National Research University of Information Technologies, Mechanics and Optics ITMO University, St. Petersburg, Russia
http://en.ifmo.ru/en/

A collaboration of researchers from Russia, Australia, and the Netherlands have developed a technology that can reduce magnetic resonance imaging (MRI) scanning times by more than 50 percent, meaning hospitals can drastically increase the number of scans without changing equipment. This extraordinary leap in efficiency, they explained, is achieved by placing a layer of metamaterials onto the bed of the scanner, which improves the signal-to-noise ratio.

Fig. 1 – A typical MRI scan can take 15 to 60 minutes, while a scan using metamaterials may take half that time.

MRI is a key method of modern diagnostics. However, its effectiveness depends almost entirely on the quality of resulting MRI images.

Scientists from Russia’s ITMO University, the Australian National University, Ioffe Physical-Technical Institute, University Medical Center Utrecht, and the Institute of Experimental Medicine, demonstrated that the quality of MRI images could be substantially increased through the use of metamaterials, which are artificial periodic structures that can interact with electromagnetic radiation in an extraordinary fashion.

“This is the first real demonstration of the practical potential of metamaterials for MRI imaging enhancement and scanning time reduction. Our research may evolve into new healthcare applications and commercial products,” said Yuri Kivshar, head of the Nonlinear Physics Centre at the Australian National University.

How It Works

By placing a specially designed metamaterial under the studied object in an MRI scanner, it is possible to increase the signalto- noise ratio in the scanned area. The result of this increase is that either a higher resolution image can be obtained over the same time slot or faster examination can be performed with the same resolution as in an ordinary MRI scanner. In addition, the metamaterial suppresses the electric field, which is responsible for tissue heating—a phenomenon that may compromise the safety of the whole MRI procedure.

The problem of tissue heating has recently become even more relevant with the arrival of high-field and ultrahigh- field MRI scanners in the medical practice. A drive for high-field MRI is mediated by the benefits of better image resolution However, tissue heating becomes substantial at higher fields due to an increase of the radiofrequency energy absorption. Therefore, the issue of safety in high-field and ultra-highfield MRI scanners remains open.

The scientific group managed to entirely avoid tissue heating, at the same time preserving high resolution. The solution, in essence, does not require any intervention into the hardware of the MRI scanner, but rather represents an inexpensive functional add-on device that can be used with any existing MRI scanner.

“Our metamaterial can be embedded directly into the patient table of any commercially available MRI scanner. However, in the future we see even more potential in the concept of special smart clothing for MRI scanning,” explained Alexey Slobozhanyuk, a researcher at International Laboratory of Applied Radiophysics.

They stated that strips of the metamaterial can be sewn into clothes worn by patients undergoing the scans, which would lead to higher resolution MRI images. And, the special design will enable a homogeneous enhancement of the signal-to-noise ratio, which does not pose any risk to the patient’s health. As a result, the metamaterials can improve the characteristics of low-field MRI to the extent that their functionality is comparable to high-field MRI.

In ordinary MRI devices, the scan may last from 15 to 60 minutes and, during this time, the patient must remain completely immovable. The possibility of achieving detailed images in a shorter time slot will make the procedure more comfortable for the patient and in the long view could even reduce wait time in hospitals. (See Figure 1)

The patent-pending technology is currently being co-developed by MediWise, a UK-based company that specializes in commercializing metamaterials for medical applications.