The Role of Peroral Cholangioscopy in Evaluating Indeterminate Biliary Strictures

Efficacy and Safety of a Novel Tapered-Tip Sheath System for Biliary-Lesion Tissue Sampling: A Randomized Controlled Trial

Background/Aims

Pathological evaluation is crucial for diagnosing biliary lesions and determining appropriate treatment strategies. However, tissue sampling via the transpapillary route can be difficult. In this study, we aimed to assess the efficacy and safety of a novel tapered-tip sheath system for tissue sampling from biliary strictures.

Methods

This single-center, randomized, parallel-group clinical trial included patients aged 20 to 85 years admitted to Kyoto University Hospital for biliary strictures. The patients were randomly assigned (1:1) to a new or conventional method group. The primary outcome was technical success of biopsy at the target bile duct using the assigned method, as determined in accordance with the intention-to-treat principle. Adverse events were assessed in all eligible patients.

Results

Fifty-six patients were assessed for eligibility between September 2020 and March 2023; 50 patients were enrolled. The patients were randomly divided into the new (n=25) method group and the conventional (n=25) method group. Technical success was achieved in 96.0% (24/25) and 48.0% (12/25) of patients in the new and conventional method groups, respectively (risk ratio, 2.00; 95% confidence interval [CI], 1.32 to 3.03; risk difference, 48.0%; 95% CI, 27.0% to 69.0%; p<0.001). Adverse events occurred in 4.0% (1/25) and 36.0% (9/25) of patients in the new and conventional method groups, respectively (risk ratio, 0.11; 95% CI, 0.02 to 0.81; risk difference, -32.0%; 95% CI, -52.3% to -11.7%; p=0.005).

Conclusions

The novel tapered-tip sheath system is a promising option for precisely and safely delivering biopsy forceps to target sites, thereby facilitating the diagnosis of biliary strictures.

The past, present, and future of endoscopic management for biliary strictures: technological innovations and stent advancements

Biliary stricture can be induced by intrinsic narrowing and extrinsic compression, with the majority of cases being malignant. Clinically, distinguishing between benign and malignant biliary strictures remains a considerable challenge, and the ongoing disagreement over the optimal choice of biliary stents significantly influences treatment strategies and impacts patients' survival and prognosis. The utilization and advancement of endoscopic techniques have heightened the diagnostic sensitivity for biliary strictures. Concurrently, innovative technologies such as endoscopic ultrasound and magnetic compression anastomosis emerge as viable alternatives when endoscopic retrograde cholangiopancreatography (ERCP) is not an option, providing fresh insights for the clinical management of these patients. Traditional plastic and metal stents, characterized by their complex application and limited scope, have been unable to fully satisfy clinical needs. The introduction of novel stent varieties has notably improved this scenario, marking a considerable progression towards precision medicine. However, the clinical validation of the diverse stent materials available is incomplete. Hence, a thorough discussion on the present state and evolving trends of biliary stents is warranted.

Direct Single-Operator Cholangioscopy and Intraductal Ultrasonography in Patients with Indeterminate Biliary Strictures: A Single Center Experience

The evaluation of biliary strictures poses a challenge due to the low sensitivity of standard diagnostic approaches, but the advent of direct single-operator cholangioscopy (DSOC) has revolutionized this paradigm. Our study aimed to assess the diagnostic performance of DSOC and DSOC-targeted biopsies, intraductal ultrasound (IDUS), and standard brush cytology in patients with indeterminate biliary strictures (IBS). We reviewed patients who underwent advanced diagnostic evaluation for IBS at our endoscopy unit from January 2018 to December 2022, all of whom had previously undergone at least one endoscopic attempt to characterize the biliary stricture. Final diagnoses were established based on surgical pathology and/or clinical and radiological follow-up spanning at least 12 months. A total of 57 patients, with a mean age of 67.2 ± 10.0 years, were included, with a mean follow-up of 18.2 ± 18.1 months. The majority of IBS were located in the distal common bile duct (45.6%), with malignancy confirmed in 35 patients (61.4%). DSOC and IDUS demonstrated significantly higher accuracies (89.5% and 82.7%, respectively) compared to standard cytology (61.5%, p < 0.05). Both DSOC visualization and IDUS exhibited optimal diagnostic yields in differentiating IBS with an acceptable safety profile.

Disposable Gastrointestinal Scopes: A Systematic Review

OBJECTIVE

Endoscopes are an essential tool in the diagnosis, screening, and treatment of gastrointestinal diseases. In 2019, the Food and Drug Administration issued a news release, recommending that duodenoscope manufacturers and health care facilities phase out fully reusable duodenoscopes with fixed endcaps in lieu of duodenoscopes that are either fully disposable or those that contain disposable endcaps. With this study, we systematically reviewed the published literature on single-use disposable gastrointestinal scopes to describe the current state of the literature and provide summary recommendations on the role of disposable gastrointestinal endoscopes.

