Intraductal US in evaluation of biliary strictures without a mass lesion on CT scan or magnetic resonance imaging: significance of focal wall thickening and extrinsic compression at the stricture site

Background and Objective: The clinical utility of intraductal US (IDUS) for evaluating biliary strictures has been limited because of a lack of easily recognized morphologic criteria to distinguish benign and malignant strictures. We studied the clinical value of 2 easily assessed IDUS findings: wall thickness and extrinsic compression at the stricture site. Design and Setting: A retrospective, single-center study. Patients and Methods: Forty-five patients without an identifiable mass on CT/magnetic resonance imaging, who underwent ERCP/IDUS for evaluation of biliary strictures were studied. IDUS pictures were reviewed specifically to measure wall thickness and to look for extrinsic compression at the stricture site. Main Outcome Measurements and Results: The mean age of the patients was 64.2 +/- 13.3 years. Thirty patients had jaundice at presentation, and in 15 patients a stricture was suspected on imaging. The mean length of biliary strictures was 15.1 +/- 7.8 mm. Strictures were distal (distal common bile duct) in 25 patients and proximal (mid/proximal common bile duct or common hepatic duct) in 20 patients. Fourteen strictures were finally diagnosed to be malignant. Strictures in 20 patients were caused by extrinsic compression, and tissue diagnosis was readily obtained by EUS-FNA in all these patients. Of 25 strictures without extrinsic compression, 6 were malignant (wall thickness 9-16 mm) and 19 were benign (wall thickness <= 9 mm). Bile duct wall thickness <= 7 mm at the stricture site, in the absence of extrinsic compression, had a negative predictive value of 100% for excluding malignancy in this cohort. Limitations: Retrospective study and relatively small number of patients. Conclusions: Evaluation of wall thickness and the presence of extrinsic compression at the site of biliary strictures by IDUS can help in further management of these patients.