System and method of compensation of radio frequency spatial encoding misalignment errors due to gradient non-linearity in magnetic resonance imaging

Radiofrequency (RF) spatial encoding misalignment errors due to gradient non-linearity in magnetic resonance imaging are compensated by using realistic values for frequency offset and bandwidth rather than ideal values. The true magnetic field produced by the gradient coils in space are taken into account to encode the frequency band and offset of the RF pulse corresponding to the desired spatial encoding position and slice thickness. The method is applicable to any positionally frequency encoded radiofrequency (RF) pulses including: slice or slab excitation pulses, inversion pulses, spin echo or refocusing pulses, and spatial saturation pulses. The realistic field may be determined from modelling or measurements of the gradient coils. The bandwidth may be found by computing the spread of frequencies over a 3D slab. The standard deviation or full width at half maximum of a frequency histogram may be used. The offset may be computed as the average frequency on an axis normal to the slab.