Combined Use of Contrast-Enhanced Intraoperative Ultrasonography and a Fluorescence Navigation System for Identifying Hepatic Metastases

Diagnostic Accuracy of Sonazoid-Enhanced Ultrasonography for Detection of Liver Metastasis

PURPOSE

To evaluate the potential clinical role and reliability of Sonazoid-enhanced ultrasound (SEUS) as a diagnostic tool for liver metastatic lesions.

METHODS

An extensive literature search was conducted across five electronic databases, PubMed, Scopus, Embase, Cochrane Library, and Web of Science, from their inception up to January 2024 to identify all studies evaluating the use of Sonazoid-enhanced ultrasonography for detecting hepatic metastases. A meta-analysis was performed to assess diagnostic accuracy using the Meta-DiSc 2.0 software.

RESULTS

A total of 31 studies were included, 16 of which were eligible for meta-analysis and diagnostic test accuracy evaluation. A total of 13 studies in the meta-analysis evaluated the diagnostic accuracy of contrast-enhanced ultrasound (CEUS) for 1347 metastatic and 1565 non-metastatic liver lesions. The pooled sensitivity and specificity for CEUS were 0.88 (95% CI: 0.82-0.92) and 0.92 (95% CI: 0.84-0.96), respectively. The combined positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 11.89 (95% CI: 5.42-26.09), 0.12 (95% CI:0.08-0.19), and 91.99 (95% CI: 32.15-263.17), respectively. Additionally, four studies of the meta-analysis assessed the diagnostic performance of contrast-enhanced intraoperative sonography (CE-IOUS) in detecting 664 metastatic and 246 non-metastatic liver lesions. The pooled sensitivity and specificity for CE-IOUS were 0.93 (95% CI: 0.82-0.97) and 0.84 (95% CI: 0.65-0.93), respectively. The aggregated positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were calculated as 5.95 (95% CI: 2.32-15.25), 0.07 (95% CI: 0.02-0.24), and 77.68 (95% CI: 10.33-583.86), respectively.

CONCLUSIONS

CE-IOUS and CEUS are reliable approaches for diagnosing liver metastatic lesions. CE-IOUS, in particular, exhibits higher accuracy in identifying liver metastatic lesions, indicating its potential effectiveness in clinical practice.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Synthesis, Preclinical Evaluation, and First-in-Human Assessment of ICG-PSMA-D5: A PSMA-Targeted Probe for Fluorescence-Guided Surgery of Prostate Cancer

Precise surgical resection of prostate cancer (PCa) is a significant clinical challenge due to the impact of positive surgical margins on postoperative outcomes. Fluorescence-guided surgery (FGS) enables real-time tumor visualization using fluorescent probes. In this study, we synthesized and evaluated an indocyanine green (ICG)-based PSMA-targeted near-infrared probe, ICG-PSMA-D5, for intraoperative imaging of PCa lesions. Spectroscopic analysis revealed that ICG-PSMA-D5 retained the optical properties of ICG while improving solubility in PBS due to additional carboxyl groups. In vitro assays demonstrated high binding affinity (Ki = 0.39 nM) and minimal cytotoxicity. In vivo studies in tumor-bearing mice showed strong tumor targeting, extended retention at tumor site, and favorable biodistribution, with significant tumor-to-background ratios. The first-in-human study in a patient with localized PCa indicated the probe's potential for real-time, radiation-free surgical guidance. Overall, ICG-PSMA-D5 displayed excellent performance in tumor detection and margin delineation, making it a promising candidate for intraoperative FGS in PCa.

Fluorescence and tracers in surgery: the coming future

The revolution that we are seeing in the world of surgery will determine the way we understand surgical approaches in coming years. Since the implementation of minimally invasive surgery, innovations have constantly been developed to allow the laparoscopic approach to go further and be applied to more and more procedures. In recent years, we have been in the middle of another revolutionary era, with robotic surgery, the application of artificial intelligence and image-guided surgery. The latter includes 3D reconstructions for surgical planning, virtual reality, holograms or tracer-guided surgery, where ICG-guided fluorescence has provided a different perspective on surgery. ICG has been used to identify anatomical structures, assess tissue perfusion, and identify tumors or tumor lymphatic drainage. But the most important thing is that this technology has come hand in hand with the potential to develop other types of tracers that will facilitate the identification of tumor cells and ureters, as well as different light beams to identify anatomical structures. These will lead to other types of systems to assess tissue perfusion without the use of tracers, such as hyperspectral imaging. Combined with the upcoming introduction of ICG quantification, these developments represent a real revolution in the surgical world. With the imminent implementation of these technological advances, a review of their clinical application in general surgery is timely, and this review serves that aim.

Laparoscopic versus open in right posterior sectionectomy: a systematic review and meta-analysis

BACKGROUND

Laparoscopic liver resection (LLR) is now widely adopted for the treatment of liver tumors due to its minimally invasive advantages. However, multicenter, large-sample population-based laparoscopic right posterior sectionectomy (LRPS) has rarely been reported. We aimed to assess the advantages and drawbacks of right posterior sectionectomy compared with laparoscopic and open surgery by meta-analysis.

METHODS

Relevant literature was searched using the PubMed, Embase, Cochrane, Ovid Medline, and Web of Science databases up to September 12, 2021. Quality assessment was performed based on a modified version of the Newcastle-Ottawa Scale (NOS). The data were analyzed by Review Manager 5.3. The data were calculated by odds ratio (OR) or mean difference (MD) with 95% confidence intervals (CI) for fixed-effects and random-effects models.

RESULTS

The meta-analysis included seven studies involving 739 patients. Compared with open right posterior sectionectomy (ORPS), the LRPS group had lower intraoperative blood loss (MD - 135.45; 95%CI - 170.61 to - 100.30; P < 0.00001) and shorter postoperative hospital stays (MD - 2.17; 95% CI - 3.03 to - 1.31; P < 0.00001). However, there were no statistically significant differences between LRPS and ORPS regarding operative time (MD 44.97; P = 0.11), pedicle clamping (OR 0.65; P = 0.44), clamping time (MD 2.72; P = 0.31), transfusion rate (OR 1.95; P = 0.25), tumor size (MD - 0.16; P = 0.13), resection margin (MD 0.08; P = 0.63), R0 resection (OR 1.49; P = 0.35), recurrence rate (OR 2.06; P = 0.20), 5-year overall survival (OR 1.44; P = 0.45), and 5-year disease-free survival (OR 1.07; P = 0.88). Furthermore, no significant difference was observed in terms of postoperative complications (P = 0.08), bile leakage (P = 0.60), ascites (P = 0.08), incisional infection (P = 0.09), postoperative bleeding (P = 0.56), and pleural effusion (P = 0.77).

