Heating induced near deep brain stimulation lead electrodes during magnetic resonance imaging with a 3 T transceive volume head coil

Heating induced near deep brain stimulation (DBS) lead electrodes during magnetic resonance imaging with a 3 T transceive head coil was measured, modeled, and imaged in three cadaveric porcine heads (mean body weight = 85.47 ± 3.19kg, mean head weight = 5.78 ± 0.32kg). The effect of the placement of the extra-cranial portion of the DBS lead on the heating was investigated by looping the extra-cranial lead on the top, side, and back of the head, and placing it parallel to the coil's longitudinal axial direction. The heating was induced using a 641s long turbo spin echo sequence with the mean whole head average specific absorption rate of 3.16W kg ¹. Temperatures were measured using fluoroptic probes at the scalp, first and second electrodes from the distal lead tip, and 6mm distal from electrode 1 (T _6mm). The heating was modeled using the maximum T _6mmand imaged using a proton resonance frequency shift-based MR thermometry method. Results showed that the heating was significantly reduced when the extra-cranial lead was placed in the longitudinal direction compared to the other placements (peak temperature change = 1.5-3.2°C versus 5.1-24.7°C). Thermal modeling and MR thermometry may be used together to determine the heating and improve patient safety online.