Safety of intrauterine devices in MRI

Abstract

ObjectivesThe paucity of safety information on intrauterine devices (IUD) for magnetic resonance imaging (MRI) examinations is clinically relevant. The aim of this study is to evaluate the MRI safety of clinically used IUDs composed of copper/gold and stainless steel at 1.5T and 3.0T.Materials and methodsWe assessed and compared the displacement force, torque effects, presence of imaging artifacts and heating of IUDs composed of copper/gold (western IUDs) and stainless steel (China) on 1.5 and 3.0T MRI systems.ResultsGold/Copper IUDs can show small deflection angles of 7° ± 7° in the worst-case field gradient of 40T/m (equivalent to magnetic force of 0.5 mN), while the stainless steel IUD experienced significant magnetic force and deflection (Force > 7.5 N; deflection angle 90° ± 1°). Manual rotation and suspension method show no torque effects on gold/copper IUDs but high torque effects were observed by manual rotation on the stainless steel IUD. Heating measurements showed a temperature increase (rescaled to a wbSAR of 4 W/kg) of 1.4°C at 1.5T / 3.4°C at 3.0 T (stainless steel IUD), 3.2°C at 1.5 T / 3.8°C at 3 T (copper/gold IUD), 3.3°C at 1.5 T / 4.8°C at 3 T (copper 1), 3.8°C at 1.5 T / 4.8°C at 3 T (copper 2). The visible imaging artifacts of the copper and gold IUDs at 3 T MRI reach a diameter of 4 mm ± 1 mm, while the stainless steel IUD resulted in artifacts measuring 200mm ± 10 mm when using gradient echo pulse sequences.ConclusionsStandard IUDs (copper/gold) can be considered as conditional for MR safety at 1.5 T and 3.0 T, demonstrating at wbSAR up to 4W/kg and a magnetic field gradient of up to 40T/m with minimal imaging artifacts. The stainless steel IUD, however, induces unacceptable artifacts and is potentially harmful to patients during MRI due to high magnetic dislocation forces and torque (MR unsafe).

Intrauterine device found in an ovarian tumor

“…Magnetic resonance imaging (MRI) is not routinely used to evaluate IUDs, although modern IUDs are safe for MRI and are mainly made of copper and silver. However, this is not the case for stainless steel ring IUDs, which has been the main type of IUD advocated for by the National Family Planning Program in China since the 1950 s. [ 23 ] Bussmann et al [ 3 ] found that the stainless steel ring not only produced prominent artifacts but also experienced remarkable dislocation on 1.5 and 3.0 T MRI, indicating that these IUDs are unsafe for MR examinations.…”

“…[ 1 , 2 ] In China, IUD insertions are more prevalent, and approximately 44% of women between 15 and 45 years of age use IUDs because of the 1-child policy. [ 3 ] Nevertheless, IUDs are not risk free, and IUD migration is a frequently encountered complication in clinical practice, varying from uterine expulsion to uterine perforation. Partial or complete perforation of the IUD is a rare but serious complication.…”

MRI safety and devices: An update and expert consensus

“…Despite limited studies testing MRI safety of IUDs at 1.5T or 3T, no reports of AEs were found for IUDs made with copper or gold . According to various manufacturers' recommendations, all currently marketed metallic IUDs are MR Conditional up to 3T.…”

“…Notably, the Chinese Ring is a stainless steel IUD ring used in China from 1980–2000 and is considered MR Unsafe at any field strength due to its potential for displacement and rotation. If present, it should be removed prior to MRI . Although the use of this IUD was discontinued in 2000, its 5‐ to 20‐ year lifespan raises the potential that some women may still have the device in situ .…”

Die richtig und die falsch liegende Spirale

“…Die Produktion dieser Verhütungsringe wurde angeblich 1993 eingestellt, vereinzelt gibt es Fallberichte, dass sie bei älteren chinesischen Migrantinnen festgestellt wurden. Im Bereich von 1,5 T bis 3,0 T gibt es für die in Europa hergestellten Spiralen keine Bedenken, magnetisierbarer Edelstahl kann also für IUD auch in Zukunft nicht verwendet werden [4].…”