Full-Vectorial Parallel Finite-Element Contrast Source Inversion Method

Zakaria, Amer; Jeffrey, Ian; LoVetri, Joe

doi:10.2528/pier13080706

Cited by 61 publications

(37 citation statements)

References 23 publications

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“…After careful investigation on the comparison analysis of inversion methods suitable for microwave imaging of the head, Contrast Source Inversion (CSI) or Multiplicative Regularized CSI (MR-CSI) is proposed over other methods because it does not require forward solver recalls during multiple iterations [28,39]. An efficient image reconstruction algorithm based on FEM-CSI will be developed in MATLAB ®…”

Section: Inverse Problem Solutionmentioning

confidence: 99%

An Investigation Into Electromagnetic Based Impedance Tomography Using Realistic Human Head Model

Munawar

Mustansar

Nadeem

et al. 2016

Int J Pharm Pharm Sci

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College of Electrical and Mechanical Engineering, National University of Sciences and Technology, Islamabad, Pakistan Email: awaismunawar.phd06@rcms.nust.edu.pkThe objective of this research is to investigate the feasibility of Electromagnetic based Impedance Tomography (EMIT) for brain stroke detection, localization and classification. Electromagnetic based Impedance Tomography employing microwave imaging technique is an emerging brain stroke diagnostic modality. It relies on the significant contrast between dielectric properties of the normal and abnormal brain tissues. To study the interaction between micro-wave signals and head tissues, the simulations are performed using a geometrically simple 3-D ellipsoid head model with emulated stroke. Finite Element numerical technique is adopted to find the solution of Maxwell's equations to measure the transmitted and backscattered signals in forward problem. Contrast Source Inversion technique is proposed to solve the inverse scattering problem and reconstruct brain images based on calculated dielectric profiles. Detailed analysis is performed to determine the safety limits of transmitted signals to minimize ionizing effects while ensuring maximum penetration. The simulations verify the inhomogeneous and frequency-dispersive behavior of brain tissue's dielectric properties. The solution of the forward problem demonstrates the microwave signals scattering by the multilayer structure of the head model, duly validated by analytical results. The scattering phenomena can be fully capitalized by image reconstruction algorithm to obtain brain images and detect stroke presence. The initial results obtained in this research and prior work indicates that EMIT-based head imaging system has a potential for rapid stroke detection, classification, and continuous brain monitoring and offers a comparatively cost-effective solution.

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Section: Inverse Problem Solutionmentioning

confidence: 99%

An Investigation Into Electromagnetic Based Impedance Tomography Using Realistic Human Head Model

Munawar

Mustansar

Nadeem

et al. 2016

Int J Pharm Pharm Sci

View full text Add to dashboard Cite

show abstract

“…A literature based analysis was performed to compare the accuracy and computational efficiency of different inversion methods suitable for microwave head imaging setup. It was found out that Contrast Source Inversion (CSI) or Multiplicative Regularized CSI (MR-CSI) is preferred over other methods due to its independence on forward solution recalls during multiple iterations [11,45]. Therefore, CSI is proposed to solve the inverse scattering problem of calculating brain tissues' dielectric profiles and reconstructing brain images for stroke detection.…”

Section: Inverse Problem Solutionmentioning

confidence: 99%

Analysis of Microwave Scattering From a Realistic Human Head Model for Brain Stroke Detection Using Electromagnetic Impedance Tomography

Qureshi¹,

Mustansar²,

Maqsood³

2016

PIER M

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Brain stroke incidences have arisen at an alarming rate over the past few decades. These strokes are not only life threatening, but also bring with them a very poor prognosis. There is a need to investigate the onset of stroke symptoms in a matter of few hours by the doctor. To address this, Electromagnetic Impedance Tomography (EMIT) employing microwave imaging technique is an emerging, cost-effective and portable brain stroke diagnostic modality. It has the potential for rapid stroke detection, classification and continuous brain monitoring. EMIT can supplement current brain imaging and diagnostic tools (CT, MRI or PET) due to its safe, non-ionizing and non-invasive features. It relies on the significant contrast between dielectric properties of the normal and abnormal brain tissues. In this paper, a comparison of microwave signals scattering from an anatomically realistic human head model in the presence and absence of brain stroke is presented. The head model also incorporates the heterogenic and frequency-dispersive behavior of brain tissues for the simulation setup. To study the interaction between microwave signals and the multilayer structure of head, a forward model has been formulated and evaluated using Finite Element Method (FEM). Specific Absorption Rate (SAR) analysis is also performed to comply with safety limits of the transmitted signals for minimum ionizing effects to brain tissues, while ensuring maximum signal penetration into the head.

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“…Our desire to model both dielectric and magnetic materials and sources is motivated by biomedical microwave imaging (MWI) applications. PDE formulations of Maxwell's equations readily support inhomogeneous background materials and boundary conditions, and have been recently exploited in MWI algorithms by using an FEM forward solver [17,18]. Recent research suggests the use of magnetic contrast agents for cancer-detecting MWI [19] and so we consider forward solvers that support both magnetic and dielectric materials.…”

Section: Introductionmentioning

confidence: 99%

The Time-Harmonic Discontinuous Galerkin Method as a Robust Forward Solver for Microwave Imaging Applications

Jeffrey¹,

Geddert²,

Brown³

et al. 2015

PIER

Self Cite

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Abstract-Novel microwave imaging systems require flexible forward solvers capable of incorporating arbitrary boundary conditions and inhomogeneous background constitutive parameters. In this work we focus on the implementation of a time-harmonic Discontinuous Galerkin Method (DGM) forward solver with a number of features that aim to benefit tomographic microwave imaging algorithms: locally varying high-order polynomial field expansions, locally varying high-order representations of the complex constitutive parameters, and exact radiating boundary conditions. The DGM formulated directly from Maxwell's curl equations facilitates including both electric and magnetic contrast functions, the latter being important when considering quantitative imaging with magnetic contrast agents. To improve forward solver performance we formulate the DGM for time-harmonic electric and magnetic vector wave equations driven by both electric and magnetic sources. Sufficient implementation details are provided to permit existing DGM codes based on nodal expansions of Maxwell's curl equations to be converted to the wave equation formulations. Results are shown to validate the DGM forward solver framework for transverse magnetic problems that might typically be found in tomographic imaging systems, illustrating how high-order expansions of the constitutive parameters can be used to improve forward solver performance.

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Full-Vectorial Parallel Finite-Element Contrast Source Inversion Method

Cited by 61 publications

References 23 publications

An Investigation Into Electromagnetic Based Impedance Tomography Using Realistic Human Head Model

An Investigation Into Electromagnetic Based Impedance Tomography Using Realistic Human Head Model

Analysis of Microwave Scattering From a Realistic Human Head Model for Brain Stroke Detection Using Electromagnetic Impedance Tomography

The Time-Harmonic Discontinuous Galerkin Method as a Robust Forward Solver for Microwave Imaging Applications

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