What is the role of endoscopic ultrasonography for the management of patients with dilated common bile duct?

Purpose: To evaluate the usefulness of EUS in detecting the cause of CBD dilatation.

Methods: We retrospectively analyzed 129 cases with dilated CBD detected with CT (>9mm in diameter) between April 2000 and November 2005. Final diagnoses were determined by endoscopic retrograde cholangiopancreatography and surgical exploration, and all cases diagnosed as only dilated CBD were followed up at least 6 months after diagnosed. As CBD stones and biliopancreatic carcinomas (BPC) are determinant factors for the management of patients with CBD dilatation, we evaluate the diagnostic accuracy in detecting these diseases in the following diagnostic processes. First, we picked up these diseases using CT. When CBD stones were detected, we performed endoscopic treatment without EUS. If CT could not detect any cause or only revealed equivocal findings, we performed EUS additionally and reconsidered the management.

Results: The number of each group was as follows: dilated CBD only, 23; with CBD stones, 55; with BPC, 51 (gallbladder carcinoma 2, extra hepatic bile duct carcinoma 25, carcinoma of the ampulla of Vater 8 and pancreatic carcinoma 16). CT misdiagnosed 11 cases with CBD stones and 4 cases with BPC (extra hepatic bile duct carcinoma 2 and ampullary carcinoma 2). The over all accuracy was 88.4% (114/129). Additional EUS was performed in 85 cases, and diagnosed all 15 misdiagnosed cases correctly. Though CT could reveal equivocal findings in misdiagnosed extra hepatic bile duct carcinomas retrospectively, neither CT nor MRI could detect any findings except for CBD dilatation in non invasive small ampullary carcinomas.

Conclusions: As EUS is superior to CT in detecting CBD stones and occult BPC including small ampullary carcinomas, EUS could be used as the first modality for patients with dilated CBD.