Fast electromagnetic and RF circuit co-simulation for passive resonator field calculation and optimization in MRI

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Electromagnetic (EM) Field Theory
• Computational Physics

Background:

• Passive resonators are crucial for manipulating radiofrequency (RF) fields in MRI.
• Optimizing complex passive resonator arrays via full-wave electromagnetic (EM) simulations is computationally intensive.

Purpose of the Study:

• To develop and validate a novel co-simulation framework for the efficient analysis and optimization of passive resonators in MRI.
• To enable rapid optimization of passive resonator parameters for enhanced B1 field homogeneity.

Main Methods:

• A co-simulation framework was developed, integrating EM and RF circuit simulations.
• Passive resonators' lumped components were replaced by ports in a single full-wave EM simulation.
• Circuit-level computations evaluated various capacitor/inductor configurations, coupled with a genetic algorithm for optimization.

Main Results:

• The co-simulation framework demonstrated high accuracy, with results showing <1% relative error compared to full-wave EM simulations.
• Optimization of passive resonator arrays using the genetic algorithm was completed in under 5 minutes.
• The method was successfully validated on single-loop and two-loop resonator arrays using phantom and human head models.

Conclusions:

• This work presents the first systematic application of co-simulation for passive resonator design in MRI.
• The developed framework offers a computationally efficient, accurate, and scalable solution for passive RF structure optimization.
• The approach significantly reduces computational burden, facilitating advanced passive RF coil development for MRI applications.