Simple design changes to wires to substantially reduce MRI-induced heating at 1.5 T: implications for implanted leads

Magn Reson Imaging. 2005 Oct;23(8):887-91. doi: 10.1016/j.mri.2005.07.005. Epub 2005 Oct 13.

Abstract

Reductions in MRI-induced heating at 1.5 T resulting from a simple design change to coiled wires were investigated. MRI-induced heating was assessed for two different coiled wire forms (length, 26 cm): (1) multi-filar coiled wire form and (2) multi-filar coiled wire form having a different coiled pitch, providing an air gap spacing between adjacent five-filar coil loops. Each wire had an electrode and was insulated to create a lead, similar to that which would be used for a medical implant. The wire forms were placed in a gelled-saline-filled head/torso phantom and imaged at 1.5 T [whole-body average specific absorption rate (SAR), 1.79 W/kg]. Fluoroptic thermometry probes were used to measure temperatures at the distal ends of the wires. The experiments demonstrated a substantial reduction in MRI-induced heating for the modified wire compared to the unmodified wire (i.e., 10.5 degrees C difference observed in one experiment and 26 degrees C difference in another). These findings have important implications for MRI-induced heating of leads used for medical implants.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Electric Wiring / instrumentation*
  • Electrodes, Implanted*
  • Equipment Design / methods
  • Hot Temperature*
  • Magnetic Resonance Imaging / instrumentation*
  • Magnetic Resonance Imaging / methods
  • Phantoms, Imaging
  • Temperature
  • Time Factors