MATERIALS AND METHODS

For our inclusion criteria, we searched for studies that were published in the year 2015 and afterward. We performed a literature search in PubMed using the keywords, "disposable," "reusable," "choledochoscope," "colonoscope," "duodenoscope," "esophagoscope," "gastroscope," and "sigmoidoscope." After our review, we identified our final article set, including 13 articles relating to disposable scopes, published from 2015 to 2023.

RESULTS

In this review, we show 13 articles discussing the infection rate, functionality, safety, and affordability of disposable gastrointestinal scopes in comparison to reusable gastrointestinal scopes. Of the 3 articles that discussed infection rates (by Forbes and colleagues, Ridtitid and colleagues, and Ofosu and colleagues), each demonstrated a decreased risk of infection in disposable gastrointestinal scopes. Functionality was another common theme among these articles. Six articles (by Muthusamy and colleagues, Bang and colleagues, Lisotti and colleagues, Ross and colleagues, Kang and colleagues, and Forbes and colleagues) demonstrated comparable functionality of disposable scopes to reusable scopes. The most reported functionality issue in disposable scopes was decreased camera resolution. Disposable scopes also showed comparable safety profiles compared with reusable scopes. Six articles (by Kalipershad and colleagues, Muthusamy and colleagues, Bang and colleagues, Lisotti and colleagues, Luo and colleagues, and Huynh and colleagues) showed comparable rates of AEs, whereas 1 article (by Ofosu and colleagues) demonstrated increased rates of AEs with disposable scopes. Lastly, a cost analysis was looked at in 3 of the articles. Two articles (by Larsen et al and Ross and colleagues) remarked that further research is needed to understand the cost of disposable scopes, whereas 1 article (by Kang and colleagues) showed a favorable cost analysis.

CONCLUSIONS

After a review of the literature published since the 2015 Food and Drug Administration safety communication, disposable scopes have been shown to be effective in decreasing infection risks while maintaining similar safety profiles to conventional reusable scopes. However, more research is required to compare disposable and reusable scopes in terms of functionality and cost-effectiveness.

Accurate and safe diagnosis and treatment of neoplastic biliary lesions using a novel 9F and 11F digital single-operator cholangioscope

Background and study aims Digital single-operator cholangioscopy (DSOC) allows the diagnosis of biliary duct disorders and treatment for complicated stones. However, these technologies have limitations such as the size of the probe and working channel, excessive cost, and low image resolution. Recently, a novel DSOC system (eyeMAX, Micro-Tech, Nanjing, China) was developed to address these limitations. We aimed to evaluate the usefulness and safety of a novel 9F and 11F DSOC system in terms of neoplastic diagnostic accuracy based on visual examination, ability to evaluate tumor extension and to achieve complete biliary stone clearance, and procedure-related adverse events (AEs). Patients and methods Data from ≥ 18-year-old patients who underwent DSOC from July 2021 to April 2022 were retrospectively recovered and divided into a diagnostic and a therapeutic cohort. Results A total of 80 patients were included. In the diagnostic cohort (n = 49/80), neovascularity was identified in 26 of 49 patients (46.9%). Biopsy was performed in 65.3% patients with adequate tissue sample obtained in 96.8% of cases. Biopsy confirmed neoplasia in 23 of 32 cases. DSOC visual impression achieved 91.6% sensitivity and 87.5% specificity in diagnosing neoplasms. In the therapeutic cohort (n = 43/80), 26 of 43 patients required lithotripsy alone. Total stone removal was achieved in 71% patients in the first session. Neither early nor late AEs were documented in either the diagnostic or therapeutic cohort. Conclusions The novel DSOC device has excellent diagnostic accuracy in distinguishing neoplastic biliary lesions as well as therapeutic benefits in the context of total stone removal, with no documented AEs.

Use of catheter-based cholangioscopy in the diagnosis of indeterminate stenosis: a multicenter experience

BACKGROUND

Direct bile ducts visualization through cholangioscopy has gained popularity due to its better diagnostic accuracy than a standard ERCP in indeterminate biliary stricture.

METHODS

We aimed to review our catheter-based cholangioscopy interventions in patients with indeterminate biliary stenosis, using the SpyGlass Direct Visualization System (SDVS) and summarize our experience in terms of procedures and results. We collected 25 consecutive patients with indeterminate biliary stricture over 3 years.

RESULTS

The overall procedural success in our cohort amounted to 96% (24/25). If we focus on the diagnostic procedures, the ability to merely visualize the region of interest/lesion and perform biopsy of the lesion was possible in 96% (24/25) In our cohort localization in the common bile duct (P=0.03; 95% CI: 0.27-0.96) was found as positive determining factor for diagnosis. Sensitivity, specificity and accuracy for visual diagnosis by SDVS in our cohort were 100, 83.3 and 96%, respectively. The use of biopsy or obtaining a histological diagnosis to assist in identifying patients with malignant stenosis, to exclude malignancy and to correctly classify diagnosed patients resulted in a sensitivity of 100%, a specificity of 73% with an overall accuracy of 94.4%. Only a mild adverse event (cholangitis, treated conservatively) occurred.

