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1

An application of a dynamic thermography for studying a relation between thermal and mechanical activities of a skeletal muscle during a static load

Radomski D., Kruszewski K.

Measurement Automation Monitoring

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2017

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Vol. 63, No. 4

139--142

EN

A thermal distribution provides useful information of physiological and pathological processes. However, only a static thermography was applied in the most of medical studies. This paper shows an example of application of a dynamic thermography to study a physiological activity of a skeletal muscle. The goal of the presented work was to study a putative relationship between mechanical and thermal activity of the quadriceps during a static submaximal load. During a strain a dynamic temperature distribution on a thigh surface and a force moment of a knee erector were registered. The performed analysis used a time-dependent mean temperature, a time-dependent standard deviation and an impulse of a force moment. Moreover, we analyzed of autocorrelation functions to compare the dynamics of these parameters. Finally, we showed the nonlinear, statistically significant relationship between spatial-temporal variability of temperature and the force developing by a concentrative contracted quadriceps. A possible biological interpretation of the identified relation is also proposed taking the described mathematical model of muscle heat transfer into account.

2

Identification of a Nonlinear Association between Components of the Electrohysterographical Signal

Radomski D., Małkiewicz A.

International Journal of Electronics and Telecommunications

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2010

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Vol. 56, No. 3

287-290

EN

Electrohysterography is a method for measuring of bioelectrical potentials generated by a contracting uterus. It is used for monitoring of uterine activities mainly during a pregnancy and for prediction of an upcoming pretermlabour. However, there is still unknown the best method of EHG analysis which gives clinically useful information about a uterine activity. To achieve this goal we propose to use information about nonlinear associations between EHG signals registered from an uterine fundus and an uterine cervix. The h² index was applied to identify these relationships. The obtained results reveal that there exists a nonlinear correlation between biopotentials generated from two parts of a pregnant uterus. Moreover, this correlation seems to be higher as a labour is upcoming. It suggests a possibility of using the h² index for prediction of an upcoming labour based on EHG signals.

3

Sensitivity analysis of a sample entropy estimator on its parameters in application to electrohysterographical signals

Radomski D.

Biocybernetics and Biomedical Engineering

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2010

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Vol. 30, no. 2

67-72

EN

An electrohysterographical signal (EHG) represents a bioelectrical activity of a pregnant uterus. The most frequently used method of analysis of EHG is based on entropy indexes, e.g. an approximate entropy or sample entropy index which are dependent on two parameters. Hitherto, these parameters were selected arbitrary apart from their influence on physiological meaning of the EHG signals. The aim of the presented paper was an evaluation of sensitivity of the sample entropy index on its parameters. Moreover, it was computed such value of these parameters which ensured prediction of an upcoming labor on basis on the EHG description by the sample entropy index.

4

Modeling of glucose concentration dynamics for predictive control of insulin administration

Radomski D., Ławryńczuk M., Marusak P. M., Tatjewski P.

Biocybernetics and Biomedical Engineering

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2010

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Vol. 30, no. 1

41-53

EN

The compartmental models, as Hovorka's one, are usually exact but complicated. Thus, they are not suitable for direct usage in nonlinear predictive controllers because of complexity of the resulting controller and numerical problems that may occur. Thus, simplified nonlinear (neural and fuzzy) models are developed in this paper for the future use in the predictive algorithms. Training and structure selection issues are discussed in the context of neural models. The heuristic, easy to obtain, Takagi-Sugeno fuzzy model composed of the control plant step responses is also designed. It is shown that in case of the considered biological process both nonlinear models have significantly better approximation abilities than linear ones.

5

The method of calculation of potential distribution for image reconstruction iterative algorithm in electrical capacitance tomography

Smolik W., Radomski D.

Zeszyty Naukowe. Elektryka / Politechnika Łódzka

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2009

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z. 114

119-125

EN

This paper presents a method of an iterative image reconstruction algorithm with an updating of the sensitivity matrix destined for an electrical capacitance tomography. We propose the new method for solving integral form of Laplace's equation and the fast algorithm for solving a potential equation set basing on the modified version of Thomas algorithm. The results obtained for the noisy numerical phantoms indicated that the proposed algorithm was faster and gave better quality of the reconstructed images in comparing to the classical version of Landweber algorithm.

