1. A method for producing a map of a static magnetic field (B 0 ) of a magnetic resonance imaging system, the method comprising: a) forming a first dataset by acquiring, with the MRI system, a first plurality of different echo signals occurring at a respective plurality of different echo times; b) forming a second dataset by acquiring, with the MRI system, a second plurality of different echo signals occurring at a respective plurality of different echo times, wherein the second dataset includes signals resulting from a magnetization transfer (MT) between free water and bound molecules; c) generating MT-weighted maps using the first dataset and the second dataset; d) determining, using the MT-weighted maps, a phase difference between the first plurality of different echo signals; and e) using the phase differences, generate a corrected map of the static magnetic field (B 0 ) of the MRI system.