Institute of Fundamental Technological Research
Polish Academy of Sciences

Staff

Piotr Karwat, PhD

Department of Ultrasound (ZU)
Division of Acoustic Microscopy (PMAk)
position: Assistant Professor
telephone: (+48) 22 826 12 81 ext.: 314
room: 522
e-mail:
ORCID: 0000-0002-2104-1130

Doctoral thesis
2017-11-30 Numeryczna rekonstrukcja pola prędkości fali akustycznej na podstawie analizy sygnałów ultradźwiękowych 
supervisor -- Jurij Tasinkiewicz, PhD, DSc, IPPT PAN
 

Recent publications
1.  Pawłowska A., Karwat P., Żołek N.S., Letter to the Editor. Re: "[Dataset of breast ultrasound images" by W. Al-Dhabyani, M. Gomaa, H. Khaled & A. Fahmy, Data in Brief, 2020, 28, 104863]", Data in Brief, ISSN: 2352-3409, DOI: 10.1016/j.dib.2023.109247, Vol.48C, pp.109247--, 2023

Abstract:
In an interesting article previously published in Data in Brief [Dataset of breast ultrasound images" by W. Al-Dhabyani, M. Gomaa, H. Khaled & A. Fahmy, Data in Brief, 2020, 28, 104863], the authors presented a dataset of breast ultrasound images containing lesions. As of April 22, 2023, this study has garnered significant attention from researchers, as evident by its 298 citations in Scopus data. This is unsurprising considering that the study presents one of the few publicly available datasets on breast ultrasound images, as well as binary masks highlighting the lesions. When implementing various aspects of explainable AI, we verify the correctness of the input data at every stage, especially when using various data sources. In an attempt to use this dataset for research, we did some exploration and identified some inconsistencies that could have a significant impact on the results of the studies utilizing them. As the role of tumor detection is indisputable we feel obliged to point attention to some aspects that need to be kept in mind while using this database in order to receive reliable and good quality results.

Affiliations:
Pawłowska A. - IPPT PAN
Karwat P. - IPPT PAN
Żołek N.S. - IPPT PAN
2.  Lewandowski M.J., Karwat P., Jarosik P., Rozbicki J., Walczak M., Smach H., A High-Speed Ultrasound Full-Matrix Capture Acquisition System for Robotic Weld Inspection, Research and Review Journal of Nondestructive Testing, ISSN: 2941-4989, DOI: 10.58286/28163, Vol.1, No.1, pp.1-6, 2023

Abstract:
Phased-Array Ultrasonic Technique is traditionally used for the non-destructive inspection of welds and supported by industrial-grade inspection equipment. FullMatrix Capture (FMC) with Total Focusing Method (TFM) provide new capabilities and multimodal imaging, but available commercial scanners have limitations in acquisition speed (30–300MB/s) and reconstruction speed. Our goal was to develop a solution for FMC acquisition that can be applied to high-speed robotized weld scanning (speed of 100 mm/s with a resolution of 1 mm). For FMC acquisition, we have applied a portable programmable ultrasound research system us4R-lite™ (us4us Ltd., Poland) in a 64:256 channel configuration and standard angled 32-element Phased-Array probes. The system can acquire and store raw RF or demodulated I/Q data at a speed of 2–6 GB/s, enabling real-time FMC at high speed. Data can be stored on a PC during scanning and processed by a high-performance GPU. We have successfully tested our experimental setup while scanning flat-section welds with a motorized scanner at a speed approaching 100 mm/s. The acquisition and processing software developed uses Nvidia CUDA on GPU and can manage real-time storage and scanning. Next, we are planning to integrate the solution into an industrialgrade high-speed FMC acquisition system with embedded GPU processing

Keywords:
Ultrasonic Testing (UT) (4285), robotic inspection (23), PAUT (42), FMC (16), TFM (28), GPU processing

Affiliations:
Lewandowski M.J. - other affiliation
Karwat P. - other affiliation
Jarosik P. - other affiliation
Rozbicki J. - other affiliation
Walczak M. - other affiliation
Smach H. - IPPT PAN
3.  Lewandowski M.J., Rozbicki J., Smach H., Karwat P., Szczurek A., Sala J., Bera A., Modelowe rozwiązania skanerów UTPA do badań spawów dla wież wiatrowych, sekcji płaskich oraz konstrukcji wielkogabarytowych on-shore/off-shore, BADANIA NIENISZCZĄCE I DIAGNOSTYKA, ISSN: 2451-4462, Vol.1-4, pp.97-100, 2023

Abstract:
W ramach realizowanego projektu wdrożeniowego (akronim: BalTECH, finansowanie NCBR POIR) opracowano modelowe stanowiska skanerów UTPA do badań nieniszczących spawów dla asortymentu produktów wytwarzanych w Baltic Operator sp. z o.o. Skanery zapewniają prowadzenie i sprzężenie dwóch głowic Phased-Array (badanie dwustronne). Do realizacji badań UTPA wykorzystano komercyjny aparat Olympus-OmniScan ™ X3, natomiast dla metody UTPA-FMC (Full-Matrix Capture) badawczą platformę ultradźwiękową us4R-lite™ firmy us4us sp. z o.o. Wykonano zestaw ok. 170 próbek testowych spawów z rożnymi niezgodnościami dla płyt w zakresie grubości 12–65 mm, które zostały przebadanie metodami VT, MT/PT, UT, RT, UTPA. Opracowana procedura badania i wzorce testowe pozwoliły na pełną walidację klasycznej metody UTPA do badania sekcji wież wiatrowych. Eksperymentalne zastosowanie i porównanie metody UTPA-FMC pokazało jej duży potencjał oraz nowe możliwości wizualizacji i oceny wad, w stosunku do klasycznej metody UTPA. Zweryfikowano także możliwość zbierania surowych danych FMC z prędkością do 100 mm/s. Kluczowe znaczenie ma wdrożenie nowoczesnych i ekonomicznych rozwiązań badań nieniszczących, które zapewnią ocenę jakości 100% długości spawu. Istotny wkład w rozwój laboratoriów badawczych, w kontekście wiarygodności uzyskiwanych wyników badania

Keywords:
ultradźwiękowe badania nieniszczące, spawy, Phased-Array, UTPA; FMC

Affiliations:
Lewandowski M.J. - IPPT PAN
Rozbicki J. - IPPT PAN
Smach H. - IPPT PAN
Karwat P. - IPPT PAN
Szczurek A. - other affiliation
Sala J. - other affiliation
Bera A. - other affiliation
4.  Klimonda z., Karwat P., Dobruch-Sobczak K., Piotrzkowska-Wróblewska H., Litniewski J., Assessment of breast cancer response to neoadjuvant chemotherapy based on ultrasound backscattering envelope statistics, Medical Physics, ISSN: 0094-2405, DOI: 10.1002/mp.15428, Vol.1, pp.1-8, 2022

Abstract:
Purpose: Neo-adjuvant chemotherapy (NAC) is used in breast cancer before tumor surgery to reduce the size of the tumor and the risk of spreading. Monitoring the effects of NAC is important because in a number of cases the response to therapy is poor and requires a change in treatment. A new method that uses quantitative ultrasound to assess tumor response to NAC has been presented. The aim was to detect NAC unresponsive tumors at an early stage of treatment. Methods: The method assumes that ultrasound scattering is different for responsive and nonresponsive tumors. The assessment of the NAC effects was based on the differences between the histograms of the ultrasound echo amplitude recorded from the tumor after each NAC dose and from the tissue phantom, estimated using the Kolmogorov–Smirnov statistics (KSS) and the symmetrical Kullback–Leibler divergence (KLD). After therapy, tumors were resected and histopathologically evaluated. The percentage of residual malignant cells was determined and was the basis for assessing the tumor response. The data set included ultrasound data obtained from 37 tumors. The performance of the methods was assessed by means of the area under the receiver operating characteristic curve (AUC). Results: For responding tumors, a decrease in the mean KLD and KSS values was observed after subsequent doses of NAC. In nonresponding tumors, the KLD was higher and did not change in subsequent NAC courses. Classification based on the KSS or KLD parameters allowed to detect tumors not respond- ing to NAC after the first dose of the drug, with AUC equal 0.83±0.06 and 0.84±0.07, respectively. After the third dose, the AUC increased to 0.90±0.05 and 0.91±0.04, respectively. Conclusions: The results indicate the potential usefulness of the proposed parameters in assessing the effectiveness of the NAC and early detection of nonresponding cases.

