Magnetic resonance imaging (MRI) is one of the most valuable tools doctors use to diagnose diseases. However, even with today’s advanced scanners, it is still difficult to produce clear images of some areas. The deep structures of the brain and the delicate tissues of the eye and surrounding orbit are especially challenging due to the hardware responsible for transmitting and receiving radiofrequency signals.
Now, a team led by Nandita Saha, a PhD student in Professor Thoralf Niendorf’s ultra-high-field MRI experimental laboratory at the Max Delbrück Center, has developed a new MRI antenna based on advanced engineered materials. The innovation produces sharper images in less time and can be integrated into existing MRI systems rather than requiring entirely new machines. Their findings were published in Advanced materials.
The project brought together experts in MRI physics, clinical ophthalmology and translational imaging from the Max Delbrück Center and the Rostock University Medical Center. Rostock researchers are also helping to validate the technology for future clinical use.
“By using metamaterial concepts, we were able to guide radiofrequency fields more efficiently and demonstrate how advanced physics can directly improve medical imaging,” says Niendorf, lead author of the paper. “This work shows a path toward faster, clearer MRI scans that could benefit patients in many clinical areas.”
Metamaterials improve MRI performance
MRI scanners create images by sending radio frequency (RF) signals to the body while a powerful magnetic field is applied. As the tissues respond to those signals, the scanner gathers the information needed to generate an image. Stronger signals generally produce clearer and more detailed scans.
Traditional MRI antennas, also known as RF coils, often have trouble collecting enough signal from tissues located deep in the body or in anatomically complex regions. As a result, image quality may suffer and scanning sessions may take longer.
To overcome this limitation, the researchers incorporated metamaterials directly into the MRI antenna. Metamaterials are specially designed structures that interact with electromagnetic waves in a way that natural materials cannot. During testing, the new antenna strengthened signals from specific tissues, increased spatial resolution, improved image sharpness, and accelerated data collection.
A major advantage is that the antenna is compatible with existing MRI equipment, eliminating the need for expensive new infrastructure. The researchers tested the design by imaging the eye and orbit of volunteers using a 7.0 Tesla MRI scanner.
“Our research demonstrates clear relevance for ophthalmological applications as it can facilitate anatomically detailed and high spatial resolution MRI of the eye,” says Professor Oliver Stachs, co-author of the paper at the Medical University of Rostock. “It offers the potential to open a window to the eye and to (patho)physiological processes that have been largely inaccessible in the past.”
Potential beyond eye images
“Our goal was to rethink MRI hardware based on the modern physics of antenna design,” adds Saha.
She says the technology could also be adapted to help protect sensitive parts of the body during MRI exams by reducing unwanted heating around medical implants. Additionally, it may improve MRI-guided cancer treatments by directing RF energy more precisely for procedures such as tumor hyperthermia or thermal tissue ablation.
Faster scans and better diagnoses
MRI exams can be long and uncomfortable, especially when scans need to be repeated because it is difficult to capture important anatomical details. By producing clearer images more quickly, the new antenna could shorten scanning times and give doctors greater confidence in their diagnoses.
Because the antenna is compact and lightweight, it can also be customized for different parts of the body, potentially improving patient comfort during imaging.
Niendorf says the design could eventually be adapted for MRI systems operating at magnetic field strengths below and above 7.0 T. It could also be adapted to image organs beyond the eye, orbit and brain, or used to monitor metabolism and track how drugs move through the body.
The technology can also improve specialized MRI techniques that image atoms other than hydrogen, including sodium and fluorine, generating stronger signals and higher quality images.
“Innovations in imaging hardware have the potential to transform diagnosis, and this study is an important step towards next-generation MRI technology,” says Dr. Ebba Beller, co-author of the paper at Rostock University Medical Center.
Next steps
The research team is preparing larger clinical studies involving several hospitals while modifying the antenna for additional organs, including the heart and kidneys. The long-standing collaboration between Stachs and Niendorf will also continue through reciprocal appointments of visiting scientists.
The project was funded by the DFG as a joint collaboration between the Max Delbrück Center and the Medical University of Rostock.