Evaluation of the pancreaticobiliary ductal systems by intraductal US

Role of ERCP in Benign Biliary Strictures

Benign biliary strictures (BBS) can be associated with several causes, with postoperative and inflammatory strictures representing the most common ones. Endoscopy represents nowadays the first-line treatment in the management of BBS. Endoscopic balloon dilatation, plastic stents placement, fully covered metal stent placement, and magnetic compression anastomosis are the endoscopic techniques available for the treatment of BBS. The aim of this study is to perform a review of the literature to assess the role of endoscopy in the management of BBS and to evaluate the application of the different procedures in the different clinical settings.

Cholangiocarcinoma Evaluation via Imaging and Artificial Intelligence

BACKGROUND

Cholangiocarcinoma (CCA) is a relatively rare malignant biliary system tumor, and yet it represents the second most common primary hepatic neoplasm, following hepatocellular carcinoma. Regardless of the type, location, or etiology, the survival prognosis of these tumors remains poor. The only method of cure for CCA is complete surgical resection, but part of patients with complete resection are still subject to local recurrence or distant metastasis.

SUMMARY

Over the last several decades, our understanding of the molecular biology of CCA has increased tremendously, diagnostic and evaluative techniques have evolved, and novel therapeutic approaches have been established. Key Messages: This review provides an overview of preoperative imaging evaluations of CCA. Furthermore, relevant information about artificial intelligence (AI) in medical imaging is discussed, as well as the development of AI in CCA treatment.

Evaluation of Intravascular Ultrasound Catheter-Based Transducers Using the Resolution Integral

Intravascular ultrasound (IVUS) catheters are a specialist imaging modality used in the assessment of cardiovascular disease. The ultrasound transducer may either be of single-element mechanical or phased-array design. Because of their design and operating frequencies (10-45 MHz), evaluation of the imaging performance is not possible with commercially available ultrasound test objects. An existing test object, the Edinburgh Pipe Phantom, was modified to allow measurement of resolution integral (R), depth of field (Lr) and characteristic resolution (Dr) of IVUS catheters. In total, seven IVUS catheters, from two manufacturers and of both single-element mechanical and phased-array design, were tested to provide a measure of performance over different frequencies and technologies. Measurements of R for the tested IVUS catheters ranged from 11.9 to 18.8. The modified Edinburgh Pipe Phantom therefore allows catheter-based ultrasound probes to be evaluated scientifically and their performance to be seen in relation to other similar ultrasound technologies such as pre-clinical ultrasound and endoscopic ultrasound.

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.

Advances in the investigation of obstructive jaundice

The causes of obstructive jaundice are varied, and timely, accurate methods of investigation are essential to avoid the development of complications. Imaging, invasive or non-invasive, should be carefully selected depending on the suspected underlying pathology in order to determine the degree and level of obstruction along with tissue acquisition and staging where relevant. Several imaging techniques will also allow subsequent therapeutic interventions to be carried out. This article reviews advances in the investigation of obstructive jaundice, highlighting recent developments, many of which at present remain restricted to large centres of expertise, but are likely to become more widespread in use as research progresses and local experience continues to improve.

The role of intraductal US in the management of idiopathic recurrent pancreatitis without a definite cause on ERCP

BACKGROUND

The cause of pancreatitis is unknown in as many as 30% of cases of recurrent acute pancreatitis, even after ERCP.

OBJECTIVE

To investigate the role of intraductal US (IDUS) for managing idiopathic recurrent pancreatitis (IRP).

DESIGN

Prospective study.

SETTING

Tertiary referral hospital.

PATIENTS

Thirty-one patients with suspicious IRP with negative findings on ERCP.

INTERVENTIONS

IDUS during ERCP.

MAIN OUTCOME MEASUREMENTS

IDUS findings showing any possible cause of pancreatitis.

