MRI Safety with Metal Hip Replacements
Yes, metal hip replacements are safe to scan with MRI, and MRI with metal artifact reduction sequences (MARS-MRI) is actually the preferred advanced imaging modality for evaluating complications around hip prostheses. 1
Key Safety Points
MRI does not pose a safety hazard to patients with modern hip prostheses—the implants are firmly fixed and will not move or heat dangerously in the magnetic field 1
Metal artifact reduction sequences (MARS-MRI) are specifically designed to enable soft tissue assessment around metallic hip prostheses, including evaluation of the pseudocapsule, tendons, and neurovascular structures 1
The American College of Radiology explicitly supports MRI use for hip prosthesis evaluation, particularly noting that MARS-MRI enables assessment of soft tissues that would otherwise be obscured by metal artifacts 1
Clinical Applications Where MRI is Recommended
Metal-on-Metal (MoM) Hip Prostheses
MARS-MRI is the first-line imaging modality for detecting adverse reactions to metal debris (ARMD) in symptomatic patients with MoM implants 1
This recommendation exists because radiographs may be completely normal in patients with symptomatic pseudotumors, making MRI essential for diagnosis 1
MRI has 95.4% sensitivity for detecting osteolytic lesions around hip prostheses, significantly higher than CT (74.7%) or radiographs (33.3-51.5%) 2
Technical Considerations
MAVRIC-SL sequences at 3 Tesla MRI significantly reduce metal artifacts compared to conventional fast spin echo sequences, though with some trade-off in spatial resolution 3
The reduction in artifact size substantially improves visualization of joint anatomy and diagnostic confidence for implant-associated abnormalities 3
Both 1.5T and 3T MRI systems can be used effectively with appropriate metal artifact reduction techniques 4, 3
Common Pitfall to Avoid
Do not assume MRI is contraindicated simply because a patient has a metal hip replacement. This outdated concern prevents patients from receiving optimal diagnostic imaging. Modern orthopedic implants are MRI-conditional or MRI-safe, and the benefits of soft tissue visualization far outweigh any imaging limitations from metal artifact 1, 4
When MRI is Particularly Valuable
Detecting pseudotumors and soft tissue masses that are invisible on radiographs 1, 4
Evaluating adverse local tissue reactions (ALTR) including synovitis, effusions, and bursal collections 1
Assessing abductor tendon abnormalities and peritendinous edema in patients with lateral hip pain 1
Monitoring disease progression in patients with known metal-on-metal complications 5, 6