Efficacy of Endoscopic Ultrasonography in Evaluation of Undetermined Etiology of Common Bile Duct Dilatation on Abdominal Ultrasonography

The cause of common bile duct (CBD) dilatation cannot be determined by imaging modalities in many patients. The aim of this study was to assess the value of endoscopic ultrasonography (EUS) in detecting the cause of CBD dilatation in patients in whom ultrasonography could not demonstrate the cause of dilation.
Prospectively, 152 consecutive patients who were referred for evaluation of dilated CBD (diameter ≥7 mm) of undetermined origin by ultrasonography were included in this study. All the patients underwent EUS. Final diagnoses were determined by using endoscopic retrograde cholangiopancreatography (ERCP), EUS-guided fine needle aspiration (FNA), surgical exploration, or follow-up for at least 10 months. Patients with choledocholithiasis were referred for ERCP and sphincterotomy, and patients with operable tumors were referred for surgery. Patients with inoperable tumors underwent biliary stenting with or without chemoradiotherapy.
152 patients (54% female) with dilated CBD were included. Mean (±SD) age of the patients was 60.4 (±17.3) years. The mean CBD diameter for all study group in transabdominal ultrasonography and EUS were 11.7 millimeter and 10.1 millimeter, respectively. Most of the patients with dilated CBD and abnormal liver function test (LFT) had an important finding in EUS and follow-up diagnosis including peri-ampullary tumors. Mean diameter of CBD in patients with and without abnormal LFT were 10.5 IU/L and 12.1 IU/L, respectively. Final diagnoses included choledocholithiasis in 32 (21.1%), passed CBD stone in 35 (23%), opium-induced CBD dilation in 14 (9.2%), post-cholecystectomy states in 20 (13.1%), ampullary adenoma/carcinoma in 15 (15.8%), cholangiocarcinoma in 14 (9.2%), and pancreatic head cancer in 9 (5.9%) patients. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of EUS for patients with abnormal EUS were 89.5%, 100.0%, 100.0%, 91.2%, and 90.9%, respectively.
After diagnosis of CBD dilation by transabdominal ultrasonography, EUS may be a reasonable choice for determining the etiology of dilated CBD and tumor staging.