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Abstract #4398

Z-Shim RF Coil Design Enhances Parallel Transmit Performance in Body Imaging at 3T

Xiaoping Wu1, Jinfeng Tian1, Sebastian Schmitter1, Brian Hanna1, Joseph Pfeuffer2, Michael Hamm2, Juergen Nistler2, University of Minnesota University of Minnesota Vaughan1, Kamil Ugurbil1, Pierre-Francois Van de Moortele1

1CMRR, Radiology, University of Minnesota, Minneapolis, MN, United States; 2Siemens Healthcare, Erlangen, Germany

There has been an increasing interest in designing RF arrays with coil elements distributed in all three dimensions so as to also allow B1+ manipulation along the Z direction. Such Z-shim coils have been shown to provide improved RF transmit efficiency for brain imaging, as compared to a conventional coil which has only in-plane encoding capability. In this study, we evaluate the performance of a Z-shim RF array designed for body imaging at 3T and compare it to a conventional array, by designing parallel transmit (pTX) RF pulses with power and SAR regularizations based on electromagnetic simulations of the two coils. Our results show that the Z-shim RF array can give rise to large improvement of flip angle homogenization and/or reduction of SAR for pTX when used for body imaging at 3T, as compared to the conventional coil without Z-encoding capability.