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1
Content available Simultaneous recording and analysis of direct and indirect fetal electrocardiography
100%
Matonia A. , Jeżewski J. , Kupka T. , Horoba K. , Bernys M.
Journal of Medical Informatics & Technologies
|
2004
|
tom Vol. 8
MM111--118
EN
Recording and analysis of fetal heart rate variability is still the most common method for detection of early symptoms of fetal hypoxia. However, fetal heart rate obtained via ultrasound describes only mechanical activity of fetus heart. Limitations of this technique have stimulated the development of fetal electrocardiography. It ensures more precise determination of fetal heart rate and, which is more important, enables assessment of the morphology of the fetal QRS complexes. In this paper two techniques of obtaining the fetal electrocardiogram are described and their comparative study is presented.
2
Computerized fetal electrocardiography – elimination of maternal ECG component
100%
Matonia A. , Kotas M. , Jeżewski J. , Horoba K. , Wróbel J. , Kupka T. , Graczyk S.
Journal of Medical Informatics & Technologies
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2000
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tom Vol. 1
BI 101-110
EN
In near future, the noninvasive fetal electrocardiography can substantially alter the perinatal diagnostics. Fetal electrocardiogram is obtained from a signal being recorded on mother’s abdomen. Apart from a useful component, this signal contains artefacts originated from maternal ECG and muscles activity as well as from fetal movements. The primary problem is with effective elimination of maternal electrocardiogram, energy of which many times exceeds a fetal one. Moreover, the spectra of both signals are overlapping thus impeding application of conventional filtration methods in frequency domain. Methods of maternal ECG elimination can be divided into three essential groups: based on adaptive filtration, with the use of weighed summing of signals, and based on orthogonal transformation. In the paper, presented is the description of methods implemented in the system for fetal diagnostics in at-risk pregnancy.
PL
Nieinwazyjna elektrokardiografia płodowa może w niedalekiej przyszłości całkowicie zrewolucjonizować diagnostykę perinatalną. Elektrokardiogram płodu otrzymywany jest z sygnału rejestrowanego na powierzchni brzucha matki. Sygnał ten zawiera, prócz składowej użytecznej, zakłócenia pochodzące od EKG matki, mięśni matki i ruchów płodu. Zasadniczym problemem jest skuteczna eliminacja elektrokardiogramu matki, którego energia wielokrotnie przekracza EKG płodu. Ponadto widma obu sygnałów nachodzą na siebie, utrudniając zastosowanie tradycyjnych metod filtracji w dziedzinie częstotliwości. Metody eliminacji EKG matki można podzielić na trzy zasadnicze grupy: oparte na filtracji adaptacyjnej, wykorzystujące ważone sumowanie sygnałów, oraz bazujące na przekształceniach ortogonalnych. W pracy przedstawiono opis metod, implementowanych w systemie do diagnostyki płodu w ciąży zagrożonej.
3
Content available Improving the quality of the fetal state assessment with epsilon-insensitive learning methods
88%
Czabański R. , Wróbel J. , Jeżewski J. , Łęski J.
Journal of Medical Informatics & Technologies
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2014
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tom Vol. 23
19--26
EN
Recording and analysis of fetal heart rate (FHR) signal is nowadays the primary method for the biophysical assessment of the fetal state. Since the correct interpretation of crucial FHR characteristics is difficult, methods of automated quantitative signal evaluation are still the subject of the research studies. In the following paper we investigated the possibility of improvement of the fetal state evaluation on the basis of the epsilon-insensitive learning (eIL). We examined two eIL procedures integrated with fuzzy clustering algorithms as well as different methods of logical interpretation of the fuzzy conditional statements. The quality of the FHR signal classification was evaluated using the data collected with the computerized fetal surveillance system. The learning performance was measured with the number of correct classification (CC) and overall quality index (QI) defined as a geometric mean of sensitivity and specificity. The obtained results (CC = 88 % and QI = 87 %) show a high efficiency of the fetal state assessment using the epsilon-insensitive learning based methods.
