Electromagnetic simulations for Magnetic Resonance radio frequency coils

Magnetic Resonance Imaging and Magnetic Resonance Spectroscopy are non-invasive diagnostic techniques employing magnetic fields without exposure to ionizing radiation. Radiofrequency coils are key components in Magnetic Resonance systems since the use of coils which fit around parts of the body to be imaged is necessary for obtaining high-quality images and spectrums. The purpose of the transmitter coil is to produce a highly homogeneous alternating magnetic field in a wide field of view while the function of the receiver coil is to maximize signal detection while minimizing the noise. For optimizing coils performances for a given application, an accurate design process must be followed. This work reviews methods for coil design and simulation, starting from coil characterization by using its equivalent RLC electric circuit and the use of magnetostatic approach for magnetic field distribution calculation, useful for the design of low frequency coils. For high-frequency tuned coils, the use of numerical methods is very attractive because complex structures such as part of human body can be incorporated in the computational space, permitting the study of the electromagnetic interaction between the coil and the biological phantom. The paper contains an overview of the state-of-art regarding numerical method applications.