MRI interactions with medical devices

Given the particular environment created by a magnetic resonance imaging (MRI) scanner, various kinds of interaction can occur with other medical devices, depending on the nature of the device, active or passive, on the materials. Generally speaking, manufacturers of medical devices must analyse and indicate any potential risk related to reasonably foreseeable environmental conditions such as magnetic fields and to other medical treatments such as MRI. Thus, information about the compatibility of a medical device with MRI should be available on the device user manual. According to the latest international standard (ASTM 2503), a medical device can be magnetic resonance (MR) Safe, MR Conditional, and MR Unsafe. MR Safe poses no known hazards in all MRI environments; MR Conditional has been demonstrated to pose no known hazards in a specified MRI environment with specified conditions of use; MR Unsafe is known to pose hazards in all MRI environments. Implanted medical devices are those raising major concerns in MR environments. Each implanted device must be clearly identified, and it is important to screen each patient before MRI examination. The prevalence of patients with various kinds of implants is increasing. For these devices, it could be important to refer not only to the user manual, but also to the scientific literature. Indeed, it could happen that it is necessary to perform an MRI examination which does not completely respect the MRI conditions indicated by the device manufacturer. In these cases, the clinical or in vitro experiences reported in the scientific literature could help in yielding elements to support the medical decision.