Characterization of biliary strictures using intraductal ultrasonography: comparison with percutaneous cholangioscopic biopsy

Diagnosis of Cholangiocarcinoma

Cholangiocarcinoma (CCA), a tumor of the bile duct epithelium, is increasing in incidence. CCA remains a highly fatal malignancy because early diagnosis is difficult. Based on its anatomical location, CCA can be categorized into the following three groups: perihilar, intrahepatic, and extrahepatic. Patients with CCA complain of asymptomatic jaundice, weight loss, and right upper quadrant abdominal discomfort. Imaging modalities, including transabdominal ultrasound, computed tomography, and magnetic resonance imaging, play an important role in detecting tumors as well as guiding biopsy procedures and staging workups in CCA. Characteristically, extrahepatic CCA shows abrupt changes in ductal diameter with upstream ductal dilation. Endoscopic ultrasound (EUS) and endoscopic retrograde cholangiopancreatography (ERCP) are recommended as the next step in the evaluation of extrahepatic CCA. Tissue is obtained through EUS-FNA or ERCP (biopsy, brush cytology), and therapeutic intervention (such as stent insertion) is performed with ERCP. Moreover, several serum tumor markers (carbohydrate antigen 19-9 and carcinoembryonic antigen) can be useful in diagnosing CCA in some patients.

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.

Controversies in EUS: Do we need miniprobes?

This is the fifth in a series of papers entitled "Controversies in EUS." In the current paper, we deal with high-resolution catheter probes, otherwise known as EUS miniprobes (EUS-MPs). The application of miniprobes for early carcinomas in the entire intestinal tract, for subepithelial lesions, and for findings in the bile duct and pancreatic duct as well as endobronchial use is critically discussed. Submucous lesions, especially in the colon, but also early carcinomas in special cases are considered the most important indications. The argument is illustrated by numerous examples.

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.

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.

Advances in Endoscopic Imaging of the Biliary Tree

Direct endoscopic imaging of the biliary tree is increasingly performed by endoscopists since the introduction of digital single-operator cholangioscopy. In parallel, there have been several advances to overcome the challenges associated with direct peroral cholangioscopy with development of multibending cholangioscopes and new devices to enable direct placement of an endoscope into the biliary tree without a supporting duodenoscope. The indications for cholangioscopy are also evolving with newer indications, such as intraductal lithotripsy, foreign body (mostly stent) removal, guide wire cannulation of specific ducts, photodynamic therapy for cholangiocarcinoma, and performance of fluoroscopy-free cholangiography. There has also been progress in image enhancement during cholangioscopy and additional imaging techniques, such as intraductal ultrasound, confocal laser endomicroscopy, and optical coherence tomography.

Prospective Comparison of Intraductal Ultrasonography-Guided Transpapillary Biopsy and Conventional Biopsy on Fluoroscopy in Suspected Malignant Biliary Strictures

Background/Aims

In suspected malignant biliary strictures (MBSs), the diagnostic yield of endoscopic retrograde cholangiopancreatography (ERCP)-based tissue sampling is limited. Transpapillary forceps biopsy (TPB) under intraductal ultrasonography (IDUS) guidance is expected to improve the diagnostic accuracy in patients with indeterminate biliary strictures. We evaluated the usefulness of IDUS-guided TPB in patients with suspected MBS.

Methods

Consecutive patients with suspected MBS were prospectively enrolled in the study. ERCP with IDUS was performed in all patients. Both conventional TPB and IDUS-guided TPB on fluoroscopy were performed in each patient. The primary outcome was the diagnostic accuracy of conventional TPB and IDUS-guided TPB.

Results

The technical success rate of IDUS-guided TPB was 97.0% (65/67 patients). Of these 65 patients, the final diagnosis was malignancy in 61 patients (93.8%). On IDUS, the most common finding of IDUS was an intraductal infiltrating lesion in 29 patients (47.5%). The overall diagnostic accuracy was significantly higher using IDUS-guided TPB than that using conventional TPB (90.8% vs 76.9%, p=0.027). According to the subgroup analysis based on the tumor morphology, IDUS-guided TPB had a significantly higher cancer detection rate than conventional TPB for intraductal infiltrating lesions (89.6% vs 65.5%, p=0.028).

Conclusions

IDUS-guided TPB appears to improve the accuracy of histological diagnosis in patients with MBS.

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.

Proposal of a diagnostic algorithm for intraductal ultrasonography to distinguish between benign and malignant biliary strictures

To reexamine the recognizability of intraductal ultrasonography (IDUS) findings from an imaging database and propose a novel algorithm for clinical application. IDUS images of 102 patients who had undergone IDUS examinations for indeterminate causes of common bile duct dilation were independently reviewed by two endoscopists. The strength of the inter-rater agreement between the endoscopists was analyzed using Cohen's kappa (κ). An algorithm was implemented by arranging the IDUS characteristics according to their recognizability. The proposed algorithm was evaluated by examining the inter-rater agreement and diagnostic accuracy before and after the use of the algorithm. The strength of the inter-rater agreement was good for common bile duct stones with or without acoustic shadowing; intraluminal tumors; or bile duct wall thicknesses of more than or equal to 9 mm (κ > 0.8); followed by intraluminal hypoechoic nodules without common bile duct stone characteristics (κ = 0.771); and finally eccentric wall thickening, outer layer disruption, irregular mucosa, and destructed mural layers (κ: 0.595-0.419). Our algorithm improved the strength of inter-rater agreement with a diagnostic accuracy of 81.4%. We proposed an algorithm according to the recognizability of IDUS characteristics, and it can be used by endoscopists to evaluate such characteristics and determine the cause of biliary obstruction.

