High-Precision Electrical Impedance Tomography Data Acquisition System for Brain Imaging

Shi, Xuetao; Li, Wei-Chen; You, Fengming; Huo, Xuyang; Xu, Canhua; Ji, Zhenyu; Liu, Ruigang; Liu, Benyuan; Li, Yandong; Fu, Feng; Dong, Xiuzhen

doi:10.1109/jsen.2018.2836336

Cited by 90 publications

(71 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Since the measurement accuracy has been reduced, the RE has increased accordingly, reaching the unacceptable for typical EIT design levels of 4-5% (see the 4 highest values in Figure 8). However, in the literature RE is measured at homogeneous saline tanks of σ = 0.05 S/m to 0.1 S/m [5,9,28]; a value much lower than the current value of 0.2 S/m. Therefore, the low salt concentration RE levels are more representative for the hardware's performance.…”

Section: Discussioncontrasting

confidence: 65%

“…The corresponding RE was estimated at 0.81% (pointed with a green triangle in Figure 8). That satisfies the EIT literature hardware standards (RE < 2% for typical performance, RE < 1% for high performance) [5,9,28].…”

Section: Discussionsupporting

confidence: 57%

“…Small modifications have also been performed on the Howland VCCSs in order to prevent oscillations (capacitors parallel to the negative feedback [9]). Some other implementations included the mirrored VCCS [1,26] or other approaches (Bragos) [27,28]. In [28] the current imbalance between source and sink is addressed by measuring the current and adjusting its amplitude.…”

Section: Voltage-to-current Conversionmentioning

confidence: 99%

“…Some other implementations included the mirrored VCCS [1,26] or other approaches (Bragos) [27,28]. In [28] the current imbalance between source and sink is addressed by measuring the current and adjusting its amplitude. Most of those systems are characterized by z out from a hundred to several hundreds of kΩ at [10,100] kHz.…”

Section: Voltage-to-current Conversionmentioning

confidence: 99%

“…where u(i, j) I(m,n) is the voltage difference between electrodes i and j when current is injected from electrodes m and n [9,28].…”

Section: Error Estimationmentioning

confidence: 99%

See 4 more Smart Citations

A Parametric EIT System Spice Simulation with Phantom Equivalent Circuits

2020

View full text Add to dashboard Cite

In this paper a number of LT Spice simulations have been carried out on an Electrical Impedance Tomography (EIT) system, which includes the whole analog and digital circuitry as well as the subject to be examined (phantom model). The aim of this study is to show how the analog and digital parts, the electrodes and the subject’s physical properties may impact the measurements and the quality of the reconstructed image. This could provide a useful tool for designing an EIT system. Special attention has been given to the current source’s output impedance and swing, to the noise produced by the circuits and to the Analog to Digital Converters (ADCs) resolution and sampling rate. Furthermore, some 3D phantom subjects have been modeled and simulated as equivalent circuits, merged with the EIT simulated hardware, in order to observe how changes on their properties interact with the whole circuitry and affect the final result. Observations show that mirrored current sources with z o u t > 350 k Ω and sufficiently high ADC acquisition sampling rate ( f s a m p l e ≥ 16 f i n ) can result to accurate impedance measurements and therefore quality image reconstruction within a frequency span of at least 10 to 100 kHz. Moreover, possible hardware failures (electrode disconnections and imbalanced contact impedances) can be detected with a simple examination of the first extracted image and measurement set, so that by direct modification of the reconstruction process, a corrected result can be obtained.

show abstract

Section: Discussioncontrasting

confidence: 65%

Section: Discussionsupporting

confidence: 57%

Section: Voltage-to-current Conversionmentioning

confidence: 99%

Section: Voltage-to-current Conversionmentioning

confidence: 99%

“…where u(i, j) I(m,n) is the voltage difference between electrodes i and j when current is injected from electrodes m and n [9,28].…”

Section: Error Estimationmentioning

confidence: 99%

See 3 more Smart Citations

A Parametric EIT System Spice Simulation with Phantom Equivalent Circuits

2020

View full text Add to dashboard Cite

show abstract

Design and implementation of high precision servo channel loading card for fatigue testing of aircraft wings

Zhao

Xiao

Shen

2023

Circuit Theory & Apps

View full text Add to dashboard Cite

SummaryA servo channel loading card (SCLC) with high precision data acquisition and output is developed for static and fatigue testing of aircraft wings. A high‐performance processor field programmable gate array (FPGA) is at the core to control the excitation source (ES) output circuit to provide excitation for the force and displacement sensor. To improve the precision of the ES output circuit, a 3DA‐based ES auto‐calibration circuit is designed. Simulation results show that the 3DA improves the precision of the automatic calibration of the ES circuit. The sensor signals are collected through high precision analog channels, and the signals are automatically zero calibrated and numerical control gain processed. Ultimately, a voltage or current signal is generated through the drive circuit to control the electro‐hydraulic servo loading system to complete a high precision force loading test on the aircraft wings. The experimental results show that the board designed has high reliability in both acquisition and output. The ES output achieved a precision of 0.1375 mV/V, the precision of signal acquisition achieves a precision of −0.175 mV/V, and the servo drive output achieves a precision of −0.06 mV/V, meeting the expected design precision of 1 mV/V.

show abstract

Conductivity characteristics of human lung tissues

Wang

Yue

2021

Int J Imaging Syst Tech

View full text Add to dashboard Cite

In the treatment of lung cancer, bedside monitoring plays an important role.X-ray computed tomography, as a mostly used technique, cannot provide medical surveillance for lung cancer patients in real-time. In comparison, electrical impedance tomography (EIT) has the potential to solve the issue by visualizing human respiratory system; however, its spatial resolution is too low to locate the real pulmonary lesions. One feasible method is to incorporate priori information into the process of EIT imaging. This study aims to investigate the conductivity characteristics of human lung tissues as priori information. First, the impedance spectra of human lung tissues in surgical operation were measured in time in a measurement system. Then, two-and three-dimensional lung models were established. Finally, the conductivity distribution models of cancerous and normal lung tissues were established. Overall, the conductivity of left lung was larger than that of right lung; the conductivity of lower lobe was larger in left lung, whereas the conductivity of upper lobe was larger in right lung. When tissues became cancerous, the conductivity increased by 33.5% on average, and by 34.8 and 31.4% in the left and right lung, respectively. The conductivity in left lung changed more obviously; and it changed more obviously in posterior basal segment of lower lobe in left lung, as well as at apex in right lung. These conclusions can lay the foundation for the further research of improving the spatial resolution of EIT for lung cancer monitoring.

show abstract

High-Precision Electrical Impedance Tomography Data Acquisition System for Brain Imaging

Cited by 90 publications

References 32 publications

A Parametric EIT System Spice Simulation with Phantom Equivalent Circuits

A Parametric EIT System Spice Simulation with Phantom Equivalent Circuits

Design and implementation of high precision servo channel loading card for fatigue testing of aircraft wings

Conductivity characteristics of human lung tissues

Contact Info

Product

Resources

About