Intraoperative identification of canine hepatocellular carcinoma with indocyanine green fluorescent imaging

Augmenting Laparoscopic Surgery with Fluorescence Imaging

Minimally invasive endoscopic surgery is growing in veterinary medicine, in large part, due to the advantages associated with reduced pain, potential for decreased complications, and increased visualization of structures through magnification and illumination. With advancing technologies, we can now improve upon natural "white light" endoscopy with fluorescence-guided imaging. Near-infrared (NIR) cameras allow for real-time, high-definition visualization of vessels, anatomic structures, and perfusion. New uses of NIR technologies during laparoscopy are continuing to grow for vascular, lymphatic, and oncologic-related techniques. Limitations exist, and future efforts need to determine optimal dosing, tissue-specific fluorophores, and veterinary-specific techniques.

Impact of Surgical Lights on the Performance of Fluorescence-Guided Surgery Systems: A Pilot Study

Fluorescence-guided surgery can aid in the intraoperative visualization of target tissues, with promising applications in human and veterinary surgical oncology. The aim of this study was to evaluate the performances of two fluoresce camera systems, IC-Flow^TM and Visionsense^TM VS3 Iridum, for the detection of two non-targeted (ICG and IRDye-800) and two targeted fluorophores (Angiostamp^TM and FAP-Cyan) under different room light conditions, including ambient light, new generation LED, and halogen artificial light sources, which are commonly used in operating theaters. Six dilutions of the fluorophores were imaged in phantom kits using the two camera systems. The limit of detection (LOD) and mean signal-to-background ratio (mSBR) were determined. The highest values of mSBR and a lower LOD were obtained in dark conditions for both systems. Under room lights, the capabilities decreased, but the mSBR remained greater than 3 (=clearly detectable signal). LOD and mSBR worsened under surgical lights for both camera systems, with a greater impact from halogen bulbs on Visionsense^TM VS3 Iridium and of the LED lights on IC-Flow due to a contribution of these lights in the near-infrared spectrum. When considering implementing FGS into the clinical routine, surgeons should cautiously evaluate the spectral contribution of the lights in the operating theater.

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

Objectives

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

Methods

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

Results

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

Conclusions

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

Performance of two clinical fluorescence imaging systems with different targeted and non-targeted near-infrared fluorophores: a cadaveric explorative study

Introduction

Near-infrared (NIR) fluorescence-guided surgery is increasingly utilized in humans and pets. As clinical imaging systems are optimized for Indocyanine green (ICG) detection, the usage of targeted dyes necessitates the validation of these systems for each dye. We investigated the impact of skin pigmentation and tissue overlay on the sensitivity of two NIR cameras (IC-Flow^TM, Visionsense^TM VS3 Iridum) for the detection of non-targeted (ICG, IRDye800) and targeted (Angiostamp^TM, FAP-Cyan) NIR fluorophores in an ex vivo big animal model.

Methods

We quantitatively measured the limit of detection (LOD) and signal-to-background ratio (SBR) and implemented a semi-quantitative visual score to account for subjective interpretation of images by the surgeon.

Results

Visionsense^TM VS3 Iridum outperformed IC-Flow^TM in terms of LOD and SBR for the detection of all dyes except FAP-Cyan. Median SBR was negatively affected by skin pigmentation and tissue overlay with both camera systems. Level of agreement between quantitative and semi-quantitative visual score and interobserver agreement were better with Visionsense^TM VS3 Iridum.

Conclusion

The overlay of different tissue types and skin pigmentation may negatively affect the ability of the two tested camera systems to identify nanomolar concentrations of targeted-fluorescent dyes and should be considered when planning surgical applications.

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

BACKGROUND

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

RESULTS

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

CONCLUSION

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

The use of near infrared fluorescence imaging with indocyanine green for vascular visualization in caudal auricular flaps in two cats

OBJECTIVES

To describe the use of near infrared fluorescence (NIRF) imaging with indocyanine green (ICG) for vascular visualization in two caudal auricular axial pattern flaps (APF).

