A 3D model of magnetohydrodynamic voltages: Comparison with voltages observed on the surface ECG during cardiac MRI

The magnetohydrodynamic (MHD) effect generates voltages which distort the ECG obtained during cardiac MRI. Consequently, MHD voltages result in triggering problems for MR image acquisition. In addition, since the MHD effect is related to blood flow, analysis of it not only as interference, but also as a signal may provide useful blood flow information. Comsol Multiphysics modeling software was used to compute and model the MHD voltages in 3D. These voltages were compared with MHD voltages obtained experimentally from the subtraction of ECGs taken outside the MRI magnet from ECGs taken inside the magnet. The maximum MHD voltage magnitude for the experimental data was 0.2 mV and was 3.04 mV for the modeled data when calculated on the surface of the uniform volume conductor. By modeling MHD voltages in 3D, we can learn about their effect on the ECG during cardiac MRI.