Clinical usefulness of gadoxetic acid–enhanced MRI for evaluating biliary anatomy in living donor liver transplantation

Objectives: To determine the incremental value of hepatobiliary-phase-MRC (HBP-MRC) added to T2-magnetic resonance cholangiography (T2-MRC) for evaluating biliary anatomy in living donor liver transplantation (LDLT) and to correlate T2+HBP-MRC findings with surgical results. Methods: A total of 276 donors who underwent T2 and gadoxetic acid–enhanced MRI before right hemihepatectomy for LDLT between January and December 2016 were retrospectively enrolled. Two reviewers evaluated biliary anatomy classification using T2-MRC in the first session and T2+HBP-MRC in the second session. The sensitivity, specificity, and confidence level (5-point scale) of T2-MRC and T2+HBP-MRC for variant biliary anatomy were evaluated. The agreement rates between MRC and operative cholangiography for each biliary anatomy classification and the underestimation rates for multiple bile duct openings (BDOs) for both MRC techniques were evaluated. Results: Of the 276 donors, variant biliary anatomy was observed in 36.2% (100/276). T2+HBP-MRC showed a significantly higher sensitivity for diagnosing variant biliary anatomy than T2-MRC alone (99.0% [99/100] vs. 89.0% [89/100], p = 0.006), with better observer confidence level (4.9 ± 0.3 vs. 4.6 ± 0.7, p < 0.001) and inter-observer agreement (kappa, 0.902 vs. 0.730). Compared with T2-MRC alone, T2+HBP-MRC provided significantly higher agreement with operative cholangiography in biliary anatomy classification (98.6% [272/276] vs. 89.9% [248/276], p < 0.001), and significantly lower underestimation rate for multiple BDOs (5.8% [16/276] vs. 9.4% [26/276], p = 0.002). Conclusion: T2+HBP-MRC might be considered than T2-MRC alone, as a better depiction of biliary anatomic variations, correlated with surgical findings. Key Points: •T2+HBP-MRC predicted variant biliary anatomy more accurately than T2-MRC alone. •T2+HBP-MRC might have clinical usefulness by reducing the underestimation rate of multiple bile duct openings, which requires more complicated biliary anastomoses.