Interobserver agreement for evaluation of imaging with single operator choledochoscopy: what are we looking at?

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.

Identification of endoscopic predictors of biliary malignancy during digital cholangioscopy

OBJECTIVES

Biliary brushings and biopsies obtained during endoscopic retrograde cholangiopancreatography (ERCP) have a low sensitivity for the diagnosis of malignant biliary strictures. While cholangioscopic analysis is useful, visual criteria have not yet been defined. The aim of this study was to identify visual criteria for the diagnosis of indeterminate biliary strictures (IDBS).

METHODS

A multicenter study was conducted based on the analysis of cholangioscopic recordings of IBDS. Diagnostic criteria were identified in a study group and verified in a validation group.

RESULTS

Four criteria were identified to be associated with malignancy, one negatively ("endobiliary material," odds ratio [OR]  0.62, 95% confidence interval [CI] 0.41-0.92) and three positively ("vascularized villous projections," OR  1.52, 95% CI 1.03-2.24; "twisted or dilated vessels," OR  2.18, 95% CI 1.47-3.24; and "dark color of the mucosa," OR  1.82, 95% CI 1.23-2.70). Between two playbacks, the mean (95% CI) sensitivity of the observer's visual diagnosis increased from 66.1% (60-72) to 73.8% (69-78) (P = 0.004); in the second playback, the kappa value for interobserver agreement ranged between 0.36 (color) and 0.56 (endobiliary material), with a significant improvement (P = 0.0031-0.0001) between the first and second playbacks. Blind assessment by endoscopists not involved in this study had a diagnostic accuracy of 73% (71.4-74.5).

CONCLUSION

The four identified cholangioscopic features are easy to implement in clinical practice and have the potential to increase the level of diagnostic confidence during the workup of IDBS.

Diagnostic accuracy of probe-based confocal laser endomicroscopy and tissue sampling by endoscopic retrograde cholangiopancreatography in indeterminate biliary strictures: a meta‑analysis

Probe-based confocal laser endomicroscopy (pCLE), also known as optical biopsy, is a new endoscopic technique that provides real-time magnification of 1000 × microscopic tissue information to diagnose indeterminate biliary strictures. Tissue sampling by endoscopic retrograde cholangiopancreatography (ERCP) is routinely performed to evaluate indeterminate biliary strictures. To evaluate the accuracy of pCLE and tissue sampling by ERCP in the diagnosis of indeterminate biliary strictures, 18 articles were included from 2008 to 2021 through Embase, PubMed, Web of Science, and Cochrane library databases. The summary estimates for the pCLE diagnosis of indeterminate biliary strictures were: sensitivity 0.88 (95% confidence interval (CI), 0.84-0.91); specificity 0.79 (95% CI 0.74-0.83); and Diagnostic Odds Ratio (DOR) 24.63 (95% CI 15.76-38.48). The summary estimates for tissue sampling by ERCP diagnosis for indeterminate biliary strictures were: sensitivity 0.54 (95% CI 0.49-0.59); specificity 0.96 (95% CI 0.94-0.98); and DOR 11.31 (95% CI 3.90-32.82). The area under the sROC curve of pCLE diagnosis of indeterminate biliary strictures is 0.90 higher than 0.65 of tissue sampling by ERCP. The pCLE is a better approach than tissue sampling by ERCP for the diagnosis of indeterminate biliary strictures by providing real-time microscopic images of the bile ducts.

Advanced Imaging of the Biliary System and Pancreas

Despite advances in noninvasive techniques for imaging the pancreaticobiliary system, several disease processes including indeterminate biliary strictures as well as neuroendocrine tumors, inflammatory pseudotumors, and complex cysts of the pancreas remain difficult to characterize. New endoscopic imaging technologies have emerged to address these challenges. Cholangioscopy and intraductal ultrasound (IDUS) are powerful tools to characterize subtle biliary concretions and strictures. Confocal Laser Endomicroscopy (CLE) and Optical Coherence Tomography (OCT) are emerging approaches for the most difficult biliary lesions. Contrast harmonic endoscopic ultrasound (CH-EUS), elastography, and 3D-EUS are improving the approach to subtle pancreatic lesions, particularly in the context of indeterminate tissue sampling. Pancreatoscopy, pancreatic IDUS, and intracystic CLE hold promise to further improve the assessment of pancreatic cysts. We aim to comprehensively review the emerging clinical evidence for these innovative endoscopic imaging techniques.

