MRI contraindications

MR Contraindications

Cardiovascular Devices

Device	MR Category	Comments
Aortic stent grafts	Most MR Safe	Zenith AAA and TAA endovascular grafts (Cook) = MR Conditional
Cardiac closure and occluder devices	Most MR Safe (some MR Conditional)
Coronary artery stents	Most MR Safe (some MR Conditional)	Check individual type
Embolization coils	Most MR Safe (some MR Conditional)
Loop recorder (Event monitor)	MR Conditional?	Stored data may be affected
Mechanical cardiac valves	Most MR Safe (some MR Conditional)	Ie. prosthetic heart valves and annuloplasty rings
Sternal wires	Generally considered MR safe
Hemodynamic monitoring and temporary pacing devices	MR Unsafe
Hemodynamic support devices	MR Unsafe	I.e. Intraaortic balloon pump and ventricular assist devices
IVC filters	Most MR Safe (some MR Conditional)	Weakly ferromagnetic devices [e.g. Gianturco bird nest IVC filter (Cook), stainless steel Greenfield vena cava filter (Boston Scientific)]: after six weeks as long as no reason to suspect improper positioning or movement
Permanent pacemakers and ICDs	Strong relative contraindication vs. MR Unsafe	Absolute contraindication: pacemakers or ICDs with known lead fractures
Peripheral vascular stents	Most MR Safe (some MR Conditional)	Check individual type
Pulmonary artery monitoring/thermodilution catheters	MR Unsafe (unless otherwise specified)	I.e. Swan-Ganz catheter and similar catheters
Temporary pacemaker	MR Unsafe	I.e. External pulse generators or temporary pacing leads
Retained transvenous pacemaker and defibrillator leads	Strong relative contraindication vs. MR Unsafe	Approached same as those with pacemakers or ICDs (see above)

Permanent pacemakers and implantable ICDs

• Only if no alternative diagnostic test is available and the potential benefit to the patient clearly outweighs the potential risks
• If performed, the pacemaker/ICD should be interrogated before and after the procedure
• Registry of non-MRI conditional pacemakers in NEJM article with nonthoracic MRI at field strength of 1.5 teslas suggested that lead or device failure does not occur
  • 1000 cases of pacemakers and 500 cases of ICD in study
  • No deaths, lead failures, losses of capture, or ventricular arrhythmias occurred during MRI
  • Industry funded study, with strict criteria for inclusion
• Risks:
  • Pacemaker/ICD dysfunction
  • Pacemaker/ICD damage
  • Arrhythmia
  • Death

Non-Cardiovascular

Device	MR Category	Comments
Nerve stimulators	MR Unsafe
Cochlear implants	MR Unsafe
Aneurysm clips	Ferromagnetic: MR Unsafe; Non/weakly-ferromagnetic: MR Safe	Requires specific information about clip material
Dental materials (alloys, wires, splints, and prostheses)	MR Safe
Neurosurgical halo pins	MR unsafe?
Transdermal patches	If contain aluminum or other metals (in non-adhesive backing): MR Unsafe	Remove before MR. Examples include certain clonidine, nicotine, scopolamine, testosterone, or fentanyl patches
Unstable patient	MR Conditional	Probably should avoid unless an urgent clinical indication without acceptable alternative

Other

• Pregnancy: Unknown (if any, probably low)
  • Gadolinium-based contrast not recommended unless benefit justifies risk (crosses the placenta)
• Claustrophobia
• Agitated
• Very Obese (depending on system)

MR (Gadolinium-Based) Contrast

Background

• Unlike iodinated contrast, MR contrast has few side effects and rarely cause anaphylaxis
• It does cross the placenta

Specific Groups

• Pregnancy (see above)
  • Gadolinium-based contrast not recommended unless benefit justifies risk
• Moderate to severe chronic kidney disease:
  • Contrast nephropathy can occur (contraindicated)
• Dialysis and hepatorenal patients in the perioperative liver transplant period
  • Associated Nephrogenic Systemic Fibrosis (contraindicated)

Key

• MR Safe: Generally safe
• MR Conditional: Weigh risk/benefit (relative contraindication)
• MR Unsafe: Generally contraindicated (absolute contraindication)

See Also

• MRI (main)
• CT/MRI size limits