Results of a phase I-II study on intraductal confocal microscopy (IDCM) in patients with common bile duct (CBD) stenosis

Advanced endoscopy meets molecular diagnosis of cholangiocarcinoma

Cholangiocarcinoma remains an aggressive and deadly malignancy that is often diagnosed late. Intrinsic tumour characteristics and the growth pattern of cancer cells contribute to the challenges of diagnosis and chemoresistance. However, establishing an early and accurate diagnosis, and in some instances identifying targetable changes, has the potential to impact survival. Primary sclerosing cholangitis, a chronic cholangiopathy prodromal to the development of a minority of cholangiocarcinomas, poses a particular diagnostic challenge. We present our diagnostic and theranostic approach to the initial evaluation of cholangiocarcinomas, focusing on extrahepatic cholangiocarcinoma. This involves a multipronged strategy incorporating advanced imaging, endoscopic methods, multiple approaches to tissue sampling, and molecular markers. We also provide an algorithm for the sequential use of these tools.

In vivo detection of bile duct pre-cancer with endoscopic light scattering spectroscopy

Bile duct cancer is the second most common primary liver cancer, with most diagnoses occurring in the advanced stages. This leads to a poor survival rate, which means a technique capable of reliably detecting pre-cancer in the bile duct is urgently required. Unfortunately, radiological imaging lacks adequate accuracy for distinguishing dysplastic and benign biliary ducts, while endoscopic techniques, which can directly assess the bile duct lining, often suffer from insufficient sampling. Here, we report an endoscopic optical light scattering technique for clinical evaluation of the malignant potential of the bile duct. This technique employs an ultraminiature spatial gating fiber optic probe compatible with cholangioscopes and endoscopic retrograde cholangiopancreatography (ERCP) catheters. The probe allowed us to investigate the internal cellular composition of the bile duct epithelium with light scattering spectroscopy (LSS) and phenotypic properties of the underlying connective tissue with diffuse reflectance spectroscopy (DRS). In a pilot in vivo double-blind prospective study involving 29 patients undergoing routine ERCP procedures, the technique detected malignant transformation with 97% accuracy, showing that biliary duct pre-cancer can be reliably identified in vivo non-invasively.

Endoscopic management of perihilar cholangiocarcinoma

Endoscopic management for perihilar cholangiocarcinoma (PHCC) is evolving toward more accurate diagnosis and safer drainage. In imaging, it is important to diagnose the entire lesion using multidetector-row computed tomography to determine resectability and optimal surgical planning, followed by local diagnosis using endoscopic retrograde cholangiopancreatography. Video peroral cholangioscopy and probe-based confocal laser endomicroscopy have been newly introduced as diagnostic imaging methods and are being applied clinically. In transpapillary forceps biopsy for PHCC diagnosis, the location in the bile duct (for mapping biopsy) and the number of biopsy samples should be determined depending on resectability, the morphological type, and future surgical planning. Preoperative drainage has shifted from percutaneous transhepatic biliary drainage to endoscopic nasobiliary drainage given the possibility of seeding metastasis. In addition, considering potential patient discomfort from a nasal tube, the usefulness of the placement of a plastic stent above the papilla (inside stent) as a bridging therapy for surgery has been reported. For drainage of unresectable PHCC, the improved prognosis due to advances in chemotherapy has necessitated a strategy that accounts for reintervention. Thus, in addition to uncovered self-expandable metallic stents (SEMS), exchangeable slim fully covered SEMS and inside stents have started to be used. In addition to the conventional transpapillary approach, an endoscopic ultrasonography-guided approach has been introduced, and a combination of both methods has also been proposed. To improve the quality of life and prognosis of PHCC patients, endoscopists need to understand and be able to use the various methods of endoscopic management for PHCC.

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.

Current controversies and advances in the management of pancreatic adenocarcinoma

Pancreatic adenocarcinoma is a lethal disease with a mortality rate that has not significantly improved over decades. This is likely due to several challenges unique to pancreatic cancer. Most patients with pancreatic cancer are diagnosed at a late stage of disease due to the lack of specific symptoms prompting an early investigation. A small subset of patients who are diagnosed at an early stage have a better chance at survival with curative surgical resection, but most patients still succumb to the disease in a few years. The dismal overall prognosis is due to suspected micro-metastasis at an early stage. Due to this reason, there is a recent interest in treating all patients with pancreatic cancers with systemic therapy upfront (including the ones that are surgically resectable). This approach is still not the standard of care due to the lack of robust prospective data available. Recent advancements in treatment regimens of chemotherapy, radiation and immunotherapy have improved the overall short-term survival but the long-term survival still remains poor. Novel approaches in diagnosis and treatment have shown promise in clinical studies but long-term clinical data is lacking. The following manuscript presents an overview of the epidemiology, diagnosis, staging, recent advances, novel approaches and controversies in the management of pancreatic adenocarcinoma.

Probe-based confocal laser endomicroscopy for the diagnosis of pancreatic ductal structures

BACKGROUND AND AIM

The image-based diagnosis of pancreatic diseases can be difficult and requires pathological evaluation. Probe-based confocal laser endomicroscopy (pCLE) enables real-time observation of the microscopic tissue pattern of lesion and may be a useful assistance for the diagnosis. This study aimed to evaluate the feasibility and utility of pCLE for the diagnosis of pancreatic diseases.

METHODS

Thirty patients who underwent endoscopic retrograde cholangiopancreatography with pCLE for the evaluation of indeterminate pancreatic diseases from June 2015 to October 2018 were included in this study. The pCLE findings were interpreted according to the Miami Classification.

RESULTS

Among a total of 30 patients, 12, 10, 4, and 4 patients received the definitive diagnoses of pancreatic ductal adenocarcinoma (PDAC), main duct intrapapillary mucinous neoplasm, autoimmune pancreatitis, and chronic pancreatitis, respectively. The diagnostic accuracy of pCLE for PDAC and pancreatitis (96.7% and 93.3%, respectively) was higher than that of cytology (76.7% and 63.3%, respectively) (P = 0.0227 and 0.0048, respectively). The sensitivity of pCLE for PDAC was significantly higher (91.7%) than that of cytology (41.7%) (P = 0.0094). Moreover, the specificity of pCLE for pancreatitis was significantly higher than that of cytology (90.9% vs 50%; P = 0.0029). However, the diagnostic accuracies of pCLE and cytology for main duct intrapapillary mucinous neoplasm did not differ significantly (96.7% and 86.7%, respectively).

CONCLUSIONS

Probe-based confocal laser endomicroscopy may be effective for the diagnosis of pancreatic diseases as adjunct modality. It requires technical learning and further evaluation of its usefulness.

Diagnosis of Biliary Strictures Using Probe-Based Confocal Laser Endomicroscopy under the Direct View of Peroral Cholangioscopy: Results of a Prospective Study (with Video)

Background

The accurate diagnosis of biliary strictures remains problematic. The aim of the present study was to prospectively evaluate the clinical utility of probe-based confocal laser endomicroscopy (pCLE) under the direct view of peroral cholangioscopy (POCS) for the diagnosis of biliary strictures.

Methods

Consecutive patients with biliary strictures were included. We investigated sensitivity, specificity, and accuracy to diagnose malignancy for (1) ERCP alone, (2) POCS, (3) pCLE under the direct view of POCS, and (4) tissue sampling under the direct view of POCS.