Digital Single-operator Cholangioscopy (DSOC) Improves Interobserver Agreement (IOA) and Accuracy for Evaluation of Indeterminate Biliary Strictures: The Monaco Classification

BACKGROUND

Visual characteristics seen during digital single-operator cholangioscopy (DSOC) have not been validated. The aim of this 2-phase study was to define terminology by consensus for the visual diagnosis of biliary lesions to develop a model for optimization of the diagnostic performance of DSOC.

MATERIALS AND METHODS

In phase 1 (criteria identification), video-cholangioscopy clips were reviewed by 12 expert biliary endoscopists, who were blinded to the final diagnosis. Visual criteria were consolidated into the following categories: (1) stricture, (2) lesion, (3) mucosal features, (4) papillary projections, (5) ulceration, (6) abnormal vessels, (7) scarring, (8) pronounced pit pattern.During the second phase (validation), 14 expert endoscopists reviewed DSOC (SpyGlass DS, Boston Scientific) clips using the 8 criteria to assess interobserver agreement (IOA) rate.

RESULTS

In phase 1, consensus for visual findings were categorized into 8 criteria titled the "Monaco Classification." The frequency of criteria were: (1) presence of stricture-75%, (2) presence of lesion type-55%, (3) mucosal features-55%, (4) papillary projections-45%, (5) ulceration-42.5%, (6) abnormal vessels-10%, (7) scarring-40%, and (8) pronounced pit pattern-10%. The accuracy on final diagnosis based on visual impression alone was 70%.In phase 2, the IOA rate using Monaco Classification criteria ranged from slight to fair. The presumptive diagnosis IOA was fair (κ=0.31, SE=0.02), and overall diagnostic accuracy was 70%.

CONCLUSIONS

The Monaco classification identifies 8 visual criteria for biliary lesions on single-operator digital cholangioscopy. Using the criteria, the IOA and diagnostic accuracy rate of DSOC is improved compared with prior studies.

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.

Combination of ERCP-Based Modalities Increases Diagnostic Yield for Biliary Strictures

BACKGROUND

Biliary stricture evaluation with brush cytology and intraductal forceps biopsy carries a low sensitivity, but the combination of newer modalities may improve sensitivity.

AIM

To determine whether the addition of advanced modalities increases diagnostic yield of ERCP-based sampling.

METHODS

This single-center retrospective study evaluates patients with biliary strictures sampled using brush cytology. Operating characteristics were calculated for individual and combinations of modalities including cholangioscopy, fluoroscopy- and cholangioscopy-directed intraductal biopsy, fluorescence in situ hybridization (FISH), and confocal laser endomicroscopy. Analyses under Standard Criteria (SC) included malignant results as "positive" and Expanded Criteria (EC) included "suspicious" and "high-grade dysplasia" results as "positive."

RESULTS

A total of 614 patients were included, and 354 (57.8%) received brush cytology alone, which had a sensitivity of 38.5% (SC) to 40.3% (EC) and a specificity of 97.8% (EC) to 99.3% (SC). Combining brush cytology with fluoroscopy-guided biopsy (n = 259, 42.2%) had a sensitivity of 62.5% (SC) to 67.9% (EC) and specificity of 90.2% (EC) to 96.7% (SC). Adding FISH to brush cytology had a sensitivity of 84.2% (SC) to 87.5% (EC) and specificity of 54.1% (SC and EC), while cholangioscopy visualization addition resulted in a sensitivity of 80.4% (SC) to 92.2% (EC) and specificity of 67.3% (EC) to 89.1% (SC). There were no significant differences in sensitivity and specificity using SC and EC.

CONCLUSIONS

Brush cytology has a low sensitivity, but the addition of other modalities increases sensitivity. There was no difference in specificity between the SC and the EC, supporting the inclusion of "suspicious" impressions with malignant results at our center.

