Modern Pacemaker and Implantable Cardioverter/Defibrillator Systems Can Be Magnetic Resonance Imaging Safe

Abstract

Background-MRI has unparalleled soft-tissue imaging capabilities. The presence of devices such as pacemakers and implantable cardioverter/defibrillators (ICDs), however, is historically considered a contraindication to MRI. These devices are now smaller, with less magnetic material and improved electromagnetic interference protection. Our aim was to determine whether these modern systems can be used in an MR environment. Methods and Results-We tested in vitro and in vivo lead heating, device function, force acting on the device, and image distortion at 1.5 T. Clinical MR protocols and in vivo measurements yielded temperature changes Ͻ0.5°C. Older (manufactured before 2000) ICDs were damaged by the MR scans. Newer ICD systems and most pacemakers, however, were not. The maximal force acting on newer devices was Ͻ100 g. Modern (manufactured after 2000) ICD systems were implanted in dogs (nϭ18), and after 4 weeks, 3-to 4-hour MR scans were performed (nϭ15). No device dysfunction occurred. The images were of high quality with distortion dependent on the scan sequence and plane. Pacing threshold and intracardiac electrogram amplitude were unchanged over the 8 weeks, except in 1 animal that, after MRI, had a transient (Ͻ12 hours) capture failure. Pathological data of the scanned animals revealed very limited necrosis or fibrosis at the tip of the lead area, which was not different from controls (nϭ3) not subjected to MRI. Conclusions-These

Evaluation of the Susceptibility Artifacts and Tissue Injury Caused by Implanted Microchips in Dogs on 1.5T Magnetic Resonance Imaging

“…The extent of the temperature rise is even higher when the implant is smaller or has an antenna [6,12]. Evaluation of the tissue effects attributable to MRI-induced heating and migration of the implant have been conducted by histological examinations involving experimental animals to determine safety in patients with implants [9,13]. In our histopathological results, there were no considerable differences in tissues of implant sites between MR and control groups and evidence for implant migration in the body was not observed.…”

Interaction between the RF Field of MRI Apparatus and Pacemakers

“…The obtained temperature increases ranged from 0.1 to 23.5 °C, depending on the electrode type. Roguin et al (2004) applied to PMs placed in a box model of the thorax sequences with SAR less than 1.4 W/kg (regular clinical MR protocol) and 3.54 W/kg (non clinical protocol). Non clinical protocol gave rise to temperature increments at the catheter tip from 1.5 to 5.7 °C, while for clinical protocol the maximal heating was 0.9 °C.…”

Evaluation of global left ventricular function assessment by dual-source computed tomography compared with MRI

“…These devices cause large image artifacts on the MRI and their intracardiac leads may warm up and possibly even cause perforation at the tip. Although there is increasing evidence that MRI examination may be performed safely in some specific cases, pacemakers and defibrillators still remain a contraindication [21].…”