1. A method of contrast enhanced magnetic resonance imaging, the method comprising: (a) acquiring a plurality of magnetic resonance imaging data sets of a subject from a scanner by randomly under-sampling Cartesian k-space; and (b) reconstructing images from the acquired data sets with a split-Bregman minimization of the sum of the L1 norm of the pixel-wise magnitude difference between two successive temporal frames, a fidelity term and a total variation (TV) sparsity term.