MEASUREMENT SCIENCE REVIEW                 Volume 3,   Section 2                  Main Page


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VOLUME 3,  2003

  Measurement in Biomedicine

   1 - 4

Tura A., Badanai M., Longo D., Quareni L.:  

A Medical Wearable Device with Wireless Bluetooth-based Data Transmission

Abstract: A medical wearable device has been developed within a project co-funded by the European Community (Karma2 – IST 2001-32320), whose aim is to create a network for the management of Home Care activities in brain-injured children. The device can measure the blood oxygen saturation, the heart rate, the respiration rate and the patient’s quantity of movement. Measured data are stored into a Multimedia Card, and then transmitted to a PC at prescribed time intervals through Bluetooth wireless radio-communication technology. From the PC the measured data are finally transmitted through Internet to a Service Center and hence made available to all professionals involved in patients’ care.

   5 - 8

Plajh I., Cifrek M., Tonković S.:

Characteristics and Application of the Fingerprint Recognition Systems

Abstract:   Fingerprint recognition systems functionality relay on the processing power of the underlying system that implements efficient algorithm for the fingerprint image analysis rather then on the image data acquisition principle efficiency. In this work basic method of the capacitive measurement principle used in most of the systems are analysed. Results lead to the conclusion that some system improvements are also possible through the modification of the existing method.

  9 - 12

Mazic I., Sovilj S., Magjarevic R.:

Analysis of Respiratory Sounds in Asthmatic Infants 

Abstract:   The aim of this study was to validate an asthma monitoring system based on wheezing detection in phonopneumograms. Electronic auscultation and recording of breathing was performed in a group of 26 asthmatic infants (1-7 years) in order to detect the presence of wheezing and determine appropriate respiratory spectra parameters for early detection of possible asthmatic seizures. For recording two types of transducers were used: electret microphones and accelerometers, positioned over the trachea or the chest. The power spectra were calculated and analysed for indicators of wheezing off line. Wheezing was detected in 70% of patients during asthmatic seizures and no wheezing could be detected when no pulmonary obstruction was present.

 13 - 15

Smrčka P., Bittner R., Vysoký P., Hána K.:

Fractal and Multifractal Properties of  Heartbeat Interval Series in Extremal States of the Human Organism

Abstract: The fractal and multifractal properties of human heart rate fluctuations in 2 extremal (but not yet pathological) states are investigated in this study: 1)  sleep deprivation and  2) alcohol intoxication. Namely these states are dangerous in traffic - accidents, car crushes are an epiphenomenon of tired, angry, sleep deprived or (in the worst case) drunken car drivers.  Results of our first pilot experiments are quite promising; it’s possible to distinguish between the vigilant and sleep deprived (or alcohol  intoxicated) person on the basis of fractal analysis of the heartbeat interval series signal.

 17 - 20

Teplan M., Krakovs A., Štolc S.:

EEG in the Context of Audiovisual Stimulation 

Abstract: Audiovisual stimulation of the brain and EEG biofeedback has been studied for their possible applications to variety of conditions. One of the most fundamental principles of biofeedback is the necessity of accurate monitoring and feedback of the physiological processes of interest in order to control it. Here we present application of nonlinear measures and their comparison with spectral measures in detection of different brain states. A group of volunteers was involved in audiovisual stimulation training. EEG was recorded during their attempt for general resting. Following measures were tested: linear correlation, averaged mutual information, spectral edge frequency, relative power of alpha, beta, delta and theta band, spectral entropy, correlation dimension, and results of subjective assessment. Results from this study showed their changes in the course of the training. Nonlinear measures employed deserve further attention.

 21 - 24

Hlavačka F.:

Human Postural Responses to Sensory Stimulations: Measurements and Model 

Abstract:  In the paper we examined the influence of vestibular and leg proprioceptive inputs on the human upright posture. Vestibular input was changed by applying current 1 mA between places near to left and right ear. Proprioceptive input was modified by vibrating the calf muscle. Furthermore, the vestibular stimulus was combined with the muscle vibration using five different temporal relationships between the stimuli. Body postural responses were measured by force platform as a center of foot pressure (CoP) to the support surface. With the anode on the right side, vestibular CoP body response was towards the right side. Vibration of right tibialis anterior muscle induced CoP body shift forward and to the right. With combined stimulation, responses with complex trajectory resulted, which depended on the stimulus interval and reflected a superposition of the single vestibular and proprioceptive effects. The results show that the body vertical is under the continuous control of leg proprioceptive and vestibular inputs. We present a simply model according to which these inputs are averaged by a summation process of several sensory inputs through a parallel sensory feedback in the human posture control system.