CONCLUSIONS

LRPS has an advantage in the length of hospital stay and blood loss. LRPS is a very useful technology and feasible choice in patients with the right posterior hepatic lobe tumor.

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

Objective

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

Background

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

Methods

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

Results

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

Conclusion

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

Indocyanine green (ICG) fluorescence guide for the use and indications in general surgery: recommendations based on the descriptive review of the literature and the analysis of experience

Indocyanine Green is a fluorescent substance visible in near-infrared light. It is useful for the identification of anatomical structures (biliary tract, ureters, parathyroid, thoracic duct), the tissues vascularization (anastomosis in colorectal, esophageal, gastric, bariatric surgery, for plasties and flaps in abdominal wall surgery, liver resection, in strangulated hernias and in intestinal ischemia), for tumor identification (liver, pancreas, adrenal glands, implants of peritoneal carcinomatosis, retroperitoneal tumors and lymphomas) and sentinel node identification and lymphatic mapping in malignant tumors (stomach, breast, colon, rectum, esophagus and skin cancer). The evidence is very encouraging, although standardization of its use and randomized studies with higher number of patients are required to obtain definitive conclusions on its use in general surgery. The aim of this literature review is to provide a guide for the use of ICG fluorescence in general surgery procedures.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Improved sensitivity and positive predictive value of contrast-enhanced intraoperative ultrasound in colorectal cancer liver metastasis: a systematic review and meta-analysis

BACKGROUND

Surgery is an effective treatment for improving the survival rate of patients with colorectal cancer liver metastases (CRLM). However, accurately determining the resection margin of liver lesions during surgery remains challenging. Therefore, this study aimed to evaluate the sensitivity and predictive value of intraoperative contrast-enhanced ultrasound (CE-IOUS) in CRLM patients undergoing surgery.

METHODS

We performed a literature search of the PubMed, Cochrane Central Register of Controlled Trials, Embase, Web of Science, China National Knowledge Infrastructure (CNKI), Wanfang, and Weipu databases using the following search terms: metastatic liver cancer, colorectal cancer, sensitivity, contrast-enhanced intraoperative ultrasound, CE-IOUS, colorectal liver metastases, and CRLM. The search period was set from the date of establishment of the database to September 2021. Quality assessment of diagnostic accuracy studies 2 (QUADAS-2) recommended by the Cochrane Collaboration was used to assess the methodological quality of the included studies, and network meta-analysis was performed using Stata 15.0 software.

RESULTS

A total of 10 articles met the inclusion criteria. The meta-analysis results showed that the overall sensitivity and specificity of CE-IOUS were 0.96 [95% confidence interval (CI), 0.95-0.97] and 0.75 (95% CI, 0.70-0.80), respectively. The overall sensitivity and specificity of IOUS were 0.84 (95% CI, 0.82-0.86) and 0.82 (95% CI, 0.77-0.87), respectively. The area under the summary receiving operating characteristic (SROC) curves (AUCs) of CE-IOUS and IOUS were 0.9753 and 0.8590, respectively. The odds ratio (OR) and 95% CI of CE-IOUS changed the surgical margin were 0.205 and 0.071-0.465, P=0.000, the difference was statistically significant.

DISCUSSION

Based on the results of this meta-analysis, CE-IOUS improved the sensitivity and predictive value of CRLM detection compared with IOUS, and is more suitable for intraoperative planning of surgical margins. At present, it is the most sensitive imaging method available, and is recommended for use during liver resection to provide doctors with more reliable information during surgery.

A meta-analysis evaluating contrast-enhanced intraoperative ultrasound (CE-IOUS) in the context of surgery for colorectal liver metastases

BACKGROUND

This study aimed to assess the outcomes of contrast-enhanced intraoperative ultrasound (CE-IOUS) for patients with colorectal liver metastases (CRLMs) undergoing surgery.

METHOD

A thorough literature search was performed in PubMed, Scopus, and Cochrane databases, in accordance with the PRISMA guidelines. The Odds Ratio, Weighted Mean Difference, and 95% Confidence Interval were evaluated, by means of Random-Effects model.

RESULTS

Eleven articles met the inclusion criteria and incorporated 497 patients. The present study shows that CE-IOUS is associated with higher sensitivity and accuracy compared with multidetector computed tomography (MDCT), magnetic resonance imaging (MRI), and intraoperative ultrasound (IOUS) in identifying CRLMs (p < 0.05). The positive predictive value was similar among the different modalities. Furthermore, new CRLMs were identified by CE-IOUS, thus affecting the surgical plan in 128 patients (51.8% of the patients with new CRLMs). Moreover, 91 patients (71%) underwent a more extensive hepatectomy and 15 patients (11.7%) were considered non-operable. Two alternative contrast agents, Sonazoid and Sonovue, were employed with similar sensitivity (p > 0.05).

CONCLUSION

These outcomes suggest the superiority of the CE-IOUS over MDCT, MRI, and IOUS for the staging of patients with CRLMs undergoing surgery. However, they should be treated with caution given the small number of the included studies.

Application of Near-Infrared Fluorescence Imaging Technology in Liver Cancer Surgery

Background. Hepatocellular carcinoma, among the most common malignant digestive system tumorsworldwide, is most effectively treated with precise surgical resection. Near-infrared fluorescence imaging technology is being increasingly used clinically and has achieved great initial results in the navigation of liver cancer surgery. Methods. This review describes the application of indocyanine green fluorescence (ICG) imaging technology with near-infrared window I in the navigation of liver cancer surgery, explores novel fluorescent probes and near-infrared window II fluorescence imaging technology, and discusses the development status of the 2 emerging tools. Results. ICG fluorescence imaging technology can precisely localize the tumor, reveal the boundary of liver cancer or liver segment, and identify the bile leakage. The novel fluorescent probe is more targeted than ICG, which makes the detection of cancer more accurate. Near-infrared window II fluorescence imaging technology can lead to outstanding gains in deeper detection, higher resolution, and fidelity. But, due to the shortcomings of machine and probe, it is not widely used in clinical. Conclusion. Near-infrared fluorescence imaging has great development potential. With the advent of precision medicine and the progress of various biotechnology studies, fluorescence imaging technology will be better developed and applied in the diagnosis, surgical navigation, and treatment of liver cancer.

