Common MR Safety IssuesWhat are the most common safety screening scenarios and how do you handle them?
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| MR Safety Issue | Summary Recommendations | Detailed Advice |
|---|---|---|
| General Safety Topics | ||
| Metallic foreign body in orbit | Screen with 2-view orbit x-rays or low-dose CT; do not scan if metal is in contact with globe or in retro-orbital region | Q&A Link |
| Pellets/Bullets | Confirm location and shape by x-ray or CT. If embedded in muscle or bone, generally OK to scan regardless of composition. Many shotgun pellets and military bullets are ferromagnetic, and could pose a danger of movement if located in critical locations (like brain, lung, on near major vessels). Heating is not a concern. | Q&A Link |
| Shrapnel | Confirm location and shape by x-ray or CT. Try to establish material by history. Usually encased by scar and OK to scan, but caution ferromagnetic shrapnel in critical locations (like brain, lung, on near major vessels). Elongated pieces more dangerous. | Q&A Link |
| Pregnancy | Physician should discuss benefits/risks with patient personally; avoid gadolinium if at all possible | Q&A Link |
| Surgical clips/staples/mesh | OK to scan, even immediately after surgery | Q&A Link |
| Tattoos or body piercings | Remove piercing if possible; warn patient about possible heating | Q&A Link |
| Orthopedic hardware (pins, plates, screws, wires, rods, joint replacements) | Generally OK to scan, expect moderate to large metal artifact | Q&A Link |
| Dentures, partial plates, braces | Generally OK to scan if non-magnetic and secure, but remove if possible for head scans to reduce artifact | Q&A Link |
| Contraceptive IUD or diaphragm | Generally OK to scan | Q&A Link |
| Medication patch | Metal-backed patches may cause burns and should be removed | Q&A Link |
| Insulin pump | All are MR Unsafe, must be removed | Q&A Link |
| Artificial or prosthetic limb | All are MR Unsafe, must be removed | Q&A Link |
| Hearing aid | All are MR Unsafe, must be removed | Q&A Link |
| Watches, rings, jewelry, glasses, hairpins | Remove; why take a chance? | Q&A Link |
| Implanted drug infusion pump | Some are MR Conditional, others MR Unsafe | Q&A Link |
| Street clothing and underwear | Remove and provide hospital gown; reduces chances of small objects like hairpins or paperclips being brought into scanner; also some clothing materials contain metal fibers that may cause burns | Q&A Link |
| Neurologic/Head and Neck Safety Topics | ||
| Aneurysm clip | Nearly all implanted in last 20 years are non-ferromagnetic and OK to scan, but still wise to confirm model; older clips need very careful identification | Q&A Link |
| Cerebrospinal shunts and drains | Nearly all are OK to scan; programmable shunt pressures must be checked after scanning | Q&A Link |
| Intracranial bolts/pressure monitors | Most are MR Conditional | Q&A Link |
| Epidural catheters | Most are MR Unsafe due to wire reinforcement or imaging only with a transmit-receive head coil | Q&A Link |
| Neurostimulators (brain, spinal cord, peripheral nerve) | Many newer models are MR Conditional; older units MR Unsafe | Q&A Link |
| Cochlear and other ear implants | Some newer models are MR Conditional, others MR Unsafe | Q&A Link |
| Thoracic and Cardiovascular Safety Topics | ||
| Vascular stents, filters, and coils | OK to scan immediately after implantation | Q&A Link |
| Cardiac valves & annuloplasty devices | OK to scan immediately after implantation | Q&A Link |
| Cardiac pacemaker or defibrillator | Newer models can be scanned under specific conditions only; many older (non-conditional) models may also be scanned under even more restrictive protocols | Q&A Link |
| Temporary Transvenous Pacemaker | MR Unsafe, must be removed | Q&A Link |
| Retained epicardial pacing wires | Broken off wires OK to scan | Q&A Link |
| Vascular access port | Nearly all are non-ferromagnetic and OK to scan immediately after implantation | Q&A Link |
| Abandoned vascular lead | Probably should consider as MR unsafe, but some controversy depending on clinical scenario | Q&A Link |
| Loop recorder | Most common types are MR Conditional; download data before scanning | Q&A Link |
| Tissue expander (e.g. breast) | Nearly all have magnetic ports and are MR Unsafe | Q&A Link |
| Abdomen and Musculoskeletal Safety Topics | ||
| Penile implants | OK to scan | Q&A Link |
| PillCams | Avoid scanning while in GI tract, but doubtful harm if you do | Q&A Link |
| Foley catheters | OK to scan, but special attention to those with temperature probes that are MR Conditional | Q&A Link |
| Halo and external fixation devices | OK but must be sure they are rated as MR-compatible | Q&A Link |
| Bone fusion stimulators | MR Conditional | Q&A Link |
| Gastric pacemakers | MR Unsafe | Q&A Link |
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References
Shellock FG. MRISafety.com (the definitive site for all things safety)
Shellock FG. MRISafety.com (the definitive site for all things safety)
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