Correction for gradient nonlinearity in continuously moving table MR imaging.

Abstract

Recently, a number of methods have been demonstrated for large field of view MR imaging using continuous table motion. As with conventional, fixed-table MRI, the spatial encoding is performed using magnetic field gradients. However, it is demonstrated in this work that as a consequence of every measurement being made at a slightly different displacement between the object and the gradient field, gradient nonlinearities are manifest as blurring in addition to spatial distortion. Moreover, the blurring is spatially dependent. It is also shown that correcting all phase-encoding steps individually or in groups can reduce these effects. Phantom and in vivo results are shown which demonstrate the effectiveness of the correction.