John S. Thornton1, David W. Carmichael2, Shahid Khan3, Clare J. Fowler4, Thomas M. Kessler4
1Lysholm Department of Neuroradiology, National Hosiptal for Neurology and Neurosurgery, UCLH NHS Foundation Trust, London, UK; 2Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK; 3Department of Uro-Neurology, The National Hospital for Neurology and Neurosurgery, UCLH NHS Foundation Trust, London, UK; 4Department of Uro-Neurology, National Hospital for Neurology and Neurosurgery, UCLH NHS Foundation Trust, London, UK
A sacral neuromodulation system was located in an anthropomorphic tissue-equivalent gel phantom and electrode temperatures monitored with a fibre-optic thermometer. A 6.5 min FSE acquisition was performed in a 3Tesla Siemens system at a number of landmark positions and sequence SARS up to 2W/kg whole-body. When landmarked on the phantom head, electrode-associated temperature rises were 0.10oC or less. At other landmark positions, sequence SAR and temperature rises varied widely with position, but electrode-associated temperature increases were always < 2oC. MRI in patients with sacral neuromodulation implants may be safe but landmark, scanner and software-level specific SAR limits must be applied.