Fluorescence-guided hepatobiliary surgery with long and short wavelength fluorophores

Importance

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

Objective

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

Evidence Review

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

Findings

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

Conclusions and Relevance for Reviews

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

Efficacy and safety of laparoscopic hepatectomy for hepatocellular carcinoma comorbid with cirrhosis

Introduction

Laparoscopic hepatectomy (LH) is very difficult to perform in patients with cirrhosis because of the haemorrhagic and fibrotic nature of the liver, although there are various advantages to laparoscopic surgery.

Aim

To investigate the surgical outcomes, and efficacy and safety of LH versus open hepatectomy (OH) for hepatocellular carcinoma (HCC) resection.

Material and methods

A total of 112 patients with cirrhosis, who underwent hepatectomy, were analysed retrospectively. We investigated the safety and efficacy of LH for HCC with cirrhosis. Student's t and χ² tests, Mann-Whitney's U test, Wilcoxon's signed-rank test, and Fisher's exact test were used in the statistical analysis.

Results

Seventy-one patients underwent LH, and 41 underwent OH. The conversion rate from LH to OH was 12.7%. After propensity score matching, the estimated blood loss was significantly lower in the LH group than in the OH group (25 vs. 310 ml; p < 0.001), and there was a significant difference between the groups in the operative time (p = 0.091). The LH group had complication rates of 3.6% and 0% for refractory ascites and pleural effusion, respectively, while those were 17.9% and 10.7%, respectively, in the OH group (p = 0.019 and p = 0.005, respectively). The LH group had no mortality, whereas the OH group had a mortality rate of 10.7% (p = 0.038). The postoperative length of stay was significantly longer in the LH group than in the OH group (9 days vs. 14 days) (p = 0.002).

Conclusions

LH can be performed safely for HCC with cirrhosis. More favourable results are achieved with LH than with OH in terms of surgical outcomes.

Comparative analysis of the safety and feasibility of laparoscopic versus open caudate lobe resection

PURPOSE

Laparoscopic hepatectomy has been used widely in liver disease due to its advantages as a minimally invasive surgery. However, laparoscopic caudate lobe resection (LCLR) has been reported rarely. We aimed to investigate the safety and feasibility of LCLR by comparing it with open liver surgery.

METHODS

A retrospective study was performed including all patients who underwent LCLR and open caudate lobe resection (OCLR) between January 2015 and August 2019. Twenty-two patients were involved in this study and divided into LCLR (n = 10) and OCLR (n = 12) groups based on preoperative imaging, tumor characteristics, and blood and liver function test. Patient demographic data and intraoperative and postoperative outcomes were compared between the two groups.

RESULTS

There were no significant inter-group differences between gender, age, preoperative liver function, American Society of Anesthesiologists (ASA) grade, and comorbidities (P > 0.05). The LCLR showed significantly less blood loss (50 vs. 300 ml, respectively; P = 0.004), shorter length of hospital stay (15 vs. 16 days, respectively; P = 0.034), and shorter operative time (216.50 vs. 372.78 min, respectively; P = 0.012) than OCLR, but hospital expenses (5.02 vs. 6.50 WanRMB, respectively; P = 0.208) showed no statistical difference between groups. There was no statistical difference in postoperative bile leakage (P = 0.54) and wound infection (P = 0.54) between LCLR and OCLR. Neither LCLR nor OCLR resulted in bleeding or liver failure after operation. There were no deaths.

CONCLUSION

LCLR is a very useful technology, and it is a feasible choice in selected patients with benign and malignant tumors in the caudate lobe.

Short-term Results of Laparoscopic versus Open Liver Resection for Liver Metastasis from Colorectal Cancer: A Comparative Study

Laparoscopic liver resection is currently performed in an increasing number of institutions as a minimally invasive treatment. However, no randomized controlled trials have compared laparoscopic and open liver resections. Twenty-three laparoscopic and 24 open liver resections for colorectal cancer liver metastases (CRCLM) were performed, and these data for both were retrospectively compared in the short-term results. The estimated blood loss was 99 ± 207 mL in the laparoscopic group and 397 ± 381 mL in the open group ( P = 0.0018); blood loss was significantly higher in the open group. There were no differences in the surgical procedure, blood loss, transfusion rate, pathological margins, postoperative complications, 30-day mortality, duration of intravenous drip, or hospital stay. On postoperative courses, the values of total bilirubin, white blood cell count, and C-reactive protein were significantly lower in the laparoscopic group. The data of the present series suggest the lesser invasiveness and safety of laparoscopic liver resection even for patients with CRCLM, and they showed that postoperative laboratory tests were better after laparoscopy than after the traditional open approach with better short-term results. Tumor diameter less than 5 cm appears to be the appropriate indication for laparoscopic liver resection for CRCLM.

Current status of laparoscopic liver resection for the management of colorectal liver metastases

Colorectal cancer (CRC) is one of the most prevalent malignancies worldwide. The commonest site of spread is the liver, with up to 40% of patients developing colorectal liver metastasis (CLRM) during the course of their lifetime. Significant advances in surgical techniques, as well as breakthroughs in chemotherapy and biologic agents, have resulted in dramatic improvements in prognosis. A multimodal approach comprising of liver resection coupled with systemic therapy offers these patients the best chance of cure. The arrival of laparoscopic liver resection (LLR) within the last 3 decades has added a whole new dimension to the management of this condition. Today, CLRM is one of the most frequent indications for LLR globally. Meta-analyses of retrospective studies and two randomized trials have demonstrated superior short-term outcomes following LLR, with no differences in mortality rates. Oncologically, R0 resection rates are comparable to the open approach, while overall and disease-free survival rates are also similar. As surgeons gain confidence, boundaries are pushed even further. High-volume centers have published their early experiences with complex LLR of recurrent CLRM as well as totally laparoscopic synchronous resection of CRC and liver metastases, with very encouraging results. In the presence of extensive bilobar CLRM, two-stage hepatectomy (TSH) and associating liver partition with portal vein ligation (ALPPS) may be adopted to augment an inadequate future liver remnant to facilitate metastasectomy. Interestingly, the adoption of LLR for these techniques also seem to confer additional benefits. Despite the plethora of advantages, LLR comes with its own unique set of limitations such as a steep learning curve and high cost. The surgical world eagerly awaits the results of prospective trials currently underway in order to further advance the management of this disease.

