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

Kenneth B. Baker, Jean A. Tkach, Micheal D. Phillips, Ali R. Rezai

Research output: Contribution to journalArticlepeer-review

69 Scopus citations

Abstract

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 (ΔT/SAR-H), and the slope of this ΔT/SAR-H by time relationship was compared between the two scanners. Results: The ΔT/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).

Original languageEnglish (US)
Pages (from-to)1236-1242
Number of pages7
JournalJournal of Magnetic Resonance Imaging
Volume24
Issue number6
DOIs
StatePublished - Dec 2006

Keywords

  • Deep brain stimulation
  • Implants
  • Magnetic resonance imaging, bioeffects
  • Magnetic resonance imaging, safety
  • Neurostimulation systems
  • Specific absorption rate

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