Comparison of intraductal ultrasonography-directed and cholangiography-directed endoscopic retrograde biliary drainage in patients with a biliary obstruction

BACKGROUND/AIMS

Endoscopic retrograde biliary drainage (ERBD) has become a standard procedure in patients with a biliary obstruction. Intraductal ultrasonography (IDUS) has emerged as a new tool for managing extrahepatic biliary diseases. IDUS-directed ERBD can be performed without conventional cholangiography (CC). The goal of this study was to assess the effectiveness and safety of IDUS-directed ERBD compared to CC-directed ERBD in patients with an extrahepatic biliary obstruction.

METHODS

A total of 210 patients who had undergone IDUS-directed ERBD (IDUS-ERBD, n = 105) and CC-directed ERBD (CC-ERBD, n = 105) between October 2013 and April 2014 were analyzed retrospectively. The primary outcome measure was the procedural success rate. Secondary outcome measures included clinical outcomes, total procedure time, radiation exposure time, and overall complication rates.

RESULTS

The total technical success rate of ERBD was 100% (105/105) in the IDUS-ERBD and CC-ERBD groups. Mean procedure time was slightly prolonged in the IDUS-ERBD group than that in the CC-ERBD group (32.1 ± 9.9 minutes vs. 28.4 ± 11.6 minutes, p = 0.023). Mean radiation exposure time was one-third less in the IDUS-ERBD group than that in the CC-ERBD group (28.0 ± 49.3 seconds vs. 94.2 ± 57.3 seconds, p < 0.001). No significant differences in complication rates were detected between the groups.

CONCLUSIONS

IDUS-ERBD was equally effective and safe as CC-ERBD in patients with an extrahepatic biliary obstruction. Although IDUS-ERBD increased total procedure time, it significantly decreased radiation exposure.

Evaluation of Intraductal Ultrasonography, Endoscopic Brush Cytology and K-ras, P53 Gene Mutation in the Early Diagnosis of Malignant Bile Duct Stricture

Background:

In qualitative diagnosis of bile duct stenosis, single diagnostic measure is difficult to make a correct diagnosis, to combine several diagnostic techniques may be helpful to make an accurate diagnosis. The aim of this study was to evaluate the value of intraductal ultrasonography (IDUS), endoscopic brush cytology and K-ras, P53 gene mutation in the early diagnosis of malignant biliary stricture.

Methods:

From February 2012 to February 2013, 84 patients with suspected malignant biliary stricture were performed IDUS firstly, then endoscopic brush cytology and finally K-ras, P53 gene mutation detection, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of all above ways were evaluated and compared.

Results:

Of 84 patients, 52 cases were ultimately diagnosed malignant biliary stenosis; of which, 9 cases had no recurrence or metastasis to other organs after radical operation during the follow-up period. IDUS combined with brush cytology and K-ras + P53 gene mutation detection had obvious advantage in the sensitivity, accuracy and negative predictive value than any other joint detection and single detection (the advantage was more significant compared with IDUS + brush cytology or any single detection P < 0.01). There were obvious statistical significance in the sensitivity and accuracy between IDUS + brush cytology + P53 or IDUS + brush cytology + K-ras and IDUS + brush cytology or IDUS (P < 0.05). There was no statistical significance in the sensitivity, specificity, positive predictive value, negative predictive value and accuracy between IDUS + brush cytology + P53 and IDUS + brush cytology + K-ras (P > 0.05).

Conclusions:

IDUS combined with brush cytology and K-ras, P53 gene mutation detection is better than the separate detection and contribute to the early diagnosis of malignant biliary stricture. Its more widespread use is recommended.

Diagnostic Utility of Endoscopic Retrograde Cholangiography/Intraductal Ultrasound (ERC/IDUS) in Distinguishing Malignant from Benign Bile Duct Obstruction

BACKGROUND AND AIM

Accurately differentiating malignant diseases from benign ones in patients having bile duct obstruction is of significant importance and remains a major clinical problem. This study investigated the diagnostic yield of endoscopic retrograde cholangiography/intraductal ultrasound (ERC/IDUS) in distinguishing malignant from benign bile duct obstruction and assessed some image findings from ERC/IDUS which might be useful in differentiation.

METHODS

From January 2008 to January 2015, patients who underwent ERC/IDUS for bile duct obstruction were enrolled. Patient's ERC/IDUS diagnosis was compared with the final diagnosis determined by pathologic findings and/or clinical outcome of follow-up.

RESULTS

One hundred and ninety-three patients with bile duct obstruction were included. IDUS correctly identified 94 of 97 malignant diseases and 76 of 96 benign diseases with sensitivity, specificity, and accuracy rate of 96.91, 79.17, and 88.08 %, respectively. Additionally, the accuracy rate of IDUS for diagnosis of proximal bile duct obstruction was higher than that of distal bile duct obstruction (98.08 vs. 82.73 %, p = 0.006). Besides, there was a significant difference in the length at the obstruction site between benign and malignant diseases (13.76 ± 7.37 vs. 19.97 ± 11.37 mm, p < 0.001) as well as thickness of bile duct wall at the site of obstruction (3.06 ± 0.92 vs. 7.03 ± 3.70 mm, p = 0.008). Biliary wall thickness >7 mm without extrinsic compression had a positive predictive value (PPV) of 100 % for including malignancy, while length ≧20 mm demonstrated a PPV of 93.44 %.

