B1 Mapping of an 8-Channel TX-Array Over a Human-Head-Like Volume in Less Than 2 Minutes: The XEP Sequence

Alexis Amadon¹, Nicolas Boulant¹, Martijn Anton Cloos¹, Eric Giacomini¹, Christopher John Wiggins¹, Michel Luong², Guillaume Ferrand², Hans-Peter Fautz³

Efficient mitigation of the RF inhomogeneity using transmit coil arrays relies on the knowledge of the individual B1-maps. As the number of transmit channels increases, so does the acquisition time of all maps. Here we focus on a fast 2D sequence proposed by Fautz et al. which we adapt for multi-slice B1-mapping. We compare its results with that of the 3D AFI sequence on a spherical phantom surrounded by 8 transmit elements at 7T. We show comparable performance with a 12-fold increase in speed, making accurate B1-mapping of the human head feasible in 1.5 minutes for 8 transmit channels.