Application of Fluorescent Dyes in Visceral Surgery: State of the Art and Future Perspectives

Background

Through the improvement and implementation of advanced intraoperative imaging, the indications for intraoperative fluorescence have spread to various fields of visceral surgery. Indocyanine green (ICG)-based fluorescence angiography and the imaging systems using this certain dye are currently the cornerstone of intraoperative, fluorescence-based medical imaging.

Summary

The article focuses on principles and approaches of intraoperative fluorescence in general surgery. The current clinical practice of intraoperative fluorescence and its evidence are described. Emerging new fields of application are put in a perspective. Furthermore, the technique and possible pit-falls in the performance of intraoperative ICG fluorescence angiography are described in this review article.

Key Messages

Overall growing evidence suggests that intraoperative fluorescence imaging delivers valuable additional information to the surgeon, which might help to perform surgery more exactly and reduce perioperative complications. Perfusion assessment can be a helpful tool when performing critical anastomoses. There is evidence from prospective and randomized trials for the benefit of intraoperative ICG fluorescence angiography during esophageal reconstruction, colorectal surgery, and surgery for mesenteric ischemia. Most studies suggest the administration of 2.5-10 mg of ICG. Standardized settings and documentation are essential. The benefit of ICG fluorescence imaging for gastrointestinal sentinel node detection and detection of liver tumors and colorectal metastases of the liver cannot clearly be estimated duo to the small number of prospective studies. Critical points in the use of intraoperative fluorescence imaging remain the low standardization and reproducibility of the results and the associated difficulty in comparing the results of the existing trials. Furthermore, little is known about the influence of hemodynamic parameters on the quantitative assessment of ICG fluorescence during surgery.

Laparoscopic Repeat Hepatectomy with Indocyanine Green Fluorescence Navigation: A Case Report

The indocyanine green (ICG) fluorescence method is reportedly useful for intraoperative visualization of hepatocellular carcinoma and metastatic liver cancer. Herein, we report the use of an ICG fluorescence navigation system for laparoscopic hepatectomy. The patient was a 73-year-old man with a surgical history of two laparotomies for hepatocellular carcinoma resection. During follow-up at our hospital, abdominal computed tomography revealed recurrence of hepatocellular carcinoma in the lateral area of the liver, after which the patient was hospitalized for surgery. His surgical history indicated that adhesions in the abdominal cavity were likely. We scheduled laparoscopic repeat hepatectomy (LRH) with an ICG fluorescence method in which ICG dye was injected intravenously 2 days before surgery. ICG fluorescence was easily detected intraoperatively. The advantages of the present approach are that it induces pneumoperitoneum and, with laparoscopic magnification, enables good visualization of the surgical field for LRH and clear intraoperative identification of the tumor, thus facilitating LRH. Laparoscopic partial resection of the liver (S3) was successfully performed; the operation time was 197 minutes and bleeding volume was 30 mL. Postoperative course was uneventful and he was discharged on postoperative day 10.

Improving the Surgical Effect for Primary Liver Cancer with Intraoperative Fluorescence Navigation Compared with Intraoperative Ultrasound

BACKGROUND This study aimed to compare the application value of intraoperative fluorescence navigation technology (FNT) and intraoperative ultrasound (IOUS) in primary liver cancer surgery. MATERIAL AND METHODS Fifty consecutive patients with primary liver cancer scheduled to receive surgical treatment were divided into FNT group and IOUS group. FNT and IOUS were separately used to guide tumor resection and detect new cancerous lesions in the 2 groups. The complete tumor resection rate (R0) resection rate, length of the tumor distance from cutting edge, the diagnostic efficacy of cancerous nodules and the fluorescence imaging characteristics of different types tumors were recorded. RESULTS The R0 resection rate was 100% (25 out of 25 patients) in the FNT group and 96% (24 out of 25 patients) in the IOUS group. In the FNT group, 1 case (4%, 1 out of 25 patients) had cancer tissue that was less than 1 cm from the cutting edge, compared to 7 cases (28%, 7 out of 25 patients) in the IOUS group (P=0.049), which was a significant difference. In the remaining livers of 50 consecutive patients, FNT found 5 new cancerous nodules with a sensitivity of 71.4%, a specificity of 11.1%, and a false-positive rate of 88.9%; for IOUS the results were 42.9%, 88.9%, 11.1%. The fluorescence imaging characteristics of all well-differentiated hepatocellular carcinomas were tumor tissue imaging, but all other types of tumors were ring imaging around the tumor. CONCLUSIONS FNT can improve the R0 resection rate, ensure a safe distance between tumor and cutting edge and can identify more new cancerous nodules compared to IOUS. Thus, FNT could improve the surgical treatment effect for primary liver cancer and hopefully further improve the prognosis of patients.

Cancer Selective Turn-On Fluorescence Imaging Using a Biopolymeric Nanocarrier

Most nanoparticle-based bioresearch for clinical applications is unable to overcome the clinical barriers of efficacy (e.g., sensitivity and selectivity), safety for human use, and scalability for mass-production processes. Here, we proposed a promising concept of using a biocompatible nanocarrier that delivers natural fluorescent precursors into cancerous cells. The nanocarrier is a biopolymeric nanoparticle that can be easily loaded with fluorescent precursors to form a fluorescent moiety via a biosynthesis pathway. Once delivered into cancerous cells, the nanocarriers are selectively turned on and distinctively fluoresce upon excitation. We, therefore, demonstrated the efficacy of the selective turn-on fluorescence of the nanocarriers in in vitro coculture models and in vivo tumor-bearing models.