CONCLUSIONS

ERC/IDUS is effective in distinguishing malignant from benign bile duct obstruction, thus helping in further clinical management.

Evaluation and management of intrahepatic and extrahepatic cholangiocarcinoma

Cholangiocarcinomas are rare biliary tract tumors that are often challenging to diagnose and treat. Cholangiocarcinomas are generally categorized as intrahepatic or extrahepatic depending on their anatomic location. The majority of patients with cholangiocarcinoma do not have any of the known or suspected risk factors and present with advanced disease. The optimal evaluation and management of patients with cholangiocarcinoma requires thoughtful integration of clinical information, imaging studies, cytology and/or histology, as well as prompt multidisciplinary evaluation. The current review focuses on recent advances in the diagnosis and treatment of patients with cholangiocarcinoma and, in particular, on the role of endoscopy, surgery, transplantation, radiotherapy, systemic therapy, and liver-directed therapies in the curative or palliative treatment of these individuals. Cancer 2016;122:1349-1369. © 2016 American Cancer Society.

Advanced endoscopic imaging of indeterminate biliary strictures

Endoscopic evaluation of indeterminate biliary strictures (IDBSs) has evolved considerably since the development of flexible fiberoptic endoscopes over 50 years ago. Endoscopic retrograde cholangiography pancreatography (ERCP) was introduced nearly a decade later and has since become the mainstay of therapy for relieving obstruction of the biliary tract. However, longstanding methods of ERCP-guided tissue acquisition (i.e., biliary brushings for cytology and intraductal forceps biopsy for histology) have demonstrated disappointing performance characteristics in distinguishing malignant from benign etiologies of IDBSs. The limitations of these methods have thus helped drive the search for novel techniques to enhance the evaluation of IDBSs and thereby improve diagnosis and clinical care. These modalities include, but are not limited to, endoscopic ultrasound, intraductal ultrasound, cholangioscopy, confocal endomicroscopy, and optical coherence tomography. In this review, we discuss established and emerging options in the evaluation of IDBSs.

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.

Biliary strictures: diagnostic considerations and approach

Biliary strictures present a diagnostic challenge, especially when no etiology can be ascertained after laboratory evaluation, abdominal imaging and endoscopic retrograde cholangiopancreatography (ERCP) sampling. These strictures were traditionally classified as indeterminate strictures, although with advances in endoscopic techniques and better understanding of hepato-biliary pathology, more are being correctly diagnosed. The implications of missing a malignancy in patients with biliary strictures—and hence delaying surgery—are grave but a significant number of patients (up to 20%) undergoing surgery for suspected biliary malignancy can have benign pathology. The diagnostic approach to these patients involves detailed history and physical examination and depends on the presence or absence of jaundice, level of obstruction, and presence or absence of a mass lesion. While abdominal imaging helps to find the level of obstruction and provides a ‘road map' for further endoscopic investigations, tissue diagnosis is usually needed to make decisions on management. Initially ERCP was the only modality to investigate these strictures but now, with the development of endoscopic ultrasound with fine needle aspiration and the availability of newer techniques such as intraductal ultrasound, single-operator cholangioscopy and confocal laser endomicroscopy, the diagnostic approach to biliary strictures has changed significantly. In this review, we will focus on the decision-making process for patients with biliary strictures and discuss the key decision points that should dictate further diagnostic investigations at each step.

Role of endoscopic ultrasonography in the evaluation of extrahepatic cholangiocarcinoma

Cholangiocarcinoma is a malignancy that arises from biliary epithelium and is associated with a poor prognosis. Accurate preopera-tive diagnosis and staging of cholangiocarcinoma continues to remain difficult. Endoscopic retrograde cholangiopancreatography (ERCP) is the most commonly performed procedure for cholangiocarcinoma and can provide a tissue diagnosis through brush cytology of the bile duct. However, the sensitivity of biliary brush cytology to diagnose cholangiocarcinoma may be as low as 30%. Endoscopic ultrasound (EUS) is a diagnostic modality which may overcome the limitations of other imaging and biopsy techniques in this setting. EUS can complement the role of ERCP and provide a tissue diagnosis through fine needle aspiration (FNA) and staging through ultrasound imaging. There is currently a paucity of data about the exact role of EUS for the diagnosis of cholan-giocarcinoma in patients with indeterminate extrahepatic biliary strictures. Although multiple studies have shown that EUS is more accurate than ERCP and radiologic imaging for identifying a biliary mass and diagnosing cholangiocarcinoma, the sensitivities are variable. More importantly, the incidence of false negative results is not negligible, though the specificity is close to 100%. There is also controversy regarding the role of EUS-FNA, since even though this may increase diagnosis, it can also lead to tumor seeding.

