A novel design methodology accounting for ramping and field inhomogeneities in dreMR imaging
Abstract
Delta relaxation enhanced magnetic resonance (dreMR) is a field cycled magnetic resonance imaging method for quantitative molecular imaging. DreMR uses an insertable field cycling coil to exploit longitudinal dispersion of contrast agents producing signal proportional to their concentration. Assumptions in the development of dreMR included instantaneous ramping of the insert coil and perfectly homogeneous field shifts. Here we discard these assumptions and show that finite ramping and field inhomogeneities can impair proportionality to agent concentration and produce significant signal from background tissues. To mitigate these effects, a novel dreMR coil design method is developed employing a boundary element method designed layer to the system which corrects field inhomogeneities, maximizing the usable dreMR imaging region. While a dreMR coil has not yet been constructed for use on humans, with these improvements it is expected that human designs will be much more feasible allowing the extension of this method to clinical studies.