Nonrigid motion modeling of the liver from 3-D undersampled self-gated golden-radial phase encoded MRI. http://dx.doi.org/10.1109/TMI.2011.2181997

Abstract

Magnetic resonance imaging (MRI) has been commonly used for guiding and planning image guided interventions since it provides excellent soft tissue visualization of anatomy and allows motion modeling to predict the position of target tissues during the procedure. However, MRI-based motion modeling remains challenging due to the difficulty of acquiring multiple motion-free 3D respiratory phases with adequate contrast and spatial resolution. Here, we propose a novel retrospective respira- tory gating scheme from a 3D undersampled high-resolution MRI acquisition combined with fast and robust image registrations to model the non-rigid deformation of the liver. The acquisition takes advantage of the recently introduced Golden-Radial Phase Encoding (G-RPE) trajectory. G-RPE is self-gated, i.e. the res- piratory signal can be derived from the acquired data itself, and allows retrospective reconstructions of multiple respiratory phases at any arbitrary respiratory position. Non-rigid motion modeling is applied to predict the liver deformation of an average breathing cycle. The proposed approach was validated on 10 healthy volunteers. Motion model accuracy was assessed using similarity-, surface- and landmark-based validation methods, demonstrating precise model predictions with an overall target registration error of T RE = 1.70 ± 0.94mm which is within the range of the acquired resolution.