Comparison of human uterine cervical electrical impedance measurements derived using two tetrapolar probes of different sizes

Gandhi, Saurabh; Walker, Dawn; Brown, Brian; Anumba, Dilly

doi:10.1186/1475-925x-5-62

Cited by 16 publications

(12 citation statements)

References 16 publications

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“…Both magnitude and phase at high frequencies were relatively smaller and more tightly grouped. This has also been observed by other researchers and can be explained by greater ease of penetrating cell walls with high frequency signals [19–21]. Lower frequency signals have greater difficulty penetrating cell walls and injected current tends to follow extracellular paths.…”

Section: Pilot Datasupporting

confidence: 76%

Novel device to trend impedance and fluorescence of the cervix for preterm birth detection

Etemadi

Chung

Heller

et al. 2013

2013 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

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Preterm birth is the leading cause of worldwide neonatal mortality. It follows a pathologically accelerated form of the normal processes that govern cervical softening and dilation. Softening and dilation occur due to changes in cervical collagen crosslinking, which can be measured non-invasively by changes in tissue fluorescence and impedance. We present a novel device designed specifically to take fluorescence and impedance measurements throughout pregnancy, with the end goal of fusing and trending these measurements to form an early diagnosis of preterm labor.

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Section: Pilot Datasupporting

confidence: 76%

Novel device to trend impedance and fluorescence of the cervix for preterm birth detection

Etemadi

Chung

Heller

et al. 2013

2013 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

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“…Impedance can be measured by placing electrodes on the cervix. A study of electrical impedance in 50 nonpregnant and 90 pregnant women found impedance to be decreased in the first trimester cervix as compared to the nonpregnant cervix, but, surprisingly, impedance in late pregnancy were larger than in early pregnancy or the nonpregnant state 42 The authors speculated that perhaps this was due to increased cellular and collagen content in late pregnancy. A subsequent study impedance for prediction of successful labor induction in 200 women presenting for induction at term found that the measurements were only weakly correlated.…”

Section: Quantifying Cervical Remodelingmentioning

confidence: 98%

New techniques in evaluation of the cervix

Feltovich

Carlson

2017

Seminars in Perinatology

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The process of parturition is poorly understood, but the cervix clearly plays a key role. Because of this, recent research efforts have been directed at objective quantification of cervical remodeling. Investigation has focused on two basic areas: (1) quantification of tissue deformability and (2) presence, orientation, and/or concentration of microstructural components (e.g. collagen). Methods to quantify tissue deformability include strain elastography and shear wave elasticity imaging (SWEI). Methods to describe tissue microstructure include attenuation and backscatter. A single parameter is unlikely to describe the complexities of cervical remodeling, but combining related parameters should improve accuracy of cervical evaluation. This chapter reviews options for cervical tissue characterization.

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“…It has been showed that the electrode probe used to measure the impedance of tissue plays an important role for getting accurate readings and hence the measurements can be improved by changing the probe geometry (Jones et al, 2003;Gandhi et al, 2006;Bertemes Filho et al, 2003). Researches performed by Gonzalez-Correa et al (Gonzalez-Correa et al, 2005) showed that the resistivity of various tissues increase as the pressure of the measurement probe is increased.…”

Section: Introductionmentioning

confidence: 99%

Assessing Applied Pressure in Impedance Probe by Single-zone Force Sensing Resistors

Bertemes-Filho¹

2017

AJTE

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Electrical impedance spectroscopy (EIS) is widely used for tissue characterization. Most EIS systems use tetrapolar electrode probes for taking the measurements, which are converted into the electrical properties of the material under study. One of the drawbacks is the applied pressure by the probe, resulting in a change in the measured impedance. The objective of this work is to develop a sensing mechanism for measuring the applied pressure by an electrode probe while measuring the impedance spectra of skin tissue. A system for both measuring the impedance spectra and the equivalent applied force by the probe was set. A measuring circuit of the force was developed by using single-zone force sensing resistors. Calibrations were made by using a sheet of hydrogel under different applied pressures in the frequency range 10 Hz to 1 MHz. Firm and soft pressure was applied in the skin of the distal forearm from a male volunteer of 46 years old. Results showed that the higher the applied pressure the higher the modulus of the impedance is, especially at lower frequencies. This might be important for better characterized tissue with different stiffness and elasticity.

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Comparison of human uterine cervical electrical impedance measurements derived using two tetrapolar probes of different sizes

Abstract: Background: We sought to compare uterine cervical electrical impedance spectroscopy measurements employing two probes of different sizes, and to employ a finite element model to predict and compare the fraction of electrical current derived from subepithelial stromal tissue.

Cited by 16 publications

References 16 publications

Novel device to trend impedance and fluorescence of the cervix for preterm birth detection

Novel device to trend impedance and fluorescence of the cervix for preterm birth detection

New techniques in evaluation of the cervix

Assessing Applied Pressure in Impedance Probe by Single-zone Force Sensing Resistors

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