Effects of metallic implants on magnetic resonance images

Medical images which are generated by Magnetic Resonance Imaging device that have been widely used for clinical purposes and academic researches provides detailed anatomical information about examined tissue. However, metallic implants used in human body effects quality of the images. Influence amount of these materials depends on the magnetic properties of the metals used in implant production. Materials which have high magnetic dipole moment emit high energy when in magnetic field. Energy obtained from biological tissue during MR image generation may interfere with the emitted energy from the magnetic metallic implant, resulting in the information loss of the tissue. Image quality is degraded depending on material type in this case.In this study, it is analysed that how metallic implant samples with different geometries and contents effect on MR images. Three different geometries were produced to investigate the effect of the shape of implants on MR images. Implant samples used in the analysis were manufactured using 316LVM, 316L, CoCrMo and Ti-alloy materials which are commonly used in orthopaedics.Obtained MR images were analysed using image processing techniques. It has been found that 316LVM implants cause much more deterioration in MR images than Ti alloy implants. This is due to the ferromagnetic elements used in implant production. It is also observed that the thick samples lead to further deterioration than the thin specimens. As the amounts of magnetic material contain increases, the effect of distortions of images is also increase.Keywords: Biometals, Implant safety, MRI, Image artefacts