UNASSIGNED: It is still a challenging problem for clinicians to explore the nature of the indeterminate biliary strictures (IBSs). Approximately 20% of biliary strictures remain undetermined after a thorough preoperative assessment.
UNASSIGNED: Here, we present two cases of indeterminate biliary strictures patients, whose cross- sectional imaging and endoscopic examination were nondiagnostic. The patients underwent exploratory laparotomy finally and were confirmed as malignancy. We also reviewed the recent reports in literatures regarding the evaluation of IBSs.
UNASSIGNED: Given the majority of the biliary strictures are malignancy, preoperative differentiation between benign and malignant is critical for choosing the best therapeutic regimen. Thus, close follow-up, multiple multidisciplinary discussion, and prompt surgical exploration are necessary for some difficult diagnostic cases.

Cholangiocarcinoma (CCA) is a rare cancer originating from the biliary epithelium and accounts for about 3% of all gastrointestinal malignancies. Unfortunately, the majority of patients are not eligible for surgical resection at the time of diagnosis, because of the locally advanced stage or metastatic disease. The overall survival time of unresectable CCA is generally less than 1 year, despite current chemotherapy regimens. Biliary drainage is often required as a palliative treatment for patients with unresectable CCA. Recurrent jaundice and cholangitis tend to occur because of reobstruction of the biliary stents. This not only jeopardizes the efficacy of chemotherapy, but also causes significant morbidity and mortality. Effective control of tumor growth is crucial for prolonging stent patency and consequently patient survival. Recently, endobiliary radiofrequency ablation (ERFA) has been experimented as a treatment modality to reduce tumor mass, and delay tumor growth, extending stent patency. Ablation is accomplished by means of high-frequency alternating current which is released from the active electrode of an endobiliary probe placed in a biliary stricture. It has been shown that tumor necrosis releases intracellular particles which are highly immunogenic and activate antigen-presenting cells, enhancing local immunity directed against the tumor. This immunogenic response could potentially enhance tumor suppression and be responsible for improved survival of patients with unresectable CCA who undergo ERFA. Several studies have demonstrated that ERFA is associated with an increased median survival of approximately 6 months in patients with unresectable CCA. Furthermore, recent data support the hypothesis that ERFA could ameliorate the efficacy of chemotherapy administered to patients with unresectable CCA, without increasing the risk of complications. This narrative review discusses the results of the studies published in recent years and focuses on the impact that ERFA could have on overall survival of patients with unresectable cholangiocarcinoma.

UNASSIGNED: Artificial intelligence (AI), when applied to computer vision using a convolutional neural network (CNN), is a promising tool in \"difficult-to-diagnose\" conditions such as malignant biliary strictures and cholangiocarcinoma (CCA). The aim of this systematic review is to summarize and review the available data on the diagnostic utility of endoscopic AI-based imaging for malignant biliary strictures and CCA.
UNASSIGNED: In this systematic review, PubMed, Scopus and Web of Science databases were reviewed for studies published from January 2000 to June 2022. Extracted data included type of endoscopic imaging modality, AI classifiers, and performance measures.
UNASSIGNED: The search yielded 5 studies involving 1465 patients. Of the 5 included studies, 4 (n=934; 3,775,819 images) used CNN in combination with cholangioscopy, while one study (n=531; 13,210 images) used CNN with endoscopic ultrasound (EUS). The average image processing speed of CNN with cholangioscopy was 7-15 msec per frame while that of CNN with EUS was 200-300 msec per frame. The highest performance metrics were observed with CNN-cholangioscopy (accuracy 94.9%, sensitivity 94.7%, and specificity 92.1%). CNN-EUS was associated with the greatest clinical performance application, providing station recognition and bile duct segmentation; thus reducing procedure length and providing real-time feedback to the endoscopist.
UNASSIGNED: Our results suggest that there is increasing evidence to support a role for AI in the diagnosis of malignant biliary strictures and CCA. CNN-based machine leaning of cholangioscopy images appears to be the most promising, while CNN-EUS has the best clinical performance application.

The specimen collection and subsequent pathological diagnosis of malignant biliary stricture (MBS) are difficult. This study aimed to determine whether the cell block (CB) method using overnight-stored bile is useful in the diagnosis of MBS. This trial was a single-arm prospective study involving a total of 59 patients with suspected MBS. The primary endpoint was cancer detectability and accuracy using the CB method, and a comparison with the detectability and accuracy achieved with bile cytology was made. The immunohistochemical sensitivity for maspin and p53 was also investigated in the CB and surgical specimens. We were able to collect bile from all 59 patients, and 45 of these patients were clinically diagnosed with MBS. The cancer detectability using the CB method (62.2%) was significantly higher than that using cytology (37.8%) (p = 0.0344). When CB was combined with biopsy, the rates of cancer detectability (75.6%) and accuracy (81.4%) increased. In eight patients who received surgical therapy, maspin- and p53-immunohistochemistry was applied to the surgical and CB specimens, and cancer cells in both specimens showed positive cytoplasmic and nuclear staining for maspin and nuclear staining for p53. The CB method is, thus, useful for detecting malignancy (UMIN000034707).

