scholarly journals Evaluation of reconstruction parameters of electrical impedance tomography on aorta detection during saline bolus injection

2016 ◽  
Vol 2 (1) ◽  
pp. 511-514 ◽  
Author(s):  
Florian Thürk ◽  
Andreas D. Waldmann ◽  
Karin H. Wodack ◽  
Constantin J. Trepte ◽  
Daniel Reuter ◽  
...  
Keyword(s):  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Bolus Injection ◽  
Noise Figure ◽  
Early Stage ◽  
The Body ◽  
Detection Accuracy ◽  
Impedance Tomography ◽  
Saline Bolus ◽  
Hemodynamic Processes

AbstractAn accurate detection of anatomical structures in electrical impedance tomography (EIT) is still at an early stage. Aorta detection in EIT is of special interest, since it would favor non-invasive assessment of hemodynamic processes in the body. Here, diverse EIT reconstruction parameters of the GREIT algorithm were systematically evaluated to detect the aorta after saline bolus injection in apnea. True aorta position and size were taken from computed tomography (CT). A comparison with CT showed that the smallest error for aorta displacement was attained for noise figure nf = 0.7, weighting radius rw = 0.15, and target size ts = 0.01. The spatial extension of the aorta was most precise for nf = 0.7, rw = 0.25, and ts = 0.07. Detection accuracy (F1-score) was highest with nf = 0.6, rw = 0.15, and ts = 0.04. This work provides algorithm-related evidence for potentially accurate aorta detection in EIT after injection of a saline bolus.

Electrical Impedance Tomography of Cell Viability in Tissue With Application to Cryosurgery

2004 ◽  
Vol 126 (2) ◽  
pp. 305-309 ◽  
Author(s):  
Rafael Davalos ◽  
Boris Rubinsky
Keyword(s):  
Electrical Properties ◽  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Cell Damage ◽  
Membrane Integrity ◽  
The Body ◽  
Impedance Tomography ◽  
Cell Membrane Integrity ◽  
Minimally Invasive Surgical Procedure ◽  
Minimally Invasive Surgical

Tissue damage that is associated with the loss of cell membrane integrity should alter the bulk electrical properties of the tissue. This study shows that electrical impedance tomography (EIT) should be able to detect and image necrotic tissue inside the body due to the permeabilization of the membrane to ions. Cryosurgery, a minimally invasive surgical procedure that uses freezing to destroy undesirable tissue, was used to investigate the hypothesis. Experimental results with liver tissue demonstrate that cell damage during freezing results in substantial changes in tissue electrical properties. Two-dimensional EIT simulations of liver cryosurgery, which employ the experimental data, demonstrate the feasibility of this application.

An Electrical Impedance Tomography Drive Pattern for Fast and Accurate Gesture Recognition With Less Electrodes

2019 ◽  
Author(s):  
Gang Ma ◽  
Zhiliang Hao ◽  
Xuan Wu ◽  
Xiaojie Wang
Keyword(s):  
Electrical Impedance Tomography ◽  
Gesture Recognition ◽  
Electrical Impedance ◽  
Recognition Accuracy ◽  
Measurement Time ◽  
Detection Accuracy ◽  
Detection Experiment ◽  
Impedance Tomography ◽  
Electrode Method ◽  
Model Explanation

Abstract This paper presents an optimal Electrical Impedance Tomography (EIT) drive pattern for real-time gesture recognition, which can reduce the measurement time and realize a performance trade-off between the accuracy and the time response. This method is achieved by feature selection and model explanation. We designed eleven hand gestures to verify the proposed approach. Compared to the 8-electrode method, the optimal electrode drive pattern achieved a recognition accuracy of 97.5% with seven electrodes and the measurement time was reduced by 60%. To illustrate the universality of this method, we performed a contact detection experiment. By setting seven labels on the conductive panel and using optimal electrode drive pattern, the detection accuracy reached 100% with seven electrodes and the measurement time was reduced by 85%.

scholarly journals The Factorization Method for Electrical Impedance Tomography Data from a New Planar Device

