BACKGROUND

In practice, the gradient magnetic fields produced by an MRI scanner are never truly linear. While this non-ideality is most commonly attributed to inaccuracies in spatial encoding, which causes image geometric distortion, it also impacts the accuracy of the signal generated during gradient-based motion encoding, such as diffusion, phase contrast flow, and elastography. While the effect and correction of nonlinearity-induced motion encoding has been characterized in diffusion, there remains a need for methods that can characterize and correct the effects of gradient nonlinearity on magnetic resonance elastography data.

SUMMARY OF THE DISCLOSURE

The present disclosure addresses the aforementioned drawbacks by providing a method for generating an image that depicts mechanical properties of a subject using a magnetic resonance imaging (MRI) system. Motion-encoded magnetic resonance data are acquired from a subject using an MRI system operating a pulse sequence that applies at least one motion-encoding gradient having gradient nonlinearities. Gradient waveform data comprising gradient waveforms of the at least one motion-encoding gradient, and spatial response function data comprising spatial response functions of gradient coils used to apply the at least one motion-encoding data are both provided to a computer system. Gradient nonlinearity corrected displacement data are computed from the motion-encoded magnetic resonance data using the gradient waveform data and the spatial response function data. An image that depicts mechanical properties of the subject is then generated from the gradient nonlinearity corrected displacement data.

The foregoing and other aspects and advantages of the present disclosure will appear from the following description. In the description, reference is made to the accompanying drawings that form a part hereof, and in which there is shown by way of illustration a preferred embodiment. This embodiment does not necessarily represent the full scope of the invention, however, and reference is therefore made to the claims and herein for interpreting the scope of the invention.

