Intraductal ultrasound for the evaluation of patients with biliary strictures and no abdominal mass on computed tomography

Background and study aims: Endoscopic retrograde cholangiopancreatography (ERCP) is the diagnostic procedure of choice in patients with biliary strictures and no culprit mass lesion on abdominal imaging, but it is limited in its diagnostic accuracy. The aim of this prospective study was to determine the value of intraductal ultrasound (IDUS) in distinguishing between benign and malignant biliary strictures in this clinical setting. Patients and methods: Sixty-one patients with painless jaundice and no mass lesion on abdominal computed tomography, who were found to have a biliary stricture at ERCP, underwent IDUS with a high-frequency (20-MHz) wire-guided probe. Histopathological confirmation or clinical follow-up was used to establish the final diagnosis. The diagnostic performances of IDUS, ERCP, and IDUS plus ERCP in the identification of malignant strictures were evaluated. Results: Forty-three patients had malignant strictures and 18 had benign strictures. ERCP produced 25 false-negative diagnoses, 22 of which were identified as malignant by IDUS. IDUS provided seven false-negative and three false-positive diagnoses. The proportion of patients with malignant strictures who tested positive with IDUS was 2.06 times that of ERCP (95% CI, 1.37-3.10; 83.3% vs. 40.5%, P=0.0004). When used in conjunction, IDUS increased the accuracy of ERCP from 58% to 90%. Patients with operable lesions on IDUS and no contraindication to surgery underwent resection; most patients with pancreatic parenchymal invasion on IDUS underwent EUS, which identified a pancreatic mass in more than 50% of cases. Patients with negative IDUS and a low clinical suspicion for malignancy were treated endoscopically, while a more aggressive work-up was performed in all patients with high pretest probability, regardless of the IDUS results. Conclusions: IDUS is a valuable adjunct to ERCP in the characterization of biliary strictures in patients who present with painless jaundice in the absence of a culprit mass on abdominal imaging.