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 Perspective in Cholangiocarcinoma Diagnostic Process

Cholangiocarcinoma is a malignancy arising from the epithelial lining of the intrahepatic or extrahepatic biliary tract. Timely diagnosis is challenging due to its silent clinical course. As reliable laboratory markers are lacking, diagnostic imaging plays a pivotal role. While cross-sectional imaging studies are usually conclusive for intrahepatic lesions, endoscopy plays an essential role in cases of extrahepatic tumors. Rational utilization of different diagnostic methods based on available evidence is needed. This article focuses on the diagnostic role of advanced biliary endoscopy, including endoscopic retrograde cholangiopancreatography, cholangioscopy, endoscopic ultrasonography, and intraductal sonography.

Impact of peroral cholangioscopy on the management of indeterminate biliary conditions: a multicentre prospective trial

BACKGROUND AND AIMS

Single-operator cholangioscopy (SOC) can help diagnose biliopancreatic conditions. The impact of SOC on patient outcome has never been specifically addressed.

PATIENTS AND METHODS

Consecutive patients bearing indeterminate biliary strictures (IDBS), or primary sclerosing cholangitis (PSC) with suspected cholangiocarcinoma, were included. Patients with IDBS had at least one previous inconclusive endoscopic retrograde cholangio pancreatography (ERCP) + cytology. Primary endpoint was the difference in adequacy of management planned before and after SOC with regard to final diagnosis obtained after surgery or 24 months follow-up.

DESIGN

Prospective open-label multicentre trial.

RESULTS

61 patients were included (IDBS: 48; PSC: 13); 70.5% had a benign lesion (IDBS 66.7%, PSC 84.6%). The management adequacy rate was significantly higher after SOC than before SOC overall (p<10^-5), in IDBS (p<0.001) and PSC (p<0.05) patients. SOC induced changes in the management of the majority of patients in all groups (60.3%). The overall sensitivity of combined visual impression and biopsy ranged from 52% to 63.6% depending on investigator or independent expert rating (κ 0.92-0.96), whereas specificity, positive and negative predictive values of SOC were, respectively, 100%, 100% and 83.6%. Patient management observed at the end of follow-up was consistent with that anticipated after SOC in 88.5% overall.

CONCLUSION

Despite a moderate sensitivity for the diagnosis of malignancy, SOC has a dramatic impact on the management of patients with IDBS and PSC with suspected carcinoma. Cholangioscopy might be implemented in the workup of selected patients with challenging diagnosis, when a significant impact on outcome (essentially resection vs conservative management) is to be expected.

Digital cholangioscopy: the diagnostic yield and impact on management of patients with biliary stricture

OBJECTIVES

Biliary strictures frequently present a diagnostic challenge. The aim of this study was to evaluate the impact of digital single-operator cholangioscopy (DSOC) on subsequent treatment of patients with biliary stricture.

METHODS

Consecutive patients undergoing DSOC for biliary stricture were enrolled. Gold standard for final diagnosis included histology from surgical resection. In patients without surgery, clinical evaluation methods and repeated imaging studies were used for comparison of DSOC findings and final diagnosis. Patients were followed-up prospectively focusing on subsequent treatment.

RESULTS

Among 30 enrolled patients, final diagnosis was malignant in 13 (43%) and benign in 17 (57%). The sensitivity and specificity of visual impression in diagnosing malignant stricture were 100% (95% CI: 75 - 100) and 76% (95% CI: 50 - 93), respectively. The sensitivity and specificity for biopsy were 92% (95% CI: 62 - 100) and 100% (95% CI: 78 - 100), respectively. One (3%) case of complicating cholangitis with fatal outcome occurred. Final treatment included surgery in 7 (23%), endoscopy in 18 (60%) and chemotherapy in 3 (10%) of patients.

CONCLUSIONS

In this study, favorable operating characteristics of DSOC were confirmed. Absolute negative predictive value of visual impression provided reassurance to patients with benign strictures who avoided unnecessary surgery in 53%. One (3%) case of cholangitis with fatal outcome occurred.

