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1
Content available Gaussian pyramid reduction method for the extraction of pathological structures of the aorta
Sobotnicka E., Sobotnicki A., Jeżewski J.
Journal of Medical Informatics & Technologies
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2017
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Vol. 26
37--44
EN
An analysis of the biomedical image in one scale may result in the loss of information contained in the image during an analysis in a different scale. This issue can be solved by an analysis performed simultaneously in all scales, which can be done through the application of the pyramid reduction method. The pyramid makes it possible to obtain images at various levels of detail, including significant information. The paper discusses the method of processing biomedical images of the aorta with the use of the pyramid reduction method, as well as the way in which the results can be used in the segmentation process. The Gaussian pyramid reduction method was used for pyramid representation, whereas the segmentation process was performed with the split and merge method.
2
Content available remote Problematyka zabezpieczenia aparatury elektromedycznej przed skutkami defibrylacji
Mocha J., Wójcik D., Sobotnicki A.
Przegląd Elektrotechniczny
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2014
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R. 90, nr 7
210--213
PL
W artykule zaprezentowano problematykę zabezpieczenia wejść urządzeń elektromedycznych przed skutkami działania impulsu defibrylującego przy zastosowaniu iskierników gazowych. Badania przeprowadzono w układzie pomiarowym zgodnym z normą PN-EN 60601-1:2011. Przedstawiono zarejestrowane napięcia i prądy na poszczególnych elementach dla różnych konfiguracji układu zabezpieczającego oraz oszacowano rozpraszaną przez nie energię. Wartości te determinują krytyczne parametry zastosowanych elementów.
EN
The article presents the issues of protection of input circuits of electromedical devices from external defibrillation shock by using of surge arresters. The study was conducted in the measurement system according to PN-EN 60601-1:2011. Registered voltages and currents on the elements for various configurations of the protection system and estimation of dissipated energy are presented. These values determine the critical parameters of the protection elements.
3
Content available Symulator parametrów rezystancyjnych tkanek do badań bioimpedancyjnych
Piekar E., Sobotnicki A.
Pomiary Automatyka Kontrola
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2014
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R. 60, nr 12
1181--1184
PL
Metodę bioimpedancyjną stosuje się w fizjologii i medycynie klinicznej. Opiera się ona na pomiarze i analizie impedancji elektrycznej żywych tkanek. W pracy przedstawiono sposób implementacji metody bioimpedancyjnej w ocenie zmian objętościowych w układzie krążenia oraz modele stosowane do opisu parametrów elektrycznych naturalnych tkanek. Przedstawiono również zadajnik Reotester symulujący parametry rezystancyjne tkanek opracowany na potrzeby badań aparatury do pomiarów bioimpedancyjnych.
EN
Bioimpedance method is used in clinical medicine and physiology. It is based on the measurement and analysis of electrical impedance of living tissues. This method provides, inter alia, a lot of information about the processes occurring in the circulation and breathing, and its big advantage is noninvasiveness. The paper presents a way of implementing the bioimpedance method in assessment of volume changes in the circulatory system, and the models used to describe the electrical parameters of natural tissues. It also presents the Reotester simulator used to simulate the impedance parameters of the tissues. The simulator allows to generate a constant resistive component of the impedance, modulated by sinusoidal or trapezoidal signal of variable resistance component. The established values of the simulation parameters correspond to the actual ranges of impedance module in the cardio - plethysmographic measurements. The electrical circuit of the simulator consists of a constant resistance in parallel connection with a dedicated photo-resistive element for generating variable component of the resistance. This paper describes the way of implementation of the simulated resistance, the construction of photo-resistive element, and the results of testing and calibration of the simulator. Described simulator is useful tool both, when testing a newly developed device for bioimpedance measurements, as well as for servicing the equipment in the clinical conditions.
4
Content available Determination of stroke volume of the ventricular assist device using bioimpedance method
Sobotnicki A., Gacek A., Pałko T., Mocha J., Badura G., Czerw M.
Journal of Medical Informatics & Technologies
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2013
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Vol. 22
235--241
EN
The stroke volume of pulsatile ventricular assist device (VAD) is one of the key clinical indicators to evaluate the adequacy of the process of mechanical heart assistance and ensuring the patient’s safety. In order to evaluate the volume changes in VAD blood chamber, a bioimpedance method was applied, based on volumetric electric conductivity of the blood. Periodic changes in VAD volume during its operation result in a pulsatile impedance waveform; its amplitude in the subperiods of filling and ejection correlates with blood volume in the chamber. The paper presents the method of analysis of the bioimpedance signal recorded in VAD blood chamber with a reference to the classical method of analysing the cardioimpedance signal from the patient’s thorax. The paper also presents the results of determining stroke volume of blood chamber based on an empirical formula that has been developed.
5
Content available Application of region growing method to brain tumor segmentation - preliminary results
Piekar E., Szwarc P., Sobotnicki A., Momot M.
