A method for NMR imaging of a magnetic field generated by electric current

This paper proposes a method to detect electric currents using nuclear magnetic resonance (NMR) imaging. The motion of magnetization during applications of electric current and radio-frequency (RF) pulses was formulated based on the rotating-frame Bloch equation. The relationship between a magnetic field generated by electric current and the signal intensity of an NMR image was calculated for a Gaussian RF pulse with a duration of 10 ms. Images of a phantom were obtained with and without application of electric current to a straight wire. The magnetic field generated by the electric current caused a decrease in the signal intensity around the wire. The magnetic field measured from the images was in good agreement with the theoretically calculated magnetic field. In the case of an RF pulse duration of 10 ms, a maximum sensitivity of 3.0×10⁵ T^-1 was obtained at a magnetic field intensity of 2.7×10^-6 T.