Endoscopic retrograde cholangiopancreatography, lights and shadows: Handle with care

The role of endoscopic retrograde cholangiopancreatography (ERCP) has dramatically changed in the last years, mainly into that of a therapeutic procedure. The treatment of benign biliary disease, like “difficult” choledocolithiasis, with endoscopic papillary large balloon dilation combined with endoscopic sphinterotomy has proven an effective and safe technique. Moreover, safety in ERCP has improved as well, with the prevention of post-ERCP pancreatitis and patient-to-patient transmission of infections. The advent of self-expandable metal stenting has radically changed the management of biliopancreatic malignant strictures, while the role for therapy of benign strictures is still controversial. In addition, cholangioscopy (though the direct visualization of the biliopancreatic ductal system) has allowed for characterization of indeterminate biliary strictures and facilitated rescue therapy of large biliary stones deemed removable. Encouraging data from tissue ablation techniques, such as photodynamic therapy and radiofrequency ablation, need to be confirmed by large sample size clinical controlled trials. On the other hand, we have no drug-coated stents yet available to implant and evidence for the use of biodegradable stents is still weak. The competency and privileging of ERCP and endoscopic ultrasonography have been analyzed longer but the switch between the two procedures, at the same time, is becoming ordinary; as such, the endoscopist interested in this field should undergo parallel edification through training plans. Finally, the American Society for Gastrointestinal Endoscopy’s statement on non-anesthesiologist administration of propofol for gastrointestinal endoscopy is not actually endorsed by the European Society of Anaesthesiology, having many medical-legal implications in some European countries.

The interobserver agreement of optical features used to differentiate benign from neoplastic biliary lesions assessed at balloon-assisted cholangioscopy

BACKGROUND AND AIM

Balloon-assisted cholangioscopy allows mucosal assessment of the biliary tree with pediatric endoscopes. No validated optical criteria exist to differentiate benign from neoplastic biliary lesions. We aimed to identify, validate, and revalidate optical features differentiating benign from neoplastic biliary lesions. Furthermore, we aimed to determine whether cholangioscopic appearance allows endoscopists to accurately differentiate benign from neoplastic biliary lesions.

METHODS

Baseline: from 44 de-identified balloon-assisted cholangioscopy videos, a blinded investigator analyzed potential optical features distinguishing benign from neoplastic biliary lesions.

VALIDATION

during the initial "teaching phase," 20 endoscopists viewed video clips of 11 optical features identified in the baseline study. At the subsequent "test phase," 20 further video clips were assessed by the endoscopists blinded to clinical details and questionnaires completed for the presence or absence of optical features, favored diagnosis and diagnostic confidence. Revalidation: The six identified optical features from the validation study with at least moderate agreement were revalidated the same way 12 months later assessing 20 new lesions.

RESULTS

Baseline: 11 optical features were found to differentiate benign from neoplastic biliary lesions. Validation and revalidation: six optical features demonstrated at least moderate interobserver agreement (irregular margin, dark mucosa, adherent mucous, papillary projections, tubular, or branched/disorganized surface structures). Endoscopists correctly diagnosed lesions as benign in 89% and neoplastic in 83%. When highly confident, endoscopists correctly diagnosed 96% of benign and 87% neoplastic lesions.

CONCLUSIONS

Six features were validated and revalidated to differentiate benign from neoplastic biliary lesions. When highly confident with a diagnosis, endoscopists usually differentiate benign from neoplastic biliary lesions.

Indeterminate biliary strictures: a simplified approach

Pre-operative evaluation of biliary strictures remains challenging. The dilemma that exists is how to balance the risk of failing to detect malignancy and the potential morbidity caused by unnecessary surgery in patients with benign etiologies. With emerging novel diagnostic modalities, this study aims to assess the efficacy of diagnostic techniques and facilitate a clinical approach to indeterminate biliary strictures. Areas covered: Conventional imaging modalities are crucial in identifying the location of a stricture and are helpful for choosing further diagnostic modalities. Utilization of endoscopic techniques, including endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic ultrasound (EUS), is key in establishing a diagnosis. The emergence of novel diagnostic modalities, such as fluorescence in-situ hybridization (FISH), peroral cholangioscopy (POC), intraductal endoscopic ultrasound (IDUS) and confocal laser endomicroscopy (CLE), enhance the diagnostic yield in the evaluation of indeterminate biliary strictures. Expert commentary: More reliable and validated visual criteria for differentiating malignancy from benign biliary conditions, utilizing advanced imaging modalities such as POC and CLE, need to be established. It is of significance to further evaluate these novel diagnostic modalities through ongoing trials and to develop a diagnostic algorithm that reconciles cost-effectiveness with diagnostic accuracy.

