MRI Safety with Cardiac Stents
Patients with coronary artery stents can safely undergo MRI at any time after stent placement without delay, as modern coronary stents are made of non-ferromagnetic materials that are not significantly affected by MRI magnetic fields. 1
Safety of MRI with Coronary Stents
Current Evidence
- Modern coronary stents are MRI-compatible and can be safely imaged immediately after implantation 1
- Previous recommendations to delay MRI for 4-6 weeks after stent placement are outdated 1
- Multiple studies have confirmed the safety of MRI in patients with coronary stents:
- A study of 111 patients who underwent MRI within 8 weeks of stent placement (median 18 days) showed no stent thrombosis events 2
- Another study of 49 patients who underwent MRI at a median of 1 day after complex percutaneous coronary intervention (including drug-eluting stents) reported no acute thrombosis 3
- Temperature and motion studies of 14 different coronary stents showed no significant heating or movement during MRI scanning 4
Important Considerations
- Patients should remain on their prescribed dual antiplatelet therapy (DAPT) when undergoing MRI 1
- For bare-metal stents, aspirin should be continued indefinitely, and a thienopyridine (such as clopidogrel) is typically needed for at least 4 weeks 1
- For drug-eluting stents, DAPT is generally recommended for at least 12 months 1
Potential Limitations and Special Cases
Visualization Challenges
- Metal in the chest from sternal wires or coronary stents may preclude visualization of coronary arteries near the metal during MRI 5
- The coronary lumen is generally not well observed in the region of a coronary stent during imaging studies 5
- If visualization of the interior of the stent is needed, CT or invasive angiography may be preferred 5
Patient Considerations
- Patients with implanted electronic devices such as internal defibrillators are generally excluded from receiving MR imaging 5
- Claustrophobia occurs in 1-5% of patients who undergo MR imaging and may require anxiolytics 5
Clinical Algorithm for MRI in Patients with Coronary Stents
- Confirm stent type: Verify that the patient has a modern coronary stent (virtually all stents placed in the last two decades are MRI-compatible)
- Maintain antiplatelet therapy: Ensure patient continues prescribed DAPT during MRI
- Proceed with MRI: No waiting period is necessary after stent placement
- Consider alternative imaging: If visualization of the stent lumen is specifically needed, consider CT angiography or invasive angiography instead
The American College of Cardiology clearly states that patients with coronary stents can undergo MRI examination at any time after implantation, with no need to delay imaging 1. This recommendation is supported by multiple clinical studies demonstrating the safety of MRI in patients with recently placed coronary stents 6, 3, 2.