Purpose: To intraindividually compare the accuracy of magnetic resonance (MR) cholangiography at 3.0 and 1.5 T for depicting biliary anatomy with intraoperative cholangiography as the reference standard and to compare the image quality for biliary tract visualization at these two field strengths.
Materials and methods: After obtaining institutional review board approval and informed consent, 52 living potential liver donors underwent MR cholangiography at both 1.5 and 3.0 T. The protocol included projectional single-section rapid acquisition with relaxation enhancement (RARE) and respiratory-triggered three-dimensional (3D) fast spin-echo (SE) T2-weighted sequences. Two readers independently analyzed images, scoring the visualization of all first- and second-order biliary branches on a four-point scale and determining the number of visible third-order branches.
Results: MR cholangiography at 3.0 T correctly depicted biliary anatomy in 90.4% of subjects on combined analysis of both sequences by both readers, in 88.5% with projectional RARE images for both readers, and in 84.6% and 88.5% with 3D fast SE images for readers 1 and 2, respectively. MR cholangiography at 1.5 T showed 86.5% and 84.6% accuracy on combined analysis for readers 1 and 2, respectively; 78.8% and 75.0% accuracy on projectional RARE images for readers 1 and 2, respectively; and 84.6% and 86.5% accuracy with 3D fast SE images for readers 1 and 2, respectively. With the projectional RARE sequence, 3.0-T MR cholangiography demonstrated significantly higher mean visualization scores for second-order branches (reader 1: 2.29 vs 1.78, P = .01; reader 2: 2.52 vs 2.10, P < .01) and mean numbers of visible third-order branches (reader 1: 5.53 vs 4.21, P < .01; reader 2: 5.91 vs 3.74, P < .01) than did 1.5-T MR cholangiography.
Conclusion: Compared with 1.5-T MR cholangiography, 3.0-T MR cholangiography did not significantly increase accuracy for identification of biliary anatomy. Projectional RARE images at 3.0 T enabled better visualization of second- and third-order branches than did those at 1.5 T.
(c) RSNA, 2010