Effects of the load size on the maximum local SAR at 7T

In this study we investigated the effects of the load size on the maximum local SAR at 7T. Specifically, we resorted to: i) 3D full wave numerical electromagnetic simulations for analyzing a surface loop loaded with anatomic human calves models; ii) 2D analytical approach for analyzing a volume resonator loaded with homogeneous cylindrical phantoms having average tissue dielectric properties. In both cases we noticed that the maximum local SAR decreases with decreasing load size: this holds true if the RF magnetic fields (B1+) for the different load sizes are scaled so to achieve the same slice average value of 1ìT.