RESULTS

IDUS revealed small bile duct stones (≤3 mm) in 5 patients (16.1%) and sludge in 3 patients (9.7%). The detection rate for a bile duct stone and sludge was significantly higher in patients with a dilated CBD than a nondilated CBD on ERCP (71.4 vs 12.5%; P < .05). Recurrent pancreatitis did not develop in 7 of 8 patients with biliary stones or sludge after an endoscopic sphincterotomy (EST). Two patients (6.5%) demonstrated a small polypoid lesion on the distal end of the pancreatic duct. One patient underwent surgery for intra-ampullary cancer, and another one underwent EST without another attack of pancreatitis. Three patients (9.7%) showed evidence of chronic pancreatitis with small pancreatic stones and/or calcifications on IDUS.

LIMITATIONS

Small number of patients. IDUS results were not compared with those of conventional EUS. There was no reference standard for chronic pancreatitis as diagnosed by IDUS.

CONCLUSIONS

IDUS identified a possible cause of idiopathic recurrent pancreatitis in 42% of patients with negative findings on ERCP. The IDUS-guided approach combined with ERCP and EST may be useful for decreasing recurring attacks of pancreatitis.

5. Imaging techniques in diagnostic approaches

Despite the considerable technological advances in imaging modalities which have occurred over the last years, EUS remains one of the most reliable and accurate technique for the study of gastroenteropancreatic neuroendocrine tumors. More specifically, EUS can detect very small lesions, assess the local extent and lymph node involvement and biopsy the lesion for cytophatological confirmation (EUS-FNA). In addition, nuclear medicine imaging has a relevant role in the evaluation of NET. However, its performance depends on series of patient-specific features (lesion size and uptake, depth and other anatomic features; metabolic activity, receptor expression, affinity and vacancy, tissue specificity) and technical features (choice of tracer, administered dose, and physical half-life; instrument sensitivity, acquisition technique, reader experience). In particular, current data show that PET/CT has greater intrinsic resolution and sensitivity than SPECT or SPECT/CT images resulting in improved tumor detection. However, the PET tracer of choice has not yet been identified. 18F-FDG has proved to be useful as indicator of tumor aggressiveness rather than detection of extent of disease, and 68Ga-DOTA-TOC has demonstrated good results in clinical trials. 11C-5HTP has performed well in limited trials, but the 20-min half life of 11C precludes widespread availability. Better information concerning biodistribution and further comparative data of these agent in larger clinical trials are warranted. Free full text available at www.tumorionline.it

Endoscopic retrograde cholangiopancreatography in the diagnosis and management of cholangiocarcinoma

Cholangiocarcinomas (CCAs) are rare malignancies that arise from the biliary epithelium. Intrahepatic CCAs usually present as mass lesions that are asymptomatic or cause nonspecific systemic symptoms such as fatigue, fever, and weight loss. Hilar and extrahepatic tumors most commonly present with jaundice, though cholangitis also can be seen. Tumor markers such as carbohydrate antigen 19-9 and carcinoembryonic antigen have been used to diagnose CCA, but these are nonspecific and may be elevated in infection, inflammation, or any obstruction. Endoscopic retrograde cholangiopancreatography (ERCP) has been used for the diagnosis and management of CCA for many years. This article summarizes the data regarding the application of ERCP in the diagnosis and management of CCA.

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.

Diagnostic approaches for cholangiocarcinoma

Cholangiocarcinomas arise from the epithelial cells of the bile ducts and are associated with poor prognosis. Despite new diagnostic approaches, the definite diagnosis of this malignancy continues to be challenging. Cholangiocarcinomas often grow longitudinally along the bile duct rather than in a radial direction. Thus, large tumor masses are frequently absent and imaging techniques, including ultrasound, CT, and MRI have only limited sensitivity. Tissue collection during endoscopic (ERCP) and/or percutaneous transhepatic (PTC) procedures are usually used to confirm a definitive diagnosis of cholangiocarcinoma. However, forceps biopsy and brush cytology provide positive results for malignancy in about only 50% of patients. Percutaneous and peroral cholangioscopy using fiber-optic techniques were therefore developed for direct visualization of the biliary tree, yielding additional information about endoscopic appearance and tumor extension, as well as a guided biopsy acquistion. Finally, endoscopic ultrasonography (EUS) complements endoscopic and percutaneous approaches and may provide a tissue diagnosis of tumors in the biliary region through fine-needle aspiration. In the future, new techniques allowing for early detection, including molecular markers, should be developed to improve the diagnostic sensitivity in this increasing tumor entity.

