Design and Experimental Assessment of a 2D Microwave Imaging System for Brain Stroke Monitoring

Abstract

The aim of this paper is to present and experimentally verify the first prototype of a microwave imaging system specifically designed and realized for the continuous monitoring of patients affected by brain stroke, immediately after its onset and diagnosis. The device is a 2D version of the 3D system, currently under construction, and consists of an array of 12 printed monopole antennas connected to a two-port vector network analyzer through a switching matrix so that each antenna can act as a transmitter or receiver, thereby allowing the acquisition of the entire multistatic multiview scattering matrix required for the imaging. The system has been experimentally tested on 2D phantoms with electric properties mimicking the brain. The presence and the evolution of the stroke have been reproduced by filling a proper cavity in the phantom with a liquid having the electric properties of blood. A differential approach has been adopted by acquiring the scattering matrix before and after the filling of the blood cavity. The so achieved differential dataset has been processed by means of a linear imaging algorithm in order to reconstruct the stroke location and dimension. Moreover, the effect of pre- and postprocessing operations on the measured data is investigated. A good agreement has been obtained between the reconstructions and the actual scenario. As a final remark, it is worth noting that the entire data acquisition and processing are sufficiently fast to allow a real-time monitoring.

Experimental Validation of Microwave Tomography with the DBIM-TwIST Algorithm for Brain Stroke Detection and Classification

“…While there are a few experimental studies on detecting a blood-like target using microwave imaging methods [15][16][17]44,45], only a few studies exist that demonstrate experimentally the detection of an ischemic-like area. Our results in this respect are encouraging, as they indicate that a classification of the stroke type is possible with a microwave imaging system without the need of training data [18].…”

“…Efforts to develop MWI systems for medical diagnostics go back almost forty years, with several review papers, book chapters, and special issues reporting recent developments [5][6][7]. Amongst a large body of research in medical microwave imaging, which cannot possibly be fully reviewed here, we note that various experimental systems have been developed for breast cancer detection [8][9][10][11][12][13][14], and more recently for stroke monitoring and detection [15][16][17]. Prototypes based on machine learning have also been developed and clinically tested [18].…”

A Grounded Coplanar Waveguide-Based Slotted Inverted Delta-Shaped Wideband Antenna for Microwave Head Imaging

“…With respect to microwave imaging features, scholars have been proposed numerous categories of antenna for head imaging platforms. For instance, tapered slot antenna [7], triangle patch microstrip antenna [16], ultrawideband (UWB) slot antenna [17], electromagnetic band gap (EBG) based antenna [18], slotted T-shaped antenna [19], printed monopole [20], flexible monopole [6], different types of UWB array antenna [21][22][23], directional monopole antenna [6], various categories of antipodal Vivaldi antenna [24][25][26][27], various categories Vivaldi antennas [28,29], wideband textile antenna [30], conformal antenna [31], bowtie antenna [32], wideband monopole antenna [33], different types of 3D antenna such as slot-loaded wideband antenna [14], stacked 3D folded antennas [34,35], slot-loaded folded dipole antenna [36]. In the current microwave head imaging applications stage, it is essential to design comparatively small size antennas with wideband, high gain, directional radiation capability, higher bandwidth, and efficiency.…”

Image Improvement Through Metamaterial Technology for Brain Stroke Detection

“…Thus, compact antennas operating below 1.5 GHz immersed in a coupling medium are used [4]. Structures such as helmet or chambers, allow the use of a lossy dielectric medium for the operating antennas [5], [6]. Nevertheless, the success of a MWT device depends on the hardware characteristics in conjunction with a strong and robust imaging algorithm.…”