This is the prospective observational study to explore whether the SpyGlass DS II system could be used to screen early-stage neoplastic bile duct lesions in selected patients.

It is difficult to diagnose neoplastic bile duct lesions (including cholangiocarcinomas) via direct endoscopic evaluation of the bile duct. Most evaluations of biliary lesions have used indirect imaging modalities such as CT, MRI, or ERCP. However, CT and MRI do not yield tissue diagnoses, unlike ERCP, although the diagnostic accuracy for the latter remains unsatisfactory. Recently, remarkable advances in cholangioscopic systems have been made. Of the currently available cholangioscopic systems, the SpyGlass (Boston Scientific Co, Natick, Mass, USA) is a disposable cholangioscope permitting 4-way deflected steering by a single operator. We aimed to evaluate the efficacy of single-operator cholangioscopy (SpyGlass DS II system) to screen for neoplastic bile duct lesions in patients with bile duct stones, which is one of the risk factor of cholangiocarcinoma.

Inclusion Criteria:

1. Aged > 18 years
2. Patients with risk factors for CCA (viral hepatitis, parasitic infection, choledochal cyst, primary sclerosing cholangitis, biliary stones, and toxins)
3. Patients who undergo ERCP for confirmation of CBD clearance
4. Dilated common bile duct (> 10 mm)
5. Previous sphincteroplasty, such as major endoscopic sphincterotomy and/or endoscopic papillary balloon dilatation

Exclusion Criteria:

1. Presence of biliary tract cancer
2. Presence of distal CBD stricture
3. Bleeding tendency (INR>1.5 or platelets <50000 mm3)
4. Contraindications of ERCP

We plan to recruit a total of 239 patients, assuming that the detection rate of neoplastic bile duct is about 3.5% by referring to the preceding literature. (one-sample inference for binomial proportions, one-sided test, significance 5%, power 80%)

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