Role of endoscopic ultrasonography in the evaluation of extrahepatic cholangiocarcinoma

Cholangiocarcinoma is a malignancy that arises from biliary epithelium and is associated with a poor prognosis. Accurate preopera-tive diagnosis and staging of cholangiocarcinoma continues to remain difficult. Endoscopic retrograde cholangiopancreatography (ERCP) is the most commonly performed procedure for cholangiocarcinoma and can provide a tissue diagnosis through brush cytology of the bile duct. However, the sensitivity of biliary brush cytology to diagnose cholangiocarcinoma may be as low as 30%. Endoscopic ultrasound (EUS) is a diagnostic modality which may overcome the limitations of other imaging and biopsy techniques in this setting. EUS can complement the role of ERCP and provide a tissue diagnosis through fine needle aspiration (FNA) and staging through ultrasound imaging. There is currently a paucity of data about the exact role of EUS for the diagnosis of cholan-giocarcinoma in patients with indeterminate extrahepatic biliary strictures. Although multiple studies have shown that EUS is more accurate than ERCP and radiologic imaging for identifying a biliary mass and diagnosing cholangiocarcinoma, the sensitivities are variable. More importantly, the incidence of false negative results is not negligible, though the specificity is close to 100%. There is also controversy regarding the role of EUS-FNA, since even though this may increase diagnosis, it can also lead to tumor seeding.

Endoscopic ultrasonography for inflammatory distal biliary stricture: Analysis of 165 cases

AIM: To explore the value of endoscopic ultrasonography (EUS) in the treatment of inflammatory distal biliary stricture.

METHODS: The clinical data for 165 patients with inflammatory distal biliary stricture who underwent EUS from March 2010 to March 2013 were retrospectively analyzed.

RESULTS: A total of 256 EUS treatments were performed in 165 patients. Endoscopic retrograde cholangiopancreatography (ERCP) and EUS were selected based on the clinical condition. Endoscopic nasobiliary drainage and/or endoscopic retrograde biliary drainage were separately used. Clinical symptoms were relieved and hepatic function was improved in all patients. Bile duct pressure was reduced. The success rate of ERCP was 98.8%. The rate of complications was 4.84% (8/165). Three patients developed post-ERCP hyperamylasemia, 3 patients developed mild cholangeitis, and 2 patients developed acute pancreatitis. During a follow-up period of 1-37 mo (average, 17.8 mo ± 5.3 mo), no stricture recurrence was found. Stents were removed in 121 cases, but stent replacement was required in another 29 cases.

CONCLUSION: Endoscopic ultrasonography is a safe, effective and mini-invasive method for inflammatory distal biliary stricture.

Advanced techniques for endoscopic biliary imaging: cholangioscopy, endoscopic ultrasonography, confocal, and beyond

Cholangioscopy, endosonography, and confocal microscopy represent important technologies that expand biliary imaging beyond a level previously realized by noninvasive modalities (ultrasonography, computed tomography, and magnetic resonance cholangiopancreatography) and endoscopic retrograde cholangiopancreatography. Endoscopic ultrasonography has shown efficacy for the evaluation of indeterminate biliary strictures; however, this modality seems most reliable for distal bile duct abnormalities and in the setting of a moderate to high pretest probability for malignancy. Further refinement of these technologies, validation of their respective diagnostic criteria, and study within the context of comparative, randomized trials are needed and will contribute greatly to expedient patient care.

Endoscopic evaluation of bile duct strictures

Differentiating between malignant and benign bile duct strictures is often challenging. Endoscopic retrograde cholangiopancreatography with brush cytology and/or endobiliary forceps biopsy is routinely performed. Advanced cytologic methods such as fluorescence in situ hybridization or digital image analysis increases the sensitivity of cytology. Endoscopic ultrasonography enables detailed examination of tissues surrounding the bile duct stricture and offers the advantage of fine-needle aspiration. Intraductal ultrasonography enables detailed evaluation of bile duct wall layers, and cholangioscopy offers direct visualization of the bile duct lesions. Novel techniques of probe-based confocal laser endomicroscopy and optical coherence tomography have introduced the era of in vivo histology.

Current endoscopic approach to indeterminate biliary strictures

Biliary strictures are considered indeterminate when basic work-up, including transabdominal imaging and endoscopic retrograde cholangiopancreatography with routine cytologic brushing, are non-diagnostic. Indeterminate biliary strictures can easily be mischaracterized which may dramatically affect patient’s outcome. Early and accurate diagnosis of malignancy impacts not only a patient’s candidacy for surgery, but also potential timely targeted chemotherapies. A significant portion of patients with indeterminate biliary strictures have benign disease and accurate diagnosis is, thus, paramount to avoid unnecessary surgery. Current sampling strategies have suboptimal accuracy for the diagnosis of malignancy. Emerging data on other diagnostic modalities, such as ancillary cytology techniques, single operator cholangioscopy, and endoscopic ultrasonography-guided fine needle aspiration, revealed promising results with much improved sensitivity.

Usefulness of Intraductal Ultrasonography in the Diagnosis of Cholangiocarcinoma and IgG4-Related Sclerosing Cholangitis

The technique of intraductal ultrasonography (IDUS) of the bile duct with a thin-caliber probe and a ropeway system has provided excellent images of the bile duct and periductal structures and is an easy transpapillary approach. In addition, once the guide wire is inserted into the bile duct, IDUS and transpapillary biopsy after endoscopic retrograde cholangiopancreatography can be performed in a single session. Here, we review the usefulness of IDUS in the diagnosis of cholangiocarcinoma and IgG4-related sclerosing cholangitis.

