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

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Electromagnetic (EM) Simulation
• RF Coil Design

Background:

• The NOVA 8Tx/32Rx RF head coil is crucial for advanced MRI research and clinical applications.
• Accurate electromagnetic (EM) simulation models are essential for optimizing RF coil performance and understanding B1+ field distribution.

Purpose of the Study:

• To develop a validated EM simulation model for the NOVA 8Tx/32Rx RF head coil.
• To make the developed EM model publicly available for broader research and clinical use.

Main Methods:

• The coil was modeled using microstrips in Ansys HFSS, optimizing currents to match manufacturer-provided magnetic fields.
• Model accuracy was verified by predicting B1+ magnitudes in phantoms of varying permittivity and shape using experimental data from a 7T scanner.

Main Results:

• The EM simulation model achieved >98% structural similarity with manufacturer data for B1+ and SAR predictions across different RF shim patterns.
• Experimental validation showed >90% B1+ structural similarity and an average RMS error of 0.3 µT/√W for random RF excitations.

Conclusions:

• A reliable EM simulation model for the NOVA RF transmit head coil was successfully designed.
• The model's predictions were confirmed against experimental data, demonstrating its capability to estimate B1+ distributions in diverse phantoms and excitation patterns.