In vivo rapid magnetic field measurement and shimming using single scan differential phase mapping.
In vivo shimming is a powerful tool for alleviating subject-dependent 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.
Toshiba Research and Development Center, Kawasaki, Japan.
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Kanayama
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Kuhara
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Satoh
D000005:Abdomen / Q000473:pathology; D017352:Echo-Planar Imaging; D006257:Head / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008280:Magnetics; D008962:Models, Theoretical; D019047:Phantoms, Imaging