16-Channel Parallel Transmission in the Human Brain at 9.4 Tesla: Initial Results

Xiaoping Wu¹, J. Thomas Vaughan¹, Kamil Ugurbil¹, Pierre-Francois Van de Moortele¹

It has been shown that parallel transmission (pTx), which consists of playing different RF pulses through independent transmit (Tx) channels, can be used to mitigate Tx B1 (B1+) nonuniformity and to achieve more homogeneous spatially selective RF excitation at high magnetic field. We have previously reported a successful implementation of Transmit SENSE in the human brain at 9.4 T with an 8 Tx channel system, which required addressing methodological issues such as k-space trajectory inaccuracies and large susceptibility induced δB0. Recently, our 9.4T system has been upgraded with a 16 Tx channel console. Here we report preliminary results of 2D (Transmit SENSE) and 3D (Spoke trajectories) pTx in the human brain at 9.4 T using a 16-channel RF coil.