Reconstruction of current density distributions in axially symmetric cylindrical sections using one component of magnetic flux density: computer simulation study

In magnetic resonance current density imaging (MRCDI), we inject current into a subject through surface electrodes and measure the induced magnetic flux density B inside the subject using an MRI scanner. Once we have obtained all three components of B, we can reconstruct the internal current density distribution J = del x B/mu(0). This technique, however, requires subject rotation since the MRI scanner can measure only one component of B that is parallel to the direction of its main magnetic field. In this paper, under the assumption that the out-of-plane current density J(z) is negligible in an imaging slice belonging to the xy-plane, we developed an imaging technique of current density distributions using only B-z, the z-component of B. The technique described in this paper does not require a subject rotation but the quality of reconstructed images depends on the amount of out-of-plane current density J(z). From numerical simulations, we found that the new algorithm could be applied to subjects such as human limbs using longitudinal electrodes.