In vivo rapid magnetic field measurement and shimming using single scan differential phase mapping

Abstract

In vivo shimming is a powerful tool for alleviating subjectdependent magnetic field distortions in MRI, although the usually lengthy procedure has limited its use. A magnetic field measurement method called single scan differential phase mapping that can reduce the measurement time of conventional methods by more than half when used with multiple gradient‐recalled echo imaging was developed. An automatic high‐order shimming using the present method was implemented in a commercial MRI system. In vivo field inhomogeneity features and the shimming performances were investigated. The method was found to be useful for improving the quality of echo‐planar images.