1. |
Nowicki A., Gambin B., Secomski W., Trawiński Z., Szubielski M.^{♦}, Olszewski R., Does flow-mediated dilation normalization for base-scaled shear rate improve its value in coronary artery disease?,
ULTRASOUND IN MEDICINE AND BIOLOGY, ISSN: 0301-5629, DOI: 10.1016/j.ultrasmedbio.2020.05.018, Vol.46, No.9, pp.2551-2555, 2020Streszczenie: The article presents a new normalization of flow-mediated dilation (FMD) in the radial artery, taking into account the parameter BSSR being equal to the ratio of the basal shear rate (BS) measured before the cuff inflation and post occlusive shear rate (SR). The in vivo usefulness of the new normalization algorithm wasevaluated in two groups of patients. In group I, comprising 15 healthy volunteers, the normalized FMD/SR was(3.19 ± 1.4)*10^-4, while in group II, comprising 13 patients with stable coronary artery disease (CAD), it was(1.02 ± 0.76)*10^-4. We calculated almost 50% larger difference between the average values after normalizing FMD/BSSR. Specifically, the FMD/BSSR was equal to 28 ± 9.40 in group I and 6.01 ± 3.74 in group II. The prediction of CAD patients based on FMD/SR values had a sensitivity of 83.3% and a specificity of 84.6%, whereas the prediction of CAD patients based on the FMD/BSSR values revealed 100% sensitivity and specificity. These results confirm the usefulness of the novel normalization algorithm of the FMD in differentiation of normal patients from those with stable CAD. Słowa kluczowe: flow-mediated vasodilation, radial artery, shear rate, pulsed Doppler, ultrasonography, coronary artery disease
Afiliacje autorów:
Nowicki A. | - | IPPT PAN | Gambin B. | - | IPPT PAN | Secomski W. | - | IPPT PAN | Trawiński Z. | - | IPPT PAN | Szubielski M. | - | Mazovia Regional Hospital in Siedlce (PL) | Olszewski R. | - | IPPT PAN |
| | 70p. |
2. |
Nowicki A., Gambin B., Secomski W., Trawiński Z., Szubielski M.^{♦}, Tymkiewicz R., Olszewski R.^{♦}, Assessment of high frequency imaging and Doppler system for the measurements of the radial artery flow-mediated dilation,
ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.24425/aoa.2019.129276, Vol.44, No.4, pp.637-644, 2019Streszczenie: In the article we describe the new, high frequency, 20 MHz scanning/Doppler probe designed to measure the flow mediated dilation (FMD) and shear rate (SR) close to the radial artery wall. We compare two US scanning systems, standard vascular modality working below 12 MHz and high frequency 20 MHz system designed for FMD and SR measurements. Axial resolutions of both systems were compared by imaging of two closely spaced food plastic foils immersed in water and by measuring systolic/diastolic diameter changes in the radial artery. The sensitivities of Doppler modalities were also determined. The diagnostic potential of a high frequency system in measurements of FMD and SR was studied in vivo, in two groups of subjects, 12 healthy volunteers and 14 patients with stable coronary artery disease (CAD). Over three times better axial resolution was demonstrated for a high frequency system. Also, the sensitivity of the external single transducer 20 MHz pulse Doppler proved to be over 20 dB better (in terms of a signal-to-noise ratio) than the pulse Doppler incorporated into the linear array. Statistically significant differences in FMD and FMD/SR values for healthy volunteers and CAD patients were confirmed, p-values < 0:05. The areas under Receiver Operating Characteristic (ROC) curves for FMD and FMD/SR for the prediction CAD had the values of 0.99 and 0.97, respectively. These results justify the usefulness of the designed high-frequency scanning system to determine the FMD and SR in the radial artery as predictors of coronary arterial disease. Słowa kluczowe: low mediated dilation, shear rate, axial resolution, elevation resolution, pulsed Doppler, ultrasonic imaging Afiliacje autorów:
Nowicki A. | - | IPPT PAN | Gambin B. | - | IPPT PAN | Secomski W. | - | IPPT PAN | Trawiński Z. | - | IPPT PAN | Szubielski M. | - | Mazovia Regional Hospital in Siedlce (PL) | Tymkiewicz R. | - | IPPT PAN | Olszewski R. | - | inna afiliacja |
| | 70p. |
3. |
Nowicki A., Trawiński Z., Gambin B., Secomski W., Szubielski M.^{♦}, Parol M.^{♦}, Olszewski R., 20-MHZ ultrasound for measurements offlow-mediated dilation and shear rate in the radialartery,
ULTRASOUND IN MEDICINE AND BIOLOGY, ISSN: 0301-5629, DOI: 10.1016/j.ultrasmedbio.2018.02.011, Vol.44, No.6, pp.1187-1197, 2018Streszczenie: A high-frequency scanning system consisting of a 20-MHz linear array transducer combined with a 20-MHz pulsed Dopplerprobe was introduced to evaluate the degree of radial artery ﬂow-mediated dilation (FMD [%]) in two groups of patients after5 min of controlled forearm ischemia followed by reactive hyperemia. In group I, comprising 27 healthy volunteers, FMD (mean ± standard deviation) was 15.26 ± 4.90% (95% confidence interval [CI]: 13.32%–17.20%); in group II, comprising 17 patients with chronic coronary artery disease, FMD was significantly less at 4.53 ± 4.11% (95% CI: 2.42%–6.64%). Specifically, the ratio FMD/SR (mean ± standard deviation),wasequalto5.36×10−4±4.64×10−4 (95%CI:3.54×10−4 to7.18×10−4)ingroupIand1.38×10−4±0.89×10−4 (95% CI: 0.70 × 10−4 to 2.06 × 10−4) in group II. Statistically significant differences between the two groups were confirmed by a Wilcoxon–Mann–Whitney test for both FMD and FMD/SR (p < 0.01). Areas under receiver operating characteristic curves for FMD and FMD/SR were greater than 0.9. The results confirm the usefulness of the proposed measurements of radial artery FMD and SR in differentiation of normal patients from those with chronic coronary artery disease. (E-mail: ) © 2018 World Federation for Ultrasound in Medicine & Biology. All rights reserved. Słowa kluczowe: Flow-mediated vasodilation, Radial artery, Shear rate, Reactive hyperemia, Endothelium, Pulsed doppler, Ultrasonography Afiliacje autorów:
Nowicki A. | - | IPPT PAN | Trawiński Z. | - | IPPT PAN | Gambin B. | - | IPPT PAN | Secomski W. | - | IPPT PAN | Szubielski M. | - | Mazovia Regional Hospital in Siedlce (PL) | Parol M. | - | The John Paul’s II Western Hospital in Grodzisk Mazowiecki (PL) | Olszewski R. | - | IPPT PAN |
| | 40p. |
4. |
Nowicki A., Secomski W., Trawiński Z., Lewandowski M., Trots I., Szubielski M.^{♦}, Olszewski R., Estimation of radial artery reactive response using high frequency ultrasound,
HYDROACOUSTICS, ISSN: 1642-1817, Vol.19, pp.297-306, 2016Streszczenie: Background:
There is a growing interest in the application of non-invasive clinical tools allowing one to assess the endothelial function, preceding atherosclerosis. The precision in estimating of the artery Flow Mediated Vasodilation (FMD) using standard 10-12 MHz linear array probes does not exceed 0.2 mm, far beyond that required.
Methods:
We have introduced a wide-band, high frequency 25-30 MHz, Golay encoded wobbling type imaging to measure dilation of the radial artery instead of the brachial one. 18 young volunteers, and 4 volunteers with cardiac events history, were examined. In the second approach 20 MHz linear scanning combined with 20 MHz pulsed Doppler attached to the linear array was used. The radial artery FMD was normalized using shear rate at the radial artery wall.
