Simultaneous multi-slice excitation by parallel transmission using a dual-row pTX head array

Introduction Simultaneous multi-slice (SMS) imaging with receiver arrays allows for greatly accelerated 2D single-shot acquisitions with BOLD or diffusionweighted EPI (1-4), and spirals (5). The commonly used SMS excitation methods require specially designed multi-band (MB) (1,2) or PINS RF pulses (6) to excite N slices. In this abstract we explore the use of parallel transmission (pTX) for SMS excitation, which can be achieved by uniquely frequency shifted slice-select pulses on subsets of pTX elements that are closets to the slices they excite. pTX has been shown to be useful for managing B1 + and B0 homogeneity and SAR. Using a dual-ring 3D pTX coil design (7) and blipped-CAIPIRINHA EPI, we show that factor-2 SMS excitation with parallel transmission (pTX) can readily be achieved with conventional single-band RF pulses. Factor-4 SMS using dual-band RF pulses applied to each ring are also shown. For pTX coils with inherent TX-sensitivity encoding along the slice direction, the approach can reduce total required RF power (global SAR) compared to MB pulses with N frequency bands used on all coil elements as well as accelerating SMS multi-dimensional excitations.