B 1 Effects when Imaging Near Metal Implants at 3 T

Introduction: The MAVRIC and SEMAC techniques enable low susceptibility-artifact imaging near metal implants using conventional spin-echo techniques [1,2]. Previous demonstrations of these techniques have been performed at 1.5T. Extending the techniques to 3T is easily feasible from a susceptibility artifact mitigation standpoint. This is due to the fact that both techniques restrict off-resonance effects to the applied RF bandwidths – which can be kept the same at 1.5T and 3T. However, it has previously been demonstrated that B1 perturbations near metal implants become more prominent at 3T [3]. Here, we further explore this effect on MAVRIC images near a total hip replacement at 3T. Theory: Perturbations to the transmitted B1 magnetic field vary by implant geometries and the wavelength of applied radiation. Here, we consider the case of a metallic rod of length L oriented coaxial with B0. When a homogeneous B1 field of frequency ω is applied to a metallic rod, an electric potential