ANIMALS

Two client-owned cats with upper eyelid masses.

STUDY DESIGN

Clinical case report.

METHODS

Wide surgical excision with enucleation was performed by using a caudal auricular APF for closure. Flap margins and perforating artery location were approximated with anatomical landmarks. The caudal auricular artery origin was then visualized percutaneously by using an exoscope with NIRF camera and light source after a single 2.5-mg dose of IV ICG. Margins were adjusted as required. The flaps were routinely elevated with continued intraoperative visualization of the artery and rotated to complete closure.

RESULTS

After IV ICG administration, fluorescence was initially visualized after 15 to 18 seconds and remained visible for up to 26 minutes. The achieved visualization led to flap margin adjustments in cat 1. Both cats recovered with minimal flap congestion, excellent hair regrowth, and no long-term complications (>186 days). Cat 1 experienced 100% flap survival. Cat 2 experienced 10% partial thickness flap necrosis, but revision was not required, and the flap was healed at recheck 85 days postoperatively.

CONCLUSION

The use of ICG for APF vessel visualization prior to and during flap elevation resulted in transcutaneous visualization of the perforating vessel and improved awareness of vessel location intraoperatively. These two cats experienced excellent flap survival without major complications. This report highlights the potential benefits of ICG NIRF in APF for animals undergoing reconstructive surgery.

Identification of intra-abdominal lymphatics in canine carcasses by laparoscopic fluorescence lymphography with intradermal and intrapopliteal ICG administration

Objective

To evaluate the feasibility of laparoscopic fluorescence lymphography (LFL) using indocyanine green (ICG) via intradermal (ID) or intrapopliteal (IPP) administration in an ex vivo canine model.

Methods

Six thawed adult male dog carcasses were placed in the Trendelenburg position after placing three surgical ports in triangulation. ICG (0.5 mg/ml; 0.05 mg/kg) was administered to five of the carcasses (one carcass was a pilot) via ID in the left torso and IPP (right position, by surgical access) to stain the lymphatic pathway and medial iliac lymph node (MILN). Fluorescence quality, staining time, structures stained, and lymph node histopathology were assessed. Thoracic duct staining was also evaluated.

Results

ID administration showed staining of parts of the lymphatic pathway of the iliosacral lymph center in all cases using a single dose of ICG, with left MILN visualization in four carcasses. IPP administration showed staining of the right MILN in all cases, using a single dose in four carcasses. ICG reached the thoracic duct in one case. The two administration routes showed similar results in terms of required ICG volume, staining time, and visualization quality, although IPP was more effective in staining the MILN.

Conclusions

This study confirms the feasibility of staining the iliosacral lymph center (mainly the MILNs) by LFL in thawed dog carcasses via ID or IPP administration of ICG. However, the IPP route showed greater effectiveness in staining the MILN.

Contrast-Enhanced Multispectral Photoacoustic Imaging for Irregular Hepatectomy Navigation: A Pilot Study

