Metallic Artifacts on MR Imaging and Methods for Their Reduction

摘要

Metallic artifacts on MR imaging are typically induced by differences in magnetic susceptibilitybetween the metallic implant and surrounding tissue. Conventional techniques for metal artifactreduction require MR machines with low field strength, shift in the frequency-encodingand phase-encoding directions according to the axis of metallic implant, increased receiverbandwidth and matrix, decreased slice thickness, and utilization of the short tau inversion recoveryor Dixon method for fat-suppression. Slice-encoding for metal artifact correction andmulti-acquisition variable-resonance image combination can dramatically reduce the numberof metallic artifacts. However, these sequences have a considerably long acquisition time. Furthermore,the recently developed acceleration techniques including compressed sensing cansolve this problem.