title: Complexity of MRI induced heating on metallic leads: experimental measurements of 374 configurations.
abstract: BACKGROUND
  MRI induced heating on PM leads is a very complex issue. The widely varying results described in literature suggest that there are many factors that influence the degree of heating and that not always are adequately addressed by existing testing methods.
  
  
  METHODS
  We present a wide database of experimental measurements of the heating of metallic wires and PM leads in a 1.5 T RF coil. The aim of these measurements is to systematically quantify the contribution of some potential factors involved in the MRI induced heating: the length and the geometric structure of the lead; the implant location within the body and the lead path; the shape of the phantom used to simulate the human trunk and its relative position inside the RF coil.
  
  
  RESULTS
  We found that the several factors are the primary influence on heating at the tip. Closer locations of the leads to the edge of the phantom and to the edge of the coil produce maximum heating. The lead length is the other crucial factor, whereas the implant area does not seem to have a major role in the induced temperature increase. Also the lead structure and the geometry of the phantom revealed to be elements that can significantly modify the amount of heating.
  
  
  CONCLUSIONS
  Our findings highlight the factors that have significant effects on MRI induced heating of implanted wires and leads. These factors must be taken into account by those who plan to study or model MRI heating of implants. Also our data should help those who wish to develop guidelines for defining safe medical implants for MRI patients. In addition, our database of the entire set of measurements can help those who wish to validate their numerical models of implants that may be exposed to MRI systems.
authors.affiliation: Dept. of Technologies and Health, Italian National Institute of Health, Roma, Italy. eugenio.mattei@iss.it
authors.forename: Eugenio
authors.initials: E
authors.lastname: Mattei
authors.forename: Michele
authors.initials: M
authors.lastname: Triventi
authors.forename: Giovanni
authors.initials: G
authors.lastname: Calcagnini
authors.forename: Federica
authors.initials: F
authors.lastname: Censi
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Kainz
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Mendoza
authors.forename: Howard I
authors.initials: HI
authors.lastname: Bassen
authors.forename: Pietro
authors.initials: P
authors.lastname: Bartolini
mesh_terms: D004559:Electric Wiring / Q000295:instrumentation*; D004567:Electrodes, Implanted; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006358:Hot Temperature; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods*; D008670:Metals / Q000528:radiation effects*; D013817:Thermography
chemical_list: D008670:Metals