Michael R. Hartley

Correction of geometric distortion in MRI phase and phase difference images

In an MRI system NMR data is acquired and an image is reconstructed based on the net phase or phase difference of spins at locations in the imaged object. The phase or phase difference image is corrected for errors caused by non-linearities in one or more of the gradient fields. The phase or phase difference image values are weighted with spin signal magnitude image values and their locations warped to reflect gradient field non-linearity. The warped values are remapped to the image pixel locations and converted back to phase values by dividing by an average spin signal magnitude. In this manner geometric distortion caused by non-uniform magnetic field gradients are corrected without loss of quantitative phase or phase difference information.