RT Journal Article
SR Electronic
T1 Reducing RF-induced Heating near Implanted Leads through High-Dielectric Capacitive Bleeding of Current (CBLOC)
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 456533
DO 10.1101/456533
A1 Laleh Golestanirad
A1 Leonardo M Angelone
A1 John Kirsch
A1 Sean Downs
A1 Boris Keil
A1 Giorgio Bonmassar
A1 Lawrence L Wald
YR 2018
UL http://biorxiv.org/content/early/2018/11/19/456533.abstract
AB 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 radiofrequency (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 40cm lead wires are coated with a ~1.2mm 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, or 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 MHz 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 (7T) predicted a 15-fold reduction in specific absorption rate (SAR) of RF energy around the tip of CBLOC leads compared to control leads.