Metallic implants used in bone and joint arthroplasty induce severe spatial perturbations to the B0 magnetic field used for high-field clinical magnetic resonance. These perturbations distort slice-selection and frequency encoding processes applied in conventional two-dimensional MRI techniques and hinder the diagnosis of complications from arthroplasty. Here, a method is presented whereby multiple three-dimensional fast-spin-echo images are collected using discrete offsets in RF transmission and reception frequency. It is demonstrated that this multi acquisition variable-resonance image combination technique can be used to generate a composite image that is devoid of slice-plane distortion and possesses greatly reduced distortions in the readout direction, even in the immediate vicinity of metallic implants.
Copyright 2009 Wiley-Liss, Inc.