A numerical technique, based on the combination of a finite element method and a boundary integral method, has been developed to compute the induced signal in MRI antennas. This signal rises from a free movement of precession of the transverse magnetization of the sample to explore. In our modeling, the transverse magnetization represents the magnetic source field. Its flux embraces the antenna to give rise to a sinusoidal current which is very quickly attenuated in time (a few ms); it represents the signal containing all the information of the sample. We here want to find the geometrical and electromagnetic characteristics of the antennas which permit to have a signal to noise ratio as great as possible. In our computation, we have taken into account leading factors such as the distance between the probe and the organ to be explored and also the geometrical and electromagnetic characteristics of the probe. Our modeling of printed circuits MRI antenna has been validated by comparing with experimental measurements and also with an anlytical method. We have developped it by taking into account their geometries and their electromagnetical characteristics in order to have a better signal/noise ratio. We have considered principal factors such as the distance between the antenna and the organ to explore and also the electromagnetic characteristics of the antenna.
Numerical modeling of antennas of MRI signal image acquisition during relaxation