Evolution of bile-duct dilatation in liver-transplanted patients with biliary stricture: an MRC-based study.

Purpose: To assess whether bile-duct dilatation is influenced by the type of biliary stricture and time from liver-transplantation in LTPs. Methods and Materials: Eighty-five 3D-MRCs performed over a 2-years period on 54 LTPs with proven bile-duct strictures were retrospectively evaluated. Diameter was measured on thin source images at the common bile duct (CBD), right hepatic duct (RHD), left hepatic duct (LHD), anterior- and posterior-right hepatic ducts (aRHD,pRHD), left lateral and medial ducts (LL,LM). Presence of dilatation was assessed for peripheral ducts (2-mm treshold). Data were stratified according to the type of stricture (all types, anastomotic, ischaemic-like, and mixed) and compared: (i) between two groups based on the timing of MRC from liver transplantation (OLT) (within or after 1 year, respectively); (ii) within types of strictures. Results: Except for the CBD and peripheral ducts, the biliary tree resulted slightly dilated within 1-year from OLT (2.9±1.4-4.7±3.1 mm), especially at LHD and pRHD (4.7±3.1 and 3.6±1.9 mm, respectively). A trend towards increase in diameter after 1-year characterized all biliary ducts, showing statistical significance for all types (p=0.0005-0.0351;t-test) and mixed-type (0.0002-0.0394;t-test) of strictures. Increase was homogeneous for all biliary ducts and types of stricture (mean=1.5±0.5 mm). Biliary dilatation occurred more frequently after 1-year in peripheral ducts (p<0.05;Fisher-exact test) for all types of stricture. No significant difference in mean diameter was shown within types of strictures (p>0.05;ANOVA). Conclusion: Upstream dilatation in LTPs with bile-duct stricture is higher in late post-liver-transplantation period, especially for the mixed-type. MRCP is optimal as a panoramic first-line imaging evaluation.