1. A method for reconstructing an actual image from sensitivity encoded magnetic resonance imaging (MRI) data capable of being represented in a frequency domain, the frequency domain comprising at least a phase-encoding direction and a slice-encoding direction, the phase-encoding and slice-encoding directions corresponding to a first spatial dimension and a second spatial dimension, respectively, the method comprising: based on a reduced MRI data set, acquired from each of two or more receiver coils, the reduced MRI data set configured to be represented in a first portion of the frequency domain, wherein the MRI data set is undersampled in at least the phase-encoding direction; determining reconstruction coefficients for each of the two or more receiver coils, the reconstruction coefficients being spatially varying in at least the second spatial dimension which corresponds to the slice-encoding direction; determining a reconstructed MRI data set, configured to be represented in a second portion of the frequency domain, for each of the two or more receiver coils by combining the reconstruction coefficients and the reduced MRI data set from at least one of the two or more receiver coils, the second portion comprising representative locations in the frequency domain wherein the reduced MRI data set has not been acquired; determining a complete MRI data set for each of the two or more receiver coils by combining the reduced MRI data set and the reconstructed MRI data set; and outputting at least a portion of the complete MRI data set to an output device configured for display or a computer readable medium.