Results

A total of 30 patients (17 with malignant lesions) were prospectively enrolled. (1) ERCP alone showed 88.2% sensitivity, 46.2% specificity, and 70% (95% confidence interval (CI), 52.1%–83.3%) accuracy. (2) POCS showed 100% sensitivity, 76.9% specificity, and 90% (95% CI, 74.4%–96.5%) accuracy. (3) pCLE under the direct view of POCS showed 94.1% sensitivity, 92.3% specificity, and 93.3% (95% CI, 78.7%–98.8%) accuracy. (4) Tissue sampling under the direct view of POCS showed 82.4% sensitivity, 100% specificity, and 90% (95% CI, 74.4%–96.5%) accuracy.

Conclusions

pCLE under the direct view of POCS provided highly accurate and sensitive characterization of biliary strictures and showed the potential for more diagnostic reliability and reduction of delays in diagnosis. This trial was registered at UMIN (registration number: UMIN000033801).

SAGES TAVAC safety and efficacy analysis confocal laser endomicroscopy

BACKGROUND

Confocal laser endomicroscopy (CLE) is a novel endoscopic adjunct that allows real-time in vivo histological examination of mucosal surfaces. By using intravenous or topical fluorescent agents, CLE highlights certain mucosal elements that facilitate an optical biopsy in real time. CLE technology has been used in different organ systems including the gastrointestinal tract. There has been numerous studies evaluating this technology in gastrointestinal endoscopy, our aim was to evaluate the safety, value, and efficacy of this technology in the gastrointestinal tract.

METHODS

The Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) Technology and Value Assessment Committee (TAVAC) performed a PubMed/Medline database search of clinical studies involving CLE in May of 2018. The literature search used combinations of the keywords: confocal laser endomicroscopy, pCLE, Cellvizio, in vivo microscopy, optical histology, advanced endoscopic imaging, and optical diagnosis. Bibliographies of key references were searched for relevant studies not covered by the PubMed search. Case reports and small case series were excluded. The manufacturer's website was also used to identify key references. The United States Food and Drug Administration (U.S. FDA) Manufacturer And User facility and Device Experience (MAUDE) database was searched for reports regarding the device malfunction or injuries.

RESULTS

The technology offers an excellent safety profile with rare adverse events related to the use of fluorescent agents. It has been shown to increase the detection of dysplastic Barrett's esophagus, gastric intraepithelial neoplasia/early gastric cancer, and dysplasia associated with inflammatory bowel disease when compared to standard screening protocols. It also aids in the differentiation and classification of colorectal polyps, indeterminate biliary strictures, and pancreatic cystic lesions.

CONCLUSIONS

CLE has an excellent safety profile. CLE can increase the diagnostic accuracy in a number of gastrointestinal pathologies.

Comparison of diagnostic efficacy between CLE, tissue sampling, and CLE combined with tissue sampling for undetermined pancreaticobiliary strictures: a meta-analysis

OBJECTIVE

The accurate diagnosis of undetermined pancreaticobiliary strictures remains challenging. Current ERCP-guided tissue sampling methods are of low sensitivity. Confocal laser endomicroscopy (CLE) is a new procedure and allows real optical biopsies that may improve the diagnosis of undetermined pancreaticobiliary strictures. The aim of this meta-analysis was to determine the diagnostic yield of CLE, tissue sampling, and CLE combined with tissue sampling for undetermined pancreaticobiliary strictures.

METHOD

Pubmed, Embase, and the Cochrane Library database were reviewed for relevant studies. Pooled estimates of sensitivity and specificity with 95% confidence intervals (CIs) were calculated using the random-effects meta-analysis model. The summary receiver-operating characteristic (SROC) curve was constructed, and the area under the receiver operating characteristic curve (AUC) was calculated.

RESULTS

Twelve studies involving 591 patients were enrolled in our analysis. The overall sensitivity and the specificity estimate of CLE for discriminating benign and malignant pancreaticobiliary strictures were 87% (95%CI, 83-91%) and 76% (95%CI, 70-81%), respectively. The AUC to assess the diagnostic efficacy was 0.8705. For tissue sampling, the overall sensitivity and the specificity estimate were 64% (95%CI, 57-70%) and 94% (95%CI, 90-97%), respectively. The AUC to assess the diagnostic efficacy was 0.8040. A combination of both methods increased the sensitivity (93%; 95%CI, 88-96%) with a specificity of 82% (95%CI, 74-89%). The AUC to assess the diagnostic efficacy was 0.9377. There was no publication bias by Deeks' Funnel Plot with p = .936.

CONCLUSIONS

Compared with tissue sampling, CLE may increase the sensitivity for the diagnosis of malignant pancreaticobiliary strictures. A combination of both can effectively diagnose malignant pancreaticobiliary strictures.

Improved classification of indeterminate biliary strictures by probe-based confocal laser endomicroscopy using the Paris Criteria following biliary stenting

BACKGROUND AND AIMS

Probe-based confocal laser endomicroscopy (pCLE) using the Miami Criteria has improved classification of indeterminate biliary strictures. However, previous biliary stenting may result in their misclassification as malignant strictures. Inflammatory criteria were added to form the Paris Classification to prevent this misclassification and reduce false positives. The aim of this study was to assess if the Paris Classification was more accurate than the Miami Classification in classifying indeterminate biliary strictures after biliary stenting.

METHODS

This was a retrospective observational study involving 21 patients with indeterminate biliary strictures from whom 27 pCLE video sequences were obtained (20 benign and seven malignant). Patients with and without prior biliary stenting underwent pCLE. Two investigators classified the strictures as malignant or benign using the Miami and Paris Classifications. Diagnostic accuracy, sensitivity (Se), and specificity (Sp) of endoscopic retrograde-guided pCLE were compared with final histopathology.

RESULTS

In those without biliary stenting, the Miami Criteria resulted in Se 88%, Sp 75%, positive predictive value (PPV) 64%, negative predictive value (NPV) 92%, and accuracy 79%, while the Paris Classification resulted in Se 63%, Sp 88%, PPV 71%, NPV 82%, and accuracy 79%. In those with prior biliary stenting, the Miami Criteria resulted in Se 88%, Sp 36%, PPV 23%, NPV 93%, and accuracy 45%, while the Paris Classification resulted in Se 63%, Sp 73%, PPV 31%, NPV 91%, and accuracy 71%. The kappa statistic was 0.56.

CONCLUSION

The Paris Classification improved specificity and accuracy of biliary stricture classification in those who had been previously stented and decreased the rate of misclassification of benign strictures as malignant.

Novel biomarkers and endoscopic techniques for diagnosing pancreaticobiliary malignancy

The UK incidence of pancreatic ductal adenocarcinoma is 9 per 100,000 population, and biliary tract cancer occurs at a rate of 1–2 per 100,000. The incidence of both cancers is increasing annually and these tumours continue to be diagnosed late and at an advanced stage, limiting options for curative treatment. Population-based screening programmes do not exist for these cancers, and diagnosis currently is dependent on symptom recognition, but often symptoms are not present until the disease is advanced. Recently, a number of promising blood and urine biomarkers have been described for pancreaticobiliary malignancy and are summarised in this review. Novel endoscopic techniques such as single-operator cholangioscopy and confocal endomicroscopy have been used in some centres to enhance standard endoscopic diagnostic techniques and are also evaluated in this review.

Identification of liver metastases with probe-based confocal laser endomicroscopy at two excitation wavelengths

BACKGROUND

Metastasis of colorectal cancer to the liver is the most common indication for hepatic resection in a western population. Incomplete excision of malignancy due to residual microscopic disease normally results in worse patient outcome. Therefore, a method aiding in the real time discrimination of normal and malignant tissue on a microscopic level would be of benefit.

