MRI Safety in Patients with ERCP Metallic Stents
Yes, MRI can be safely performed in patients with ERCP metallic biliary stents at field strengths of 1.5 Tesla or less, and likely at 3 Tesla as well.
Evidence for MRI Safety with Metallic Stents
The safety profile of metallic stents in MRI environments has been well-established through direct testing:
Biliary metallic stents show no magnetic field interactions, minimal heating (≤0.3°C temperature change), and only localized artifacts that do not create diagnostic problems as long as the area of interest is not positioned exactly where the stent is located 1
Testing at 1.5 Tesla demonstrated that 10 different types of metallic stents exhibited no translational attraction or torque, confirming they would not migrate during MRI procedures 1
Even at 3 Tesla field strength, metallic stents (including cobalt alloy-based stents) show only minor magnetic field interactions insufficient to cause migration, with heating limited to +0.5°C 2
Timing Considerations
MRI can be performed immediately after stent placement without waiting periods 2. This is particularly important because:
The relative lack of magnetic field interactions means there is no need to wait for tissue ingrowth or stent endothelialization before performing MRI 2
Long-term safety data from coronary stent studies (which face higher mechanical stress than biliary stents) confirm that MRI performed 1-7 days after bare-metal stent implantation carries no increased risk of adverse events 3
Artifact Considerations
While MRI is safe, clinicians should be aware of imaging limitations:
Artifacts create signal voids extending approximately 16 mm for T1-weighted spin-echo sequences and 23 mm for gradient-echo sequences around the stent 2
These artifacts are clinically insignificant unless the specific anatomic area of diagnostic interest is immediately adjacent to or overlapping with the stent location 1, 2
For biliary stent evaluation itself, alternative imaging modalities (ultrasound, CT, MRCP) remain more appropriate 4
Clinical Context
This safety profile applies regardless of whether the ERCP stent is:
- Plastic or metallic (uncovered metal stents are preferred in unresectable disease) 4
- Temporary or permanent 4
- Recently placed or long-standing 3
The presence of an ERCP metallic stent should not be considered a contraindication to medically necessary MRI examinations 1, 5.