ENDOSCOPIC OBSERVATION OF MUCOSAL SPREAD LESION OF CHOLANGIOCARCINOMA USING PERORAL CHOLANGIOSCOPY WITH NARROW BAND IMAGING

A 69‐year‐old man was admitted to Toho University Omori Medical Center complaining of icterus. Abdominal computed tomography, magnetic resonance cholangiopancreatography and endoscopic retrograde cholangiopancreatography were suspicious of cholangioma of inferior bile duct. Peroral cholangioscopy using narrow band imaging (NBI) was performed and it was possible to diagnose the mucosal spread lesions of cholangioma. Histological findings reflected the endoscopic findings. Mucosal spread lesions of cholangiocarcinoma were successfully diagnosed using the CHF‐B260 for NBI.     

EVALUATION OF NARROW BAND IMAGING FOR PERORAL CHOLANGIOPANCREATOSCOPY

Used with narrow band imaging (NBI), peroral cholangiopancreatoscopy (PCPS) was performed in eight patients with biliary and pancreatic diseases. The procedures were successfully performed in all patients without any complications after endoscopic sphincterotomy. Direct endoscopic diagnosis within both the bile and pancreatic ducts was well accomplished by the baby scope with NBI. NBI produced higher quality images and was able to show changes of the bile duct wall due to tumor growth. However, bile is seen as red on NBI, so sufficient cleaning of the bile duct is recommended. It is concluded that this procedures is considerably valuable and enables PCPS to easily detect biliary lesions.     

WHAT'S NEW IN CHOLANGIOSCOPY? IS NARROW BAND IMAGING CHOLANGIOSCOPY THE NEXT GENERATION?

Narrow band imaging (NBI) makes it possible to emphasize the imaging of certain features such as mucosal structures and mucosal microvessels in gastrointestinal tract diseases. Recently, video peroral cholangioscopy (POCS) has been developed as diagnostic endoscopy for better observation of bile duct lesions, but there is no report on POCS using NBI. Herein is described the efficacy of POCS using NBI for the observation of both fine mucosal structures and tumor vessels, resulting in correct target biopsy in patients with biliary tract diseases.     

ENDOSCOPIC DIAGNOSIS OF INTRADUCTAL PAPILLARY MUCINOUS NEOPLASM USING PERORAL PANCREATOSCOPY WITH NARROW BAND IMAGING

A 77‐year‐old man was diagnosed with a pancreas cyst at another hospital. Abdominal ultrasonography revealed a cyst in the head of the pancreas and a small protrusion. These findings suggested intraductal papillary mucinous neoplasm. Cytologic finding of the pancreatic juice revealed a Class III lesion, and intraductal ultrasonography and peroral pancreatoscopy (PPS) were performed. An abnormal course of main pancreatic duct (MPD) prevented the insertion of an ultrasonography probe into the MPD, and PPS was performed. The mucosal surface of the MPD near the papillary area was normal, and narrow band imaging (NBI) clearly showed the vascular structure. When the PPS was inserted more deeply, many small protrusions were observed and NBI delineated the protrusions more clearly. Papillary protrusions were observed in the cyst, but NBI did not reveal any tumor vessels. These findings led to a diagnosis of benign intraductal papillary mucinous neoplasm lesion. Since then, follow‐up examinations have been made. Changes in the cyst and protrusion have not been observed.     

PERORAL CHOLANGIOSCOPY: AN IMPROVED PROCEDURE

Cholangioscopy provides direct visual assessment of the bile ducts, tissue sampling, and therapeutic interventions. Delineation of intraductal lesions equivocal with direct cholangiography, differentiation between malignant and benign biliary strictures, and assessment of longitudinal extent of cholangiocarcinoma are major indicators for diagnostic cholangioscopy. Peroral cholangioscopy is readily performed at an initial endoscopic retrograde cholangiopancreatography. Owing to substantial refinement in terms of image quality and technical feasibility achieved with the development of a new video cholangioscope, peroral cholangioscopy has become a powerful tool. However, compared with percutaneous cholangioscopy, there remain several disadvantages in peroral cholangioscopy: less favorable maneuverability, small instrumental channel, and limited therapeutic instrumentations. With further advances in endoscopic functions and increasing availability of suitable instruments, peroral cholangioscopy, because of its less invasiveness, will become mandatory for diagnostic and therapeutic biliary endoscopy.     

