Pancreatoscopy for the next generation: development of the peroral electronic pancreatoscope system

Peroral Pancreatoscopy with Videoscopy and Narrow-Band Imaging in Intraductal Papillary Mucinous Neoplasms with Dilatation of the Main Pancreatic Duct

Background/Aims

Endoscopic evaluation of intraductal papillary mucinous neoplasms (IPMNs) is useful in determining whether the lesions are benign or malignant. This study aimed to examine the usefulness of peroral pancreatoscopy (POPS) in determining the prognosis of IPMNs.

Methods

POPS with videoscopy was performed using the mother–baby scope technique. After surgery, computed tomography/magnetic resonance cholangiopancreatography or ultrasonography and blood tests were performed every 6 months during the follow-up.

Results

A total of 39 patients with main pancreatic duct (MPD)–type IPMNs underwent POPS using a videoscope, and the protrusions in the MPD were observed in 36 patients. The sensitivity and specificity of cytology/biopsy performed at the time of POPS were 85% and 87.5%, respectively. Of 19 patients who underwent surgery, 18 (95%) patients had negative surgical margins and 1 (5%) patient had a positive margin.

Conclusions

In IPMNs with dilatation of the MPD, POPS is considered effective if the lesions can be directly observed. The diagnosis of benign and malignant lesions is possible depending on the degree of lesion elevation. However, in some cases, slightly elevated lesions may increase in size during the follow-up or multiple lesions may be simultaneously present; therefore, careful follow-up is necessary.

Current role of endoscopic pancreatoscopy

PURPOSE OF REVIEW

To provide an overview of the field of pancreatoscopy and to summarize the data informing its clinical utility.

RECENT FINDINGS

Regarding the technological advance of pancreatoscopy, recent studies are the first to report the use of digital, single-operator pancreatoscopy (SpyGlass DS; Boston Scientific, Natick, MA). New data on the use of preoperative pancreatoscopy offer promising results for the potential to optimize treatment of intraductal papillary mucinous neoplasms and to differentiate between benign and malignant pancreatic strictures. Finally, there has been accumulating evidence for the use of pancreatoscopy-guided lithotripsy for the management of painful chronic calcific pancreatitis.

SUMMARY

Endoscopic pancreatoscopy offers the advantage of direct visualization of the pancreatic duct, allowing for optimal macroscopic assessment, targeted tissue acquisition and guided therapies such as lithotripsy of pancreatic duct stones. The data informing some aspects remain limited, but the accumulating literature forms our understanding of the current and future role of pancreatoscopy in the management of pancreatic disease.

Endoscopic diagnosis of intraductal papillary-mucinous neoplasm of the pancreas by means of peroral pancreatoscopy using a small-diameter videoscope and narrow-band imaging

BACKGROUND

Intraductal papillary-mucinous neoplasm (IPMN) is an intraductal tumor in which the mucin-producing epithelium shows proliferated papillary and a wide variety of pathological changes ranging from hyperplasia to adenocarcinoma. Therefore, it is important to determine whether an IPMN is benign or malignant. In the present study of patients with IPMN, the protrusion was observed by a peroral pancreatoscopy (PPS) using a small-diameter videoscope and narrow-band imaging (NBI). We carried out the differential diagnosis of benign lesion to malignant lesion.

METHODS

Between April 2003 and May 2009, PPS using a small-diameter videoscope by means of NBI was carried out on 21 hospitalized patients with IPMN (10 cases of adenocarcinoma, 11 cases of adenoma or hyperplasia; 14 males and seven females, with a mean age of 69.4 years).

RESULTS

Fifteen focal lesions of the 16 cases in the head of the pancreas (93.7%) and four focal lesions of the five cases in the pancreatic body (80%) were observable, whereas two lesions (adenocarcinoma in the pancreatic body, and adenoma in the uncus of pancreas) were not observable. Endoscopically, seven cases were classified as villous type and two cases as vegetative type, and nine cases were diagnosed as adenocarcinoma. Ten cases with sessile type or semipedunculated type were diagnosed as adenoma or hyperplasia. Vascular patterns and protrusions were detected more clearly in the NBI images than under white light observation.

CONCLUSIONS

When combined with a videoscope and NBI, pancreatoscopy provided a clear image and was useful for evaluating whether the IPMN was benign or malignant.

