Fluorescent cholangiography during laparoscopic cholecystectomy: indocyanine green or new fluorescent agents?

Technical Note: Are Currently Used Measurements of Fluorescence Intensity in Near Infrared Fluorescence Imaging During Laparoscopic Cholecystectomy Comparable?

Aims: To investigate whether different calculation methods to express fluorescence intensity (FI) as target-to-background (BG) ratio are comparable and which method(s) match with human perception. Materials and Methods: Comparison of three calculation methods from current literature (OsiriX^®, ImageJ^®, and Photoshop^®) to objectify FI during laparoscopic cholecystectomy measured at the exact same locations within recorded images of two categories: ex vivo and in vivo. Currently applied formulas to present FI in relation to the BG signal are compared with the subjective assessment by the human observers. These three formulas are Signal contrast = (FI in fluorescence regions-FI in BG)/255; Target-to-background ratio = (FI of target-FI of BG)/FI of BG; Signal-to-background ratio = FI of cystic duct/FI of liver and Target-to-background ratio = (FI of target-noise)/(FI of BG-noise). Results: In our evaluation OsiriX and ImageJ provided similar results, whereas OsiriX values were structurally slightly lower compared with ImageJ. Values obtained through Photoshop were less evidently related to those obtained with OsiriX and ImageJ. The formula Target-to-background ratio = (FI of target-noise)/(FI of BG-noise) was less corresponding with human perception compared with the other used formulas. Conclusions: FI results based on measurements using the programs OsiriX and ImageJ are similar, allowing for comparison of results between these programs. Results using Photoshop differ significantly, making direct comparison impossible. This is an important finding when interpreting study results. We propose to report both target and BG FI in articles, so that proper interpretation between articles can be made.

Fluorescence guided surgery in liver tumors: applications and advantages

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

Near-infrared fluorescent cholangiography - real-time visualization of the biliary tree during elective laparoscopic cholecystectomy

BACKGROUND

The purpose was to evaluate the efficacy of near-infrared fluorescent cholangiography (FC) in real-time visualization of the biliary tree during elective laparoscopic cholecystectomy.

METHODS

Fifty consecutive elective laparoscopic cholecystectomies were performed with fluorescent cholangiography. FC was performed at three time points: following exposure of Calot's triangle, prior to any dissection; and after partial and complete dissection of Calot's triangle.

RESULTS

The cystic duct (CD) was identified successfully by FC in 43 of 50 patients (86%) and in 45 of 50 patients (90%) before and after Calot's dissection respectively (p > 0.05). The common hepatic duct (CHD) and the common bile duct (CBD) were identified successfully in 12 of 50 patients (24%) and in 33 of 50 patients (66%) before Calot's dissection respectively and in 26 of 50 patients (52%) and in 47 of 50 patients (94%) after complete Calot's dissection (p = 0.007 and p = 0.001, respectively). Significant differences were observed for CBD visualization rate, in relation to BMI after Calot's dissection (p < 0.05) and history of cholecystitis, before Calot's dissection (p = 0.017). No bile duct injuries were reported.

CONCLUSION

Fluorescent cholangiography can be considered as a useful tool for intra-operative visualization of the biliary tree during laparoscopic cholecystectomies.

Bile Duct Injury after Cholecystectomy: Surgical Therapy

BACKGROUND

Iatrogenic bile duct injuries (IBDI) after laparoscopic cholecystectomy (LC), being one of the most common performed surgical procedures, remain a substantial problem in gastrointestinal surgery. The most important aspect regarding this issue is the prevention of IBDI during index cholecystectomy. Once it occurs, early and accurate diagnosis of IBDI is very important for surgeons and gastroenterologists, because unidentified IBDI may result in severe complications such as hepatic failure and death. Laboratory tests, radiological imaging, and endoscopy play an important role in the diagnosis of biliary injuries.

METHODS

This review summarizes and discusses the current literature on the management of IBDI after LC from a surgical point of view.