DIAGNOSTIC UTILITY OF PERORAL CHOLANGIOSCOPY AND TRANSPAPILLARY INTRADUCTAL ULTRASONOGRAPHY FOR BILE DUCT CARCINOMA

Recently, new diagnostic procedures such as video peroral cholangioscopy (POCS) and transpapillary intraductal ultrasonography (IDUS) have been available for diagnosis of biliary diseases. These new modalities are especially useful for diagnosis of minute bile duct lesions on cholangiogram and correct diagnosis of lateral extension of bile duct carcinoma. In this paper, showing some effective cases of POCS and IDUS, we present our diagnostic approach for bile duct carcinoma and discuss the future prospects of POCS and IDUS.     

INFLAMMATORY PROTRUDING LESION IN THE INTRAHEPATIC BILIARY DUCT DIAGNOSED ON NARROW BAND IMAGING–VIDEOCHOLANGIOSCOPY

A 66‐year‐old woman who had a repeated history of cholangitis since undergoing choledocho‐jejunostomy for post‐cholecystectomy common bile duct stricture, was referred to Kyoto University Hospital for further examination of the stricture of left intrahepatic biliary duct (IHBD). Endoscopic retrograde cholangiography (ERC) showed obstruction of the left IHBD with slightly protruding lesion. Peroral cholangioscopy (POCS) with narrow band imaging (NBI) demonstrated that a protruding lesion with papillary surface had neither tumor vessels on the surface of the tumor nor microvessel in each papillary projection. Biopsy presented only inflammation. Pathological analysis of the resected left lobe also showed only inflammatory change. NBI‐videocholangioscopy appears to be useful for diagnosing biliary disease by evaluating the tumor vessels including microvessel in papillary projection.     

PERORAL PANCREATOSCOPY: CURRENT STATUS AND FUTURE EXPECTATIONS USING NARROW BAND IMAGING

Peroral pancreatoscopy (POPS) under duodenoscopic assistance provide direct visual assessment of the pancreatic duct, tissue sampling, and therapeutic interventions. Sometimes, pancreatoscopy can confirm accurate diagnosis, such as differential diagnosis of filling defects between intraductal tumors and stones. However, it is often difficult to differentiate malignant from benign strictures solely on pancreatoscopy. It is currently considered that intraductal papillary mucinous neoplasm (IPMN) is the most suitable indication of POPS. POPS has several problems: image resolution, fragility and maneuverability. Concerning image resolution, the quality has been improved with the development of a video pancreatoscope. Moreover, the recently developed endoscopic optical technology of narrow band imaging (NBI) is now available to video pancreatoscopy. This will allow direct visual assessment. Although currently POPS has several problems, further improvement will assist POPS to become a useful modality in combination with NBI.     

NEW APPLICATION OF NARROW BAND IMAGING FOR CHOLANGIOPANCREATOSCOPY

The usefulness of narrow band imaging (NBI), which is based on the principle that the depth of light penetration depends on its wavelength, has been accepted for evaluating malignant or benign lesions in the pharynx, the upper, and lower gastrointestine. The purpose of the present paper was to investigate NBI for diagnosing biliopancreatic disease. Using NBI it has become easy to detect the surface microstructure of biliary mucosa and subjacent vascular network of the bile duct, and inflammatory scarring stenosis is visualized as a whitish scar and multiple inflammatory red spots. However, bile duct cancer was detected as a stenosis with abnormal subjacent vessels and irregular surface. Concerning pancreatic duct, NBI has clearly shown vascular network and spreading of branch‐type intraductal papillary mucinous neoplasm to the main pancreatic duct. In contrast, bile juice has been detected as red fluid and bleeding as black red. Therefore, it is important to flush the biliary system before observing with NBI.     

