Magnetic Resonance Systems Development

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The problem we are addressing is easy enough to understand: many people need permanently or semi-permanently implanted medical devices (e.g. pacemakers), and many of these people will need an MR scan at some point in their lives. Because most standard medical devices either cease to operate within an MRI system or present a danger to the subject when within the MR environment, these people will not be eligible to receive an MRI. This effectively results in a lower standard of care for subjects with implanted medical devices. The federal government and the provinces have made massive investments in medical imaging infrastructure, particularly in MRI. But these past MRI investments, exceeding $150 million, have not translated into a clear advantage for the medical device industry. This is due to the fact that MR-compatible medical device development is a highly complex problem whose solution requires access to a dedicated facility and appropriate expertise, which is currently absent in Canada. This project ultimately aims to improve the lives of Canadians by facilitating the development of safer, more advanced medical devices for use within safer, more advanced MRI systems. The MR environment is especially challenging for medical devices for several reasons. The electromagnetic environment is both highly complex and extreme. Static magnetic fields thousands of times stronger than Earth’s magnetic field are present. Spatial gradients of the static magnetic fields result in massive forces and torques on even slightly magnetic materials and objects. Strong time-varying (kHz, or “audio frequency”) gradient fields result in heating of conductive devices, electromagnetic interference, and kHz mechanical vibrations and torques. Finally, the radiofrequency (RF) electric and magnetic fields are much more intense than anything humans or devices are normally exposed to. Exposure to RF fields primarily results in significant device heating. RF electromagnetic interference can also be a problem in control and communication circuits. We are proposing to establish a comprehensive program for the research and development of MR-compatible medical devices and MR technology more generally. We already have an unrivaled installation of MR scanners, across all relevant field strengths (from the dominant clinical field strengths of 1.5T and 3T, to the emerging 7T systems for human use, of which we have the only installation in the country). In order for us to be a comprehensive “one-stop-shop” for development and testing of MR-compatible medical devices and technology, we need the additional specialized capacity to: (1) recreate those aspects of the MR system that are hypothesized to affect any given medical device, but under the controlled, reproducible conditions of the laboratory; (2) make careful, reproducible measurements of device operation and reaction to these laboratory exposure environments; (3) validate the results in the actual MR systems of importance. In this application we are proposing to train 6 graduate students and 10 undergraduates in the general area of magnetic resonance imaging, and more specifically in the areas of MR systems development and MR compatible medical device development.