Misinterpretation of the severity of bile duct injuries by MRCP.

BACKGROUND: Magnetic resonance imaging (MRI) is widely regarded as the gold standard for assessment of the bile ducts in patients with bile duct injuries (BDIs). This case series aims to highlight the shortcomings of this imaging modality and demonstrate how it may overestimate the injury severity. METHODS: Three patients treated at Groote Schuur Hospital and the University of Cape Town in whom MRI/magnetic resonance cholangiopancreatography (MRCP) overestimated the severity of BDI were included in the study. Demographic characteristics, clinical presentation, blood results and imaging findings are presented. RESULTS: All patients had an MRI/MRCP done which assessed the BDIs as major complete cut-off of the proximal common hepatic duct with substance loss. Subsequent direct cholangiography showed minor injuries and all three patients were successfully managed with endoscopic stenting. CONCLUSION: Major BDIs are complex, and assessment of severity is intricate and may be overestimated. These patients are best managed in high-volume multidisciplinary team settings.

Quantitative MRCP and metrics of bile duct disease over time in patients with primary sclerosing cholangitis: A prospective study.

BACKGROUND: Imaging markers of biliary disease in primary sclerosing cholangitis (PSC) have potential for use in clinical and trial disease monitoring. Herein, we evaluate how quantitative magnetic resonance cholangiopancreatography (MRCP) metrics change over time, as per the natural history of disease. METHODS: Individuals with PSC were prospectively scanned using non-contrast MRCP. Quantitative metrics were calculated using MRCP+ post-processing software to assess duct diameters and dilated and strictured regions. Additionally, a hepatopancreatobiliary radiologist (blinded to clinical details, biochemistry and quantitative biliary metrics) reported each scan, including ductal disease assessment according to the modified Amsterdam Cholangiographic Score (MAS). RESULTS: At baseline, 14 quantitative MRCP+ metrics were found to be significantly different in patients with PSC (N = 55) compared to those with primary biliary cholangitis (N = 55), autoimmune hepatitis (N = 57) and healthy controls (N = 18). In PSC specifically, baseline metrics quantifying the number of strictures and the number and length of bile ducts correlated with the MAS, transient elastography and serum ALP values (p < 0.01 for all correlations). Over a median 371-day follow-up (range: 364-462), 29 patients with PSC underwent repeat MRCP, of whom 15 exhibited quantitative changes in MRCP+ metrics. Compared to baseline, quantitative MRCP+ identified an increasing number of strictures over time (p < 0.05). Comparatively, no significant differences in biochemistry, elastography or the MAS were observed between timepoints. Quantitative MRCP+ metrics remained stable in non-PSC liver disease. CONCLUSION: Quantitative MRCP+ identifies changes in ductal disease over time in PSC, despite stability in biochemistry, liver stiffness and radiologist-derived cholangiographic assessment (trial registration: ISRCTN39463479).

Diseases of bile duct in children.

Several diseases originate from bile duct pathology. Despite studies on these diseases, certain etiologies of some of them still cannot be concluded. The most common disease of the bile duct in newborns is biliary atresia, whose prognosis varies according to the age of surgical correction. Other diseases such as Alagille syndrome, inspissated bile duct syndrome, and choledochal cysts are also time-sensitive because they can cause severe liver damage due to obstruction. The majority of these diseases present with cholestatic jaundice in the newborn or infant period, which is quite difficult to differentiate regarding clinical acumen and initial investigations. Intraoperative cholangiography is potentially necessary to make an accurate diagnosis, and further treatment will be performed synchronously or planned as findings suggest. This article provides a concise review of bile duct diseases, with interesting cases.

[Double extrahepatic bile duct with pancreaticobiliary maljunction:a case report].