ROLE OF PERORAL CHOLANGIOSCOPY IN THE PREOPERATIVE DIAGNOSIS OF MALIGNANT MIDDLE and LOWER BILE DUCT CANCERS: A PRELIMINARY STUDY USING 10 FR PLASTIC STENT

To date, peroral cholangioscopy (POCS) with working channel for biopsy is a less than an essential means for endoscopic diagnosis of bile duct lesions. One of these reasons is that the durability of the baby scope is much improved, too delicate for use on tough lesions. Furthermore, in operable cases, it has a major disadvantage in that we cannot observe the proximal site of stricture. In this study, we introduced new methods to observe and perform the biopsy at proximal site of stricture using 10Fr plastic stent. After this method, we performed observation of proximal site of stricture without dilation and could diagnose precise incision line preoperatively in all cases. Importantly, all procedures were done within one week from the first endoscopic retrograde cholangiopancreatography (ERCP). Although further investigation and development of baby scopes are necessary, POCS using 10Fr plastic stent will make it possible to evaluate the hepatic site of spreading cancer in patients with middle or lower bile duct cancer.     

LIMITATIONS OF PERORAL CHOLANGIOSCOPY IN THE DIAGNOSIS OF BILIARY TUMORS

In patients with carcinoma of the bile duct, a primary tumor with tumor spread along the bile duct is frequently shown as a stricture of the bile duct with ductal irregularity and rigidity on ERCP. In patients in whom histological diagnosis is necessary, larger caliber peroral cholangioscopes with a larger working channel should be chosen because they have the advantage of simultaneous biopsy diagnosis. However, peroral cholangioscopy (POCS) has limitations to inspect mucosal tumor spread along the upstream ducts due to the tight stricture, to obtain sufficient biopsy material for confirming the diagnosis, and to identify submucosal tumor spread. With further improvement of techniques, the combined use of POCS with biopsy under direct vision and intraductal ultrasonography (IDUS) is expected to be the best way in the diagnosis of biliary tumors.     

THE ROLE OF PERORAL CHOLANGIOSCOPY FOR BILE DUCT LESIONS

We reviewed the current status of peroral cholangioscopy under duodenoscopic assistance, which allows direct visualization of the bile duct. Direct visual assessment may be a useful adjunct to endoscopic retrograde cholangiopancreatography (ERCP) for distinguishing malignant from benign bile duct lesions. Several clinical studies suggest the efficacy of peroral cholangioscopy for various bile duct lesions. However, solely cholangioscopic examination may be insufficient to confirm accurate differential diagnosis between benign and malignant strictures or tumor extension of bile duct carcinoma. Directed tissue acquisition in biliary strictures by using peroral cholangioscopy is another application that has not been properly studied because of the limited maneuverability of the long babyscope. Further improvement of suitable instruments and cholangioscopes are needed.     

A CASE OF CHOLESTEROSIS OF THE COMMON BILE DUCT DIAGNOSED BY PERORAL CHOLANGIOSCOPY

We experienced a case of cholesterosis of the common bile duct in which peroral cholangioscopy (POCS) was very useful for making a diagnosis. The patient was a 66‐year‐old man. He was admitted for examination of an asymptomatic mass in the pancreas. The mass was diagnosed as a serous cystic tumor of the pancreas. While examining the tumor, endoscopic retrograde cholangiopancreatography (ERCP) incidentally revealed a 7 mm irregular filling defect in the distal common bile duct. EST was then performed, followed by POCS, which revealed a clump of yellowish‐white Ip or Isp polyps in the distal bile duct. Histological examination of biopsy specimens taken under direct vision gave a diagnosis of cholesterol polyps containing foamy cells. POCS was useful for allowing direct observation of the characteristic color of cholesterol polyps, and for obtaining biopsy specimens under direct vision.     