CONCLUSIONS

Today, the SDVS should be considered essential in diagnosing indeterminate biliary strictures, since the procedure is associated with high procedural success in terms of diagnostic accuracy, alters clinical outcome in over 80% of considered insolvable cases, with an acceptable safety profile.

Endoscopic Management of Difficult Biliary Stones: An Evergreen Issue

Choledocholithiasis is one of the most common indications for endoscopic retrograde cholangiopancreatography (ERCP) in daily practice. Although the majority of stones are small and can be easily removed in a single endoscopy session, approximately 10-15% of patients have complex biliary stones, requiring additional procedures for an optimum clinical outcome. A plethora of endoscopic methods is available for the removal of difficult biliary stones, including papillary large balloon dilation, mechanical lithotripsy, and electrohydraulic and laser lithotripsy. In-depth knowledge of these techniques and the emerging literature on them is required to yield the most optimal therapeutic effects. This narrative review aims to describe the definition of difficult bile duct stones based on certain characteristics and streamline their endoscopic retrieval using various modalities to achieve higher clearance rates.

Endoscopic Diagnosis of Extra-Luminal Cancers

The last 2 decades have seen an emergence of endoscopic technologies and techniques allowing for minimally invasive modalities for assessing and sampling lesions outside of the gastrointestinal lumen, including the chest, abdomen, and pelvis. Incorporating these new endoscopic approaches has revolutionized the diagnosis and staging of extra-luminal malignancies and has enabled more accessible and safer tissue acquisition.

A novel peroral digital cholangioscope with a large accessory channel: An experimental study

BACKGROUND/PURPOSE

A peroral cholangioscope (POCS) can allow direct visualization of the biliary mucosa and its use is becoming more widespread due to improvements in functionality, image quality, and operability, as well as the development of related devices. Recently, a novel mother-baby peroral cholangioscope (nMB-POCS) with a large (2-mm) accessory channel has been developed. In this study, we evaluated the feasibility of this novel POCS in a dry simulation and animal model.

METHODS

We evaluated the ease of insertion and maneuverability of the nMB-POCS, the image quality, and the passage of the devices into the accessory channel and into the common bile duct in a dry and live porcine model.

RESULTS

In both models, the nMB-POCS could be easily inserted into the duodenoscope and into the distal bile duct and hilum. The image quality was good, and it was possible to observe the surface structure and the vascular network of the bile duct mucosa in detail.

CONCLUSIONS

The nMB-POCS with its larger accessory channel is expected to improve the efficiency of diagnosis and  treatment, and reduce the procedure time. Clinical studies in patients are warranted.

Efficacy and safety of direct peroral cholangioscopy using a new multibending ultra-slim endoscope for the management of biliary diseases

BACKGROUND/PURPOSE

Compared with currently available duodenoscopy-assisted systems, direct peroral cholangioscopy (DPOC) using an ultra-slim endoscope is limited by technical difficulties. The multibending (MB) ultra-slim endoscope was introduced as a dedicated cholangioscope for DPOC to challenge the technical problem. We retrospectively analyzed the clinical utility of DPOC using an MB endoscope with free-hand insertion into the bile duct in patients with biliary diseases.

METHODS

A total of 145 patients who underwent DPOC using an MB endoscope were analyzed. The primary outcome was the technical success rate of DPOC using the free-hand insertion of the MB endoscope. The secondary outcomes were the technical success rates of DPOC-guided diagnostic and therapeutic interventions, the diagnostic accuracy of DPOC-guided target biopsy, and adverse events related to DPOC.

RESULTS

Free-hand biliary insertion of a MB endoscope for DPOC was technically successful in 133 patients (91.7%). DPOC-guided target biopsy was successful in 36 of 38 patients (94.7%) and had a diagnostic accuracy of 91.7% (95% confidence interval, 82.6-100). Sixty-nine therapeutic interventions were performed; technical success was achieved in 65 (94.2%). No severe adverse events were observed.

CONCLUSIONS

The MB ultra-slim endoscope was technically effective to perform a DPOC including various diagnosis and therapeutic interventions without device assistance. MB endoscope is considered to contribute to expanding a role of DPOC in diagnosis and treatment of diverse biliary tract diseases.

Digital Cholangioscopic Interpretation: When North Meets the South

BACKGROUND

Digital single-operator cholangioscopy (DSOC) (SpyGlass DS™, Boston Scientific, MA, USA) allows for high-definition imaging of the biliary tree. The superior visualization has led to the development of two different sets of criteria to evaluate and classify indeterminate biliary strictures: the Monaco criteria and the criteria in Carlos Robles-Medranda's publication (CRM). Our objective was to assess the interrater agreement (IA) of DSOC interpretation for indeterminate biliary strictures using the two newly published criteria.

