Experimental Validation of a Microwave System for Brain Stroke 3-D Imaging

Abstract

This paper experimentally validates the capability of a microwave prototype device to localize hemorrhages and ischemias within the brain as well as proposes an innovative calibration technique based on the measured data. In the reported experiments, a 3-D human-like head phantom is considered, where the brain is represented either with a homogeneous liquid mimicking brain dielectric properties or with ex vivo calf brains. The microwave imaging (MWI) system works at 1 GHz, and it is realized with a low-complexity architecture formed by an array of twenty-four printed monopole antennas. Each antenna is embedded into the “brick” of a semi-flexible dielectric matching medium, and it is positioned conformal to the head upper part. The imaging algorithm exploits a differential approach and provides 3-D images of the brain region. It employs the singular value decomposition of the discretized scattering operator obtained via accurate numerical models. The MWI system analysis shows promising reconstruction results and extends the device validation.

Single Data Set Calibration and Imaging with Uncooperative Electromagnetic Inversion Systems

“…The installation method for antennas and connections to VNA follows the same configurations presented in Section 3.2 (e.g. [30,[39][40][41][42][43] and others) and we used the same data set that was used in [14].…”

Experimental Assessment of Real-Time Brain Stroke Monitoring via a Microwave Imaging Scanner

“…The presented work assessed a novel low-complexity scanner for brain stroke imaging dedicated to real-time pathology monitoring during the post-event treatment path. With the first generation prototype as a starting point [18], this contribution presented, first, an innovative antenna array, whose design was improved to meet portability and wearable requirements. Second, a dynamic phantom was employed to emulate stroke evolution over time, and third, an imaging algorithm, integrated with artifact removal procedures, was able to provide low noise dielectric contrast reconstructions.…”

“…The set-up is essentially composed of a static part, emulating the steady surrounding tissues, and a dynamic one, i.e., the affected area varying during the measurement. An anthropomorphic phantom is used for the head, taking as reference the one in [18]. It consists of a single-cavity 3 mm-thick container obtained through 3-D printing in clear resin (polyester casting resin), with antenna supports added externally to facilitate accurate positioning of the array.…”

“…This contribution experimentally demonstrates for the first time, to the best of our knowledge, the use of MWI for continuous real-time follow-up of both HEM and IS post-acute progressive evolution, localizing, and 3-D shaperetrieving the transition. To this end, starting from the switching mechanism in [18], a new optimized, compact, lowcomplexity radiating part of the MWI prototype is developed following the same rigorous design procedures in [19]. The prototype system consists of 22 compact and flexible antennas with custom matching mediums, collecting the multi-static multi-view scattering matrix.…”

Slotted Monopole Patch Antenna for Microwave-Based Head Imaging Applications

“…Numerous MWI devices and prototypes have been proposed recently. Among these, the Strokefinder, created by Medfield Diagnostics, and the EMTensor BrainScanner are two prominent examples (both of which are now being tested on humans) [ 2 , 4 , 9 ].…”