2007 ◽  
Vol 2007 ◽  
pp. 1-7 ◽  
Author(s):  
Mustapha Azzouz ◽  
Martin Hanke ◽  
Chantal Oesterlein ◽  
Karl Schilcher
Keyword(s):  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Imaging Techniques ◽  
Factorization Method ◽  
The Body ◽  
Impedance Tomography ◽  
Type Method ◽  
Reconstruction Methods ◽  
Tomography Data ◽  
Electrical Impedance Tomography Data

We present numerical results for two reconstruction methods for a new planar electrical impedance tomography device. This prototype allows noninvasive medical imaging techniques if only one side of a patient is accessible for electric measurements. The two reconstruction methods have different properties: one is a linearization-type method that allows quantitative reconstructions; the other one, that is, the factorization method, is a qualitative one, and is designed to detect anomalies within the body.

scholarly journals Automated filtering in the nonlinear Fourier domain of systematic artifacts in 2D electrical impedance tomography

2021 ◽  
Vol 0 (0) ◽  
pp. 0
Author(s):  
Melody Alsaker ◽  
Benjamin Bladow ◽  
Scott E. Campbell ◽  
Emma M. Kar
Keyword(s):  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Electrical Current ◽  
The Body ◽  
Fourier Domain ◽  
Reconstruction Method ◽  
Impedance Tomography ◽  
Conductivity Distribution ◽  
Frequency Regime ◽  
Internal Conductivity

<p style='text-indent:20px;'>For patients undergoing mechanical ventilation due to respiratory failure, 2D electrical impedance tomography (EIT) is emerging as a means to provide functional monitoring of pulmonary processes. In EIT, electrical current is applied to the body, and the internal conductivity distribution is reconstructed based on subsequent voltage measurements. However, EIT images are known to often suffer from large systematic artifacts arising from various limitations and exacerbated by the ill-posedness of the inverse problem. The direct D-bar reconstruction method admits a nonlinear Fourier analysis of the EIT problem, providing the ability to process and filter reconstructions in the nonphysical frequency regime. In this work, a technique is introduced for automated Fourier-domain filtering of known systematic artifacts in 2D D-bar reconstructions. The new method is validated using three numerically simulated static thoracic datasets with induced artifacts, plus two experimental dynamic human ventilation datasets containing systematic artifacts. Application of the method is shown to significantly reduce the appearance of artifacts and improve the shape of the lung regions in all datasets.</p>

scholarly journals Kalman Algorithm Based Electrical Impedance Tomography Imaging

2019 ◽  
Vol 4 (4) ◽  
pp. 52-55
Author(s):  
Md Rabiul Islam
Keyword(s):  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Signal To Noise Ratio ◽  
Spatial Location ◽  
Element Model ◽  
Target Object ◽  
Dielectric Constants ◽  
The Body ◽  
Impedance Tomography ◽  
Ac Current

Electrical Impedance Tomography (EIT) is a non-invasive imaging technique that displays changes in conductivity within a body. This method finds application in biomedical and geology. EIT finds use in medical applications, as the different tissues of the body have different conductivity and dielectric constants. In this paper a phantom model is designed considering Finite Element Model (FEM). AC current of amplitude 1 mA and frequency 1 KHz is applied considering adjacent protocol with noise less and noisy cases. From the computed voltage data image is reconstructed using Kalman algorithm. For noisy case noise levels equal to Signal-to-Noise Ratio (SNR) 30 dB, 15 dB and 7 dB were considered. Kalman algorithm is studied for EIT image reconstruction in noise free and noisy case, in terms of shape, size, spatial location of the target object.

scholarly journals Effect of the number of electrodes on the reconstructed lung shape in electrical impedance tomography

2016 ◽  
Vol 2 (1) ◽  
pp. 499-502 ◽  
Author(s):  
Benjamin Schullcke ◽  
Sabine Krueger-Ziolek ◽  
Bo Gong ◽  
Knut Moeller
Keyword(s):  
Image Quality ◽  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Regional Distribution ◽  
Current Injection ◽  
The Body ◽  
Voltage Measurement ◽  
Impedance Tomography ◽  
The Impact ◽  
Stimulation Pattern