4
Content available Computerized fetal monitoring based on bioelectric signals from maternal abdomen
75%
Matonia A. , Jeżewski J. , Gacek A. , Kupka T. , Horoba K. , Wróbel J.
Journal of Medical Informatics & Technologies
|
2002
|
tom Vol. 4
MT37--47
EN
The paper presents an instrumentation set for effective diagnostics of early symptoms of fetal distress in high-risk pregnancy based on bioelectric signals recording. The representative database of records has been established that enabled the complex analysis of signals recorded on a surface of maternal abdomen. As an outcome, the effective algorithms have been developed for processing both the fetal electrocardiogram and the signal of electrical activity of a uterine muscle. This allowed the development of unique diagnostic system based on external biosignal measurement module connected to the standard personal computer. In this system, like in a classical fetal monitor, the fetal heart rate (FHR) signal together with contraction activity signal of uterine muscle and fetal movement become an essential source of information on fetal condition. In addition, there is a possibility for spectral analysis of FHR signal as well as a morphology assessment of fetal ECG signal.
5
Content available Coincidence of maternal and fetal QRS complexes in view of fetal heart rate determination
75%
Kupka T. , Jeżewski J. , Matonia A. , Wróbel J. , Horoba K.
Journal of Medical Informatics & Technologies
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2002
|
tom Vol. 4
MT49--55
EN
Indirect fetal electrocardiography is a developing diagnostic method in perinatal medicine. Signals of electrical activity being recorded from maternal abdomen surface contain more information than in till now used method of mechanical heart activity measurement based on ultrasound signals. The main problem relies on separation of basic useful component from a signal containing also dominant maternal electrocardiogram and muscles activity artifacts. The algorithms of maternal electrocardiogram suppression via subtraction are commonly used. Although regarding their complexity, these algorithms have limited applicability in systems for long-term monitoring of fetal heart activity. Other solution relies on simple blanking of maternal QRS complexes. However, in case of coincidence of fetal and maternal QRS complexes, this leads to partial loss of information about fetal heart rate variability. For evaluation of how often such coincidence of both complexes takes place, the algorithm has been developed which is described in this paper.
6
Content available Inconsistency in evaluation of clinical patterns in fetal heart rate waveforms
75%
Jeżewski J. , Horoba K. , Wróbel J. , Gacek A.
Journal of Medical Informatics & Technologies
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2002
|
tom Vol. 4
MT27--35
EN
Acceleration and deceleration patterns in fetal heart rate (FHR) are widely used as an assessment of fetal condition. The basis for both visual and automated quantitative analysis is correctly determined fetal heart rate baseline. There are many methods for automated fetal heart rate baseline estimation. Since there are no definitive criteria or "gold standard" to evaluate algorithms for baseline determination, a clinical expert could be considered as a reference. Taking into account that not the shape of baseline itself but the results of quantitative analysis obtained using this baseline are important, we stated that such evaluation should be done only on the basis of comparison of effects - the recognized accelerations and decelerations. However, the first step for such comparison is to check how well expert meets established FIGO definition of accelerations and decelerations patterns in FHR trace. The paper presents a method for evaluation of expert's interpretation of these definitions. Two indices describing the inconsistency among fetal monitoring system and experts have been defined. The results obtained indicate the essential differences in procedure of accelerations/decelerations recognition by the computerized system and human expert.
7
Content available remote Coping with limitations of fetal monitoring instrumentation to improve heart rhythm variability assessment
75%
Kupka T. , Matonia A. , Jezewski M. , Horoba K. , Wrobel J. , Jezewski J.