A 76-year-old woman with a suspected double extrahepatic bile duct was referred to our hospital. MRCP revealed that the left hepatic and posterior ducts combined to form the ventral bile duct and that the anterior duct formed the dorsal bile duct. ERCP demonstrated that the ventral bile duct was linked with the Wirsung duct. Amylase levels in the bile were unusually high. Based on these findings, we diagnosed a double extrahepatic bile duct with pancreaticobiliary maljunction and choledocholithiasis. Duplicate bile duct resection and bile duct jejunal anastomosis were performed considering the risk of biliary cancer due to pancreaticobiliary maljunction. The resected bile duct epithelium demonstrated no atypia or hyperplastic changes.

Multiscale X-ray phase-contrast CT unveils the evolution of bile infarct in obstructive biliary disease.

Bile infarct is a pivotal characteristic of obstructive biliary disease, but its evolution during the disease progression remains unclear. Our objective, therefore, is to explore morphological alterations of the bile infarct in the disease course by means of multiscale X-ray phase-contrast CT. Bile duct ligation is performed in mice to mimic the obstructive biliary disease. Intact liver lobes of the mice are scanned by phase-contrast CT at various resolution scales. Phase-contrast CT clearly presents three-dimensional (3D) images of the bile infarcts down to the submicron level with good correlation with histological images. The CT data illustrates that the infarct first appears on day 1 post-BDL, while a microchannel between the infarct and hepatic sinusoids is identified, the number of which increases with the disease progression. A 3D model of hepatic acinus is proposed, in which the infarct starts around the portal veins (zone I) and gradually progresses towards the central veins (zone III) during the disease process. Multiscale phase-contrast CT offers the comprehensive analysis of the evolutionary features of the bile infarct in obstructive biliary disease. During the course of the disease, the bile infarcts develop infarct-sinusoidal microchannels and gradually occupy the whole liver, promoting the disease progression.

Using neural networks to autonomously assess adequacy in intraoperative cholangiograms.

BACKGROUND: Intraoperative cholangiography (IOC) is a contrast-enhanced X-ray acquired during laparoscopic cholecystectomy. IOC images the biliary tree whereby filling defects, anatomical anomalies and duct injuries can be identified. In Australia, IOC are performed in over 81% of cholecystectomies compared with 20 to 30% internationally (Welfare AIoHa in Australian Atlas of Healthcare Variation, 2017). In this study, we aim to train artificial intelligence (AI) algorithms to interpret anatomy and recognise abnormalities in IOC images. This has potential utility in (a) intraoperative safety mechanisms to limit the risk of missed ductal injury or stone, (b) surgical training and coaching, and (c) auditing of cholangiogram quality. METHODOLOGY: Semantic segmentation masks were applied to a dataset of 1000 cholangiograms with 10 classes. Classes corresponded to anatomy, filling defects and the cholangiogram catheter instrument. Segmentation masks were applied by a surgical trainee and reviewed by a radiologist. Two convolutional neural networks (CNNs), DeeplabV3+ and U-Net, were trained and validated using 900 (90%) labelled frames. Testing was conducted on 100 (10%) hold-out frames. CNN generated segmentation class masks were compared with ground truth segmentation masks to evaluate performance according to a pixel-wise comparison. RESULTS: The trained CNNs recognised all classes.. U-Net and DeeplabV3+ achieved a mean F1 of 0.64 and 0.70 respectively in class segmentation, excluding the background class. The presence of individual classes was correctly recognised in over 80% of cases. Given the limited local dataset, these results provide proof of concept in the development of an accurate and clinically useful tool to aid in the interpretation and quality control of intraoperative cholangiograms. CONCLUSION: Our results demonstrate that a CNN can be trained to identify anatomical structures in IOC images. Future performance can be improved with the use of larger, more diverse training datasets. Implementation of this technology may provide cholangiogram quality control and improve intraoperative detection of ductal injuries or ductal injuries.

Novel 3D morphological characteristics for congenital biliary dilatation diagnosis: a case-control study.

