Magnetic Resonance Imaging in patients with ICDs and Pacemakers

Prashant Nair, Ariel Roguin,                                                      205

“Magnetic Resonance Imaging in patients with ICDs and Pacemakers”

warranty, heating leads, rapid pacing, alteration of programming, damage of circuitry requiring
replacement and movement of the device.

In 2004, the American College of Radiology (ACR) issued an update of its 2001 MR Safe
Practices Guidelines⁸ in which they reiterate their recommendation that implantable devices
should be a contraindication for MR imaging. They added, however, that decisions for
exceptions should be made on a case-by-case basis and that all MR scans should be performed
under the guidance of both an experienced radiologist and cardiologist/ electrophysiologist, but
noted that "the expertise necessary to safely do so is exceedingly rare throughout the MR industry
today." Thoughtful pre-MR reprogramming, careful monitoring during MR scan and thorough
follow-up must be performed in any device patient considered for MR imaging. Finally a
physician knowledgeable in device therapy and programming should be present throughout the
entire scanning event (Table 3). The authors of the 1.5-T pacemaker study³² agree with the ACR
guidelines that continuous monitoring is needed and that properly trained personnel and
physicians with expertise in adjusting device programming interrogate the devices before and
after the scan. Adherence to these practice guidelines may ensure the implantable cardiac device
patient can safely undergo MR imaging (Table 4). As suggested by the aforementioned studies, it
may be an appropriate time to reconsider whether the presence of an implantable cardiac device
should be an absolute contraindication to MR imaging.

Table 3: Magnetic Resonance Imaging and Pacemakers: Safety Concerns and Guidelines.

* Due to higher degree of interaction between MRI and ICD, the threshold for imaging is higher
than for pacemakers.

Table 4: Technical aspects in MR imaging of patients with pacemakers/ICDs

Arranging the procedure:

Procedure must be approved by attending radiologist

A Cardiology consult must be obtained to determine pacemaker- or ICD-dependency.

Procedure will be scheduled with Radiology and Cardiology in coordinated fashion.

MR imaging of pacemaker or ICD patients will only be performed in a main Hospital.

The exam will only be performed on weekdays during regular business hours.

Technical (MRI):

Field strength is limited to 1.5 T.

Send/Receive volume coils are preferred over surface coils.

Technical (Pacemaker/ICD):

Device must have been in place preferably for 4-8 weeks prior to MR imaging.

Immediately prior to MR imaging, the pacemaker must be programmed to OFF or must be
programmed to sub threshold outputs (rate response and ventricular rate regulation features will
need to be programmed OFF). ICD programmed to therapy off.

Qualified personnel will perform a full device interrogation prior and immediately after MR scan

Indian Pacing and Electrophysiology Journal (ISSN 0972-6292), 5(3): 197-209 (2005)

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