Irregular hepatectomy plays a prominent role in the treatment of small hepatocellular carcinoma (HCC) patients with severe cirrhosis and localized liver metastasis. In clinical practices, intraoperative tumor boundaries delineation facilitates to accomplish tumor resection with negative margin, remarkably decreasing the recurrence rates. Currently, ultrasound (US) and ICG fluorescence-guided surgery has been used for intraoperative navigation in irregular hepatectomy, but insufficient specificity results in a limited prevalence. Inspired by the high resolution of photoacoustic (PA) imaging and established clinical efficacy of ¹⁸F-Alfatide that is specific for integrin α_vβ₃-overexpressed tumors, we herein developed a fluorescent analogue IR820-E[c(RGDfK)]₂, and a proof-of-concept intraoperative multispectral PA imaging navigation for precise irregular hepatectomy using hand-held PA/US imaging system. An integrin α_vβ₃-targeted fluorescent contrast agent IR820-E[c(RGDfK)]₂ was designed, synthesized, and characterized. In vitro studies were performed to determine optical and PA properties, affinity and specificity and biocompatibility. Multispectral PA imaging, the optimal imaging time point and contrast, multispectral PA imaging-guided irregular hepatectomy, pharmacokinetics, and safety profile were evaluated in subcutaneous and orthotopic HCC tumor models. Ex vivo macroscopic three-dimensions (3D) PA imaging with IR820-E[c(RGDfK)]₂ staining was also performed in surgical biospecimens from patients with HCC. IR820-E[c(RGDfK)]₂ has a simple synthetic method at gram scale, high affinity, and specificity for integrin α_vβ₃, excellent pharmacokinetic and safety profile can effectively differentiate tumor from normal liver tissues in animal models and surgical biospecimens from HCC patients. Preoperative tumor localization, intraoperative tumor boundaries delineation, and tumor excision, and postoperative negative margin assessment were successfully achieved during irregular hepatectomy. This initial attempt allows one to preoperatively detect tumor lesions, intraoperatively delineate tumor boundaries and guide tumor resection, and postoperatively evaluate tumor margin status during irregular hepatectomy. IR820-E[c(RGDfK)]₂ has the potential to be an investigational new drug for clinical use in multispectral photoacoustic imaging-guided irregular hepatectomy.

Fluorescence-guided surgery using indocyanine green in dogs with superficial solid tumours

BACKGROUND

Near-infrared fluorescence (NIRF) imaging is a relatively novel technique that can aid surgeons during intraoperative tumour identification.

METHODS

Nine canine oncology patients (five mammary gland tumours, three mast cell tumours and one melanoma) received intravenous indocyanine green (ICG). After 24 hours, tumours were resected and fluorescence intensities of tumours and surroundings were evaluated. Additional wound bed tissue was resected if residual fluorescence was present after tumour resection. Ex vivo, fluorescence-guided dissection was performed to separate tumour from surrounding tissue.

RESULTS

Intraoperative NIRF-guided tumour delineation was feasible in four out of nine dogs. Wound bed imaging after tumour removal identified nine additional fluorescent lesions, of which four contained tumour tissue. One of these four true positive in vivo lesions was missed by standard-of-care inspection. Ex vivo fluorescence-guided tumour dissection showed a sensitivity of 72 per cent and a specificity of 80 per cent in discriminating between tumour and surrounding tissue.

CONCLUSION

The value of ICG for intraoperative tumour delineation seems more limited than originally thought. Although NIRF imaging using ICG did identify remaining tumour tissue in the wound bed, a high false positive rate was also observed.

Advances and perspectives in near-infrared fluorescent organic probes for surgical oncology

Surgical resection of solid tumors is currently the most efficient and preferred therapeutic strategy for treating cancer. Despite significant medical, technical, and scientific advances, the complete treatment of this lethal disease is still a challenging task. New imaging techniques and contrast agents are urgently needed to improve cytoreductive surgery and patient outcomes. Tumor-targeted probes are valuable for guiding a surgical resection of tumor from subjective judgments to visual inspection. Near-infrared (NIR) fluorescent imaging is a promising technology in preclinical and clinical tumor diagnosis and therapy. The rapid development in NIR fluorophores with improved optical properties, targeting strategies, and imaging devices has brought about prospective study of novel NIR nanomaterials for intraoperative tumor detection. In this review, we summarize the recent development in NIR-emitting organic fluorophores and cancer-targeting strategies that specifically target and accumulate in tumors for the molecular imaging of cancerous cells. We believe this technique utilizing new fluorescent probes with an intraoperative optical imaging capacity could provide a more sensitive and accurate method for cancer resection guidance, thereby resulting in better surgical outcomes. This article is categorized under: Diagnostic Tools > in vivo Nanodiagnostics and Imaging Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

Gamma linolenic acid regulates PHD2 mediated hypoxia and mitochondrial apoptosis in DEN induced hepatocellular carcinoma

