Finding the optimal 8-TxRx array for a tight shielded brain coil at 11.7T: a simulation study

Motivation: To fit inside a shielded B0 shimming system and overcome B1+ inhomogeneities, an 8-channel parallel transmit array for human brain studies needs to be developed at 11.7T. Goal(s): Using various metrics, find the optimal 8-Tx array for a 27-cm diameter shielded coil at 11.7T. Meanwhile, consider it for reception supplementing a tighter Rx-array. Approach: Relying on full wave electromagnetic simulations, six different 8-channel arrays types were compared at 500 MHz in terms of B1+ efficiency, homogeneity, sum-of-magnitudes, SAR-constrained kT-points design, and SNR. Results: Accounting for all presented metrics, the full-length dipoles provide the best compromise. Impact: Our parallel arrays benchmarking of the different Tx-Rx types at 11.7T provides new insights for UHF coil development. It confirms previous findings claiming the superiority of dipole-like elements over loops at UHF.