MRI Redesign Could Improve User Experience

Pruessmann Figure 1-Mechanics of both approaches BC

An antenna interacts with the sample via a travelling electromagnetic wave. Its magnetic component B excites nuclear oscillations and receives the resonance signals. Image credit: Swiss Federal Institute of Technology Zurich.

Patients suffering from claustrophobia rejoice: a new MRI design may enable a more-comfortable user experience.Conventional MRI designs rely on near-field coupling, which requires that the detector is as close to the subject as possible, hence the narrow claustrophobia-inducing tube. MRI scanners also employ stationary radiofrequency fields to excite magnetic resonance in hydrogen nuclei in order to obtain the desired image. However, a team of Swiss researchers has developed a new approach to capturing images that has radiofrequency waves on the move.Rather than using stationary radiofrequency fields for MRI, the Swiss scientists adopted the use of traveling radiofrequency waves. A magnet lined with a conductive material served as a suitable waveguide for efficient signal transmission while an antenna generated propagating waves that penetrated the imaging sample and recorded resonance signals. This method produced magnetic resonance images of larger parts of the body more uniformly than was previously possible, according to the team. Furthermore, the technique enabled signal reception across distances in the meter range, which would allow for more-spacious MRI designs."The fact that MRI signals can be received with an antenna and across such large distances is remarkable; it‘s a paradigm shift," says Klaas Prüssmann, a professor at the Institute of Biomedical Engineering of the ETH Zurich and one of the researchers. He adds, however, that despite the progress, there are still hurdles to clear before the new imaging method could be having MRI patients breathing easier. "Unfortunately, the cost of the strong magnets is still substantial and the clinical benefits of very high fields first need to be proven in extensive studies," he says.