Endoscopic retrograde cholangioscopy and advanced biliary imaging

Developments in endoscopic retrograde cholangioscopy provide multiple new advanced methods of biliary imaging. Cholangioscopy provides direct visualization of epithelium with white light as well as advanced modalities, such as narrow band imaging and autofluorescence. In vivo histologic images can be achieved with confocal endomicroscopy. Cross-sectional imaging is also possible with intraductal ultrasonography and optical coherence tomography. This article describes these advanced imaging techniques, which can be used together to assist in the diagnosis of biliary strictures and lesions.

Endoscopic treatment for biliary stricture secondary to chronic pancreatitis

The causes of benign biliary stricture include chronic pancreatitis, primary/immunoglobulin G4-related sclerosing cholangitis and complications of surgical procedures. Biliary stricture due to fibrosis as a result of inflammation is sometimes encountered in patients with chronic pancreatitis. Frey's procedure, which can provide pancreatic duct drainage with decompression of biliary stricture, can be an initial treatment for chronic pancreatitis with pancreatic and bile duct strictures with upstream dilation. When patients are high-risk surgical candidates or hesitate to undergo surgery, endoscopic treatment appears to be a potential second-line therapy. Placement of multiple plastic stents is currently considered to be the best choice as endoscopic treatment for biliary stricture due to chronic pancreatitis. Temporary placement with a fully covered metal stent has become an attractive option due to the lesser number of endoscopic retrograde cholangiopancreatography (ERCP) sessions and its large diameter. Further clinical trials comparing multiple placement of plastic stents with placement of a covered metal stent for biliary stricture secondary to chronic pancreatitis are awaited.

Real-time PCR-based analysis of the human bile microRNAome identifies miR-9 as a potential diagnostic biomarker for biliary tract cancer

Biliary tract cancer (BTC) is often difficult to diagnose definitively, even through histological examination. MicroRNAs (miRNAs) regulate a variety of physiological processes. In recent years, it has been suggested that profiles for circulating miRNAs, as well as those for tissue miRNAs, have the potential to be used as diagnostic biomarkers for cancer. The aim of this study was to confirm the existence of miRNAs in human bile and to assess their potential as clinical biomarkers for BTC. We sampled bile from patients who underwent biliary drainage for biliary diseases such as BTC and choledocholithiasis. PCR-based miRNA detection and miRNA cloning were performed to identify bile miRNAs. Using high-throughput real-time PCR-based miRNA microarrays, the expression profiles of 667 miRNAs were compared in patients with malignant disease (n = 9) and age-matched patients with the benign disease choledocholithiasis (n = 9). We subsequently characterized bile miRNAs in terms of stability and localization. Through cloning and using PCR methods, we confirmed that miRNAs exist in bile. Differential analysis of bile miRNAs demonstrated that 10 of the 667 miRNAs were significantly more highly expressed in the malignant group than in the benign group at P<0.0005. Setting the specificity threshold to 100% showed that some miRNAs (miR-9, miR-302c*, miR-199a-3p and miR-222*) had a sensitivity level of 88.9%, and receiver-operating characteristic analysis demonstrated that miR-9 and miR-145* could be useful diagnostic markers for BTC. Moreover, we verified the long-term stability of miRNAs in bile, a characteristic that makes them suitable for diagnostic use in clinical settings. We also confirmed that bile miRNAs are localized to the malignant/benign biliary epithelia. These findings suggest that bile miRNAs could be informative biomarkers for hepatobiliary disease and that some miRNAs, particularly miR-9, may be helpful in the diagnosis and clinical management of BTC.

Endoscopic diagnosis of extrahepatic bile duct carcinoma: Advances and current limitations

The accurate diagnosis of extrahepatic bile duct carcinoma is difficult, even now. When ultrasonography (US) shows dilatation of the bile duct, magnetic resonance cholangiopancreatography followed by endoscopic US (EUS) is the next step. When US or EUS shows localized bile duct wall thickening, endoscopic retrograde cholangiopancreatography should be conducted with intraductal US (IDUS) and forceps biopsy. Fluorescence in situ hybridization increases the sensitivity of brush cytology with similar specificity. In patients with papillary type bile duct carcinoma, three biopsies are sufficient. In patients with nodular or infiltrating-type bile duct carcinoma, multiple biopsies are warranted, and IDUS can compensate for the limitations of biopsies. In preoperative staging, the combination of dynamic multi-detector low computed tomography (MDCT) and IDUS is useful for evaluating vascular invasion and cancer depth infiltration. However, assessment of lymph nodes metastases is difficult. In resectable cases, assessment of longitudinal cancer spread is important. The combination of IDUS and MDCT is useful for revealing submucosal cancer extension, which is common in hilar cholangiocarcinoma. To estimate the mucosal extension, which is common in extrahepatic bile duct carcinoma, the combination of IDUS and cholangioscopy is required. The utility of current peroral cholangioscopy is limited by the maneuverability of the “baby scope”. A new baby scope (10 Fr), called “SpyGlass” has potential, if the image quality can be improved. Since extrahepatic bile duct carcinoma is common in the Far East, many researchers in Japan and Korea contributed these studies, especially, in the evaluation of longitudinal cancer extension.

Intraductal ultrasonography in the diagnosis of bile duct stones: when and whom?

