por Gus Iversen
, Editor in Chief | November 04, 2019
Researchers at ITMO University in Saint Petersburg have developed a new preclinical MR coil that produces images at three times the resolution of standard commercial volume MR coils. Using inexpensive materials and manufacturing technology, they have created the component and have captured high-resolution, whole-body imagery of a mouse.
We spoke to Anna Hurshkainen, one of the researchers and an engineer in the department of nanophotonics and metamaterials at ITMO University to find out more about the coil and the importance of increasing preclinical imaging capabilities.
HCB News: We often think of preclinical testing as an early step toward introducing a new capability to clinical care. In the case of your coils, is it fair to say that you're providing a way to improve the quality of preclinical testing?
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In our research, we apply solutions and ideas from radio physics to both MR preclinical and clinical applications. Most of our colleagues are radio physics specialists but we also have nuclear magnetic resonance (NMR) physicists in our group. This tight contact of the specialists in these two areas allows finding the solutions of radio physics which can help to improve the quality of both preclinical and clinical imaging. We are also in close contact with biophysics and clinical doctors who also help us to determine relevant clinical and preclinical tasks.
HCB News: Can you provide some examples where a better MR coil might yield more useful insights from preclinical testing?
To our knowledge, there is a relevant task of preclinical MR — whole-body small animal imaging. Biomedical specialists are interested in the imaging of the animal (mouse, for instance) to see the whole vessel structure or to observe the delivery of the drug marked by an MR-visible marker. We developed the special coil which is optimal for this exact application: it provides optimal signal-to-noise ratio of the whole mouse image which can be obtained in a short time.
HCB News: I understand that your coils comprise inexpensive materials. Can you tell us more about that?
To build our coils we need easily accessible low-cost materials. Usually we use printed circuit boards, which we design by ourselves. Also, the workhorse of all our prototypes is a simple, thin copper or brass tube which can be bought in a supermarket. Conventional preclinical MR coils usually contain a set of expensive, hard-to-get, tunable, non-magnetic capacitors. We don't need them, since our coils usually use the principle of distributed or constructive capacity and inductance; we use mechanical adjustment to tune our coils.
HCB News: How do these coils compare with conventional MR coils? Do you think the design of your coils could impact the way we think of and develop coils in general?
In our coils, we use the recently developed principle of using the periodical electromagnetic structures — metamaterials — to improve MR visualization. Metamaterials are of interest in electromagnetics as structures capable of electromagnetic field behavior manipulation. Since all MR scanners use the radiofrequency antennas — MR coils — to emit and receive the signal used to make an image, we can use metamaterials to manipulate the fields created by these antennas. We believe that this novel approach for building the coils can have an impact on the general coil development, since it provides simple and variable solutions for the near field manipulation and, thus, building the targeted coils for certain clinical and preclinical applications.
HCB News: As you move toward more clinical applications, will whole-body imaging continue to be the focus? If so, what advantages does whole-body imaging provide?
Among our research activities, there is one related to the development of the whole-body coil for a 1.5 Tesla clinical scanner equipped with a radiofrequency shield of a special type. Conventional transmit coils of clinical scanners, so-called “birdcage”, are usually equipped with a metal shield which reduces its efficiency. Our approach is using an artificial periodic structure instead of a conventional metal shield, which can improve the transmit efficiency of the coil. We believe that this will provide new possibilities in whole-body human imaging.
HCB News: What are some of the primary challenges with bringing this approach to coil technology to human applications?
Development of preclinical coils is not as challenging as clinical ones, since the latter are under strict regulations, related to in vivo testing of these coils on the research level. Testing of preclinical coils usually can be done in a short time after the development and manufacturing. Moreover, new ideas are embedding in the clinical coils market reluctantly and slowly. Most vendors, the coils of which are used in clinics in the vast majority of cases, use solutions proven over the years. Nevertheless, we work on the development of clinical coils and currently prepare all the required documents related to safety aspects within our commercialization strategy and embedding of our coil to clinical practice.
HCB News: Can you tell us what the next steps are in your efforts to validate and build upon your research?
This question corresponds to the previous one: currently, we are working intensively on a commercialization strategy. The goal is to implement developed solutions based on our scientific research both in clinical and preclinical practice. Our research activities related to the development of metamaterial-based coil is also an ongoing process — we have a lot of ideas and an enthusiastic team for their realization. We also have a big project related to the development of MR solutions based on ceramic materials, which are manufactured here in Saint-Petersburg and have unique electromagnetic properties. This approach has already shown excellent results in MR microscopy.