Keywords:
breast cancer, neoadjuvant therapy assessment, quantitative ultrasound

Affiliations:
Klimonda z. - IPPT PAN
Karwat P. - IPPT PAN
Dobruch-Sobczak K. - IPPT PAN
Piotrzkowska-Wróblewska H. - IPPT PAN
Litniewski J. - IPPT PAN
5.  Lewandowski M., Rozbicki J., Smach H., Karwat P., Szczurek A., Sala J., Bera A., Modelowe rozwiązania skanerów UTPA do badań spawów dla wież wiatrowych, sekcji płaskich oraz konstrukcji wielkogabarytowych on-shore/off-shore, BADANIA NIENISZCZĄCE I DIAGNOSTYKA, ISSN: 2451-4462, DOI: 10.26357/BNID.2022.010, Vol.1-4, pp.89-92, 2022

Abstract:
W ramach realizowanego projektu wdrożeniowego (akronim: BalTECH, finansowanie NCBR POIR) opracowano modelowe stanowiska skanerow UTPA do badań nieniszczących spawow dla asortymentu produktow wytwarzanych w Baltic Operator sp. z o.o. Skanery zapewniają prowadzenie i sprzężenie dwoch głowic Phased-Array (badanie dwustronne). Do realizacji badań UTPA wykorzystano komercyjny aparat Olympus-OmniScan ™ X3, natomiast dlametody UTPA-FMC (Full-Matrix Capture) badawczą platformę ultradźwiękową us4R-lite™ firmy us4us sp. z o.o. Wykonano zestaw ok. 170 probek testowych spawow z rożnymi niezgodnościami dla płyt w zakresie grubości 12–65 mm, ktore zostały przebadanie metodami VT, MT/PT, UT, RT, UTPA. Opracowana procedura badania i wzorce testowe pozwoliły na pełną walidację klasycznej metody UTPA do badania sekcji wież wiatrowych. Eksperymentalne zastosowanie i porownanie metody UTPA-FMC pokazało jej duży potencjał oraz nowe możliwości wizualizacji i oceny wad, w stosunku do klasycznej metody UTPA. Zweryfikowano także możliwość zbierania surowych danych FMC z prędkością do 100 mm/s. Kluczowe znaczenie ma wdrożenie nowoczesnych i ekonomicznych rozwiązań badań nieniszczących, ktore zapewnią ocenę jakości 100% długości spawu. Istotny wkład w rozwoj laboratoriow badawczych, w kontekście wiarygodności uzyskiwanych wynikow badania.

Keywords:
ultradźwiękowe badania nieniszczące, spawy, Phased-Array, UTPA, FMC

Affiliations:
Lewandowski M. - IPPT PAN
Rozbicki J. - IPPT PAN
Smach H. - IPPT PAN
Karwat P. - IPPT PAN
Szczurek A. - other affiliation
Sala J. - other affiliation
Bera A. - other affiliation
6.  Dobruch-Sobczak K.S., Piotrzkowska-Wróblewska H., Karwat P., Klimonda Z., Markiewicz-Grodzicka E., Litniewski J., Quantitative assessment of the echogenicity of a breast tumor predicts the response to neoadjuvant chemotherapy, Cancers, ISSN: 2072-6694, DOI: 10.3390/cancers13143546, Vol.13, No.14, pp.3546-1-22, 2021

Abstract:
The aim of the study was to improve monitoring the treatment response in breast cancer patients undergoing neoadjuvant chemotherapy (NAC). The IRB approved this prospective study. Ultrasound examinations were performed prior to treatment and 7 days after four consecutive NAC cycles. Residual malignant cell (RMC) measurement at surgery was the standard of reference. Alteration in B-mode ultrasound (tumor echogenicity and volume) and the Kullback-Leibler divergence (kld), as a quantitative measure of amplitude difference, were used. Correlations of these parameters with RMC were assessed and Receiver Operating Characteristic curve (ROC) analysis was performed. Thirty-nine patients (mean age 57 y.) with 50 tumors were included. There was a significant correlation between RMC and changes in quantitative parameters (KLD) after the second, third and fourth course of NAC, and alteration in echogenicity after the third and fourth course. Multivariate analysis of the echogenicity and KLD after the third NAC course revealed a sensitivity of 91%, specificity of 92%, PPV = 77%, NPV = 97%, accuracy = 91%, and AUC of 0.92 for non-responding tumors (RMC ≥ 70%). In conclusion, monitoring the echogenicity and KLD parameters made it possible to accurately predict the treatment response from the second course of NAC.

Keywords:
quantitative ultrasound, B-mode ultrasound, echogenicity, breast cancer, neoadjuvant chemotherapy

Affiliations:
Dobruch-Sobczak K.S. - IPPT PAN
Piotrzkowska-Wróblewska H. - IPPT PAN
Karwat P. - IPPT PAN
Klimonda Z. - IPPT PAN
Markiewicz-Grodzicka E. - Oncology Institute (PL)
Litniewski J. - IPPT PAN
7.  Karwat P., Klimonda Z., Styczyński G., Szmigielski C., Litniewski J., Aortic root movement correlation with the function of the left ventricle, Scientific Reports, ISSN: 2045-2322, DOI: 10.1038/s41598-021-83278-x, Vol.11, pp.4473-1-8, 2021

Abstract:
Echocardiographic assessment of systolic and diastolic function of the heart is often limited by image quality. However, the aortic root is well visualized in most patients. We hypothesize that the aortic root motion may correlate with the systolic and diastolic function of the left ventricle of the heart. Data obtained from 101 healthy volunteers (mean age 46.6 ± 12.4) was used in the study. The data contained sequences of standard two-dimensional (2D) echocardiographic B-mode (brightness mode, classical ultrasound grayscale presentation) images corresponding to single cardiac cycles. They also included sets of standard echocardiographic Doppler parameters of the left ventricular systolic and diastolic function. For each B-mode image sequence, the aortic root was tracked with use of a correlation tracking algorithm and systolic and diastolic values of traveled distances and velocities were determined. The aortic root motion parameters were correlated with the standard Doppler parameters used for the assessment of LV function. The aortic root diastolic distance (ARDD) mean value was 1.66 ± 0.26 cm and showed significant, moderate correlation (r up to 0.59, p < 0.0001) with selected left ventricular diastolic Doppler parameters. The aortic root maximal diastolic velocity (ARDV) was 10.8 ± 2.4 cm/s and also correlated (r up to 0.51, p < 0.0001) with some left ventricular diastolic Doppler parameters. The aortic root systolic distance (ARSD) was 1.63 ± 0.19 cm and showed no significant moderate correlation (all r values < 0.40). The aortic root maximal systolic velocity (ARSV) was 9.2 ± 1.6 cm/s and correlated in moderate range only with peak systolic velocity of medial mitral annulus (r = 0.44, p < 0.0001). Based on these results, we conclude, that in healthy subjects, aortic root motion parameters correlate significantly with established measurements of left ventricular function. Aortic root motion parameters can be especially useful in patients with low ultrasound image quality precluding usage of typical LV function parameters.

Affiliations:
Karwat P. - IPPT PAN
Klimonda Z. - IPPT PAN
Styczyński G. - Medical University of Warsaw (PL)
Szmigielski C. - Medical University of Warsaw (PL)
Litniewski J. - IPPT PAN
8.  Dobruch-Sobczak K., Piotrzkowska-Wróblewska H., Klimonda Z., Karwat P., Roszkowska-Purska K., Clauser P., Baltzer P.A.T., Litniewski J., Multiparametric ultrasound examination for response assessment in breast cancer patients undergoing neoadjuvant therapy, Scientific Reports, ISSN: 2045-2322, DOI: 10.1038/s41598-021-82141-3, Vol.11, pp.2501 -1-9, 2021

Abstract:
To investigate the performance of multiparametric ultrasound for the evaluation of treatment response in breast cancer patients undergoing neoadjuvant chemotherapy (NAC). The IRB approved this prospective study. Breast cancer patients who were scheduled to undergo NAC were invited to participate in this study. Changes in tumour echogenicity, stiffness, maximum diameter, vascularity and integrated backscatter coefficient (IBC) were assessed prior to treatment and 7 days after four consecutive NAC cycles. Residual malignant cell (RMC) measurement at surgery was considered as standard of reference. RMC < 30% was considered a good response and > 70% a poor response. The correlation coefficients of these parameters were compared with RMC from post-operative histology. Linear Discriminant Analysis (LDA), cross-validation and Receiver Operating Characteristic curve (ROC) analysis were performed. Thirty patients (mean age 56.4 year) with 42 lesions were included. There was a significant correlation between RMC and echogenicity and tumour diameter after the 3rd course of NAC and average stiffness after the 2nd course. The correlation coefficient for IBC and echogenicity calculated after the first four doses of NAC were 0.27, 0.35, 0.41 and 0.30, respectively. Multivariate analysis of the echogenicity and stiffness after the third NAC revealed a sensitivity of 82%, specificity of 90%, PPV = 75%, NPV = 93%, accuracy = 88% and AUC of 0.88 for non-responding tumours (RMC > 70%). High tumour stiffness and persistent hypoechogenicity after the third NAC course allowed to accurately predict a group of non-responding tumours. A correlation between echogenicity and IBC was demonstrated as well.

