Variability in RF-induced heating of a deep brain stimulation implant across MR systems
✍ Scribed by Kenneth B. Baker; Jean A. Tkach; Micheal D. Phillips; Ali R. Rezai
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- English
- Weight
- 395 KB
- Volume
- 24
- Category
- Article
- ISSN
- 1053-1807
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✦ Synopsis
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). J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.