EM Simulation Model of a Clinically-Used RF Head Coil at 7 T

Purpose: The purpose of this study is to create an EM simulation model for the NOVA 8Tx/32Rx RF head coil to further develop its applications in research and clinical use. The developed EM model has been made publicly available. Methods: The coil was modeled as a combination of microstrips in Ansys HFSS. The currents on these microstrips were optimized to match the manufacturer-provided complex magnetic fields inside the coil. The accuracy with which this match can predict the (Formula presented.) magnitudes for a phantom with different permittivity and shape was verified using experimental data from a 7 T scanner. Results: Accurate predictions of both (Formula presented.) and SAR were obtained using the proposed simulation model, where the structural similarity index for the manufacturer-provided data was greater than 98% for different RF shim patterns. The experimental validation of the model yielded a (Formula presented.) structural similarity of over 90% and the average RMS error for random RF excitation scenarios was found as 0.3 µT/ (Formula presented.). Conclusion: In this study, we designed an EM simulation model of the NOVA RF transmit head coil. We confirmed the reliability of the model by comparing its predictions with experimental data, and validated that the model can estimate (Formula presented.) distributions in different phantoms for a variety of excitation patterns.