Introduction

Hepatocellular carcinoma (HCC) is one of the known major health problems across the globe, and is sixth ranked among all cancer, due to its high mortality rate. Polyunsaturated fatty acids (PUFAs) play an important role in the formation of a cell membrane, along with the fluidity of the membrane and proteins. Gamma linolenic acid (GLA) is member of the ω-6 family of PUFAs and converts into the arachidonic acid via a series of elongation and desaturation reactions. The aim of the current investigation was to scrutinize the effect of GLA on mitochondrial mediated apoptosis and anti-inflammatory pathway against diethylnitrosamine (DEN) induced HCC.

Materials and methods

Chemical carcinogenesis in Wistar rats was introduced by an intra-peritoneal dose of DEN (200 mg/kg). The rats received the various doses of GLA for 22 weeks. The progressions of serum biomarkers and histopathology components of hepatic tissue were used to access the prophylactic effects. The antioxidant parameters, cancer preventive agent status, and apoptosis mechanism were reviewed to scrutinize the possible mechanism.

Results

Dose-dependent treatment of GLA significantly (P<−0.001) modulated the hepatic nodules, hepatic, body weight, antioxidant, and non-hepatic parameters. Curiously, the Real-time polymerase chain reaction (RT-PCR) and immunoblotting showed the GLA altered reduced the hypoxic microenvironment, mitochondrial mediated death apoptosis, and anti-inflammsatory pathways.

Conclusion

On the basis of the above results, we can conclude that the GLA exhibited a chemo-protective effect against DEN induced HCC that might be due to the altered hypoxic microenvironment, mitochondrial mediated death apoptosis, and anti-inflammatory pathway, respectively.

Fluorescent contrast agents for tumor surgery

Cancer is a leading cause of cases of mortality worldwide. The most effective method to cure solid tumors is surgery. Every year, >50% of cancer patients receive surgery to remove solid tumors. Surgery may increase the cure rate of most solid tumors by 4–11 fold. Surgery has many challenges, including identifying small lesions, locating metastases and confirming complete tumor removal. Fluorescence guidance describes a new approach to improve surgical accuracy. Near-infrared fluorescence imaging allows for real-time early diagnosis and intraoperative imaging of lesion tissue. The results of previous preclinical studies in the field of near-infrared fluorescence imaging are promising. This review provides examples introducing the three kinds of fluorescent dyes: The passive fluorescent dye indocyanine green, which has been approved by the Food and Drug Administration for clinical use in the USA, the fluorescent prodrug 5-aminolevulinic acid, a porphyrin precursor in the heme synthesis, and biomarker-targeted fluorescent dyes, which allow conjugation to different target sites.

Surgical management of primary, metastatic and recurrent anal sac adenocarcinoma in the dog: 52 cases

OBJECTIVES

To report the outcomes and complications of a cohort of dogs with primary and recurrent anal sac adenocarcinoma managed with surgery as the first-line treatment. To report the use of lymph node cytology for identification of metastatic disease.

METHODS

Retrospective review of case records of a single referral centre population of dogs diagnosed with anal sac adenocarcinoma.

RESULTS

Fifty-two clinical cases were identified. Altered ultrasonographic appearance of lymph nodes was highly consistent with metastatic disease as assessed by cytology and histopathology. Seven of 58 (12%) perineal surgeries had reported minor complications and seven (12%) others required further surgical intervention. Minor controllable intraoperative bleeding was the only complication noted associated with lymph node extirpation in two of 39 (5%) metastectomy procedures. Six dogs (12%) suffered local recurrence and 22 (42%) developed subsequent or recurrent nodal metastatic disease. From the time of detection of disease recurrence, median additional survival associated with a second surgical intervention was 283 days.

CLINICAL SIGNIFICANCE

Coeliotomy for lymph node metastatectomy in dogs with adenocarcinoma of the anal sac has low morbidity and should be considered in patients presenting with evidence of regional metastatic disease both at initial presentation and with recurrent disease.

