1Research
Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge,
MA, United States; 2Martinos Center for Biomedical Imaging, Dept.
of Radiology, MGH, Charlestown, MA, United States; 3Martinos
Center for Biomedical Imaging, Dept. of Radiology, Massachusetts General
Hospital, Charlestown, MA, United States; 4Dept. of Electrical
Engineering and Computer Science, Massachusetts Institute of Technology,
Cambridge, MA, United States; 5Harvard-MIT Health Sciences and
Technology, Cambridge, MA, United States
We compared the trade-off between local SAR and excitation fidelity for three 7T head transmit array configurations to determine if the approximate orthogonality between the loop coil and dipole element field patterns could be exploited for pTx. Using simulated E and B fields for 8 and 16 element loop arrays and an 8 loop + 8 dipole array, we calculated SAR constrained pTx and RF shimming pulses. Our results show that an array composed of both loop and dipole elements outperforms an array that is composed of loops only in SAR and excitation fidelity.