MRI

Magnetic Resonance Imaging

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Magnetic Resonance Imaging, MRI, MRI and Cardiac Devices, MRI and Pacemaker, MRI and Defibrillator, MRI Contraindication

  • Contraindications
  • General
  1. Ferromagnetic Intracranial Aneurysm clips (non-ferromagnetic clips are MRI safe)
  2. Metallic foreign body in eye or brain
  3. Cochlear Implant (MRI Conditional)
  4. TENS unit
  • Contraindications
  • Legacy Cardiac Devices
  1. Background
    1. Newer cardiac devices are defined as MRI Conditional (whereas legacy devices do not carry the designation)
  2. Adverse Effects related to legacy devices in MRI
    1. Power-On Reset Event (most common, may reset functional mode)
    2. Altered sensing and pacing thresholds
    3. Generator failure
    4. Device battery depletion
    5. False Positive sensing that triggers antitachycardia pacing or electrical Defibrillation shocks
  3. Safety
    1. Legacy devices may undergo MRI in some centers with safety protocols and electrophysiology available
    2. Legacy cardiac devices appear to be safe in MRI if safety protocols in place
      1. Russo (2017) N Engl J Med 376:755-64 [PubMed]
  4. Affected devices
    1. Legacy Pacemakers
    2. Legacy Implantable Defibrillator (AICD)
  • Safety
  • Allowed metal objects
  1. Coronary stents
  2. Surgical Clips
  • Safety
  • Pregnancy
  1. MRI appears safe in pregnancy
  2. However, Gadolinium is associated with Stillbirths and a small increased risk of rheumatologic or inflammatory conditions
  3. Ray (2016) JAMA 316(9):952-61 +PMID:27599330 [PubMed]
  • Precautions
  1. Magnetic field is always on
  2. Do not enter scan room with a metallic object
    1. Stethoscope
    2. Tuning fork
    3. Reflex hammer