MATERIAL AND METHODS

The ability of fluorescent probe-based confocal laser endomicroscopy (pCLE) to identify normal and malignant liver tissue was evaluated in an orthotopic murine model of colorectal cancer liver metastasis (CRLM). To maximise information yield, two clinical fluorophores, fluorescein and indocyanine green (ICG) were injected and imaged in a dual wavelength approach (488 and 660 nm, respectively). Visual tissue characteristics on pCLE examination were compared with histological features. Fluorescence intensity in both tissues was statistically analysed to elucidate if this can be used to differentiate between normal and malignant tissue.

RESULTS

Fluorescein (488 nm) enabled good visualisation of normal and CRLM tissue, whereas ICG (660 nm) visualisation was limited to normal liver tissue only. Fluorescence intensity in areas of CRLM was typically 53-100% lower than normal hepatic parenchyma. Using general linear mixed modelling and receiver operating characteristic analysis, high fluorescence intensity was found to be statistically more likely in normal hepatic tissue.

CONCLUSION

Real time discrimination between normal liver parenchyma and metastatic tissue with pCLE examination of fluorescein and ICG is feasible. Employing two (rather than a single) fluorophores allows a combination of qualitative and quantitative characteristics to be used to distinguish between hepatic parenchyma and CRLM. Lasers Surg. Med. 49:280-292, 2017. © 2016 Wiley Periodicals, Inc.

Imaging in pancreatic disease

Pancreatic diseases, chronic pancreatitis, pancreatic cancer and diabetes mellitus, taken together, occur in >10% of the world population. Pancreatic diseases, as with other diseases, benefit from early intervention and appropriate diagnosis. Although imaging technologies have given clinicians an unprecedented toolbox to aid in clinical decision-making, advances in these technologies and development of molecular-based diagnostic tools could enable physicians to identify diseases at an even earlier stage and, thereby, improve patient outcomes. In this Review, we discuss and identify gaps in the use of imaging techniques for the early detection and appropriate treatment stratification of various pancreatic diseases, including diabetes mellitus, acute and chronic pancreatitis and pancreatic cancer. Imaging techniques discussed are MRI, CT, PET and ultrasonography. Additionally, the identification of new molecular targets for imaging and the development of contrast agents that are able to give molecular information in noninvasive radionuclear imaging and ultrasonography are emerging areas of innovation that could lead to increased diagnostic accuracy and improved patient outcomes.

The Evolving Role of Pathology in New Developments, Classification, Terminology, and Diagnosis of Pancreatobiliary Neoplasms

Pancreatobiliary tract lesions are increasingly being discovered because of more sensitive imaging modalities. Magnetic resonance imaging has identified incidental pancreatic cysts in 13.5% of patients of progressively increasing age. Pancreatobiliary tissue is more accessible through endoscopic ultrasound and magnetic resonance imaging-guided biopsy procedures, and is now an integral part of pathologists' routine practice. Accordingly, several new tumor categories have been recently recognized, including intraductal tubulopapillary neoplasm, a new addition to tumoral intraepithelial neoplasms. Other entities have been reclassified, including the recent transition to 2-tiered grading of preinvasive neoplasms, as well as new perspectives on the distinctive biologic behavior of oncocytic intraductal papillary mucinous neoplasms (IPMNs) compared with other IPMN subtypes. This has led to proposals for revised staging of virtually every segment of the pancreatobiliary tree, with theranostic markers becoming an integral part of workup. Ki-67 is now an integral part of the classification of neuroendocrine tumors, with new definitions of "high-grade neuroendocrine carcinoma." Although bile duct brushings have opened new avenues for diagnosis, their sensitivity remains low and often requires concomitant fluorescent in situ hybridization to better define ambiguous cases. Various molecular pathways have been elucidated for pancreatic cysts, including KRAS for ductal neoplasia, GNAS for intestinal IPMNs, RNF3 for mucinous cysts, and VHL for serous cystic neoplasms, all key players in diagnostic workup. Integration of these updates into our understanding of pancreatobiliary disease requires active engagement of pathologists for appropriate specimen triage, judicious interpretation of results, and incorporation into reporting and staging. They also provide exciting opportunities for targeted therapy.

Probe-based confocal laser endomicroscopy for the diagnosis of undetermined biliary stenoses: A meta-analysis

BACKGROUND

Presently, both the accuracy and sensitivity for distinguishing biliary stenosis from benign to malignant are low. In recent articles, the probe-based confocal laser endomicroscopy (pCLE) showed a better sensitivity than traditional methods in diagnosing malignant biliary stenosis. Here, we conducted a meta-analysis to summarise the published literature.

METHODS

A systematic search for literature was conducted in the Medline, Embase and Cochrane Library databases published until November 2015. Further publications were found in the reference lists of the relevant articles. A quality assessment and data extraction were performed by two reviewers independently. A meta-analysis was performed to evaluate the diagnostic efficiency of a pCLE for discriminating benign and malignant biliary stenoses.

RESULTS

Eight studies involving 280 patients were included in the analysis. Significant heterogeneity in specificity was observed among the studies (Cochran's Q test=15.89, degrees of freedom [df]=7, P=0.0261 and I²=55.9%), while the heterogeneity in sensitivity was not obvious (Cochran's Q test=7.99, df=7, P=0.3334 and I²=12.4%). The area under the summary receiver operating characteristic (SROC) curve was 0.8968. The meta-regression and subgroup analysis indicated that the outlier was the source of heterogeneity. When analysed in the random-effects model, the pooled sensitivity, specificity, positive likelihood ratio (LR) and negative LR were 0.90 (0.84-0.94), 0.75 (0.66-0.83), 3.17 (2.18-4.61) and 0.17 (0.11-0.26), respectively. No significant publication bias was found in our research.

CONCLUSION

A pCLE is a valuable method for the differential diagnosis between malignant and benign biliary stenoses. However, a preferable diagnostic standard should be explored and improvements in specificity are required.

Confocal Laser Endomicroscopy in Gastrointestinal and Pancreatobiliary Diseases: A Systematic Review and Meta-Analysis

Confocal laser endomicroscopy (CLE) is an endoscopic-assisted technique developed to obtain histopathological diagnoses of gastrointestinal and pancreatobiliary diseases in real time. The objective of this systematic review is to analyze the current literature on CLE and to evaluate the applicability and diagnostic yield of CLE in patients with gastrointestinal and pancreatobiliary diseases. A literature search was performed on MEDLINE, EMBASE, Scopus, and Cochrane Oral Health Group Specialized Register, using pertinent keywords without time limitations. Both prospective and retrospective clinical studies that evaluated the sensitivity, specificity, or accuracy of CLE were eligible for inclusion. Of 662 articles identified, 102 studies were included in the systematic review. The studies were conducted between 2004 and 2015 in 16 different countries. CLE demonstrated high sensitivity and specificity in the detection of dysplasia in Barrett's esophagus, gastric neoplasms and polyps, colorectal cancers in inflammatory bowel disease, malignant pancreatobiliary strictures, and pancreatic cysts. Although CLE has several promising applications, its use has been limited by its low availability, high cost, and need of specific operator training. Further clinical trials with a particular focus on cost-effectiveness and medicoeconomic analyses, as well as standardized institutional training, are advocated to implement CLE in routine clinical practice.

