What implants are not safe for MRI?

For an individual with certain implants, Magnetic Resonance Imaging (MRI) can pose significant risks due to the powerful magnetic fields and radiofrequency waves involved. It is critical to always inform your healthcare provider and MRI technologist about any and all implants you may have before undergoing an MRI scan.

Implants Requiring MRI Precautions

The strong magnetic fields used in MRI can interact with metallic objects and electronic devices in the body, potentially causing them to heat up, move, or malfunction. Therefore, several types of implants are considered unsafe for MRI or require specific safety protocols and expert evaluation before a scan can proceed.

Key Implants That May Not Be MRI Safe

The following implants require immediate notification to your technologist before entering an MRI suite due to potential safety concerns:

• Cochlear Implants and Hearing Aids: These devices contain magnetic components that can be damaged or displaced by the MRI's strong magnetic field. The interaction can also cause significant heating, potentially leading to tissue damage or hearing loss.
• Brain Aneurysm Clips: Certain types of older aneurysm clips are ferromagnetic, meaning they can be attracted and moved by the MRI magnet. This movement could potentially lead to a hemorrhage or other severe neurological damage. Modern clips are often made of non-ferromagnetic materials and may be MRI-safe, but verification is always necessary.
• Metal Coils/Stents Placed Inside Blood Vessels: While many newer stents and coils are designed to be MRI-conditional or safe, older versions or certain types may pose risks of heating or displacement within the blood vessels.
• Neurostimulators or Implanted Programmable Devices: Devices such as spinal cord stimulators, deep brain stimulators, and vagus nerve stimulators contain electronic components that can be damaged or malfunction when exposed to MRI fields. There is also a risk of heating at the lead tips, which could injure surrounding tissue.
• Cardiac Defibrillators and Pacemakers: These life-sustaining devices are particularly sensitive to MRI. The magnetic fields can interfere with their programming, cause rapid or irregular pacing, heat the leads, or even permanently damage the device, leading to life-threatening situations. Some newer models are "MRI conditional" and can be scanned under very specific conditions, usually requiring reprogramming before and after the scan by a cardiology team.

Why These Implants Pose a Risk During MRI

MRI utilizes a powerful magnet and radiofrequency (RF) energy to create detailed images of the body. When metallic or electronic implants are present, several risks arise:

• Heating: The RF energy can cause metallic implants, particularly wires or leads, to heat up significantly, potentially leading to burns or tissue damage.
• Movement/Displacement: Ferromagnetic implants can be pulled or rotated by the strong magnetic field, leading to severe injury or device displacement.
• Malfunction: Electronic devices can be damaged, reprogrammed, or cease to function correctly due to the magnetic and RF fields, potentially compromising patient safety or rendering the device inoperable.

Always Inform Your MRI Technologist

Due to these potential risks, it is paramount to undergo a thorough screening process before any MRI examination. Always inform your referring physician and the MRI technologist about any implant or metal in your body, no matter how insignificant it may seem. They will assess the specific type of implant, its MRI safety status (MRI safe, MRI conditional, or MRI unsafe), and determine if the scan can be performed safely.

For more detailed information on MRI safety, you can consult resources like RadiologyInfo.org.

Summary of Implants Requiring MRI Caution