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 Beyond the brim, Sombrero Galaxy's halo suggests turbulent past
21.02.2020 | NASA/Goddard Space Flight Center

nachricht 10,000 times faster calculations of many-body quantum dynamics possible
21.02.2020 | Christian-Albrechts-Universität zu Kiel

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: A step towards controlling spin-dependent petahertz electronics by material defects

The operational speed of semiconductors in various electronic and optoelectronic devices is limited to several gigahertz (a billion oscillations per second). This constrains the upper limit of the operational speed of computing. Now researchers from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg, Germany, and the Indian Institute of Technology in Bombay have explained how these processes can be sped up through the use of light waves and defected solid materials.

Light waves perform several hundred trillion oscillations per second. Hence, it is natural to envision employing light oscillations to drive the electronic...

Im Focus: Freiburg researcher investigate the origins of surface texture

Most natural and artificial surfaces are rough: metals and even glasses that appear smooth to the naked eye can look like jagged mountain ranges under the microscope. There is currently no uniform theory about the origin of this roughness despite it being observed on all scales, from the atomic to the tectonic. Scientists suspect that the rough surface is formed by irreversible plastic deformation that occurs in many processes of mechanical machining of components such as milling.

Prof. Dr. Lars Pastewka from the Simulation group at the Department of Microsystems Engineering at the University of Freiburg and his team have simulated such...

Im Focus: Skyrmions like it hot: Spin structures are controllable even at high temperatures

Investigation of the temperature dependence of the skyrmion Hall effect reveals further insights into possible new data storage devices

The joint research project of Johannes Gutenberg University Mainz (JGU) and the Massachusetts Institute of Technology (MIT) that had previously demonstrated...

Im Focus: Making the internet more energy efficient through systemic optimization

Researchers at Chalmers University of Technology, Sweden, recently completed a 5-year research project looking at how to make fibre optic communications systems more energy efficient. Among their proposals are smart, error-correcting data chip circuits, which they refined to be 10 times less energy consumptive. The project has yielded several scientific articles, in publications including Nature Communications.

Streaming films and music, scrolling through social media, and using cloud-based storage services are everyday activities now.

Im Focus: New synthesis methods enhance 3D chemical space for drug discovery

After helping develop a new approach for organic synthesis -- carbon-hydrogen functionalization -- scientists at Emory University are now showing how this approach may apply to drug discovery. Nature Catalysis published their most recent work -- a streamlined process for making a three-dimensional scaffold of keen interest to the pharmaceutical industry.

"Our tools open up whole new chemical space for potential drug targets," says Huw Davies, Emory professor of organic chemistry and senior author of the paper.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

70th Lindau Nobel Laureate Meeting: Around 70 Laureates set to meet with young scientists from approx. 100 countries

12.02.2020 | Event News

11th Advanced Battery Power Conference, March 24-25, 2020 in Münster/Germany

16.01.2020 | Event News

Laser Colloquium Hydrogen LKH2: fast and reliable fuel cell manufacturing

15.01.2020 | Event News

 
Latest News

Active droplets

21.02.2020 | Medical Engineering

Finding new clues to brain cancer treatment

21.02.2020 | Health and Medicine

Beyond the brim, Sombrero Galaxy's halo suggests turbulent past

21.02.2020 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>