Imaging hamster model of bile duct cancer in vivo using fluorescent L-glucose derivatives

Extrahepatic bile duct cancer (cholangiocarcinoma) has a poor prognosis. Since surgical resection is the only way to prolong the patient’s life, it is of critical importance to correctly determine the extent of lesions. However, conventional pre-operative assessments have insufficient spatial resolution for determining the surgical margin. A fluorescent contrast agent might provide a more precise measure to identify anomalies in biliary surface, when combined with probe-based confocal laser endomicroscopy (pCLE). We have previously shown that 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-l-glucose (2-NBDLG), a fluorescent derivative of l-glucose (fLG), is specifically taken up into spheroids consisting of cells showing heterogeneous nuclear-cytoplasm ratio, a feature of malignant cells in clinical settings. In addition, a combined use of 2-TRLG, a membrane-impermeable fLG, with 2-NBDLG visualized membrane integrity as well. We therefore explored in the present study the availability of the fLGs in vivo as a contrast agent for pCLE by using a hamster model of cholangiocarcinoma. Extrahepatic cholangiocarcinoma developed in mid common duct in ~20 % of the animals subjected to cholecystoduodenostomy with the ligation at the distal end of the common duct followed by injection of a carcinogen N-nitrosobis(2-oxopropyl)amine. After infusing bile duct with a solution containing 2-NBDLG and 2-TRLG, the lumen was surgically exposed and examined by pCLE. Fluorescence pattern characterized by bright spots and dark clumps was detected in the areas diagnosed with cholangiocarcinoma in later histopathology, whereas no such pattern was detected in control animals. These findings may form a basis for elucidating a potential availability of fLGs in imaging cholangiocarcinoma by pCLE.

High-resolution handheld rigid endomicroscope based on full-field optical coherence tomography

Full-field optical coherence tomography (FF-OCT) is a powerful tool for nondestructive assessment of biological tissue, i.e., for the structural examination of tissue in depth at a cellular resolution. Mostly known as a microscopy device for ex vivo analysis, FF-OCT has also been adapted to endoscopy setups since it shows good potential for in situ cancer diagnosis and biopsy guidance. Nevertheless, all the attempts to perform endoscopic FF-OCT imaging did not go beyond lab setups. We describe here, to the best of our knowledge, the first handheld FF-OCT endoscope based on a tandem interferometry assembly using incoherent illumination. A common-path passive imaging interferometer at the tip of an optical probe makes it robust and insensitive to environmental perturbations, and a low finesse Fabry-Perot processing interferometer guarantees a compact system. A good resolution (2.7 μm transverse and 6 μm axial) is maintained through the long distance, small diameter relay optics of the probe, and a good signal-to-noise ratio is achieved in a limited 100 ms acquisition time. High-resolution images and a movie of a rat brain slice have been recorded by moving the contact endoscope over the surface of the sample, allowing for tissue microscopic exploration at 20 m under the surface. These promising ex vivo results open new perspectives for in vivo imaging of biological tissue, in particular, in the field of cancer and surgical margin assessment.

Utilizing confocal laser endomicroscopy for evaluating the adequacy of laparoscopic liver ablation

Background

Laparoscopic liver ablation therapy can be used for the treatment of primary and secondary liver malignancy. The increased incidence of cancer recurrence associated with this approach, has been attributed to the inability of monitoring the extent of ablated liver tissue.

Methods

The feasibility of assessing liver ablation with probe‐based confocal laser endomicroscopy (CLE) was studied in a porcine model of laparoscopic microwave liver ablation. Following the intravenous injection of the fluorophores fluorescein and indocyanine green, CLE images were recorded at 488 nm and 660 nm wavelength and compared to liver histology. Statistical analysis was performed to assess if fluorescence intensity change can predict the presence of ablated liver tissue.

Results

CLE imaging of fluorescein at 488 nm provided good visualization of the hepatic microvasculature; whereas, CLE imaging of indocyanine green at 660 nm enabled detailed visualization of hepatic sinusoid architecture and interlobular septations. Fluorescence intensity as measured in relative fluorescence units was found to be 75–100% lower in ablated compared to healthy liver regions. General linear mixed modeling and ROC analysis found the decrease in fluorescence to be statistically significant.

Conclusion

Laparoscopic, dual wavelength CLE imaging using two different fluorophores enables clinically useful visualization of multiple liver tissue compartments, in greater detail than is possible at a single wavelength. CLE imaging may provide valuable intraoperative information on the extent of laparoscopic liver ablation. Lasers Surg. Med. 48:299–310, 2016. © 2015 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.

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.

Probe based confocal laser endomicroscopy of the pancreatobiliary system

AIM

To review applications of confocal laser endomicroscopy (CLE) in pancreatobiliary lesions and studies that assessed training and interpretation of images.

METHODS

A computerized literature search was performed using OVID MEDLINE, EMBASE, Cochrane library, and the ISI Web of Knowledge from 1980 to October 2014. We also searched abstracts from major meetings that included the Digestive Disease Week, Canadian Digestive Disease Week and the United European Gastroenterology Week using a combination of controlled vocabulary and text words related to pCLE, confocal, endomicroscopy, probe-based confocal laser endomicroscopy, and bile duct to identify reports of trials. In addition, recursive searches and cross-referencing was performed, and manual searches of articles identified after the initial search was also completed. We included fully published articles and those in abstract form. Given the relatively recent introduction of CLE we included randomized trials and cohort studies.

RESULTS

In the evaluation of indeterminate pancreatobiliary strictures CLE with ERCP compared to ERCP alone can increase the detection of cancerous strictures with a sensitivity of (98% vs 45%) and has a negative predictive value (97% vs 69%), but decreased the specificity (67% vs 100%) and the positive predictive value (71% vs 100%) when compared to index pathology. Modifications in the classification systems in indeterminate biliary strictures have increased the specificity of pCLE from 67% to 73%. In pancreatic cystic lesions there is a need to develop similar systems to interpret and characterize lesions based on CLE images obtained. The presence of superficial vascular network predicts serous cystadenomas accurately. Also training in acquiring and interpretation of images is feasible in those without any prior knowledge in CLE in a relatively simple manner and computer-aided diagnosis software is a promising innovation.

CONCLUSION

The role of pCLE in the evaluation of pancreatobiliary disorders might be better suited for those with an intermediate and low probability.

Use of probe-based confocal laser endomicroscopy (pCLE) in gastrointestinal applications. A consensus report based on clinical evidence

BACKGROUND

Probe-based confocal laser endomicroscopy (pCLE) provides microscopic imaging during an endoscopic procedure. Its introduction as a standard modality in gastroenterology has brought significant progress in management strategies, affecting many aspects of clinical care and requiring standardisation of practice and training.

OBJECTIVE

This study aimed to provide guidance on the standardisation of its practice and training in Barrett's oesophagus, biliary strictures, colorectal lesions and inflammatory bowel diseases.

METHODS

Initial statements were developed by five group leaders, based on the available clinical evidence. These statements were then voted and edited by the 26 participants, using a modified Delphi approach. After two rounds of votes, statements were validated if the threshold of agreement was higher than 75%.

RESULTS

Twenty-six experts participated and, among a total of 77 statements, 61 were adopted (79%) and 16 were rejected (21%). The adoption of each statement was justified by the grade of evidence.

CONCLUSION

pCLE should be used to enhance the diagnostic arsenal in the evaluation of these indications, by providing microscopic information which improves the diagnostic performance of the physician. In order actually to implement this technology in the clinical routine, and to ensure good practice, standardised initial and continuing institutional training programmes should be established.

