1. A portable magnetic resonance imaging (“MRI”) system, comprising: a magnet assembly extending along a longitudinal axis to define a region configured to receive an object to be imaged and generate a magnetic field that includes known spatial inhomogeneities in a plane transverse to the longitudinal axis of the magnet assembly; a rotator coupled to the magnet assembly and configured to rotate the magnet assembly about its longitudinal axis through a plurality of different rotation angles; a radio frequency (RF) coil for generating RF energy and receiving magnetic resonance signals from an object positioned in the magnet assembly; and a controller configured to: direct the rotator to rotate the magnet assembly through the plurality of different rotation angles; direct the RF coil to generate RF energy and receive responsive magnetic resonance signals at each rotation angle to acquire imaging data by reading out magnetic resonance signals while the magnet assembly is at each of the plurality of different rotation angles; correlate the known spatial inhomogeneities in the magnetic field generated by the magnet assembly with modulations in a phase of the magnetic resonance signal to determine spatial encoding information imaging data; and reconstruct an image of the object using the imaging data and the spatial encoding information.