Role of Endoscopic Ultrasound in Diagnosis of Unexplained Distal Common Bile Duct Stricture

Background: Determining the etiology of distal biliary strictures lacking a recognizable cause on imaging is crucial for appropriate therapy. Objective: This study aimedto evaluate the efficacy of endoscopic ultrasound (EUS) in diagnosing distal biliary strictures that were not diagnosed by cross-sectional imaging modalities like computed tomography or magnetic resonance imaging. Patients and Methods: Prospective study included 80patients with unexplained distal biliary strictures diagnosed using Magnetic Resonance Cholangiopancreatography (MRCP), Endoscopic Retrograde Cholangiopancreatography (ERCP), CT, or MRI done EUS.
Results: 80 patients (50 males mean age 57.9 ± 9.8 years) were studied. Based on EUS findings, 51 patients were diagnosed with malignant strictures (63.75%) (21 distal cholangiocarcinomas, 17 pancreatic head masses, 11 ampullary mass lesions, and 2 intraductal papillary mucinous neoplasms), and the remaining patients were diagnosed as benign strictures (36.25%). Receiver Operating Characteristic (ROC) analysis between malignant and benign strictures for distal Common Bile Duct (CBD) wall thickness showed a cut-off value of > 3.2 (Sensitivity of 80.39%, specificity of 89.66%, positive predictive value (PPV) of 93.2% negative predictive value (NPV) of 72.2% and accuracy of 85.7%).
Conclusion: EUS is a promising investigational procedure for patients with challenging distal CBD strictures, and can predict the nature of the strictures whether benign or malignant.