MRI-induced heating on patients with implantable cardioverter-defibrillators and pacemaker: Role of the lead structure

Magnetic Resonance Imaging (MRI) induced heating on patients with pacemaker (PM) or implantable cardioverter-defibrillator (ICD) can pose severe health risks. Experimental studies in this field have shown a great variability in results and revealed that several aspects can affect the amount of heating induced at the lead tip. The structural parameters of the lead are one of these. In this study we performed in-vitro temperature measurements of PM/ICD leads inside a human trunk simulator exposed to the RF field of a 1.5T MRI scanner. A total of 26 leads were tested (23 PM leads, 3 ICD leads) and the temperature increases induced by the RF field ranged from 2.1°C to 15.0°C. Significant heating was observed not only at the lead tip, but also at the ring (as high as 4.2°C), even if not in all the bipolar leads tested. Active-fix leads showed higher temperature increases than passive-fix ones (4.7°C versus 7.4°C).