Peroral pancreatoscopy in the diagnosis and management of intraductal papillary mucinous neoplasia and indeterminate pancreatic duct pathology

Peroral pancreatoscopy (POP) is an exciting modality for the evaluation of pancreatic diseases. It has proved efficacy in the evaluation of suspected intraductal papillary mucinous neoplasia and allows for a determination of the presence and extent of pancreatic duct involvement. When other imaging modalities are inconclusive, POP seems a useful adjunct in the evaluation of indeterminate pancreatic duct strictures and permits tissue sampling under direct vision. Despite recent advances, refinements in endoscope caliber, tip deflection, and optics are still required for more routine application in pancreatic diseases.

Application of per oral cholangiopancreatoscopy in pancreatobiliary diseases

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

Intraductal biliary and pancreatic endoscopy: An expanding scope of possibility

Intraductal endoscopy describes the use of an endoscope to directly visualize the biliary and pancreatic ducts. For many years, technological challenges have made performing these procedures difficult. The “mother-baby” system and other various miniscopes have been developed, but routine use has been hampered due to complex setup, scope fragility and the time consuming, technically demanding nature of the procedure. Recently, the SpyGlass peroral cholangiopancreatoscopy system has shown early success at providing diagnostic information and therapeutic options. The clinical utility of intraductal endoscopy is broad. It allows better differentiation between benign and malignant processes by allowing direct visualization and targeted sampling of tissue. Therapeutic interventions, such as electrohydraulic lithotripsy (EHL), laser lithotripsy, photodynamic therapy, and argon plasma coagulation (APC), may also be performed as part of intraductal endoscopy. Intraductal endoscopy significantly increases the diagnostic and therapeutic yield of standard endoscopic retrograde cholangiography (ERCP), and as technology progresses, it is likely that its utilization will only increase. In this review of intraductal endoscopy, we describe in detail the various endoscopic platforms and their diagnostic and clinical applications.

Pancreatoscopy: present and future role

Current imaging modalities do not allow for direct access to the pancreatic duct. Because of this limitation, diagnosis and assessment of pancreatic diseases require radiographic imaging and cytologic analysis. Although many of these techniques have excellent specificity for the detection of pancreatic cancer, they offer no therapeutic capabilities and are relatively poor in early detection of cancer and in differentiating chronic pancreatitis from malignancy, particularly when the conditions coexist. Currently available cholangioscopes are too large to access the pancreatic duct without sphincterotomy or balloon dilation, increasing the risk of instrumentation trauma to the pancreas. Novel, dedicated pancreatoscopes have recently been developed and are under investigation in clinical trials. Preliminary evidence suggests that these new technologies allow for direct visualization of the pancreatic ducts, with the potential for forceps biopsy in suspected malignancy and endotherapy for pancreatic calculi. Future and ongoing clinical trials will better define the utility and roles of these new endoscopy tools.

Initial experience with a new peroral electronic pancreatoscope with an accessory channel

BACKGROUND

A peroral electronic pancreatoscope was previously developed to improve visualization of the pancreatic duct, but this instrument had no accessory channel.

METHODS

A new peroral electronic pancreatoscope (2.6-mm external diameter) with an accessory channel (0.5 mm) was developed. Peroral pancreatoscopy or cholangioscopy was performed with this new instrument in 11 patients with various pancreatobiliary diseases. The clinical utility of the new peroral electronic pancreatoscope was assessed, and visualization with this new instrument was compared with that of the prototype.

RESULTS

The resolution of the two instrument systems was nearly equal, with that provided by the new peroral electronic pancreatoscope being slightly better. The new peroral electronic pancreatoscope was inserted successfully into the pancreatic or bile duct in 9 of the 11 patients (82%). Observation of a predetermined target and juice collection with direct visualization was successful in 8 of the 9 patients (89%).

CONCLUSIONS

The new peroral electronic pancreatoscope with an accessory channel was useful for clinical diagnosis of various pancreatobiliary diseases. Visualization is excellent. Pancreatic juice and other samples can be collected under direct visualization.

