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

Endoscopic findings of gallbladder lesions evaluated with image-enhanced endoscopy: A preliminary study using resected gallbladders

The diagnosis of gallbladder (GB) lesions relies on imaging findings. Transpapillary cholangioscopy can potentially be used to diagnose GB lesions; however, the images obtained remain unclear. This study aimed to characterize the endoscopic findings of GB lesions. We examined the endoscopic features of GB lesions in 50 consecutive patients who underwent cholecystectomy. GB specimens were obtained immediately following cholecystectomy, opened on the side opposite the liver bed, and flushed with saline solution. Each lesion was assessed using a high-resolution endoscope equipped with white light and narrow-band imaging magnification. For elevated lesions, both the surface structure (classified as regular, irregular, or absent) and vascular structure (dilation, meandering, caliber change, non-uniformity, and loose vessel areas) were assessed. Twelve of the 50 patients had elevated lesions, including cholesterol polyp (n = 4), hyperplastic polyp (n = 1), xanthogranulomatous cholecystitis (n = 1), and GB carcinoma (n = 6). Advanced GB carcinoma, as opposed to T1 GB carcinoma, demonstrated a papillary surface with destructive areas and neovascularization on narrow-band imaging magnification. Endoscopic images of each GB lesion were characterized, and the differences between GB carcinomas and benign lesions were identified. This preliminary classification may contribute to innovative imaging diagnosis and targeted biopsy for diagnosing GB lesions under direct vision.

Can image-enhanced cholangioscopy distinguish benign from malignant lesions in the biliary duct?

A new video peroral cholangioscopy (POCS) has been developed with high-quality digital imaging, and its clinical use has been reported. Additionally, direct peroral cholangioscopy (D-POCS) using an ultraslim endoscope has been proposed recently. To improve the diagnostic yield of POCS or D-POCS, image-enhanced endoscopy has been used in combination. Chromoendoscopy with methylene blue staining (ME), autofluorescence imaging (AFI), and narrow-band imaging (NBI) has been evaluated in biliary tract diseases. Observation of the mucosal structure and vessels is reportedly important for distinguishing non-neoplasms from neoplasms. Therefore, NBI is the most promising tool among image-enhanced endoscopies as it can enhance visualization of the mucosal structure and vessels simultaneously. There are currently few reports that have evaluated the utility of POCS or D-POCS based on pathological findings. Thus, endoscopic findings of the bile duct mucosa have not yet been fully established. At present, POCS-guided biopsy should be carried out.

Diagnostic value of image-enhanced video cholangiopancreatoscopy

We summarized past and present results concerning the observation capability of cholangiopancratoscopy using chromoendoscopy, autofluorescence imaging (AFI), and narrow-band imaging (NBI). New generation peroral and percutaneous transhepatic video cholangiopancreatoscopes provide superior quality images. Pilot studies suggest that chromoendocholangioscopy using methylene blue or cholangioscopy using AFI can distinguish benign from malignant bile duct lesions. On the other hand, the NBI system enhances the imaging of certain features such as mucosal structures and microvessels in pancreatobiliary lesions. In patients with main-duct-type intraductal papillary mucinous neoplasm, peroral pancreatoscopy can be used to determine extent of tumor involvement. Although many technical hurdles still need to be overcome, image-enhanced cholangiopancratoscopy appears to be a promising modality to improve diagnostic accuracy of pancreatobiliary diseases, particularly in distinguishing benign from malignant lesions.

Effectiveness of peroral cholangioscopy and narrow band imaging for endoscopically diagnosing the bile duct cancer

CHF-B260 has thinner diameters, and the quality of the endoscopic images has improved. Recently, narrow band imaging (NBI) system has been developed for high-contrast observation of mucosal structures and vascular patterns. It is available to diagnose for the bile duct cancer endoscopically and it is useful for desciding of surgical margin before operation. As for its applicability to investigating the progression of superficially infiltrated bile duct cancer, additional cases must be examined in the future.

Evaluation of peroral videocholangioscopy using narrow-band imaging for diagnosis of intraductal papillary neoplasm of the bile duct

BACKGROUND

It is very important for intraductal papillary neoplasm of the bile duct (IPNB) to determine the extension of the neoplasms because of substantial differences in the approach to treatment strategy. Peroral videocholangioscopy (PVCS) has been developed as a new diagnostic tool for high resolution imaging of biliary disorders. Recently, narrow-band imaging (NBI) has made it possible to emphasize the imaging of certain features, such as mucosal structures and capillary vessels. The aim of this study is to evaluate the clinical usefulness of PVCS using NBI for the diagnosis of IPNB.

PATIENTS AND METHODS

Four patients (3 men and 1 woman) were eligible for this study as they were scheduled for PVCS for evaluation of IPNB between August 2005 and September 2008 at Tokyo Medical University Hospital. We evaluated endoscopic imaging of white light imaging (WLI) and NBI for IPNB lesions, and ability of removing mucin in the bile duct by PVCS. The quality of the visualization was evaluated. : (i) poor, (ii) fair, and (iii) excellent, compared to WLI and the feasibility of irrigation: (i) poor, (ii) fair, and (iii) excellent, compared to those in patients with non-mucin-producing biliary tract diseases.

RESULTS

After sufficient removal of mucin by balloon catheter, conventional cholangioscopy could detect the papillary lesion, and revealed the range of tumor spread in all cases. Interestingly, another papillary lesion far from the main tumor was detected only by PVCS. In the ability to detect the fine mucosal structure, NBI was predisposed to be better than conventional imaging while only one case was "poor" by NBI observation because we could not eliminate the influence of bile.

CONCLUSION

Our results presented here suggest that the depiction ability of the margin of lesions by NBI observation is superior to conventional observation if abundant mucin can be removed sufficiently. Although further cases should be accumulated, choledochoscopy using NBI may be helpful for the observation of fine mucosal structures, resulting in diagnosis of tumor spread in patients with IPNB.

Diagnostic videocholangioscopy using narrow-band imaging and recanalization by rendezvous technique for difficult benign biliary stricture

A 51-year-old man was hospitalized because of close examination for liver dysfunction. drip infusion cholangiography-computed tomography (DIC-CT) revealed a stricture located at the middle bile duct but normal biliary scintigraphy. Endoscopic retrograde cholangiopancreatography (ERCP) showed obstruction of bile duct. Although we tried to pass the stricture using several kinds of guidewire under direct vision of peroral cholangioscopy, recanalization could not be achieved. Then percutaneous transhepatic biliary drainage (PTBD) was conducted. Cholangioscopy using narrow band imaging showed no tumor vessel or irregular mucosa. The biopsy specimens obtained from both distal and proximal sides of stricture showed no malignancy. Eventually, a rendezvous technique was tried using guidewire under percutaneous transhepatic cholangioscopy (PTCS) direct vision. Fortunately, since a guidewire could advance into a tiny hole at the center of a scar and an endoscopic nasobiliary drainage (ENBD) tube could be placed across the biliary stricture. One week after placement of ENBD tube, a 10 Fr plastic stent was inserted and the PTBD tube was removed without procedure-related complication. Eight months later, the stent was removed and the chief complaint disappeared without liver dysfunction.