Numerical Study of the Optimal Geometry of MRI Surface Coils

An image based method to compute the signal to noise ratio and specific energy absorption rate of MRI surface resonator coil for different polygonal geometries is proposed. A commercial software tool based on the Finite Element Method was used to numerically solve the Maxwell´s equations to form bidimensional images of the electric and magnetic fields. These images represent the point by point fields inside the surface coil. With this data, MATLAB specifically written programs were used to numerically compute the signal to noise ratio and the specific absorption rate for different surface coil geometries. Bidimensional images and contours of the signal to noise ratio and specific absorption rate were also computed and compared. Uniformity profiles of various geometries were calculated using the resulting data to determine the optimal field uniformity. According to the signal to noise ratio images, the squared shaped coil shows the most suitable uniformity for magnetic resonance imaging applications. This can be a good candidate for phased array imaging and parallel imaging.