RESULTS AND CONCLUSION

In general, endoscopic techniques are recommended for the initial diagnosis and treatment of IBDI and are important to classify them correctly. In patients with complete dissection or obstruction of the bile duct, surgical management remains the only feasible option. Different surgical reconstructions are performed in patients with IBDI. According to the available literature, Roux-en-Y hepaticojejunostomy is the most frequent surgical reconstruction and is recommended by most authors. Long-term results are most important in the assessment of effectiveness of IBDI treatment. Apart from that, adequate diagnosis and treatment of IBDI may avoid many serious complications and improve the quality of life of our patients.

Utility of fluorescent cholangiography during laparoscopic cholecystectomy: A systematic review

AIM

To verify the utility of fluorescent cholangiography for more rigorous identification of the extrahepatic biliary system.

METHODS

MEDLINE and PubMed searches were performed using the key words "fluorescent cholangiography", "fluorescent angiography", "intraoperative fluorescent imaging", and "laparoscopic cholecystectomy" in order to identify relevant articles published in English, French, German, and Italian during the years of 2009 to 2014. Reference lists from the articles were reviewed to identify additional pertinent articles. For studies published in languages other than those mentioned above, all available information was collected from their English abstracts. Retrieved manuscripts (case reports, reviews, and abstracts) concerning the application of fluorescent cholangiography were reviewed by the authors, and the data were extracted using a standardized collection tool. Data were subsequently analyzed with descriptive statistics. In contrast to classic meta-analyses, statistical analysis was performed where the outcome was calculated as the percentages of an event (without comparison) in pseudo-cohorts of observed patients.

RESULTS

A total of 16 studies were found that involved fluorescent cholangiography during standard laparoscopic cholecystectomies (n = 11), single-incision robotic cholecystectomies (n = 3), multiport robotic cholecystectomy (n = 1), and single-incision laparoscopic cholecystectomy (n = 1). Overall, these preliminary studies indicated that this novel technique was highly sensitive for the detection of important biliary anatomy and could facilitate the prevention of bile duct injuries. The structures effectively identified before dissection of Calot's triangle included the cystic duct (CD), the common hepatic duct (CHD), the common bile duct (CBD), and the CD-CHD junction. A review of the literature revealed that the frequencies of detection of the extrahepatic biliary system ranged from 71.4% to 100% for the CD, 33.3% to 100% for the CHD, 50% to 100% for the CBD, and 25% to 100% for the CD-CHD junction. However, the frequency of visualization of the CD and the CBD were reduced in patients with a body mass index > 35 kg/m(2) relative to those with a body mass index < 35 kg/m(2) (91.0% and 64.0% vs 92.3% and 71.8%, respectively).

CONCLUSION

Fluorescent cholangiography is a safe procedure enabling real-time visualization of bile duct anatomy and may become standard practice to prevent bile duct injury during laparoscopic cholecystectomy.

Fluorescent imaging of the biliary tract during laparoscopic cholecystectomy

The introduction of laparoscopic cholecystectomy was associated with increased incidences of bile duct injury. The primary cause appears to be misidentification of the biliary anatomy. Routine intra-operative cholangiography has been recommended to reduce accidental duct injury, although in practice it is more often reserved for selected cases. There has been interest in the use of fluorescent agents excreted via the biliary system to enable real-time intra-operative imaging, to aid the laparoscopic surgeon in correctly interpreting the anatomy. The primary aim of this review is to evaluate the ability of fluorescent cholangiography to identify important biliary anatomy intra-operatively. Secondary aims are to investigate its ability to detect important intra-operative pathology such as bile leaks, identify potential alternative fluorophores, and evaluate the evidence regarding patient outcomes.