Novel endoscopic approaches for assessing biliary tract diseases

PURPOSE OF REVIEW

Biliary endoscopy offers both diagnostic and therapeutic value in complex clinical situations. This review addresses the latest advances over the past year in endoscopic approaches of biliary tract diseases.

RECENT FINDINGS

Specifically, we focus on the latest findings on endoscopic retrograde cholangiopancreatography for the evaluation of biliary strictures. In addition, key studies have demonstrated the enhanced role of cholangioscopy, photodynamic therapy in cholangiocarcinoma, and biliary stent technology.

SUMMARY

The following review focuses on the latest advancements in the field of biliary endoscopy. Pivotal studies were selected to highlight some of the current investigations in therapeutic endoscopic retrograde cholangiopancreatography as well as knowledge gaps for future research.

Diagnosis and management of cholangiocarcinoma

Cholangiocarcinoma (CC) is a rare yet frequently fatal tumor that causes significant morbidity and mortality due to late presentation. Radiology is the mainstay of CC diagnosis; however, advances in understanding the pathogenesis of CC, including the role of oncogenes, inflammation-mediated genomic instability, and interleukin-6/STAT-3 signaling pathways, may allow development of new diagnostic and prognostic markers and targets for CC therapy. Although surgical resection is the standard of care for resectable CC, liver transplantation has shown excellent results in selected patients. The use of chemotherapy and radiotherapy are currently limited by marginal response rates, toxicity, and biliary complications. Locally ablative therapies in the form of transcatheter arterial chemoembolization and radioembolization are under investigation. Molecular therapies (eg, epidermal growth factor receptor, ErbB-2, and vascular endothelial growth factor receptor antagonists) and immunotherapy using diabodies are also under investigation for treatment of unresectable CC.

Complications and diagnostic difficulties arising from biliary self-expanding metal stent insertion before definitive histological diagnosis

BACKGROUND

Self-expanding metal bile duct stents provide good palliation for inoperable malignant disease. However, problems may arise if metal stents are inserted before definitive histological diagnosis. The aim of this study was to evaluate the outcome of such patients.

METHODS

A retrospective case note review was conducted of patients referred to a tertiary pancreaticobiliary center between 1992 and 2004 in whom a metal bile duct stent was inserted for presumed unresectable malignant disease before definitive histological diagnosis.

RESULTS

There were 21 patients identified. Final diagnoses were: group 1, benign disease (n = 3); group 2, resectable malignancy (n = 2); group 3, unresectable malignancy (n = 12); and group 4, diagnosis remains uncertain (n = 4). During a follow-up of 22, 38 and 111 months, the patients in group 1 had one, eight and five episodes of stent occlusion. In group 2, both patients underwent pancreaticoduodenectomy for ampullary carcinoma, 2 and 6 months after presentation. In group 3, the median time to a confirmed malignant diagnosis was 2 months (range 1-27 months). In group 4, a median of two biopsies (range 1-4) were negative for malignancy, during a median follow up of 13 months (range 3-46). Overall in eight patients, the metal stents caused artifacts on computed tomography and/or were associated with tissue in-growth making the differentiation between benign and malignant disease difficult.

CONCLUSION

These cases indicate that metal bile duct stent insertion before definitive histological diagnosis can be problematic. A proportion of cases will have benign strictures and in others the confirmation of malignancy may be made more difficult.

Nonoperative imaging techniques in suspected biliary tract obstruction

Evaluation of suspected biliary tract obstruction is a common clinical problem. Clinical data such as history, physical examination, and laboratory tests can accurately identify up to 90% of patients whose jaundice is caused by extrahepatic obstruction. However, complete assessment of extrahepatic obstruction often requires the use of various imaging modalities to confirm the presence, level, and cause of obstruction, and to aid in treatment plan. In the present summary, the literature on competing technologies including endoscopic retrograde cholangiopancreatography (ERCP), percutaneous transhepatic cholangiopancreatography (PTC), endoscopic ultrasound (EUS), intraductal ultrasonography (IDUS), magnetic resonance cholangiopancreatography (MRCP), helical CT (hCT) and helical CT cholangiography (hCTC) with regards to diagnostic performance characteristics, technical success, safety, and cost-effectiveness is reviewed. Patients with obstructive jaundice secondary to choledocholithiasis or pancreaticobiliary malignancies are the primary focus of this review. Algorithms for the management of suspected obstructive jaundice are put forward based on current evidence. Published data suggest an increasing role for EUS and other noninvasive imaging techniques such as MRCP, and hCT following an initial transabdominal ultrasound in the assessment of patients with suspected biliary obstruction to select candidates for surgery or therapeutic ERCP. The management of patients with a suspected pancreaticobiliary condition ultimately is dependent on local expertise, availability, cost, and the multidisciplinary collaboration between radiologists, surgeons, and gastroenterologists.