Fluorescence Imaging for Minimally Invasive Cancer Surgery

This article demonstrates surgical techniques of intraoperative fluorescence imaging using indocyanine green, focusing on its application in minimally invasive hepatobiliary and pancreatic surgery. In this area, indocyanine green fluorescence imaging has been applied to liver cancer identification, fluorescence cholangiography, delineation of hepatic segments, and fluorescence angiography and perfusion assessment. The development of target-specific fluorophores and advances in imaging technology will allow real-time intraoperative fluorescence imaging to develop into an essential intraoperative navigation tool. This property may contribute to enhancing both accuracy and safety of minimally invasive surgery.

The utility of the subcuticular suture in hepatic resection

Aim of the study

Despite recent technical progress and advances in the perioperative management of liver surgery, postoperative surgical site infection (SSI) is still one of the most common complications that extends hospital stays and increases medical expenses following hepatic surgery.

Material and methods

From 2001 to 2017 a total of 1180 patients who underwent hepatic resection for liver tumours were retrospectively analysed with respect to the predictive factor of superficial incisional SSI, using a propensity score matching by procedure (subcuticular or mattress suture).

Results

The incidence of superficial and deep incisional SSIs was found to be 7.1% (84/1180). By propensity score matching (PSM), 121 of the 577 subcuticular suture group patients could be matched with 121 of the 603 mattress suture group patients. Multivariate analysis demonstrated wound closure technique as the only independent risk factor that correlated significantly with the occurrence of superficial incisional SSIs (p = 0.038). C-reactive protein (CRP) levels on postoperative day 4 were significantly higher in patients with incisional SSIs than in those without (p < 0.001).

Conclusions

Wound closure technique with subcuticular continuous spiral suture using absorbable suture should be considered to minimise the incidence of incisional SSIs. Moreover, wounds should be carefully checked when CRP levels are high on postoperative day 4.

Comparison of Regeneration of Remnant Liver After Hemihepatectomy with or Without the Middle Hepatic Vein

BACKGROUND

There is no consensus about remnant liver regeneration associated with middle hepatic vein (MHV) resecting.

METHODS

Seventy-five patients who underwent hemihepatectomy were retrospectively analysed with respect to remnant liver regeneration. The liver remnant volume (LRV) and each sectional volume were postoperatively measured with multidetector computed tomography at day 7 and months 1, 2, 5, and 12 after the operation.

RESULTS

In right hemihepatectomy cases, the regeneration rate of LRV in the MHV preservation group was significantly higher than that of the MHV resection group at months 5 and 12. In particular, the regeneration rate of remnant segment IV peaked at day 7 and was shrunk after 1 month, and was significant higher in the MHV preservation group. In left hemihepatectomy cases, the regeneration rate of LRV at month 12 was significantly higher in the MHV preservation group. The regeneration rate of the remnant anterior section peaked at 1 month and was shrunk.

CONCLUSION

In this study, the MHV should be preserved or reconstructed whenever possible during hepatic hemihepatectomy. Hepatic regeneration in the MHV perfusion region becomes poor within 7 days to 1 month after surgery (UMIN000023714).

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.

Indocyanine green identification for tumor infiltration or metastasis originating from hepatocellular carcinoma

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The indocyanine green-photodynamic eye (ICG-PDE) system was useful to clearly detect metastasis or tumor thrombus, as well as main tumor, originated from hepatocellular carcinoma and all lesions could be resected.

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This system may be applied to improve determining the location of metastasis or tumor thrombus.

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Tumor thrombus originated from hepatocellular carcinoma (HCC) in the portal vein or inferior vena cava could be well identified by ICG-PDE. The metastasized HCC lesion in an adrenal gland was clearly detected. All lesions could be completely resected.

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ICG-PDE is a useful tool for detecting the precise tumor location even in extrahepatic tumor lesions or tumor thrombus, which is useful for deciding which parts to resect.

Introduction

The indocyanine green-photodynamic eye (ICG-PDE) system is useful to detect small hypervascular liver tumors, hepatocellular carcinoma (HCC), on the liver surface. This system may be also applied to improve determining the location of metastasis or tumor thrombus (TT). We herein report three case reports. ICG was administered preoperatively for functional testing and images of the tumor were observed during hepatectomy using a PDE camera.

Case series

The patient in case 1 exhibited advanced HCC with TT in the portal trunk. The TT in the right portal vein was clearly fluorescent by ICG-PDE and the right portal vein was adequately transected to remove TT. The patient in case 2 exhibited a large HCC in the right liver and the right adrenal gland was simultaneously swollen with enhancement. By confirming the fluorescent spot in the right adrenal gland, the metastasized lesion was completely resected. The patient in case 3 previously underwent central bi-segmentectomy, and lymph node metastasis and TT in the vena cava was observed during one-year follow-up. Although it was difficult to detect the definite margin of these lesions by the outline appearance, both lesions could be clearly observed with strong fluorescence and were completely resected.

Discussion and conclusion

ICG-PDE is a useful tool for detecting the precise tumor location even in extrahepatic tumor lesions, such as metastases or tumor thrombus, which is useful for deciding which parts to resect.

Optical molecular imaging for tumor detection and image-guided surgery

We have witnessed rapid development of fluorescence molecular imaging of solid tumors for cancer diagnosis and image-guided surgery in the past decade. Many biomarkers unique to cancer cells or tumor microenvironment, such as cell surface receptors, hypoxia, secreted proteases and extracellular acidosis have been characterized, and can be used to distinguish cancer from normal tissue. A variety of optical imaging probes have been developed to target these biomarkers to improve tumor contrast over the background tissue. Unlike conventional anatomical and molecular imaging technologies, fluorescent imaging method benefits from its safety, high-spatial resolution and real-time capability, and therefore, has become a highly adoptable imaging method for tumor detection and image-guided surgery in clinics. In this review, we summarize recent progress in 'always-ON' and stimuli-activatable fluorescent imaging probes, and discuss their potentials in tumor detection and image-guided surgery.

