A numerical study concerning brain stroke detection by microwave imaging systems

Abstract

In this paper, a numerical study devoted to evaluate the application of a microwave imaging method for brain stroke detection is described. First of all, suitable operating conditions for the imaging system are defined by solving the forward electromagnetic scattering problem with respect to simplified configurations and analyzing the interactions between an illuminating electromagnetic wave at microwave frequencies and the biological tissues inside the head. Then, preliminary inversion results are obtained by applying an imaging procedure based on an iterative Gauss-Newton scheme to a realistic model of the human head. The proposed imaging algorithm is able to deal with the nonlinear and ill-posed problem associated to the integral equations describing the inverse scattering problem. The aim of the inversion procedure is related to the determination of the presence of a hemorrhagic brain stroke by retrieving the distributions of the dielectric parameters of the human tissues inside a slice of the head model

Microwave Imaging by Means of Lebesgue-Space Inversion: An Overview

“…Consequently, proper inversion procedures need to be devised, to consider both these theoretical problems. To this end, several approaches have been proposed in the last years [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. They have been investigated in the context of Hilbert spaces, in most cases.…”

Finite-element analysis of microwave scattering from a three-dimensional human head model for brain stroke detection

“…However, in this study the incorporated frequency-dependent closed-form models are evaluated at 1 GHz only. This is because 1 GHz is the most appropriate frequency for a MW head-imaging system, suggested by the previously referenced literature [ 14 , 23 , 25 , 27 , 35 , 38 , 40 , 42 ] and the evaluations we made during our research [ 43 – 45 ]. This frequency allows a good penetration of MW signals into a human head, while providing a reasonable spatial resolution of brain images.…”

“…We also performed a careful analysis of the frequency range (0.5–2.0 GHz) defined in the literature for MW head-imaging applications [ 14 , 17 , 23 , 40 ]. Initially, we conducted our simulations on simpler head models with frequency-dispersive dielectric properties of brain tissues.…”

“…In 2017, Bisio et al [ 40 ] implemented an MoM–iterative Gauss-Newton scheme to evaluate the performance of MWT for haemorrhagic stroke detection in a 2D head slice. The authors also investigated the suitable operating conditions for a MWI system and the effects of background medium permittivity on image reconstruction results.…”

Microwave Imaging of 3D Dielectric Structures by Means of a Newton-CG Method in lp Spaces

“…The common aspect of such iterative techniques is that the original nonlinear problem is firstly linearized around the current solution estimate and then approximately solved by means of a linear regularization method. For their attractive features, Newton-based techniques have been chosen and specialized for different applications, ranging from the detection of buried objects [20,21] and the imaging of civil structures and wood [19] to the biomedical uses for breast imaging [22,23] and brain stroke detection [24].…”