TWO CASES OF MUCIN‐PRODUCING CHOLANGIOCARCINOMA DIAGNOSED BY PERORAL CHOLANGIOSCOPY

Mucin‐producing cholangiocarcinoma, which excretes excessive amounts of mucin into the biliary tract and causes obstructive jaundice and cholangitis due to the mucin retention, is rare. In this paper, we report two cases of this disease, which were demonstrated by peroral cholangioscopy (POCS). The radiologic features of these tumors show the diffuse dilatation of the bile ducts demonstrated by computed tomography (CT) and ultrasonography (US), the amorphous filling defects in the dilated bile ducts revealed by cholangiography. Their endoscopic features are mucin flowing out from the papilla of Vater during endoscopic retrograde cholangiography (ERC), and the papillary tumor with contiguous superficial spread in the bile ducts observed by cholangioscopy, although removal of mucin in the biliary tract is sometimes necessary before cholangioscopy in order to examine the lesion sufficiently. According to the previous reports, prognosis after curative resection of these tumors is better than that of ordinary type of cholangiocarcinoma. Therefore, it is important to examine the tumor extension in the bile ducts by cholangioscopy, although a selection of route inserting cholangioscope is controversial.     

PERORAL CHOLANGIOSCOPY USING A NEW THINNER VIDEOSCOPE (CHF‐B260)

The CHF‐B260 videoscope has a 3.4 mm outer diameter, 1.2 mm forceps channel, and two‐way angulations function (70° up and 70° down). Peroral cholangioscopy (POCS) was performed using the CHF‐B260 in 13 patients who were admitted to our hospital between October 2002 and June 2004. The CHF‐B260 was successfully inserted into the bile duct in all cases. Clear images were obtained in 11 patients. Endoscopic images for two cases of malignant stricture due to metastasis of colon cancer and gallbladder cancer were not clear because of bleeding from the tumors. POCS was performed safely in all patients without any complications. POCS with the CHF‐B260 was very useful for the diagnosis of biliary disorders. If the outer diameter and biopsy channel of CHF‐B260 are improved, POCS will become even more effective for the diagnosis of biliary disorder.     

PIT PATTERN DIAGNOSIS FOR COLORECTAL NEOPLASIA USING NARROW BAND IMAGING MAGNIFICATION

Narrow band imaging (NBI) is a newly developed technology that uses optical filters for RGB sequential illumination and narrows the bandwidth of spectral transmittance. NBI enables the observation of the fine capillaries in the superficial mucosa of the gastrointestinal tract. In this report, the authors assessed the clinical usefulness of NBI magnification in pit pattern diagnosis for colorectal neoplasia. A total of 90 colorectal lesions including nine cases of hyperplasia, 60 of tubular adenoma and 21 of early carcinoma were analyzed. Histologic diagnosis was undertaken according to World Health Organization classifications. Magnified observation of the lesions was performed using NBI without chromoendoscopy, and pit pattern diagnosis was then recorded. After endoscopic or surgical resection of the lesion, the authors performed stereoscopic examination to confirm the pit pattern. From these data, the authors estimated the ability to diagnose pit patterns using NBI magnification without chromoendoscopy. The correspondence rate of pit pattern diagnosis between NBI magnification without chromoendoscopy and stereoscopic findings was 100% (9/9) for type II, 100% (56/56) for type IIIl , 100% (3/3) for type IV, 80% (12/15) for type Vi , and 57% (4/7) for type Vn . NBI magnification without chromoendoscopy demonstrated good results for pit pattern diagnosis of colorectal neoplasia, especially for lesions with regular pit pattern.     

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.     

