Can a medical device be used safely around magnetic resonance imaging equipment? It's not always easy for healthcare providers or patients to know. Now a new final guidance document issued by the US Food and Drug Administration (FDA) recommends that medical device manufacturers test and label their products to ensure that use of their devices doesn't lead to injuries.
The guidance, Establishing Safety and Compatibility of Passive Implants in the Magnetic Resonance (MR) Environment, specifically applies to passive implanted medical devices. Unlike active implanted devices, which require power to operate, passive implants tend to support the structure of the body and do not require power to operate.
While their lack of electrical components can make them safer, FDA's guidance notes that MRIs can still have an effect on these devices, causing them to become displaced or heated by radio frequencies. "Patients have been severely burned during an MR scan," FDA notes in the guidance.
The implants can also obscure the image produced by the MRI, potentially leading to either an inaccurate diagnosis or leading to "inappropriate medical action."
Testing and Labeling Recommendations
What is a manufacturer of one of these devices to do, then?
FDA recommends that all passive implants be labeled with specific safety information regarding their use within the magnetic resonance environment.
"Testing should encompass the range of sizes of the device you intend to market," FDA explains in the guidance, and testing should anticipate "the worst-case scenario for each test." Regulators said they are particularly interested in seeing data about magnetically induced torque, displacement force and heating of tissue around the device.
Findings should ultimately support a label of "MR Safe," MR Conditional" or "MR Unsafe," FDA said. An "MR Conditional" finding should be accompanied on the label of the device with the conditions under which it can be used safely in an MR environment.
All devices, including those which "have historically not provided any information about MRI safety," should contain a statement that the device "has not been evaluated for safety and compatibility in the MR environment."
Establishing Safety and Compatibility of Passive Implants in the Magnetic Resonance (MR) Environment