BACKGROUND: Congenital biliary dilatation (CBD) necessitates the timely removal of dilated bile ducts. Accurate differentiation between CBD and secondary biliary dilatation (SBD) is crucial for treatment decisions, and identification of CBD with intrahepatic involvement is vital for surgical planning and supportive care. This study aimed to develop quantitative models based on bile duct morphology to distinguish CBD from SBD and further identify CBD with intrahepatic involvement. MATERIALS AND METHODS: The retrospective study included 131 CBD and 209 SBD patients between December 2014 and December 2021 for model development, internal validation, and testing. A separate cohort of 15 CBD and 34 SBD patients between January 2022 and December 2022 was recruited for temporally-independent validation. Quantitative shape-based (Shape) and diameter-based (Diam) morphological characteristics of bile ducts were extracted to build a CBD diagnosis model to distinguish CBD from SBD and an intrahepatic involvement identification model to classify CBD with/without intrahepatic involvement. The diagnostic performance of the models was compared with that of experienced hepatobiliary surgeons. RESULTS: The CBD diagnosis model using clinical, Shape, and Diam characteristics showed good performance with an AUROC of 0.942 (95% CI: 0.890-0.994), AUPRC of 0.917 (0.855-0.979), accuracy of 0.891, sensitivity of 0.950, and F1-score of 0.864. The model outperformed two experienced surgeons in accuracy, sensitivity, and F1-score. The intrahepatic involvement identification model using clinical, Shape, and Diam characteristics yielded outstanding performance with an AUROC of 0.944 (0.879-1.000), AUPRC of 0.982 (0.947-1.000), accuracy of 0.932, sensitivity of 0.971, and F1-score of 0.957. The models demonstrated generalizable performance on the temporally-independent validation cohort. CONCLUSIONS: This study developed two robust quantitative models for distinguishing CBD from SBD and identifying CBD with intrahepatic involvement, respectively, based on morphological characteristics of the bile ducts, showing great potential in risk stratification and surgical planning of CBD.

An atypical case of isolated immunoglobulin G4-related sclerosing cholangitis with a cholangiogram resembling primary sclerosing cholangitis.

An asymptomatic 77-year-old man with intrahepatic bile duct dilation was referred to our hospital. Cholangiography revealed alternations between strictures and dilated segments from the right and left hepatic ducts to the lower bile ducts, with findings of a pruned tree, beaded, shaggy appearance, and diverticulum-like outpouching. Histopathology revealed abundant immunoglobulin G4 (IgG4)-positive plasma cells (> 10 per high-power field) with an IgG4/IgG-positive cell ratio of 40-50%. After 2 weeks of steroid therapy, the cholangiography markedly improved. Because the cholangiographic findings resembled those of primary sclerosing cholangitis, steroid therapy proved useful in differentiating IgG4-related sclerosing cholangitis from primary sclerosing cholangitis.

Variations in the cystic duct: frequency and the relationship among insertion sides and heights on the bile duct.

BACKGROUND: Evaluation of the cystic duct anatomy prior to bile duct or gallbladder surgery is important, to decrease the risk of bile duct injury. This study aimed to clarify the frequency of cystic duct variations and the relationship between them. METHODS: Data of 205 patients who underwent cholecystectomy after imaging at Sada Hospital, Japan, were analyzed. The Chi-square test was used to analyze the relationships among variations. RESULTS: The lateral and posterior sides of the bile duct were the two most common insertion points (92 patients, 44.9%), and the middle height was the most common insertion height (135 patients, 65.9%). Clinically important variations (spiral courses, parallel courses, low insertions, and right hepatic duct draining) relating to the risk of bile duct injury were observed in 24 patients (11.7%). Regarding the relationship between the insertion sides and heights, we noticed that the posterior insertion frequently existed in low insertions (75.0%, P < 0.001) and did not exist in high insertions. In contrast, the anterior insertion coexisted with high and never low insertions. Spiral courses have two courses: anterior and posterior, and anterior ones were only found in high insertion cases. CONCLUSIONS: The insertion point of the cystic duct and the spiral courses tended to be anterior or lateral superiorly and posterior inferiorly. Clinically significant variations in cystic duct insertions are common and surgeons should be cautious about these variations to avoid complications.

Factors Associated With Difficult Endoscopic Ultrasonography-guided Biliary Drainage.

