A MATLAB-Based Boundary Data Simulator for Studying the Resistivity Reconstruction Using Neighbouring Current Pattern

Abstract

Phantoms are essentially required to generate boundary data for studying the inverse solver performance in electrical impedance tomography (EIT). A MATLAB-based boundary data simulator (BDS) is developed to generate accurate boundary data using neighbouring current pattern for assessing the EIT inverse solvers. Domain diameter, inhomogeneity number, inhomogeneity geometry (shape, size, and position), background conductivity, and inhomogeneity conductivity are all set as BDS input variables. Different sets of boundary data are generated by changing the input variables of the BDS, and resistivity images are reconstructed using electrical impedance tomography and diffuse optical tomography reconstruction software (EIDORS). Results show that the BDS generates accurate boundary data for different types of single or multiple objects which are efficient enough to reconstruct the resistivity images for assessing the inverse solver. It is noticed that for the BDS with 2048 elements, the boundary data for all inhomogeneities with a diameter larger than 13.3% of that of the phantom are accurate enough to reconstruct the resistivity images in EIDORS-2D. By comparing the reconstructed image with an original geometry made in BDS, it would be easier to study the inverse solver performance and the origin of the boundary data error can be identified.

Noninvasive Electromagnetic Methods for Brain Monitoring: A Technical Review

“…Among the signal acquisition method the major electromagnetic methods are electroencephalography (EEG), Magnetoencephalography (MEG), Electrocorticography (ECoG), electroneurogram (ENG). On the other hand, the magnetic resonance imaging (MRI) [40,73,101,133,168,205], Functional MR Imaging (fMRI) [37,39,68,132,146,172] and electrical impedance tomography (EIT) [23,24] are the brain imaging modalities.…”

“…For a current injection through a particular current electrode pair, the boundary voltage current data are collected from all voltage electrode pairs excluding the pairs containing one or two current electrodes. Current injection through a particular current electrode pair and the voltage data collection from all the voltage electrode pairs is called a projection [19,23,29,30]. The fashion in which the current injection electrodes and voltage collections electrodes are switched is called the current pattern [19,23,29,30].…”

“…Though X-Ray computed tomography [4,56,75,85] and magnetic resonance imaging (MRI) [75,121,184,207] provides a lot of information about the human brain anatomy and physiology, still, the electromagnetic methods have their own advantages and potentials in brain monitoring. Being the fast, radiation free and noninvasive techniques, the electromagnetic brain monitoring and investigations [8,10,23,24,97,98,153,157,181] are being researched by a number of research groups over the world.…”

“…It will then present the present scenario of the conventional brain monitoring methods with their merits and demerits. The chapter will next present the introduction to the electromagnetic brain monitoring techniques such as Electroencephalography (EEG) [7,10,98,137], Magnetoencephalography (MEG) [10,98,157], Electrocorticography (ECoG) [153], electroneurogram (ENG) [181], electrical impedance tomography (EIT) [23,24], Quantitative susceptibility mapping (QSM) [135,136] and other advanced brain monitoring modalities. The chapter will discuss about their working principles and other technical aspects along with their advantages, disadvantages and challenges.…”

A 3D multi-frequency response electrical mesh phantom for validation of the planar structure EIT system performance

“…In general the mesh phantoms are designed to assess and evaluate the performance of the EIT system by providing reconfigurable conductivity distributions [9]. Using a mesh phantom can reduce the difficulty of calibration and validation of the design as it is relatively simple and quick to use [10,11].…”