Theoretical Basis of Projection Based Shim Estimation

Daniel Nicolas Splitthoff¹, Maxim Zaitsev¹

Projections have been suggested for estimating B0 inhomogeneities. A detailed analysis of the phase difference of projections is given and put into the framework of linear algebra. The insights gained from this analysis lead to the conclusion that for proper detection of inhomogeneities the cross talk of the different orders need to be taken into account. We here present a solution of how to measure the cross talk when no further a priori information is available and show the benefit in a phantom measurement.