A method and associated system of correcting errors caused by non-linearities in a gradient field profile of a gradient coil in a magnetic resonance imaging (MRI) system, comprising obtaining a non-linearity tensor 302 at each voxel within the imaging space using a computer model of the gradient coil 308; correcting motion sensitive encoding using the non-linearity tensor 316; and generating a corrected image using the corrected motion sensitive encoding 318. The non-linearity tensor may be calculated 312 from a magnetic field gradient at each corresponding voxel in real time. The calculated magnetic field gradient corresponding to a discontinuous sample of voxels within the imaging space may be stored 314 in a low resolution three-dimensional array and interpolated to obtain the magnetic field gradient at each voxel. Correcting the motion sensitive encoding may comprise deriving a corrected diffusion tensor using the non-linearity tensor. Correcting the motion sensitive encoding may comprise calculating a corrected b-value using the non-linearity tensor. Obtaining the non-linearity tensor may comprise retrieving said tensor from a memory of the MRI system 304. The corrected image generated may be a correct velocity encoding imaging sequence.
Method of correcting gradient nonuniformity in gradient motion sensitive imaging applications