Bile duct strictures after hepatobiliary surgery: assessment with MR cholangiography

Abstract

Purpose: To establish the accuracy of magnetic resonance (MR) cholangiography for diagnosis of postsurgical bile duct strictures.

Materials and methods: Sixty-seven patients suspected of having bile duct strictures after liver transplantation (n = 54), cholecystectomy (n = 8), hepatic resection (n = 4), or pancreaticoduodenectomy (n = 1) underwent MR cholangiography. Thick-slab single-shot fast spin-echo (repetition time msec/echo time msec, 4,500/940) imaging was performed in the coronal through sagittal planes with rotation in 10 degrees increments, and contiguous thin-section images were obtained in the transverse and the optimal coronal oblique planes by using half-Fourier rapid acquisition with relaxation enhancement (1,900/96). Three blinded observers independently reviewed the MR images and recorded diagnostic features including presence of biliary stricture by using a five-point confidence scale. Receiver operating characteristic analysis was used to measure the accuracy of MR cholangiography. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. Final diagnosis was established at surgery (n = 29) and direct cholangiography (23 of 29) or at direct cholangiography, liver biopsy, and/or serial liver function tests (n = 38).

Results: Thirty-three of 67 patients had strictures confirmed with the reference standard. MR cholangiography enabled correct diagnosis and depicted the site of strictures in all cases. Findings of stricture at MR cholangiography were false-positive in five patients with moderate duct dilatation and caliber change at the level of the anastomosis. Mean accuracy, sensitivity, specificity, PPV, and NPV were 94%, 97%, 74%, 86%, and 96%, respectively.

Conclusion: MR cholangiography is as sensitive as direct cholangiography for the assessment of bile duct strictures after hepatobiliary surgery but may lead to overestimation of the importance of duct dilatation and caliber change.