MEASUREMENT SCIENCE REVIEW Volume 7, Section 2 Main Page | |
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SECTION 2 Download and print the front cover ->>
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Measurement in Biomedicine | |
No. 1 |
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1-4 |
Fereniec M., Kania M., Maniewski R.: Optimal Leads Selection for Repolarization Phase Analysis
Abstract:
The study aimed to identify 12 and 16 optimal recording sites in body
surface potential mapping (BSPM) to assess repolarization phase
differences between healthy volunteers and myocardial infarction groups.
The Discriminant Index and Sequential Selection Algorithm were used to
study averaged ST-T waveform in 61 surface leads. Two methods of selection
of optimal recording sites gave two different lead sets. For diagnosis
purpose leads selected by Discriminant Index value were better, for
approximation of information content the Sequential Selection Algorithm
allowed for selection better recording sites.
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5-11 |
Jamali Dinan F., Mosayebi P., Abrishami Moghaddam H., Giti M.:
Abstract:
This paper presents the application of a new active contour algorithm for
object detection in 3D space. The introduced model is based on techniques
of curve evolution for segmentation and level sets. We minimize an energy
which can be considered as a particular case of the minimal partition
problem. In the level set formulation, the problem becomes a
“mean-curvature flow”-like evolving the active contour, which will stop on
the desired boundary. However, the stopping term does not depend on the
gradient of the image, as in the classical active contour models, but is
instead related to a particular segmentation of the image. The method can
be put into a 3D level-set framework using a Lipschitz function φ for
automatic topology changes. The novel developed 3D algorithm was used for
3D segmentation of endocardial wall in the left ventricle. The
experimental results demonstrated the
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No. 2 |
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12-15 |
Faktorová D.: Complex Permittivity of Biological Materials Measurement at Microwave Frequencies
Abstract:
The paper deals with
complex permittivity measurement of biological materials. The
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16-19 |
Titomir L.I., Trunov V.G., Aidu E.A.I., Sakhnova T.A., Blinova E.V.:
Abstract:
There are presented
results of experimental-laboratory testing a new method to
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No. 3 |
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20-24 |
Majer L., Stopjaková V., Vavrinský E.:
Abstract:
This paper presents a new non-invasive biomedical monitoring of selected
psychosomatic processes. The proposed method measures human skin
conductivity using the interdigitated array (IDA) microelectrodes, which
allow continual monitoring and analysis of complicated physiological,
pathophysiological, and therapeutic processes. The main goal is monitoring
of psycho-galvanic reflex of the human skin that might be very useful for
stress
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25-29 |
Přibil J., Frollo I : Simple Method of Distributed Tuning of RF Sensor for NMR Imaging System Abstract: The paper describes automatic remote tuning system of the NMR tomograph receiving/sending RF sensor based on a coil and two rotating capacitors driven by special DC motors. The tuning unit is permanently located in the NMR scan area, with the stationary magnetic filed B0 needed for DC motors functionality. The tuning control unit equipped by the microcontroller is located in the tomograph operating room, where cooperates with the RF impedance analyser. The conversion, tuning, and regulation characteristics introduced in this paper document obtained results of the first experimental piece of tuning system. Keywords: RF sensor, tuning and matching, NMR imager, automated regulation
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No. 4 |
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30-33 |
Kania M., Fereniec M., Maniewski R.: Wavelet Denoising for Multi-lead High Resolution ECG Signals
Abstract:
The aim of this study
was to investigate the application of wavelet denoising in noise reduction
of multichannel high resolution ECG signals. In particular, the influence
of the selection of wavelet function and the choice of decomposition level
on efficiency of denoising process were considered and whole procedures of
noise reduction were implemented in MatLab environment. The Fast Wavelet
Transform was use. The advantage of
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34-38 |
Šušmáková K., Krakovská A.: Classification of waking, sleep onset and deep sleep by single measures Abstract: The study analyses electrophysiological signals (EEG, EOG, ECG and EMG) to select measures and scoring methods suitable for the detection of sleep stages from waking to deep sleep. 85 measures, selected from relevant spectral characteristics and measures inspired by dynamical systems theory are discussed. Some new characteristics proved to be more sensitive than the conventional scoring measures. Discriminant analysis done with Fisher quadratic classifier determined as the best measures power ratios in delta-alpha, theta-alpha, delta-sigma, delta-beta bands, relative power in delta band, fractal dimension, and coefficient of detrended fluctuation analysis. Keywords: sleep, EEG, rules of Rechtschaffen and Kales, nonlinear, spectral measures
