Magnetic Resonance Imaging (MRI) Safety and Effectiveness
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Summary
Magnetic resonance imaging (MRI) is a widely used diagnostic modality with an excess of 30 million scans performed every year in the U.S. Although MRI is considered an exceedingly safe modality, there is an underlying potential for injury to patients due to the strong electromagnetic (EM) fields used in MR scanning. In addition, the rapid increase in the number of patients with medical implants who require MRI scans has spawned a new focus in the field of MRI safety, due to the interactions of medical implants with EM fields used during MR scanning. As a result, this has led to an increase in premarket submissions for medical devices that are compatible with the MR environment.
This research area mainly centers on understanding the safety aspects of medical implants and some aspects of MRI applications. Here are some of regulatory science areas covered by this group::
- Development of underlying tools for studying interactions leading to thermal injury by electromagnetic modeling, laboratory measurements, and thermometry
- Retrospective evaluation and comparison of testing data to understand trends and effects of passive implants
- Testing of selected devices in an MRI environment to gain further insights or guide policy (e.g. stents, devices with magnets)
- Studying the physiological responses of thermal dosing (Brain perfusion imaging)
- Standardizing MRI methods for screening of silicone breast implants
3D view of the computational model of a radiofrequency (RF) coil system at 64 MHz used in magnetic resonance imaging (MRI). Computational modeling of coils is extensively used in the evaluation of RF-induced heating during MRI.
3D view of the physical radiofrequency (RF) coil system at 64 MHz used in magnetic resonance imaging (MRI) available in our laboratory.
Testing of stents at the bench and in computational modeling for RF exposure during MRI.
This group supports the agency's regulatory and guidance role by advancing knowledge on the complex interactions between electromagnetic fields and human body. These projects are conducted with active collaborations with researchers within the FDA as well as at leading academic research institutes and industry organizations worldwide. Research is funded by internal (Office of Women's Health) and external (CRADA) support. Additionally, we are currently leading the Medical Device Innovation Consortium (MDIC) working group on Computational Modeling and Simulations – RF heating in MRI.
Current funding sources
FDA Office of Women's Health
Cooperative Research and Development Agreement (CRADA), Imricor Inc.
Personnel
FDA Staff:
Sunder Rajan, Ph.D.
Howard Bassen
Kyoko Fujimoto, Ph.D.
Wolfgang Kainz, Ph.D.
David Soltysik, Ph.D.
External collaborators
- ANSYS Inc.
- Imricor Medical Systems
- IT'IS Foundation, Zurich, Switzerland
- Massachusetts General Hospital, Harvard Medical School
- Max Plank Institute, Leipzig, Germany
- Medical Device Innovation Consortium
- Northwestern University
- University of Houston
Resource facilities
- Gradient coil simulator with amplifiers (MRCOMP, Germany)
- MITS1.5 and MITS3.0: RF coils at 64MHz and 128MHz
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(ZMT Zurich MedTech AG, Zurich, Switzerland) - DASY52 AIMD Scanner: robotic measurement system (SPEAG, Zurich, Switzerland)
- Electromagnetic and thermal solvers:
- Fluoroptic Thermometer
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Relevant standards & guidance
- Establishing Safety and Compatibility of Passive Implants in the Magnetic Resonance (MR) Environment - Guidance for Industry and Food and Drug Administration Staff
- Criteria for Significant Risk Investigations of Magnetic Resonance Diagnostic Devices - Guidance for Industry and Food and Drug Administration Staff
Selected peer review publications
- Fujimoto K et al. Radio-Frequency Safety Assessment of Stents in Blood Vessels During Magnetic Resonance Imaging. Frontier in Physiology. 2018
- Kozlov et al. Lead Electromagnetic Model to Evaluate RF-Induced Heating of a Coax Lead: A Numerical Case Study at 128 MHz. IEEE J Electromagn RF Microw Med Biol. 2018.
- Song et al. Retrospective analysis of RF heating measurements of passive medical implants. Magnetic Resonance in Medicine. 2018
- Lucano E et al. A numerical investigation on the effect of RF coil feed variability on global and local electromagnetic field exposure in human body models at 64 MHz. Magnetic Resonance in Medicine. 2017
- Lucano et al. Assessing the electromagnetic field generated by a radiofrequency body coil at 64 MHz: defeaturing vs. accuracy. IEEE Trans Biomed Eng. 2016.
- Tovar et al. A Rotational Cylindrical fMRI Phantom for Image Quality Control. Plos One, 2015
- Serano et al., A Novel Brain Stimulation Technology Provides Compatibility with MRI. Scientific Reports, 2015.
- Iacono et al., MIDA: A Multimodal Imaging-Based Detailed Anatomical Model of the Human Head and Neck, PLoS ONE 2015.
- Iacono et al. MRI-based multi-scale model for electromagnetic analysis in human head with implanted DBS. Computational and Mathematical Methods in Medicine, 2013.
- Park et al., A novel method to decrease electric field and SAR using an external high dielectric sleeve at 3 T head MRI: numerical and experimental results, IEEE Trans Biomed Eng. 2015.
- Rajan et al., A dialyzer-based flow system for validating dynamic contrast enhanced MR image acquisition, Magnetic Resonance in Medicine, 2014.
- Murbach et al., Whole-Body and Local RF Absorption in Human Models as a Function of Anatomy and Position within 1.5T MR Body Coil, Magnetic Resonance in Medicine, 2014.
- Liu et al., Computational and experimental studies of an orthopedic implant: MRI-related heating at 1.5-T/64-MHz and 3-T/128-MHz. Journal of Magnetic Resonance Imaging, 2013.