 25 - 28

Zilys M., Valinevicius A., Viluckis A.: 

Biometrics Statistical Data Evaluation in the Access Systems 

Abstract: When the information technologies are improving, the security systems are increasingly developing, too. The higher requirements of safety and higher degree of integration are emphasized. In addition to the functional, schemotechnical, and systemic integration, the integrated security is developing. It consists of a variety of technical safety measures that are aggregated into the integral complex of information computing and functioning according to a single algorithm [1]. The procedure of control of persons’ access to certain data plays an important part in the structure of the integrated security system. Now many access control systems that function according to various algorithms of identification has been created. In addition, it is being searched for new ways how to deal with this problem. The biometric identification is one of the new methods of controlling the access system. The objective of this work is to evaluate reliability of use of biometric data, namely, a fingerprint, in the access systems, considering the quality of a fingerprint and appropriate conditions of its approbation.

 29 - 32

Aidu E.A.I., Trunov V.G., Titomir L.I., Capderou A., Vaïda P.:

Transformation of Vectorcardiogram Due to Gravitation Alteration

Abstract: A set of vectorcardiograms recorded during the parabolic flights of a laboratory aircraft was analyzed. It was found that alteration of the gravitation resulted in a linear transformation (rotation and dilatation) of the QRS loop, and only in few cases with disturbances of the heart function the changes of the ECG shape were nonlinear and more complicated. Abrupt changes in the depolarization process may be detected by the nonlinearity of the QRS loop transformation. Characteristics of the transformation (eigenvalues, angles of rotation) can be used as indicators of the heart state changes.

 33 - 36

Aidu E.A.I., Trunov V.G., Titomir L.I., Szathmary V., Tyšler M.:

Noninvasive Location of Acute Ischemic Lesion in the Heart Ventricles Using a Few-lead System: Study on a Realistic Mathematical Model 

Abstract: With the use of an interactive computer model of the cardioelectric generator and body as conducting medium, a   new method for locating the acute ischemic lesion in the heart is investigated. The method is based on recording the unipolar signals with the electrodes of the Frank vectorcardiographic lead system and calculating the displacement of the dipole equivalent cardiogenerator in the direction of its moment vector. It is shown that this method provides recognition of the major anatomical position of the injured region in the heart ventricles for various localizations of the lesion.

 37 - 40

Tyšler M., Turzová M., Švehlíková J.:

Modeling of Heart Repolarization Using Realistic Action Potentials

Abstract:  A computer model for simulation of surface ECG that enables to study heart repolarization changes is introduced. It includes heart geometry and structure description, predefined elemental action potential forms and enables computation of ECG potentials on the surface of an inhomogeneous torso. The influence of the action potentials form on the ST-T part and T-wave of ECG signals is demonstrated.

 41 - 44

Zrubec V., Maňka J.:

Sensitivity of the RF magnetic field receivers with superconducting quantum amplifiers for NMR spectroscopy and tomography 

Abstract: The contribution gives results of the theoretical analysis of the noise properties of the RF magnetic field receivers using the Superconducting Quantum Magnetometer (SQM) for NMR systems with the low magnetic field (Low-Field-NMR). The relation for the equivalent spectral sensitivity of the magnetic induction of the receiver, which covers the influence of the intrinsic noise of SQM, antenna system resistance loss components, the influence of measured sample and their noise temperatures, is given.

 45 - 48

Trefny Z., Hana K., Trojan S., Toman V., Herczegh S., Pousek L., Slavicek J.:

New Trends in Balistocardiography

Abstract: Balistocardiography is a method by which body vibrations caused by heart activity are registered. Evolution during the past fifty years to the present is described. Balistocardiography (BCG) represented by instruments of different natural frequencies and damping should bring information about cardiac output. This expectation was not fulfilled due to the unsuitable physical properties of apparatuses. Quantitative balistocardiography (Q-BCG) was based on the exact physical properties of the newly-developed apparatuses, force acting and force registered were exactly measured and expressed in units of force in Newtons. Quantitative seismography (Q-SCG) opens a new field of cardiovascular dynamics examination. Force applied is registered without amplitude, phase or time distortion. Using this absolutely non-invasive method, a new field of monitoring heart rate variability was opened up. Systolic force as well as heart rate variability in relation to changes in external stimuli are registered. Quantitative seismocardiography probably offers a more complex view of both inotropic and chronotropic heart functions. It will be suitable for: examining operators exposed to stress; for assessing the effect of work, fatigue and mental stress; for monitoring persons as part of disease prevention; for determining a person’s ability to carry out their duties both on the ground and in the air. 