METHODS

Forty de-identified DSOC video recordings were sent to 15 interventional endoscopists with experience in cholangioscopy. They were asked to score the videos based on the presence of Monaco Classification criteria: stricture, lesion, mucosal changes, papillary projections, ulceration, white linear bands or rings, and vessels. Next, they scored the videos using CRM criteria: villous pattern, polypoid pattern, inflammatory pattern, flat pattern, ulcerate pattern and honeycomb pattern. The endoscopists then diagnosed the recordings as neoplastic or non-neoplastic based on the criteria. Intraclass correlation (ICC) analysis was done to evaluate interrater agreement for both criteria set and final diagnosis.

RESULTS

Recordings of 26 malignant lesions and 14 benign lesions were scored. The IA using both the Monaco criteria and CRM criteria ranged from poor to excellent (range 0.1-0.76) and (range 0.1-0.62), respectively. Within the Monaco criteria, IA was excellent for lesion (0.75) and fingerlike papillary projections (0.74); good for tortuous vessels (0.7), mucosal features (0.62), uniform papillary projections (0.53), and ulceration (0.58); and fair for white linear bands (0.4). Within the CRM criteria, the IA was good for villous pattern (0.62), flat pattern (0.62), and honeycomb pattern; fair for ulcerated pattern (0.56), polypoid pattern (0.52) and inflammatory pattern (0.54). The diagnostic IA using Monaco criteria was good (0.65), while the diagnostic IA using CRM was fair (0.58). The overall diagnostic accuracy using the Monaco classification was 61% and CRM criteria were 57%.

CONCLUSION

The IOA and accuracy rate of DSOC using visual criteria from both Monaco Criteria and CRM are similar. However, some criteria from both sets suffer from poor IA, thus affecting the overall diagnostic accuracy. More formal training and refinements in visual criteria with additional validation are needed to improve diagnostic accuracy.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02166099.

Improving Diagnostic Yield in Indeterminate Biliary Strictures

Indeterminate biliary strictures are defined as a narrowing of the bile duct that cannot be differentiated as malignant or benign after performing cross-sectional imaging and an ERCP. Identifying the etiology of a bile duct stricture is the single most important step in determining whether a complex and potentially morbid surgical resection is warranted. Due to this diagnostic and therapeutic dilemma, new technologies, laboratory tests, and procedures are emerging to solve this problem.

Choledochoscopy: An update

Choledochoscopy, or cholangioscopy, is an endoscopic procedure for direct visualization within the biliary tract for diagnostic or therapeutic purposes. Since its conception in 1879, many variations and improvements are made to ensure relevance in diagnosing and managing a range of intrahepatic and extrahepatic biliary pathologies. This ranges from improved visual impression and optical guided biopsies of indeterminate biliary strictures and clinically indistinguishable pathologies to therapeutic uses in stone fragmentation and other ablative therapies. Furthermore, with the evolving understanding of biliary disorders, there are significant innovative ideas and techniques to fill this void, such as nuanced instances of biliary stenting and retrieving migrated ductal stents. With this in mind, we present a review of the current advancements in choledo-choscopy with new supporting evidence that further delineates the role of choledochoscopy in various diagnostic and therapeutic interventions, complications, limitations and put forth areas for further study.

Diagnostic accuracy and interobserver agreement of digital single-operator cholangioscopy for indeterminate biliary strictures

BACKGROUND AND AIMS

Digital single-operator cholangioscopy (d-SOC) with cholangioscopic biopsy sampling has shown promise in the evaluation of indeterminate biliary strictures. Some studies have suggested higher sensitivity for visual impression compared with biopsy sampling, although assessors were not blinded to previous investigations. We aimed to investigate the diagnostic accuracy and interobserver agreement (IOA) of d-SOC in the visual appraisal of biliary strictures when blinded to additional information.

METHODS

A multicenter, international cohort study was performed. Cholangioscopic videos in patients with a known final diagnosis were systematically scored. Pseudonymized videos were reviewed by 19 experts in 2 steps: blinded for patient history and investigations and unblinded.

RESULTS

Forty-four high-quality videos were reviewed of 19 benign and 25 malignant strictures. The sensitivity and specificity for the diagnosis of malignancy was 74.2% and 46.9% (blinded) and 72.7% and 62.5% (unblinded). Cholangioscopic certainty of a malignant diagnosis led to overdiagnosis (sensitivity, 90.6%; specificity, 33%), especially if no additional information was provided. The IOA for the presence of malignancy was fair for both assessments (Fleiss' κ = .245 [blinded] and κ = .321 [unblended]). For individual visual features, the IOA ranged from slight to moderate for both assessments (κ = .059-.400 vs κ = .031-.452).