Recent developments in choledochoscopy: technical and clinical advances

Peroral cholangioscopy has become an important tool in the diagnosis and treatment of a variety of biliary diseases, ranging from indeterminate biliary strictures to bile duct stones. Although the first cholangioscopy was performed in the 1970s, recent technological advances have provided us with cholangioscopes that yield high-resolution images, possess single-operator capability, and have ultrathin design to allow easier maneuverability and detailed imaging of the biliary tract. We review here the currently available devices for peroral cholangioscopy, their clinical applications, limitations, and complications.

Diagnosing Biliary Malignancy

The most common malignant causes of biliary strictures are pancreatic cancer and cholangiocarcinoma. Differentiating between malignant and benign causes of biliary strictures has remained a clinical challenge. Endoscopic retrograde cholangiopancreatography (ERCP) remains the mainstay and first-line method of tissue diagnosis but has a poor diagnostic yield. This article reviews the causes of biliary strictures, the initial clinical evaluation of biliary obstruction, the diagnostic yield of ERCP-based sampling methods, the role of newer tools in the armamentarium for evaluating strictures, and ways to address the ongoing challenge of stricture evaluation in patients with primary sclerosing cholangitis.

Cholangiocarcinoma and malignant bile duct obstruction: A review of last decades advances in therapeutic endoscopy

In the last decades many advances have been achieved in endoscopy, in the diagnosis and therapy of cholangiocarcinoma, however blood test, magnetic resonance imaging, computed tomography scan may fail to detect neoplastic disease at early stage, thus the diagnosis of cholangiocarcinoma is achieved usually at unresectable stage. In the last decades the role of endoscopy has moved from a diagnostic role to an invaluable therapeutic tool for patients affected by malignant bile duct obstruction. One of the major issues for cholangiocarcinoma is bile ducts occlusion, leading to jaundice, cholangitis and hepatic failure. Currently, endoscopy has a key role in the work up of cholangiocarcinoma, both in patients amenable to surgical intervention as well as in those unfit for surgery or not amenable to immediate surgical curative resection owing to locally advanced or advanced disease, with palliative intention. Endoscopy allows successful biliary drainage and stenting in more than 90% of patients with malignant bile duct obstruction, and allows rapid reduction of jaundice decreasing the risk of biliary sepsis. When biliary drainage and stenting cannot be achieved with endoscopy alone, endoscopic ultrasound-guided biliary drainage represents an effective alternative method affording successful biliary drainage in more than 80% of cases. The purpose of this review is to focus on the currently available endoscopic management options in patients with cholangiocarcinoma.

Per oral cholangiopancreatoscopy in pancreatico biliary diseases--expert consensus statements

AIM

To provide consensus statements on the use of per-oral cholangiopancreatoscopy (POCPS).

METHODS

A workgroup of experts in endoscopic retrograde cholangiopancreatography (ERCP), endosonography, and POCPS generated consensus statements summarizing the utility of POCPS in pancreaticobiliary disease. Recommendation grades used validated evidence ratings of publications from an extensive literature review.

RESULTS

Six consensus statements were generated: (1) POCPS is now an important additional tool during ERCP; (2) in patients with indeterminate biliary strictures, POCS and POCS-guided targeted biopsy are useful for establishing a definitive diagnosis; (3) POCS and POCS-guided lithotripsy are recommended for treatment of difficult common bile duct stones when standard techniques fail; (4) in patients with main duct intraductal papillary mucinous neoplasms (IPMN) POPS may be used to assess extent of tumor to assist surgical resection; (5) in difficult pancreatic ductal stones, POPS-guided lithotripsy may be useful in fragmentation and extraction of stones; and (6) additional indications for POCPS include selective guidewire placement, unexplained hemobilia, assessing intraductal biliary ablation therapy, and extracting migrated stents.

CONCLUSION

POCPS is important in association with ERCP, particularly for diagnosis of indeterminate biliary strictures and for intra-ductal lithotripsy when other techniques failed, and may be useful for pre-operative assessment of extent of main duct IPMN, for extraction of difficult pancreatic stones, and for unusual indications involving selective guidewire placement, assessing unexplained hemobilia or intraductal biliary ablation therapy, and extracting migrated stents.

