Simultaneous B1+ Magnitude and Phase Mapping Using Multi-Echo AFI

Narae Choi¹, Joonsung Lee¹, Dong-Hyun Kim¹

The measurement of the transmitted radiofrequency (RF) field is useful for many MR applications. Conventionally, the amplitude of the B1 was measured by B1 mapping methods and the phase of the active magnetic RF field component H+ was estimated by using spin echo (SE) sequence. Using SE sequence has one drawback which is long scan time due to relatively long TR compared to GRE sequence. This study focuses on the estimation of B1 magnitude and phase simultaneously using much faster acquisition, double TR multi-echo gradient echo sequence. This approach is validated in phantom and in-vivo experiments.