Wyniki wyszukiwania - Biblioteka Nauki

1

Analysis of blood pressure wave in the human common carotid artery on the basis of non-invasive ultrasonic examinations

100%

Powałowski T.

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tom Vol. 25, no. 2

191-204

EN

The aim of the study was the examination of the forward and reflected blood pressure waves in the common carotid artery on the basis of non-invasive ultrasonic examinations. The study concerned the effect of stenosis of the internal carotid artery caused by atherosclerosis on the mean reflection coefficient modulus and the time delay between the reflected blood pressure wave and the forward blood pressure wave. The investigations were carried out on a group of healthy persons (30 cases) and on a group of sick persons (17 cases) with stenosis or occlusion of the internal carotid artery.

2

Ultrasonic examination of common carotid artery wall elasticity of persons with different stages of internal carotid artery atherosclerosis

51%

Powałowski T. , Trawiński Z. , Hilgertner R.

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tom Vol. 28, no. 4

325-337

EN

Ultrasonic methods were used in this study to examine the association between the common carotid artery (CCA) wall elasticity and the atherosclerosis stage in the internal carotid artery (ICA). The degree of stenosis determined ultrasongraphically was used as an indicator of the atherosclerosis stage in the ICA. The examined persons were 45 to 80 years old. They had no arterial hypertension, diabetes mellitus and were not smokers. A comparative study was carried out for cases with ICA atherosclerosis (66 arteries) and without ICA atherosclerosis (61 arteries). In both groups there were persons without and with hypercholesterolemia, which according to our studies had no significant influence on CCA wall elasticity. The CCA wall elasticity was determined by the stiffness coefficient alpha and the distensibility coefficient DC based on ultrasonic measurements. The influences of age and arterial blood pressure on the CCA wall elasticity were taken into account in the analysis. The study revealed a significant decrease of the CCA wall elasticity in the case of patients with atherosclerosis compared with persons without atherosclerosis, and showed a significant correlation between the increase of the ICA stenosis degree and the decrease of CCA wall elasticity.

3

Numerical solver of acoustic field in simulation of artery wall thickness examinations

51%

Powałowski T. , Wójcik J. , Trawiński Z.

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tom Vol. 10

163-168

EN

The aim of the study was the elaboration of a mathematical model to describe the process of acoustic wave propagation, generated by an ultrasonic probe in a inhomogenous loosing medium. Numerical calculations make it possible to define waveforms for electric signals that are generated when ultrasonic waves, being reflected and backscattered by an artery model, are then received by the ultrasonic probe. It is the signal that pretty well corresponds with the actual RF signal that is obtained during measurements at the output of the ultrasonic apparatus. The developed solver of acoustic field was used for simulation of the artery wall thickness examination. The theoretical model of the artery for the creating the simulated ultrasonic reflected echoes was used. The internal radius of the artery model was 3 mm for the diastolic pressure and 3.3 mm for the systolic pressure. The intima-media thickness (IMT) of the artery wall was changed from 0.48 mm to 0,44 mm respectively. The solver based on zero-crossing method was used for detecting changes of the IMT.

4

Common carotid wall elasticity and intima-media thickness examinations by means of ultrasound

51%

Powałowski T. , Hilgertner R. , Trawiński Z.

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tom Vol. 25, no. 2

205-212

EN

The aim of this study was to examine the relation between the intima-media thickness and the wall elasticity measured simultaneously in the same cross-section of the common carotid artery. A group of 40 persons (19 healthy and 21 with hypertension and/or atherosclerosis) aged 22 to 81 were diagnosed by means of ultrasound. A high correlation occurred between the wall stiffness coefficient [alpha] and the intima-media thickness (r=0.950, p<0.00001)

5

Common carotid wall elasticity and intima-media thickness examinations by means of ultrasound

51%

Powałowski T. , Hilgertner L. , Trawiński Z.

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tom Vol. 1

343--346

EN

The aim of this study was to examine the relation between the intima-media thickness and the wall elasticity in the common carotid artery. A group of 40 persons (19 healthy and 21 with hypertension and/or atherosclerosis) aged 22 to 81 were diagnosed by means of ultrasound. A high correlation occurred between the wall stiffness coefficient α and the intima-media thickness (r = 0.950, p<0.001).

6

Ultradźwiękowe badanie wejściowej impedancji w modelach rozgałęzienia tętnicy szyjnej wspólnej

51%

Powałowski T. , Kałużyński K. , Trawiński Z. , Leśniak B.

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tom Vol. 83, nr 27

355-360

EN

The paper presents the setup and the results of examinations of the input impedance in the silicon models of the common carotid artery bifurcation without stenosis and with 90 % stenosis of the internal carotid artery branch. The input impedance measured in the models is compared with impedance calculated on the base of the values of the hydraulic model elements and of the model load. As a criterion of determination is used the difference between the measured flow and the flow evaluated on the basis on the calculated impedance in the carotid artery bifurcation models. There was no significant difference between the measured and calculated input impedances in the ease of the non-stenosed internal carotid artery. A significant difference between measured and calculated impedances was found for the model of bifurcation with the stenosis of the internal carotid artery. Reflections of pressure wave from the stenosis are expected to be the reason of this effect.