Variability in RF-induced heating of a deep brain stimulation implant across MR systems

J Magn Reson Imaging. 2006 Dec;24(6):1236-42. doi: 10.1002/jmri.20769.


Purpose: To compare the MRI-related heating per unit of specific absorption rate (SAR) profile of a conductive implant between two 1.5-Tesla/64 MHz MR systems using a transmit/receive (t/r) head coil configuration.

Materials and methods: Deep brain stimulation (DBS) leads were configured within a gel-filled phantom of the human head and torso. Temperature variation at each of four contacts of the bilaterally-placed leads was monitored using fluoroptic thermometry. MRI was performed using the t/r head coils of two different-generation 1.5-Tesla MR systems from the same manufacturer. Temperature changes were normalized to SAR values for the head (DeltaT/SAR-H), and the slope of this DeltaT/SAR-H by time relationship was compared between the two scanners.

Results: The DeltaT/SAR-H for the implant ranged from 3.5 to 5.5 times higher on one MR system as compared to the other (P < 0.01) depending on the measurement site.

Conclusion: The findings support previous observations that console-reported SAR does not constitute a reliable index of heating for elongated, conductive implants, such as the DBS hardware system tested. In contrast to our previous findings using a t/r body coil, the data presented here reveal marked differences between two MR systems using t/r head coils (the coil configuration was consistent with the implant manufacturer's imaging guidelines). J. Magn. Reson. Imaging 2006. (c) 2006 Wiley-Liss, Inc.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Body Temperature / physiology*
  • Body Temperature / radiation effects*
  • Brain / physiology*
  • Brain / radiation effects*
  • Deep Brain Stimulation*
  • Humans
  • Magnetic Resonance Imaging*
  • Phantoms, Imaging
  • Radio Waves*
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Thermography