Combination of Fluorescence-Guided Surgery With Photodynamic Therapy for the Treatment of Cancer

Specific visualization of body parts is needed during surgery. Fluorescence-guided surgery (FGS) uses a fluorescence contrast agent for in vivo tumor imaging to detect and identify both malignant and normal tissues. There are several advantages and clinical benefits of FGS over other conventional medical imaging modalities, such as its safety, effectiveness, and suitability for real-time imaging in the operating room. Recent advancements in contrast agents and intraoperative fluorescence imaging devices have led to a greater potential for intraoperative fluorescence imaging in clinical applications. Photodynamic therapy (PDT) is an alternative modality to treat tumors, which uses a light-sensitive drug (photosensitizers) and special light to destroy the targeted tissues. In this review, we discuss the fluorescent contrast agents, some newly developed imaging devices, and the successful clinical application of FGS. Additionally, we present the combined strategy of FGS with PDT to further improve the therapeutic effect for patients with cancer. Taken together, this review provides a unique perspective and summarization of FGS.

Imaging of Liver Tumors Using Surface-Enhanced Raman Scattering Nanoparticles

Complete surgical resection is the ideal first-line treatment for most liver malignancies. This goal would be facilitated by an intraoperative imaging method that enables more precise visualization of tumor margins and detection of otherwise invisible microscopic lesions. To this end, we synthesized silica-encapsulated surface-enhanced Raman scattering (SERS) nanoparticles (NPs) that act as a molecular imaging agent for liver malignancies. We hypothesized that, after intravenous administration, SERS NPs would avidly home to healthy liver tissue but not to intrahepatic malignancies. We tested these SERS NPs in genetically engineered mouse models of hepatocellular carcinoma and histiocytic sarcoma. After intravenous injection, liver tumors in both models were readily identifiable with Raman imaging. In addition, Raman imaging using SERS NPs enabled detection of microscopic lesions in liver and spleen. We compared the performance of SERS NPs to fluorescence imaging using indocyanine green (ICG). We found that SERS NPs delineate tumors more accurately and are less susceptible to photobleaching. Given the known advantages of SERS imaging, namely, high sensitivity and specific spectroscopic detection, these findings hold promise for improved resection of liver cancer.

Evaluation of intraoperative fluorescence imaging-guided surgery in cancer-bearing dogs: a prospective proof-of-concept phase II study in 9 cases

The objective was to prospectively evaluate the application of intraoperative fluorescence imaging (IOFI) in the surgical excision of malignant masses in dogs, using a novel lipid nanoparticle contrast agent. Dogs presenting with spontaneous soft-tissue sarcoma or subcutaneous tumors were prospectively enrolled. Clinical staging and whole-body computed tomography (CT) were performed. All the dogs received an intravenous injection of dye-loaded lipid nanoparticles, LipImage 815. Wide or radical resection was realized after CT examination. Real-time IOFI was performed before skin incision and after tumor excision. In cases of radical resection, the lymph nodes (LNs) were imaged. The margin/healthy tissues fluorescence ratio or LN/healthy tissues fluorescence ratio was measured and compared with the histologic margins or LN status. Nine dogs were included. Limb amputation was performed in 3 dogs, and wide resection in 6. No adverse effect was noted. Fluorescence was observed in all 9 of the tumors. The margins were clean in 5 of 6 dogs after wide surgical resection, and the margin/healthy tissues fluorescence ratio was close to 1.0 in all these dogs. Infiltrated margins were observed in 1 case, with a margin/healthy tissues fluorescence ratio of 3.2. Metastasis was confirmed in 2 of 3 LNs, associated with LN/healthy tissues fluorescence ratios of 2.1 and 4.2, whereas nonmetastatic LN was associated with a ratio of 1.0. LipImage 815 used as a contrast agent during IOFI seemed to allow for good discrimination between tumoral and healthy tissues. Future studies are scheduled to evaluate the sensitivity and specificity of IOFI using LipImage 815 as a tracer.