Biocybernetics and Biomedical Engineering
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2020
|
tom Vol. 40, no. 1
388--403
EN
The most commonly used method of fetal monitoring is based on analysis of the fetal heart activity. Computer-aided fetal monitoring enables extraction of information hidden for visual interpretation – the instantaneous fetal heart rate (FHR) variability. The most natural method of obtaining FHR signal is fetal electrocardiography (FECG), where the FHR has a natural form of unevenly spaced time series of events – heart beats detected in FECG. However, because of problems with FECG recording, the today's instrumentation is based on monitoring of mechanical activity of the fetal heart by means of Doppler ultrasound technique. The ultrasound signal periodicity is determined with autocorrelation methods, so the FHR output signal has a form of evenly spaced instantaneous measurements, some of which are incorrect or duplicate. The aim of the work was to develop a correction algorithm for recognition and removal of these invalid values, to reproduce the FHR signal as time series of events. The new algorithm was compared to other known methods basing on the collected research material and defined performance measures. Thanks to the reference FECG signal registered simultaneously, a detailed analysis of algorithms performance at the level of true heart cycles was possible. Additionally, the influence of signal correction on indices describing the instantaneous FHR variability was evaluated. The obtained results showed that although changing the FHR signal form into time series of events improved the accuracy of indices, but in relation to beat-to-beat variability, that accuracy still does not ensure reliable analysis of instantaneous FHR variability.
8
Content available Improving the periodicity measurement in fetal heart activity signal
75%
Roj D. , Wróbel J. , Horoba K. , Przybyła T. , Kupka T.
Journal of Medical Informatics & Technologies
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2010
|
tom Vol. 16
19--26
EN
In this paper we discussed the influence of preliminary processing of the ultrasound Doppler signal on accuracy of the fetal heart rate estimation as well as on reliability of the FHR instantaneous variability assessment. We attempted to develop an optimal processing channel of US Doppler signal in order to measure the periodicity of fetal heart activity with accuracy as close as possible to that ensured by FECG. The FHR values determined from the US signal were compared to the reference data obtained from direct FECG. In a final evaluation we used the parameters describing the FHR variability as the clinically important signal features being the most sensitive to any periodicity inaccuracy. The results proved that an application of proposed algorithms improves the accuracy of interval measurements and FHR instantaneous variability assessment in relation to the new-generation fetal monitors.
9
Content available Evaluation of predictive capabilities of quantitative cardiotocographic signal features
75%
Czabański R. , Jeżewski M. , Roj D. , Szaszkowski Z. , Kupka T. , Wróbel J.
Journal of Medical Informatics & Technologies
|
2010
|
tom Vol. 16
11--17
EN
Cardiotocography (CTG) is the main method of assessment of the fetal state during pregnancy and labour used in clinical practice. It is based on quantitative analysis of fetal heart rate, fetal movements and uterine contractions signals. The evaluation of the CTG signals can be made using criteria recommended by International Federation of Obstetrics and Gynecology. Nevertheless, the diagnosis verification is possible only after the delivery on the basis of newborn assessment. In the proposed work we evaluated the capacity of quantitative analysis of CTG traces in predicting fetal outcome. The relationship between CTG signal features and attributes of fetal outcome was assessed on the basis of ROC curves analysis. The obtained results indicate the adequate predictive capabilities of the selected CTG features especially for fetal outcome assessed with Apgar score and suggest the necessity of applying the criteria for the CTG traces evaluation that are related to the gestational age. Our study also shows the value of the CTG monitoring as a screening procedure providing appropriate confirmation of fetal wellbeing.
10
Content available remote Modelling of non-invasively recorded maternal and fetal electrocardiographic signals
75%
Matonia A. , Jeżewski J. , Kupka T. , Wróbel J. , Horoba K.