BACKGROUND AND AIMS: When endoscopic retrograde cholangiopancreatography-guided biliary drainage is challenging, endoscopic ultrasound-guided biliary drainage (EUS-BD) can be used as an alternate treatment; however, this method requires operator expertise. Therefore, this study aimed to clarify the factors that are associated with a difficult EUS-BD. PATIENTS AND METHODS: Patients who successfully underwent EUS-BD were enrolled in this study. The patients were divided into the easy group and difficult group depending on whether the procedural time was more than 60 minutes, which was the cutoff value elicited from past reports. Patient characteristics and procedural factors were compared between the two groups. The factors associated with difficult procedures were also investigated. RESULTS: The patient characteristics were not significantly different between the easy group (n=22) and the difficult group (n=19). The diameter of the punctured bile duct was significantly different between the two groups. In the multivariate analysis, the diameter of the punctured bile duct was the only factor associated with a difficult EUS-BD (odds ratio 0.65, 95% confidence interval 0.46-0.91, P value=0.012). The cutoff value for the diameter of the punctured bile duct in predicting a difficult EUS-BD was 7.0 mm (area under the curve: 0.83, sensitivity 84.2%, specificity 86.4%). CONCLUSIONS: A nondilated bile duct might be a predictive factor for a difficult EUS-BD. For beginners of EUS-BD, the cutoff value for the punctured bile duct diameter found in this study, 7.0 mm, might become a barometer for puncture point selection.

Endoscopic ultrasound-rendezvous versus percutaneous-endoscopic rendezvous endoscopic retrograde cholangiopancreatography for bile duct access: Systematic review and meta-analysis.

OBJECTIVES: Endoscopic ultrasound (EUS) or percutaneous-assisted antegrade guidewire insertion can be used to achieve biliary access when standard endoscopic retrograde cholangiopancreatography (ERCP) fails. We conducted a systematic review and meta-analysis to evaluate and compare the effectiveness and safety of EUS-assisted rendezvous (EUS-RV) and percutaneous rendezvous (PERC-RV) ERCP. METHODS: We searched multiple databases from inception to September 2022 to identify studies reporting on EUS-RV and PERC-RV in failed ERCP. A random-effects model was used to summarize the pooled rates of technical success and adverse events with 95% confidence interval (CI). RESULTS: In total, 524 patients (19 studies) and 591 patients (12 studies) were managed by EUS-RV and PERC-RV, respectively. The pooled technical successes were 88.7% (95% CI 84.6-92.8%, I2 = 70.5%) for EUS-RV and 94.1% (95% CI 91.1-97.1%, I2 = 59.2%) for PERC-RV (P = 0.088). The technical success rates of EUS-RV and PERC-RV were comparable in subgroups of benign diseases (89.2% vs. 95.8%, P = 0.068), malignant diseases (90.3% vs. 95.5%, P = 0.193), and normal anatomy (90.7% vs. 95.9%, P = 0.240). However, patients with surgically altered anatomy had poorer technical success after EUS-RV than after PERC-RV (58.7% vs. 93.1%, P = 0.036). The pooled rates of overall adverse events were 9.8% for EUS-RV and 13.4% for PERC-RV (P = 0.686). CONCLUSIONS: Both EUS-RV and PERC-RV have exhibited high technical success rates. When standard ERCP fails, EUS-RV and PERC-RV are comparably effective rescue techniques if adequate expertise and facilities are feasible. However, in patients with surgically altered anatomy, PERC-RV might be the preferred choice over EUS-RV because of its higher technical success rate.

Donor bile duct evaluation with magnetic resonance cholangiography in living-donor liver transplantation: a novel anatomical classification for predicting surgical techniques.

