Patients with pacemakers and cardiac defibrillators undergoing I.5-T MRI exams: Is it safe?

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 - Implantable Defibrillator

More than three million individuals in the U.S. live with cardiac implantable electronic devices (CIEDs) such as pacemakers and implantable cardioverter-defibrillators (ICDs). But what happens when one of them need an MRI? Is it safe?

According to a recent study published by the American Journal of Roentgenology, when radiologists and cardiac electrophysiologists work together, patients with conventional and MRI-conditional cardiac implantable electronic devices (CIEDs) can safely undergo 1.5-T MRIs.

Lead author Juan C. Camacho, MD, department of radiology and imaging sciences at the Emory University School of Medicine, and colleagues explained that at their facility, radiologists and cardiac electrophysiologists collaborate when it is time to image a patient with a CIED. The radiologist has the cardiac electrophysiologist examine the device before and after the exam, documenting “programming changes, malfunctions, and intraprocedural events.” It is then determined whether the diagnostic questions at hand were answered or if artifacts had a negative impact on the image.

To test the system, 113 MRI examinations were performed on a total of 104 patients with CIEDs. The devices had to be programmed before the MRI more than 62 percent of the time, and “no significant changes in lead parameters” were found.

And the overall image quality, Camacho et al. found, was good, even when the device was in the field of view (FOV).

“Diagnostic questions were answered in all cases in the current study,” the authors wrote. “When the device was not directly included in the FOV, no artifacts related to the device were described in the imaging report or were visible on the images in retrospective review. When the device was included in the FOV, that is, in chest, cardiac, and abdominal (which included the lung bases) studies, artifacts related to the pulse generator and leads were described in the dictated report as limiting the examination in a minority of cases.”

In 3.5 percent of the exams, artifacts related to the CIEDs were visible when the pulse generator was included in the FOV. This, Camacho and colleagues explained, “limited evaluation of tissues immediately adjacent to the pulse generator.”

“Thus, before contemplating MRI for a patient with a CIED, one must consider that the area immediately around the pulse generator or leads may be obscured by artifact,” the authors wrote.

This study did have limitations, the research team said, including the fact that just 5 percent of the patients studied were pacemaker dependent.

“The sample size was therefore too small to draw meaningful conclusions about pacemaker-dependent patients,” the authors wrote.