Free-breathing Three-dimensional MR Cholangiopancreatography Using Centric k-space Encoding Improved Gallbladder Visualization: A Prospective Study

PURPOSE: MR cholangiopancreatography (MRCP) often suffers from signal loss because of concentrated bile. Gradient-and-spin-echo (GRASE) MRCP reduces this effect but is limited by breath-holding. We developed MRCP with centric order encoding (MRCP-CORE), a novel free-breathing sequence with shorter TE using centric k-space trajectory, T2 preparation, and velocity encoding, and evaluated its ability to visualize gallbladder. METHODS: In this prospective, single-center study, we enrolled 100 consecutive patients who underwent 3 MRCP sequences (MRCP-CORE, conventional MRCP, and GRASE MRCP) on a 3T system. Two blinded radiologists independently assessed the visibility of anatomical structures, artifacts, and overall image quality. SNR, contrast-to-noise ratio, and contrast ratio of the periductal tissue and gallbladder were measured. The Friedman test was used for comparisons; Jonckheere-Terpstra analysis tested the association between the gallbladder visibility and quantitative metrics. RESULTS: Ninety-nine patients (mean age, 68.5 ± 10.9 years; 52 men, 47 women) were evaluated. MRCP-CORE showed significantly higher SNR than conventional and GRASE MRCP (20.9 vs. 17.3 vs. 15.8; P < 0.001). Gallbladder visibility was significantly higher with MRCP-CORE than via conventional MRCP (P = 0.02) and comparable to that via GRASE MRCP (P = 1.00). No significant differences in artifact and overall image quality were observed among sequences. Trend analysis revealed gallbladder visibility was significantly influenced by bile concentration in conventional MRCP (P < 0.001), but not in MRCP-CORE (P = 0.12) or GRASE MRCP (P = 0.43). CONCLUSION: MRCP-CORE enhanced gallbladder depiction compared with conventional MRCP, offering a robust free-breathing alternative to breath-hold GRASE MRCP.