Frame-by-frame plots of MSE for two-step OMP, k-t FOCUSS, and k-t ISD with R = 3 for the 5-coil dataset (top left), R = 4 for the single-coil dataset (top right), R = 8 for the 12-coil dataset (bottom left), and R = 8 for the 15-coil dataset (bottom right). The solid lines are for k-t ISD, dotted lines for k-t FOCUSS, and dashed lines for two-step OMP.