Magnetic resonance: Back to the future

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Nuclear magnetic resonance (NMR) is a powerful research tool based on the detection of electromagnetic signals that emanate from the nuclei of certain atoms. The method is quite analogous to the way radio works: the atoms are the radio stations emitting signals, while the researcher, in turn, is the listener who tunes their radio to the station of choice. What is so special about NMR, however, is that the frequency of the signals coming from the atoms are uniquely linked to the local environment in which they are situated. As such, these signals provide very precise information about a wide variety of physical, chemical, biological, and material properties. For example, the NMR signal from the hydrogen atoms in our bodies can be detected non-invasively and used to locate and diagnose injury or disease. This technique, known as magnetic resonance imaging (MRI), is one of the most important tools in modern medicine. NMR has been in use since the 1950s, and MRI since the 1970s. Both techniques have advanced immensely since those times, with innovation largely being driven by a "bigger-is-better" approach, in which stronger and stronger magnetic fields have been employed. Anyone who has ever had an MRI scan can attest to the size of the apparatus, which is in fact a large cylindrical magnet with a central bore for the patient. This same cylindrical magnet design is used for almost all research systems as well, and a "one-style-fits-all" strategy has dominated NMR/MRI for decades. There are many good reasons to buck both these trends, however, and to explore new application-specific designs that offer greater functionality to a broader range of users. One example is the potential for lighter, cheaper MRI scanners operating at lower magnetic field. They may not produce as high a quality image as large clinical scanners, but they could be portable and provide excellent point-of-care imaging for specific situations, or be used in small or remote communities where MRI technology is otherwise unavailable. In many ways, this approach is like going way back in time to when magnetic resonance was performed in much lower fields and with much simpler apparatus. Much has changed since the early days of NMR/MRI, however, and this time around new technology and a broader range of potential applications will fuel an era of innovation that will not end up on the old path of bigger-is-better and one-style-fits-all. As a result, the future of magnetic resonance might just be "smaller, lighter, and smarter." The goal of my research program is to advance the performance and widespread use of magnetic resonance technology. I will focus on the development of new application-specific hardware and techniques for low-field NMR/MRI, in particular a method known as gradient-free imaging, which lends itself to more versatile apparatus. Potential applications range from health care (e.g. point-of-care medical imaging) to agriculture (e.g. evaluating grain quality).