 49 - 52

Hlimonenko I., Meigas K., Vahisalu R.:

Waveform Analysis of Peripheral Pulse Wave Detected in the Fingertip with Photoplethysmograph

Abstract: The aim of this study was to study the elastic properties of vascular tree noninvasively in human subjects as a function of aging using the shape of peripheral pulse wave. We used 21 subjects in two age groups, 22-30, 37-72 years. The peripheral pulse has a steep rise and a notch on the falling slope in the younger subjects. With older subjects a more gradual rise and fall and no pronounced dicrotic notch were observed. The analyzing program calculated ratios t2/t1, P2/P1 and V/P1. As a result, the ratios t2/t1 (p<0.002) and V/P1 (p<0.02) were significantly different between the groups. Two of them could provide a simple, noninvasive means for studying changes in the elastic properties of the vascular system, depending on the age and disease.

 53 - 56

Juroszek B.,  Stanisławski J.:

Synthesis of the Structure of the Respiratory System in Forced Expiration

Abstract: In computational simulation (with MATLAB) RLC lung model was synthesised. The authors of this report presented how sensitive is model form of the conditions of modelling: start point and procedures that select the curve-parameters, according to minimum mean-square error criterion. 

 57 - 66

Bajla I., Holländer I., Kollár M.:

Novel algorithms implemented in the gel image analysis system GAS2

Abstract: A novel implementation of the second generation Gel Analysis System (GAS) with several improvements is presented. The main novelties are: a new module for correction of the smoothing image artifacts using the notch filter in Fourier domain, a new module of the image rectification which speeds up the calculations considerably, and a novel band detection operator based on the template approach which solves some crucial cases of band detection.

 67 - 70

Šmíd R., Ďaďo S.:

Wavelet Correlation for Biomedical Shape Evaluation

Abstract: We propose a method for multiscale evaluation of periodicity of geometrical patterns based on wavelet correlation. This method allows to characterize not only the period but also the scale of periodic components. An application for rotational symmetry estimation of shape of  biomedical objects is described.

 71 - 74

Nessler N., Reischer W., Salchner M.:

Electronic Skin Replaces Volunteer Experiments

Abstract:  Neutral electrodes (grounding plates used in electrosurgical operations) were tested with thermo cameras in volunteers experiments. These experiments are difficult to perform and expensive. A new test device swaroTEST with a measuring board “electronic skin” simulates the relevant electrical features of human skin to replace volunteer experiments. This device consists of a three dimensional resistor network representing the electric features of the skin and muscle tissue, and a temperature sensing array (one transistor for each cm²) to measure the resultant temperature increase after a standardized current load (700 mA hf current during 60 s, proposed in the relevant AAMI HF-18 standard). The comparison of test results with thermo camera images of volunteer experiments showed a sufficient coincidence, which proves the applicability of this test device to replace volunteer experiments.

   75 - 78

Frollo I., Banič B., Mravec B., Juráni M., Greksák M., Macho L., Kvetňanský R.:

Instrumentation for Blood Parameters Measurement in Gravitational Physiology Experiments Using Remote Control

Abstract:  For space biology a new electro-mechanical equipment for multiple blood withdrawal from small experimental animals applied to a centrifuge with maximal 6g gravitational overloading has been developed and tested. The equipment consists of a transmitter and receiver equipped by microcomputers. Active rotor stepping motors are driving four pairs of syringes. It is also possible to measure the instantaneous gravitational force using an accelerometric transducer. This telemetrically regulated blood sampling allows studying selective effects of hypergravity during centrifugation. It can be also used for study of microgravity effects in the animal organism during space flights for the understanding of the mechanism of the changes of the activity of neuroendocrine system and metabolic processes. This instrumentation is also applicable for shifting of small measured samples in the case of imaging using CT or NMR scanners.

 79 - 82

Strolka I., Accardo A., Dreossi D., Vittur F., Toffanin R., Frollo I.:

Segmentation of Magnetic Resonance Microimages of Trabecular Bone: Classifiers and Markov Random Field Model

Abstract:   Quantitative assessment of trabecular bone structure based on magnetic resonance microimages requires a segmentation step, which is difficult to perform because of low signal-to-noise ratio and spatial signal inhomogeneities in these images. In this paper, we present the design of voxel classifiers based on statistical mixture models and classifiers using the feed-forward artificial neural networks (ANN). In both cases a Markov random field (MRF) prior model is used to enhance the reliability of the segmentation process.

 83 - 86

Bačiak L, Szomolányi P., Strolka I., Senaj V., Andris P., Frollo I.:

Time Stability of Static Magnetic Field for Resistive Magnet Systems in NMR Tomography

Abstract:  NMR tomography based on the resistive magnets is advantageous, because of inexpensive operation. Disadvantage is relatively complicated stabilization of the current, which supplies resistive magnet [1,2,3]. Current stabilization has to be used to overcome mistakes in main current caused by the drifts in the power supply, temperature changes of magnet coils, magnet construction, control electronics and shunt-resistor. Current stabilizer compensating problems listed above has been made. Such type of stabilizer has to be used for current stabilization and corresponding magnetic field B0 stabilization of NMR scanners with resistive magnets.