BACKGROUND AND AIM

Biliary intraductal ultrasonography (IDUS) is highly sensitive in visualizing bile duct stones (BDS). Indications for IDUS, however, in cases of suspected BDS have not yet been established. The aim of the present study was to elucidate adequate indications for IDUS in cases that undergo endoscopic retrograde cholangiopancreatography (ERCP) due to suspected BDS.

METHODS

A total of 213 patients who were suspected of having BDS were included in this retrospective study. The patients were divided into two groups: Group A in which BDS was visualized by ERCP; and Group B in which BDS was demonstrated only by IDUS. Comparison between the groups was carried out.

RESULTS

ERCP successfully visualized BDS in 166 patients. Forty-seven patients underwent IDUS, which revealed BDS and biliary sludge in 12 and eight patients, respectively. The diameter of the largest stone was 13 ± 6 mm in Group A and 5 ± 1 mm in Group B (P < 0.001). The sensitivity, specificity, and accuracy of ERCP in the diagnosis of BDS were 93%, 100%, and 94%, respectively. The sensitivity was influenced by the size of BDS: 100% in cases of stones ≥ 8 mm in size, but 74% in those with stones < 8 mm. In cases with stones < 8 mm, the sensitivity was significantly affected by the bile duct diameter (≥ 12 mm vs < 12 mm, P < 0.05).

CONCLUSION

  When ERCP fails to visualize stones in patients with suspected BDS, IDUS is recommended, especially in those with a bile duct ≥ 12 mm in diameter.

New options of cholangioscopy

In the evaluation of biliary diseases, cholangioscopy is considered as complementary procedure to radiographic imaging. Direct visualization of the bile duct is the premier advantage of cholangioscopy over indirect imaging techniques. However, cholangioscopy has not gained wide acceptance because of several technical limitations such as scope fragility, impaired steerability, limited irrigation, and suction capabilities, as well as the need for two experienced endoscopists. Recent innovations such as the implementation of electronic video cholangioscopes and the development of single-operator systems facilitate the procedure, and promise to increase the diagnostic and therapeutic yield of cholangioscopy.

The role of endoscopic ultrasonography in the evaluation of pancreatico-biliary cancer

Accurate staging of pancreatico-biliary cancer is essential for surgical planning and for identification of locally advanced and metastatic disease that is incurable by surgery. The complex regional anatomy of the pancreatico-biliary system makes histologic diagnosis of malignancy at this region difficult. The ability to position the endoscopic ultrasound transducer at endoscopy in direct proximity to the pancreas and the bile duct, combined with the use of fine-needle aspiration, enables accurate preoperative staging of cancer, especially cancer too small to be characterized by CT or MRI. Endoscopic ultrasonography (EUS) identifies patients unlikely to be cured by surgery due to vascular invasion or regional nodal metastasis, thereby limiting procedure-related morbidity and mortality. This article focuses on the utility and recent advances of EUS in the evaluation of pancreatico-biliary cancer.

Are the echogenicities on intraductal ultrasonography really biliary microlithiasis?

BACKGROUND

Intraductal ultrasonography (IDUS) is a useful procedure for diagnosing microlithiasis in the bile duct but it is not easy to differentiate between tiny echogenicity and real microlithiasis. We compared the echogenicity seen on IDUS and the findings of bile microscopy (BM) of bile that was collected in the common bile duct (CBD) to determine whether the echogenicity seen on IDUS is real microlithiasis.

METHODS

This prospective study involved a total of 30 patients who experienced biliary pain (n = 11), acute cholecystitis (n = 11) or indeterminate pancreatitis (n = 8) without a filling defect or obstruction in the bile duct. IDUS was performed during endoscopic retrograde cholangiopancreatography (ERCP), followed by bile aspiration for BM. Endoscopic sphincterotomy (EST) was performed if definite echogenic materials were observed on IDUS.

RESULTS

Of the 30 patients, 23 (77%) had echogenic materials visible in the CBD on IDUS. Of these 23 patients, 13 (57%) were found to have biliary crystals by BM. The size of the echogenic materials was the only significant factor associated with BM positivity. Using the receiver operating curve, the optimal size of the echogenicity to differentiate real microlithiasis was 1.4 mm.

CONCLUSIONS

Optimal concordance between IDUS and BM was observed when the size of the microlithiasis was greater than 1.4 mm; under these conditions the sensitivity and specificity were 71% and 75%, respectively. This information may be useful when deciding whether to perform endoscopic sphincterotomy.

Intraductal ultrasonography combined with percutaneous transhepatic cholangioscopy for the preoperative evaluation of longitudinal tumor extent in hilar cholangiocarcinoma

BACKGROUND AND AIM

In hilar cholangiocarcinoma, an accurate assessment of preoperative resectability is important to optimize surgical resection. We investigated the accuracy of the combination of intraductal ultrasonography (IDUS) and percutaneous transhepatic cholangioscopy (PTCS) for evaluating longitudinal extent in hilar cholangiocarcinoma.

METHODS

Patients diagnosed with hilar cholangiocarcinoma underwent multidetector computed tomography (MDCT) and magnetic resonance cholangiography (MRC) for tumor staging and Bismuth type. Percutaneous transhepatic biliary drainage was performed at the left or right bile duct of the liver section that was anticipated to be preserved in the surgical treatment. After tract dilation, PTCS with cholangioscope-directed biopsy and IDUS were sequentially performed to evaluate Bismuth type. Surgical treatment was executed according to tumor staging and longitudinal tumor extent. Postoperative histological Bismuth types were compared to preoperative Bismuth types based on MDCT, MRC, PTCS with biopsy, and IDUS.

