Multi-Frequency Parallel Transmit Fopr Multi-Slice Scan Acceleration

Laura Sacolick¹, Florian Wiesinger¹, Schulte F. Rolf¹, Dong Chen¹, Guido Kudielka¹, Wolfgang Loew¹, Mika W. Vogel¹

The majority of applications thus far for parallel RF transmission in MRI have focused on addressing problems of B1 homogeneity. Here an eight-channel parallel transmit system is demonstrated for a novel application in reducing scan time as well as SAR. The multiple transmit channels are used to produce RF pulses simultaneously at multiple carrier frequencies. These are used to excite and simultaneously acquire four slices, which are then reconstructed by SENSE. The rungs of a body TEM coil assigned to excite each slice are chosen to minimize SAR, and are phase shimmed to maximize B1 field homogeneity. Multi-frequency parallel transmit is used here to give significant scan acceleration that can be combined with multiple receive coil acceleration, and applied in a wide variety of applications.