Optimized Twice-Refocused Adiabatic Spin Echo Sequence for Diffusion Weighted Imaging of Humans at 7T

Priti Balchandani¹, ², Deqiang Qiu²

Diffusion weighted imaging (DWI) at higher field strengths, such as 7 Tesla, may benefit from increased signal-to-noise ratio but suffers from susceptibility to B₁-inhomogeneity. This effect is particularly pronounced when using a twice-refocused spin echo DWI sequence to mitigate eddy current effects. We have employed the adiabatic SLR algorithm for RF pulse design to design optimized B₁-insensitive 180&[deg] RF pulses and used them to replace the standard 180&[deg] pulses in a twice-refocused spin echo DWI sequence. We show improved diffusion weighted images of the human brain at 7T with more uniform SNR when using this method when compared to the standard non-adiabatic approach.