MR current density and conductivity imaging: the state of the art.

Current density imaging (CDI) is an imaging technique that measures electrical current density distributions in a volume of material or tissue, which can be imaged using magnetic resonance imaging (MRI). Measurements of current density are obtained by applying an external current to the material/tissue during an MRI acquisition. The magnetic fields produced by the applied current are mapped onto the phase image of the MRI acquisition. The phase images are processed to compute the current density distribution. Performing CDI requires an MRI system, additional hardware, a modified pulse sequence (PSD) and data processing software. Greig C. Scott, Michael L.G. Joy and R. Mark Henkelman developed CDI in 1988 at the University of Toronto (Canada). The CDI Research Group is presently based at the University of Toronto and is supervised by the author. This paper describes the CDI technique, its applications by this and other groups and recently proposed methods for electrical conductivity imaging based on the technique.