Practical factors in neonatal lung imaging using electrical impedance tomography

Taktak, A.; Record, Paul; Gadd, R.; Rolfe, P.

doi:10.1007/bf02523042

Cited by 9 publications

(10 citation statements)

References 4 publications

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“…The presence of reactive contact impedances also generates phase shift which can cause misleading measurements. 35 Although contact impedance declines with increasing frequency, it can still reach several hundred ohms at frequencies as high as 100 kHz. On the other hand, tissue impedance is observable between a few kHz to tens of MHz.…”

Section: Contact Impedancementioning

confidence: 99%

“…18,19,22,24,28,29,35,36,40,43 Hydrogel electrode was investigated to be superior to Ag/AgCl electrode to some extent, 36 but the size of it is too huge to be suitable for long-term cerebral monitoring in clinical application. In general, Ag/AgCl electrode is preferable in biosignal recording applications like EIT measurements because it features low and stable offset potentials, low and matched interface impedance, and low polarization, 20 but up to now, there have been many types of Ag/AgCl electrodes by the different techniques, such as powder pressing, filming, hot dip coating and electrolyzing, etc., and the influences on the data measurements of cerebral EIT with different types of Ag/AgCl electrodes have not been explored.…”

Section: Introductionmentioning

confidence: 99%

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Performance Evaluation of Five Types of Ag/AgCl Bio-Electrodes for Cerebral Electrical Impedance Tomography

Dai

et al. 2011

Ann Biomed Eng

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Electrical impedance tomography (EIT) is an emerging medical imaging technique, which has already been investigated in several clinical applications due to its low-cost, non-invasiveness, non-radioactivity, high temporal resolution, and great sensitivity to impedance changes. One potential use of EIT is to perform long-term continuous imaging monitoring of brain for patients who suffer from severe cerebral diseases. However, this application requires a demanding performance of electrodes because of the characteristics of cerebral EIT measurements. Although Ag/AgCl bio-electrodes are widely used for clinical practices or EIT research at the moment, influences of different types of Ag/AgCl electrodes on cerebral EIT measurements have not been investigated. In this study, five common types of Ag/AgCl bio-electrodes were put into comparison by measuring the forearm and the brain of 10 healthy adult volunteers and evaluating those data in frequency or time domain in terms of contact impedance, uniformity, signal-to-noise ratio, and stability. Results show that Ag/AgCl powder electrode has an overall best performance with as low contact impedance as commercial ECG electrodes (p > 0.05), high SNR (60.3 ± 4.5 dB), better uniformity (coefficient of correlation 0.95 ± 0.03), and greater stability (slope 0.68 ± 0.03). After further improvement in design and instrumentation, Ag/AgCl powder electrode is likely to become the optimal choice for cerebral EIT measurements and provide feasible technical support for further research or application in cerebral EIT.

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Section: Contact Impedancementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Performance Evaluation of Five Types of Ag/AgCl Bio-Electrodes for Cerebral Electrical Impedance Tomography

Dai

et al. 2011

Ann Biomed Eng

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“…One obstacle for routine EIT applications in critically ill neonates and infants comes from the ergonomic problems associated with the placement of single electrodes around the neonatal chest with equidistant spacing which requires extensive handling (Hampshire et al 1995, Taktak et al 1995, Frerichs et al 2003, Dunlop et al 2006, Chatziioannidis et al 2011, Miedema et al 2012. Early studies on EIT imaging of the neonatal lung suggested that an electrode belt could be a significant improvement for electrode placement (Hampshire et al 1995).…”

Section: Introductionmentioning

confidence: 99%

Clinical performance of a novel textile interface for neonatal chest electrical impedance tomography

Sophocleous

Frerichs²,

Miedema

et al. 2018

Physiol. Meas.

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“…They have found that at 50 kHz, the real component of the skin impedance under the thorax was less than 80 . In a different study (Taktak et al 1995) nine electrodes types were tested from 10 kHz to 1 MHz on one adult. It was shown that rubber electrodes proved very effective and compared well with different Ag/AgC1 types.…”

Section: Introductionmentioning

confidence: 99%

A comparison study of electrodes for neonate electrical impedance tomography

et al. 2009

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Electrical impedance tomography (EIT) is an imaging technique that has the potential to be used for studying neonate lung function. The properties of the electrodes are very important in multi-frequency EIT (MFEIT) systems, particularly for neonates, as the skin cannot be abraded to reduce contact impedance. In this work, the impedance of various clinical electrodes as a function of frequency is investigated to identify the optimum electrode type for this application. Six different types of self-adhesive electrodes commonly used in general and neonatal cardiology have been investigated. These electrodes are Ag/AgCl electrodes from the Ambu Cardiology Blue sensors range (BR, NF and BRS), Kendall (KittyCat and ARBO) and Philips 13953D electrodes. In addition, a textile electrode without gel from Textronics was tested on two subjects to allow comparison with the hydrogel-based electrodes. Two- and four-electrode measurements were made to determine the electrode-interface and tissue impedances, respectively. The measurements were made on the back of the forearm of six healthy adult volunteers without skin preparation with 2.5 cm electrode spacing. Impedance measurements were carried out using a Solartron SI 1260 impedance/gain-phase analyser with a frequency range from 10 Hz to 1 MHz. For the electrode-interface impedance, the average magnitude decreased with frequency, with an average value of 5 kOmega at 10 kHz and 337 Omega at 1 MHz; for the tissue impedance, the respective values were 987 Omega and 29 Omega. Overall, the Ambu BRS, Kendall ARBO and Textronics textile electrodes gave the lowest electrode contact impedance at 1 MHz. Based on the results of the two-electrode measurements, simple RC models for the Ambu BRS and Kendall-ARBO and Textronics textile electrodes have been derived for MFEIT applications.

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Practical factors in neonatal lung imaging using electrical impedance tomography

Cited by 9 publications

References 4 publications

Performance Evaluation of Five Types of Ag/AgCl Bio-Electrodes for Cerebral Electrical Impedance Tomography

Performance Evaluation of Five Types of Ag/AgCl Bio-Electrodes for Cerebral Electrical Impedance Tomography

Clinical performance of a novel textile interface for neonatal chest electrical impedance tomography

A comparison study of electrodes for neonate electrical impedance tomography

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