Biocybernetics and Biomedical Engineering
|
2005
|
tom Vol. 25, no. 2
27-39
EN
The fetal electrocardiogram (FECG) recorded from the maternaI abdominal wall, due to its low amplitude, is very sensitive to various interferences. Some of them, like the muscular interferences, are characterized by a wide range of shared frequencies and comparable amplitudes. The most dominant interference - maternaI electrocardiogram - many times exceeds the level of the useful signaI. Contrary to the classical adult's electrocardiography, in fetal electrocardiography, there are no established signal databases (AHA, MIT-BIH) enabling us to perform the testing of the systems and algorithms being under development. This paper presents a method of modelling of artificial signals corresponding to the waveforms recorded on the abdominal wall. The method enables generation of electrocardiographic signals, with strictly determined parameters, and allows us to control the type and level of the noise added. The proposed database with the pattern signals will enable us to test new signal processing the algorithms used in our KOMPOREL System for non-invasive FECG diagnostics.
11
Content available Fuzzy system for evaluation of fetal heart rate signals using FIGO criteria
75%
Czabański R. , Jeżewski M. , Wróbel J. , Jeżewski J. , Horoba K.
Journal of Medical Informatics & Technologies
|
2009
|
tom Vol. 13
189--194
EN
Cardiotocography is a biophysical method of fetal monitoring during pregnancy and labour. It is mainly based on recording and analysis of fetal heart activity. The computerized fetal monitoring systems provide the quantitative description of the recorded signals but the effective methods supporting the conclusion generation are still needed. The evaluation of the signal can be made using criteria recommended by FIGO. Nevertheless, the quantitative description of the traces is inconsistent with qualitative nature of the obstetric knowledge. Therefore, we applied the fuzzy system based on Takagi-Sugeno-Kang model to evaluate and classify signals. FIGO guidelines were used for developing a set of fuzzy conditional rules defining the system performance. The proposed system was evaluated using data collected with computerized fetal surveillance system – MONAKO. The classification results confirm the improvement of the fetal state evaluation quality while using the proposed fuzzy system support.
12
Content available Comparison of instantaneous fetal heart rate extracted from abdominal and direct fetal electrocardiograms
75%
Matonia A. , Kupka T. , Jezewski J. , Momot A. , Jeżewski M. , Bernys M.
Journal of Medical Informatics & Technologies
|
2012
|
tom Vol. 19
101--107
EN
This work is an attempt to assess the reliability of indirect abdominal electrocardiography as an alternative technique of fetal monitoring. As a reference signal we used the simultaneously acquired direct fetal electrocardiogram. Each recording consisted of four signals acquired from maternal abdomen and the reference signal acquired directly from fetal head. The first stage of our study concerned the signal loss episodes. In order to reduce the influence of incorrectly detected R-waves, some certain validation rules were applied. In the second stage, the corresponding intervals determined on basis of both acquisition methods were matched and the accuracy of fetal heart rate measurement was evaluated. Although the accuracy of abdominal electrocardiography turned out to be slightly lower than reported for ultrasound method, it still has some unique features deciding of its prevalence in a certain circumstances.
13
Content available Fetal state evaluation with fuzzy analysis of newborn attributes using CUDA architecture
75%
Czabański R. , Wróbel J. , Jeżewski J.
Journal of Medical Informatics & Technologies
|
2013
|
tom Vol. 22
125--133
EN
Cardiotocography is a biophysical method of fetal state evaluation involving the recording and analysis of the fetal heart rate (FHR). Since a proper interpretation of the signal is relatively difficult, an automatic classification is often based on computational intelligence methods. The quality of classifiers based on supervised learning algorithms depends on a proper selection of learning data. In case of the fetal state evaluation, the learning is usually based on a set of quantitative parameters of FHR signal and the corresponding reference information determined on the basis of the retrospective analysis of newborn attributes. Values of the single attribute have been used so far as a reference. As a result, a part of information on the actual neonatal outcome has always been lost. The following paper presents a method of the fuzzy reasoning leading to an evaluation of neonatal outcome as a function of three newborn attributes. The fuzzy system was used in the process of a qualitative evaluation of the fetal state based on quantitative analysis of FHR signal using a support vector machine (SVM). In order to improve computational effectiveness, the learning algorithm was implemented in Compute Unified Device Architecture (CUDA). The results of these studies confirm the effectiveness of the proposed method and indicate the possibility of practical usage of the fuzzy system in supervised learning algorithms for the qualitative evaluation of the fetal state.