Short- and Long-Term Results of Laparoscopic Parenchyma-Sparing Hepatectomy for Small-Sized Hepatocellular Carcinoma: A Comparative Study Using Propensity Score Matching Analysis

The aim of this study was to evaluate the degree of invasiveness and the clinical outcomes of laparoscopic parenchyma-sparing hepatectomy (LPSH) for a maximum hepatocellular carcinoma (HCC) size ≤5 cm. Sixty-one LPSHs and 175 open parenchyma-sparing hepatectomies (OPSHs) for small-sized HCC were analyzed using a propensity score matching analysis. The median operative time was significantly shorter in the LPSH group (194 min) than in the OPSH group (275 minutes) ( P < 0.0001). The estimated blood loss was significantly lower in the LPSH group (100 mL) than in the OPSH group (380 mL) ( P < 0.0001). The incidences of superficial incisional surgical site infections and respiratory complications were significantly lower in the LPSH group than in the OPSH group ( P = 0.0161 and 0.0285, respectively). During the postoperative course, the white blood cell counts and C-reactive protein levels were significantly lower in the LPSH group. There were no differences in overall survival and disease-free survival ( P = 0.1293 and 0.4039, respectively), and no significant differences in terms of type of recurrence and site of intrahepatic recurrence ( P = 0.1410). The data from the present series suggest the lesser invasiveness and safety of LPSH even for small-sized HCC patients.

Fluorescence-Guided Surgery

Surgical resection of cancer remains an important treatment modality. Despite advances in preoperative imaging, surgery itself is primarily guided by the surgeon’s ability to locate pathology with conventional white light imaging. Fluorescence-guided surgery (FGS) can be used to define tumor location and margins during the procedure. Intraoperative visualization of tumors may not only allow more complete resections but also improve safety by avoiding unnecessary damage to normal tissue which can also reduce operative time and decrease the need for second-look surgeries. A number of new FGS imaging probes have recently been developed, complementing a small but useful number of existing probes. In this review, we describe current and new fluorescent probes that may assist FGS.

Laparoscopic versus open liver resection for colorectal liver metastases: a systematic review

BACKGROUND

Laparoscopic liver resection (LLR) has been proposed as a safe and feasible treatment option for colorectal liver metastasis (CRLM). However, the short-term and oncologic outcomes of LLR versus open liver resection (OLR) for CRLM have not been adequately assessed. Thus, we herein provide an updated systematic review comparing short-term and oncologic outcomes of CRLM patients undergoing LLR versus OLR.

METHODS

A systematic literature search was performed in the Pubmed, Embase, and Cochrane Library databases (until November 2, 2016) with a limitation to the publications in English. Quality assessment was performed based on the modification of the Newcastle-Ottawa Scale. Dichotomous data were calculated by odds ratio (OR), and continuous data were calculated by weighted mean difference (WMD) with 95% confidence intervals (CIs).

RESULTS

A total of 28 studies enrolling 4591 patients with CRLM were included. With respect to short-term outcomes, patients in LLR group showed significantly reduced blood loss (WMD: -143.64; 95% CI: -180.56 to -106.73; I2 = 86%; P < 0.001), lower operative transfusion requirement (OR: 0.40; 95% CI: 0.30-0.53; I2 = 0%; P < 0.001), shorter hospital stay (WMD: -2.47; 95% CI: -2.99 to -1.94; I2 = 82%; P < 0.001), reduced overall postoperative morbidity (OR: 0.53; 95% CI: 0.42-0.66; I2 = 38%; P < 0.001) and reduced severe morbidity (OR: 0.44; 95% CI: 0.32-0.60; I2 = 35%; P < 0.001). Regarding oncologic outcomes, there were no significant differences between the two surgical procedures in recurrence and 1-, 3-, and 5-overall survival and disease-free survival except for slightly higher R0 resection rate in LLR group was slightly higher than that of OLR group (OR: 1.43; 95% CI: 1.03-1.97; I2 = 37%; P = 0.03).

CONCLUSIONS

LLR should be the standard approach for selected patients with CRLM, and further research should focus on determining which patients would benefit most from LLR.

Indocyanine green fluorescence-guided surgery after IV injection in metastatic colorectal cancer: A systematic review

OBJECTIVE

Indocyanine green fluorescence-guided surgery (ICG-FGS) has emerged as a potential new imaging modality for improving the detection of hepatic, lymph node (LN), and peritoneal metastases in colorectal cancer (CRC) patients. The aim of this paper is to review the available literature in the clinical setting of ICG-FGS for tumoral detection in various fields of metastatic colorectal disease.

METHODS

PubMed and Medline literature databases were searched for original articles on the use of ICG in the setting of clinical studies on colorectal cancer. The search terms used were "near-infrared fluorescence", "intraoperative imaging", "indocyanine green", "human" and "colorectal cancer".

RESULTS

ICG fluorescence imaging (ICG-FI) is clearly supported as an intraoperative technique that allows the detection of additional superficial hepatic metastases of CRC. Data on the role of ICG-FI in the intraoperative detection of peritoneal metastases and LN metastases are scarce but encouraging and ICG-FI could potentially improve the staging and treatment of these patients.

CONCLUSION

ICG-FI is a promising imaging technique in the detection of small infraclinic LN, hepatic, and peritoneal metastatic deposits that may allow better staging and more complete surgical resection with a potential prognostic benefit for patients.

Laparoscopic Versus Open Liver Resection for Colorectal Liver Metastases: A Comprehensive Systematic Review and Meta-analysis

The effects of laparoscopic liver resection (LLR) and open liver resection (OLR) on oncological outcomes for colorectal cancer liver metastases (CCLM) remain inconclusive. Major databases were searched from January 1992 to October 2016. Effects of LLR vs OLR were determined. The primary endpoints were oncological outcomes. In total, 32 eligible non-randomized studies with 4697 patients (LLR: 1809, OLR: 2888) were analyzed. There were higher rates of clear surgical margins (OR: 1.64, 95%CI: 1.32 to 2.05, p < 0.00001) in the LLR group, without significant differences in disease recurrence, 3- or 5-year overall survival(OS) and disease free survival(DFS) between the two approaches. LLR was associated with less intraoperative blood loss (WMD: −147.46 [−195.78 to −99.15] mL, P < 0.00001) and fewer blood transfusions (OR: 0.41 [0.30–0.58], P < 0.00001), but with longer operation time (WMD:14.44 [1.01 to 27.88] min, P < 0.00001) compared to OLR. Less overall morbidity (OR: 0.64 [0.55 to 0.75], p < 0.00001) and shorter postoperative hospital stay (WMD: −2.36 [−3.06 to −1.66] d, p < 0.00001) were observed for patients undergoing LLR, while there was no statistical difference in mortality. LLR appears to be a safe and feasible alternative to OLR in the treatment of CCLM in selected patients.

