Inhomogeneous human torso model of magnetohydrodynamic blood flow potentials generated in the MR environment

Magnetohydrodynamic (MHD) voltages resulting from blood flow in a magnetic field contribute to the ECG acquired in the MR environment. These MHD voltages may result in triggering problems for MR image acquisition, since the ECG is typically used for gating. Comsol Multiphysics software was used to model blood flow through the aorta in an inhomogeneous 3D human torso model in a 3.0 Tesla static magnetic field. These voltages were compared with experimentally acquired MHD voltages as well as MHD voltages computed using a simplified torso model. The maximum MHD voltage magnitude was 0.2 mV for the experimental data, 3.04 mV for the simplified model and 0.285 mV for the inhomogeneous torso model. Modeling MHD voltages using an inhomogeneous torso model may aid in optimizing ECG electrode placement for cardiac MRI. In addition, analysis of MHD not only as interference, but also as a physiological signal, may provide blood flow information.