Usefulness of 3D balanced turbo-field-echo MR sequence evaluating the branching pattern of the intrahepatic bile ducts: comparison with drip infusion CT cholangiography

Purpose: For liver surgery, it is crucial to preoperatively examine the course of the right posterior bile duct. While MR cholangiopancreatography (MRCP) can only visualize the bile ducts, 3D balanced turbo-field-echo (BTFE) sequence clearly depicts the bile ducts and portal veins as well as drip infusion CT cholangiography (DIC-CT), without contrast media. We evaluated whether BTFE could substitute for DIC-CT. Materials and methods: Thirty patients undergoing MRCP and BTFE on 1.5-T MR and DIC-CT were evaluated. Two readers retrospectively evaluated the branching pattern (supra-type: A–C or infra-type: D–E) and scored the degree of confidence and motion artifacts using a 3-point scale for the three 2-mm-thick reconstructed images. Results: The bile duct diameter did not differ between DIC-CT and MRCP (p = 0.07). Five patients (17%) had intrahepatic biliary dilatation (>3 mm). The A, B, C, D, and E types were diagnosed in 21, 6, 1, 1, and 1 patient, respectively (28 supra-types and 2 infra-types) on DIC-CT. For DIC-CT, MRCP, and BTFE, the mean motion artifact scores were 3.0/3.0, 2.7/2.6, and 2.9/2.8, respectively. The mean diagnostic confidence scores were 2.9/2.9, 2.4/2.4, and 2.9/2.8, respectively, with no difference between DIC-CT and BTFE. The concordance between DIC-CT and BTFE was high (infra- or supra-type: κ = 1.00/1.00, A–E: κ = 0.86/0.66), but it was poor between DIC-CT and MRCP (infra- or supra-type: κ = 0.35/−0.05, A–E: κ = 0.33/0.41) for both readers. Conclusions: Similar to DIC-CT, the BTFE MR sequence had high diagnostic accuracy regarding the branching pattern of the intrahepatic bile duct, especially for the supra/infraportal type.