Magnetic resonance imaging contraindications

David Goldemund M.D.
Updated on 12/02/2024, published on 23/05/2022

  • MRI has gradually become one of the most important non-invasive imaging techniques in neurology
  • it is a safe and effective imaging modality for most patients when used appropriately
  • it uses a strong magnetic field, changing magnetic fields, radio waves, and a computer to acquire detailed images
  • healthcare professionals need to be aware of the potential risks and contraindications associated with MRI
  • four main potential hazard sources exist:
    • static magnetic field (most commonly 1.5 or 3T) attracts ferromagnetic objects and accelerates them toward the center of the device – can dislodge implants or affect the functioning of devices such as pacemakers and pumps
    • radiofrequency (RF) fields and variable gradient magnetic fields – can induce tissue heating, especially in the presence of implants (both ferromagnetic and non-ferromagnetic). These fields are a source of loud noise; hence, the use of hearing protection (headphones or earplugs) is essential throughout the examination
    • gadolinium contrast agents (GBCA) can trigger nephrogenic systemic fibrosis (NSF)

Metallic devices and objects

  • all implanted devices require investigation through a certified MRI safety website or the individual manufacturers’ website. If there is no evidence or information about the MRI safety of a device/implant, it must be considered MRI unsafe
  • it is the referring physician’s responsibility to obtain appropriate information about the implant! In cases of relative contraindication, the referring physician must weigh the benefits of the examination and inform the patient of the risks (after consulting with a radiologist)
  • all removable metal prostheses (dental bridges) and electronic devices (e.g., hearing aids) must be removed before entering the MRI room
  • dental implants are usually composed of titanium or zirconium and are deemed safe
  • three principal issues may arise with metal implants during MRI:
    • artifacts
    • the risk of implant migration
    • the risk of implant heating leading to adjacent tissue burn
Absolute contraindications
  • MRI non-approved cardiac implantable electronic devices (CIED)  → see more here
    • pacemaker (PM), cardioverter-defibrillator (ICD), cardiac resynchronization therapy (CRT) device
    • these devices can malfunction or cause harm if exposed to the strong magnetic field of an MRI scanner, potentially leading to cardiac arrhythmias or even death
  • temporary external transvenous pacing leads and abandoned intracardiac pacing leads
    • radiofrequency pulses can induce currents that may cause thermal injuries
  • implantable neurostimulation systems with unknown MR compatibility
  • cochlear implants, unless MR compatibility is documented
    • several implants have already received conditional status for MRI
    • use a 1.5T scanner only
    • pre-MRI CT of the temporal bone is required for assessing bone thickness
  • drug infusion pumps (insulin delivery, analgesic drugs, or chemotherapy pumps)
    • external pumps must be removed and kept out of the MRI environment
    • implanted pumps may be compatible with MRI; the manufacturer’s guidelines for the specific pump should be reviewed before the MRI
  • aneurysmal vascular clips unless their MR compatibility is documented
    • examination may be performed if the clips or coils were placed after the year 2000
    • safe > 6-8 weeks after the procedure
  • catheters with metallic components (Swan-Ganz catheter)
  • magnetic dental implants
  • an artificial limb unless MR compatibility is documented
  • metal foreign bodies in or near the globe
    • fragment in the eye could move or be displaced and cause injury to the eye or surrounding tissue
    • a screening radiograph or CT of the orbits for the foreign bodies must be performed by a radiologist before the patient enters the scanning room
  • implanted sternal device system (temporal use in children)
  • “Triggerfish” Contact Lens – allows for an automated recording of continuous intraocular pressure; this device is strictly contraindicated for MRI as it can cause severe eye injury
  • gastric reflux device
    • The LINX Reflux Management System is implanted around the lower end of the esophagus – this implant is not MRI-compatible
  • conventional (ferromagnetic) EEG electrodes
    • standard EEG electrodes are made of metal and can be hazardous in an MRI scanner
    • MRI-safe electrodes have been developed; only the MRI-safe portion goes with the patient to the scanner  MR Conditional Quick Connect Electrodes
Relative contraindications
  • joint replacements, osteosynthetic material placed < 6 weeks after implantation or with signs of loosening
  • prosthetic heart valves or annuloplasty rings placed < 6-8 weeks ago
    • if the surgery was performed after the year 2000, the examination can be safely done with a 1.5T scanner
  • stents placed < 6 weeks ago (in an emergency, there is no need to wait for 6 weeks – check the manufacturer’s instructions)
    • there is a slight risk of heating or image distortion, especially in older stents
  • inferior vena cava (IVC) filter placed < 6 weeks ago (use 1.5T)
  • neurostimulation devices
    • MRI should  be performed only in strict accordance with the manufacturer’s conditional guidelines