Affiliations:
Dobruch-Sobczak K. - IPPT PAN
Piotrzkowska-Wróblewska H. - IPPT PAN
Klimonda Z. - IPPT PAN
Karwat P. - IPPT PAN
Roszkowska-Purska K. - other affiliation
Clauser P. - other affiliation
Baltzer P.A.T. - other affiliation
Litniewski J. - IPPT PAN
9.  Klimonda Z., Karwat P., Dobruch-Sobczak K., Piotrzkowska-Wróblewska H., Litniewski J., Breast-lesions characterization using quantitative ultrasound features of peritumoral tissue, Scientific Reports, ISSN: 2045-2322, DOI: 10.1038/s41598-019-44376-z, Vol.9, pp.7963-1-9, 2019

Abstract:
The presented studies evaluate for the first time the efficiency of tumour classification based on the quantitative analysis of ultrasound data originating from the tissue surrounding the tumour. 116 patients took part in the study after qualifying for biopsy due to suspicious breast changes. The RF signals collected from the tumour and tumour-surroundings were processed to determine quantitative measures consisting of Nakagami distribution shape parameter, entropy, and texture parameters. The utility of parameters for the classification of benign and malignant lesions was assessed in relation to the results of histopathology. The best multi-parametric classifier reached an AUC of 0.92 and of 0.83 for outer and intra-tumour data, respectively. A classifier composed of two types of parameters, parameters based on signals scattered in the tumour and in the surrounding tissue, allowed the classification of breast changes with sensitivity of 93%, specificity of 88%, and AUC of 0.94. Among the 4095 multi-parameter classifiers tested, only in eight cases the result of classification based on data from the surrounding tumour tissue was worse than when using tumour data. The presented results indicate the high usefulness of QUS analysis of echoes from the tissue surrounding the tumour in the classification of breast lesions.

Affiliations:
Klimonda Z. - IPPT PAN
Karwat P. - IPPT PAN
Dobruch-Sobczak K. - IPPT PAN
Piotrzkowska-Wróblewska H. - IPPT PAN
Litniewski J. - IPPT PAN
10.  Piotrzkowska-Wróblewska H., Dobruch-Sobczak K., Klimonda Z., Karwat P., Roszkowska-Purska K., Gumowska M., Litniewski J., Monitoring breast cancer response to neoadjuvant chemotherapy with ultrasound signal statistics and integrated backscatter, PLOS ONE, ISSN: 1932-6203, DOI: 10.1371/journal.pone.0213749, Vol.14, No.3, pp.e0213749-1-15, 2019

Abstract:
Background: Neoadjuvant chemotherapy (NAC) is used in patients with breast cancer to reduce tumor focus, metastatic risk, and patient mortality. Monitoring NAC effects is necessary to capture resistant patients and stop or change treatment. The existing methods for evaluating NAC results have some limitations. The aim of this study was to assess the tumor response at an early stage, after the first doses of the NAC, based on the variability of the backscattered ultrasound energy, and backscatter statistics. The backscatter statistics has not previously been used to monitor NAC effects. Methods: The B-mode ultrasound images and raw radio frequency data from breast tumors were obtained using an ultrasound scanner before chemotherapy and 1 week after each NAC cycle. The study included twenty-four malignant breast cancers diagnosed in sixteen patients and qualified for neoadjuvant treatment before surgery. The shape parameter of the homodyned K distribution and integrated backscatter, along with the tumor size in the longest dimension, were determined based on ultrasound data and used as markers for NAC response. Cancer tumors were assigned to responding and non-responding groups, according to histopathological evaluation, which was a reference in assessing the utility of markers. Statistical analysis was performed to rate the ability of markers to predict the final NAC response based on data obtained after subsequent therapeutic doses. Results: Statistically significant differences (p<0.05) between groups were obtained after 2, 3, 4, and 5 doses of NAC for quantitative ultrasound markers and after 5 doses for the assessment based on maximum tumor dimension. Statistical analysis showed that, after the second and third NAC courses the classification based on integrated backscatter marker was characterized by an AUC of 0.69 and 0.82, respectively. The introduction of the second quantitative marker describing the statistical properties of scattering increased the corresponding AUC values to 0.82 and 0.91. Conclusions: Quantitative ultrasound information can characterize the tumor's pathological response better and at an earlier stage of therapy than the assessment of the reduction of its dimensions. The introduction of statistical parameters of ultrasonic backscatter to monitor the effects of chemotherapy can increase the effectiveness of monitoring and contribute to a better personalization of NAC therapy.

Affiliations:
Piotrzkowska-Wróblewska H. - IPPT PAN
Dobruch-Sobczak K. - IPPT PAN
Klimonda Z. - IPPT PAN
Karwat P. - IPPT PAN
Roszkowska-Purska K. - other affiliation
Gumowska M. - other affiliation
Litniewski J. - IPPT PAN
11.  Dobruch-Sobczak K., Piotrzkowska-Wróblewska H., Klimonda Z., Secomski W., Karwat P., Markiewicz-Grodzicka E., Kolasińska-Ćwikła A., Roszkowska-Purska K., Litniewski J., Monitoring the response to neoadjuvant chemotherapy in patients with breast cancer using ultrasound scattering coefficient: a preliminary report, Journal of Ultrasonography, ISSN: 2084-8404, DOI: 10.15557/JoU.2019.0013, Vol.19, No.77, pp.89-97, 2019

Abstract:
Objective: Neoadjuvant chemotherapy was initially used in locally advanced breast cancer, and currently it is recommended for patients with Stage 3 and with early-stage disease with human epidermal growth factor receptors positive or triple-negative breast cancer. Ultrasound imaging in combination with a quantitative ultrasound method is a novel diagnostic approach. Aim of study: The aim of this study was to analyze the variability of the integrated backscatter coefficient, and to evaluate their use to predict the effectiveness of treatment and compare to ultrasound examination results. Material and method: Ten patients (mean age 52.9) with 13 breast tumors (mean dimension 41 mm) were selected for neoadjuvant chemotherapy. Ultrasound was performed before the treatment and one week after each course of neoadjuvant chemotherapy. The dimensions were assessed adopting the RECIST criteria. Tissue responses were classified as pathological response into the following categories: not responded to the treatment (G1, cell reduction by ≤9%) and responded to the treatment partially: G2, G3, G4, cell reduction by 10–29% (G2), 30–90% (G3), >90% (G4), respectively, and completely. Results: In B-mode examination partial response was observed in 9/13 cases (completely, G1, G3, G4), and stable disease was demonstrated in 3/13 cases (completely, G1, G4). Complete response was found in 1/13 cases. As for backscatter coefficient, 10/13 tumors (completely, and G2, G3, and G4) were characterized by an increased mean value of 153%. Three tumors 3/13 (G1) displayed a decreased mean value of 31%. Conclusion: The variability of backscatter coefficient, could be associated with alterations in the structure of the tumor tissue during neoadjuvant chemotherapy. There were unequivocal differences between responded and non-responded patients. The backscatter coefficient analysis correlated better with the results of histopathological verification than with the B-mode RECIST criteria.

