EXTRACT (Extrapolation and Correlation): A New Ultra-Rapid Motion Correction Technique

W. Lin, H. K. Song Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States Introduction: Post-processing techniques requiring no additional navigator data have been successfully demonstrated for motion correction in MRI [1-3]. However, high computational costs typically associated with these methods have limited their application. For example, a 2-D translational correction alone could take several minutes to complete [3], and time would be much longer if rotational motion was also considered. This work proposes a new and efficient post-processing technique for motion correction, called k-space EXTRapolation And CorrelaTion (EXTRACT). For each k-space segment, the method first estimates a motion-free reference by extrapolating from a previously motion-corrected region. Motion information is then recovered by correlating the acquired motion-corrupted data with the extrapolated “motionless” data in an efficient manner. A 2-D translational motion correction is typically completed in a few seconds, regardless of the range of the motion.