 87 - 89

Šimáček I., Martinická F.:

Magnetizing System for Magnetopneumography

Abstract:  For magnetopneumography a new magnetizing system with two coils and three-phase power supply was made. With the power consumption about 1400 W it is able to generate the magnetic field ranging from 14.9 to 19.8 mT in the space of the volume of 3000 cm3.

 91 - 94

Martinická F., Šimáček I.:

Investigation of the Magnetic Properties of Ni Microparticles for the Utilisation in Magnetopneumography

Abstract:    Magnetopneumography is the method of  investigation of the contamination and of the clearing mechanism of the human lungs based on the  measurement of  the remanent magnetic moment of the magnetised contaminating ferromagnetic particles in the lung. The aim of this work was to find the optimal conditions which enables to provide the most precise  quantification of contaminating ferromagnetic particles in the human lungs. The magnetisation and the relaxation process of spherical Ni particles was   investigated with special attention to the influence  of the magnetisation time, the size and the concentration of the particles and to the viscosity of carrying medium. From the gained results the optimal conditions were concluded and into the praxis implemented.

 95 - 98

Štolc S., Krakovská A., Teplan M.:

Audiovisual Stimulation of Human Brain. Linear and Nonlinear Measures.

Abstract:  One of the most fundamental problems in brain signal analysis is an absence of reliable measures of certain brain states. For purpose of study and detection of such states (especially the state of the mental relaxation which is still not exactly defined) we decided to investigate the influence of commercially well-known mind machines (light & sound machines) on subject’s brain. In this paper we discuss changes in common linear and novel nonlinear measures applied on series of EEG signal recorded before and after mind machine sessions. We will namely discuss linear correlation, mutual information content, spectral entropy, spectral edge frequency and relative power of alpha, beta, delta and theta band.

 99 - 102

Szakolczai K., Haraszti K. and Kozmann G.:

Estimation and Reproducibility Issues in ECG Signal Monitoring. A Simulation Study

Abstract:  Two Important issues of ECG telemonitoring are addressed by statistical modeling. The first one is related to the reproducibility due to inaccurate electrode replacements, the second one is due to inadequate signal estimations if only a limited number of leads are recorded instead of the complete 12-lead system and the unmeasured leads are estimated. The required data of the simulation were extracted from a database of body surface potential maps with 192 leads.  The error terms were represented by correlation coefficients, RMS error histograms and Box and Whisker diagrams. The monitoring by I, II, and V2 leads is presented in depth. 

103 - 106

Stare Z., Protulipac T.:

Sensitivity of the Root Canal Impedance to Electrode Displacement – in vivo and in vitro Measurement

Abstract:  Root canal impedance measurement was carried out in vivo on a series of patients and in vitro on a model (tooth dipped into a saline solution). Impedance was measured for several file tip displacements from apical foramen in the frequency range from 100 Hz to 1 MHz. Comparison between in vivo and in vitro results was performed for the measured value of impedance and for the components (Rp, Cp) of two element parallel equivalent circuit. It has been shown that normalized values obtained on apex have very similar frequency dependence, but the sensitivity to electrode displacement differs great in magnitude and its frequency dependence when measured in vitro from the one obtained in vivo. It is possible to use model – based measurements to draw some conclusions or test apex locator devices if the measurement is conducted on apex, when the file is displaced from apex difference towards in vivo measurement becomes significant.

107 - 110

Kozlíková K., Martinka J., Bulas J., Murín J.:

QRS Complex Isointegral Maps and Left Ventricular Dimensions

Abstract:   In this study extrema of QRS complex isointegral maps (IIM) in relation to echocardiographic (ECHO) parameters were studied. We measured following diastolic heart dimensions: thickness of interventricular septum (IVSd,) left ventricular (LV) posterior wall (LVPWd), and LV internal diameter (LVIDd) on the group of 31 hypertensive patients with and without LV hypertrophy (age 52 ± 12 y, 12 women). We calculated relative wall thickness (RWT), LV mass (LVM) and LVM index (LVMI). The 24 - lead system after Barr was used to record and construct mean IIM QRS as well as IIM of QRS divided into thirds of equal length (QRS1/3, QRS2/3, QRS3/3). We used regression analysis to compare maximum, minimum and peak-to-peak values of all IIMs with ECHO parameters. Only 14 of 72 regression analyses were significant (p < 0.05) with correlation coefficients 0.365 < |r| < 0.667. There was no correlation between IIM QRS1/3 and any ECHO parameter, between any electrocardiographic parameter and RWT. IIM QRS maximum correlated negatively with IVSd. Peak-to-peak values in IIM QRS2/3 and IIM QRS correlated positively with LVIDd. Negative correlations were between minima of IIM QRS2/3, IIM QRS3/3 and IIM QRS and LVPWd, LVIDd, LVM and LVMI. Obtained results probably display different heart geometry and different heart - chest geometry.