Effects of magnetic resonance imaging fields on upper eyelid implants

Background. For the therapy of lagophthalmos in facial palsy, gold (99.99%), platinum (99.95%) and platinum/iridium(97%/3%) alloy weights are implanted into the upper eyelid. Investigations on the MRI compatibility of the different eyelid implants with 1.5 and 3.0Tesla-MRT-systems, which are often used for the diagnosis of head and neck tumours, are still missing. Methods. Three different eyelid implants made of pure gold, pure platinum and a platinum/iridium alloy were tested in vitro. As parameters, temperature changes, movements of the implants and picture artefacts of the different implants were determined using a 1.5 and 3.0Tesla MR system. The deflection forces of the implants were evaluated by thread test, lying in a Petri dish and floating in a water bath. Results. No rise in temperature was recorded in any implant. On the water surface, all three implants changed their positions and floated towards the magnetic field. The velocity of the implants increased in the 3.0Tesla system. Increasing the frictional resistance by lying the implants in a Petri dish, there was no movement in the 1.5 or 3.0Tesla systems. In addition, no movement of the implants could be observed in the thread test. All implants made few artefacts, with gold showing the least artefacts. Conclusion. MR imaging at 1.5 or 3.0Tesla may be performed safely for warming up or dislocation of the implant in patients with eyelid implants made of pure gold, pure platinum or a platinum/iridium alloy.