Purpose: To reduce irregular respiratory motion-induced artifacts in free-breathing prospective navigator-triggered three-dimensional (3D) MR cholangiopancreatography (MRCP).
Materials and methods: A reference respiration model was estimated from the first-five respiration periods during the initial navigator scan. With the navigator information acquired before and after triggering, the un-acquired diaphragm position during the actual imaging was interpolated using the amplitude-scaled reference model. Craniocaudal translational motion during imaging was retrospectively corrected using the estimated diaphragm position. T2-weighted 3D MRCP data were acquired from 17 healthy volunteers. For quantitative analysis, contrast-to-noise ratio (CNR) and relative contrast (RC) of the biliary tree and gallbladder were compared using the paired t-test.
Results: The CNR and RC of the biliary tree and gallbladder were significantly higher (P < 0.05) in the maximum intensity projection images after motion compensation.
Conclusion: The proposed algorithm can be an effective tool to reduce the irregular respiratory motion-induced artifacts in 3D MRCP imaging.