title: Measuring RF-induced currents inside implants: Impact of device configuration on MRI safety of cardiac pacemaker leads.
abstract: Radiofrequency (RF)-related heating of cardiac pacemaker leads is a serious concern in magnetic resonance imaging (MRI). Recent investigations suggest such heating to be strongly dependent on an implant's position within the surrounding medium, but this issue is currently poorly understood. In this study, phantom measurements of the RF-induced electric currents inside a pacemaker lead were performed to investigate the impact of the device position and lead configuration on the amount of MRI-related heating at the lead tip. Seven hundred twenty device position/lead path configurations were investigated. The results show that certain configurations are associated with a highly increased risk to develop MRI-induced heating, whereas various configurations do not show any significant heating. It was possible to precisely infer implant heating on the basis of current intensity values measured inside a pacemaker lead. Device position and lead configuration relative to the surrounding medium are crucial to the amount of RF-induced heating in MRI. This indicates that a considerable number of implanted devices may incidentally not develop severe heating in MRI because of their specific configuration in the body. Small variations in configuration can, however, strongly increase the risk for such heating effects, meaning that hazardous situations might appear during MRI.
authors.affiliation: Internal Medicine I, University Hospital Würzburg, Germany. nordbeck@physik.uni-wuerzburg.de
authors.forename: Peter
authors.initials: P
authors.lastname: Nordbeck
authors.forename: Ingo
authors.initials: I
authors.lastname: Weiss
authors.forename: Philipp
authors.initials: P
authors.lastname: Ehses
authors.forename: Oliver
authors.initials: O
authors.lastname: Ritter
authors.forename: Marcus
authors.initials: M
authors.lastname: Warmuth
authors.forename: Florian
authors.initials: F
authors.lastname: Fidler
authors.forename: Volker
authors.initials: V
authors.lastname: Herold
authors.forename: Peter M
authors.initials: PM
authors.lastname: Jakob
authors.forename: Mark E
authors.initials: ME
authors.lastname: Ladd
authors.forename: Harald H
authors.initials: HH
authors.lastname: Quick
authors.forename: Wolfgang R
authors.initials: WR
authors.lastname: Bauer
mesh_terms: D001822:Body Burden; D002058:Burns, Electric / Q000209:etiology / Q000517:prevention & control*; D004567:Electrodes, Implanted; D019544:Equipment Failure Analysis; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000009:adverse effects / Q000379:methods*; D010138:Pacemaker, Artificial; D019736:Prostheses and Implants; D011829:Radiation Dosage; D011874:Radiometry / Q000295:instrumentation / Q000379:methods*; D012062:Relative Biological Effectiveness