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Abstract #0076

Subject- And Resource-Specific Monitoring and Proactive Management of Parallel RF Transmission

Cem Murat Deniz1, 2, Leeor Alon, 23, Ryan Brown3, Daniel K. Sodickson, 23, Yudong Zhu, 23

1Department of Radiology, Bernard and Irene Schwartz Center for Biomedical Imaging, New York University, New York, NY, United States; 2Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, NY, United States; 3Department of Radiology, Bernard and Irene Schwartz Center for Biomedical Imaging, New York University School of Medicine, New York, NY, United States

Given the constraints imposed by the hardware resource in terms of RF power delivery and reflection handling capabilities, any practical RF pulse used on an MR scanner must be designed with those capabilities on mind. In parallel transmission, coupling and interaction taking place in the multi-port structure as well as in the subject can significantly affect individual channel RF power transmission and the demands placed upon the power amplifiers. By using pre-scan based multi-channel calibration, we designed parallel RF excitation pulses obeying the forward / reflected peak and average power limits of the RF power amplifier. Additionally, global SAR limits were incorporated in the RF pulse design. Results showed that the prediction capability of this new calibration method enables the design of parallel RF excitation pulses respecting strict and multifaceted power limits.

Keywords

accurate achieved acquisition actual addition address affect allowed amplitude appears applicable axial basis became biomedical body built calibrated calibration capability capacity challenging channel channels clinically coil coils column complexity constrained constraint constraints convex correlation decreased delivered delivery design designed designing designs diagonal directional duration efficient eigenvalues elements eliminated enables enforced ensuring entries equivalent evaluated example excitation experimental experimentally extending fidelity finding forward full fully functions global gradient guidance guidelines hardly incorporated indicated individual instant institute least length limits local management matches matching mathematics matrices matrix measured medicine minimization modeling monitoring necessary numerical optimization orthogonalization output parallel patient peak played positive power practice predict predicting prediction predictions press proactive problem projection property pulse pulses radiology reduced reducing reflected reflection represents resource safety sampling scanner school sciences shimming significantly simulations since slice solutions solved space spatial squares strategy structure subject successfully system systems table tolerance transmission transmit unconstrained various verified violated violations virtual