From Detection to Resection: Photoacoustic Tomography and Surgery Guidance with Indocyanine Green Loaded Gold Nanorod@liposome Core-Shell Nanoparticles in Liver Cancer

Conventional imaging methods encounter challenges in diagnosing liver cancer that is less than 10 mm or without typical hypervascular features. With deep penetration and high spatial resolution imaging capability, the emerging photoacoustic tomography may offer better diagnostic efficacy for noninvasive liver cancer detection. Moreover, near-infrared fluorescence imaging-guided hepatectomy was proven to be able to identify nodules at the millimeter level. Thus, suitable photoacoustic and fluorescence dual-modality imaging probe may benefit patients in early diagnosis and complete resection. In this study, we fabricated indocyanine green loaded gold nanorod@liposome core-shell nanoparticles (Au@liposome-ICG) to integrate both imaging strategies. These nanoparticles exhibit superior biocompatibility, high stability, and enhanced dual-model imaging signals. Next, we explored their effectiveness of tumor detection and surgery guidance in orthotopic liver cancer mouse models. Histological analysis confirmed the accuracy of the probe in liver cancer detection and resection. This novel dual-modality nanoprobe holds promise for early diagnosis and better surgical outcome of liver cancer and has great potential for clinical translation.

What is the Optimal Timing for Liver Surgery of Resectable Synchronous Liver Metastases from Colorectal Cancer?

The optimal timing of the surgical strategy for colorectal cancer (CRC) presenting with resectable synchronous liver metastases remains unclear and controversial. The aim of this study was to compare simultaneous with staged resection, with respect to morbidity, mortality, and prognosis, including recurrence. A total of 107 patients who underwent initial hepatic resection for resectable synchronous liver metastasis from colorectal cancer were retrospectively analyzed. The 5-year disease-free survival rates were 16.4 per cent in the simultaneous group, and 24.0 per cent in the staged group (P = 0.5486). The 5-year overall survival rates were 70.7 per cent in the simultaneous group and 67.9 per cent in the staged group (P = 0.8254). Perioperative chemotherapy did not have a significant effect. Tumor depth of CRC (≥pT4) was the only key factor influencing prognosis. Postoperative intestinal anastomotic leakage occurred in nine patients (8.4%). On multivariate analysis, simultaneous surgery was shown to be the only independent risk factor for the occurrence of postoperative intestinal anastomotic leakage (P = 0.0163). In conclusion, neither timing of hepatic resection (simultaneous or staged) nor perioperative chemotherapy represented significant prognostic factors. The simultaneous surgery was the only independent risk factor for intestinal anastomotic leakage. Therefore, we recommend staged hepatic surgery for synchronous CRC and liver metastasis from colorectal cancer.

Affinity of Indocyanine Green in the Detection of Colorectal Peritoneal Carcinomatosis

Indocyanine green (ICG) is increasingly being used in digestive oncology. In colorectal cancer, ICG can be used to detect lymph node metastasis and hepatic metastasis on the surface of the liver. In peritoneal carcinomatosis, it was previously suspected that the diffusion of ICG in the tumor mass was due to the enhanced permeability and retention effect; however, this phenomenon has not been clearly demonstrated. Using bevacizumab, an antibody directed against vascular endothelial growth factor that consequently inhibits neoangiogenesis, we sought to confirm the mode of ICG diffusion. We compared the fluorescence of peritoneal carcinomatosis nodules from patients who had previously received bevacizumab during their oncologic treatment with those who did not receive this therapy. The sensitivity of the carcinomatosis nodule fluorescence was higher in the patients who did not receive bevacizumab compared with those who received the drug (76.3% and 65.0%, respectively). The rate of false-negative results was higher in the bevacizumab group than in the group that did not receive the drug (53.8% and 42.9%, respectively). Using bevacizumab, we demonstrate that the enhanced permeability and retention effect causes ICG accumulation in peritoneal carcinomatosis resulting from colorectal cancer.

Indocyanine green fluorescence imaging in hepatobiliary surgery

Indocyanine green (ICG) is a fluorescent dye that has been widely used for fluorescence imaging during hepatobiliary surgery. ICG is injected intravenously, selectively taken up by the liver, and then secreted into the bile. The catabolism and fluorescence properties of ICG permit a wide range of visualization methods in hepatobiliary surgery. We have characterized the applications of ICG during hepatobiliary surgery into: 1) liver mapping, 2) cholangiography, 3) tumor visualization, and 4) partial liver graft evaluation. In this literature review, we summarize the current understanding of ICG use during hepatobiliary surgery. Intra-operative ICG fluorescence imaging is a safe, simple, and feasible method that improves the visualization of hepatobiliary anatomy and liver tumors. Intravenous administration of ICG is not toxic and avoids the drawbacks of conventional imaging. In addition, it reduces post-operative complications without any known side effects. ICG fluorescence imaging provides a safe and reliable contrast for extra-hepatic cholangiography when detecting intra-hepatic bile leakage following liver resection. In addition, liver tumors can be visualized and well-differentiated hepatocellular carcinoma tumors can be accurately identified. Moreover, vascular reconstruction and outflow can be evaluated following partial liver transplantation. However, since tissue penetration is limited to 5-10mm, deeper tissue cannot be visualized using this method. Many instances of false positive or negative results have been reported, therefore further characterization is required.

Current status and future perspectives of fluorescence-guided surgery for cancer

Curative cancer surgery is dependent on the removal of all primary tumor and metastatic cancer cells. Preoperative imaging, intraoperative inspection and palpation, as well as pathological margin confirmation aid the surgeon, but these methods are lacking in sensitivity and can be highly subjective. Techniques in fluorescence-guided surgery (FGS) are emerging that selectively illuminate cancer cells, enhancing the distinction between tumors and surrounding tissues with the potential for single-cell sensitivity. FGS enhances tumor detection, surgical navigation, margin confirmation, and in some cases can be combined with therapeutic techniques to eliminate microscopic disease. In this review, we describe the preclinical developments and currently-used techniques for FGS.

Diverse applications for near infra-red intraoperative imaging

BACKGROUND

Near infra-red angiography using Indocyanine Green (ICG) has increasingly used as a tool for intraoperative diagnostics.