Diagnosis and management of primary sclerosing cholangitis-perspectives from a therapeutic endoscopist

Primary sclerosing cholangitis (PSC) is a chronic, cholestatic liver condition characterized by inflammation, fibrosis, and destruction of the intra- and extrahepatic bile ducts. The therapeutic endoscopist plays a key role in the diagnosis and management of PSC. In patients presenting with a cholestatic profile, endoscopic retrograde cholangiopancreatography (ERCP) is warranted for a definite diagnosis of PSC. Dominant strictures of the bile duct occur in 36%-57% of PSC patients. Endoscopic balloon dilatation with or without stenting have been employed in the management of dominant strictures. In addition, PSC patients are at increased risk of developing cholangiocarcinoma with a 20% lifetime risk. Brush cytology obtained during ERCP and use of fluorescence in situ hybridization forms the initial diagnostic step in the investigation of patients with dominant biliary strictures. Our review aims to summarize the current evidence supporting the role of a therapeutic endoscopist in the management of PSC patients.

Endoscopic diagnosis of cholangiocarcinoma: From endoscopic retrograde cholangiography to bile proteomics

Cholangiocarcinoma (CCA) is the second most common primary liver cancer. In clinical practice, the diagnosis remains challenging and often requires endoscopic approaches. Endoscopic retrograde and percutaneous transhepatic cholangiography are the first-line endoscopic procedures for the evaluation of indeterminate bile duct strictures. Tissue acquisition via brush cytology and forceps biopsies allows the cytological and/or histological confirmation of the disease. Due to the low sensitivity of these techniques, repetitive examinations and/or alternative approaches are required. Cholangioscopy, endoscopic and intraductal ultrasound and confocal laser endomicroscopy are additional methods which can be applied for the diagnosis of CCA. Particularly, new experimental approaches like bile and urine proteomic analyses show promising results which have to be evaluated prospectively for further integration in diagnostic algorithms.

Laparoscopic manipulation of a probe-based confocal laser endomicroscope using a steerable intravascular catheter

Probe-based confocal laser endomicroscopy is an emerging imaging modality that enables visualization of histologic details during endoscopy and surgery. A method of guiding the probe with millimeter accuracy is required to enable imaging in all regions of the abdomen accessed during laparoscopy. On the basis of a porcine model of laparoscopic liver resection, we report our experience of using a steerable intravascular catheter to guide a probe-based confocal laser endomicroscope.

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.

Probe-based confocal laser endomicroscopy in the pancreatic duct provides direct visualization of ductal structures and aids in clinical management

BACKGROUND

Confocal endomicroscopy provides real-time evaluation of various sites and has been used to provide detailed endomicroscopic imaging of the biliary tree. We aimed to evaluate the feasibility and utility of probe-based confocal laser endomicroscopy of the pancreatic duct as compared to cytologic and histologic results in patients with indeterminate pancreatic duct strictures.

METHODS

Retrospective data on patients with indeterminate pancreatic strictures undergoing endoscopic retrograde cholangiopancreatography (ERCP) and confocal endomicroscopy were collected from two tertiary care centres. Real-time confocal endomicroscopy images were obtained during ERCP and immediate interpretation according to the Miami Classification was performed.

RESULTS

18 patients underwent confocal endomicroscopy for evaluation of pancreatic strictures from July 2011 to December 2012. Mean pancreatic duct size was 4.2mm (range 2.2-8mm). Eight cases were interpreted as benign, 4 as malignant, 4 suggestive of intraductal papillary mucinous neoplasms, and 2 appeared normal. Cytology/histopathology for 15/16 cases showed similar results to confocal endomicroscopy interpretation. Kappa coefficient of agreement between cyto/histopathology and confocal endomicroscopy was 0.8 (p=0.0001). Pancreatic confocal endomicroscopy changed management in four patients, changing the type of surgery from total pancreatectomy to whipple.

CONCLUSIONS

Confocal endomicroscopy is effective in assisting with diagnosis of indeterminate pancreatic duct strictures as well as mapping of abnormal pancreatic ducts prior to surgery.

Evaluation of pCLE in the bile duct: final results of EMID study : pCLE: impact in the management of bile duct strictures

INTRODUCTION

Pre-operative histology of bile duct stenosis is associated with low accuracy. Probe confocal laser endomicroscopy (pCLE) enables optical biopsy or in vivo histology. The definitive results of the EMID study are presented here, comparing optical biopsies with definitive histology.

AIMS AND METHODS

Sixty one patients with a biliary stricture without any previous histology were included (July 2007-May 2012). An endoscopic ultrasound (EUS) had to be conducted before the ERCP procedure. pCLE was done using CholangioFlex during the ERCP procedure. Results were compared to those of definitive histology obtained by biopsy or surgery in case of malignant lesions, and by surgery or 1-year follow-up in case of benign lesions.

RESULTS

Six patients were excluded because no definitive histology was available. There were 41 malignant lesions and 14 benign lesions. Sensitivity, specificity, PPV, NPV, and accuracy with combination of pCLE with endobiliary and EUS biopsies were 100, 71, 91, 100, and 93%, respectively (with a significant increase of accuracy compared with endobiliary and EUS biopsies without pCLE, p = 0.03). 19 patients had a biliary stricture without individualized mass (6 malignant lesions, 13 benign lesions). Sensitivity, specificity, PPV, NPV, and accuracy for pCLE were 83, 77, 62, 91, and 79%, respectively. Sensitivity, specificity, PPV, NPV, and accuracy for combination of pCLE with endobiliary and EUS biopsies were 100, 69, 60, 100, and 79%, respectively.

CONCLUSION

The addition of a pCLE procedure in the diagnostic histologic examination of a biliary stricture permits a significant increase in diagnostic reliability and allows for a VPN of 100%.

Pre- and post-training session evaluation for interobserver agreement and diagnostic accuracy of probe-based confocal laser endomicroscopy for biliary strictures

BACKGROUND AND AIM

Current diagnostic modalities for indeterminate biliary strictures offer low accuracy. Probe-based confocal laser endomicroscopy (pCLE) permits microscopic assessment of mucosal structures by obtaining real-time high-resolution images of the mucosal layers of the gastrointestinal tract. Previously, an interobserver study demonstrated poor to fair agreement even among experienced confocal endomicroscopy operators. Our objective was to assess interobserver agreement and diagnostic accuracy upon completion of a pCLE training session.

METHODS

Forty de-identified pCLE video clips of indeterminate biliary strictures were sent to five endoscopists at four tertiary care centers for scoring. Observers subsequently attended a teaching session by an expert pCLE user that included 20 training clips and rescored the same pCLE video clips, which were randomized and renumbered.

RESULTS

Pre-training interobserver agreement for all observers was 'fair' (Κ: 0.31, P-value: <0.0001) and diagnostic accuracy was 72% (55-80%). Post-training interobserver agreement for all observers was 'substantial' (Κ: 0.74, P-value: <0.0001) and diagnostic accuracy was 89% (80-95%). Using a paired t-test, we observed an increase of 17% (95% CI 7.6-26.4) in post-training diagnostic accuracy (t = 5.01, df = 4, P-value 0.007).

CONCLUSIONS

Interobserver agreement and diagnostic accuracy improved after observers underwent training by an expert pCLE user with a specific sequence set. Users should participate in such training programs to maximize diagnostic accuracy of pCLE evaluation.

Endomicroscopy in bile duct: Inflammation interferes with pCLE applied in the bile duct: A prospective study of 54 patients

BACKGROUND

The preoperative diagnosis of biliary stenosis is associated with low accuracy. As a consequence, probe-based confocal laser endomicroscopy (pCLE), an in-vivo histological imaging technique, was applied in the bile duct. The aim of this study was to establish whether previous inflammation of the bile duct affects confocal interpretation. The findings from pCLE were compared in two groups of patients: those in whom there had been no cholangitis nor stenting and those in whom stents had been used and subsequently retrieved or who had suffered cholangitis.

