Janneke Ansems1, Anja G. van der Kolk2, Hugo Kroeze2, Nico AT van den Berg3, Gert-Jan de Borst4, Peter R. Luijten2, Andrew G. Webb5, W Klaas Jan Renema6, Dennis WJ Klo
1Radboud University Nijmegen Medical Center, Nijmegen, Netherlands; 2Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands; 3Department of Radiotherapy, University Medical Center Utrecht, Utrecht, Netherlands; 4Department of Vascular Surgery, University Medical Center Utrecht, Utrecht, Netherlands; 5Department of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands; 6Department of Radiology, Radboud University Nijmegen Medical Center, Nijmegen, Netherlands
At increasing magnetic field strength, safety issues regarding RF heating of metallic implants become increasingly important. Although many implants have been tested at lower field strengths, these tests are relatively lacking at (ultra)high field. Based on theoretical assumptions regarding low Q-values, being the dominant factor in tissue heating at (ultra)high field, we tested our theory that scanning metallic implants like stents is RF-safe. Using both experimental Q-value measurements, temperature experiments using commonly used vascular stents scanned at 7.0 Tesla MRI with 3-times SAR-limit, displacement measurements and an in vivo 7T experiment, we show that scanning peripheral stent grafts is RF-safe.
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