AIMS

The aim of this review is to explore the applications of ICG fluorescence angiography with particular emphasis on general surgical applications.

MATERIALS AND METHODS

A literature review was conducted to identify and summarise the diverse range of applications of ICG fluorescence.

RESULTS

ICG fluorescence angiography is increasingly used in a number of general surgical applications, including identification of colorectal liver metastases, assessment of skin flap perfusion, diagnosis of peritoneal endometriosis, ureteric identification, and localisation of colonic pathology.

DISCUSSION

ICG fluorescence angiography has clinical application in many areas as a tool for guiding surgical resection.

CONCLUSION

With the technological developments in near infra-red imaging it is likely that ICG fluorescence will play an increasing role in many routine surgical procedures.

Fluorescence detection of malignant liver tumors using 5-aminolevulinic acid-mediated photodynamic diagnosis: principles, technique, and clinical experience

BACKGROUND

Photoactive drugs selectively accumulate in malignant tissue specimens and cause drug-induced fluorescence. Photodynamic diagnosis (PDD) and fluorescence can distinguish normal from malignant tissue.

OBJECTIVE METHODS

From May 2012 to September 2013, a total of 70 patients underwent hepatic resections using 5-ALA-mediated PDD for liver tumors at our hospital.

RESULTS

5-ALA fluorescence was detected in all hepatocellular carcinoma cases with serosa invasion. In liver metastasis from colorectal cancer cases with serosa invasion, 18 patients (85.7 %) were detected, and three patients (14.2 %) whose tumors showed complete response to neoadjuvant chemotherapy showed no fluorescence. Both superficial and deep malignant liver tumors were detected with 92.5 % sensitivity. Using 5-ALA-mediated PDD, tumors remaining at the cut surface and postoperative bile leakage were less frequent than in our previous hepatic resections using conventional white-light observation. Moreover, all malignant liver tumors were completely removed with a clear microscopic margin using 5-ALA, with a significant difference in resection margin width between 5-ALA-mediated PDD (6.7 ± 6.9 mm) and white-light observation (9.2 ± 7.0 mm; p = 0.0083).

CONCLUSIONS

With the detection of malignant liver tumors, residual tumor and bile leakage at the cut surface of the remnant liver were improved by PDD with 5-ALA. This procedure may provide greater sensitivity than the conventional procedure. Furthermore, 5-ALA-mediated PDD can ensure histological clearance regardless of the resection margin and preserve as much liver parenchyma as possible in patients with impaired liver function.

Fluorescence in robotic surgery

Currently, there are several clinical applications for intraoperative ICG, such as identification of vascular and biliary anatomy, assessment of organ and tissue perfusion, lymph node mapping, and real-time identification of lesions. In this paper we present a review of the available literature related to the use of ICG fluorescence in robotic surgery in order to provide a better understanding of the current applications, show the rapid growth of this technique, and demonstrate the potential future applications.

Dynamic fluorescent imaging with indocyanine green for monitoring the therapeutic effects of photoimmunotherapy

A new type of monoclonal antibody (mAb)-based, highly specific phototherapy (photoimmunotherapy; PIT) that uses a near-infrared (NIR) phthalocyanine dye, IRDye700DX (IR700) conjugated with an mAb, has recently been described. NIR light exposure leads to immediate, target-selective necrotic cell death. However, tumor shrinkage takes several days to occur, making it difficult to detect earlier changes in the tumor. In this study, Panitumumab targeting the epidermal growth factor receptor (EGFR1) conjugated to IR700 was used to treat EGFR-expressing A431 tumor cells and in vivo xenografts. PIT was performed at varying doses of NIR light (10, 30, 50 and 100 J cm(-2)) in xenograft tumors in mice. Indocyanine green (ICG) dynamic imaging was evaluated for monitoring cytotoxic effects for the first hour after PIT. Our results demonstrated a statistical difference (p < 0.05) in ICG intensity between control and PIT treated tumors in the higher light exposure groups (50 J cm(-2): 2.94 ± 0.35 vs 5.22 ± 0.92, p = 0.02; and 100 J cm(-2) : 3.56 ± 0.96 vs 5.71 ± 1.43, p = 0.008) as early as 20 min post ICG injection. However, no significant difference (p > 0.05) in ICG intensity between control and PIT treated tumors was evident in the lower light exposure group at any time points up to 60 min (10 J cm(-2) : 1.92 ± 0.49 vs 1.71 ± 0.3, p = 0.44; and 30 J cm(-2): 1.57 ± 0.35 vs 2.75 ± 0.59, p = 0.07). Similarly, the retention index (background to corrected uptake ratio of ICG) varied with light exposure. In conclusion, ICG may serve as a potential indicator of acute cytotoxic effects of mAb-IR700-induced PIT even before morphological changes can be seen in targeted tumors.

Usefulness of intraoperative diagnosis of hepatic tumors located at the liver surface and hepatic segmental visualization using indocyanine green-photodynamic eye imaging

BACKGROUND

To improve the diagnostic accuracy for hepatic tumors on the liver surface, we investigated the usefulness of an indocyanine green-photodynamic eye (ICG-PDE) system by comparison with Sonazoid intraoperative ultrasonography (IOUS) in 117 patients. Hepatic segmentation by ICG-PDE was also evaluated.

METHODS

ICG was administered preoperatively for functional testing and images of the tumor were observed during hepatectomy using a PDE camera. ICG was injected into portal veins to determine hepatic segmentation.

RESULTS

Accurate diagnosis of liver tumors was achieved with ICG-PDE in 75% of patients, lower than with IOUS (94%). False-positive and false-negative diagnosis rates for ICG-PDE were 24% and 9%, respectively. New small HCCs were detected in 3 patients. The ICG fluorescent pattern in tumors was strong staining in 41%, weak staining in 13%, rim staining in 20% and no staining in 26%. Hepatocellular carcinoma predominantly showed strong staining (61%), while rim staining predominated in cholangiocellular carcinoma (60%) and liver metastasis (55%). Hepatic segmental staining was performed in 28 patients, proving successful in 89%.

CONCLUSION

ICG-PDE is a useful tool for detecting the precise tumor location at the liver surface, identifying new small tumors, and determining liver segmentation for liver resection.