Impedance-based tissue discrimination for needle guidance

Kalvøy, Håvard; Frich, Lars Henrik; Grimnes, Sverre; Martinsen, Ørjan G.; Hol, Per Kristian; Stubhaug, Audun

doi:10.1088/0967-3334/30/2/002

Cited by 85 publications

(81 citation statements)

References 37 publications

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“…The modulus of impedance of the sample between 10 kHz and 1 MHz seems unaffected of electrode impedance, and is in accordance with previous publicized measurements in fat [1] except for the inductor-like increase above 200 kHz. If we model the almost flat level as a resistor, then Z k will be a resistance.…”

Section: B In-vitro Measurementssupporting

confidence: 91%

“…as described in Kalvøy [1]), we have had unexplained detections of positive phase angle in some of our measurements. These have been both for in-vitro laboratory setups and in clinical in-vivo experiments.…”

Section: Introductionsupporting

confidence: 55%

“…6) show a significant effect of electrode impedance for frequencies up to 1-10 kHz. This low frequency phase shift is related to the relatively small electrode area of the needle electrode [1,7]. No significant effects caused by the change on the C g value are expected at low frequency.…”

Section: B In-vitro Measurementsmentioning

confidence: 83%

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Effects of stray capacitance to ground in three electrode monopolar needle bioimpedance measurements

Kalvøy

Aliau-Bonet

Pallás-Areny

et al. 2015

2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

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Abstract-Positive phase angle is documented and analyzed in a three electrode monopolar needle measurement. Inductance equivalent behavior of the stray capacitance to ground is described as error source in a non-inductive sample measurement. I. INTRODUCTIONDuring development of new bioimpedance based applications (e.g. as described in Kalvøy [1]), we have had unexplained detections of positive phase angle in some of our measurements. These have been both for in-vitro laboratory setups and in clinical in-vivo experiments. Some of this behavior has been explained for 4-electrode setups by Grimnes and Martinsen [7]), but positive phase angle have also occurred in our monopolar 3-electrode Solartron® 1260/1294 setups. This has typically been at frequencies between 100 kHz and 1 MHz. The magnitude has been higher than expected from the inductive properties of tissue and it seems not to be fully explained by Grimnes and Martinsen, nor have we been able to avoid the positive phase by different optimizations of our 3-electrode setup. However, Aliau-Bonet and Pallas-Areny[4] addressed stray capacitance to ground as a contributor to apparent inductive behavior in 4-electrode impedance measurements. A manipulation of their 4-electrode equations showed that similar phenomenon may also occur in other setups, and in our hospital environment we have a lot of electronic equipment and large conductive surfaces representing possible stray capacitances between a human body surface and ground.From this we postulate that stray capacitance can partly explain the positive phase angle in our 3-electrode Solartron® 1260/1294 measurement setup. In this paper we have tested this hypothesis by evaluating the theory of AliauBonet and Pallas-Areny on an equivalent circuit modified for 3-electrode setups. Laboratory measurements were also performed to confirm the results from the theoretical analysis. The results have been used to propose strategies to avoid or minimize possible errors.H. Kalvøy is with the Clinical and Biomedical engineering department at Rikshospitalet, Oslo University Hospital, Oslo, Norway. (corresponding author; phone: +47 23 07 15; e-mail: havard.kalvoy@ous-hf.no).C. Aliau-Bonet is with Universitat Politècnica de Catalunya, BarcelonaTech (UPC), Castelldefels, Spain, (e-mail: carles.aliau@upc.edu).R. Pallas-Areny is with Universitat Politècnica de Catalunya, BarcelonaTech (UPC) Castelldefels, Spain (e-mail: ramon.pallas@upc.edu).Ø.G. Martinsen is with the Department of Physics at the University of Oslo, Norway and the Clinical and Biomedical engineering department at Rikshospitalet, Oslo University Hospital, Oslo, Norway (e-mail: ogm@fys.uio). II. MATERIALS & METHODS A. Three electrodes bioimpedance measurementA large piece of bacon was used as sample. The type of biomaterial used is not critical for this study, and bacon has earlier been suggested as a convenient in vitro model for animal or human tissue [2]. A three electrode measurement was implemented by a 1294 impedance interface connected to a 1260 frequency respon...

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Section: B In-vitro Measurementssupporting

confidence: 91%

Section: Introductionsupporting

confidence: 55%

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Effects of stray capacitance to ground in three electrode monopolar needle bioimpedance measurements

Kalvøy

Aliau-Bonet

Pallás-Areny

et al. 2015

2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

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“…The description of sensitivity field for this type of electrode is important in the ongoing project [1] describing a new method for anatomical needle positioning in the clinic.…”

Section: Introductionmentioning

confidence: 99%

Finite element model of needle electrode sensitivity

Høyum

Kalvøy

Martinsen

et al. 2010

J. Phys.: Conf. Ser.

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Abstract. We used the Finite Element (FE) Method to estimate the sensitivity of a needle electrode for bioimpedance measurement. This current conducting needle with insulated shaft was inserted in a saline solution and current was measured at the neutral electrode. FE model resistance and reactance were calculated and successfully compared with measurements on a laboratory model. The sensitivity field was described graphically based on these FE simulations.

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“…Signal generator V in V out when using a small electrode [22]. In addition, the electrical bioimpedance spectrum was measured in 10-kHz intervals of frequency with regard to the designated frequency range.…”

Section: Developed Device For Bioimpedance Measurementmentioning

confidence: 99%

Evaluation of Robust Classifier Algorithm for Tissue Classification under Various Noise Levels

Youn

Shin

Choi

et al. 2017

ETRI J

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Ultrasonic surgical devices are routinely used for surgical procedures. The incision and coagulation of tissue generate a temperature of 40 °C-150 °C and depend on the controllable output power level of the surgical device. Recently, research on the classification of grasped tissues to automatically control the power level was published. However, this research did not consider the specific characteristics of the surgical device, tissue denaturalization, and so on. Therefore, this research proposes a robust algorithm that simulates noise to resemble real situations and classifies tissue using conventional classifier algorithms. In this research, the bioimpedance spectrum for six tissues (liver, large intestine, kidney, lung, muscle, and fat) is measured, and five classifier algorithms are used. A signal-to-noise ratio of additive white Gaussian noise diversifies the testing sets, and as a result, each classifier's performance exhibits a difference. The k-nearest neighbors algorithm shows the highest classification rate of 92.09% (p < 0.01) and a standard deviation of 1.92%, which confirms high reproducibility.

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Impedance-based tissue discrimination for needle guidance

Cited by 85 publications

References 37 publications

Effects of stray capacitance to ground in three electrode monopolar needle bioimpedance measurements

Effects of stray capacitance to ground in three electrode monopolar needle bioimpedance measurements

Finite element model of needle electrode sensitivity

Evaluation of Robust Classifier Algorithm for Tissue Classification under Various Noise Levels

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