Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

High-resolution MRI imaging inspired by the humble antenna

01.11.2018

High-resolution magnetic resonance imaging (MRI) machines can work better by changing the structure of radio probes from coils to antennas.

How can you make a high-frequency MRI machine more precise? By taking an electrical engineering approach to creating a better, uniform magnetic field.


Proposed radio frequency probes to create homogeneous magnetic field within a phantom under study: single multi dielectric patch surface probe (upper left), volume probe composed of two vis-à-vis placed dielectric patch probes (lower left), volume probe composed of two cylindrical patches (upper right) and cosine-profiled patches (lower right).

Credit: Navid P. Gandji

In a new study published in Transactions on Microwave Theory and Techniques, researchers have discovered that radio frequency probes with structures inspired by microstrip patch antennas increase MRI resolution in high-frequency MRI machines, when compared to conventional surface coils used now.

"When frequencies become higher, wavelengths become shorter, and your magnetic field loses uniformity," says Elena Semouchkina, an associate professor of electrical and computer engineering at Michigan Tech. "Uniformity is important for high resolution images, so we proposed a new approach to developing these probes."

Semouchkina explains that kind of antenna that you see on the top of a building isn't quite the same thing used here, but instead, the team's design was inspired by microstrip patch antenna (MPA). The design is relatively simple: MPAs are made of a flat piece of metal grounded by a larger piece of metal. They're cheap, simple, and easy to make, which is why they're so often used in telecommunications.

MRIs work by issuing radio frequency pulses in a magnetic field via probes with coils or bird-cage like structures. That's then used to create an image.

But those conventional coils have frequency limits: too high and they can't create uniformed magnetic fields at the volume researchers need.

MPAs are an alternative where waves oscillate in the cavity formed between the patch and ground plane electrodes, which are accompanied by currents in the patch electrode and, respectively, oscillating magnetic fields around the patch, providing a magnetic field that is both even and strong.

"While the complexity of birdcage coils increases with the increase in operation frequency, patch-based probes can provide quality performance in the higher microwave range while still having a relatively simple structure," Semouchkina says. They also showed smaller radiation losses, making them competitive with, even better, than conventional coils.

Because of the damage high-frequency radio waves cause to humans, the study was limited to high frequency machines--not the metal tube that we're used to seeing in hospitals and medical centers. Humans 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 in tissue samples.

Semouchkina is already known for her work involving invisibility cloaks, which involve redirecting electromagnetic waves around an area to hide an object. "We use some of the same approaches that we developed in cloaking devices here, like making antenna smaller," she said.

###

This study was conducted with Navid P. Gandji and George Semouchkin of Michigan Tech and Gangchea Lee, Thomas Neubereger and Micheal Lanagan of Pennsylvnia State University. The team's next step is to keep applying electrical engineering to modify those probes to make them work better, and to further expand the possibilities for high-frequency MRI machines, and the images they create.

Allison Mills | EurekAlert!
Further information:
https://www.mtu.edu/news/stories/2018/october/updating-highresolution-mri.html
http://dx.doi.org/10.1109/TMTT.2018.2874266

More articles from Physics and Astronomy:

nachricht Electrochemistry to benefit photonics: Nanotubes can control laser pulses
11.10.2019 | Skolkovo Institute of Science and Technology (Skoltech)

nachricht Radiation detector with the lowest noise in the world boosts quantum work
11.10.2019 | Aalto University

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Controlling superconducting regions within an exotic metal

Superconductivity has fascinated scientists for many years since it offers the potential to revolutionize current technologies. Materials only become superconductors - meaning that electrons can travel in them with no resistance - at very low temperatures. These days, this unique zero resistance superconductivity is commonly found in a number of technologies, such as magnetic resonance imaging (MRI).

Future technologies, however, will harness the total synchrony of electronic behavior in superconductors - a property called the phase. There is currently a...

Im Focus: How Do the Strongest Magnets in the Universe Form?

How do some neutron stars become the strongest magnets in the Universe? A German-British team of astrophysicists has found a possible answer to the question of how these so-called magnetars form. Researchers from Heidelberg, Garching, and Oxford used large computer simulations to demonstrate how the merger of two stars creates strong magnetic fields. If such stars explode in supernovae, magnetars could result.

How Do the Strongest Magnets in the Universe Form?

Im Focus: Liquifying a rocky exoplanet

A hot, molten Earth would be around 5% larger than its solid counterpart. This is the result of a study led by researchers at the University of Bern. The difference between molten and solid rocky planets is important for the search of Earth-like worlds beyond our Solar System and the understanding of Earth itself.

Rocky exoplanets that are around Earth-size are comparatively small, which makes them incredibly difficult to detect and characterise using telescopes. What...

Im Focus: Axion particle spotted in solid-state crystal

Scientists at the Max Planck Institute for Chemical Physics of Solids in Dresden, Princeton University, the University of Illinois at Urbana-Champaign, and the University of the Chinese Academy of Sciences have spotted a famously elusive particle: The axion – first predicted 42 years ago as an elementary particle in extensions of the standard model of particle physics.

The team found signatures of axion particles composed of Weyl-type electrons (Weyl fermions) in the correlated Weyl semimetal (TaSe₄)₂I. At room temperature,...

Im Focus: A cosmic pretzel

Twin baby stars grow amongst a twisting network of gas and dust

The two baby stars were found in the [BHB2007] 11 system - the youngest member of a small stellar cluster in the Barnard 59 dark nebula, which is part of the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Symposium on Functional Materials for Electrolysis, Fuel Cells and Metal-Air Batteries

02.10.2019 | Event News

NEXUS 2020: Relationships Between Architecture and Mathematics

02.10.2019 | Event News

Optical Technologies: International Symposium „Future Optics“ in Hannover

19.09.2019 | Event News

 
Latest News

Electrochemistry to benefit photonics: Nanotubes can control laser pulses

11.10.2019 | Physics and Astronomy

Biologically inspired skin improves robots' sensory abilities (Video)

11.10.2019 | Power and Electrical Engineering

New electrolyte stops rapid performance decline of next-generation lithium battery

11.10.2019 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>