PATIENTS AND METHODS

pCLE was performed on 54 patients (mean age 66 years; 31 men, 23 women) from September 2008 to July 2011. Patients were divided in two groups: group 1: 39 patients who had not undergone a biliary procedure in the month preceding the pCLE procedure; and group 2: 15 patients who had undergone stent placement or presented with cholangitis in the month preceding the pCLE procedure. Endoscopic and pCLE data were collected prospectively. pCLE results were compared to benchmark histology (surgery, endoultrasonography, percutaneous biopsy). Patients with a benign stricture who did not undergo operation were followed for 1 year. pCLE images of the bile duct were obtained during endoscopic retrograde cholangiopancreatography procedures. pCLE images were interpreted prospectively using the Miami classification in vivo and in real time.

RESULTS

In group 1, sensitivity, specificity, and accuracy were 88, 83, and 87%, respectively. In group 2, sensitivity, specificity, and accuracy were 75, 71, and 73%, respectively. Diagnostic accuracy of pCLE was lower when applied to group 2 (p < 0,001). The investigation is less reliable in bile ducts affected by inflammation from cholangitis or previous stenting.

CONCLUSIONS

Inflammatory lesions of the bile duct interfere with interpretation of pCLE. A refined pCLE description of inflammatory lesions should improve accuracy of pCLE in bile duct stenosis.

Sensitivity of alternative testing for pancreaticobiliary cancer: a 10-y review of the literature

BACKGROUND

Biliary strictures present a diagnostic challenge to differentiate benign disease from hepatopancreaticobiliary (HPB) malignancies. Endoscopic retrograde cholangiopancreatography cytology is commonly performed in these patients; however, its sensitivity for diagnosis of HPB malignancy is poor (41.6%). Many adjunctive tests have been investigated to improve the sensitivity of HPB biopsies. To determine the best tests available, however, we reviewed the literature and performed a comparative analysis of all recently investigated tests and their sensitivities.

METHODS

A PubMed search identified articles published between 2003 and 2014, describing alternate methods for diagnosing HPB malignancies, reported sensitivity, final pathology, and had data available online. Meta-analysis was conducted for tests with multiple articles. Tests with the highest sensitivity and specificities were reported.

RESULTS

A total of 77 studies were identified. Meta-analysis was performed on the sensitivity of EUS-FNA (74.2%), fluorescence in situ hybridization (54.2%), immunostain of insulin-like growth factor 2 mRNA-binding Protein 3 (IMP3; 80.4%), IMP3 + cytology (86.4%), K homology domain containing protein overexpressed in cancer (KOC; 85.9%), S100P (77.8%), serum CA19-9 (69.3%), and K-ras mutations (47.0%) to detect malignancy. Ultimately, 12 tests were identified with superior sensitivity (85.3%-100%) and specificities (81.6%-100%) including stricture scrapping, brush sectioning, IMP3 stain + cytology, IMP3+S100A4, bile carcinoembryonic cell adhesion molecule 6 protein (±CA19-9), bile micro RNA (miRNA)-135b, serum miRNA-RNU2-1f, serum miRNA-21 (+CA19-9), peripheral blood mononuclear cells miRNA-27a-3p (+CA19-9), serum miRNA-16 + miRNA-196a (+CA19-9), peripheral blood mononuclear cells mRNAs h-TERT + CK20 + CEA + C-MET.

CONCLUSIONS

We recommend immunostaining with a panel of IMP3+KOC + S100A4 + cytology to achieve maximum sensitivity and specificity from HPB biopsies. One biliary protein (carcinoembryonic cell adhesion molecule 6) and several RNAs (bile and blood) offer exceptional sensitivity and specificity and should be tested prospectively in larger populations. Overall, this review identifies several tests to improve the sensitivity of diagnostic algorithms to identify HPB malignancies.

Confocal Laser Endomicroscopy in the Detection of Head and Neck Precancerous Lesions

Objective

This study aimed to determine the feasibility of using probe-based confocal laser endomicroscopy (pCLE) in the diagnostic differentiation of non-neoplastic lesions from precancerous and cancerous lesions of head and neck patients.

Study Design

Diagnostic test evaluation.

Setting

Louisiana State University Health Shreveport.

Subjects and Methods

Intravenous injection of fluorescein was given to patients with precancerous and cancerous head and neck lesions (n = 21) followed by the use of a 1.8-mm GastroFlex probe in the oral cavity with subsequent biopsies of selected areas. Probe-based confocal laser endomicroscopy images were compared to histologic evaluation of visualized sites using sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV).

Results

The dorsal surface of the tongue was not well visualized. The remaining nonkeratinized subsites, including the buccal mucosa, floor of mouth, and ventral tongue, were well visualized. Diagnoses based on pCLE images correlated well with the gold standard diagnoses based on tissue histology. The overall sensitivity for diagnosis of dysplasia versus nondysplasia was 80.0% (95% confidence interval [CI], 62.0-98.0), specificity and PPV were 100%, and the NPV was 80.0% (95% CI, 60.0-100.0). The overall specificity, sensitivity, PPV, and NPV for pCLE diagnosis of carcinoma versus nondysplasia were 100%. The overall sensitivity for diagnosis of carcinoma versus dysplasia was 85.7% (95% CI, 73.0-99.0), specificity and PPV were 100%, and the NPV was 80.0% (95% CI, 60.0-100.0).

Conclusion

The pCLE is a promising method for differentiating between nondysplastic, precancerous, and cancerous lesions of the head and neck.

Novel endoscopic approaches in the diagnosis and management of biliary strictures

Indeterminate bilary strictures present the clinician with a wide differential diagnosis. Histological confirmation is usually required for treatment, but tissue acquisition remains challenging. Novel developments in endoscopic technology, such as single operator cholangioscopy and confocal endomicroscopy, have led to improvements in diagnostic accuracy in recent years. In patients with non-resectable malignant biliary obstruction, effective biliary decompression improves symptoms and enables patients to undergo palliative therapies. Improvements in endoscopic techniques, biliary stents and the development of local ablative techniques have led to further improvements in stent patency and survival in these patients. In this article, we review emerging diagnostic and therapeutic techniques for the endoscopic management of indeterminate biliary strictures.

ERCP with probe-based confocal laser endomicroscopy for the evaluation of dominant biliary stenoses in primary sclerosing cholangitis patients

BACKGROUND AND STUDY AIM

The incidence of cholangiocarcinoma (CCA) in primary sclerosing cholangitis (PSC) ranges between 7 and 14 %. Despite using multiple tissue sampling modalities, detection of CCA remains a challenge. Probe-based confocal laser endomicroscopy (pCLE) has been utilized to visualize subepithelial biliary mucosa in patients with indeterminate strictures. We assessed the technical feasibility and operating characteristics of pCLE in a cohort of PSC patients with dominant biliary strictures (DS).

PATIENTS AND METHODS

This was a chart review of a prospectively maintained database at a single tertiary referral center of 15 PSC patients with 21 dominant stenoses undergoing pCLE. A data collection sheet included demographics, ERCP, cholangioscopy, pCLE (Miami criteria), tissue sampling results, and follow-up to 12 months or liver transplantation. Operating characteristics for pCLE and ERCP tissue sampling were calculated.

