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Abstract #4399

Simultaneous Excitation of Distinct Electromagnetic Modes Using a Tx Array

Yujuan Zhao1, Sossena Wood1, Tiejun Zhao2, Narayanan Krishnamurthy1, Tamer S. Ibrahim1

1University of Pittsburgh, Pittsburgh, PA, United States; 2Siemens Medical Solutions, Pittsburgh, PA, United States

The inhomogeneous distribution of the magnetic field B1+ at ultrahigh field imaging (≥7T MRI) is a significant challenge for the RF coil design. In this work, a new excitation paradigm is presented utilizing 20-channel Tic-Tac-Toe (TTT) based RF transmit array design where the 20 elements are combined into 5 different groups in order to excite 20 distinct modes with longitudinal spatial selectivity. Any 5 of these modes can be simultaneously excited. The optimization shimming method has been used to find a uniform excitation pattern under SAR constraints. The results are successfully tested on a 7T MRI scanner using phantoms and in-vivo (7 human subjects.)