Figure 1.

The proposed pulse sequence to map conductivity using eddy currents generated by an adjustable large crusher gradient. This gradient is positioned immediately before the excitation RF pulse with a flip angle of α. Eddy currents are generated during the rise and descent of the EC crusher. Using a 7T animal scanner, δ was 40 μs and reached a peak amplitude of 200 mT/m, giving a slew rate of 5000 T/m·s; Δ was 5 ms and τ was 100 μs. The intent is that the eddy currents created by the pulse rise will have decayed when the pulse decay occurs. If the eddy currents from the pulse decay last beyond the time period τ they will affect the MRI signal.