Eddy current compensation using screened gradients

In magnetic resonance imaging using superconducting magnet eddy currents are induced in the magnet dewars during the switching of magnetic field gradients. This leads to a loss of amplitude and linearity in the resulting gradients. Three methods of compensation are available, namely to work with the gradient set as far as possible from the magnet dewars, to use software or hardware to apply pre-emphasis and finally to use active screened gradient sets. None of these techniques give perfect compensation, but clearly combinations can be used to obtain optimum performance