Recurrent common bile duct stones composed of ursodeoxycholic acid: a report of four cases.

Ursodeoxycholic acid (UDCA) is often used to treat cholesterol gallstones. UDCA makes cholesterol stones soluble, thereby improving biliary emptying. Conversely, however, UDCA can also form stones via an unknown mechanism, as shown in a few previous reports of cholangitis caused by the formation of UDCA stones in the common bile duct (CBD). We herein report four cases of recurrent cholangitis resulting from UDCA stones. The withdrawal of UDCA administration was highly effective in these patients. The details of these four cases suggest that clinicians must rethink the indications for UDCA treatment in cases in which cholangitis caused by CBD stones frequently recurs over a short period of time.

Common bile duct stones on multidetector computed tomography: attenuation patterns and detectability.

AIM: To investigate the attenuation patterns and detectability of common bile duct (CBD) stones by multidetector computed tomography (MDCT). METHODS: Between March 2010 and February 2012, 191 patients with suspicion of CBD stones undergoing both MDCT and endoscopic retrograde cholangiopancreatography (ERCP) were enrolled and reviewed retrospectively. The attenuation patterns of CBD stones on MDCT were classified as heavily calcified, radiopaque, less radiopaque, or undetectable. The association between the attenuation patterns of CBD stones on MDCT and stone type consisting of pure cholesterol, mixed cholesterol, brown pigment, and black pigment and the factors related to the detectability of CBD stones by MDCT were evaluated. RESULTS: MDCT showed CBD stones in 111 of 130 patients in whom the CBD stones were demonstrated by ERCP with 85.4% sensitivity. The attenuation patterns of CBD stones on MDCT were heavily calcified 34 (26%), radiopaque 31 (24%), less radiopaque 46 (35%), and undetectable 19 (15%). The radiopacity of CBD stones differed significantly according to stone type (P < 0.001). From the receiver operating characteristic curve, stone size was useful for the determination of CBD stone by MDCT (area under curve 0.779, P < 0.001) and appropriate cut-off stone size on MDCT was 5 mm. The factors related to detectability of CBD stones on MDCT were age, stone type, and stone size on multivariate analysis (P < 0.05). CONCLUSION: The radiopacity of CBD stones on MDCT differed according to stone type. Stone type and stone size were related to the detectability by MDCT, and appropriate cut-off stone size was 5 mm.