14
New techniques for analysis of fetal electrocardiogram
75%
Matonia A. , Jeżewski J. , Horoba K. , Wróbel J. , Kupka T.
Journal of Medical Informatics & Technologies
|
2001
|
tom Vol. 2, Part. 2
MT33--MT39
EN
Non-invasive fetal electrocardiography may revolutionize perinatal diagnostics in near future. Fetal ECG (FECG) is being extracted from signals recorded on mother’s abdomen. Apart from interesting FECG, the abdominal signal contains interference from mother’s ECG and uterine activity. The major problem is efficient elimination of maternal ECG signal, which energy is several times higher than that of fetal ECG. Furthermore, power spectra of fetal and maternal ECG overlap which makes the use of traditional frequency domain filtering methods difficult. In this paper, an alternative method of spatial filtering is presented, which has been implemented in fetal diagnostic system used in high-risk pregnancy.
15
Instrumentation for fetal monitoring - improvement in Doppler ultrasound technology
63%
Jeżewski J. , Wróbel J. , Horoba K. , Gacek A.
Journal of Medical Informatics & Technologies
|
2001
|
tom Vol. 2, Part. 2
MT17--MT26
EN
The most common noninvasive method of measuring fetal heart rate (FHR) utilizes pulsed Doppler ultrasound monitors. Ultrasound-derived fetal heart intervals are obtained from mechanical movements of the heart valves or heart wall. As distinct from the direct cardiac cycle recording, the analysis of the multi-phase movement process involves difficulties in precise measurement of cardiac interval distances. Linked both to the analog channel and the digital processing from today’s monitors, different factors influencing the quality of the FHR trace are presented. An emphasis is put on autocorrelation techniques for extraction of periodic signal from a noisy background. Two basic forms of autocorrelation function, the autocorrelation with adaptive window selection and crosscorrelation with a changeable template are discussed in detail.
16
Content available Smart selection of signal analysis algorithms for telecare of high-risk pregnancy
63%
Wróbel J. , Matonia A. , Horoba K. , Jeżewski J. , Czabański R. , Pawlak A. , Porwik P.
Journal of Medical Informatics & Technologies
|
2014
|
tom Vol. 23
27--33
EN
Telemedical system for fetal home monitoring with smart selection of signal analysis algorithms is presented in this paper. Fetal monitoring signals are provided by a mobile instrumentation consisting of bioelectrical signal recorder and tablet PC which retrieves and processes the data as well as provides wireless data transmission based on Internet. The fetal surveillance system enables analysis, dynamic presentation and archiving of acquired signals and medical data. Novelty of the proposed approach relies on smart fitting of the algorithms for analysis of the abdominal signals in mobile instrumentation, as well as on controlling of the fetal monitoring session from the surveillance center. These actions are performed automatically through continuous analyzing of the signal quality and the reliability of the quantitative parameters determined for the acquired signals. Using that approach the amount and content of data transmitted through remote channels to the surveillance center can be controlled to ensure the most reliable assessment of the fetal well-being.
17
Antenatal fetal surveillance using bioelectrical signals
63%
Matonia A. , Bernyś M. , Kupka T. , Jeżewski J. , Horoba K.
Elektronika : konstrukcje, technologie, zastosowania
|
2004
|
tom Vol. 45, nr 8-9
110-113
EN
A new approach alternative to cardiotocographic conventional letal monitoring is presented. It relies upon analysis of bioelectrical signals recorded from maternal abdominal wall. Due to strong interferences present in abdominal signal advanced methods of signal processing have been developed to extract letal electrocardiogram and uterine electrical activity signal. The described system allows replacement of more expensive cardiotocographic instrumentation based on ultrasound. Doppler method and ensures the higher diagnostic capacity at the same time.