6

The Matlab's toolbox for iterative image reconstruction in electrical capacitance tomography

Smolik W., Radomski D.

Zeszyty Naukowe. Elektryka / Politechnika Łódzka

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2009

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z. 114

113-118

EN

Investigations impact of image reconstruction algorithms on image qualities is one of important topics in electrical capacitance tomography (ECT). Among many factors affecting comparing results most significant are different models of sensors and phantoms as well as different methods of image errors calculations. Thus, there is a need to elaborate a programming library which helps introducing a standard methodology for evaluation of existed and new image reconstructions procedures applied in ECT. This paper presents such library designed to study of iterative image reconstructions with updating sensitivity matrix.

7

Monitorowanie czynności skurczowej macicy

Radomski D., Grzanka A., Graczyk S.

Elektronika : konstrukcje, technologie, zastosowania

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2008

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Vol. 49, nr 4

139-141

PL

Monitorowanie aktywności skurczowej macicy jest ważnym klinicznym obszarem zastosowań bioinżynierii medycznej. Przedstawiono metodę analizy bioelektrycznej czynności skurczowej macicy. Bazując na nieliniowym modelu opisującym elektrofizjologię skurczu macicy, przedstawiono wykorzystanie wskaźnika entropii z próby sygnału elektromiograficznego macicy do różnicowania aktywności mechanicznej macicy. Uzyskane wyniki sugerują możliwość zastosowania tego wskaźnika do prognozy ryzyka porodu przedwczesnego.

EN

Monitoring of uterine contractions is one of important clinical application of biomedical engineering. This paper describes the new method of an analysis of bioelectrical activity of an uterus. Basing on a non-linear model describing electrophysiology of a uterine muscle contraction, we used the sample entropy index computed for an electrohysterographical signal to differentiate a state of mechanical uterine activities. The obtained results suggest that this index could be used for assessment of a preterm labor risk.

8

Electrical Capacitance Tomograph ET3

Olszewski T., Smolik W., Mirkowski J., Szabatin R., Radomski D., Brzeski P.

Elektronika : konstrukcje, technologie, zastosowania

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2008

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Vol. 49, nr 4

151-157

EN

The standard charge-discharge circuit, used in the measurements of smali electrical capacitances as well as in electrical tomography, has been described and analyzed. Certain improvements have been suggested. The concept of the modular capacitance tomograph has been devised, based on the charge-discharge signal channels, encapsulated on separate PCBs. The practical system uses such signal channels in various configurations suited to the capacitance probes with various electrode configurations. This kind of a system constitutes an optimal platform to develop hardware configurations best suited for various applications.

PL

W artykule zawarto opis i analizę standardowego układu "ładuj-rozładuj", stosowanego do pomiarów małych pojemności elektrycznych w tomografii elektrycznej. Zaproponowano szereg udoskonaleń. Przedstawiono koncepcję modułowego elektrycznego tomografu pojemnościowego, wykorzystującego kanały sygnałów "ładuj-rozładuj", umieszczonych na oddzielnych płytkach obwodów drukowanych. Zbudowany system wykorzystuje kanały sygnałowe w różnych konfiguracjach w zależności od konfiguracji elektrod w sondach pojemnościowych. Zaprezentowany system tworzy optymalną platformę dla rozwoju sprzętu najlepiej dostosowanego do różnorodnych potencjalnych aplikacji.

9

Wykorzystanie akcelerometru do pomiaru drżenia kończyn górnych

Radomski D.

Prace Naukowe Politechniki Warszawskiej. Elektronika

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2007

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z. 161

107-112

EN

Tremor measuring and analysis is a classical diagnostic procedure used in patients with Parkinson`s disease. This paper presents the extension of a tremor analysi enabled through the application of two-axes accelometer with a measuring sensitivity up to 2g.. This measuring sensitivity allowed to measure resting micro-tremors of upper limbs whose sources are finger`s arteriolies. The power spectrum of the analyzed tremor was estimated by continoous wavelet transform using Morlet wavelet as a mother wavelet. The proposed method indicated that the administrated drug caused and identified change of low frecuencies in patients with hypertension. Moreover, it was observed that low frequency oscillations in a rest tremor of upper limbs may coexist with subclinical hypertension.