CONCLUSIONS

This study showed low sensitivity and specificity for blinded and unblinded d-SOC video appraisal of indeterminate biliary strictures, with considerable interobserver variation. Although reaching a consensus on the optical features of biliary strictures remains important, optimizing visually directed biopsy sampling may be the most important role of cholangioscopy in biliary stricture assessment.

Next-generation sequencing in the evaluation of biliary strictures in patients with primary sclerosing cholangitis

BACKGROUND

Primary sclerosing cholangitis (PSC) is a well-described risk factor for the development of cholangiocarcinoma (CCA). Early detection of CCA in these patients is of great importance because it expands options for therapeutic interventions, including liver transplantation. Current diagnostic tests for the evaluation of biliary strictures are limited to biliary brushing (BB) cytology and fluorescence in situ hybridization (FISH). Next-generation sequencing (NGS) has become an important diagnostic tool in oncology and may be a useful tool for diagnosing CCA on BBs. It is not clear how NGS performs when it is added to BB cytology and FISH in patients with PSC.

METHODS

This study reports the authors' experience with NGS performed as a prospective cotest with cytology and FISH on BBs obtained from 60 patients with PSC followed at Massachusetts General Hospital. A duct with malignancy was defined as a high-risk (HR) stricture with either high-grade dysplasia or CCA.

RESULTS

NGS was better than FISH and cytology in detecting HR strictures, which showed multiple genetic mutations in all cases. NGS provided specific mutational information, and NGS results were reproducible in longitudinal samples.

CONCLUSIONS

Adding NGS to BB cytology and FISH in the evaluation of biliary strictures for patients with PSC may provide additional information that could help to inform clinical management.

Comparison of EUS and ERCP-guided tissue sampling in suspected biliary stricture

Background

Endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic ultrasound (EUS) are commonly used diagnostic modalities in biliary strictures. We compared the diagnostic yield of EUS and ERCP-based tissue sampling in intrinsic biliary strictures without extrinsic mass outside the bile duct.

Methods

A total of 85 patients who underwent ERCP and EUS for diagnosis of suspected biliary strictures confined to the bile duct were analyzed retrospectively at Samsung Medical Center, Seoul, Korea, between 2010 and 2018.

Results

Seventy-one patients were diagnosed with malignancy and 14 patients were diagnosed with benign strictures. EUS-based tissue sampling was more sensitive and accurate than ERCP-based tissue sampling (p = 0.038). The overall sensitivity and accuracy were 67.6% (95% confidence interval (CI) 56.1–77.3) and 72.9% (95% CI 62.7–81.2) for ERCP-based sampling, and 80.3% (95% CI 69.6–87.9) and 83.5% (95% CI 74.2–89.9) for EUS-based sampling, respectively. EUS-based sampling was superior to ERCP-based sampling in distal bile duct strictures (accuracy: 87.0% vs. 72.5%, p = 0.007), but not in perihilar strictures. In cases without intraductal mass, EUS-based tissue sampling was also superior to ERCP-based sampling (accuracy: 83.3% vs. 69.7%, p = 0.029), but not in cases with mass.

Conclusion

EUS-based tissue sampling was superior to ERCP-based method in intrinsic biliary stricture with no mass outside the bile duct, particularly in those without intraductal mass or those with strictures located in distal bile duct. Therefore, EUS-based sampling should be considered for making a pathological diagnosis of suspected distal bile duct strictures even in lesions without definite mass.

Biliary Strictures and Cholangiocarcinoma - Untangling a Diagnostic Conundrum

Cholangiocarcinoma is an uncommon and highly aggressive biliary tract malignancy with few manifestations until late disease stages. Diagnosis is currently achieved through a combination of clinical, biochemical, radiological and histological techniques. A number of reported cancer biomarkers have the potential to be incorporated into diagnostic pathways, but all lack sufficient sensitivity and specificity limiting their possible use in screening and early diagnosis. The limitations of standard serum markers such as CA19-9, CA125 and CEA have driven researchers to identify multiple novel biomarkers, yet their clinical translation has been slow with a general requirement for further validation in larger patient cohorts. We review recent advances in the diagnostic pathway for suspected CCA as well as emerging diagnostic biomarkers for early detection, with a particular focus on non-invasive approaches.

[Influence of molecular pathology on oncological surgery of liver and bile duct tumors]

BACKGROUND

Molecular pathology is increasingly being used to guide treatment in oncology. Approximately 25% of all hepatocellular carcinomas (HCC) and 50% of cholangiocarcinomas (CCA) present with known cancer-relevant mutations; however, the impact of the mutations on the treatment of these tumors is not yet sufficiently understood.

PURPOSE

To evaluate the current literature on molecular pathological advances in HCC/CCA and the potential impact on oncological surgery.

MATERIAL AND METHODS

A comprehensive search of the available literature on currently known molecular biomarkers in HCC/CCA was performed in PubMed and clinitrials.gov. Following review, the potential impact of these biomarkers on oncological surgery was analyzed and is discussed.

