A numerical analysis of radio-frequency power requirements in magnetic resonance imaging experiment

In this paper, a numerical analysis of the radio-frequency (RF) power requirements in magnetic resonance imaging (MRI) is presented at frequencies that span 200-362 MHz. This was performed utilizing an anatomically detailed human head model and a high-frequency RF coil utilized in high-field MRI systems. For axial slices through the brain region, it is demonstrated that the power required in order to obtain an average flip angle across the slice increases with frequency plateauing at a certain value, and then dropping as the frequency increases. The results demonstrate the significance of the electromagnetic interactions between the load and coil and their effects on the so important issue of power-frequency dependence in MRI.