Review article: current management of primary sclerosing cholangitis

The management of primary sclerosing cholangitis (PSC) is hindered by incomplete understanding of the pathogenesis of the disease and the lack of good prognostic models. Few large randomized controlled trials of drug therapy have been published. Best practice in the management of PSC is currently based therefore on careful interpretation of the available evidence, close observation of individual patients and clinical experience of the disease. Drug therapy is useful for alleviating symptoms. Ursodeoxycholic acid may slow progression of the disease and reduce the frequency of complications. Consensus is emerging on the issues of screening for the malignant complications of PSC and the indications for liver transplantation are becoming broader and encompassing the earliest stages of cholangiocarcinoma. In view of the rarity of the disease in the general population, large international collaborations to study PSC are necessary to provide clearer answers in areas of uncertainty, and these are now beginning to emerge.

Pancreatic neoplasms

Patients who present with signs and symptoms suggesting a pancreatic neoplasm typically undergo initial imaging with transabdominal ultrasound or CT. When a pancreatic mass or fullness is identified, it may represent an inflammatory mass, benign process, or malignancy. Endoscopic ultrasound (EUS) is performed commonly to further characterize the lesion, obtain a tissue diagnosis, and for staging. This article reviews the role of EUS for the diagnosis and staging of pancreatic tumors.

Evaluation and management of cystic pancreatic tumors: emphasis on the role of EUS FNA

Cystic lesions of the pancreas are increasingly recognized and usually represent pseudocysts or cystic pancreatic tumors (CPTs), but also include congenital cysts, acquired cysts, extrapancreatic cysts, or cystic degeneration of solid tumors. It is important to distinguish CPT lesions given their varied prognosis and therapy. Mucinous varieties of CPTs (mucinous cystic neoplasms and intraductal papillary mucinous tumors) are premalignant or malignant, and surgical resection is generally recommended in good operative candidates. In contrast, nonmucinous CPTs include serous cystadenomas with a very low malignant potential, or pseudocysts, which are always benign. As a result, nonmucinous CPTs are generally resected only when inducing symptoms or complications. Review of the clinical, imaging, laboratory, and pathology information may clarify the specific tumor type. The relatively limited accuracy of any one modality requires that we consider the combined results when making management decisions.

Endoscopic ultrasound and fine-needle aspiration of unexplained bile duct strictures

OBJECTIVES

The aim of this study was to assess the utility of endoscopic ultrasound (EUS) with fine-needle aspiration (FNA) in patients with unexplained common bile duct strictures after endoscopic retrograde cholangiopancreatography (ERCP) and intraductal tissue sampling.

METHODS

Records were reviewed for all subjects undergoing EUS for evaluation of unexplained bile duct strictures at our institution. 40 subjects had either a final histologic diagnosis (24) or no evidence of malignancy after at least 1 yr of follow-up (16).

RESULTS

The finding of a pancreatic head mass and/or an irregular bile duct wall had sensitivity for malignancy of 88%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 84%. Bile duct wall thickness >/=3 mm had a sensitivity for malignancy of 79%, specificity of 79%, positive predictive value of 73%, and negative predictive value of 80%. Sensitivity of EUS FNA for malignancy was 47% with specificity 100%, positive predictive value 100%, and negative predictive value 50%.

CONCLUSIONS

Sonographic features may be more sensitive than EUS FNA for diagnosis of unexplained bile duct strictures and include presence of a pancreatic mass, an irregular bile duct wall, or bile duct wall thickness > 3 mm. EUS FNA cytology is specific but insensitive for diagnosis. EUS improves the diagnosis of otherwise unexplained bile duct strictures.