  • metal embolization material and occluders placed < 6 weeks ago unless their MR compatibility is documented
    • while most embolization materials and occluders are considered MR-compatible, there is a slight risk of heating or image distortion
  • ocular prosthesis
  • medication patch should be removed before the procedure
  • tattoos (including permanent makeup) in the area of interest
    • tattoo must be healed; if <6 weeks old, reschedule the patient
    • iron particles (especially red ink) will cause the tattoo to heat up – use ice packs on any tattoo that is in contact with the bore of the scanner or the MRI coil; encourage the patients to squeeze the communication ball if they experience warmth around their tattoo
    • if the tattoo is within the scan area, a metal artifact may appear on the MRI image
  • gastrointestinal tubes
    • tubes containing no metal components are, by definition, MRI-Safe
    • a unique device in this category is the Edi Catheter, which is considered MRI Unsafe
  • colonoscopy clips (endoclips) placed< 8 weeks ago
    • clips are made of titanium, tantalum, or non-ferromagnetic stainless steel and are labeled as MR-conditional
    • they may pose a risk of heating or image distortion in certain MRI scanners
  • cardiac loop recorders
    • patients with cardiac loop recorders should consult their cardiologist to review the specific product details and safety considerations
    • data stored on the device may be altered or erased – download them before the MRI examination
  • metallic fragments of uncertain origin located near the examined area
    • most pellets and bullets tested for MR compatibility are composed of non-ferromagnetic materials, but there is still a potential risk of heating or image distortion
    • consider the risks/benefits of performing an MRI
    • radiographic screening (plain film radiographs or CT) is recommended for patients with a history of gunshot wounds
  • spinal fixation hardware – the main issue is an artifact and possible heating; a 1.5T scanner should be preferred
  • piercings/microdermal piercings
    • all piercings should be removed or replaced with metal-free alternatives before an MRI
    • surgical metal piercings located outside the area to be scanned may be allowed on a case-by-case basis
  • some other devices and implants may be contraindicated – the radiologist and MRI technologist must assess the type of device
  • fixed orthodontic devices pose no threat to the patient during the MRI scan
  • presence of metal components can cause artifacts, but these can be minimized by changing the scanning plane
  • before the MR examination, the orthodontist should remove the detachable wires, check the strength of the fixation, and write a report stating that the device is MRI-ready
    • devices with retained wire arches may form a closed, electrically conductive loop that can become heated during the MRI examination; therefore, the possibility of thermal damage to the oral mucosa cannot be completely eliminated
    • prior to the examination, MR personnel must instruct the patient to immediately notify the MR operator of any discomfort in the oral cavity (pain, burning).
  • fixed orthodontic devices (locks and rings) must be completely removed before the MRI examination in the jaw area – consider an alternative imaging method
  • ceramic, plastic, or titanium locks should be preferred for patients with medical conditions who are expected to undergo more frequent MRI scans
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  • Intrauterine devices (IUDs) are generally considered safe because most are made of non-metallic materials such as plastic (Mirena, Skyla, Liletta) or copper that are MRI-compatible
  • metal-containing IUDs are MRI-compatible up to a magnetic field strength of 1.5 Tesla (Sammet, 2007)


  • claustrophobic patients may require sedation
  • using larger and open MRI systems might be helpful → claustrophobia and MRI
    • open MRI systems have a larger opening, which allows patients to feel more comfortable and less confined
    • additionally, open MRI systems often have a more comfortable environment, with softer surfaces and less noise

MRI during pregnancy

  • MRI is the preferred imaging modality in pregnancy, whether for maternal or fetal reasons.
  • using a 1.5 T scanner is recommended
  • to date, there are no known adverse effects or specific consequences for fetuses exposed to non-contrast MRI
    • published data indicate no increased risk of fetal malformations, even in the first trimester  [Ray, 2016]
    • there is a growing body of experience with fetal MRI (used to detect brain developmental defects, placental abnormalities, and more) [Griffiths, 2005]
  • gadolinium-based contrast agents (GBCAs) can cross the placenta and enter the fetal circulation
  • GBCAs should be avoided during the examination of a pregnant patient
    • if a contrast study is necessary, the patient must provide informed consent after the risks and benefits have been discussed
    • risks and benefits of alternative imaging techniques, such as ultrasound or CT, should be discussed as well

→ Gadolinium in pregnancy and breastfeeding

Gadolinium contrast agents (GBCAs)

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Magnetic Resonance Imaging Contraindications