High temporal resolution retrospective motion correction with radial parallel imaging

A method for motion correction in multicoil imaging applications, involving both data collection and reconstruction, is presented. A bit-reversed radial acquisition scheme, in conjunction with a rapid self-calibrated parallel imaging method, Generalized auto-calibrating partial parallel acquisition (GRAPPA) operator for wider radial bands (GROWL), is used to achieve motion correction at a high temporal resolution. View-by-view in-plane motion correction is achieved in 2D imaging, while 3D motion correction is achieved for every two consecutive slice-encoding planes in 3D imaging. In the proposed technique, GROWL contributes in two aspects: First, a central k-space circle/cylinder used as the motion-free reference is generated from a small number of radial lines/planes; Second, undersampled k-space regions resulting from rotation and inconsistent (e.g. intraview and nonrigid body) motion can be filled in. When compared with navigator-based motion correction methods, the proposed method does not prolong scan time and can be applied to short-TR sequences. Magn Reson Med, 2011.