How are MRIs performed in patients with implantable cardioverter-defibrillators (ICDs)?

Updated: Feb 13, 2017
  • Author: Daniel M Beyerbach, MD, PhD; Chief Editor: Jeffrey N Rottman, MD  more...
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Answer

Magnetic resonance imaging (MRI) scans were safely performed in a study of 15 patients with subcutaneous ICDs (S-ICD System). All scans (5 of the brain, 4 of the heart, 6 of the L-spine, and 2 of the C-spine) were performed at least 6 weeks after implantation of the ICD, which was turned off during imaging. There was no evidence of movement or rotation of the ICD, and no malfunctions were found on postscan checks up to 12 months later.  However, as MRI-conditional devices become specifically approved, MRI studies of nonconditional devices is generally avoided at many centers—or performed only on specific protocols. Protocols for the imaging of conditional devices are also typically specified, and they may dictate certain programming adjustments, lead parameters, or delay after implantation.

MRI imaging of the brain, C-spine, and L-spine was free of artifacts. Heart imaging showed no major artifacts in the right chamber, but interference in the left chamber view. The procedure was repeated with reduced radiofrequency field exposure, reduced turbo factors, increased repetition time, and reduced flip angle in 2 patients who complained of heating over the subcutaneous pocket caused by the thermistor during their first L-spine scan. [67]

Rashid and colleagues developed a modified wideband late gadolinium enhancement (LGE) MRI technique that can overcome hyperintensity image artifacts caused by implanted cardiac devices. In their study of 12 patients with ICDs, use of the wideband LGE sequence eliminated the severe, uninterpretable hyperintensity artifacts in the left ventricular wall that occurred with conventional LGE technique, thereby enabling confident evaluation of myocardial viability. [68]


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