Abstract
Brain stroke is one of the most common diseases worldwide, with over 15 million cases every year causing death or permanent injuries. Its treatment significantly relies on the information provided by diagnostic methodologies, as they support the clinician in the choice of the therapy and in following its effectiveness. Magnetic resonance imaging and computerized tomography (CT) are the most assessed and reliable diagnostic tools. However, they are time consuming, not portable and costly and, in the case of CT, harmful due to ionizing radiations. Therefore, they are not viable for bedside monitoring and repeated examinations.
For these reasons, there is an interest in developing complementary techniques, especially for a more effective follow-up in the post-acute stage, whose proper and timely management is crucial to improve the potential recovery of the patient.
However, there is currently a lack of an imaging apparatus able to continuously monitor a patient after the stroke onset. With the MiBraScan project, we aim to fill this gap, by developing a novel device, which will be capable of performing this task as well as to supply additional images to support the clinician in the diagnostic stage. The underlying technology is microwave imaging, which exploits the difference in dielectric properties of tissues. As a matter of fact, recent studies have demonstrated that an electric contrast exists between healthy brain tissues and those affected by ischemic or hemorrhagic stroke. In particular, we will exploit this concept to both track the evolution in time of the stroke, as well as to image (in a quantitative fashion) the features of the tissues it has affected.
The MiBraScan device will be completely non-invasive for the patient, thanks to the non-ionizing nature of microwaves and the low required electromagnetic power. Moreover, thanks to a proper design of the antennas layout and of the electronics, it will be portable and cost-effective. As such, it could be available at the patient bed for an almost continuousmonitoring and will allow the hospital to acquire several systems for multiple parallel examinations. The device will produce results (images) in real-time, by relying on ad-hoc inverse scattering based data processing techniques and their proper hardware implementation via field-programmable gate array.
The project will lead to the development of a full-scale prototype (hardware and data processing) and its full characterization and assessment by means of accurate numerical simulations and extensive experiments with 3D anthropomorphic head phantoms. As such, its successful completion will provide the background needed to approach the subsequent clinical trials, which will open the way to the expected significant advantages for the population and the sustainability and effectiveness of health systems.
Expected Results
The MiBraScan project aims to develop and build the prototype of a microwave imaging (MWI) device able to track the evolution in time of a stroke, as well as to image the features of the tissues it has affected.
To face the current lack of an imaging apparatus for bedside continuous monitoring, our goal is to realize a device for brainstroke monitoring that:
- is non-invasive and safe, thanks to the use of low-power, non ionizing radiations;
- provides real-time images of the stroke evolution, thanks to tailored processing algorithms and their hardware implementation;
- is portable at the patient bed, thanks to the use of ad-hoc developed front-end electronics;
- is cost-efficient, thanks to low-cost of the involved technologies.
If successful, the MiBraScan project will provide the first worldwide prototype based on microwave techniques able to monitor the patient during the stroke follow-up period. In addition, the MiBraScan prototype will be equipped with tailored algorithms to image (in a quantitative fashion) the brain tissues, which allows its perspective use for the diagnosis of brain stroke, and not only monitoring.
This device (seen as a whole of hardware components and data processing tools) is completely different from the (few) examples available in the literature and will be a significant leap in the development of new tools to supply the clinicians in managing strokes. Notably, being potentially low-cost, it would give the possibility to hospitals to acquire several systems for simultaneous monitoring of more patients.The developed prototype will be extensively characterized and assessed, first with accurate numerical simulations and then with experiments on 3D anthropomorphic head phantoms.
Main Targets
To realize and test the MiBraScan prototype, five main targets are planned during the project:
- EM modeling: Antenna design and layout optimization by means of an in-house 3D full-wave EM modeling tool able to accurately simulate the whole MWI system. This modeling tool will also provide the environment to assess the imaging algorithms.
- Imaging tools development: Implementation and numerical testing of MWI algorithms to monitor the evolution (shape and extent) of ischemic or hemorrhagic strokes, and to provide images of the features of the tissues that stroke has affected.
- System prototyping: Antennas realization and characterization; development of an ad-hoc radiofrequency front-end system, customized for the proposed imaging technique; accelerated implementation of the imaging algorithms with specialized hardware such as a Field Programmable Gate Array, for real-time results.
- Head phantoms generation: Generation of numerical phantoms from segmented medical images; building of realistic 3D phantoms of human head representing the evolution of a stroke.
- Proof-of-concept assessment: The built prototype will be extensively tested with the realized anthropomorphic phantoms in various experiments mimicking different stroke conditions.