A comparison of various custom-built pTx RF arrays for body imaging at 7T with regard to their transmit efficiency

Motivation: A standardized pTx body array would be highly beneficial for 7T, especially as a step toward achieving an extension of the existing 7T CE label/FDA clearance to whole-body MRI. Goal(s): To compare the transmit performance (Tx efficiency/coverage) of 5 different existing body coils containing different element types. Approach: Measure relative and absolute B1+ maps and evaluate them regarding the Tx efficiency and Tx heat-foot coverage. Results: The B1+ efficiency was similar for all local coil concepts with some differences in heat-foot excitation coverage. The remote array achieved the largest heat-foot excitation coverage and can achieve similarly high flip angles as the local arrays. Impact: B1+ efficiency was similar for all local coil concepts with some differences in excitation coverage. The remote array achieved the largest excitation coverage and can achieve similarly high flip angles as the local arrays if sufficient transmit power is available.