Comparison of Non-rigid Motion Compensated Reconstructions for 3d Abdominal Mri

INTRODUCTION: Respiratory motion is a major challenge for 3D abdominal MRI. Respiratory navigator gating is commonly used to compensate for motion, but leads to low scan efficiency. Recently, a free-breathing motion compensated technique was proposed that estimates 3D non-rigid motion from undersampled reconstructed images. This technique compensates motion by warping the undersampled images to a common respiratory position (image warping). An alternative approach is to use the estimated motion fields to correct the corrupted k-space directly in the reconstruction process, using a general matrix description (GMD) of the acquisition. Here we propose to use the GMD approach to compensate for motion in 3D abdominal MRI and compare its performance with the image warping framework. Results on 5 volunteers show that the GMD approach yields sharper images and correctly reconstructs small structures in comparison with the image warping approach and gated reconstruction.