Keywords:
integrated backscatter coefficient (IBSCs), neoadjuvant chemotherapy (NAC), breast cancer, ultrasound

Affiliations:
Dobruch-Sobczak K. - IPPT PAN
Piotrzkowska-Wróblewska H. - IPPT PAN
Klimonda Z. - IPPT PAN
Secomski W. - IPPT PAN
Karwat P. - IPPT PAN
Markiewicz-Grodzicka E. - Oncology Institute (PL)
Kolasińska-Ćwikła A. - Institute of Oncology (PL)
Roszkowska-Purska K. - other affiliation
Litniewski J. - IPPT PAN
12.  Karwat P., Kujawska T., Lewin P.A., Secomski W., Gambin B., Litniewski J., Determining temperature distribution in tissue in the focal plane of the high (>100 W/cm2) intensity focused ultrasound beam using phase shift of ultrasound echoes, Ultrasonics, ISSN: 0041-624X, DOI: 10.1016/j.ultras.2015.10.002, Vol.65, pp.211-219, 2016

Abstract:
In therapeutic applications of High Intensity Focused Ultrasound (HIFU) the guidance of the HIFU beam and especially its focal plane is of crucial importance. This guidance is needed to appropriately target the focal plane and hence the whole focal volume inside the tumor tissue prior to thermo-ablative treatment and beginning of tissue necrosis. This is currently done using Magnetic Resonance Imaging that is relatively expensive. In this study an ultrasound method, which calculates the variations of speed of sound in the locally heated tissue volume by analyzing the phase shifts of echo-signals received by an ultrasound scanner from this very volume is presented. To improve spatial resolution of B-mode imaging and minimize the uncertainty of temperature estimation the acoustic signals were transmitted and received by 8 MHz linear phased array employing Synthetic Transmit Aperture (STA) technique. Initially, the validity of the algorithm developed was verified experimentally in a tissue-mimicking phantom heated from 20.6 to 48.6°C. Subsequently, the method was tested using a pork loin sample heated locally by a 2 MHz pulsed HIFU beam with focal intensity ISATA of 129 W/cm2. The temperature calibration of 2D maps of changes in the sound velocity induced by heating was performed by comparison of the algorithm-determined changes in the sound velocity with the temperatures measured by thermocouples located in the heated tissue volume. The method developed enabled ultrasound temperature imaging of the heated tissue volume from the very inception of heating with the contrast-to-noise ratio of 3.5–12 dB in the temperature range 21–56°C. Concurrently performed, conventional B-mode imaging revealed CNR close to zero dB until the temperature reached 50°C causing necrosis. The data presented suggest that the proposed method could offer an alternative to MRI-guided temperature imaging for prediction of the location and extent of the thermal lesion prior to applying the final HIFU treatment.

Keywords:
Ultrasonic temperature imaging, HIFU, Echo phase shift, Velocity image contrast

Affiliations:
Karwat P. - IPPT PAN
Kujawska T. - IPPT PAN
Lewin P.A. - Drexel University (US)
Secomski W. - IPPT PAN
Gambin B. - IPPT PAN
Litniewski J. - IPPT PAN
13.  Lewandowski M., Walczak M., Karwat P., Witek B., Karłowicz P., Research and Medical Transcranial Doppler System, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.1515/aoa-2016-0074, Vol.41, No.4, pp.773-781, 2016

Abstract:
A new ultrasound digital transcranial Doppler system (digiTDS) is introduced. The digiTDS enables diagnosis of intracranial vessels which are rather difficult to penetrate for standard systems. The device can display a color map of flow velocities (in time-depth domain) and a spectrogram of a Doppler signal obtained at particular depth. The system offers a multigate processing which allows to display a number of spectrograms simultaneously and to reconstruct a flow velocity profile.
The digital signal processing in digiTDS is partitioned between hardware and software parts. The hardware part (based on FPGA) executes a signal demodulation and reduces data stream. The software part (PC) performs the Doppler processing and display tasks. The hardware-software partitioning allowed to build a flexible Doppler platform at a relatively low cost.
The digiTDS design fulfills all necessary medical standards being a new useful tool in the transcranial field as well as in heart velocimetry research.

Keywords:
Doppler system, digital signal processing, hardware-software partitioning, field programmable gate arrays

Affiliations:
Lewandowski M. - IPPT PAN
Walczak M. - IPPT PAN
Karwat P. - IPPT PAN
Witek B. - IPPT PAN
Karłowicz P. - Sonomed Sp. z o.o. (PL)
14.  Karwat P., Kujawska T., Secomski W., Gambin B., Litniewski J., Application of ultrasound to noninvasive imaging of temperature distribution induced in tissue, HYDROACOUSTICS, ISSN: 1642-1817, Vol.19, pp.219-228, 2016

Abstract:
Therapeutic and surgical applications of High Intensity Focused Ultrasound (HIFU) require monitoring of local temperature rises induced inside tissues. It is needed to appropriately target the focal plane, and hence the whole focal volume inside the tumor tissue, prior to thermo-ablative treatment, and the beginning of tissue necrosis. In this study we present an ultrasound method, which calculates the variations of the speed of sound in the locally heated tissue. Changes in velocity correspond to temperature change. The method calculates a 2D distribution of changes in the sound velocity, by estimation of the local phase shifts of RF echo-signals backscattered from the heated tissue volume (the focal volume of the HIFU beam), and received by an ultrasound scanner (23). The technique enabled temperature imaging of the heated tissue volume from the very inception of heating. The results indicated that the contrast sensitivity for imaging of relative changes in the sound speed was on the order of 0.06%; corresponding to an increase in the tissue temperature by about 2 °C.

Keywords:
HIFU, echo phase shift, parametric imaging, velocity/brightness CNR

Affiliations:
Karwat P. - IPPT PAN
Kujawska T. - IPPT PAN
Secomski W. - IPPT PAN
Gambin B. - IPPT PAN
Litniewski J. - IPPT PAN
15.  Klimonda Z., Litniewski J., Karwat P., Nowicki A., Spatial and Frequency Compounding in Application to Attenuation Estimation in Tissue, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.2478/aoa-2014-0056, Vol.39, No.4, pp.519-527, 2014

Abstract:
The soft tissue attenuation is an interesting parameter from medical point of view, because the value of attenuation coefficient is often related to the state of the tissue. Thus, the imaging of the attenuation coefficient distribution within the tissue could be a useful tool for ultrasonic medical diagnosis. The method of attenuation estimation based on tracking of the mean frequency changes in a backscattered signal is presented in this paper. The attenuation estimates are characterized by high variance due to stochastic character of the backscattered ultrasonic signal and some special methods must be added to data processing to improve the resulting images. The following paper presents the application of Spatial Compounding (SC), Frequency Compounding (FC) and the combination of both. The resulting parametric images are compared by means of root-mean-square errors. The results show that combined SC and FC techniques significantly improve the quality and accuracy of parametric images of attenuation distribution.

Keywords:
tissue attenuation estimation, parametric imaging, synthetic aperture, spatial compounding, frequency compounding

Affiliations:
Klimonda Z. - IPPT PAN
Litniewski J. - IPPT PAN
Karwat P. - IPPT PAN
Nowicki A. - IPPT PAN
16.  Karwat P., Litniewski J., Kujawska T., Secomski W., Krawczyk K., Noninvasive Imaging of Thermal Fields Induced in Soft Tissues In Vitro by Pulsed Focused Ultrasound Using Analysis of Echoes Displacement, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.2478/aoa-2014-0014, Vol.39, No.1, pp.139-144, 2014

Abstract:
Therapeutic and surgical applications of focused ultrasound require monitoring of local temperature rises induced inside tissues. From an economic and practical point of view ultrasonic imaging techniques seem to be the most suitable for the temperature control. This paper presents an implementation of the ultrasonic echoes displacement estimation technique for monitoring of local temperature rise in tissue during its heating by focused ultrasound The results of the estimation were compared to the temperature measured with thermocouple. The obtained results enable to evaluate the temperature fields induced in tissues by pulsed focused ultrasonic beams using non-invasive imaging ultrasound technique

Keywords:
HIFU, therapeutic ultrasound, ultrasonic imaging, echo strain estimation

Affiliations:
Karwat P. - IPPT PAN
Litniewski J. - IPPT PAN
Kujawska T. - IPPT PAN
Secomski W. - IPPT PAN
Krawczyk K. - IPPT PAN
17.  Gawlikowski M., Lewandowski M., Nowicki A., Kustosz R., Walczak M., Karwat P., Karłowicz P., The Application of Ultrasonic Methods to Flow Measurement and Detection of Microembolus in Heart Prostheses, ACTA PHYSICA POLONICA A, ISSN: 0587-4246, DOI: 10.12693/APhysPolA.124.417, Vol.124, No.3, pp.417-420, 2013

Abstract:
For the last 20 years the world cardiosurgery has presented a considerable change of attitude to mechanical circulatory support. In spite of technological progress the main problems in ventricular assist devices are: thrombosis and low accuracy of flow measurements. In this paper the prototype of multi-gate Doppler flowmeter intended for cardiac assist system ReligaHeart EXT has been presented as well as the possibility of ultrasonic micro embolus detection.