Probe-based confocal laser endomicroscopy for indeterminate biliary strictures: refinement of the image interpretation classification

Background. Accurate diagnosis and clinical management of indeterminate biliary strictures are often a challenge. Tissue confirmation modalities during Endoscopic Retrograde Cholangiopancreatography (ERCP) suffer from low sensitivity and poor diagnostic accuracy. Probe-based confocal laser endomicroscopy (pCLE) has been shown to be sensitive for malignant strictures characterization (98%) but lacks specificity (67%) due to inflammatory conditions inducing false positives. Methods. Six pCLE experts validated the Paris Classification, designed for diagnosing inflammatory biliary strictures, using a set of 40 pCLE sequences obtained during the prospective registry (19 inflammatory, 6 benign, and 15 malignant). The 4 criteria used included (1) multiple thin white bands, (2) dark granular pattern with scales, (3) increased space between scales, and (4) thickened reticular structures. Interobserver agreement was further calculated on a separate set of 18 pCLE sequences. Results. Overall accuracy was 82.5% (n = 40 retrospectively diagnosed) versus 81% (n = 89 prospectively collected) for the registry, resulting in a sensitivity of 81.2% (versus 98% for the prospective study) and a specificity of 83.3% (versus 67% for the prospective study). The corresponding interobserver agreement for 18 pCLE clips was fair (k = 0.37). Conclusion. Specificity of pCLE using the Paris Classification for the characterization of indeterminate bile duct stricture was increased, without impacting the overall accuracy.

Interobserver agreement for single operator choledochoscopy imaging: can we do better?

Background. The SpyGlass Direct Visualization System (Boston Scientific, Natick, MA) is routinely used during single operator choledochoscopy (SOC) to identify biliary lesions or strictures with a diagnostic accuracy up to 88%. The objective of this study was to determine the interobserver agreement (IOA) of modified scoring criteria for diagnosing biliary lesions/strictures. Methods. 27 SPY SOC video clips were reviewed and scored by 9 interventional endoscopists based on published criteria that included the presence and severity of surface structure, vasculature visualization, lesions, and findings. Results. Overall IOA was "slight" for all variables. The K statistics are as follows: surface (K = 0.12, SE = 0.02); vessels (K = 0.14, SE = 0.02); lesions (K = 0.11, SE = 0.02); findings (K = 0.08, SE = 0.03); and final diagnosis (K = 0.08, SE = 0.02). The IOA for "findings" and "final diagnosis" was also only "slight." The final diagnosis was malignant (11), benign (11), and indeterminate (5). Conclusion. IOA using the modified criteria of SOC images was slight to almost poor. The average accuracy was less than 50%. These findings reaffirm that imaging criteria for benign and malignant biliary pathology need to be formally established and validated.

Diagnostic utility of single-user peroral cholangioscopy in sclerosing cholangitis

OBJECTIVE

To evaluate the diagnostic utility of single-operator peroral cholangioscopy (SOC) in patients with sclerosing cholangitis.

METHODS

All patients with sclerosing cholangitis who underwent SOC procedures due to suspicious biliary strictures, in one Swedish and four UK tertiary centers in 2008-2012, were retrospectively enrolled. For each SOC procedure in sclerosing cholangitis, another one attempted due to a single biliary stricture in the same center and calendar year was randomly selected as control. Patients were followed up until death or last clinic visit until November 2012.

RESULTS

Fifty-four SOC procedures were attempted in 52 sclerosing cholangitis patients (48 with primary sclerosing cholangitis, 4 with IgG4-related sclerosing cholangitis). Cannulation with the SOC system failed more frequently in sclerosing cholangitis (15% vs. 2% in controls; p = 0.015). The sensitivity, specificity, and accuracy of SOC (including tissue sampling) for cancer diagnosis were similar in sclerosing cholangitis and controls (50% vs. 55%, 100% vs. 97%, and 88% vs. 80%, respectively) with largely overlapping confidence intervals. Adverse events were more common in sclerosing cholangitis, due to an increased frequency of cholangitis (11% vs. 2% in controls; p = 0.051).

CONCLUSIONS

SOC is equally accurate in cancer diagnosis in sclerosing cholangitis and patients with single biliary strictures. However, cholangioscope insertion may be hampered by bile duct narrowing and post-SOC cholangitis is more common in sclerosing cholangitis.