Bile duct obstruction and choledocholithiasis: diagnosis with MR cholangiography.

PURPOSE To evaluate the accuracy of magnetic resonance (MR) cholangiopancreatography in the diagnosis of bile duct obstruction. MATERIALS AND METHODS One hundred twenty-six patients with clinically suspected bile duct obstruction underwent MR cholangiopancreatography with heavily T2-weighted fast spin-echo sequences. Reviewers were blinded to clinical and imaging findings. RESULTS Seventy-nine patients had biliary obstruction that was diagnosed with MR cholangiopancreatography in 72 patients for a sensitivity of 91%, specificity of 100%, and overall accuracy of 94%. Thirty-two patients had choledocholithiasis that was diagnosed with MR cholangiopancreatography in 26 patients for an accuracy of 94%, sensitivity of 81%, specificity of 98%, positive predictive value of 93%, and negative predictive value of 94%. Fourteen patients had malignant obstruction that was diagnosed with MR cholangiopancreatography in 12 patients for a sensitivity and a positive predictive value of 86%, specificity and negative predictive value of 98%, and accuracy of 97%. CONCLUSION MR cholangiopancreatography is a noninvasive technique with excellent accuracy in the diagnosis of bile duct obstruction and its causes.