Keywords:
artificial heart, microemboli, ultrasound Doppler

Affiliations:
Gawlikowski M. - other affiliation
Lewandowski M. - IPPT PAN
Nowicki A. - IPPT PAN
Kustosz R. - other affiliation
Walczak M. - IPPT PAN
Karwat P. - IPPT PAN
Karłowicz P. - Sonomed Sp. z o.o. (PL)
18.  Karwat P., Klimonda Z., Seklewski M., Lewandowski M., Nowicki A., Data reduction method for synthetic transmit aperture algorithm, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, Vol.35, No.4, pp.635-642, 2010

Abstract:
Ultrasonic methods of human body internal structures imaging are being continuously enhanced. New algorithms are created to improve certain output parameters. A synthetic aperture method (SA) is an example which allows to display images at higher frame-rate than in case of conventional beam-forming method. Higher computational complexity is a limitation of SA method and it can prevent from obtaining a desired reconstruction time. This problem can be solved by neglecting a part of data. Obviously it implies a decrease of imaging quality, however a proper data reduction technique would minimize the image degradation. A proposed way of data reduction can be used with synthetic transmit aperture method (STA) and it bases on an assumption that a signal obtained from any pair of transducers is the same, no matter which transducer transmits and which receives. According to this postulate, nearly a half of the data can be ignored without image quality decrease. The presented results of simulations and measurements with use of wire and tissue phantom prove that the proposed data reduction technique reduces the amount of data to be processed by half, while maintaining resolution and allowing only a small decrease of SNR and contrast of resulting images.

Keywords:
ultrasonic imaging, synthetic transmit aperture, data reduction, effective aperture, reciprocity

Affiliations:
Karwat P. - IPPT PAN
Klimonda Z. - IPPT PAN
Seklewski M. - other affiliation
Lewandowski M. - IPPT PAN
Nowicki A. - IPPT PAN
19.  Sęklewski M., Karwat P., Klimonda Z., Lewandowski M., Nowicki A., Preliminary results: comparison of different schemes of synthetic aperture technique in ultrasonic imaging, HYDROACOUSTICS, ISSN: 1642-1817, Vol.13, pp.243-252, 2010

Abstract:
The Synthetic Aperture (SA) methods are widespread and successfully used in radar technology, as well as in the sonar systems. The advantages of high framerate and its relatively good resolution in the whole area of scanning, make this technique an object of interest in medical imaging methods such as ultrasonography (US). This paper describes the possible usage of the SA method in ultrasound imaging. The introduction to the principles of the SA technique in ultrasonography is presented. The measurements of different SA schemes were conducted using the set-up consisting of the research ultrasonograph module, the PC and the special wire phantom. The results for different schemes of image reconstruction are presented. Particularly the Synthetic Transmit Aperture (STA) technique was concerned. Results of the STA method are discussed in this paper.

Keywords:
synthetic aperture focusing technique, ultrasonic imaging

Affiliations:
Sęklewski M. - IPPT PAN
Karwat P. - IPPT PAN
Klimonda Z. - IPPT PAN
Lewandowski M. - IPPT PAN
Nowicki A. - IPPT PAN
20.  Karwat P., Nowicki A., Lewandowski M., Blood scattering model for pulsed doppler, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, Vol.34, No.4, pp.677-685, 2009

Abstract:
The subject of this paper is a new software simulating ultrasound signal scattered on moving blood cells during Doppler examination of blood flow velocity using pulsed technique. Generated data are used for optimization and validation of Doppler signals processing algorithms.
The algorithm is based on the finite elements method FEM. A rigorous set of postulates which simplifies physics of modeled phenomenon enables to quicken the program significantly while preserving important properties (from application point of view) of generated signal.
The paper includes description of Doppler RF signal generation algorithm. The simplifying postulates are listed together with resulting signal fidelity degradation. Finally generated raw data is presented together with its Doppler Audio and Color processed version.
The signal processing results enable to reconstruct correctly the velocity profile and its time dependence. The results clearly confirm that the data generated by the algorithm are suitable for Doppler signals processing.

Keywords:
RF signal simulation, scattering on blood cells, pulsed Doppler

Affiliations:
Karwat P. - IPPT PAN
Nowicki A. - IPPT PAN
Lewandowski M. - IPPT PAN

List of chapters in recent monographs
1. 
Litniewski J., Klimonda Z., Karwat P., Piotrzkowska-Wróblewska H., Dobruch-Sobczak K., Tymkiewicz R., Gambin B., Postępy Akustyki 2016, rozdział: Cancer malignancy sonic markers, Polskie Towarzystwo Akustyczne, Oddział Warszawski, Warszawa, Poland, pp.49-60, 2016
2. 
Karwat P., Postępy Akustyki 2016, rozdział: Wydajna obliczeniowo metoda rekonstrukcji pola prędkości dźwięku w tkankach miękkich, Polskie Towarzystwo Akustyczne, Oddział Warszawski, Warszawa, Poland, Instytut Podstawowych Problemów Techniki PAN, pp.27-38, 2016
3. 
Lewandowski M., Walczak M., Karwat P., Nowicki A., Karłowicz P., Polskie protezy serca, opracowanie konstrukcji, badania kwalifikacyjne, przedkliniczne i kliniczne., rozdział: Wykonanie modelu i implementacja oprogramowania do ultradźwiękowego pomiaru przepływu krwi, FRK, Zabrze. Praca zbiorowa pod redakcją: Kustosz R., Gonsior M., Jarosz A., pp.3-21, 2013

Conference papers
1.  Klimonda Z., Karwat P., Dobruch-Sobczak K., Piotrzkowska-Wróblewska H., Litniewski J., On the assessment of local tumor response to neoadjuvant chemotherapy, IEEE IUS 2023, International Ultrasonics Symposium (IUS) , 2023-09-03/09-08, Monteral (CA), pp.1-4, 2023
2.  Byra M., Karwat P., Ryzhankow I., Komorowski P., Klimonda Z., Fura Ł., Pawłowska A., Żołek N., Litniewski J., Deep meta-learning for the selection of accurate ultrasound based breast mass classifier, IUS 2022, IEEE, International Ultrasonic Symposium, 2022-10-10/10-13, Wenecja (IT), DOI: 10.1109/IUS54386.2022.9957191, pp.1-4, 2022

Abstract:
Standard classification methods based on hand-crafted morphological and texture features have achieved good performance in breast mass differentiation in ultrasound (US).
In comparison to deep neural networks, commonly perceived as ‘black-box’ models, classical techniques are based on features that have well-understood medical and physical interpretation. However, classifiers based on morphological features commonly
underperform in the presence of the shadowing artifact and ill-defined mass borders, while texture based classifiers may fail when the US image is too noisy. Therefore, in practice it would be beneficial to select the classification method based on the appearance of the particular US image. In this work, we develop a deep meta-network that can automatically process input breast mass US images and recommend whether to apply the shape or
texture based classifier for the breast mass differentiation. Our preliminary results demonstrate that meta-learning techniques can be used to improve the performance of the standard classifiers based on handcrafted features. With the proposed meta-learning based approach, we achieved the area under the receiver operating characteristic curve of 0.95 and accuracy of 0.91.

Keywords:
breast mass classification, deep learning, meta-learning, morphological features, texture features

Affiliations:
Byra M. - IPPT PAN
Karwat P. - IPPT PAN
Ryzhankow I. - IPPT PAN
Komorowski P. - other affiliation
Klimonda Z. - IPPT PAN
Fura Ł. - IPPT PAN
Pawłowska A. - IPPT PAN
Żołek N. - IPPT PAN
Litniewski J. - IPPT PAN
3.  Karwat P., Klimonda Z., Piotrzkowska-Wróblewska H., Dobruch-Sobczak K., Litniewski J., Quantitative ultrasound examination of peritumoral tissue improves classification of breast lesions, IUS 2019, IEEE, International Ultrasonics Symposium, 2019-10-06/10-09, Glasgow (GB), pp.1509-1511, 2019
4.  Klimonda Z., Karwat P., Piotrzkowska-Wróblewska H., Dobruch-Sobczak K., Litniewski J., Ultrasound scattering statistics predicts the result of neoadjuvant chemotherapy of breast tumors at an early stage of treatment, IUS 2019, IEEE, International Ultrasonics Symposium, 2019-10-06/10-09, Glasgow (GB), pp.1512-1514, 2019
5.  Karwat P., Computationally efficient algorithm for sound speed imaging in pulse-echo ultrasound, 2019 ICU Bruges, 2019 International Congress on Ultrasonics, 2019-09-03/09-06, Bruges (BE), DOI: 10.1121/2.0001109, Vol.38, No.1, pp.020005-1-6, 2019

Abstract:
Precise information about the spatial distribution of sound speed in tissue has diagnostic value in itself, and also enables effective aberration correction in standard ultrasonic imaging. An algorithm called Computed Ultrasound Tomography in Echo mode (CUTE) makes it possible to reconstruct quantitative sound speed images. However, the computational cost is high, which is an obstacle to CUTE implementation in real-time imaging systems. This paper presents an improved version of the CUTE algorithm called Quick-CUTE (Q-CUTE). The CUTE algorithm uses the inverse transformation matrix to reconstruct the sound speed spatial distribution. The Q-CUTE algorithm is based on simplified model with unified integration paths which enables solving the inverse problem without use of a large transformation matrix. The Q-CUTE algorithm was verified through numerical simulations. The obtained results differ from those of the CUTE algorithm but maintain the quantitative character of sound speed imaging. The computational complexity of the Q-CUTE algorithm is proportional to N while in case of the CUTE it is proportional to N squared (where N is a number of pixels in the sound speed image). This means that the Q-CUTE algorithm allows the quantitative sound speed imaging to operate in real time.

