Influence of current injection pattern and electric potential measurement strategies in electrical impedance tomography

Silva, Olavo Luppi; Lima, Raúl González; Martins, Thiago C.; Moura, Fernando Silva de; Tavares, Renato Seiji; Tsuzuki, Marcos de Sales Guerra

doi:10.1016/j.conengprac.2016.03.003

Cited by 47 publications

(16 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, this custom-built EIT belt had no influence on radiation attenuation and was well suited for synchronized EIT and 4DCT measurements. EIT Measurements were performed with 3 mA injection current at 195 kHz, skip 4 measurement technique [ 24 ] and a 48 Hz sampling frequency.…”

Section: Methodsmentioning

confidence: 99%

Effects of individualized electrical impedance tomography and image reconstruction settings upon the assessment of regional ventilation distribution: Comparison to 4-dimensional computed tomography in a porcine model

et al. 2017

View full text Add to dashboard Cite

Electrical impedance tomography (EIT) is a promising imaging technique for bedside monitoring of lung function. It is easily applicable, cheap and requires no ionizing radiation, but clinical interpretation of EIT-images is still not standardized. One of the reasons for this is the ill-posed nature of EIT, allowing a range of possible images to be produced–rather than a single explicit solution. Thus, to further advance the EIT technology for clinical application, thorough examinations of EIT-image reconstruction settings–i.e., mathematical parameters and addition of a priori (e.g., anatomical) information–is essential. In the present work, regional ventilation distribution profiles derived from different EIT finite-element reconstruction models and settings (for GREIT and Gauss Newton) were compared to regional aeration profiles assessed by the gold-standard of 4-dimensional computed tomography (4DCT) by calculating the root mean squared error (RMSE). Specifically, non-individualized reconstruction models (based on circular and averaged thoracic contours) and individualized reconstruction models (based on true thoracic contours) were compared. Our results suggest that GREIT with noise figure of 0.15 and non-uniform background works best for the assessment of regional ventilation distribution by EIT, as verified versus 4DCT. Furthermore, the RMSE of anteroposterior ventilation profiles decreased from 2.53±0.62% to 1.67±0.49% while correlation increased from 0.77 to 0.89 after embedding anatomical information into the reconstruction models. In conclusion, the present work reveals that anatomically enhanced EIT-image reconstruction is superior to non-individualized reconstruction models, but further investigations in humans, so as to standardize reconstruction settings, is warranted.

show abstract

Section: Methodsmentioning

confidence: 99%

Effects of individualized electrical impedance tomography and image reconstruction settings upon the assessment of regional ventilation distribution: Comparison to 4-dimensional computed tomography in a porcine model

et al. 2017

View full text Add to dashboard Cite

show abstract

“…The adjacent injection and measurement patterns method is the most commonly used in EIT medical applications. Silva and his colleagues [19], in their work, study the influence of injection and measurement patterns on EIT, concluding that it is not possible to generalize which is the best pattern for reconstruction of EIT images. This implies a study of this characteristic, according to the oriented application of EIT.…”

Section: Injection and Measurement Patternsmentioning

confidence: 99%

“…The multi-frequency systems inject a current signal at different frequencies, obtaining the real and imaginary voltage part, increasing the error in the measurements due to the parasitic capabilities of the multifrequency. Therefore, when using different electrode configurations for current injection and voltage measurement, this is known as the tetra-polar configuration, which was developed by Brown and Seagar in the Mark-Sheffield project in 1987 [19], [21]. One of the methods is that of adjacent electrodes rotating through the 8 pairs of electrodes in the form of a ring, getting 208 measurements that will be used to reconstruct conductivity [22].…”

