General cross-domain networks architecture. Skip and residual connection are omitted for the sake of clarity. y are the under-sampled measurements,in our case the k-space measurements, Ω is the under-sampling scheme,Fis the measurement operator, in our case the Fourier Transform, and x is the recovered solution.

Magnitude reconstruction results for the different fastMRI contrasts at acceleration factor 4. The top row represents the ground truth, the middle one represents the reconstruction from a retrospectively under-sampled k-space,and the bottom row represents the absolute error when comparing the two. The average image quantitative metrics are given for 30 validation volumes.