PURPOSE: To propose a novel, inclusive classification that facilitates the selection of the appropriate donor and surgical technique in living-donor liver transplantation (LDLT). METHODS: The magnetic resonance cholangiography examinations of 201 healthy liver donors were retrospectively evaluated. The study group was classified according to the proposed classification. The findings were compared with the surgical technique used in 93 patients who underwent transplantation. The Couinaud, Huang, Karakas, Choi, and Ohkubo classifications were also applied to all cases. RESULTS: There were 118 right-lobe donors (58.7%) and 83 left-lateral-segment donors (41.3%). Fifty-six (28.8%) of the cases were classified as type 1, 136 (67.7%) as type 2, and 7 (3.5%) as type 3 in the proposed classification; all cases could be classified. The number of individuals able to become liver donors was 93. A total of 36 cases were type 1, 56 were type 2, and 1 was type 3. Of the type 1 donors, 83% required single anastomosis during transplantation, whereas six patients classified as type 1 required two anastomoses, all of which were caused by technical challenges during resection. Moreover, 51.8% of the cases classified as type 2 required additional anastomosis during transplantation. The type 3 patient required three anastomoses. The type 1 and type 2 donors required a different number of anastomoses (P < 0.001). CONCLUSION: The proposed classification in this study includes all anatomical variations. This inclusive classification accurately predicts the surgical technique for LDLT.

Identification of the ideal weight-based indocyanine green dose for fluorescent cholangiography.

BACKGROUND: Ideal visualization of fluorescent cholangiography during laparoscopic cholecystectomy is when maximum fluorescence into biliary ducts and absent signal into liver parenchyma, defined as "signal to background ratio" (SBR), is obtained. Such condition is mainly dependent by indocyanine green (ICG) dose and timing. The aim of this study was to identify the ideal ICG dose to obtain the best possible intraoperative visualization of the extra-hepatic biliary tree. METHODS: The first part of the study was used to define a range of small weight-based ICG dosages using the mathematical function bisection method. During the second part of the study, the midpoint dose of the identified range, was tested in 50 consecutive cholecystectomies using a laser-based fluorescence laparoscopic camera (SynergyID system by Arthrex, Naples, FL, USA). Timing administration was set at 1 h before surgery, since this is the most common situation in clinical practice. Fluorescence intensity of bile ducts and liver parenchyma were assessed both subjectively, by blinded operative surgeon, as well as objectively, using an image analysis software (Fiji plugin), before and after Calot's triangle dissection. RESULTS: Fourteen patients were included in the first part of the study and ICG dose between 0.01191406 and 0.0119873 mg/kg was identified. The second part confirmed previous results after testing the dosage equal to 0.0119 mg/kg (midpoint of the defined range) in 50 consecutive cholecystectomies. Cystic duct was identified in 66 and 100% of cases before and after dissection of Calot's triangle respectively. On the other hand, common bile duct was identified in 82 and 92% before and after dissection respectively. Subjective and objective SBRs confirmed the benefit of the identified ICG dose. CONCLUSION: ICG dose calculated by 0.0119 mg/kg administered one hour before surgery allows an ideal intraoperative visualization of the extra-hepatic biliary tree. REGISTRATION NUMBER: ISRCTN10190039.

Towards reliable hepatocytic anatomy segmentation in laparoscopic cholecystectomy using U-Net with Auto-Encoder.

BACKGROUND: Most bile duct (BDI) injuries during laparoscopic cholecystectomy (LC) occur due to visual misperception leading to the misinterpretation of anatomy. Deep learning (DL) models for surgical video analysis could, therefore, support visual tasks such as identifying critical view of safety (CVS). This study aims to develop a prediction model of CVS during LC. This aim is accomplished using a deep neural network integrated with a segmentation model that is capable of highlighting hepatocytic anatomy. METHODS: Still images from LC videos were annotated with four hepatocystic landmarks of anatomy segmentation. A deep autoencoder neural network with U-Net to investigate accurate medical image segmentation was trained and tested using fivefold cross-validation. Accuracy, Loss, Intersection over Union (IoU), Precision, Recall, and Hausdorff Distance were computed to evaluate the model performance versus the annotated ground truth. RESULTS: A total of 1550 images from 200 LC videos were annotated. Mean IoU for segmentation was 74.65%. The proposed approach performed well for automatic hepatocytic landmarks identification with 92% accuracy and 93.9% precision and can segment challenging cases. CONCLUSION: DL, can potentially provide an intraoperative model for surgical video analysis and can be trained to guide surgeons toward reliable hepatocytic anatomy segmentation and produce selective video documentation of this safety step of LC.

