Robert Olszewski, Ph.D., Dr. Habil.

Department of Ultrasound (ZU)
Division of Ultrasonic Introscopy (PIU)
position: specialist
e-mail: rolsze

Recent publications
1.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, 2015
Abstract:

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.

Keywords:

Computed tomography, Echocardiography, Left ventricle, Speckles tracking, Strain, Ultrasound phantoms

Affiliations:
Trawiński Z.-IPPT PAN
Wójcik J.-IPPT PAN
Nowicki A.-IPPT PAN
Olszewski R.-other affiliation
Balcerzak A.-IPPT PAN
Frankowska E.-Military Medical Institute (PL)
Zegadło A.-other affiliation
Rydzyński P.-other affiliation
2.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, 2014
Abstract:

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%.

Affiliations:
Trawiński Z.-IPPT PAN
Wójcik J.-IPPT PAN
Nowicki A.-IPPT PAN
Balcerzak A.-IPPT PAN
Olszewski R.-other affiliation
Frankowska E.-Military Medical Institute (PL)
Zegadło A.-other affiliation
Rydzyński P.-other affiliation
3.Trawiński Z., Wójcik J., Nowicki A., Olszewski R., Dynamic Ultrasonic Model of Left Ventricle, HYDROACOUSTICS, ISSN: 1642-1817, Vol.16, pp.231-236, 2013
Abstract:

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.

Keywords:

soft tissue, phantom, ultrasound

Affiliations:
Trawiński Z.-IPPT PAN
Wójcik J.-IPPT PAN
Nowicki A.-IPPT PAN
Olszewski R.-other affiliation
4.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, 2012
Abstract:

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.

Keywords:

left ventricle, echocardiography, speckle modeling, ultrasound phantoms, strain, strain rate

Affiliations:
Olszewski R.-other affiliation
Trawiński Z.-IPPT PAN
Wójcik J.-IPPT PAN
Nowicki A.-IPPT PAN
5.Secomski W., Nowicki A., Tortoli P., Olszewski R., Multigate Doppler measurements of ultrasonic attenuation and blood hematocrit in human arteries, ULTRASOUND IN MEDICINE AND BIOLOGY, ISSN: 0301-5629, DOI: 10.1016/j.ultrasmedbio.2008.08.009, Vol.35, No.2, pp.230-236, 2009
Abstract:

A clinically applicable method for noninvasive measurement of hematocrit based on 20 MHz multigate Doppler ultrasound was developed. The ultrasound attenuation coefficient in blood is obtained by measuring the power of the signal coming from gates at different depths. A robust averaging method is introduced, which provides stable and repeatable results by using the echo signals from all depths inside the vessel. In vitro measurements have been done on porcine blood with hematocrit ranging from 3.0% to 65.0%. Steady and pulsatile flow conditions have been simulated using a peristaltic pump. The attenuation coefficient indicated the linear relation to hematocrit. The resulting correlation coefficient was R=0.999 for the continuous blood flow and R=0.992 for pulsatile flow. In vivo measurements have been performed in the brachial artery in 43 patients with hematocrit in the range of 32.0% to 49.3%. The mean absolute error has been 3.24% with a standard deviation of 3.72%.

Keywords:

blood, hematocrit, Doppler, ultrasonic attenuation

Affiliations:
Secomski W.-IPPT PAN
Nowicki A.-IPPT PAN
Tortoli P.-other affiliation
Olszewski R.-other affiliation

Conference papers
1.Nowicki A., Secomski W., Trawiński Z., Lewandowski M., Olszewski R., Estimation of Flow Mediated Vasodilation of the Radial Artery, IUS 2015, IEEE International Ultrasonics Symposium, 2015-10-21/10-24, Taipei (TW), DOI: 10.1109/ULTSYM.2015.0392, pp.1-4, 2015
Abstract:

Preceding atherosclerosis is endothelial dysfunction. There is therefore interest in the application of non-invasive clinical tools to assess endothelial function. There are commercially available ultrasound scanners to measure flow-mediated vasodilatation (FMD) of the brachial artery using 10-12 MHz linear array probes, however the attainable precision in estimating the changes in artery dilation does not exceeds 0.2 mm, far beyond the required one. We have introduced a high frequency scanning schemes 25-35MHz encoded (Golay) wobbling type imaging without Doppler (uScan developed in our lab, thick film wide bandwidth transducer, 50 microns axial resolution) and 20 MHz ultrasound (Ultrasonix) with 20 MHz pulsed Doppler attached to the linear array. The FMD results were normalized using AUC of shear rate at the radial artery wall.