CONCLUSION

Molecular pathological investigations can be used to support the classification of tumors and to determine the dignity of HCC/CCA. Predictive molecular biomarkers are not yet established in routine diagnostics but can be used to individualize advanced oncological treatment.

Editors' Choice of Noteworthy Clinical Endoscopy Publications in the First Decade

This is a special review to celebrate the 10^th anniversary of Clinical Endoscopy. Each deputy editor has selected articles from one’s subspecialty that are significant in terms of the number of downloads, citations, and clinical importance. The articles included original articles, review articles, systematic reviews, and meta-analyses.

Diagnostic performance of digital and video cholangioscopes in patients with suspected malignant biliary strictures: a systematic review and meta-analysis

BACKGROUND

Per-oral cholangioscopy (POC) has evolved over the past decade from fiberoptic to digital and video imaging systems. Nowadays, only direct per-oral cholangioscopy (DPOC) and digital single-operator cholangioscopy (DS) are performed in daily practice. With better image resolution, POC is increasingly used as diagnostic tools in patients with suspected malignant biliary stricture (MBS). We aimed to evaluate the diagnostic yield of digital/video cholangioscopes for the diagnosis of MBS.

METHODS

A systematic search was performed in MEDLINE, Embase, and ISI Web of Knowledge databases until April 2020, to identify randomized controlled trials and prospective studies using digital or video POC. The meta-analysis of diagnostic accuracy study was performed to calculate summary estimates of the primary outcomes, including pooled sensitivity, and specificity of POC to diagnose MBS using bivariate random-effects models. Tissue histopathology was used as the reference standard for MBS diagnosis. For benign stricture, negative tissue histopathology and at least 6 months clinical follow-up were required.

RESULTS

Thirteen original articles with 876 patients were identified. The overall pooled sensitivity and specificity were 88 (95% CI 83-91) and 95 (95% CI 89-98), respectively. The area under the curve (AUROC) was 0.94 (95% CI 0.92-0.96). Subgroup analysis showed that cholangioscopic image impression provided significantly higher sensitivity (93% (95% CI 88-96) vs 82% (95% CI 76-87); p = 0.007), but lower specificity 86% (95% CI 75-92) vs 98 (95% CI 95-99); p < 0.001) than the tissue diagnosis from cholangioscopic-guided biopsy. In addition, biopsy obtained from DPOC had significantly higher sensitivity than that of DS (92% (95% CI 81-97) vs 79% (95% CI 72-84); p = 0.004). Diagnostic performance under image-enhanced endoscopy was not significantly better from white light endoscopy.

CONCLUSIONS

Digital/video POC has very high diagnostic performance to diagnose MBS. While image diagnosis provides higher sensitivity than biopsy, its specificity drops as a trade-off.

Diagnostic Approach to Suspected Perihilar Malignancy

Background

Cholangiocarcinomas are relatively rare tumors most frequently arising from the epithelium of the hilar bile ducts. The diagnosis is often made in advanced (symptomatic) stages, which accounts for the infavorable prognosis with a 5-year survival of less than 10%. Identification of perihilar cholangiocarcinoma (pCCA) is often challenging because there is no single method offering sufficient diagnostic accuracy.

Summary

Most tumors arise in patients without specific risk factors. Clinical symptoms of pCCA are nonspecific and reliable biomarkers are lacking, with carbohydrate antigen 19-9 being the most commonly used tumor marker (but with a low accuracy). Cross-sectional imaging (CT and MRI) is used to identify and map hilar strictures and determine resectability by showing vascular involvement. Endoscopic ultrasound offers additional information on locoregional tumor spread and lymph node involvement. Endoscopic retrograde cholangiography in combination with cholangioscopy gives direct access to and imaging of hilar strictures but it does not always distinguish between pCCA and benign hilar strictures. Tissue acquisition for histological diagnosis is challenging, with frequent sampling errors regardless of the method of biopsy procurement because of the cellular paucity of tumor tissue.

Key Messages

In suspected perihilar malignancy, a mosaic of clinical data has to be taken into account. Histological evaluation of (endoscopically harvested) specimens is pivotal to differential diagnosis. Several new techniques to increase diagnostic accuracy are under investigation (biomarkers and genetic testing among others).

Digital Image Analysis has an Additive Beneficial Role to Conventional Cytology in Diagnosing the Nature of Biliary Ducts Stricture

BACKGROUND & AIM

Conventional cytological evaluation (CCE) fails to identify nature indeterminate biliary duct stricture (IBDS) in many cases. Digital image analysis (DIA) has the ability to identify and analyze the DNA content of cells. This study assesses the role of DIA in recognizing the nature of IBDS compared to CCE.

