Investigation of Magnetic Field Gradient Waveforms in the Presence of a Metallic Vessel in Magnetic Resonance Imaging Through Simulation

Abstract

We have previously established the ability to characterize eddy currents and their impact on the magnetic fields in metal vessel magnetic resonance imaging applications through comparison with measured data. We now use simulation to investigate the spatiotemporal characteristics of eddy currents and their magnetic fields encountered in metal vessel magnetic resonance imaging that may not easily be experimentally verified. Simulations using CST EM Studio have revealed the impact of an offset in the positioning of the metal vessel in a superconducting magnet bore as well as the consequences of the different amplitude magnetic gradients employed during imaging experiments. Furthermore, we investigate the response of the metal vessel to magnetic field gradients generated from nonplanar and planar gradient coil geometries (encountered in superconducting and permanent magnet-based systems). Establishing the basic electromagnetic properties of the metal vessel in a magnetic resonance sense through simulation permits us to replace our simple metal vessel with a more sophisticated rock core holder design and investigate its properties.