Section: Injection and Measurement Patternsmentioning

confidence: 99%

Electrical Impedance Tomography: Hardware Fundamentals And Medical Applications

Revelo

2020

ing. Solidar

View full text Add to dashboard Cite

Introduction: The following article shows a systematic review of publications on hardware topologies used to capture and process electrical signals used in Electrical Impedance Tomography (EIT) in medical applications, as well topicality of the EIT in the field of biomedicine. This work is the product of the research project “Electrical impedance tomography based on mixed signal devices”, which took place at the University of Cauca during the period 2017-2019. Objective: This review describes the operation, topicality and clinical use of Electrical Impedance Tomography systems. Methodology: A systematic review was carried out in the IEEE-Xplore, ScienceDirect and Scopus databases. After the classification, 106 relevant articles were obtained on scientific studies of EIT systems; applications dedicated to the analysis of medical images. Conclusions: Impedance-based methods have a variety of medical applications as they allow for the reconstruction of a body region, by estimating the conductivity distribution inside the human body; this is without exposing the patient to the damaging effects of radiation and contrast elements. Impedance-based methods are therefore a very useful and versatile tool in the treatment of diseases such as: monitoring blood pressure, detection of atherosclerosis, localization of intracranial hemorrhages, determining bone density, among others. Originality: It describes the necessary components to design an EIT system, as well as the design characteristics depending on the pathology to be visualized. Restrictions: The review focuses on aspects of the performance of an EIT system, depending on the pathology analyzed. Considering the hardware advances, it is possible to increase the acquisition speed (temporal resolution), thus improving the spatial resolution and the quality of the reconstructed image. Introduction: The following article shows a systematic review of publications on hardware topologies used to capture and process electrical signals used in Electrical Impedance Tomography (EIT) in medical applications, as well topicality of the EIT in the field of biomedicine. This work is the product of the research project “Electrical impedance tomography based on mixed signal devices”, which took place at the University of Cauca during the period 2017-2019. Objective: This review describes the operation, topicality and clinical use of Electrical Impedance Tomography systems. Methodology: A systematic review was carried out in the IEEE-Xplore, ScienceDirect and Scopus databases. After the classification, 106 relevant articles were obtained on scientific studies of EIT systems; applications dedicated to the analysis of medical images. Conclusions: Impedance-based methods have a variety of medical applications as they allow for the reconstruction of a body region, by estimating the conductivity distribution inside the human body; this is without exposing the patient to the damaging effects of radiation and contrast elements. Impedance-based methods are therefore a very useful and versatile tool in the treatment of diseases such as: monitoring blood pressure, detection of atherosclerosis, localization of intracranial hemorrhages, determining bone density, among others. Originality: It describes the necessary components to design an EIT system, as well as the design characteristics depending on the pathology to be visualized. Restrictions: The review focuses on aspects of the performance of an EIT system, depending on the pathology analyzed. Considering the hardware advances, it is possible to increase the acquisition speed (temporal resolution), thus improving the spatial resolution and the quality of the reconstructed image.

show abstract

“…ERT based damage detection applies electric current resulting from an external electric potential at electrode pairs on a specimen surface and measures the electric potential difference between electrode pairs [10] (Figure 1a). Analogously, for ERT on a laminate, electric potentials can be measured [11] (Figure 1b) between: (i) the electrode pair on which electric current is injected, (ii) consecutive electrodes or (iii) a couple of electrodes following a given separation or skip [10].…”

Section: Electrical Resistance Tomography In Cfrp Composite Laminatesmentioning

confidence: 99%

“…Analogously, for ERT on a laminate, electric potentials can be measured [11] (Figure 1b) between: (i) the electrode pair on which electric current is injected, (ii) consecutive electrodes or (iii) a couple of electrodes following a given separation or skip [10]. Electrical resistance values between the electrode pair through which excitation is applied can be determined using Ohm’s law.…”

Section: Electrical Resistance Tomography In Cfrp Composite Laminatesmentioning

confidence: 99%

Optimal Electrode Selection for Electrical Resistance Tomography in Carbon Fiber Reinforced Polymer Composites

2017

View full text Add to dashboard Cite

Electrical Resistance Tomography (ERT) offers a non-destructive evaluation (NDE) technique that takes advantage of the inherent electrical properties in carbon fiber reinforced polymer (CFRP) composites for internal damage characterization. This paper investigates a method of optimum selection of sensing configurations for delamination detection in thick cross-ply laminates using ERT. Reduction in the number of sensing locations and measurements is necessary to minimize hardware and computational effort. The present work explores the use of an effective independence (EI) measure originally proposed for sensor location optimization in experimental vibration modal analysis. The EI measure is used for selecting the minimum set of resistance measurements among all possible combinations resulting from selecting sensing electrode pairs. Singular Value Decomposition (SVD) is applied to obtain a spectral representation of the resistance measurements in the laminate for subsequent EI based reduction to take place. The electrical potential field in a CFRP laminate is calculated using finite element analysis (FEA) applied on models for two different laminate layouts considering a set of specified delamination sizes and locations with two different sensing arrangements. The effectiveness of the EI measure in eliminating redundant electrode pairs is demonstrated by performing inverse identification of damage using the full set and the reduced set of resistance measurements. This investigation shows that the EI measure is effective for optimally selecting the electrode pairs needed for resistance measurements in ERT based damage detection.

show abstract

Influence of current injection pattern and electric potential measurement strategies in electrical impedance tomography

Cited by 47 publications

References 24 publications

Effects of individualized electrical impedance tomography and image reconstruction settings upon the assessment of regional ventilation distribution: Comparison to 4-dimensional computed tomography in a porcine model

Effects of individualized electrical impedance tomography and image reconstruction settings upon the assessment of regional ventilation distribution: Comparison to 4-dimensional computed tomography in a porcine model

Electrical Impedance Tomography: Hardware Fundamentals And Medical Applications

Optimal Electrode Selection for Electrical Resistance Tomography in Carbon Fiber Reinforced Polymer Composites

Contact Info

Product

Resources

About