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No. 5 |
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39-42 |
Juráš V., Bittšanský M., Majdišová Z., Trattnig S.: Abstract: The purpose of this study was to evaluate changes of several MR parameters (T1, T2 and ADC) before and after compression in human cartilage samples using unique microimaging compression system. Cartilage samples were prepared from joints of 10 patients, who underwent a total knee joint replacement. Study was performed on a Bruker 3T Medspec whole-body scanner (Bruker, Ettlingen, Germany) using BGA-12 micro-gradients with a special designed compression device built for this gradient system. Employing this equipment there is a possibility to reach accuracy of moving the compressive piston of 1/100 mm. T1 mapping was performed by the inversion recovery spin echo pulse sequence, for T2 mapping a multi-echo multi-slice spin echo sequence was used and ADCs were calculated from data collected from pulsed gradient spin echo (PGSE), all before and after compression. Fitting routines were written in IDL using mpcurvefit routine. Equipment for cartilage compression evaluation seems to be feasible for studying influence of static compression on cartilage tissue. Significant changes of T1, T2 and ADC parameters during compression were found. Biochemical imaging provided by multi-parametric MR improves biomechanical studies of articular cartilage. Keywords: MRI, cartilage, biochemical testing
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43-51 |
Kavitha A., Ramakrishnan S.:
Assessment
of Human Red Blood Cell Aggregation Using Image Processing
Abstract:
Aggregation of
red blood cells which manifests in the form of rouleaux is a major
determinant of flow behavior of blood in both micro and macro circulation.
Any alteration in the normal behavior is found to be a critical factor in
plugging of arterioles and venules forming irreversible clumps. In this
work, the aggregation behavior of red blood cells is analyzed using
Wavelet transforms. The artificially induced red cell aggregate images
obtained from normal adult volunteers are used for the study. An arbitrary
aggregation size index is derived using four different wavelet functions.
The results demonstrate the ability of wavelets to precisely differentiate
variations in degree of aggregation and their intercellular bonding. Also
the aggregation size indices are found to be similar and consistent for a
given aggregate for all wavelet functions. As the association and
dissociation of red cells and the bonding strength during cluster
formation are direct indicators of altered flow behavior of red cells in
micro-vessels and large arteries such analysis seems to be clinically
relevant. The methodology, algorithm and observations based on Wavelet
transforms are discussed in detail.
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No. 6 |
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52-56 |
Hebláková E., Turzová M., Švehlíková J., Tyšler M.: Model-based Assessment of Local Ischemia - Criteria for Localization Credibility Abstract: A method for noninvasive identification of local ischemic lesions from difference integral (DI) maps, based on dipolar representation of the lesion, was previously reported. Aim of this study was to find some criteria enabling to recognize DI maps representing large or multiple ischemic lesions when the dipole-based method is not suitable for ischemia localization and to estimate the level of noise in DI maps. One or two simultaneous ischemic lesions with different sizes and positions in the myocardium were modeled and corresponding DI maps were computed and contaminated by various degree of random noise. Relative difference between square values of dipole and dipole-and-quadrupole residual maps (shares of DI maps not represented by a dipole or dipole and quadrupole) was proposed to identify large or multiple lesions while mean square value of gradients in dipole residual maps was proposed to estimate the noise level. According to our simulations, these criteria can help to estimate the credibility of the noninvasive assessment of local ischemia. Keywords: body surface potential mapping, dipole model of cardiac generator, noninvasive assessment of ischemic lesions
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57-61 |
Rosík V.,
Karas S., Hebláková E., Tyšler M., Filipová S.: Portable Device for High Resolution ECG Mapping
Abstract:
Portable device for multi-channel ECG measurement and body surface
potential (BSP) mapping is introduced and its possible application for
cardiac diagnostic is presented. The device is designed for simultaneous
measurement of up to 144 body surface potentials relatively to a
relocatable reference electrode. Use of active electrodes, driven
grounding electrode and battery operation of the device facilitate optimal
signal quality.
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