Direct cholangioscopy and pancreatoscopy

Direct cholangiopancreatoscopy has played a minor role in the diagnosis and treatment of pancreaticobiliary disorders, initially because of instrument fragility and suboptimal imaging, and later because of improvements in noninvasive and semi-invasive imaging techniques. Digital scopes provide superior images and hold the promise of increased application and improved durability.

Imaging for the diagnosis and staging of periampullary carcinomas

Multiple imaging modalities are available for investigating patients with a suspected periampullary neoplasm. The relative utility of each imaging modality is discussed regarding its role in diagnosis and staging. A general imaging approach to patients with a distal biliary obstruction also is presented.

Duodenoscope assisted cholangiopancreatoscopy: a review of clinical applications

Duodenoscope assisted cholangiopancreatoscopy allows direct visualization of the pancreatic duct and bile duct. There are several circumstances where direct ductal visualization might be helpful in clarifying a diagnosis or providing targeted treatment. Duodenoscope assisted cholangiopancreatoscopy is currently employed for a variety of indications including: indeterminate ductal strictures and filling defects, marginal chronic pancreatitis, treatment of large intraductal stones, localization of intraductal papillary mucinous tumors, and localization and treatment of hemobilia. There have however been no randomized controlled trials evaluating the diagnostic or therapeutic functions of duodenoscope assisted cholangiopancreatoscopy. This article reviews recent descriptive studies that attempt to clarify the clinical role of this technology.

A case of pseudotumorous pancreatitis that presented unique pancreatoscopic findings with the peroral electronic pancreatoscope

A 49-year-old man was admitted to Hospital of Kyoto Prefectural University of Medicine complaining of epigastralgia and jaundice. There was a tumor (approximately 30 mm) in the pancreatic head on ultrasound, computed tomography and magnetic resonance imaging. Endoscopic retrograde cholangiopancreatography revealed a stenosis of the main pancreatic duct in the head of the pancreas. Pancreatoscopy with the peroral electronic pancreatoscope (PEPS) was performed to differentiate between pseudotumorous pancreatitis (PTP) and pancreatic carcinoma. The PEPS showed non-erosive erythematous mucosa around the stenosis and this unique finding was different from that of pancreatic carcinoma. Pylorus-preserving pancreatoduodenectomy was performed under the possible diagnosis of carcinoma. As a result, the diagnosis of PTP was confirmed histopathologically. At present, the diagnosis of PTP is difficult because of similar findings with carcinoma in various imaging procedures. However, we consider that detailed observation and accurate morphologic assessment of the main pancreatic duct with the PEPS has the possibility of differentiating PTP from pancreatic carcinoma.

Electronic pancreatoscopy for the diagnosis of pancreatic diseases

OBJECTIVES

Diagnostic pancreatoscopy was performed in 56 patients using the newly developed peroral electronic pancreatoscope (PEPS). The diagnostic value of the PEPS for pancreatic diseases was evaluated.

METHODS

The PEPS (external diameter = 2.1 mm, bidirectional tip deflection) was developed with a minute 50,000-pixel interline charge-coupled device. Pancreatoscopy was performed by means of an endoscopic retrograde approach without sphincterotomy. The cases examined were normal (three), chronic pancreatitis (32), pancreatic cancer (eight), and intraductal papillary mucinous tumors (13).

RESULTS

Of the 56 cases, 42 (75%) were adequately seen. In normal cases, fine capillary vessels were clearly visualized on the smooth whitish-pink mucosa. Findings in chronic pancreatitis included protein plugs, calcified stones, rough whitish mucosa, scar formation, edema, erythema, and indistinct capillary appearance. All the stenoses of chronic pancreatitis could be differentiated from those of pancreatic cancer with the PEPS. In the pancreatic cancer cases, all patients had stenoses or duct cutoffs; most cases had friable mucosa with erythema and erosive changes, and a single patient had a compressed pancreatic duct wall covered with normal epithelium. In the cases of intraductal papillary mucinous tumors, papillary tumors were visualized with extreme clarity. In the case of adenocarcinoma, the PEPS revealed oval-shaped tumors with spotty redness or villous tumors with dilation of capillary vessels. Moderate acute pancreatitis was recognized after pancreatoscopy in one of the 56 cases (1.8%).

CONCLUSIONS

Electronic pancreatoscopy with the PEPS is feasible in most patients and technically safe, and improves diagnostic yield over conventional pancreatoscopy.