Affiliations:
Karwat P. - IPPT PAN
6.  Klimonda Z., Karwat P., Dobruch-Sobczak K., Piotrzkowska-Wróblewska H., Litniewski J., Assessment of a breast cancer response to neoadjuvant chemotherapy using backscatter ultrasound statistics, 2019 ICU Bruges, 2019 International Congress on Ultrasonics, 2019-09-03/09-06, Bruges (BE), DOI: 10.1121/2.0001104, Vol.38, No.1, pp.020003-1-5, 2019
7.  Piotrzkowska-Wróblewska H., Klimonda Z., Dobruch-Sobczak K., Karwat P., Secomski W., Litniewski J., Quantitative Ultrasound for Chemotherapy Monitoring, IEEE 2018, IEEE Joint Conference - Acoustics, 2018-09-11/09-14, Ustka (PL), DOI: 10.1109/ACOUSTICS.2018.8502336, pp.268-271, 2018

Abstract:
Neoadjuvant chemotherapy (NAC) is used in breast cancer patients to reduce tumor size, decrease the risk of local recurrence, and diminish the likelihood of metastases, all of which reduce patient mortality. Assessment of the response to NAC at an early stage of treatment allows therapy to be personalized. The quantitative ultrasound method is a novel diagnostic approach with great potential to improve outcomes for breast cancer patients. The aim of this study was to analyze the variability of the integrated backscatter coefficient (IBSC) in the context of the assessment of changes in tumor tissue structure resulting from chemotherapy, and to evaluate use of IBSC to predict the effectiveness of treatment. Ultrasound data (B-mode images and raw ultrasonic radio frequency signals RF) were collected from cancerous tumors from patients intended to NAC before starting treatment and a week after each chemotherapy dose. Data were processed to generate IBSC maps and to determine IBSC mean values. The assessment of tumors using IBSC, in comparison with histopathological verification, showed that IBSC changes can be associated with changes which tumor structure changes during NAC. IBSC analysis correlated better with the results of histopathological verification than B-mode imaging.

Affiliations:
Piotrzkowska-Wróblewska H. - IPPT PAN
Klimonda Z. - IPPT PAN
Dobruch-Sobczak K. - IPPT PAN
Karwat P. - IPPT PAN
Secomski W. - IPPT PAN
Litniewski J. - IPPT PAN
8.  Klimonda Z., Dobruch-Sobczak K., Piotrzkowska-Wróblewska H., Karwat P., Litniewski J., Quantitative Ultrasound of Tumor Surrounding Tissue for Enhancement of Breast Cancer Diagnosis, IWBBIO 2018, 6th International Work-Conference, 2018-04-25/04-27, Granada (ES), DOI: 10.1007/978-3-319-78759-6_18, Vol.10814, pp.186-197, 2018

Abstract:
Breast cancer is one of the leading causes of cancer-related death in female patients. The quantitative ultrasound techniques being developed recently provide useful information facilitating the classification of tumors as malignant or benign. Quantitative parameters are typically determined on the basis of signals scattered within the tumor. The present paper demonstrates the utility of quantitative data estimated based on signal backscatter in the tissue surrounding the tumor. Two quantitative parameters, weighted entropy and Nakagami shape parameter were calculated from the backscatter signal envelope. The ROC curves and the AUC parameter values were used to assess their ability to classify neoplastic lesions. Results indicate that data from tissue surrounding the tumor may characterize it better than data from within the tumor. AUC values were on average 18% higher for parameters calculated from data collected from the tissue surrounding the lesion than from the data from the lesion itself.

Keywords:
uantitative ultrasound, Tissue characterisation, Tumor classification

Affiliations:
Klimonda Z. - IPPT PAN
Dobruch-Sobczak K. - IPPT PAN
Piotrzkowska-Wróblewska H. - IPPT PAN
Karwat P. - IPPT PAN
Litniewski J. - IPPT PAN
9.  Steifer T., Lewandowski M., Karwat P., Gawlikowski M., Automatic emboli detection system for the artificial heart, Physics Procedia, ISSN: 1875-3892, DOI: 10.1016/j.phpro.2015.08.254, Vol.70, pp.1181-1184, 2015

Abstract:
In spite of the progress in material engineering and ventricular assist devices construction, thromboembolism remains the most crucial problem in mechanical heart supporting systems. Therefore, the ability to monitor the patient’s blood for clot formation should be considered an important factor in development of heart supporting systems. The well-known methods for automatic embolus detection are based on the monitoring of the ultrasound Doppler signal. A working system utilizing ultrasound Doppler is being developed for the purpose of flow estimation and emboli detection in the clinical artificial heart ReligaHeart EXT. The system will be based on the existing dual channel multi-gate Doppler device with RF digital processing. A specially developed clamp-on cannula probe, equipped with 2 − 4MHz piezoceramic transducers, enables easy system setup. We present the issues related to the development of automatic emboli detection via Doppler measurements. We consider several algorithms for the flow estimation and emboli detection. We discuss their efficiency and confront them with the requirements of our experimental setup. Theoretical considerations are then met with preliminary experimental findings from a) flow studies with blood mimicking fluid and b) in-vitro flow studies with animal blood. Finally, we discuss some more methodological issues - we consider several possible approaches to the problem of verification of the accuracy of the detection system.

Keywords:
microemboli, embolism, Doppler ultrasound, ventricular assist device

Affiliations:
Steifer T. - IPPT PAN
Lewandowski M. - IPPT PAN
Karwat P. - IPPT PAN
Gawlikowski M. - other affiliation
10.  Lewandowski M., Karwat P., Kudelka J., Kleczek T., GPU Implementation of the STA Algorithm on I/Q Data, IUS 2012, IEEE International Ultrasonics Symposium, 2012-10-07/10-10, Dresden (DE), DOI: 10.1109/ULTSYM.2012.0564, pp.2258-2261, 2012

Abstract:
GPU computing is a new paradigm in high performance signal and image processing. Massive parallel processing offered by the GPUs provides high acceleration of computations when they are properly implemented. Ultrasound image reconstruction is one of these highly parallel classes of algorithms. Massive amount of multichannel input data and deterministic order of execution makes US applications good candidates for high performance GPU implementation. Our goal is to design a versatile ultrasound platform with GPU real-time processing. The project is based on a new system architecture allowing for bandwidth and scalability of processing power. We implemented and optimized SAFT image reconstruction algorithms on CUDA. The study shows that a single GTX-580 GPU card is capable of reconstructing the 128-channel I/Q data into 256×256 High Resolution Images (HRI) at a frame-rate of 44.64 fps which is an equivalent of 5700 Low Resolution Images (LRI) per second.

Keywords:
ultrasonic imaging, synthetic aperture, GPU, CUDA

Affiliations:
Lewandowski M. - IPPT PAN
Karwat P. - IPPT PAN
Kudelka J. - other affiliation
Kleczek T. - other affiliation
11.  Karwat P., Klimonda Z., Lewandowski M., Nowicki A., Imaging Quality of the Classical Beamforming, SAFT and Plane Wave Imaging – Experimental Results, IUS 2012, IEEE International Ultrasonics Symposium, 2012-10-07/10-10, Dresden (DE), DOI: 10.1109/ULTSYM.2012.0320, pp.1283-1286, 2012

Abstract:
The synthetic aperture focusing techniques (SAFT) are well known and widely deployed in radar techniques. Increasing processing power of modern computers allows effective implementation of various SAFT schemes in medical ultrasound systems with multi-element probes. The advance of the SAFT over the classical beamforming (BFR) is dynamic focusing in receive and transmit as well, which brings high resolution on every imaging point. We intend to develop the ultrasound imaging platform with some of the SAFT schemes implemented. The choice of the scheme must be preceded by examination of the imaging quality parameters. The results of the comparison of different SAFT schemes with conventional beamforming are presented in the paper. The results indicate that SAFT schemes can work better than BFR scheme. For example, for some point located near the center of the image the full width at half maximum (FWHM) was equal approximately 0.5, 0.4 and 0.3 mm, while the contrast-to-noise ratio (CNR) was equal 18, 19, and 19 dB for BFR, STA and PWI respectively.

