOS and IRDye^® 800CW, respectively. The maximum TBR of the cystic duct was the highest with IRDye^® 800NOS (4.20) after 36 min, compared to 2.45 for IRDye^® 800BK and 2.15 for IRDye^® 800CW, both after 45 min. There were no adverse events.

Conclusion

IRDye^® 800BK and IRDye^® 800NOS seem to be good alternatives for IRDye^® 800CW for the visualisation of the cystic duct and cystic artery in pigs.

Sentinel lymph node mapping in patients with stage I endometrial carcinoma: a focus on bilateral mapping identification by comparing radiotracer Tc99m with blue dye versus indocyanine green fluorescent dye

PURPOSE

The aim of this study was to compare technetium radiocolloid (Tc99m) + blue dye (BD) versus Indocyanine green (ICG) fluorescent dye in terms of the overall detection rate and bilateral sentinel lymph node (SLN) mapping in patients with endometrial carcinoma.

METHODS

Patients from five European centers with apparently confined clinical stage I endometrial cancer were reviewed. A comparison was made between women who received SLN mapping with pelvic and/or aortic lymphadenectomy (LND), and women who underwent SLN algorithm (SA), was also performed between the two groups.

RESULTS

Three hundred and forty-two (342) women were involved (147 in the Tc99m + BD group and 195 in the ICG group). The overall detection rate of SLN biopsy was 97.3% (143/147) for women in the Tc99m + BD group and 96.9% (189/195) for women in the ICG group (p = 0.547). The bilateral mapping rate for ICG was 84.1%-significantly higher with respect to the 73.5% obtained with Tc99m + BD (p = 0.007). No differences in overall sensitivity (OS) and overall false negative rate (FNR) were seen between LND and SA (p value = 0.311), whereas the negative predictive value (NPV) was in favor of SA group (p value = 0.030).

CONCLUSIONS

In this study, fluorescent mapping using ICG resulted equivalent to the standard combined radiocolloid and BD, but real-time SLN mapping achieves a higher bilateral detection rate. The added value that this fast emerging technology promises to give certainly warrants future studies to further consolidate the advantages there are over the standard technique.

Efficacious fluorescence turn-on probe for high-contrast imaging of human cells overexpressing quinone reductase activity

A turn-on substrate probe is activated by an oxidoreductase, offering fluorescence images of cancer cells with unprecedented positive signal-to-negative background ratios.

Synthesis of Near-Infrared Fluorescent Two-Photon-Absorbing Fluorenyl Benzothiadiazole and Benzoselenadiazole Derivatives

A series of dyes 2-5 based on 5-thienyl-2,1,3-benzothiadiazole and 5-thienyl-2,1,3-benzoselenadiazole cores were synthesized as near-infrared-emitting two-photon-absorbing fluorophores. Fluorescence maxima wavelengths as long as 714 nm and quantum yields as high as 0.67 were realized. The fluorescence quantum yields of dyes 2-4 were nearly constant, regardless of solvent polarity. These diazoles exhibited large Stokes shifts (>110 nm) and high two-photon figure of merit. Cells incubated on a 3D scaffold with probe 4 (encapsulated in Pluronic micelles) exhibited bright fluorescence, enabling 3D two-photon fluorescence imaging to a depth of 100 μm.

Lymphatic metastasis of gallbladder cancer: Present and future

Lymphatic metastasis is the most common way of metastasis in gallbladder cancer (GBC), and it is also one of the important factors influencing prognosis. Therefore, it is important to elucidate the lymphatic drainage pathways, group the metastatic lymph nodes, assess the extent of lymphadenectomy, and identify relevant predictors of lymphatic metastasis. The development of lymph node tracer technique has greatly improved the surgical procedure, and exploration of the molecular mechanisms of lymphatic metastases may provide new therapeutic targets. In the current review, we discuss the lymphatic drainage pathways as well as the substation, predictors, tracers and mechanisms of lymphatic metastasis of GBC.