EUS-guided biliary drainage (EUS-BD) and percutaneous transhepatic cholangiography biliary drainage (PTC) are the two alternate methods for biliary decompression in cases where ERCP fails. We conducted a systematic review and meta-analysis of studies to compare the efficacy and safety of endoscopic and percutaneous biliary drainage for malignant biliary obstruction in patients with failed ERCP. A total of ten studies were included, fulfilling the inclusion criteria, including four retrospective studies and six randomized controlled trials. We compared the technical and clinical success rates and the acute, delayed, and total adverse events of EUS-BD with PTC. The odds ratios (ORs) and confidence intervals (CIs) were calculated. There was no difference between technical (OR: 0.47 [95% CI: 0.20-1.07]; P = 0.27) and clinical (OR: 2.24 [95% CI: 1.10-4.55]; P = 0.51) success rates between EUS-PD and PTC groups. Procedural adverse events (OR: 0.17 [95% CI: 0.09-0.31]; P = 0.03) and total adverse events (OR: 0.09 [95% CI: 0.02-0.38]; P < 0.01) were significantly different between the two groups; however, delayed adverse events were nonsignificantly different (OR: 0.73 [95% CI: 0.34-1.57]; P = 0.97). This meta-analysis indicates that endoscopic biliary drainage (EUS-BD) is equally effective but safer in terms of acute and total adverse events than percutaneous transhepatic biliary drainage (PTC) for biliary decompression in patients with malignant biliary strictures who have failed an ERCP.

Percutaneous biliary interventions are among the commonly performed nonvascular radiological interventions. Most common of these interventions is the percutaneous transhepatic biliary drainage for malignant biliary obstruction. Other biliary procedures performed include percutaneous cholecystostomy, biliary stenting, drainage for bile leaks, and various procedures like balloon dilatation, stenting, and large-bore catheter drainage for bilioenteric or post-transplant anastomotic strictures. Although these procedures are being performed for ages, no standard guidelines have been formulated. This article attempts at preparing guidelines for performing various percutaneous image-guided biliary procedures along with discussion on the published evidence in this field.

Biliary endoscopy is underutilized by interventional radiologists and has the potential to become an effective adjunctive tool to help both diagnose and treat a variety of biliary pathology. This is particularly true in cases where endoscopic retrograde cholangiopancreatography fails or is not feasible due to surgically altered anatomy. Both preoperative clinical and technical procedural factors must be taken into consideration prior to intervention. In this article, clinical evaluation, perioperative management, and procedural techniques for percutaneous biliary endoscopy are reviewed.

Percutaneous endoscopy operated by interventional radiologists has the potential to become an effective tool to both help diagnose and treat benign and malignant biliary strictures. This is particularly true in cases where endoscopic retrograde cholangiopancreatography fails or is not feasible due to surgically-altered anatomy. Both preoperative clinical and technical procedural factors must be taken into consideration when pursuing percutaneous endoscopy. In this article, clinical evaluation, perioperative management, and procedural techniques for biliary endoscopy for benign and malignant strictures are reviewed.

OBJECTIVE: Increasing evidence has demonstrated that serum soluble B7H3(sB7-H3) is a useful tumor marker for cancer diagnosis and prognostic evaluations. Whether sB7-H3 expressed in the bile is related to the progression of malignant biliary strictures must be clarified.
METHODS: Bile sB7-H3 was obtained via endoscopic retrograde cholangiopancreatography (ERCP) from 323 patients suspected to have malignant biliary strictures and was detected using a B7H3 ELISA kit. Diagnostic value was compared among bile sB7-H3, CA19-9, CA12-5, and CEA and ERCP-based cytological/tissue examination. Additionally, the correlations between the bile sB7-H3 concentration and the clinical characteristics of malignant biliary strictures were studied.
RESULTS: The bile sB7-H3 levels of patients with malignant biliary strictures were significantly higher than those in patients with benign biliary strictures (P < 0.001). The AUC values of the receiver operating characteristic(ROC) curves for CA19-9, CA12-5 and CEA were 0.764, 0.475 and 0.399, respectively, which were significantly lower than that of sB7-H3 (0.878); the sensitivities of ERCP-based cytological and tissue examinations were 55.7% and 66.4%, respectively, which were far lower than that of bile sB7-H3(81.2%). A high level of sB7-H3 in patients with malignant biliary strictures was found to be correlated with vascular invasion(P < 0.001), lymph node metastasis(P < 0.001), distant metastasis (P < 0.001) and tumor-node-metastasis (TNM) stage(P = 0.01). The overall survival rate of the patients in the high sB7-H3 group was significantly lower than that of the patients in the low sB7-H3 group(P = 0.014).
CONCLUSIONS: Bile sB7-H3 could serve as a valuable biomarker for patients with malignant biliary strictures and high levels of bile sB7-H3 were associated with poor clinical outcomes.

Synchronous biliary and duodenal malignant obstruction is a challenging endoscopic scenario in patients affected with ampullary, peri-ampullary, and pancreatic head neoplasia. Surgical bypass is no longer the gold-standard therapy for these patients, as simultaneous endoscopic biliary and duodenal stenting is currently a feasible and widely used technique, with a high technical success in expert hands. In recent years, endoscopic ultrasonography (EUS) has evolved from a diagnostic to a therapeutic procedure, and is now increasingly used to guide biliary drainage, especially in cases of failed endoscopic retrograde cholangiopancreatography (ERCP). The advent of lumen-apposing metal stents (LAMS) has expanded EUS therapeutic options, and changed the management of synchronous bilioduodenal stenosis. The most recent literature regarding endoscopic treatments for synchronous biliary and duodenal malignant stenosis has been reviewed to determine the best endoscopic approach, also considering the advent of an interventional EUS approach using LAMS.