Real-time continuous image guidance for endoscopic retrograde cholangiopancreatography based on 3D/2D registration and respiratory compensation.

BACKGROUND: It has been confirmed that three-dimensional (3D) imaging allows easier identification of bile duct anatomy and intraoperative guidance of endoscopic retrograde cholangiopancreatography (ERCP), which reduces the radiation dose and procedure time with improved safety. However, current 3D biliary imaging does not have good real-time fusion with intraoperative imaging, a process meant to overcome the influence of intraoperative respiratory motion and guide navigation. The present study explored the feasibility of real-time continuous image-guided ERCP. AIM: To explore the feasibility of real-time continuous image-guided ERCP. METHODS: We selected 2 3D-printed abdominal biliary tract models with different structures to simulate different patients. The ERCP environment was simulated for the biliary phantom experiment to create a navigation system, which was further tested in patients. In addition, based on the estimation of the patient's respiratory motion, preoperative 3D biliary imaging from computed tomography of 18 patients with cholelithiasis was registered and fused in real-time with 2D fluoroscopic sequence generated by the C-arm unit during ERCP. RESULTS: Continuous image-guided ERCP was applied in the biliary phantom with a registration error of 0.46 mm ± 0.13 mm and a tracking error of 0.64 mm ± 0.24 mm. After estimating the respiratory motion, 3D/2D registration accurately transformed preoperative 3D biliary images to each image in the X-ray image sequence in real-time in 18 patients, with an average fusion rate of 88%. CONCLUSION: Continuous image-guided ERCP may be an effective approach to assist the operator and reduce the use of X-ray and contrast agents.

Clinical value of fluorescent cholangiography for the infraportal type of right posterior bile duct.

BACKGROUND: The infraportal type of the right posterior bile duct (infraportal RPBD) is a well-known anatomical variation that increases the potential risk of intraoperative biliary injury. The aim of this study is to clarify the clinical value of fluorescent cholangiography during single-incision laparoscopic cholecystectomy (SILC) for patients with infraportal RPBD. MATERIAL AND METHODS: Our procedure for SILC utilized the SILS-Port, and another 5-mm forceps was inserted via an umbilical incision. A laparoscopic fluorescence imaging system developed by Karl Storz Endoskope was utilized for fluorescent cholangiography. Between July 2010 and March 2022, 41 patients with infraportal RPBD underwent SILC. We conducted retrospective reviews of patient data, focusing on the clinical value of fluorescent cholangiography. RESULTS: Thirty-one patients underwent fluorescent cholangiography during SILC, but the remaining ten did not. Only one patient who did not undergo fluorescent cholangiography developed an intraoperative biliary injury. The detectability of infraportal RPBD before and during the dissection of Calot's triangle was 16.1% and 45.2%, respectively. These visible infraportal RPBDs were characterized as connections to the common bile duct. The confluence pattern of infraportal RPBD significantly influenced its detectability during the dissection of Calot's triangle (p < 0.001). CONCLUSIONS: The application of fluorescent cholangiography can lead to safe SILC, even for patients with infraportal RPBD. Its benefit is emphasized when infraportal RPBD is connected to the common bile duct.

Investigation of the optimal indocyanine green dose in real-time fluorescent cholangiography during laparoscopic cholecystectomy with an ultra-high-definition 4K fluorescent system: a randomized controlled trial.

