Investigation of 7T 16-channel dual-row transmit array coils: A case study of static RF shimming

We evaluated and compared the performances of two simulated radiofrequency (RF) dual-row transmit array coils for magnetic resonance imaging (MRI), using a range of static RF shimming settings. The arrays were non-overlapped and overlapped. A simple strategy was explored for greatly improving the uniformity of the RF field within the head. Reducing the coupling between coil rows was found to increase the destructive interference between the transmitted fields from each of the rows, which beneficially suppresses the large magnetic field maximum at the center of the head. The optimal phase difference between the RF excitations applied to each row depends on the desired volume of interest for MRI examinations.