Problems in equivalent circuit modelling of the electrical properties of biological tissues

McAdams, ET; Jossinet, J.

doi:10.1016/0302-4598(96)05069-6

Cited by 61 publications

(34 citation statements)

References 8 publications

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“…Whereas the extracellular and intracellular resistances obtained by the Cole-Cole extrapolation technique have been reported to correlate well with extracellular and intracellular fluid volume, respectively (RIGAUD et al, 1996;JAFFRIN et al, 1997), the physical meaning of the capacitance is inexact (MCADAMS and JOSSINET, 1996;RIGAUD et al, 1996). The difficulty in discussing the capacitance is that the capacitance value depends not only on cell membrane capacitance Cm, but also on the size and number of cells, the radii of the bones and thickness of the fat (NOSHIRO et al, 1993).…”

Section: Discussionmentioning

confidence: 96%

Derivation of extracellular fluid volume fraction and equivalent dielectric constant of the cell membrane from dielectric properties of the human body. Part 2: A preliminary study for tracking the progression of surgical tissue injury

Tatara

Tsuzaki

2000

Med. Biol. Eng. Comput.

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A study is conducted to determine whether the extracellular fluid (ECF) volume fraction and equivalent dielectric constant of the cell membrane epsilon m, derived from the dielectric properties of the human body can track the progression of surgical tissue injury. Frequency-dependent dielectric constants and electrical conductivities of body segments are obtained at surgical (trunk) and non-surgical sites (arm and leg) from five patients who have undergone oesophageal resections, before and at the end of surgery and on the day after the operation. The ECF volume fraction and the equivalent epsilon m of body segments are estimated by fitting the dielectric data for body segments to the cell suspension model incorporating fat tissue, and their time-course changes are compared between body segments. By the day after the operation, the estimated ECF volume fraction has increased in all body segments compared with that before surgery, by 0.13 in the arm, 0.16 in the trunk and 0.14 in the leg (p < 0.05), indicating postoperative fluid accumulation in the extracellular space. In contrast, the estimated equivalent epsilon m shows a different time course between body segments on the day after the operation, characterised by a higher change ratio of epsilon m of the trunk (1.34 +/- 0.66, p < 0.05), from that of the arm (0.66 +/- 0.34) and leg (0.61 +/- 0.11). The results suggest that the equivalent epsilon m of a body segment at a surgical site can track pathophysiological cell changes following surgical tissue injury.

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Section: Discussionmentioning

confidence: 96%

Derivation of extracellular fluid volume fraction and equivalent dielectric constant of the cell membrane from dielectric properties of the human body. Part 2: A preliminary study for tracking the progression of surgical tissue injury

Tatara

Tsuzaki

2000

Med. Biol. Eng. Comput.

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“…Although this parametric approach is useM for a basic understanding of cellular properties, the formulas and model parameters themselves do not necessarily have any physical meaning, and therefore uncertainty exists regarding whether changes in model parameter values can be related to underlying physiological events in tissues (MCADAMS and JOSSINET, 1996;RIGAUD et al, 1996). This substantial problem increases the need for a detailed physicochemical model for the derivation of cellular properties from the dielectric properties of human tissues.…”

Section: Impedance Measurementsmentioning

confidence: 98%

Derivation of extracellular fluid volume fraction and equivalent dielectric constant of the cell membrane from dielectric properties of the human body. Part 1: Incorporation of fat tissue into cell suspension model in the arm

Tatara

Tsuzaki

2000

Med. Biol. Eng. Comput.

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The non-invasive characterisation of cell pathophysiology is clinically important. A cell suspension model is applied to derive the extracellular fluid (ECF) volume fraction and the equivalent dielectric constant of the cell membrane epsilon m from the dielectric properties of human arms. Frequency-dependent dielectric constants and electrical conductivities of arms are obtained from 35 surgical patients over a frequency range of 5-1000 kHz. The cell suspension model is applied to fit the data using a complex non-linear least-squares method. The arms show typical dielectric dispersions, although the cell suspension model yields a poor fitting in dielectric constants at lower frequencies and electrical conductivities at higher frequencies. In contrast, a new cell suspension model, taking into account the fat tissue component, remarkably improves the overall fitting performance, allowing estimation of the volume fractions of ECF (0.34 +/- 0.05) and fat tissue (0.16 +/- 0.04) and the equivalent epsilon m (23 +/- 9). The resulting estimates of the volume fraction of fat tissue are in good correlation with arm skinfold thickness (fat volume fraction of arm = 2.42 x 10(-3) x arm skinfold thickness (mm) + 0.099, R = 0.756, p < 0.0001). Therefore it is concluded that the newly derived cell suspension model is well suited for the description of the dielectric properties of human tissues and thus the derivation of the ECF volume fraction and equivalent epsilon m.

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“…= RS/(R ? S) is the resistance at very high frequencies, j is the imaginary unit, a describes a Cole-type distribution of relaxation times and for many tissues and interfaces is a value in the interval 0.7 \ a \ 0.9 [14], and s 0 is the characteristic relaxation time.…”

Section: Impedance Simulationmentioning

confidence: 99%

Frequency-domain reconstruction of signals in electrical bioimpedance spectroscopy

Paterno

Stiz

Bertemes-Filho

2009

Med Biol Eng Comput

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The use of an amplitude/phase retrieval algorithm in electrical bioimpedance spectroscopy (EIS) that allows a new technique to reconstruct the impedance spectrum in the frequency-domain is reported. To the authors' knowledge this is the first time the proposed algorithm has been used to calculate the modulus or phase of a bioimpedance in EIS from one of these two experimentally obtained parameters. The algorithmic technique is demonstrated in EIS, when wide-bandwidth amplifiers,phase-detectors, and high speed converters determine spectra over frequencies up to 500 kHz at isolated points in the frequency interval. Simulated data from bioimpedance models (Cole and 2R1C circuit impedance functions) and experimental data from a known electrical impedance are used to show the applicability and limitations of the technique with a phase retrieval and a modulus retrieval algorithm.Results comparing this technique with the Kramers-Kronig technique that retrieves the imaginary part of an impedance from its real part are also discussed.

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Problems in equivalent circuit modelling of the electrical properties of biological tissues

Cited by 61 publications

References 8 publications

Derivation of extracellular fluid volume fraction and equivalent dielectric constant of the cell membrane from dielectric properties of the human body. Part 2: A preliminary study for tracking the progression of surgical tissue injury

Derivation of extracellular fluid volume fraction and equivalent dielectric constant of the cell membrane from dielectric properties of the human body. Part 2: A preliminary study for tracking the progression of surgical tissue injury

Derivation of extracellular fluid volume fraction and equivalent dielectric constant of the cell membrane from dielectric properties of the human body. Part 1: Incorporation of fat tissue into cell suspension model in the arm

Frequency-domain reconstruction of signals in electrical bioimpedance spectroscopy

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