Reducing RF-Induced Heating Near Implanted Leads Through High-Dielectric Capacitive Bleeding of Current (CBLOC)

Laleh Golestanirad*, Leonardo M. Angelone, John Kirsch, Sean Downs, Boris Keil, Giorgio Bonmassar, Lawrence L. Wald

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


Patients with implanted medical devices such as deep brain stimulation or spinal cord stimulation are often unable to receive magnetic resonance imaging (MRI). This is because, once the device is within the radio frequency (RF) field of the MRI scanner, electrically conductive leads act as antenna, amplifying the RF energy deposition in the tissue and causing possible excessive tissue heating. Here, we propose a novel concept in lead design in which 40-cm lead wires are coated with a ∼1.2-mm layer of high dielectric constant material (155 < ϵr < 250) embedded in a weakly conductive insulation (σ = 20 S/m). The technique called high-dielectric capacitive bleeding of current (CBLOC) works by forming a distributed capacitance along the lengths of the lead, efficiently dissipating RF energy before it reaches the exposed tip. Measurements during RF exposure at 64 and 123 MHz demonstrated that CBLOC leads generated 20-fold less heating at 1.5 T and 40-fold less heating at 3 T compared to control leads. Numerical simulations of RF exposure at 297 MHz (7 T) predicted a 15-fold reduction in specific absorption rate of RF energy around the tip of CBLOC leads compared to control leads.

Original languageEnglish (US)
Article number8598958
Pages (from-to)1265-1273
Number of pages9
JournalIEEE Transactions on Microwave Theory and Techniques
Issue number3
StatePublished - Mar 2019


  • Electrode leads
  • MR conditional
  • RF heating
  • finite-element method
  • high field
  • high-dielectric material
  • magnetic resonance imaging (MRI)
  • medical implants
  • numerical simulations
  • radio frequency (RF) safety
  • specific absorption rate (SAR)

ASJC Scopus subject areas

  • Radiation
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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