This study is prospective, multicenter study for identify the characteristics of asymptomatic common bile duct stones and effectiveness of treatment.

There is no conflcts for treatment of symptomatic common bile duct stone. As more imaging examination such as healthy screening, more asymptomatic common bile duct stone patients are found. Current guideline for aymptomatic common bile duct stone is removal using endoscopic retrograde cholangiopancreatography. However, the previous studies that support this guideline included patients who just underwent cholecystectomy and were diagnosed as common bile duct stone. There is no prospective study for identify the treatment effectiveness of common bile duct stone removal in asymptomatic patients who are dignosed in healthy screening. Therefore, we are going to find the effectiveness of common bile duct stone removal by comparing questionnarie before and after removal of common bile duct stone in asymptomatic and incidentally found common bile duct stone patients. In addition, we are going to follow up patients who do not want to undergo common bile duct stone removal and find the rate of cholangitis risk. We also want to identify extact complication rate for endoscopic retrograde pancreatocholangiographic procedures in asymptomatic common bile duct stone.

Inclusion Criteria:

• diagnosed as common bile duct stone by image modality examination
• agreement for this study enrollment

Exclusion Criteria:

• no definite common bile duct stone by image modality examination
• symptomatic patients who complain with fever/abdominal pain that compatible with common bile duct stone related symptom
• previously diagnosed as pancreatobiliary malignancy
• previously treated by endoscopic or percutaneous treatment for bile duct stones
• severe cardio or pulmonary disease
• pregnancy or possibility of pregnancy
• who do not agree with study enrollment

Healthy volunteers who have common bile duct stones without cholangitis symptom