Keywords:
Ultrasonic imaging, SAFT, Plane Wave Imaging

Affiliations:
Karwat P. - IPPT PAN
Klimonda Z. - IPPT PAN
Lewandowski M. - IPPT PAN
Nowicki A. - IPPT PAN
12.  Klimonda Z., Litniewski J., Karwat P., Secomski W., Nowicki A., Tissue attenuation imaging - Synthetic Aperture Focusing versus Spatial Compounding, IUS 2012, IEEE International Ultrasonics Symposium, 2012-10-07/10-10, Dresden (DE), DOI: 10.1109/ULTSYM.2012.0590, pp.2361-2363, 2012

Abstract:
The long term goal of this research is to develop the system enabling the imaging and quantitative measure of ultrasonic attenuation in tissue. It may support the diagnosis by accurate discrimination of the lesions from normal tissue at the early stage of the disease. The attenuation is estimated from the stochastic ultrasonic backscatter and time/spatial averaging is necessary to achieve reasonable accuracy. However the averaging worsens the spatial resolution. Two techniques of ultrasonic imaging, the Synthetic Aperture Focusing technique (SAFT) and Spatial Compounding (SC), were applied and compared with respect to the quality of attenuation estimation. The ultrasonic RF data were collected from a tissue mimicking phantom using ultrasonic scanner (Ultrasonix SonixTOUCH). Both acquired echoes-sets were processed in the same way in order to calculate the downshift in a mean frequency fm of the backscatter signal and resulting spatial distribution of attenuation coefficient. Compensation for the diffraction effects was included in the data processing. The RF data obtained with use of the SAFT proved to be more suitable for attenuation estimation.

Keywords:
tissue attenuation imaging, synthetic aperture, spatial compounding

Affiliations:
Klimonda Z. - IPPT PAN
Litniewski J. - IPPT PAN
Karwat P. - IPPT PAN
Secomski W. - IPPT PAN
Nowicki A. - IPPT PAN
13.  Karwat P., Litniewski J., Secomski W., Kujawska T., Krawczyk K., Kruglenko E., Gambin B., Nowicki A., Nieinwazyjne obrazowanie temperatury tkanki miękkiej in vitro metodą analizy przemieszczenia ech ultradźwiękowych, 59th Open Seminar on Acoustics, 2012-09-10/09-14, Boszkowo (PL), pp.101-104, 2012

Abstract:
Terapeutyczne i chirurgiczne zastosowania ogniskowych ultradźwięków wymagają monitorowania lokalnych zmian temperatury w tkance. Najkorzystniejsze z punktu widzenia użytkowego i ekonomicznego byłoby zastosowanie do tych celów technik ultradźwiękowych.
Praca przedstawia próbę zastosowania metody estymacji przemieszczenia ech do monitorowania zmian temperatury podczas ultradźwiękowego nagrzewania tkanki in vitro. Dane uzyskane drogą pomiarów ultradźwiękowych zostały przetworzone w celu wyznaczenia mapy przemieszczeń ech i odniesione do pomiarów rozkładu temperatury przeprowadzonych za pomocą termopar. Uzyskane wyniki umożliwiają ocenę pola temperatury i pozytywnie rokują połączeniu ultradźwiękowych technik nagrzewania i szacowania lokalnej temperatury tkanki.

Keywords:
obrazowanie temperatury, prędkość akustyczna

Affiliations:
Karwat P. - IPPT PAN
Litniewski J. - IPPT PAN
Secomski W. - IPPT PAN
Kujawska T. - IPPT PAN
Krawczyk K. - IPPT PAN
Kruglenko E. - IPPT PAN
Gambin B. - IPPT PAN
Nowicki A. - IPPT PAN
14.  Karwat P., Litniewski J., Secomski W., Kujawska T., Krawczyk K., Kruglenko E., Gambin B., Non-invasive imaging of thermal fields induced in soft tissues in vitro by focused ultrasound using analysis of ultrasonic echoes displacement, International Conference Biomedical Engineering, 2012-10-25/10-26, Kaunas (LT), pp.66-72, 2012

Abstract:
Therapeutic and surgical applications of focused ultrasound require monitoring of local temperature rises induced inside tissues. From an economic and practical point of view ultrasonic imaging techniques seem to be the best for a temperature control. In this work an attempt to apply the method of the ultrasonic echoes displacement estimation for monitoring local temperature rises in tissues during their heating by focused ultrasound is presented. The estimated temperature rise was compared with this measured by a thermocouple. The obtained results enable to evaluate the temperature fields induced in tissues by pulsed focused ultrasonic beams using non-invasive imaging ultrasound technique.

Keywords:
HIFU, therapeutic ultrasound, ultrasonic imaging, echo strain estimation

Affiliations:
Karwat P. - IPPT PAN
Litniewski J. - IPPT PAN
Secomski W. - IPPT PAN
Kujawska T. - IPPT PAN
Krawczyk K. - IPPT PAN
Kruglenko E. - IPPT PAN
Gambin B. - IPPT PAN
15.  Lewandowski M., Klimonda Z., Karwat P., Sęklewski M., Nowicki A., Bassi L., Tortoli P., Comparison of different schemes of synthetic transmit aperture using an ultrasound advanced open platform (ULA-OP), IUS 2010, IEEE International Ultrasonics Symposium, 2010-10-11/10-14, San Diego (US), DOI: 10.1109/ULTSYM.2010.5935656, Vol.1, pp.1988-1991, 2010

Abstract:
Increasing efforts are currently dedicated to incorporate the Synthetic Transmit Aperture (STA) method in ultrasound imaging systems. The STA technique can provide a pixel-like focusing (dynamic focusing at both transmit and receive) without impairment of the frame rate. This goal can only be achieved by a careful design of the transmission and reception schemes. In this paper, the preliminary results of resolution, Signal to Noise Ratio (SNR) and Contrast to Noise Ratio (CNR) measurements for a specific SA scheme with different transmit apertures are presented. The measurements were made using a novel ultrasound advanced open platform (ULA-OP) developed at the University of Florence. The ULA-OP is fully programmable and enables access to the RF echo-data from each transducer element.

Keywords:
synthetic aperture, ultrasound open platform

Affiliations:
Lewandowski M. - IPPT PAN
Klimonda Z. - IPPT PAN
Karwat P. - IPPT PAN
Sęklewski M. - IPPT PAN
Nowicki A. - IPPT PAN
Bassi L. - other affiliation
Tortoli P. - other affiliation
16.  Walczak M., Kulesza P., Lewandowski M., Karwat P., Witek B., Implementacja w układzie FPGA wybranego filtru ech stałych dla wielobramkowego systemu Dopplera przezczaszkowego, 57 Otwarte Seminarium z Akustyki, 2010-09-20/09-24, Gliwice (PL), pp.209-212, 2010

Abstract:
W artykule opisano wybór i implementację filtrów ech stałych w programowalnych układach logicznych (FPGA) dla ultradźwiękowego wielobramkowego systemu przezczaszkowego przepływomierza krwi opracowywanego w Zakładzie Ultradźwięków IPPT PAN. Implementacja filtrów w FPGA miała na celu redukcję obciążenia softwarowego przetwarzania sygnałów dopplerowskich. W pracy przedstawiono badania modelowe i porównanie filtrów ech stałych o skończonej odpowiedzi impulsowej (SOI) oraz nieskończonej odpowiedzi impulsowej (NOI). Przeanalizowany został zakres stabilnej pracy filtru NOI. Wyselekcjonowany filtr górnoprzepustowy typu SOI został następnie zaimplementowany i zoptymalizowany do architektury układów FPGA oraz zastosowania w przepływomierzu. Zastosowano ekonomiczny układ FPGA Altera Cyclone III EP3C25F324C8. Opracowany filtr ech stałych realizuje 100 identycznych górnoprzepustowych filtrów typu SOI, co zapewnia filtrowanie sygnału dopplerowskiego w 100 bramkach jednocześnie. Filtry operują na 16 bitowych próbkach sygnału, a ich charakterystyka jest programowalna przez 65 16-bitowych współczynników. Zweryfikowano poprawność przetwarzania na komputerze PC w środowisku Altera Quartus II 9.1 oraz ModelSim 6.5b poprzez symulacje i porównanie odpowiedzi impulsowej oraz skokowej filtrów. W wyniku opisanych prac powstała struktura logiczna filtru ech stałych przeznaczona do implementacji w układzie FPGA Cyclone III, zajmująca 5% zasobów logicznych układu oraz 34% zasobów pamięciowych.

