What devices are Magnetic Resonance Imaging (MRI) compatible at 3 Tesla (3T)?

MRI-Compatible Devices at 3 Tesla

Most prosthetic heart valves, coronary stents, and modern penile prostheses are MRI-compatible at 3 Tesla field strength, while certain electronic devices like pacemakers and neurostimulators require specific evaluation and protocols. 1, 2

General MRI Safety Considerations at 3T

• MRI is very safe with no short or long-term ill effects at current field strengths (≤3T), though claustrophobia affects 3-7% of patients 1
• The primary safety concern is preventing ferromagnetic objects from entering the scanner area as they become dangerous projectiles 1
• Both 1.5T and 3T field strengths are currently in clinical use, with 3T offering higher spatial resolution but more susceptibility artifacts than 1.5T 1, 3
• At 3T, the 0.5mT safety limit may extend beyond the magnet room, requiring appropriate barriers and warning notices 1

MRI-Compatible Implants and Devices

Cardiovascular Devices

• Most prosthetic heart valves (mechanical or bioprosthetic) and all coronary stents are considered safe in MRI environments up to 3T 1
• Metallic implants such as hip prostheses, mechanical heart valves, and sternal sutures present no hazard as they are non-ferromagnetic (though they may cause local image artifacts) 1
• Modern pacemakers and implantable cardioverter-defibrillators (ICDs):
  • MR-conditional pacemakers allow non-cardiac MRI scans under controlled conditions specified by the manufacturer 1
  • Recent evidence suggests that even conventional (non-MR-conditional) pacemakers and ICDs may be safely scanned at 3T with appropriate protocols and monitoring 4

Neurosurgical Devices

• Programmable shunts for hydrocephalus may have pressure settings changed by MRI scanning:
  • Many modern programmable shunts are unaffected by MR scanners up to 3T, but settings should be checked before and after scanning 1
  • Older models may require assessment by the neurosurgical team before scanning and resetting after the scan 1

Neurostimulators and Implantable Devices

• Traditional neurostimulators (vagal nerve, deep brain, spinal cord) were contraindicated for MRI 1
• Newer MR-conditional neurostimulators can be scanned under specific manufacturer-recommended conditions 1
• Implantable drug pumps (e.g., baclofen pumps) may discharge their entire dose during scanning and should be emptied before MRI 1

Ophthalmic Implants

• iStent implants (titanium devices for glaucoma) show no significant movement, heating, or image artifacts during 3T MRI scanning 5

Dental Devices

• Magnetic dental attachments show minimal radiofrequency-induced heating at 3T but may experience magnetically induced deflection forces exceeding acceptable limits 6
• Cast magnetic alloy dental devices should be removed before MRI scanning 6

Surgical Implants

• Metallic skin closure staples and vessel ligation clips made of stainless steel show only minor magnetic field interactions at 3T (acceptable from a safety perspective) 7
• Surgical implants typically cause minimal heating (temperature changes ≤1.6°C) 7

Urological Devices

• Modern penile prostheses are MRI-compatible at 1.5 Tesla field strength 8, 2

Special Considerations for 3T vs 1.5T

• 3T offers faster acquisition of dynamic sequences with higher spatial resolution 1
• 1.5T has reduced susceptibility artifacts compared to 3T 1
• Field strengths greater than 3T are not recommended for clinical use 1
• When scanning the chest at 3T, a large bore magnet is preferable to avoid field inhomogeneity at the level of the diaphragm 1

Common Pitfalls and Precautions

• Always conduct thorough safety screening before every MRI exam to rule out contraindications 1
• MR-conditional devices may still produce significant artifacts that can affect image quality 1
• Electronic implants (infusion or monitoring devices) were traditionally considered absolute contraindications, though this is evolving with newer MR-conditional devices 1
• "Biohacking" implants (self-implanted technological enhancements like fingertip magnets or RF identification chips) should be considered during patient screening 1
• Even MR-compatible devices may cause local image artifacts that can interfere with diagnostic quality 1, 7