METHODS

A prospective observational study was conducted at the Al-Rajhi University Hospital. Fifty patients with IBDS, based on abdominal imaging, were subjected to endoscopic retrograde cholangiopancreatography (ERCP) and brush sampling. These samples were evaluated with CCE and DIA. Follow-up for at least 9 months and cost-analysis had also been done.

RESULTS

Based on the final diagnosis, 32 (64.0%) patients had malignant stricture, and 39 (78.0%) had distal stricture. DIA had 84.40% (95% CI; 67.20-94.70) sensitivity and 94.40% (95% CI; 72.70-99.90) specificity in identifying nature of IBDS, whereas CCE had 19.0% (95% CI; 7.20-36.40) sensitivity and 89.0% (95% CI; 65.30-98.60) specificity. Combination of both modalities had 84.40% (95% CI; 67.20-94.70) sensitivity and 83.30% (95% CI; 58.60-96.40) specificity in identification nature of IBDS. Based on CCE alone, only 6/32 (18.80%) of malignant stricture were diagnosed, and 26/32 (81.20%) were missed. However, DIA alone was able to diagnose 27/32 (84.40%) of malignant stricture, and only 5 cases were missed. Both procedures had detection rate of malignant stricture as DIA alone. Benign stricture was correctly diagnosed in 16/18 (88.80%), 17/18 (94.40%), and 15/18 (83.30%) using CCE alone, DIA alone, and both procedures together, respectively. Cost per detection additional one malignant stricture using DIA required 99.4$.

CONCLUSION

DIA is substantially better than CCE in diagnosing the nature of IBDS but at an increase cost and thus suggests its application in a wider role in clinical practice.

CLINICAL TRIAL NUMBER

NCT04112030.

Artificial intelligence in pancreaticobiliary endoscopy

Artificial intelligence (AI) applications in health care have exponentially increased in recent years, and a few of these are related to pancreatobiliary disorders. AI-based methods were applied to extract information, in prognostication, to guide clinical treatment decisions and in pancreatobiliary endoscopy to characterize lesions. AI applications in endoscopy are expected to reduce inter-operator variability, improve the accuracy of diagnosis, and assist in therapeutic decision-making in real time. AI-based literature must however be interpreted with caution given the limited external validation. A multidisciplinary approach combining clinical and imaging or endoscopy data will better utilize AI-based technologies to further improve patient care.

Artificial intelligence in biliopancreatic endoscopy: Is there any role?

Artificial intelligence (AI) research in endoscopy is being translated at rapid pace with a number of approved devices now available for use in luminal endoscopy. However, the published literature for AI in biliopancreatic endoscopy is predominantly limited to early pre-clinical studies including applications for diagnostic EUS and patient risk stratification. Potential future use cases are highlighted in this manuscript including optical characterisation of strictures during cholangioscopy, prediction of post-ERCP acute pancreatitis and selective biliary duct cannulation difficulty, automated report generation and novel AI-based quality key performance metrics. To realise the full potential of AI and accelerate innovation, it is crucial that robust inter-disciplinary collaborations are formed between biliopancreatic endoscopists and AI researchers.

Determining the Indeterminate Biliary Stricture: Cholangioscopy and Beyond

PURPOSE OF REVIEW

Indeterminate biliary strictures (IDBS) continue to be an area of frustration for clinicians. Standard endoscopic retrograde cholangiopancreatography (ERCP) with conventional brush cytology and/or forceps biopsy has a low sensitivity for distinguishing benign from malignant biliary strictures. A delay in diagnosis of malignancy has consequences for subsequent therapy or surgery. In this article, we review current and emerging technologies that may aid in this diagnostic dilemma.

RECENT FINDINGS

Several technologies have been utilized in IDBS to establish a diagnosis which include peroral cholangioscopy, confocal laser endomicroscopy, endoscopic ultrasound with fine needle aspiration, intraductal ultrasound, optical coherence tomography, fluorescence in situ hybridization, next generation sequencing, integrated molecular pathology, and DNA-image cytometry. While cholangioscopy and confocal laser endomicroscopy have become standards of care in expert centers for the evaluation of patients with IDBS, there are several endoscopic and molecular modalities that may also aid in establishing a diagnosis. Further head-to-head prospective diagnostic studies as well as cost-efficacy studies are needed.

Endoscopic Management of Pancreaticobiliary Disease

The evolution of advanced pancreaticobiliary endoscopy in the past 50 years is remarkable. Endoscopic retrograde cholangiopancreatography (ERCP) has progressed from a diagnostic test to an almost entirely therapeutic procedure. The endoscopist must have a clear understanding of the indications for ERCP to avoid unnecessary complications, including post-ERCP pancreatitis. Endoscopic ultrasound initially was used as a diagnostic tool but now is equipped with accessary channels allowing endoscopic ultrasound-guided interventions in various pancreaticobiliary conditions. This review discusses the endoscopic management of common pancreatic and biliary diseases along with the techniques, indications, outcomes, and complications of pancreaticobiliary endoscopy.

