MRI Compatibility Numerical Simulation & Testing
Exponent performs magnetic resonance imaging (MRI) compatibility testing of medical devices and finite element analysis (FEA) simulation of their interaction with the radiofrequency (RF) field.
We apply advanced numerical modeling techniques to evaluate RF-induced heating and identify worst case heating locations and boundary conditions. The worst case conditions for a given device or family of device components depend greatly on the geometrical features, materials, position, orientation of the device and the applied RF frequency. We then use this data to verify, validate and provide rationale for our experimental approach.
Through our A2LA-accredited laboratories, we assist our clients in the feasibility and verification stages of product development as they optimize their device designs for use in an MRI environment. We also assist medical device manufacturers in validating MRI-related performance safety and compatibility, characterizing and managing MRI environment related risk, and meeting regulatory labeling requirements through physical testing of the worst case matrix for each product.
We have performed MRI simulation and testing on a variety of passive and active medical devices including implantable cardiovascular, pulmonary, spinal, neurosurgical and orthopedic devices. We have also tested non-implantable medical devices designed to be used within the MRI environment. We provide analysis and guidance to clients with regard to FDA submission in the context of performance to standards for localized heating, displacement, and torque due to interactions with the magnetic and electromagnetic fields associated with an MR scanner. Exponent’s analytical techniques allow manufacturers to determine the risks associated with already-implanted devices and to formulate a strategy for serving the needs of users and patients. Exponent provides analysis and labeling guidelines for use in formulating a strategy for marketing the devices and to guide submissions to regulatory authorities. We also assist manufacturers with failure analysis when needed, including investigation of injuries in the MRI environment.
We have the capability—and are accredited to ISO 17025—to test at 1.5 T and 3 T in accordance with all applicable ASTM standards (listed below). Exponent also has arrangements with regional research institutions to conduct studies at higher and lower field strength, if needed. Exponent is active in the standards committees related to MRI compatibility testing and is currently implementing the second draft of ISO/TS 10974, in anticipation of its release later this year.
FDA Guidance, Standards and Technical Specifications
- Guidance for Industry and FDA Staff: Establishing Safety and Compatibility of Passive Implants in the Magnetic Resonance (MR) Environment Document issued on: December 11, 2014
- Draft Guidance for Industry and FDA Staff: Assessment of Radiofrequency-Induced Heating in the Magnetic Resonance (MR) Environment for Multi-Configuration Passive Medical Devices, issued on June 29, 2015
- ASTM F2052 – Standard Test Method for Measurement of Magnetically Induced Displacement Force on Medical Devices in the Magnetic Resonance Environment
- ASTM F2119 – Standard Test Method for Evaluation of MR Image Artifacts from Passive Implants
- ASTM F2182 – Standard Test Method for Measurement of Radio Frequency Induced Heating Near Passive Implants During Magnetic Resonance Imaging
- ASTM F2213 – Standard Test Method for Measurement of Magnetically Induced Torque on Medical Devices in the Magnetic Resonance Environment
- ASTM F2503 – Standard Practice for Marking Medical Devices and Other Items for Safety in the Magnetic Resonance Environment
- ISO/TS 10974:2012 – Assessment of The Safety of Magnetic Resonance Imaging for Patients With an Active Implantable Medical Device
Medical Devices of Interest for Interaction with Magnetic Resonance
- Neurointerventional devices: aneurysm clips and coils, hydrocephalus valves/shunts, neurostimulators
- Vascular implants: stents, valves, filters
- Interventional instruments: catheters, guidewires, endoscopes
- Orthopaedic/spinal devices: joint prostheses, fracture fixation hardware, fusion and deformity constructs
- Medical monitoring and support equipment: ventilators, drug pumps
- Electrophysiology devices: pacemakers, implantable cardioverter defibrillators
- Others: handheld surgical instruments, implantable (cochlear) hearing devices