A team of researchers from Germany has achieved a significant advance in medical imaging by redesigning a critical piece of MRI hardware using metamaterials — engineered structures that interact with electromagnetic waves in ways not found in nature. The innovation produces sharper images of the brain and eye in less time and can be integrated into existing MRI systems rather than requiring entirely new machines.
Published in the journal Advanced Materials, the study was led by Nandita Saha and Professor Thoralf Niendorf at the Max Delbrück Center's Experimental Ultrahigh Field Magnetic Resonance laboratory, in collaboration with clinicians at Rostock University Medical Center.
The problem with conventional MRI
MRI scanners create images by sending radiofrequency (RF) signals into the body while a powerful magnetic field is applied. Traditional MRI antennas — called RF coils — often struggle to collect sufficient signal from tissues located deep inside the body or in anatomically complex regions. The result is that image quality can suffer, and scanning sessions may take longer.
Deep brain structures and the delicate tissues of the eye and surrounding orbit are especially challenging. The eye, in particular, is difficult to image with MRI because of its small size and the complex anatomy of the orbit.
How metamaterials change the game
The researchers incorporated metamaterials directly into the MRI antenna. Metamaterials are artificially structured materials that can manipulate electromagnetic fields in precise ways. In testing, the new antenna strengthened signals from targeted tissues, increased spatial resolution, improved image sharpness, and accelerated data collection.
By using concepts from metamaterials, we were able to guide radiofrequency fields more efficiently and demonstrate how advanced physics can directly improve medical imaging, said Niendorf, senior author of the paper. This work shows a pathway toward faster, clearer MRI scans that could benefit patients in many clinical areas.
A window into the eye
The team tested the design by imaging the eye and orbit in volunteers using a 7.0 Tesla MRI scanner. The results were striking: the new antenna produced anatomically detailed, high-resolution images of structures that have been largely inaccessible to conventional MRI.
Our research demonstrates clear relevance for ophthalmological applications as it can facilitate anatomically detailed, high-spatial resolution MRI of the eye, said Professor Oliver Stachs, a co-author at University Medicine Rostock. It offers the potential to open a window into the eye and into physiological processes that in the past have been largely inaccessible.
Beyond eye imaging
The technology has potential applications far beyond ophthalmology. Researchers say it could be adapted to: - Protect sensitive parts of the body during MRI exams by reducing unwanted heating around medical implants - Improve MRI-guided cancer treatments by directing RF energy more precisely for tumor hyperthermia - Enable specialized MRI techniques that image atoms other than hydrogen, such as sodium and fluorine - Be customized for different organs, including the heart and kidneys
Because the antenna is compact and lightweight, it can potentially improve patient comfort during imaging. The design could also be adapted for MRI systems operating at different magnetic field strengths.
Next steps
The research team is now preparing larger clinical studies involving multiple hospitals. The collaboration between the Max Delbrück Center and Rostock University Medical Center will continue, with plans to modify the antenna for additional organs.
Innovations in imaging hardware have the potential to transform diagnostics, and this study is an important step toward next-generation MRI technology, said Dr. Ebba Beller, a co-author at Rostock University Medical Center.
The project was funded by the German Research Foundation (DFG) as a joint collaboration between the two institutions.