RESULTS

Sufficient visualization of DS by pCLE was achieved in 20/21 (95 %). pCLE sensitivity, specificity, PPV, and NPV were 100 % (95 % CI 19.3-100 %), 61.1 % (95 % CI 35.8-82.6 %), 22.2 % (95 % CI 3.5-59.9 %), and 100 % (95 % CI 71.3-100 %), respectively, in detecting neoplasia. In comparison, concomitant tissue sampling yielded sensitivity, specificity, PPV, and NPV of 0 % (95 % CI 0-80.7 %), 94.4 % (95 % CI 72.6-99.1 %), 0 % (95 % CI 0-83.5 %), and 89.5 % (95 % CI 66.8-98.4 %), respectively.

CONCLUSIONS

pCLE achieves a high technical success rate in patients with PSC and DS. This single center, small series, suggests that pCLE may have a high sensitivity and negative predictive value to exclude neoplasia. If verified in larger prospective studies, the technology may be utilized to risk stratify dominant strictures in patients with PSC.

Technologies for imaging the normal and diseased pancreas

The prognosis is poor for most patients with pancreatic cancer, chronic pancreatitis, or other pancreatic diseases. Advances in pancreatic imaging could help identify these diseases at earlier stages, when they are easier to treat. Radiographic imaging and endoscopic imaging of the pancreas have progressed from the abdominal roentogram and endoscopic retrograde pancreatography to multi-detector computed tomography, magnetic resonance cholangiopancreatography, endoscopic ultrasonography, and pancreatoscopy. These technologies have improved the diagnosis and treatment of benign disease but have not significantly increased our ability to detect early-stage disease or affect outcomes of patients with pancreatic cancer or chronic pancreatitis. Advances in endoscopic imaging and molecular-based radiographic tests could allow physicians to identify pancreatic lesions and their precursors at earlier stages. Furthermore, research studies that include these tools could improve our understanding of disease pathogenesis and identify diagnostic markers and therapeutic targets. We review endoscopic imaging modalities, focusing on new endoscopic and molecular-based radiographic imaging tests that have the potential to substantially improve diagnosis and treatment of pancreatic disease.

Refined probe-based confocal laser endomicroscopy classification for biliary strictures: the Paris Classification

BACKGROUND

Most modalities for tissue confirmation during endoscopic retrograde cholangiopancreatography (ERCP) suffer from low sensitivity and poor diagnostic accuracy. Probe-based confocal laser endomicroscopy (pCLE) was prospectively evaluated in a multicenter registry including 102 patients with indeterminate strictures and demonstrated excellent sensitivity (98 %). Yet, several false-positive cases were induced by benign inflammatory conditions resulting in a specificity of 67 %.

AIMS

To evaluate the diagnostic performance of pCLE for the diagnosis of indeterminate biliary stricture; and to propose interpretation criteria for benign inflammatory conditions to reduce the number of false positives.

METHODS

Sixty cases from the prospective registry were reviewed retrospectively (27 malignant, 33 benign) by a panel of three biliary endoscopists. Each case's clinical history, ERCP impression, and corresponding pCLE sequences was used to score image quality, propose presumptive diagnoses, and rate level of diagnostic confidence.

RESULTS

Using the Miami Classification (MC), the overall accuracy in retrospectively diagnosing malignancy in those 60 cases was 85 versus 78 % for the prospective analysis, reducing the number of false positives from 12 to 8. A second review of the false-positive cases' pCLE sequences (benign inflammatory) helped refine the existing classification by identifying four descriptive criteria specific to benign inflammatory conditions (Paris Classification): Vascular congestion, dark granular patterns with scales, increased inter-glandular space, and thickened reticular structure.

CONCLUSIONS

The Paris Classification is a refinement of the existing Miami Classification to improve the accuracy of pCLE for diagnosing benign inflammatory strictures. Prospective multicenter studies are needed to further validate this refined classification criteria.

Probe-based confocal laser endomicroscopy for the diagnosis of indeterminate biliary strictures

PURPOSE OF REVIEW

Indeterminate biliary strictures frequently present as a diagnostic conundrum given the suboptimal accuracy rates of current sampling techniques. They are defined as those observed on at least one imaging modality with negative cytopathologic evaluation on previous sampling attempts (brushings and/or endobiliary biopsy) during endoscopic retrograde cholangiopancreatography in the absence of an alternative cause. Various novel sampling techniques (cholangioscopy-directed biopsies) and advanced imaging technologies (cholangioscopy, confocal laser microscopy, and narrow band imaging) have been described in the evaluation of indeterminate biliary strictures. Probe-based confocal laser microscopy (pCLE) is at the forefront of these techniques and provides microscopic information in real time incorporating dynamic information such as blood flow, cellular architecture, contrast uptake, and leakage.

RECENT FINDINGS

Standardized classification of pCLE findings of biliary strictures has been proposed. Initial observational studies have reported encouraging data specifically with regard to the sensitivity and negative predictive value of the pCLE findings in diagnosing malignancy.

SUMMARY

Initial results are encouraging with the eventual hope of expediting malignancy detection to enhance management options of patients with biliary malignancy. Further, if pCLE findings are benign, this can reassure both patient and provider. Multicenter prospective trials are underway to further validate criteria and define the role of this technology compared with conventional tissue sampling techniques in the diagnostic algorithm for indeterminate biliary strictures.

Interobserver agreement for confocal imaging of ampullary lesions: a multicenter single-blinded study

BACKGROUND

Malignant ampullary lesions can be difficult to classify by endoscopy alone. Probe-based confocal laser endomicroscopy (pCLE) permits in vivo assessment of mucosal structures in the gastrointestinal tracts in the real time.

AIM

The objective of this pilot multicenter study was to assess the interobserver agreement and variance in interpretation of pCLE of ampullary lesions.

METHODS

Twelve pCLE video clips of ampullary lesions were distributed to 6 gastrointestinal specialists at 5 medical centers, blinded to final pathologic results. Six variables were assessed for interobserver agreement using κ statistics. Variables included an epithelial outer border with irregular thickness, dark epithelium without discernable individual cells, heterogenously distributed elongated crypts, reduced number of goblet cells, neovascularization, and final diagnosis.

RESULTS

The overall interobserver agreement for all observers was poor to slight for all variables (κ=0.02, 0.05, -0.01, 0.04, 0.018) except for the first variable with fair degree of agreement (κ=0.27). On the basis of experience, 3 observers were classified as less experienced, whereas 3 were classified as most experienced. Upon stratification, the less experienced observers had poor interobserver agreement for all variables, except 1. The most experienced observers had poor agreement for 2 variables, slight agreement for 3 variables, and fair agreement for the final diagnosis variable.

CONCLUSIONS

The overall interpersonal agreement on pCLE for ampullary lesions was poor. The interobserver agreement was not substantially improved for experienced raters. Further standardization of pCLE image criteria is needed for ampullary lesions. Standardized training may improve interrater reliability to an acceptable level.

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.

Asia-Pacific consensus recommendations for endoscopic and interventional management of hilar cholangiocarcinoma

Hilar cholangiocarcinoma (HCCA) is one of the most common types of hepatobiliary cancers reported in the world including Asia-Pacific region. Early HCCA may be completely asymptomatic. When significant hilar obstruction develops, the patient presents with jaundice, pale stools, dark urine, pruritus, abdominal pain, and sometimes fever. Because no single test can establish the definite diagnosis then, a combination of many investigations such as tumor markers, tissue acquisition, computed tomography scan, magnetic resonance imaging/magnetic resonance cholangiopancreatography, endoscopic ultrasonography/intraductal ultrasonography, and advanced cholangioscopy is required. Surgery is the only curative treatment. Unfortunately, the majority of HCCA has a poor prognosis due to their advanced stage on presentation. Although there is no survival advantage, inoperable HCCA managed by palliative drainage may benefit from symptomatic improvement. Currently, there are three techniques of biliary drainage which include endoscopic, percutaneous, and surgical approaches. For nonsurgical approaches, stent is the most preferred device and there are two types of stents i.e. plastic and metal. Type of stent and number of stent for HCCA biliary drainage are subjected to debate because the decision is made under many grounds i.e. volume of liver drainage, life expectancy, expertise of the facility, etc. Recently, radio-frequency ablation and photodynamic therapy are promising techniques that may extend drainage patency. Through a review in the literature and regional data, the Asia-Pacific Working Group for hepatobiliary cancers has developed statements to assist clinicians in diagnosing and managing of HCCA. After voting anonymously using modified Delphi method, all final statements were determined for the level of evidence quality and strength of recommendation.