Results and Conclusions:
For the “healthy” group, the FMD resulting from reactive hyperemia response was over 20%; while in the “atherosclerotic” group, the FMD was at least twice as small, not exceeding 10%. The shear rate (SR) normalized FMDSR was in the range from 7.8 to 9.9 in arbitrary units, while in patients with minor cardiac history FMDSR was clearly lower, 6.8 to 7.6. The normalized FMDSR of radial artery RARR can be an alternative to the brachial FMD where the precision of measurements is lower and the diameter dilation does not exceed 7-10%. Słowa kluczowe: thick film transducers, atherosclerosis, flow mediated vasodilation Afiliacje autorów:
Nowicki A. | - | IPPT PAN | Secomski W. | - | IPPT PAN | Trawiński Z. | - | IPPT PAN | Lewandowski M. | - | IPPT PAN | Trots I. | - | IPPT PAN | Szubielski M. | - | Mazovia Regional Hospital in Siedlce (PL) | Olszewski R. | - | IPPT PAN |
| | 6p. |
5. |
Trawiński Z., Wójcik J., Nowicki A., Olszewski R.^{♦}, Balcerzak A., Frankowska E.^{♦}, Zegadło A.^{♦}, Rydzyński P.^{♦}, Strain examinations of the left ventricle phantom by ultrasound and multislices computed tomography imaging,
Biocybernetics and Biomedical Engineering, ISSN: 0208-5216, DOI: 10.1016/j.bbe.2015.03.001, Vol.35, pp.255-263, 2015Streszczenie: The main aim of this study was to verify the suitability of the hydrogel sonographic model of the left ventricle (LV) in the computed tomography (CT) environment and echocardiography and compare the radial strain calculations obtained by two different techniques: the speckle tracking ultrasonography and the multislices computed tomography (MSCT). The measurement setup consists of the LV model immersed in a cylindrical tank filled with water, hydraulic pump, the ultrasound scanner, hydraulic pump controller, pressure measurement system of water inside the LV model, and iMac workstation. The phantom was scanned using a 3.5 MHz Artida Toshiba ultrasound scanner unit at two angle positions: 0° and 25°. In this work a new method of assessment of RF speckles’ tracking. LV phantom was also examined using the CT 750 HD 64-slice MSCT machine (GE Healthcare). The results showed that the radial strain (RS) was independent on the insonifying angle or the pump rate. The results showed a very good agreement, at the level of 0.9%, in the radial strain assessment between the ultrasound M-mode technique and multislice CT examination. The study indicates the usefulness of the ultrasonographic LV model in the CT technique. The presented ultrasonographic LV phantom may be used to analyze left ventricle wall strains in physiological as well as pathological conditions. CT, ultrasound M-mode techniques, and author's speckle tracking algorithm, can be used as reference methods in conducting comparative studies using ultrasound scanners of various manufacturers. Słowa kluczowe: Computed tomography, Echocardiography, Left ventricle, Speckles tracking, Strain, Ultrasound phantoms Afiliacje autorów:
Trawiński Z. | - | IPPT PAN | Wójcik J. | - | IPPT PAN | Nowicki A. | - | IPPT PAN | Olszewski R. | - | inna afiliacja | Balcerzak A. | - | IPPT PAN | Frankowska E. | - | Military Medical Institute (PL) | Zegadło A. | - | inna afiliacja | Rydzyński P. | - | inna afiliacja |
| | 15p. |
6. |
Trawiński Z., Wójcik J., Nowicki A., Balcerzak A., Olszewski R.^{♦}, Frankowska E.^{♦}, Zegadło A.^{♦}, Rydzyński P.^{♦}, Assessment of left ventricle phantom wall compressibility by ultrasound and computed tomography methods,
HYDROACOUSTICS, ISSN: 1642-1817, Vol.17, pp.211-218, 2014Streszczenie: The present work concerns the sonographic model of the left ventricle (LV) examined in the Computed Tomography (CT) environment and compare radial strain calculations obtained by two different techniques: the speckle tracking ultrasonography and the Multislices Computed Tomography (MSCT). The Left Ventricular (LF) phantom was fabricated from 10% solution of the poly(vinyl alcohol) (PVA). Our model of the LV was driven by the computer- controlled hydraulic piston Super -Pump (Vivitro Inc., Canada) with adjustable fluid volumes. The stroke volume was set at of 24ml. The fluid pressure was changed within range of 0- 60 mmHg, and the pulse rate was of 60 cycles/per minute. The relationships between computer controlled left ventricular wall deformations and its visual izations of the echocardiographic and CT imaging, both in the normal and pathological conditions were examined. The difference of assessment the Radial Strain between two methods was not exceeding 1.1%. Afiliacje autorów:
Trawiński Z. | - | IPPT PAN | Wójcik J. | - | IPPT PAN | Nowicki A. | - | IPPT PAN | Balcerzak A. | - | IPPT PAN | Olszewski R. | - | inna afiliacja | Frankowska E. | - | Military Medical Institute (PL) | Zegadło A. | - | inna afiliacja | Rydzyński P. | - | inna afiliacja |
| | 7p. |
7. |
Trawiński Z., Wójcik J., Nowicki A., Olszewski R.^{♦}, Dynamic Ultrasonic Model of Left Ventricle,
HYDROACOUSTICS, ISSN: 1642-1817, Vol.16, pp.231-236, 2013Streszczenie: Two different tissue phantoms of the left ventricle to imitate a beating left ventricle were developed: first was prepared using a sponge material and second phantom was constructed using a polyvinyl alcohol material modeled into a homogeneous hollow cylinder: approximately 10 cm and 12 cm in length for the first and second phantom, respectively. Both phantoms were 5 cm in diameter, with a wall thickness of 1.0 cm. Additionally, a small part of the wall of the second phantom was processed to simulate the stiffness of myocardial infarction. The phantoms were connected at the end to an adjustable external pump. The pulse volume inside the cylinder was set between 12 to 50 ml at rates of 40, 60, 100, 120 beats/minute. The phantoms were immersed in water for ultrasound scanning with two different insonation angles (90 and 65 degrees). Strain and strain rate were measured with different combinations of angles and pulse rates. The main aim of this work was to develop the new method for validation of the human infarct wall strain calculation procedures using the speckles tracking. Słowa kluczowe: soft tissue, phantom, ultrasound Afiliacje autorów:
Trawiński Z. | - | IPPT PAN | Wójcik J. | - | IPPT PAN | Nowicki A. | - | IPPT PAN | Olszewski R. | - | inna afiliacja |
| | 7p. |
8. |
Trawiński Z., Hilgertner L.^{♦}, Lewin P.A.^{♦}, Nowicki A., Ultrasonically assisted evaluation of the impact of atherosclerotic plaque on the pulse pressure wave propagation: A clinical feasibility study,
Ultrasonics, ISSN: 0041-624X, DOI: 10.1016/j.ultras.2011.10.010, Vol.52, pp.475-481, 2012Streszczenie: The purpose of this work was to evaluate ultrasound modality as a non-invasive tool for determination of impact of the degree of the atherosclerotic plaque located in human internal carotid arteries on the values of the parameters of the pulse wave. Specifically, the applicability of the method to such arteries as brachial, common, and internal carotid was examined. The method developed is based on analysis of two characteristic parameters: the value of the mean reflection coefficient modulus |Γ|a of the blood pressure wave and time delay Δt between the forward (travelling) and backward (reflected) blood pressure waves. The blood pressure wave was determined from ultrasound measurements of the artery’s inner (internal) diameter, using the custom made wall tracking system (WTS) operating at 6.75 MHz. Clinical data were obtained from the carotid arteries measurements of 70 human subjects. These included the control group of 30 healthy individuals along with the patients diagnosed with the stenosis of the internal carotid artery (ICA) ranging from 20% to 99% or with the ICA occlusion. The results indicate that with increasing level of stenosis of the ICA the value of the mean reflection coefficient measured in the common carotid artery, significantly increases from |Γ|a = 0.45 for healthy individuals to |Γ|a = 0.61 for patients with stenosis level of 90–99%, or ICA occlusion. Similarly, the time delay Δt decreases from 52 ms to 25 ms for the respective groups. The method described holds promise that it might be clinically useful as a non-invasive tool for localization of distal severe artery narrowing, which can assist in identifying early stages of atherosclerosis especially in regions, which are inaccessible for the ultrasound probe (e.g. carotid sinus or middle cerebral artery). Słowa kluczowe: Pulse wave, Ultrasound, Vascular impedance, Stenosis Afiliacje autorów:
Trawiński Z. | - | IPPT PAN | Hilgertner L. | - | Medical University of Warsaw (PL) | Lewin P.A. | - | Drexel University (US) | Nowicki A. | - | IPPT PAN |
| | 25p. |
9. |
Olszewski R.^{♦}, Trawiński Z., Wójcik J., Nowicki A., Mathematical and Ultrasonographic Model of the Left Ventricle:in Vitro Studies,
ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, Vol.37, No.4, pp.583-595, 2012Streszczenie: The main objective of this study is to develop an echocardiographic model of the left ventricular and numerical modeling of the speckles- markers tracking in the ultrasound (ultrasonographic) imaging of the left ventricle. The work is aimed at the creation of controlled and mobile environment that enables to examine the relationships between left ventricular wall deformations and visualizations of these states in the form of echocardiographic imaging and relations between the dynamically changing distributions of tissue markers of studied structures. Słowa kluczowe: left ventricle, echocardiography, speckle modeling, ultrasound phantoms, strain, strain rate Afiliacje autorów:
Olszewski R. | - | inna afiliacja | Trawiński Z. | - | IPPT PAN | Wójcik J. | - | IPPT PAN | Nowicki A. | - | IPPT PAN |
| | 15p. |
10. |
Trawiński Z., Two-point method for arterial local pulse wave velocity measurement by means of ultrasonic RF signal processing,
ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, Vol.35, No.1, pp.3-11, 2010Streszczenie: The aim of this paper is to describe a non-invasive method of examination of the local pulse wave velocity. The measurements were carried out in the model of the artery immersed in a water tank. Two synchronized ultrasonic apparatus VED with the ultrasonic radio frequency echoes acquisition system were used for evaluation of the arterial elasticity. The zero-crossing method was used for determination of the diameter changes of the artery model. The transit time between the waveforms of instant artery diameter was measured at two points of the artery model, separated by the distance of 5 cm. The transit time was determined using the criteria of similarity of the first derivatives of the raising slopes of the curves describing instant vessel's diameter changes. The pulse wave velocity obtained by the proposed two-point method was compared with the results obtained by the one-point method based on the modified Bramwell-Hill relation. Słowa kluczowe: ultrasound, local pulse wave velocity, model of artery Afiliacje autorów:
| | 9p. |
11. |
Trawiński Z., Powałowski T., Wójcik J., Gutkiewicz P., Ultrasonic non-invasive method for relative changes measurements of IMT in common carotid artery wall,
ACTA PHYSICA POLONICA A, ISSN: 0587-4246, DOI: 10.12693/APhysPolA.114.A-243, Vol.114, pp.A241-A246, 2008Streszczenie: The aim of this paper is to present the new method for relative changes measurements of intima-media thickness in the common carotid artery wall. The numerical solver was created for calculation of the fields of ultrasonic beams and scattered fields under different boundary conditions and different angles of penetration of ultrasonic beams with respect to the position of the arterial wall. The cylindrical model of the artery was changing the radius and thickness of the wall under cyclic variation of blood pressure. The presented method was verified on a pipe made of latex. The paper describes also the initial results of examinations of the intima-media thickness. The good agreement for the angle dependence and the perpendicular ultrasonic beam displacement from the longitudinal axis of the artery segment between the numerical calculation and experimental results was obtained for different artery diameters. Afiliacje autorów:
Trawiński Z. | - | IPPT PAN | Powałowski T. | - | IPPT PAN | Wójcik J. | - | IPPT PAN | Gutkiewicz P. | - | IPPT PAN |
| |
12. |
Trawiński Z., Wójcik J., Powałowski T., Gutkiewicz P., Ultrasonic Non-Invasive Method for Relative Changes Measurements of Intima-Media Thickness in Artery Walls,
ACTA PHYSICA POLONICA A, ISSN: 0587-4246, Vol.114, No.6-A, pp.A-243-247, 2008 | |
13. |
Wójcik J., Powałowski T., Trawiński Z., Numerical simulation and experimental results of ultrasonic waves scattering on a model of the artery,