ENDOSCOPIC APPROACH TO THE PANCREATOBILIARY TRACT USING NARROW BAND IMAGING

Narrow band imaging (NBI), based on modifying spectral features by narrowing the bandwidth of spectral transmittance, makes it possible to clearly observe the microvascular architecture or fine superficial structure of the gastrointestinal tract. Using a thinner video endoscope recently developed and not equipped with magnifying mode, the authors have evaluated the clinical usage of NBI for the pancreatobiliary region. Between June and July 2006, peroral pancreatoscopy or cholangioscopy was performed for 10 patients with pancreatobiliary diseases. The scope with an outer diameter of 2.9 mm was used. Non‐magnifying NBI observation was compared with standard observation. NBI observation visualized the small vessels and superficial architecture, which were difficult to depict on standard observation. Furthermore, NBI clearly delineated the margin of the small‐protruding lesion. Consequently, NBI pancreatoscopy was more useful for diagnosing tumor spread in the main pancreatic duct of the intraductal mucinous neoplasm.     

MAGNIFYING ENDOSCOPY WITH NARROW BAND IMAGING FOR EARLY DIFFERENTIATED GASTRIC ADENOCARCINOMA

We have been using magnifying endoscopy with narrow band imaging (NBI) to study early differentiated gastric adenocarcinomas and to assess the relationship between microvessel pattern, pit pattern and histological pattern. The magnified view of the cancerous area showed three types of pattern: (i) a mesh pattern, consisting of mesh‐like connected microvessels; (ii) a loop pattern, consisting of loop‐like microvessels that were not connected and had tubule‐like or villus‐like mucosal structures along them; and (iii) an interrupted pattern, consisting of interrupted thick or thin vessels without mucosal structures. The mesh type of microvascular pattern showed a round pit pattern in 88.9% of cases (32/36) and the loop type of microvascular pattern showed a non‐round pit pattern in 100% of cases. Among lesions that showed a mesh pattern or a loop pattern, 94.9% (56/59) were mucosal cancer and 5.1% (3/59) were submucosal cancer. However, 92.3% (12/13) of lesions that showed an interrupted pattern were submucosal differentiated adenocarcinoma and 7.7% (1/13) were mucosal differentiated adenocarcinoma. The present findings provide basic data on the characteristics of mucosal differentiated gastric adenocarcinoma revealed by magnifying endoscopy with NBI, as well as invasive changes such as submucosal invasion.     

NARROW BAND IMAGING IN THE DETECTION OF COLORECTAL POLYP: KOREAN EXPERIENCE

Background: Although white light (WL) colonoscopy is a gold standard to detect colorectal polyps, substantial polyps are missed. Narrow band imaging (NBI) is a new technology that enables a more detailed visualization of the mucosal surface. The aim of the present study was to determine whether NBI can improve the detection of colorectal polyps. Methods: We prospectively enrolled 188 (M : F = 99:89, 21–80 years) subjects undergoing colonoscopy as a screening procedure in nine referral centers. After a careful WL examination of the whole colorectum, rectosigmoid colon (0–30 cm from the anal verge) was reobserved by NBI. Size, macroscopic morphology, and the histology of all the polyps detected during WL and NBI examination were analyzed. Results: WL examination detected 162 polyps in 188 subjects, of which 106 lesions were neoplastic, while NBI of rectosigmoid colon detected an additional 61 polyps of which eight lesions were neoplastic. Only 10 (6.2%) of 162 polyps discovered during WL examination were flat polyps compared to 10 (16.4%) of 61 newly detected polyps during NBI being flat type (P = 0.002). The mean polyp size detected by NBI was smaller than that found by WL colonoscopy (2.8 ± 1.0 mm vs 6.5 ± 4.5 mm, P < 0.001). Conclusion: Many additional colorectal polyps, especially flat type, could be detected by NBI examination for normal‐looking rectosigmoid mucosa. The role of NBI in colorectal neoplasm screening needs to be further investigated in future studies.