PL
W pracy przedstawione zostało nowe, alternatywne w stosunku do tradycyjnej kardiotokogralii, podejście do monitorowania stanu płodu w okresie przedporodowym. Zostało ono oparte o rejestrację i analizę biosygnałów rejestrowanych z powierzchni brzucha matki. Występujące w tych sygnałach zakłócenia wymagają stosowania zaawansowanych technik przetwarzania sygnałów w celu wydobycia użytecznej informacji: elektrokardiogramu płodu i sygnału elektrycznej aktywności mięśnia macicy. Opracowany został uniwersalny system do monitorowania płodu pozwalający zastąpić kosztowne aparaty kardiotokograliczne wykorzystujące technikę ultradźwiękową, a zapewniający przy tym znacznie większe możliwości oceny i detekcji stanu zagrożenia płodu.
18
Content available Unsupervised clustering for fetal state assessment based on selected features of the cardiotocographic signals
63%
Przybyła T. , Jeżewski J. , Roj D.
Journal of Medical Informatics & Technologies
|
2009
|
tom Vol. 13
157--162
EN
In modern obstetrics the cardiotocography is a routine method of fetal condition assessment based mainly on analysis of the fetal heart rate signals. The correct interpretation of recorded traces from a bedside monitor is very difficult even for experienced clinicians. Therefore, computerized fetal monitoring systems are used to yield the quantitative description of the signal. However, the effective techniques enabling automated conclusion generation based on cardiotocograms are still being searched. The paper presents an attempt to diagnose the fetal state basing on seventeen features describing the cardiotocographic records. The proposed method applies the unsupervised classification of signals. During our research we tried to classify the fetal state using the fuzzy c-means (FCM) clustering. We also tested how the efficiency of classification could be influenced by application of principal component analysis (PCA) algorithm. The obtained results showed that unsupervised classification cannot be considered as a support to fetal state assessment.
19
Content available remote Recognition of early symptoms of fetal distress with on-line analysis of bioelectrical signals from maternal abdomen
63%
Gacek A. , Matonia A. , Jeżewski J. , Kupka T.
Biocybernetics and Biomedical Engineering
|
2007
|
tom Vol. 27, no. 1-2
207-216
EN
Conventional fetal monitoring for recognition of fetal distress is based on ultrasound Doppler technique. The new approach proposed in this work relies on analysis of bioelectrical signals recorded from the maternal abdominal wall. Fetal electrocardiogram and uterine electrical signal are extracted from abdominal signals using advanced instrumentation and algorithms for signal processing. Evaluation of the fetal heart rate variability with an additional analysis of fetal electrocardiogram morphology is expected to ensure early detection of fetal hypoxia symptoms and, finally, an appropriate obstetrical intervention.
20
Content available remote Automated detection of uterine contractions in tocography signals – Comparison of algorithms
63%
Horoba K. , Wrobel J. , Jezewski J. , Kupka T. , Roj D. , Jezewski M.
Biocybernetics and Biomedical Engineering
|
2016
|
tom Vol. 36, no. 4
610--618
EN
Monitoring of uterine contractile activity enables to control the progress of labor. Automated detection of contractions is an integral part of the signal analysis implemented in computer- aided fetal surveillance system. Comparison of four algorithms for automated detection of uterine contractions in the signal of uterine mechanical activity is presented. Three algorithms are based generally on analysis of the frequency distribution of signal values. The fourth method relies on analyzing the rate of changes of the uterine activity signal. The reference data in form of beginning and end of contraction episodes were provided by human experts. Obtained results show that all algorithms were capable to detect above 91% reference contractions, and less than 7% of recognized patterns were false. Two algorithms can be distinguished as providing a higher performance expressed by the sensitivity of 95% and the positive predictive value of 97%. Such results could be obtained by optimization of contraction validation criteria.
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