EUROPEAN PHYSICAL JOURNAL SPECIAL TOPICS, ISSN: 1951-6355, DOI: 10.1140/epjst/e2008-00554-9, Vol.154, pp.249-252, 2008Streszczenie: The aim of this paper is to compare the results of the mathematical modeling and experimental results of the ultrasonic waves scattering in the inhomogeneous dissipative medium. The research was carried out for an artery model (a pipe made of a latex), with internal diameter of 5 mm and wall thickness of 1.25 mm. The numerical solver was created for calculation of the fields of ultrasonic beams and scattered fields under different boundary conditions, different angles and transversal displacement of ultrasonic beams with respect to the position of the arterial wall. The investigations employed the VED ultrasonic apparatus. The good agreement between the numerical calculation and experimental results was obtained. Słowa kluczowe: Model of the artery, scattering, numerical solver Afiliacje autorów:
Wójcik J. | - | IPPT PAN | Powałowski T. | - | IPPT PAN | Trawiński Z. | - | IPPT PAN |
| |
14. |
Trawiński Z., Wójcik J., Comparison of methods used for ultrasonic examinations of IMT in the wall of the carotid artery model,
ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, Vol.33, No.4S, pp.27-32, 2008Streszczenie: The aim of this paper is to compare the results of examinations of the intima-media thickness (IMT) in the wall of the carotid artery model by means of zero-crossing and correlation methods. The research was carried out on the elastic artery model (a pipe made of latex), with the internal diameter of 3, 5 and 8 mm and the wall thickness of 0.75, 1.25 and 2 mm. A numerical solver was created for the purpose of calculating the fields of ultrasonic beams and scattered fields under different boundary conditions, different angles and transversal displacements of ultrasonic beams in respect of the position of the arterial wall. A VED ultrasonic apparatus was used during the investigations. The frequency of the transmitted ultrasound was 6.75 MHz. The numerical solver was used for the creation of ultrasonic RF reference signals. A good conformity was obtained between changing the numerical reference of the IMT and the results of determining the IMT by both the zero-crossing method and the correlation method. Słowa kluczowe: ultrasound, carotid artery, intima-media thickness, numerical model Afiliacje autorów:
Trawiński Z. | - | IPPT PAN | Wójcik J. | - | IPPT PAN |
| |
15. |
Trawiński Z., New method for measure regional pulse wave velocity by means of RF ultrasonic signals,
MOLECULAR AND QUANTUM ACOUSTICS. ANNUAL JOURNAL, ISSN: 0208-5151, Vol.29, pp.163-169, 2008Streszczenie: The aim of this paper is to describe a non-invasive method of examination of the local pulse wave velocity. The measurements were carried out in the elastic silicon model of the artery immersed in water tank. Two synchronized ultrasonic apparatus VED with the ultrasonic radio frequency echoes acquisition for evaluation of the arterial elasticity, developed by the author, were used. The zerocrossing method was used for evaluating the pulse wave by measurements of the diameter changes of the model of the artery. The transit time between the waveforms of instant artery diameter at two measurement points, 5cm along the model of the artery was measured. The transit time was determined using the criteria of similarity of the first derivatives of the raising slopes of curves describing the instant vessel’s diameter changes in two measurement points of the model of the artery. The pulse wave velocity obtained by proposed two-point method was referred to the one-point method based of the modified Bramwell-Hill relation. Słowa kluczowe: ultrasound, local pulse wave velocity, model of artery Afiliacje autorów:
| |
16. |
Trawiński Z., Ultrasonic method for relative changes of intima-media thickness measurements in common carotid artery,
HYDROACOUSTICS, ISSN: 1642-1817, Vol.11, pp.411-418, 2008Streszczenie: This paper presents results of examinations of the intima-media thickness (IMT) in human common carotid arteries. Ultrasonic examinations were carried out on healthy volunteers with the use of the apparatus Vascular Echo Doppler (VED), designed in IFTR-PAS to measure the elasticity of arteries. Application of the PDA-14 PC-card (Signatec) allowed for the acquisition of ultrasonic RF signal from the output of the apparatus VED and for further analysis of dynamic changes of the IMT during a heart cycle. Changing of the IMT in time as a difference between the instantaneous position of the two tracking slopes of RF echoes was obtained. For this purpose the zero-crossing method, for tracking phase changes of two characteristic rising slopes of the RF ultrasonic echo, was used. Afiliacje autorów:
| |
17. |
Wójcik J., Trawiński Z., Powałowski T., Comparison of experimental results and numerical calculations of ultrasonic waves scattering on a model of the artery,
HYDROACOUSTICS, ISSN: 1642-1817, Vol.11, pp.449-458, 2008Streszczenie: The aim of this paper is to compare the results of the mathematical modeling and experimental results of the ultrasonic waves scattering in the inhomogeneous dissipative medium. The research was carried out for an artery model (a pipe made of a latex), with internal diameter of 3, 5 and 8 mm and wall thickness of 0.75, 1.25 and 2 mm. The numerical solver was created for calculation of the fields of ultrasonic beams and scattered fields under different boundary conditions, different angles and transversal displacement of ultrasonic beams with respect to the position of the arterial wall. The investigations employed the VED ultrasonic apparatus. The frequency of the transmitted ultrasound was 6.75 MHz. The good agreement between the numerical calculation and experimental results was obtained. The numerical solver is used for verified proposed methods for determining of the IMT in the artery walls. Słowa kluczowe: ultrasound, scatering, artery model, numerical calculations, eksperimental results, Comparison Afiliacje autorów:
Wójcik J. | - | IPPT PAN | Trawiński Z. | - | IPPT PAN | Powałowski T. | - | IPPT PAN |
| |
18. |
Powałowski T., Trawiński Z., Gutkiewicz P., Ultrasonic examinations of IMT changes in common carotid artery wall,
ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, Vol.32, No.4, pp.135-141, 2007Streszczenie: The paper describes the initial results of examinations of the intima-media thickness (IMT) in the common carotid artery wall. The examinations of the IMT enable the assessment of elastic properties of the arterial wall. Ultrasonic examinations were carried out on healthy volunteers with the use the apparatus Vascular Echo Doppler (VED), designed by the authors to measure the elasticity of arteries. Application of the PDA-14 PC-card (Signatec) allowed for the acquisition of ultrasonic RF signal from the output of the apparatus VED and further analysis of dynamic changes of the IMT during a heart cycle. Changing of the IMT in time as a difference between the instantaneous position of the two tracking slopes of RF echoes was obtained. For this purpose, the zero-crossing method for tracking the phase changes of the two rising slopes of the RF ultrasonic echo was used. Słowa kluczowe: ultrasound, common carotid artery, elasticity, intima-media thickness Afiliacje autorów:
Powałowski T. | - | IPPT PAN | Trawiński Z. | - | IPPT PAN | Gutkiewicz P. | - | IPPT PAN |
| |
19. |
Powałowski T., Wójcik J., Trawiński Z., Modelling of examinations of artery wall thickness changes,
ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, Vol.32, pp.851-858, 2007Streszczenie: The developed solver of acoustic field was used for simulation of the artery wall thickness examination. It is capable of describing spatial and time-dependent distribution of an ultrasonic beam, that is emitted by a piezoelectric ring transducer and then backscattered on cylindrical surfaces of the walls in artery models. The electrical signal received corresponds closely with the actual RF signal that is obtained during measurements at the output of the ultrasonicVED apparatus. The theoretical model of the artery for creating the ultrasonic reflected echoes was used. The internal radius of the artery model was 3mm for the diastolic pressure and 3.3mm for the systolic pressure. The intima- media thicknes (IMT) of the artery wall was changed from 0.48mm to 0.44mm respectively. The echoes-tracking solver based on the zero-crossing and correlation methods was used for detecting changes of the IMT. Słowa kluczowe: ultrasound, common carotid artery, elasticity, intima-media thickness, numerical solver Afiliacje autorów:
Powałowski T. | - | IPPT PAN | Wójcik J. | - | IPPT PAN | Trawiński Z. | - | IPPT PAN |
