Because there are many potential risks in the MR environment and reports of adverse incidents involving patients, equipment and personnel, the need for a guidance document on MR safe practices emerged. Initially published in 2002, the ACR MR Safe Practices Guidelines established de facto industry standards for safe and responsible practices in clinical and research MR environments. As the MR industry changes the document is reviewed, modified and updated. The most recent version will reflect these changes. J. Magn. Reson. Imaging 2013;37:501–530. © 2013 Wiley Periodicals, Inc.

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The purpose of this review is to define the current standards addressing safety of medical devices in MRI and to describe ongoing standards development efforts. The American Society for Testing and Materials (ASTM International) began developing standard test methods for determining the MR safety of medical devices in MRI in 1997. To date, five ASTM standards addressing testing and marking medical devices and other items for use in the MR environment have been published. International Standards Organization (ISO) 14630, the general requirements standard for nonactive surgical implants, is currently being revised to include information about MR safety of passive implants and to reference the ASTM standards. To address the unique safety issues of active implants, and in particular, active implants with leads, like pacemakers and neurostimulators, a joint working group between ISO TC150/ SC6 on active implants and International Electrotechnical Commission (IEC) SC 62B MT40 on magnetic resonance equipment for medical diagnosis is working to develop a technical specification for active implantable medical devices (AIMDs) in MRI. While much progress has been made, work still needs to continue to develop a complete body of test methods to allow the evaluation of the safety of medical devices in the MR environment.

Ethylene oxide (EO) gas is commonly used to sterilize medical devices. The amount of residual EO remaining in a device depends partly on the type and size of polymeric material. A major concern is the amount of residue that may be available in the body. With the use of the method described by AAMI for headspace analysis of EO residues, different polymers and medical devices subjected to different numbers of sterilization cycles were examined. Next, the effect of various extraction conditions and extraction solutions on these polymers and medical devices was evaluated. The results showed different polymers desorb EO differently. One polyurethane (PU 75D) had much higher EO residue than a different polyurethane (PU 80A). Repeated extraction of the PU 75D was necessary to quantify total EO residue levels. Different extraction solutions influence the amount and reproducibility of EO detected, whereas multiple resterilizations showed no difference in amount of residual EO. Bioavailability of EO was estimated by extracting the devices and polymers in water. Comparison of total EO residues to EO that was bioavailable showed no difference for some polymers and devices, while others had an almost eightfold difference. Some standard biocompatibility tests were run on extracts and devices, but no significant effects were observed.