Role of Peroral Cholangioscopy in the Diagnosis of Primary Sclerosing Cholangitis

Primary sclerosing cholangitis (PSC) is characterized by idiopathic biliary stricture followed by progressive cholestasis and fibrosis. When diagnosing PSC, its differentiation from other types of sclerosing cholangitis and cholangiocarcinoma is necessary. The cholangioscopic findings of PSC have not been investigated sufficiently. PSC and IgG4-related sclerosing cholangitis are difficult to distinguish by peroral cholangioscopy (POCS), but POCS is useful for excluding cholangiocarcinoma. POCS findings vary according to the condition and stage of disease. In the active phase, findings such as mucosal erythema, ulceration, fibrinous white exudate, and an irregular surface are observed and may reflect strong inflammation in the biliary epithelium. On the other hand, findings such as scarring, pseudodiverticula, and bile duct stenosis appear in the chronic phase and may reflect fibrosis and stenosis resulting from repeated inflammation. Observation of inside the bile duct by POCS might confirm the current PSC activity. Because POCS offers not only information regarding the diagnosis of PSC and PSC-associated cholangiocarcinoma but also the current statuses of biliary inflammation and stenosis, POCS could significantly contribute to the diagnosis and treatment of PSC once the characteristic findings of PSC are confirmed by future studies.

Efficacy of digital single-operator cholangioscopy in the visual interpretation of indeterminate biliary strictures: a systematic review and meta-analysis

OBJECTIVE

Indeterminate biliary strictures remain a significant diagnostic challenge. Digital single-operator cholangioscopy (D-SOC) incorporates digital imaging which enables higher resolution for better visualization and diagnosis of biliary pathology. We aimed to conduct a systematic review and meta-analysis of available literature in an attempt to determine the efficacy of D-SOC in the visual interpretation of indeterminate biliary strictures.

MATERIAL AND METHODS

Electronic searches were performed using Medline (PubMed), EMBASE, and Cochrane Library. All D-SOC studies that reported the diagnostic performance in visual interpretation of indeterminate biliary strictures and biliary malignancies were included. The Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 was used to evaluate the quality of the included studies. All data were extracted and pooled to construct a 2 × 2 table. The visual interpretation of D-SOC was compared to resected surgical specimens or clinical follow-up in the included patients. Pooled sensitivity, specificity, positive predictive value, negative predictive value, prevalence, positive likelihood ratio (+LR), negative likelihood ratio (-LR), and diagnostic odds ratio (OR) were calculated. The summarized receiver operating characteristic (SROC) curve corresponding with the area under the curve (AUC) was also analyzed.

RESULTS

The search yielded 465 citations. Of these, only six studies with a total of 283 procedures met inclusion criteria and were included in the meta-analysis. The overall pooled sensitivity and specificity of D-SOC in the visual interpretation of biliary malignancies was 94% (95% CI 89-97) and 95% (95%CI 90-98), respectively, while +LR, -LR, diagnostic OR, and AUC were 15.20 (95%CI 5.21-44.33), 0.08 (95%CI 0.04-0.14), 308.83 (95%CI 106.46-872.82), and 0.983, respectively. The heterogeneity among 6 included studies was moderate for specificity (I² = 0.51) and low for sensitivity (I² = 0.17) and diagnostic OR (I² = 0.00).

CONCLUSION

D-SOC is associated with high sensitivity and specificity in the visual interpretation of indeterminate biliary strictures and malignancies. D-SOC should be considered routinely in the diagnostic workup of indeterminate biliary lesions.

Early Diagnosis And Management Of Malignant Distal Biliary Obstruction: A Review On Current Recommendations And Guidelines

Malignant biliary obstruction is a challenging condition, requiring a multimodal approach for both diagnosis and treatment. Pancreatic adenocarcinoma and cholangiocarcinoma are the leading causes of malignant distal biliary obstruction. Early diagnosis is difficult to establish as biliary obstruction can be the first presentation of the underlying disease, which can already be at an advanced stage. Consequently, the majority of patients (70%) with malignant distal biliary obstruction are unresectable at the time of diagnosis. The association of clinical findings, laboratory tests, imaging, and endoscopic modalities may help in identifying the underlying cause. Novel endoscopic techniques such as cholangioscopy, intraductal ultrasonography, or confocal laser endomicroscopy have been developed with promising results, but are not used in routine clinical practice. As the number of patients with malignant distal biliary obstruction who will undergo curative surgery is limited, endoscopy has a crucial role in palliation, to relieve biliary obstruction. According to the last European guidelines published in the management of biliary obstruction, self-expandable metal stents have a central place in biliary drainage compared to plastic stents. Endoscopic ultrasound has evolved impressively in the last decades. When standard techniques of biliary cannulation by endoscopic retrograde cholangiopancreatography fail, endoscopic ultrasound-guided biliary drainage is a good option compared to percutaneous drainage.