The Effects of Magnetic Resonance Imaging on Breast Tissue Expanders

Abstract

The Tissue Expander (TE) for breast reconstruction covered by insurance in Japan is the Allergan Natrell^® 133 series. This device has a filling port consisting of a small magnet which allows the surgeon to identify the site for the saline injection. MRI scans are strictly prohibited because the magnetic field can interfere with the TE, resulting in potential hazards. We investigated the influence of MRI in two ways : MRI attraction test and case report. Methods : 1. MRI attraction test : We brought the Allergan Natrell^® 133 TE (MV-12) into a 3T MRI system and investigated the influence of the MRI (magnetic field interaction, heating) . 2. Case report : A 54-year-old woman who underwent TE insertion was given an MRI scan accidentally. We reviewed the situation and studied the TE that had been removed from the body. Results : 1. MRI attraction test : The attraction force functioned from a distance of 50 cm, and the TE was attracted in the same direction. Its attractive power was not strong and even a female experimenter could hold the TE in place ; the rise in temperature was very slight. 2. Case report : The patient did not realize any symptoms or exhibit physical changes during the MRI scan. There was no apparent damage or corruption on the removed TE. Conclusions : MRI scans do not seem to cause serious complications such as tearing through the body or severe burns. However, as the TE has ferromagnetism, we should disseminate the risk of MRI to medical institutions.