Novel test field diversity method for demonstrating magnetic resonance imaging safety of active implantable medical devices.

Novel test field diversity method for demonstrating magnetic resonance imaging safety of active implantable medical devices. Phys Med Biol. 2020 Feb 11;: Authors: Yao A, Zastrow E, Neufeld E, Cabanes-Sempere M, Samaras T, Kuster N Abstract Electromagnetic (EM) radiofrequency (RF) safety testing of elongated active implantable medical devices (AIMD) during magnetic resonance imaging (MRI) requires an RF response model of the implant to assess a wide range of exposure conditions. The model must be validated using a sufficiently large set of incident tangential electric field (Etan) conditions that provide diversified exposure. Until now, this procedure was very time consuming and often resulted in poorly definedEtanconditions. In this paper, we propose a test field diversity (TFD) validation method that provides more diverse exposure conditions of high fidelity, thereby decreasing the number of implant routings to be tested. The TFD method is based on the finding that the amplitude and phase ofEtanalong a single lead path in a cylindrical phantom can be sufficiently varied by changing the polarization of the incident 64 and 128 MHz magnetic fields inside standard birdcage test coils. The method is validated, its benefits are demonstrated, and an uncertainty budget is developed. First, the numerically determined field conditions were experimentally verified. The RF transfer function of a 90 cm long spinal cord stimulator was successfull...
Source: Physics in Medicine and Biology - Category: Physics Authors: Tags: Phys Med Biol Source Type: research