Diagnosis and treatment of cholangiocarcinoma

Epidemiologic studies have demonstrated increasing mortality rates from intrahepatic cholangiocarcinoma during the past decades. Primary sclerosing cholangitis is the most important predisposing condition to the development of cholangiocarcinoma. Improvements in noninvasive diagnostic techniques have led to decreased use of invasive procedures. Magnetic resonance imaging (MRI) has the potential to depict parenchymal, ductal, and vascular tumor involvement. However, diagnosis can be difficult, and often ultrasonography, MRI, CT, and invasive cholangiography are complementary investigations. Genetic aberrations in brush cytology specimens should be explored further in prospective studies. Endoscopic ultrasonography, intraductal ultrasonography, and positron emission tomography are interesting techniques that are under evaluation. Radical surgery with negative histologic margins is the only curative option in cholangiocarcinoma. With more aggressive surgical approaches, including partial hepatectomy, 3-year survival rates of 35% to 50% can be achieved. Liver transplantation for unresectable cholangiocarcinoma was shown to be feasible in pilot studies of highly selected patients.

Innovative methods of biliary tract diagnosis: intraductal ultrasound and tissue acquisition

Tissue can be acquired from the bile and pancreatic duct with either brush cytology or biopsy forceps, often without the need for sphincterotomy. Although the diagnosis of malignancy with these sampling techniques is often specific, the sensitivity is limited, and a wide range of diagnostic accuracies has been reported. A combination of biopsy and brush cytology along with some newer techniques in the development stage may increase the sensitivity. Intraductal ultrasound is a newer technique offers the endoscopist the ability to image the bile and pancreatic duct wall, adjacent organs, and vascular structures with a high degree of detail. This visualization can be accomplished during the course of an ERCP or percutaneously under fluoroscopic guidance. Indications for the procedure include detection of choledocholithiasis, differentiation of benign and malignant ductal strictures, pancreaticobiliary tumor staging, and detection of various pancreatic tumors. Continued research into the design of the probes, which could improve durability and extend the depth of penetration, may promote more widespread use of this novel technology.

Selective MRCP and CT-targeted drainage of malignant hilar biliary obstruction with self-expanding metallic stents

BACKGROUND

Endoscopic management of malignant hilar biliary obstruction is controversial with respect to optimal types of stents and extent of drainage. This study evaluated outcomes of selective MRCP and CT-targeted drainage with self-expanding metallic stents.

METHODS

Consecutive patients undergoing attempted palliative ERCP for malignant hilar biliary obstruction were prospectively followed. Whenever possible, management strategy included evaluation and staging for potential resectability before ERCP, with primary placement of metallic stents at the first ERCP in nonsurgical candidates, and early conversion to a metallic stent when a tumor proved to be unresectable. MRCP and/or CT were used to plan selective guidewire access, opacification, and drainage only of the largest intercommunicating segmental ducts. Unilateral stent placement was intended in all cases except for selected patients with Bismuth II cholangiocarcinoma.

RESULTS

Thirty-five patients were included. Bismuth classification was I, 10; II, 6; III, 8; and IV, 11. Tumor origin was bile duct (17), gallbladder (5), and metastatic (13). Metallic stents were placed in 27 patients as the initial stent, and in 8 after plastic stent placement. Initial stents were placed endoscopically in 33 patients and percutaneously in 2 patients in whom lumenal tumor precluded ERCP. Stent placement was unilateral in 31 patients and bilateral in 4 patients. There were no episodes of cholangitis or other complications within 30 days after any procedures. Initial metallic stents were clinically effective in 27 (77%) of the 35 patients. Additional percutaneous drainage in 3 patients who did not respond to initial stent placement did not resolve jaundice. Median patency of first metallic stents was 8.9 months for patients with primary bile duct tumors and 5.4 months for all patients, and was not related to Bismuth classification. No further intervention was needed in 25 (71%) patients.

CONCLUSIONS

Unilateral metallic stent placement by using MRCP and/or CT to selectively target drainage provides safe and effective palliation in most patients with malignant hilar biliary obstruction.