Indocyanine green fluorescence imaging in the surgical management of liver cancers: current facts and future implications

Imaging detection of liver cancers and identification of the bile ducts during surgery, based on the fluorescence properties of indocyanine green, has recently been developed in liver surgery. The principle of this imaging technique relies on the intravenous administration of indocyanine green before surgery and the illumination of the surface of the liver by an infrared camera that simultaneously induces and collects the fluorescence. Detection by fluorescence is based on the contrast between the (fluorescent) tumoral or peri-tumoral tissues and the healthy (non-fluorescent) liver. Results suggest that indocyanine green fluorescence imaging is capable of identification of new liver cancers and enables the characterization of known hepatic lesions in real time during liver resection. The purpose of this paper is to present the fundamental principles of fluorescence imaging detection, to describe successively the practical and technical aspects of its use and the appearance of hepatic lesions in fluorescence, and to expose the diagnostic and therapeutic perspectives of this innovative imaging technique in liver surgery.

Real-time near-infrared fluorescent cholangiography could shorten operative time during robotic single-site cholecystectomy

BACKGROUND

With the introduction of a new platform, robotic single-site cholecystectomy (RSSC) has been reported as feasible and safe for selected cases. In parallel, the development of real-time near-infrared fluorescent cholangiography using indocyanine green (ICG) has been seen as a help during the dissection, even if the data are still preliminary. The study purpose is to report our experience with ICG RSSC and compare the outcomes to standard RSSC.

METHODS

From February 2011 to December 2011, 44 selected patients underwent RSSC for symptomatic cholelithiasis. Among them, 23 (52.3%) were included in an experimental protocol using the ICG, and the remainder (47.7%) underwent standard RSSC. There was no randomization. The endpoints were the perioperative outcomes. This is a prospective study, approved by our local Ethics Committee.

RESULTS

There were no differences in terms of patients' characteristics, except that there were more male patients in the ICG group (47.8 vs. 9.5%; p = 0.008). Regarding the surgical data, the overall operative time was shorter for the ICG group, especially for patients with a body mass index (BMI) ≤25 (-24 min) but without reaching statistical significance (p = 0.06). For BMI >25, no differences were observed. Otherwise, there were no differences in terms of conversion, complications, or length of stay between both groups.

CONCLUSIONS

A RSSC with a real-time near-infrared fluorescent cholangiography can be performed safely. In addition, for selected patients with a low BMI, ICG could shorten the operative time during RSSC. Larger studies are still required before drawing definitive conclusions.

Fluorescence imaging in surgery

Although the modern surgical era is highlighted by multiple technological advances and innovations, one area that has remained constant is the dependence of the surgeon's vision on white-light reflectance. This renders different body tissues in a limited palette of various shades of pink and red, thereby limiting the visual contrast available to the operating surgeon. Healthy tissue, anatomic variations, and diseased states are seen as slight discolorations relative to each other and differences are inherently limited in dynamic range. In the upcoming years, surgery will undergo a paradigm shift with the use of targeted fluorescence imaging probes aimed at augmenting the surgical armamentarium by expanding the "visible" spectrum available to surgeons. Such fluorescent "smart probes" will provide real-time, intraoperative, pseudo-color, high-contrast delineation of both normal and pathologic tissues. Fluorescent surgical molecular guidance promises another major leap forward to improve patient safety and clinical outcomes, and to reduce overall healthcare costs. This review provides an overview of current and future surgical applications of fluorescence imaging in diseased and nondiseased tissues and focus on the innovative fields of image processing and instrumentation.

Near infrared fluorescence for image-guided surgery

Near infrared (NIR) image-guided surgery holds great promise for improved surgical outcomes. A number of NIR image-guided surgical systems are currently in preclinical and clinical development with a few approved for limited clinical use. In order to wield the full power of NIR image-guided surgery, clinically available tissue and disease specific NIR fluorophores with high signal to background ratio are necessary. In the current review, the status of NIR image-guided surgery is discussed along with the desired chemical and biological properties of NIR fluorophores. Lastly, tissue and disease targeting strategies for NIR fluorophores are reviewed.