10

Rola inżynierii biomedycznej w medycynie reprodukcyjnej

Radomski D.

Prace Naukowe Politechniki Warszawskiej. Elektronika

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2006

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z. 157

113-116

EN

Development of modem medicine is strictly associated with an application of biomedical engineering to solve of scientific and clinical problems. The aim of this paper is a review of biomedical engineering application in obstetrics and neonatology. We show the three main applied spaces, i.e. mathematical modeling of reproductive processes, monitoring of mother and fetal health during pregnancies and labors as well as a controI methods of factors ensured comfort of mother and her chiId. The paper presents the selected problems of reproductive medicine which are solved by biomedical engineers and indicates further directions for an application ofbiomedical engineering into reproductive medicine.

11

Systemy ekspertowe w diagnostyce medycznej

Radomski D., Jakubiak A.

Kwartalnik Elektroniki i Telekomunikacji

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2003

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Vol. 49, z. 4

481-502

PL

Dynamiczny rozwój metod laboratoryjnych oraz technik obrazowania radiologicznego przyczynia się do znaczącego wzrostu danych klinicznych, stanowiących merytoryczne przesłanki przy podejmowaniu decyzji diagnoz. Fakt ten utrudnia szybką analizę danych zgromadzonych podczas badania chorego i podjęcie poprawnej decyzji klinicznej, wpływając na wydłużenie procesu diagnostycznego. Aby skrócić czas diagnozy stosowane są systemy ekspertowe wspomagające proces decyzyjny. Mają one głównie zastosowanie w masowych badaniach przesiewowych. Celem artykułu jest omówienie różnych klas systemów ekspertowych, uwzględniających losowy charakter diagnostycznego procesu decyzyjnego. W opisie zawarto również ocenę klinicznej przydatności danej klasy systemu.

EN

Dynamical development of laboratory methods and medical imaging techniques contributes to significant increase of clinical data which circumstances for diagnostic decisions. Therefore, the expert systems are used for computer aided diagnosis, particularly during screening tests. In our consideration, we assume the binary diagnostic decision distinguished between normal and pathological state. In this manner we neglect the differential problem between diseases with similar symptom. We introduce our classification of expert systems depending on their mathematical background. The first class contains systems constructed based on statistical theory of decisions. We show the equivalence between some elements of this theory and the rules of diagnostic decisions making. The first group of these systems is composed of the threshold detectors whose optimal threshold value is calculated based on received -- operating curve (ROC). We present the seldom used method for comparing two or more ROC, by introducing term the curves equivalence. This method is less restrictive than traditional requirement of curves equality but sufficient from diagnostic point of view. We show the example of statistical test, named Schuirmann test which verifies hypothesis about curves equivalence. The other described statistical systems are constructed by logistic regression model a special kind of regression dedicated for binary predictors. We show the method of parameter identification of such model and Wald test for statistical inference about identified parameters. Moreover, we propose and adaptive version of logistic regression where the parameters are updated by EM algorithm. The next class of expert systems is neural systems which are based on neural networks. We show that neural networks can be treated as a generalization of GLM models with least square method of parameters estimation. Therefore, neural networks could be used as nonlinear regression model mapped decision variable set into diagnostic decision. The background of the third class is the fuzzy set theory. We present the main idea of fuzzy sets, showing the standard fuzzy operators and present the concept of fuzzy diagnostic detector. The alternative way which describes uncertainty is the rough set theory. It assumes that a given element belongs to a given rough set if this element will be similar (in sense of special relation) to other elements of the rough set. We present the basic methodology of the rough sets application to diagnostic expert system. The last introduced class is the hybrid systems which combine different previous methodology. We distinguish two structures of hybrid systems, i.e. hierarchical structure and mixture structure. The hybrid expert systems are the most frequent used in clinical practice. The examples of such application are presented too. The last section of this article contains the summarized notes of each class. Our theoretical consideration show that particular classes distinguish the following features: the amount of medical knowledge needed to system building, the size of training sample needed to parameter estimation, the clinical uses. Hybrid systems appear to be the most useful in medical practice.