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Wyszukujesz frazę "Olszewski, J." wg kryterium: Autor


Wyświetlanie 1-3 z 3
Tytuł:
Dynamic ultrasonic model of left ventricle
Autorzy:
Trawiński, Z.
Wójcik, J.
Nowicki, A.
Olszewski, R.
Powiązania:
https://bibliotekanauki.pl/articles/332195.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
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.
Źródło:
Hydroacoustics; 2013, 16; 231-236
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of absorption and scattering on the velocity of acoustic streaming
Autorzy:
Secomski, W.
Wójcik, J.
Klimonda, Z.
Olszewski, R.
Nowicki, A.
Powiązania:
https://bibliotekanauki.pl/articles/332699.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
ultrasound
radiation force
starch
contrast agent
blood
thrombolysis
Opis:
Streaming velocity depends on intensity and absorption of ultrasound in the media. In some cases, such as ultrasound scattered on blood cells at high frequencies, or the presence of ultrasound contrast agents, scattering affects the streaming speed. The velocities of acoustic streaming in a blood-mimicking starch suspension in water and Bracco BR14 contrast agent were measured. The source of the streaming was a plane 20MHz ultrasonic transducer. Velocity was estimated from the averaged Doppler spectrum. The single particle driving force was calculated as the integral of the momentum density tensor components. For different starch concentrations, the streaming velocity increased from 8.9 to 12.5mm/s. This corresponds to a constant 14% velocity increase for a 1 g/l increase in starch concentration. For BR14, the streaming velocity remained constant at 7.2mm/s and was independent of the microbubbles concentration. The velocity was less than in reference, within 0.5mm/s measurement error. Theoretical calculations showed a 16% increase in streaming velocity for 1 g/l starch concentration rise, very similar to the experimental results. The theory has also shown the ability to reduce the streaming velocity by low-density scatterers, as was experimentally proved using the BR14 contrast agent.
Źródło:
Hydroacoustics; 2017, 20; 159-168
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessment of left ventricle phantom wall compressibility by ultrasound and computed tomography methods
Autorzy:
Trawiński, Z.
Wójcik, J.
Nowicki, A.
Balcerzak, A.
Olszewski, R.
Frankowska, E.
Zegadło, A.
Rydzyński, P.
Powiązania:
https://bibliotekanauki.pl/articles/331815.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
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 fabricate 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 visualizations 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%.
Źródło:
Hydroacoustics; 2014, 17; 211-218
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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