Near-infrared Fluorescence-guided Sentinel Node Mapping of the Ovary With Indocyanine Green in a Minimally Invasive Setting: A Feasible Study

Sentinel lymph node (SLN) mapping has increased its feasibility in both early-stage cervical and endometrial cancer. There are few SLN studies regarding the ovary because of the risk of tumor dissemination and perhaps because the ovary represents an inconvenient site for injection. In this preliminary study, we have shown the feasibility of SLN mapping of the ovary with indocyanine green during laparoscopic retroperitoneal aortic surgical staging. The 10 women who were included in this study underwent aortic with pelvic laparoscopic staging, which included SLN biopsy, extrafascial total hysterectomy, and bilateral salpingo-oophorectomy in case of an ovarian tumor. The fluorescent dye was injected on the dorsal and ventral side of the proper ovarian ligament and the suspensory ligament, close to the ovary and just underneath the peritoneum. In all cases except 1, SLNs were detected soon after the injection in the aortic compartment and in 3 cases also in the common iliac region. Only 1 intraoperative complication occurred: a superficial lesion of the vena cava that was recovered with a laparoscopic suture. Laparoscopic ovarian SLN mapping performed by means of an injection of indocyanine green fluorescent tracer in the ovarian ligaments seems feasible and promising. Further investigation are encouraged and necessary to evaluate the possible applications of this new technique for staging patients with early-stage ovarian cancer.

Optimizing Strategies for Sentinel Lymph Node Mapping in Early-Stage Cervical and Endometrial Cancer: Comparison of Real-Time Fluorescence With Indocyanine Green and Methylene Blue

OBJECTIVE

This retrospective study aimed to compare the sentinel lymph node (SLN) mapping results of methylene blue (MB) and indocyanine green (ICG) in women with early-stage endometrial or cervical cancer.

METHODS

From August 2011 to March 2015, all consecutive patients with stage I endometrial or cervical cancer who underwent SLN mapping with intracervical injection of MB or ICG using a 22-gauge spinal needle were included in the study. Radical or simple hysterectomy with bilateral pelvic and/or aortic lymphadenectomy was performed after SLN mapping.

RESULTS

Overall, 81 women (64 women with endometrial cancer and 17 women with cervical cancer) underwent surgery, including SLN mapping. Sixty-five patients (80%) underwent minimally invasive surgery. The overall detection rate was 84% (34 of 38) and 100% (43 of 43) for MB and ICG, respectively (P = 0.041). Bilateral SLN detection was higher in the ICG group than in the MB group (88% vs 50; P = 0.002). Eleven patients (13.5%) were found to have positive nodes with at least 1 positive SLN. The sensitivity and negative predictive value of SLN were 100%.

CONCLUSIONS

Real-time florescence mapping with ICG shows better overall detection rate and bilateral mapping than MB alone. In our pilot study, the differences are statistically significant. The higher number of bilateral mapping of ICG may increase the quality of life and recovery of women by reducing the need for complete lymphadenectomy.

Understanding Lymphatic Drainage Pathways of the Ovaries to Predict Sites for Sentinel Nodes in Ovarian Cancer

Supplemental digital content is available in the text.

Objective

In ovarian cancer, detection of sentinel nodes is an upcoming procedure. Perioperative determination of the patient’s sentinel node(s) might prevent a radical lymphadenectomy and associated morbidity. It is essential to understand the lymphatic drainage pathways of the ovaries, which are surprisingly up till now poorly investigated, to predict the anatomical regions where sentinel nodes can be found. We aimed to describe the lymphatic drainage pathways of the human ovaries including their compartmental fascia borders.

Methods

A series of 3 human female fetuses and tissues samples from 1 human cadaveric specimen were studied. Immunohistochemical analysis was performed on paraffin-embedded transverse sections (8 or 10 μm) using antibodies against Lyve-1, S100, and α-smooth muscle actin to identify the lymphatic endothelium, Schwann, and smooth muscle cells, respectively. Three-dimensional reconstructions were created.

