A method for reconstructing an image from undersampled, parallel MRI data
sets acquired with a pulse sequence that samples k-space along radial
trajectories includes the synthesis of training k-space data from the
acquired data. The training k-space data is produced by reconstructing
training images from the fully sampled, central k-space region of the
acquired MRI data sets, and the training k-space data is used in a radial
GRAPPA image reconstruction method to produce an image frame.