Imaging electrical current density using 0.15 T magnetic resonance imaging system

Abstract

Imaging of electrical current density in conducting objects, which contain nuclear magnetic resonance (NMR) active nuclei, is planned using a 0.15 T magnetic resonance imaging (MRI) system. The current to be imaged is externally applied to the object in synchrony with a standard spin-echo pulse sequence. Applied current is a bipolar DC current pulse, which creates a DC current density at each cycle within the object. The applied current pulse creates a measurable magnetic flux density. The component of magnetic flux density parallel to the main magnetic field accumulates an additional phase in the phase of the complex MR image. Magnetic flux density can be extracted using two phase images acquired with and without the current pulse. Measurement of all three components of magnetic flux density makes the reconstruction of current density possible with a spatial resolution equal to the half of the MR resolution. Experiments performed on several phantoms and the results are presented.