Clinical Feasibility of Gadoxetic Acid-Enhanced Isotropic High-Resolution 3-Dimensional Magnetic Resonance Cholangiography Using an Iterative Denoising Algorithm for Evaluation of the Biliary Anatomy of Living Liver Donors.

Abstract

The aim of this study was to evaluate the clinical feasibility of gadoxetic acid-enhanced isotropic high-resolution (IHR) 3-dimensional (3D) T1-weighted (T1W) magnetic resonance cholangiography (MRC) using an iterative denoising (ID) algorithm for evaluation of the biliary anatomy of living liver donors in comparison with conventional 3D multislice T2-weighted (T2W) MRC. In this institutional review board-approved retrospective study, a total of 75 living liver donors who underwent conventional 3D multislice T2W-MRC and IHR-3D-T1W-MRC on a 3 T scanner and subsequent right hepatectomy for liver donation were included. Isotropic high-resolution T1W-MRCs were obtained in both axial and coronal planes using the 3D VIBE Dixon sequence and an ID algorithm implemented with wavelet thresholding of 3D complex-valued data of the noise level, g-factor, and k-space filtering. Thereafter, 3 board-certified radiologists independently reviewed the examinations for visibility and sharpness of the bile ducts (BDs), as well as overall image quality on a 5-point scale. For diagnostic performance, anatomic variations of the BD, length of right hepatic duct, and the expected number of BD openings at right hepatectomy were also recorded. As the reference standard, BD variation was determined by surgeons in consensus using intraoperative real-time fluorescent cholangiography. Mean acquisition times of 3D-T2W-MRC and IHR-T1W-MRC were 367 seconds and 17 seconds (P < 0.001), respectively. Compared with 3D-T2W-MRCs, IHR-T1W-MRCs yielded significantly improved visibility and sharpness of all evaluated intrahepatic bile ducts (all Ps < 0.05), and higher overall image quality (P < 0.01). The IHR-T1W-MRCs also demonstrated significantly higher agreement in BD variation (87.6% vs 81.3%, P = 0.03) and expected BD openings (76.9% vs 70.2%, P = 0.006) than 3D-T2W-MRC compared with the reference standard. Interobserver agreement in estimating the length of right hepatic duct, IHR-T1W-MRC showed excellent interobserver agreement (intraclass correlation coefficient, 0.94), whereas 3D-T2W-MRC showed good interobserver agreement (intraclass correlation coefficient, 0.78). Isotropic high-resolution T1W-MRCs with ID provided significantly improved BD image quality and more accurate depiction of the BD anatomy and BD openings at right donor hemihepatetomy than 3D-T2W-MRC.