scholarly journals Evaluation of Thoracic Equivalent Multiport Circuits Using an Electrical Impedance Tomography Hardware Simulation Interface

Technologies ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 58
Author(s):  
Christos Dimas ◽  
Vassilis Alimisis ◽  
Ioannis Georgakopoulos ◽  
Nikolaos Voudoukis ◽  
Nikolaos Uzunoglu ◽  
...  
Keyword(s):  
Finite Element ◽  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Imaging Modality ◽  
Low Cost ◽  
Element Model ◽  
High Temporal Resolution ◽  
Thoracic Impedance ◽  
Impedance Tomography ◽  
Signal Sampling

Electrical impedance tomography is a low-cost, safe, and high temporal resolution medical imaging modality which finds extensive application in real-time thoracic impedance imaging. Thoracic impedance changes can reveal important information about the physiological condition of patients’ lungs. In this way, electrical impedance tomography can be a valuable tool for monitoring patients. However, this technique is very sensitive to measurement noise or possible minor signal errors, coming from either the hardware, the electrodes, or even particular biological signals. Thus, the design of a good performance electrical impedance tomography hardware setup which properly interacts with the tissue examined is both an essential and a challenging concept. In this paper, we adopt an extensive simulation approach, which combines the system’s analogue and digital hardware, along with equivalent circuits of 3D finite element models that represent thoracic cavities. Each thoracic finite element model is created in MATLAB based on existing CT images, while the tissues’ conductivity and permittivity values for a selected frequency are acquired from a database using Python. The model is transferred to a multiport RLC network, embedded in the system’s hardware which is simulated at LT SPICE. The voltage output data are transferred to MATLAB where the electrical impedance tomography signal sampling and digital processing is also simulated. Finally, image reconstructions are performed in MATLAB, using the EIDORS library tool and considering the signal noise levels and different electrode and signal sampling configurations (ADC bits, sampling frequency, number of taps).

scholarly journals Development of an Anatomically Realistic Forward Solver for Thoracic Electrical Impedance Tomography

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Fei Yang ◽  
Jie Zhang ◽  
Robert Patterson
Keyword(s):  
Electrical Impedance Tomography ◽  
Electric Fields ◽  
Surface Impedance ◽  
Electrical Impedance ◽  
Imaging Modality ◽  
Accuracy Assessment ◽  
Low Cost ◽  
Reconstruction Algorithms ◽  
Impedance Tomography ◽  
Impedance Measurements

Electrical impedance tomography (EIT) has the potential to provide a low cost and safe imaging modality for clinically monitoring patients being treated with mechanical ventilation. Variations in reconstruction algorithms at different clinical settings, however, make interpretation of regional ventilation across institutions difficult, presenting the need for a unified algorithm for thoracic EIT reconstruction. Development of such a consensual reconstruction algorithm necessitates a forward model capable of predicting surface impedance measurements as well as electric fields in the interior of the modeled thoracic volume. In this paper, we present an anatomically realistic forward solver for thoracic EIT that was built based on high resolution MR image data of a representative adult. Accuracy assessment of the developed forward solver in predicting surface impedance measurements by comparing the predicted and observed impedance measurements shows that the relative error is within the order of 5%, demonstrating the ability of the presented forward solver in generating high-fidelity surface thoracic impedance data for thoracic EIT algorithm development and evaluation.

scholarly journals Development and evaluation of a low cost 8-electrode Electrical Impedance Tomography system

2021 ◽  
Vol 2008 (1) ◽  
pp. 012002
Author(s):  
C E Castillo ◽  
A E Álvarez
Keyword(s):  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Imaging Modality ◽  
Low Cost ◽  
Region Of Interest ◽  
Electrical Current ◽  
Maximum Error ◽  
Impedance Tomography ◽  
Homogeneous Test ◽  
Electrical Properties Of Tissues

Abstract Electrical impedance tomography (EIT) is a medical imaging modality that considers the electrical properties of tissues to obtain a conductivity distribution of a region of interest using the level of resistance it presents to the passage of a small electrical current. This work describes the design of an 8-electrode EIT prototype that offers the possibility of changing the excitation parameters and freedom of movement of the demodulation synchrony by means of conventional electronics. The image reconstruction obtained can locate disturbances in the study medium using the adjacent electrode method. A comparison of the voltage measurements acquired on a homogeneous test medium in two different collection cycles was implemented to determine the precision of the system. The data obtained indicate a maximum error percentage of 2.6% between measurements, which represents an acceptable first approach towards the design of a device with greater stability and precision.

scholarly journals Design of low-cost and simple reconstruction method for Three Dimensional Electrical Impedance Tomography (3D-EIT) Imaging

2020 ◽  
Vol 10 (2) ◽  
pp. 125
Author(s):  
Endarko Endarko ◽  
Ari Bangkit Sanjaya Umbu
Keyword(s):  
Electrical Properties ◽  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Imaging Modality ◽  
Low Cost ◽  
Constant Current ◽  
Reconstruction Method ◽  
Pipe Material ◽  
Impedance Tomography ◽  
Pvc Pipe

Electrical impedance tomography is a non-invasive imaging modality that uses the electrical conductivity distribution to reconstruct images based on potential measurements from the object's surface. The proposed study was to design and fabricate a low-cost and simple reconstruction method for 3D electrical impedance tomography imaging. In this study, we have been successfully developed 3 Dimensional Electrical Impedance Tomography (3D-EIT) system using 16 copper electrodes (Cu) to detect and reconstruct the presence of objects in the Phantom. 3D-EIT was developed using Phantom as a test object with PVC pipe material, with an inner diameter of 7.2 cm and a height of 5.4 cm. Electrodes were arranged in two rings, with each ring having eight electrodes arranged in a planar line. Furthermore, the Gauss-Newton algorithm and Laplace prior regularization were used to image reconstruction of objects inside the Phantom using voltage measurement produced from sequential pairs of neighboring electrodes. The voltage is obtained from the injection of a constant current of 1 mA at 20 kHz into the system's electrode pairs. The objects used in this research are PVC pipe, solid aluminum, PVC pipes filled with wax glue, and copper trusses. The results obtained show that the reconstruction results can provide information about the position, the electrical properties, and the shape of real objects. Finally, the system can detect the location, height, and electrical properties of objects for all variations of angle and height variations.

scholarly journals Electrical Impedance Tomography Based on Mixed Finite Element Model

2018 ◽  
Author(s):  
Agah D. Garnadi
Keyword(s):  
Finite Element ◽  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Mixed Finite Element ◽  
Element Model ◽  
Element Formulation ◽  
Reconstruction Algorithms ◽  
Electrical Measurements ◽  
Impedance Tomography ◽  
Conductivity Distribution

Electrical Impedance Tomography (EIT) is a non-invasive imaging technology to map the conductivity distribution of material within confined device from electrical measurements made on the device periphery. The reconstruction of the conductivity distribution images is an inverse problem, which is ill-posed, hence is both extremely sensitive to noise and highly computationally intensive. This paper examines an EIT device based on Mixed Finite Element formulation model. The reconstruction algorithms of images based upon a non-linear least squares criteria.

CALIBRATION OF A LOW COST ELECTRICAL IMPEDANCE TOMOGRAPHY SYSTEM WITH A RING OF RESISTORS AND A KCL SOLUTION

2019 ◽  
Author(s):  
Bruno Furtado de Moura ◽  
francisco sepulveda ◽  
Jorge Luis Jorge Acevedo ◽  
Wellington Betencurte da Silva ◽  
Rogerio Ramos ◽  
...  
Keyword(s):  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Low Cost ◽  
Impedance Tomography ◽  
Tomography System
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