Results

Two major and 1 minor lymphatic drainage pathways from the ovaries were detected. One pathway drained via the proper ligament of the ovaries (ovarian ligament) toward the lymph nodes in the obturator fossa and the internal iliac artery. Another pathway drained the ovaries via the suspensory ligament (infundibulopelvic ligament) toward the para-aortic and paracaval lymph nodes. A third minor pathway drained the ovaries via the round ligament to the inguinal lymph nodes. Lymph vessels draining the fallopian tube all followed the lymphatic drainage pathways of the ovaries.

Conclusions

The lymphatic drainage pathways of the ovaries invariably run via the suspensory ligament (infundibulopelvic ligament) and the proper ligament of the ovaries (ovarian ligament), as well as through the round ligament of the uterus. Because ovarian cancer might spread lymphogenously via these routes, the sentinel node can be detected in the para-aortic and paracaval regions, obturator fossa and surrounding internal iliac arteries, and inguinal regions. These findings support the strategy of injecting tracers in both ovarian ligaments to identify sentinel nodes.

Image-guided tumor surgery: will there be a role for fluorescent nanoparticles?

Image-guided surgery (IGS) using fluorescent nanoparticles (NPs) has the potential to substantially impact patient treatment. The use of fluorescence imaging provides surgeons with real-time feedback on the location of diseased tissue using safe, low-cost imaging agents and instrumentation. Fluorescent NPs are likely to play a role as they are capable of taking advantage of the enhanced permeability and retention (EPR) effect and can be modified to avoid clearance, increase circulation time, and specifically target tumors. Clinical trials of IGS using the FDA-approved fluorophores indocyanine green and methylene blue have already shown preliminary successes, and incorporation of fluorescent NPs will likely improve detection by providing higher signal to background ratio and reducing false-positive rates through active targeting. Preclinical development of fluorescent NP formulations is advancing rapidly, with strategies ranging from passive targeting to active targeting of cell surface receptors, creating pH-responsive NPs, and increasing cell uptake through cleavable proteins. This collective effort could lead to clinical trials using fluorescent NPs in the near future. WIREs Nanomed Nanobiotechnol 2016, 8:498-511. doi: 10.1002/wnan.1381 For further resources related to this article, please visit the WIREs website.

Groin lymph node detection and sentinel lymph node biopsy in vulvar cancer

OBJECTIVE

To identify suitable diagnostic tools and evaluate the efficacy of sentinel lymph node (SLN) biopsy for inguinal lymph node metastasis in vulvar cancer.

METHODS

Data from 41 patients with vulvar cancer were evaluated retrospectively, including magnetic resonance imaging (MRI) measurements, SLN biopsy status, groin lymph node metastasis, and prognosis.

RESULTS

SLN biopsy was conducted in 12 patients who had stage I to III disease. Groin lymphadenectomy was omitted in five of the nine patients with negative SLNs. All SLN-negative patients who did not undergo groin lymphadenectomy showed no evidence of disease after treatment. On MRI, the long and short diameters of the inguinal node were significantly longer in metastasis-positive cases, compared with negative cases, in 25 patients whose nodes were evaluated pathologically (long diameter, 12.8 mm vs. 8.8 mm, p=0.025; short diameter, 9.2 mm vs. 6.7 mm, p=0.041). The threshold of >10.0 mm for the long axis gave a sensitivity, specificity, positive predictive value, and negative predictive value of 87.5%, 70.6%, 58.3%, and 92.3%, respectively, using a binary classification test. Decision tree analysis revealed a sensitivity, specificity, and accuracy of 87.5%, 70.6%, and 76.0%, respectively, with the threshold of >10.0 mm for the long axis on MRI. The criteria of >10.0 mm for the long axis on MRI predicted an advanced stage and poorer prognosis using a validation set of 15 cases (p=0.028).

CONCLUSION

Minimally invasive surgery after preoperative evaluation on MRI and SLN biopsy is a feasible strategy for patients with vulvar cancer.