AbstractElectrical impedance tomography (EIT) is used to monitor the regional distribution of ventilation in a transversal plane of the thorax. In this manuscript we evaluate the impact of different quantities of electrodes used for current injection and voltage measurement on the reconstructed shape of the lungs. Results indicate that the shape of reconstructed impedance changes in the body depends on the number of electrodes. In this manuscript, we demonstrate that a higher number of electrodes do not necessarily increase the image quality. For the used stimulation pattern, utilizing neighboring electrodes for current injection and voltage measurement, we conclude that the shape of the lungs is best reconstructed if 16 electrodes are used.

scholarly journals Frequency-Division Multiplexing for Electrical Impedance Tomography in Biomedical Applications

2007 ◽  
Vol 2007 ◽  
pp. 1-9 ◽  
Author(s):  
Yair Granot ◽  
Antoni Ivorra ◽  
Boris Rubinsky
Keyword(s):  
Electrical Impedance Tomography ◽  
Biomedical Applications ◽  
Electrical Impedance ◽  
Experimental System ◽  
The Body ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Voltage Measurement ◽  
Impedance Tomography ◽  
Fourier Decomposition

Electrical impedance tomography (EIT) produces an image of the electrical impedance distribution of tissues in the body, using electrodes that are placed on the periphery of the imaged area. These electrodes inject currents and measure voltages and from these data, the impedance can be computed. Traditional EIT systems usually inject current patterns in a serial manner which means that the impedance is computed from data collected at slightly different times. It is usually also a time-consuming process. In this paper, we propose a method for collecting data concurrently from all of the current patterns in biomedical applications of EIT. This is achieved by injecting current through all of the current injecting electrodes simultaneously, and measuring all of the resulting voltages at once. The signals from various current injecting electrodes are separated by injecting different frequencies through each electrode. This is called frequency-division multiplexing (FDM). At the voltage measurement electrodes, the voltage related to each current injecting electrode is isolated by using Fourier decomposition. In biomedical applications, using different frequencies has important implications due to dispersions as the tissue's electrical properties change with frequency. Another significant issue arises when we are recording data in a dynamic environment where the properties change very fast. This method allows simultaneous measurements of all the current patterns, which may be important in applications where the tissue changes occur in the same time scale as the measurement. We discuss the FDM EIT method from the biomedical point of view and show results obtained with a simple experimental system.

scholarly journals Bone cancer detection using electrical impedance tomography

2021 ◽  
Vol 24 (1) ◽  
pp. 245
Author(s):  
Nabanita Saha ◽  
Mohammad Anisur Rahaman
Keyword(s):  
Computed Tomography ◽  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Imaging Techniques ◽  
Bone Cancer ◽  
Bone Sarcoma ◽  
The Body ◽  
Reconstruction Algorithms ◽  
Impedance Tomography ◽  
Cancerous Cells

Bone cancer is an uncommon sort of malignancy that alludes to irregular development of tissue inside the bone, with high opportunity to spread to different pieces of the body. It is extremely important to distinguish bone cancer at the beginning phase to cure it productively. Presently, in addition to a physical examination, magnetic resonance imaging, blood tests, positron emission tomography (PET), computed tomography (CT) or PET-CT scan, X-ray, Bone scan, Biopsy and computed tomography scan, are used to diagnose or determine the stage (or extent) of bone sarcoma. But these methods are costly and not free of radiation. Moreover, these machines are bulky. Electrical impedance tomography approach was proposed in this research for identifying bone cancer as this detection technique is able to distinguish between cancerous and non-cancerous cells by differentiating between their conductivity and it has the possibility to remove the limitations of conventional medical imaging techniques. Here, equivalent bone models were generated using (electrical impedance and diffused optical reconstruction software (EIDORS) which had been implemented in MATLAB, and three different image reconstruction algorithms-GREIT, Sheffield Backprojection, Gauss-Newton inverse algorithm had been used to detect the cancerous cells.

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