Endomicroscopy of the pancreaticobiliary system

It is often difficult to accurately differentiate between benign and malignant pancreaticobiliary strictures, and some are interpreted as indeterminate despite ERCP, EUS, or radiological imaging techniques, thereby making it difficult for the clinician to make appropriate management decisions. Probe-based confocal laser endomicroscopy (pCLE) is an innovative imaging tool integrating real-time in vivo imaging of these difficult-to-interpret strictures in the pancreaticobiliary system during endoscopy. Recent studies of endomicroscopy have shown a promising role with improved accuracy in distinguishing these lesions, thus paving the way for future research addressing improving precise interpretation, training, and long long-term impact.

Progress in molecular imaging in endoscopy and endomicroscopy for cancer imaging

Imaging is an essential tool for effective cancer management. Endoscopes are important medical instruments for performing in vivo imaging in hollow organs. Early detection of cancer can be achieved with surveillance using endoscopy, and has been shown to reduce mortality and to improve outcomes. Recently, great advancements have been made in endoscopic instruments, including new developments in optical designs, light sources, optical fibers, miniature scanners, and multimodal systems, allowing for improved resolution, greater tissue penetration, and multispectral imaging. In addition, progress has been made in the development of highly-specific optical probes, allowing for improved specificity for molecular targets. Integration of these new endoscopic instruments with molecular probes provides a unique opportunity for significantly improving patient outcomes and has potential to further improve early detection, image guided therapy, targeted therapy, and personalized medicine. This work summarizes current and evolving endoscopic technologies, and provides an overview of various promising optical molecular probes.

Interpretation of probe-based confocal laser endomicroscopy of indeterminate biliary strictures: is there any interobserver agreement?

BACKGROUND

Probe-based confocal laser endomicroscopy (pCLE) has enabled in vivo histopathology by obtaining high resolution images of the mucosal layers of the gastrointestinal tract. For indeterminate bile duct strictures, biopsy, cytologic brushing and needle aspiration have low levels of diagnostic accuracy.

AIM

The objective of this multi-center pilot study was to assess the interobserver agreement in interpretation of pCLE imaging.

METHODS

Twenty-five de-identified pCLE video clips of indeterminate biliary strictures were sent to 6 observers at 5 institutions. Miami Classification was used to standardize image interpretation. Seven variables were assessed for interobserver agreement using the Fleiss kappa statistic which included: presence of thick (>20 μm) or thin (<20 μm) dark or white bands, dark clumps, epithelium including glandular structures, interstitial fluorescein leakage, ease of interpretation, and final diagnosis. Based on operator experience, observers were categorized into 3 categories of experience (Category 1: 0-10; Category 2: 11-20; Category 3: >21 cases).

RESULTS

Upon stratification, Category 1 interobserver agreement ranged from "Poor" to "Fair" (κ = 0.277, κ = -0.079, κ = -0.025, κ = -0.066, κ = 0.128, κ = 0.088), and for the final diagnosis variable, the agreement was slight (κ = 0.033). Category 2 and 3 interobserver agreement ranged from "Poor" to "Fair" (κ = 0.211, κ = 0.181, κ = 0.347, κ = 0.238, κ = -0.050, κ = 0.092), and for the final diagnosis variable, the agreement was slight (κ = 0.195).

CONCLUSION

The overall interobserver agreement for pCLE image interpretation in indeterminate biliary strictures ranges from poor to fair. Interpretation criteria as well as training require further standardization toward improving inter-rater reliability.

Endoscopic management of benign biliary strictures

Endoscopic retrograde cholangiopancreatography (ERCP) is the first-line management in most situations when a benign biliary stricture is suspected. Although management principles are similar in all subgroups, the anticipated response rates, need for ancillary medical and endoscopic approaches, and use of less proven strategies vary between differing causes. Exclusion of malignancy should always be a focus of management. Newer endoscopic techniques such as endoscopic ultrasound, cholangioscopy, confocal endomicroscopy, and metal biliary stenting are increasingly complementing traditional ERCP techniques in achieving long-term sustained stricture resolution. Surgery remains a definitive management alternative when a prolonged trial of endoscopic therapy does not achieve treatment goals.

Endoscopic diagnosis of biliary tract disease

PURPOSE OF REVIEW

Endoscopic diagnosis of biliary disease is challenging due to difficulties in access, visualization, and sampling. Recent advances in endoscopic technology, ancillary diagnostic methods, and our understanding of autoimmune pancreatitis (AIP) and IgG4-related cholangitis (IRC) have led to improvements in the endoscopic diagnosis of pancreaticobiliary disease.

RECENT FINDINGS

Single-operator cholangioscopy overcomes several of the limitations of mother-baby cholangioscopy enhancing the diagnostic accuracy in indeterminate pancreaticobiliary disease. Probe-based confocal laser endomicroscopy has been recently shown to provide a significantly higher accuracy for the diagnosis of malignant biliary strictures than achieved by endoscopic retrograde cholangiopancreatogram and standard tissue acquisition, and has the potential to develop into a useful adjunct method of cholangioscopy. Fluorescence in-situ hybridization increases the sensitivity of routine brush cytology without compromising specificity in patients with indeterminate biliary strictures. The diagnosis of AIP/IRC remains challenging. The recently published international consensus criteria for AIP have included data on the potential diagnostic utility of endoscopic retrograde pancreatogram and endoscopic ampullary biopsies.

SUMMARY

Recent technical advances as well as ancillary diagnostic methods have improved the diagnostic accuracy of conventional endoscopic techniques. Future refinement of endoscopic methods may further improve diagnostic approaches to biliary disease.

A review on the use of confocal laser endomicroscopy in the bile duct

Background. Current methods to diagnose malignant biliary strictures are of low sensitivity. Probe-based confocal laser endomicroscopy (pCLE) is a new approach that can be used to evaluate in vivo histopathology of the GI tract. This paper is of studies evidencing pCLE's application in the diagnosis of indeterminate biliary strictures. Methods. This paper examined peer-reviewed studies conducted between January 2000 and November 2011. A PubMed search for relevant articles was performed using the following keywords:“pCLE”, “confocal”, “endomicroscopy”, “probe-based confocal laser endomicroscopy”, “and “bile duct”. Further individual review was done to assess the screened articles' relevance to the topic. Results. After individual review, 6 studies were included; with a cumulative sample size of 165, with 75 subjects identified as having a malignancy. These studies included tertiary care centers in Germany, France, and USA, including one multicenter trial. 3 studies assessed pCLE's specificity (range 67%–88%) ,sensitivity (range 83%–98), and accuracy (range 81%–86%). Conclusion. Confocal endomicroscopy is a novel and promising modality for the biliary tree. Further studies need to be conducted both to establish its usefulness for the diagnosis of indeterminate biliary strictures and to understand the histological meaning of the imaging patterns that are observed.