Researchers from the Michigan Technological University made high-frequency MRIs more precise by creating a better, more uniform magnetic field. Radio frequency probes with structures inspired by microstrip patch antennas (MPA) can increase the MRI resolution in high-frequency MRI machines, when compared to the conventional surface coils that are commonly used now, according to the team.
“When frequencies become higher, wavelengths become shorter, and your magnetic field loses uniformity,” said Elena Semouchkina, professor at Michigan Technological University. “Uniformity is important for high-resolution images, so we proposed a new approach to developing these probes.”
MPAs, which are often used in telecommunication applications, are made of a flat piece of metal grounded by a larger piece of metal. These antennas are inexpensive and simple to produce.
MRIs work by issuing radio frequency pulses in a magnetic field through probes with coils that are used to create an image. However, these conventional coils have frequency limits; too high a frequency prevents them from creating uniformed magnetic fields at the volume needed.
High-frequency radio waves can often cause damage to humans, limiting the researchers to examine high frequency machines and not the metal tube that is seen in hospitals and other medical centers. Human can only sustain frequencies up to seven Teslas, but ultrahigh fields up to 21.1 Teslas can be used in testing on animal models and tissue samples.