Near-field homogeneity optimization for several MRI dual-row RF head array geometries at 300 MHz

We used the interior-point optimization algorithm to perform static RF shimming of three overlapped dual-row magnetic resonance imaging (MRI) arrays. These had radiative elements of axial lengths 80, 100, and 110 mm respectively. We evaluated the robustness of the static shims thus obtained. The head-and-torso model was located at different axial positions, including one where the distance between the crown of the head and the array´s axial centre was about 50 mm. In this head position, with radiative elements of axial length 110 mm, the inhomogeneity, calculated over a brain volume with and without the cerebellum, could be reduced to as little as 5.4 % and 8.9 % respectively.