First In Vivo Results using Decoupled Projection Based Shimming

Daniel Nicolas Splitthoff¹, Maxim Zaitsev¹

It is well known that Echo Planar Imaging (EPI) suffers strongly from geometric distortions caused by B0 inhomogeneities. As a remedy it has for example been suggested to correct for the distortions in the image processing, based on prescans. Nevertheless such approaches relay on the assumption that the field inhomogeneities due not change during the measurement, which is not necessarily the case. We here present an improved version of projection based real time linear shim detection and correction, that takes into account the cross talk between axes, when the orthogonality is broken due to inhomogeneous magnetisation distributions. The applicability of the method is shown in in vivo correction of motion induced shim changes.