RESULTS

From June 2006 to November 2008, 25 patients with hilar cholangiocarcinoma were enrolled, with 20 of these patients evaluable. The accuracy of MDCT, MRC, PTCS with biopsy, and IDUS for the evaluation of Bismuth type was 80%, 84.2%, 90%, and 85.0%, respectively, in 20 patients, and 82.4%, 82.4%, 94.1%, and 88.2%, respectively, in 18 patients with Bismuth type IIIa, IIIb, or IV cancer. The accuracy of the combination of IDUS and PTCS with biopsy was 95% in 20 patients, and 100% in 18 with Bismuth type IIIa, IIIb, or IV cancer.

CONCLUSIONS

The combination of IDUS and PTCS with biopsy was highly accurate for assessing Bismuth type and may help in the identification of an optimal surgical plan for the treatment of hilar cholangiocarcinoma, especially in Bismuth type IIIa, IIIb, or IV.

Endoscopic ultrasonography can diagnose distal biliary strictures without a mass on computed tomography

AIM: To assess the diagnostic ability of endoscopic ultrasonography (EUS) for evaluating causes of distal biliary strictures shown on endoscopic retrograde cholangiopancreatography (ERCP) or magnetic resonance cholangiopancreatography (MRCP), even without identifiable mass on computed tomography (CT).

METHODS: The diagnostic ability of EUS was retrospectively analyzed and compared with that of routine cytology (RC) and tumor markers in 34 patients with distal biliary strictures detected by ERCP or MRCP at Dokkyo Medical School Hospital from December 2005 to December 2008, without any adjacent mass or eccentric thickening of the bile duct on CT that could cause biliary strictures. Findings considered as benign strictures on EUS included preservation of the normal sonographic layers of the bile duct wall, irrespective of the presence of a mass lesion. Other strictures were considered malignant. Final diagnosis of underlying diseases was made by pathological examination in 18 cases after surgical removal of the samples, and by clinical follow-up for > 10 mo in 16 cases.

RESULTS: Seventeen patients (50%) were finally diagnosed with benign conditions, including 6 “normal” subjects, while 17 patients (50%) were diagnosed with malignant disease. In terms of diagnostic ability, EUS showed 94.1% sensitivity, 82.3% specificity, 84.2% positive predictive value, 93.3% negative predictive value (NPV) and 88.2% accuracy for identifying malignant and benign strictures. EUS was more sensitive than RC (94.1% vs 62.5%, P = 0.039). NPV was also better for EUS than for RC (93.3% vs 57.5%, P = 0.035). In addition, EUS provided significantly higher sensitivity than tumor markers using 100 U/mL as the cutoff level of carbohydrate antigen 19-9 (94.1% vs 53%, P = 0.017). On EUS, biliary stricture that was finally diagnosed as malignant showed as a hypoechoic, irregular mass, with obstruction of the biliary duct and invasion to surrounding tissues.

CONCLUSION: EUS can diagnose biliary strictures caused by malignant tumors that are undetectable on CT. Earlier detection by EUS would provide more therapeutic options for patients with early-stage pancreaticobiliary cancer.

Intraductal ultrasonography (IDUS) for the diagnosis of biliopancreatic diseases

Intraductal ultrasonography (IDUS) is an imaging modality having unique characteristics and suitable for imaging of a narrow ductal cavity, its wall and the neighbouring structures. As IDUS uses high-frequency ultrasound (12-30MHz), its image quality is very high within approximately 2-cm range of radius. The bile duct and the pancreatic duct, therefore, are good targets for the assessment by IDUS. Biliopancreatic IDUS is mainly performed through the papilla of Vater in the same session as endoscopic retrograde cholangiopancreatography (ERCP). Biliary IDUS is possible through the percutaneous transhepatic route as well. Not many comparative studies on biliopancreatic IDUS have been published. Gallbladder IDUS as well as most pancreatic IDUS are still at the level of clinical research. Constant delineation of Oddi's sphincter with the improvement of instruments will expand the use of IDUS for the assessment of the papilla of Vater lesions.

Clinical application of intraductal ultrasound during endoscopic retrograde cholangiopancreatography

Intraductal ultrasound (IDUS) used during endoscopic retrograde cholangiopancreatography (ERCP) can facilitate reliable evaluation of biliary and pancreatic disorders. The smaller diameter, flexibility, and the image quality offered by IDUS devices makes them ideal for evaluating a variety of difficult biliary and pancreatic diseases, especially in undefined strictures, luminal filling defects, and ampullary neoplasms. This article examines the numerous possible roles for IDUS in the evaluation of biliary and pancreatic conditions, as well as in ampullary neoplasms. IDUS is a simple, easy to learn, and safe technique that should be considered an integral tool in the therapeutic endoscopist's armamentarium.

Evaluation of malignant and benign bile duct strictures by intraductal ultrasonography

AIM: To determine whether intraductal ultrasonography (IDUS) is of assistance in distinguishing benign from malignant biliary strictures.

METHODS: Sixty-seven patients (all were followed up for 12-36 mo) with biliopancreatic obstruction who underwent the examination of ERCP and IDUS from January 2006 to January 2007 were analyzed, and the difference of imaging diagnosis was compared and the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of IDUS were calculated.