| |
20. |
Wójcik J., Powałowski T., Trawiński Z., Numerical analyze and experimental results of ultrasonic waves scattering on a model of the artery,
MOLECULAR AND QUANTUM ACOUSTICS. ANNUAL JOURNAL, ISSN: 0208-5151, Vol.28, pp.279-283, 2007 | |
21. |
Powałowski T., Wójcik J., Trawiński Z., Numerical solver of acoustic field in simulation of artery wall thickness examinations,
HYDROACOUSTICS, ISSN: 1642-1817, Vol.10, pp.123-168, 2007Streszczenie: 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 anultrasonic apparatus. The developed solver of acoustic field was used for simulation of the artery wall tickness examination. The theoretical model of the atrery for the creating the simulated ultrasonic reflected echoes was used. The internal radiusof the artery model was 3mm for the diastolic pressure and and 3.3mm for the systolic pressure. The intima-media thicknes (IMT) of the artery wall was changed from o.48 to 0.44 respectively. The solver based on zero-crossing method was used for detecting changes of the IMT. Słowa kluczowe: ultrasound, mathematical model, scatering, inhomogenous loosing medium, numerical simulations, intima-media changes Afiliacje autorów:
Powałowski T. | - | IPPT PAN | Wójcik J. | - | IPPT PAN | Trawiński Z. | - | IPPT PAN |
| |
22. |
Trawiński Z., Powałowski T., Modeling and ultrasonic examination of common carotid artery thickness changes,
ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, Vol.31, pp.29-34, 2006Streszczenie: The paper describes the initial results of numeric analysis of plane-strain of a model of the human common carotid artery. The results of computer modeling were compared with the experimental data obtained by means of ultrasonic measurements of the changes in the thickness of the common carotid artery wall. The ultrasonic examination was carried out on a 34 years old healthy male using the VED apparatus designed by the authors to measure the elasticity of arteries. The numeric analysis was made by means of the finite element method (FEM) using the MARC K7 programming of the Analysis Research Corporation based on the operating system UNIX. As a model of the common carotid artery the authors used a hollow cylinder made of the isotropic, homogeneous, almost incompressible material (Poisson’s constant ν=0.4999) having the Young’s module E=159.2 kPa and the combined thickness of the internal and middle layer IMT = 0.52 mm. The modeling of plane-strain concerned the effect of the change in the internal radius and the change in the cylinder wall thickness as a result of the static change of pressure inside the cylinder within the values of 0–45 mmHg. The study obtained satisfactory results in the computer simulation of the changes in the artery walls thickness. Słowa kluczowe: ultrasound, elasticity of the common carotid artery wall, wall thickness Afiliacje autorów:
Trawiński Z. | - | IPPT PAN | Powałowski T. | - | IPPT PAN |
| |
23. |
Wójcik J., Powałowski T., Tymkiewicz R., Lamers A.^{♦}, Trawiński Z., Scattering of ultrasonic wave on a model of the artery,
ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, Vol.31, pp.471-479, 2006Streszczenie: The study was aimed at elaboration of a mathematical model to describe the process of acoustic wave propagation in an inhomogeneous and absorbing medium, whereas the wave is generated by an ultrasonic probe. The modelling proces covered the phenomenon of ultrasonic wave backscattering on an elastic pipe with dimensions similar to the artery section. Later on the numerical codes were determined in order to calculate the fields of ultrasonic waves, as well as backscattered fields for various boundary conditions. Numerical calculations make it possible to definethe waveforms for electric signals that are produced when ultrasonic waves, being reflected and backsvattered by an artery model, are then received by the ultrasonic probe. It is the signalwhich pretty well corresponds with the actual RF signal that is obtained during measurements at the output of anultrasonic apparatus. Słowa kluczowe: ultrasound, backscattering, artery, numerical model Afiliacje autorów:
Wójcik J. | - | IPPT PAN | Powałowski T. | - | IPPT PAN | Tymkiewicz R. | - | IPPT PAN | Lamers A. | - | inna afiliacja | Trawiński Z. | - | IPPT PAN |
| |