How Safe Are Intrauterine Devices at MRI Procedures with Field Strength Beyond 1.5T?

Jaane Rauschenberg¹, Jens Groebner¹, Wolfhard Semmler¹, Michael Bock¹

The widely used intrauterine contraceptive devices (IUD) had been evaluated for MR-safety only up to field strengths of 1.5T. In this work we performed ASTM measurements of 5 different IUDs at 3T. Additionally, we estimate the potential risk at 7T examinations. The metal-free hormone-containing Mirena IUD has a magnetic retraction thread but it does not produce hazardous heating. For copper-alloy IUDs no magnetic force and no torque could be detected; however, the temperature rise due to RF was up to 3C during 15 min at 3T. For 7T head examinations no potential risk could be detected with the hardware used.