Journal of Medical Informatics & Technologies
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2013
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Vol. 22
153--160
EN
In this article image have been subject to segmentation using Matlab software, i.e. T1 in normal conditions, perfusion images and images after administering a contrast agent. The tumor in images made in normal conditions was difficult to identify. The images obtained after administering the contrast agent confirmed that the homogeneity criterion has been appropriately selected. In perfusion images the pixels of the background were added to the tumor. When the parameters were changed i.e. pixel counter or neighborhood type the method became more efficient; the tumor boundaries were outlined more precisely. The region growing method enables precise tumor detection; however, the selection of an appropriate homogeneity criterion is a prerequisite for correct segmentation.
6
Content available Measurements of blood saturation inside a ventricular assist device
Mocha J., Czerw M., Sobotnicki A.
Journal of Medical Informatics & Technologies
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2012
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Vol. 19
93--99
EN
Information about the level how well arterial blood is saturated with oxygen, i.e. the overall patient saturation, in particular a patient with a ventricular assist device (VAD) inoculated, is very important for efficient and dependable course of blood circulation support. The paper presents the method for measurement of blood saturation with oxygen that is carried out with use of a commercially available pulse oximetric sensor upon necessary modifications and installed directly on a outflow connector of the VAD. Operability of the presented solution has been verified by experiments on a flow control test bench with use of animal blood. The final validation of the measuring circuit was carried out during experiments with an animal. The completed experiments demonstrated that both the blood saturation with oxygen as well as artificial pulse rate can be measured with accuracy. Unfortunately, similar measurements for venous blood proved infeasible.
7
Content available Evaluation of volumetric parameters of the ventricular assist device using bioimpedance method
Sobotnicki A., Pałko T., Mocha J., Czerw M.
Journal of Medical Informatics & Technologies
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2012
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Vol. 19
117--123
EN
Volumetric parameters of operation of the pulsatile ventricular assist device (VAD) are the key clinical indicators for the evaluation of adequacy of the process of mechanical heart assistance and ensuring the patient's safety. The bioimpedance method has been proposed to evaluate blood volume changes of the VAD. The method is based on volume electric conductivity of the blood. A change in VAD volume involves changes in impedance. Periodic changes in VAD volume during its operation result in a pulsatile impedance wave; its amplitude in the subperiod of filling and ejection correlates with the volume of blood in the VAD. The paper presents the way of acquisition of the bioimpedance signal. It also presents the results of experimental studies, that were carried out with the use of the flow test stand, and an approach to analysing the bioimpedance signal to evaluate the stroke volume.
8
Content available Measurements of blood pressure inside a ventricular assist device
Mocha J., Sobotnicki A., Czerw M.
Journal of Medical Informatics & Technologies
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2011
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Vol. 17
287--293
EN
Information about blood pressure at the inflow and outflow connectors as well as inside a Ventricular Assist Device (VAD) supplemented with information about pressures inside the pneumatic part enables to adjust operational parameters of the VAD in the optimum manner. Practical implementation of a method that makes it possible to measure blood pressure at plurality of points is a really sophisticated task in terms of technical and technological issues. On one hand it is mandatory to assure appropriate metrological properties of the entire measurement path, on the other hand the measuring transducers must be reliably separated from blood. Internal surfaces of these VAD parts that come in direct contact with blood must be smooth and uniform; it is extremely essential due to a risk of blood coagulation on any unevenness of surfaces. The paper presets the solution for measurements of blood pressure inside the VAD, where the suggested solution meets the assumed metrological criteria as well as very stringent safety requirements.
9
Content available QRS complexes detector for synchronization of ventricular assist device
Mocha J., Sobotnicki A., Czerw M., Gibiński P.
Journal of Medical Informatics & Technologies
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2010
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Vol. 16
35--41
EN
Synchronization of operation of an artificial chamber supporting the sick heart of a patient has a crucial meaning for the effectiveness of support. To make the synchronized operation possible, the information on patient's heart activity should be fed to a controller of the supporting chamber. To this end, the QRS complex detector operating on ECG signal is necessary. The signal must be acquired from a patient's heart. Appropriate signal quality at long-term support may be assured only in a case the signal is acquired with epicardial electrodes. In the paper, the concept of hardware construction of a QRS complex detector has been presented, based on a field programmable analog array FPAA. The results of verification of the developed detector include the correct operation while using the epicardial signals recorded from patients which undergone the cardiosurgical operations.
10
Selected metrological and usability aspects of blood pressure measurement by an oscillometric method
Badura G., Gibiński P., Sobotnicki A.
Journal of Medical Informatics & Technologies
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2001
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Vol. 2, Part. 2
MT9--MT15
EN
The article presents conditions of measurement time optimization during cuff inflation, in oscillometric method of blood pressure measurement, assuring most efficient reading at each measurement attempt. The optimization focuses on setting of final pressure, which value is unknown when the measurement begins. Also the time of cuff deflation is optimized by choosing specific deflation method and forming of oscillometric curve in presence of noise in the signal. Apart from that the article presents the process of finding the criterion used for systolic and diastolic pressure estimation. The criterion refers to maximum oscillation amplitude. In the end there are described statistical requirements for accuracy of pressure measurement and a form in which validation results are presented.
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