RESULTS: Malignant strictures (37 patients) were confirmed histopathologically and benign stricture (30 patients) was confirmed based on negative pathology plus extended clinical follow-up. Sensitivity, specificity, positive predictive values, negative predictive values and accuracy of IDUS for malignant bile duct strictures were 89.2%, 77.4%, 82.5%, 88.9% and 85.1%.

CONCLUSION: Intraductal ultrasonography is safe and is of high value in differentiating benign from malignant biliary strictures.

Application of per oral cholangiopancreatoscopy in pancreatobiliary diseases

Pancreaticobiliary ductal diseases are largely investigated by indirect imaging techniques. Therefore, the pathology of up to 30% of cases remains undetermined. Cholangiopancreatoscopy allows direct visualization of ductal abnormalities with the ability to sample tissue and deliver a number of endotherapies. The technique can be broadly categorized into either two-operator or single-operator systems. Both systems provide important diagnostic information in the investigation of undetermined biliary or pancreatic strictures, intraductal papillary mucinous neoplasia, occult ductal malignant changes in patients with primary sclerosing cholangitis and occult intraductal stones in patients with complex biliary stone diseases. Therapeutically, cholangiopancreatoscopy-guided endotherapies provide a highly effective and safe alternative to surgery for patients with difficult extrahepatic and intrahepatic ductal stones that are not amenable to conventional endoscopic extraction by endoscopic retrograde cholangiopancreatography. The clinical application of cholangiopancreatoscopy, however, will be limited unless the technology is further refined to improve its durability, image quality, therapeutic capability and technical feasibility.

Cholangioscopy: where are we now?

PURPOSE OF REVIEW

The purpose of this review is to provide an update on current technologies and clinical indications for cholangioscopy. The review also focuses on techniques, challenges and limitations of available devices.

RECENT FINDINGS

Recent technological advances such as the introduction into clinical practice of video cholangioscopes as well as a single-operator semidisposable per oral cholangioscope are described. Novel clinical applications of cholangioscopy are also discussed.

SUMMARY

The past several years have witnessed the emergence of new technologies, including video and semidisposable cholangioscopes, which have increased the availability and utilization of cholangioscopes. Although the most common indications for this technique remain investigation of indeterminate cholangiographic findings and management of large bile duct stones, technological advances in the devices and available accessories will invariably lead to expanded indications in the future.

A comparison of hepatic mucinous cystic neoplasms with biliary intraductal papillary neoplasms

BACKGROUND & AIMS

There is controversy regarding the term biliary intraductal papillary neoplasms (IPN-B) and their pathology, which frequently are confused with hepatic mucinous cystic neoplasms (MCN). We aimed to summarize the clinicopathologic features of IPN-B and differentiate them from MCN.

METHODS

From January 1998 to December 2007, there were 19 patients with intrahepatic IPN-B and 13 patients with MCN who underwent surgical treatment at Zhongshan Hospital. Multiple demographic and clinicopathologic parameters were reviewed retrospectively and compared between the groups.

RESULTS

The mean ages of patients with IPN-B and MCN were 59.5 +/- 11.1 and 44.4 +/- 9.7 years, respectively (P = .0004); the male:female ratios also differed (11:8 vs 2:11; P = .028). Tumors were significantly smaller (6.0 vs 11.2 cm; P = .006) in patients with IPN-B than in those with MCN. More patients with IPN-B also had hepatolithiasis (47.4% vs 0%, P = .004); cholangiectasis and communication between the cyst and main bile duct were more frequent in patients with IPN-B than in those with MCN (P < .001). The IPN-B consisted of 4 subtypes--the gastric subtype was the least invasive. Malignant lesions were more common in patients with IPN-B than in those with MCN (78.9% vs 38.5%; P = .03). The overall 5-year survival rates of patients with IPN-B and MCN were 82% and 100%, respectively.

CONCLUSIONS

Intrahepatic IPN-B represents a distinct clinicopathologic entity that differs clinically, histologically, and radiologically from MCN. Curative resection has a favorable prognosis for patients with IPN-B, but further studies of its subtype are required.

Role of endoscopic ultrasound in the diagnosis and staging of pancreatic cancer

Early diagnosis of pancreatic cancer remains a difficult task, and multiple imaging tests have been proposed over the years. The aim of this review is to describe the current role of endoscopic ultrasound (EUS) for the diagnosis and staging of patients with pancreatic cancer. A detailed search of MEDLINE between 1980 and 2007 was performed using the following keywords: pancreatic cancer, endoscopic ultrasound, diagnosis, and staging. References of the selected articles were also browsed and consulted. Despite progress made with other imaging methods, EUS is still considered to be superior for the detection of clinically suspected lesions, especially if the results of other cross-sectional imaging modalities are equivocal. The major advantage of EUS is the high negative predictive value that approaches 100%, indicating that the absence of a focal mass reliably excludes pancreatic cancer. The introduction of EUS-guided fine needle aspiration allows a preoperative diagnosis in patients with resectable cancer, as well as a confirmation of diagnosis before chemoradiotherapy for those that are not. This comprehensive review highlighted the diagnostic capabilities of EUS including the newest refinements such as contrast-enhanced EUS, EUS elastography, and 3-dimensional EUS. The place of EUS-guided biopsy is also emphasized, including the addition of molecular marker techniques.