Implants that are often allowed
Hip and knee replacements, spinal rods, and coronary stents placed in recent decades are usually safe in a clinical MRI. They can still distort the picture next to the metal, so the radiologist may not see that exact spot clearly.
What needs a check
- Any implant you cannot name.
- Aneurysm clips from older surgery.
- Shrapnel or metal fragments, especially near the eye.
- Insulin pumps, pain pumps and continuous glucose sensors. Many must be removed.
- Eyelid springs, some IUDs and tissue expanders. Ask; do not guess.
Heating and image quality
Metal can warm slightly and can black out the image around it. That is a limit on the pictures, not automatically a reason to cancel. If the question is about the tissue right next to a replacement joint, the radiologist may suggest a different sequence or a different test.
Always list operations on the safety form, including ones you think are “too old to matter”.