NEURAL PROBE BEHAVIOUR IN MAGNETIC RESONANCE
Relevant for Research Area
Dr. Matthias Wapler (Contact PI)
Magnetic resonance imaging is a highly useful and versatile diagnostic procedure, but it poses a harsh electromagnetic environment: The constant homogeneous magnetic field, a strong dynamic gradient magnetic field and a radio frequency field. All of these can interact with different structures of neural implants, resulting in heating, forces, induced electric signals and, in converse, field distortion. Hence, the diagnostic imaging value may suffer, the implant may get damaged or the patient safety can be jeopardized which is why such implants are initially contraindicated to MRI. Hence, our goal is to enable the development of MR compatible neural implants. We first develop the testing instrumentation: A modular MR probehead with different measurement channels and an integrated camera and methods to determine the magnetic susceptibility of arbitrary samples and MR artifacts of implant structures. We then develop design rules for MR-safe implants, supported by systematic measurements.
We have developed a highly precise method to measure the magnetic susceptibility of materials using MRI with a large data base of measured material data and obtained systematic data on the MR artifacts of different structures. With the probehead completed and the integration of the camera in progress, we are next moving towards device testing and the systematic measurements of heating, forces and induced voltages to support the development of the theoretical framework of the design rules.
Wapler MC, Leupold J, Dragonu I, v. Elverfeld D, Zaitsev M, Wallrabe U (2014) Magnetic properties of materials for MR engineering, micro-MR and beyond. Journal of Magnetic Resonance, volume: 242, pp. 233-42.