This study aimed to investigate the indocyanine green (ICG) dose in real-time fluorescent cholangiography during laparoscopic cholecystectomy (LC) with a 4K fluorescent system. A randomized controlled clinical trial was conducted in patients who underwent LC for treatment of cholelithiasis. Using the OptoMedic 4K fluorescent endoscopic system, we compared four different doses of ICG (1, 10, 25, and 100 µg) administered intravenously within 30 min preoperatively and evaluated the fluorescence intensity (FI) of the common bile duct and liver background and the bile-to-liver ratio (BLR) of the FI at three timepoints: before surgical dissection of the cystohepatic triangle, before clipping the cystic duct, and before closure. Forty patients were randomized into four groups, and 33 patients were fully analyzed, with 10 patients in Group A (1 µg), 7 patients in Group B (10 µg), 9 patients in Group C (25 µg), and 7 patients in Group D (100 µg). The preoperative baseline characteristics were compared among groups (p > 0.05). Group A showed no or minimal FI in the bile duct and liver background, while Group D showed extremely high FIs in the bile duct and in the liver background at the three timepoints. Groups B and C presented with visible FI in the bile duct and low FI in the liver background. With increasing ICG doses, the FIs in the liver background and bile duct gradually increased at the three timepoints. The BLR, however, showed no increasing trend with an increasing ICG dose. A relatively high BLR on average was found in Group B, without a significant difference compared to the other groups (p > 0.05). An ICG dose ranging from 10 to 25 µg by intravenous administration within 30 min preoperatively was appropriate for real-time fluorescent cholangiography in LC with a 4K fluorescent system. Registration: This study was registered in the Chinese Clinical Trial Registry (ChiCTR No: ChiCTR2200064726).

Pancreaticobiliary maljunction induced cholangiocarcinoma after gallbladder cancer.

The essence of PBM is the premature confluence of bile duct and pancreatic duct, the mixture of bile and pancreatic juice leads to bile duct cyst, gallstone, gallbladder carcinoma, acute and chronic pancreatitis, etc, and the diagnostic mainly depends on imaging, anatomical examination and bile hyperamylase.

Assessment of a novel biliary-specific near-infrared fluorescent dye (BL-760) for intraoperative detection of bile ducts and biliary leaks during hepatectomy in a preclinical swine model.

OBJECTIVES: Postoperative bile leakage is a common complication of hepatobiliary surgery and frequently requires procedural intervention. Bile-label 760 (BL-760), a novel near-infrared dye, has emerged as a promising tool for identifying biliary structures and leakage, owing to its rapid excretion and strong bile specificity. This study aimed to assess the intraoperative detection of biliary leakage using intravenously administered BL-760 compared with intravenous (IV) and intraductal (ID) indocyanine green (ICG). MATERIALS AND METHODS: Laparotomy and segmental hepatectomy with vascular control were performed on two 25-30 kg pigs. ID ICG, IV ICG, and IV BL-760 were administered separately, followed by an examination of the liver parenchyma, cut liver edge, and extrahepatic bile ducts for areas of leakage. The duration of intra- and extrahepatic fluorescence detection was assessed, and the target-to-background (TBR) of the bile ducts to the liver parenchyma was quantitatively measured. RESULTS: In Animal 1, after intraoperative BL-760 injection, three areas of leaking bile were identified within 5 min on the cut liver edge with a TBR of 2.5-3.8 that was not apparent to the naked eye. In contrast, after IV ICG administration, the background parenchymal signal and bleeding obscured the areas of bile leakage. A second dose of BL-760 demonstrated the utility of repeated injections, confirming two of the three previously visualized areas of bile leakage and revealing one previously unseen leak. In Animal 2, neither ID ICG nor IV BL-760 injections showed obvious areas of bile leakage. However, fluorescence signals were observed within the superficial intrahepatic bile ducts after both injections. CONCLUSIONS: BL-760 enables the rapid intraoperative visualization of small biliary structures and leaks, with the benefits of fast excretion, repeatable intravenous administration, and high-fluorescence TBR in the liver parenchyma. Potential applications include the identification of bile flow in the portal plate, biliary leak or duct injury, and postoperative monitoring of drain output. A thorough assessment of the intraoperative biliary anatomy could limit the need for postoperative drain placement, a possible contributor to severe complications and postoperative bile leak.