Keywords:

thick-film transducers, flow-mediated vasolidation, radial artery, shear rate

Affiliations:
Nowicki A.-IPPT PAN
Secomski W.-IPPT PAN
Trawiński Z.-IPPT PAN
Lewandowski M.-IPPT PAN
Olszewski R.-other affiliation
2.Trawiński Z., Wójcik J., Nowicki A., Balcerzak A., Olszewski R., Frankowska E., Zegadło A., Rydzyński P., Evaluation of Left Ventricle Phantom by Ultrasound and Multislices Computer Tomography Imaging, FA2014, 7th FORUM ACUSTICUM 2014, 2014-09-07/09-12, Kraków (PL), No.R24_4, pp.1-5, 2014
Abstract:

The main goal of this study was to verify the suitability of sonographic model of the left ventricle (LV) in Computed Tomography (CT) environment and compare radial strain calculations obtained by two different techniques: speckle tracking ultrasonography and 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. During cycle of the pump, the Stroke Volume (SV) of water was pumped into the LV phantom and returned to the pump, resulting in changing the inner and outer diameters of the phantom. The stroke volume was set at of 24ml. The fluid pressure was changed within range of 0-60 mmHg, and the pulse rate was equal 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%.

Affiliations:
Trawiński Z.-IPPT PAN
Wójcik J.-IPPT PAN
Nowicki A.-IPPT PAN
Balcerzak A.-IPPT PAN
Olszewski R.-other affiliation
Frankowska E.-Military Medical Institute (PL)
Zegadło A.-other affiliation
Rydzyński P.-other affiliation

Conference abstracts
1.Nowicki A., Lewandowski M., Trots I., Olszewski R., High Frequency Thick Film Ultrasonic Transducers Used for Estimation of Flow-Mediated Vasodilation of the Radial Artery, SENSORDEVICES 2015, 6th International Conference on Sensor Device Technologies and Applications, 2015-08-23/08-28, Wenecja (IT), pp.99-100, 2015
Abstract:

Preceding atherosclerosis is an endothelial dysfunction. Therefore there is a growing interest in the application of non - invasive clinical tools to assess endothelial function. Commercially available ultrasound machines can measure flow - mediated vasodilatation of the brachial artery using maximum 10-12 MH z linear probes. The higher the probe frequency, the better the axial resolution. Recently, a new technology of piezoelectric transducers based on PZT thick film technology has been developed in Meggitt (Denmark) as a response to a call for devices working at higher frequencies. The thick films exhibited at least 30% bandwidth broadening comparing to the standard PZ 27 transducers, resulting in an increase in match filtering encoding output by a factor of 1.4 - 1.5 and finally resulting in a signal to noise gain of the same order. The introduction of a high frequency 25 - 30 MHz ultrasound scanner to measure radial artery diameter after reactive hyperemia open s a new window for more precise imaging of endothelial function.

Keywords:

thick film transducers, atherosclerosis, flow mediated vaso dilation

Affiliations:
Nowicki A.-IPPT PAN
Lewandowski M.-IPPT PAN
Trots I.-IPPT PAN
Olszewski R.-other affiliation
2.Secomski W., Olszewski R., Bilmin K., Nowicki A., Kujawska T., Grieb P., Terapeutyczne wykorzystanie ultradźwięków – wspomaganie procesu rozpuszczania skrzeplin oraz stymulacja apoptozy komórek nowotworowych, XIX Krajowa Konferencja Biocybernetyka i Inżynieria Biomedyczna, 2015-10-14/10-16, Warszawa (PL), pp.59, 2015
Abstract:

Ultradźwięki są stosowane w medycynie zarówno w diagnostyce - ultrasonografii jak i w terapii. Działanie terapeutyczne sprowadza się do efektów termicznych, uśmiercania komórek przez apoptozę oraz efektów sonomechanicznych. Terapie in-vivo są poprzedzane testami in-vitro komórek umieszczonych na szalce Petriego. W tej pracy zostaną przedstawione dwa efekty oddziaływania fali akustycznej na komórki: wspomaganie rozpuszczania skrzepliny oraz apoptoza komórek nowotworowych.
Do badań przygotowano zbiornik wypełniony odgazowaną wodą destylowaną z termostatem i mieszadłem elektromagnetycznym. W zbiorniku umieszczono płaski przetwornik ultradźwiękowy, promieniujący do góry, w kierunku zanurzonej w wodzie szalki Petriego ze skrzepliną lub komórkami.
W pierwszej części oddziaływano falą ultradźwiękową o częstotliwości 1.0 MHz i natężeniu Isata = 0.2 W/cm2 na skrzeplinę uzyskaną z kropli krwi 30 min po pobraniu. Skrzeplinę umieszczono w roztworze soli fizjologicznej z dodatkiem leku rozpuszczającego skrzeplinę tPA typu Actilyse 50 w stężeniu 10μg/ml i nadźwiękawiano przez 20 min. Eksperyment powtórzono z kolejnymi skrzeplinami stosując same ultradźwięki oraz sam lek Actilyse. Współdziałanie leku i fali ultradźwiękowej w ciągu 20 min spowodowało całkowite rozpuszczenie skrzepliny. W pozostałych przypadkach skrzeplina pozostała zmniejszając swoją objętość o 10-20%.
W drugiej części badano wpływ fali ultradźwiękowej 1.0 MHz na komórki nowotworowe szczurzego glejaka C6. Komórki wysiano na dnie szalki i hodowano w pożywce DMEM w temperaturze 37ºC. Następnie do pożywki dodano 1mM kwasu 5-aminolewulinowego ALA. Po 24h inkubacji, komórki poddano działaniu ultradźwięków o natężeniu Isata = 0.4, 0.8 oraz 1.2 W/cm2 przez 3 min. Po kolejnych 24h, żywotność komórek zbadano spektrofotometrem po dodaniu do pożywki odczynnika MTT assay. Badania powtórzono dla komórek bez ALA oraz bez ultradźwięków. Dla natężenia Isata = 1.2 W/cm2, żywotność komórek wynosiła 39% dla współdziałania ALA i ultradźwięków, 78% dla ALA oraz 99% dla ultradźwięków.
Przygotowane przez autorów stanowisko pomiarowe umożliwia prowadzenie badań in-vitro nad terapeutycznym oddziaływaniu ultradźwięków na komórki. Uzyskano pozytywne rezultaty w wykorzystaniu ultradźwięków zarówno do rozpuszczania skrzeplin – sonotrombolizy jak i uśmiercania komórek nowotworowych – terapii sonodynamicznej. Stosowano ultradźwięki małej mocy, niepowodujące zniszczenia komórek przez przegrzanie lub kawitację.

Keywords:

ultradźwięki terapeutyczne, sonotromboliza, tromboliza, leczenie nowotworów

Affiliations:
Secomski W.-IPPT PAN
Olszewski R.-other affiliation
Bilmin K.-Mossakowski Medical Research Centre, Polish Academy of Sciences (PL)
Nowicki A.-IPPT PAN
Kujawska T.-IPPT PAN
Grieb P.-Mossakowski Medical Research Centre, Polish Academy of Sciences (PL)
3.Frankowska E., Trawiński Z., Zegadło A., Olszewski R., Nowicki A., Bogusławska R., Assessment of radial strain in ultrasonographic model of left ventricle using speckle tracking ultrasound technique and multislice computed tomography, ECR 2014, European Congress of Radiology, 2014-03-06/03-10, Wiedeń (AT), DOI: 10.1594/ecr2014/C-0473, Vol.C-0473, pp.1-7, 2014
Abstract:

The aim of this study was to verify suitability of sonographic model of LV (left ventricle) in CT (computed tomography) environment and to compare in vitro radial strain calculations obtained by two different techniques: speckle tracking ultrasonography and multislice CT.

Affiliations:
Frankowska E.-Military Medical Institute (PL)
Trawiński Z.-IPPT PAN
Zegadło A.-other affiliation
Olszewski R.-other affiliation
Nowicki A.-IPPT PAN
Bogusławska R.-Military Medical Institute (PL)