Keywords:
ultradźwiękowy Doppler przezczaszkowy, filtry ech stałych, cyfrowe przetwarzanie, FPGA

Affiliations:
Walczak M. - IPPT PAN
Kulesza P. - IPPT PAN
Lewandowski M. - IPPT PAN
Karwat P. - IPPT PAN
Witek B. - IPPT PAN
17.  Sęklewski M., Karwat P., Klimonda Z., Lewandowski M., Nowicki A., Preliminary results: analysis of Synthetic Transmit Aperture technique in ultrasonic imaging, 57 Otwarte Seminarium z Akustyki, 2010-09-20/09-24, Gliwice (PL), pp.173-176, 2010

Abstract:
The Synthetic Aperture (SA) methods are widespread and successfully used in radar technology, as well as in the sonar systems. The advantages of relatively good resolution in the whole area of scanning without decrease of framerate, make this technique an object of interest in medical imaging methods such as ultrasonography (US).This paper describes the possible usage of the SA method in ultrasound imaging. The measurements of different SA schemes were conducted using the set-up consisting of the research ultrasonograph module, the PC and the special wire phantom. The results for different schemes of image reconstruction are presented. Particularly the Synthetic Transmit Aperture (STA) technique was concerned. Results of the STA method are discussed in this paper.

Keywords:
ultrasonic imaging, synthetic aperture focusing technique

Affiliations:
Sęklewski M. - IPPT PAN
Karwat P. - IPPT PAN
Klimonda Z. - IPPT PAN
Lewandowski M. - IPPT PAN
Nowicki A. - IPPT PAN
18.  Karwat P., Klimonda Z., Sęklewski M., Lewandowski M., Nowicki A., Metoda przerzedzania danych dla algorytmu syntetycznej apertury nadawczej, 57 Otwarte Seminarium z Akustyki, 2010-09-20/09-24, Gliwice (PL), pp.91-94, 2010

Abstract:
Metody ultradźwiękowego obrazowania struktur wewnętrznych człowieka są nieustannie ulepszane. Opracowywane są nowe algorytmy umożliwiające poprawę niektórych parametrów wynikowych. Przykładem jest metoda syntetycznej apertury (SA), która pozwala wyświetlać obrazy o wysokiej rozdzielczości z większą częstotliwością niż standardowa metoda formowania wiązki.
Ograniczeniem metody SA jest większa złożoność obliczeniowa, która przy znacznej ilości danych może uniemożliwić osiągnięcie pożądanej szybkości rekonstrukcji. Problem ten można ominąć rezygnując z części zarejestrowanych sygnałów. Wiąże się to oczywiście z pogorszeniem jakości obrazowania, jednak przy odpowiedniej technice przerzedzania danych degradacja obrazu jest niewielka. Proponowany sposób przerzedzania ma zastosowanie w metodzie syntetycznej apertury nadawczej (STA) i opiera się na założeniu, że sygnał uzyskany za pomocą dowolnej pary przetworników jest taki sam niezależnie od tego, który z przetworników nadawał, a który odbierał. W tej sytuacji można pominąć blisko połowę zapisanych danych i wciąż
możliwe będzie zrekonstruowanie obrazu w poprzedniej jakości. Na podstawie prezentowanych wyników symulacji oraz pomiarów na fantomach nitkowym i tkankowym wykazano, że stosując opisaną technikę przerzedzania można zmniejszyć o połowę ilość danych przy zachowaniu rozdzielczości i nieznacznym spadku parametru SNR oraz kontrastu rekonstruowanych obrazów.

Keywords:
metody syntetycznej apertury, przerzedzanie danych

Affiliations:
Karwat P. - IPPT PAN
Klimonda Z. - IPPT PAN
Sęklewski M. - IPPT PAN
Lewandowski M. - IPPT PAN
Nowicki A. - IPPT PAN

Conference abstracts
1.  Dobruch-Sobczak K., Piotrzkowska-Wróblewska H., Klimonda Z., Karwat P., Litniewski J., Roszkowska-Purska K., Markiewicz-Grodzicka E., Quantitative ultrasound parameters assessment of advanced breast cancer in evaluation the response to neoadjuvant chemotherapy, 11TH EUROPEAN BREAST CANCER CONFERENCE, 2018-03-21/03-23, Barcelona (ES), DOI: 10.1016/S0959-8049(18)30674-9, Vol.92, pp.149-150, 2018

Abstract:
Background: Monitoring of response to neoadjuvant chemotherapy (NAC) in advanced breast cancer is crucial for assessing the effectiveness of the treatment and overall survival. The purpose of this study was to investigate the ability of classical ultrasound (US) examination and quantitative ultrasound (QU) parameters to predict the therapy response comparing to histology results after surgical treatment. Material and Methods: Two ultrasound backscatter parameters: the integrated backscatter coefficient, (IBSC) and shape parameter (M) of the homodyned K distribution, were estimated from ultrasonic radiofrequency (RF) signals. Sixteen patient with 22 breast cancer tumor treated with NAC sequential Anthracyclines and Taxanes were prospectively assessed. Data were acquired using 5–14 MHz array transducer, pre-chemotherapy, and four times during treatment (one week after the subsequent courses). The US results were compared with histological response analyzing the stromal changes and the cellularity of the tumor. Results: An increase in IBSC and decrease M parameters was observed in 80% of tumors with complete response after chemotherapy. It correlates with increasing the stromal elements, fibrosis, and elastosis. In patients with partial response, the parameters IBSC and M parameters did not change during subsequent cycles of treatment and allow predicting partial response in 70% of tumors. In pathological results, a similar cluster of cells without fibrosis and elastosis were observed. Conclusions: Ultrasound parameters derived from the RF data give the promise to predict the tumor response to NAC and better personalize the therapy using US QU examination. This study was supported by the National Science Centre, Poland, grant 2016/23/B/ST8/03391. No conflict of interest

Affiliations:
Dobruch-Sobczak K. - other affiliation
Piotrzkowska-Wróblewska H. - IPPT PAN
Klimonda Z. - IPPT PAN
Karwat P. - IPPT PAN
Litniewski J. - IPPT PAN
Roszkowska-Purska K. - other affiliation
Markiewicz-Grodzicka E. - Oncology Institute (PL)
2.  Litniewski J., Klimonda Z., Karwat P., Piotrzkowska-Wróblewska H., Dobruch-Sobczak K., Tymkiewicz R., Gambin B., Cancer Malignancy Sonic Markers, OSA 16, LXIII Otwarte Seminarium z Akustyki, 2016-09-13/09-16, Białowieża (PL), DOI: 10.1515/aoa-2016-0059, No.3, pp.622, 2016
3.  Karwat P., Computationally efficient method for reconstruction of sound speed in soft tissues, OSA 16, LXIII Otwarte Seminarium z Akustyki, 2016-09-13/09-16, Białowieża (PL), pp.619, 2016
4.  Gambin B., Kruglenko E., Secomski W., Karwat P., Temperature dependencies of ultrasound signals backscattered from an agar-oil soft-tissue mimicking material, PCM-CMM 2015, 3rd Polish Congress of Mechanics and 21st Computer Methods in Mechanics, 2015-09-08/09-11, Gdańsk (PL), pp.215-216, 2015

Abstract:
Tissue mimicking materials for ultrasound research, phantoms, should be acousticaly similar to the tissues. Such requirements are filled by the AGO (agar-oil) phantoms. Here, they have been used in experiment of heating internal region of samples by the high intensity ultrasound (HIFU) transducer. During heating the RF (radio frequency) ultrasound signals have been collected. It is demonstrated that the temperature changes in AGO phantoms can be described by the special properties of the backscattered RF signals, namely the shape parameter of the Nakagami distribution and SNR (signal to noise ratio) of signal envelopes random distribution. Reveal of qualitative relationships between the temperature increase/decrease measured by thermocouples and the statistical parameters changes are the main result of the paper.

Keywords:
soft tissue phantom, absorption of acoustic energy, temperature marker, signal-to-noise ratio, Nakagami distribution

Affiliations:
Gambin B. - IPPT PAN
Kruglenko E. - IPPT PAN
Secomski W. - IPPT PAN
Karwat P. - IPPT PAN
5.  Lewandowski M., Walczak M., Karwat P., Witek B., Nowicki A., Karłowicz P., Research & Medical Doppler platform, 11th Congrès Français d'Acoustique, 2012 IOA annual meeting, 2012-04-23/04-27, Nantes (FR), pp.x1-x6, 2012

Abstract:
A new ultrasound digital transcranial Doppler system (digiTDS) is introduced. The digiTDS enables diagnosis of intracranial vessels which are difficult to penetrate for standard systems. The device can display a color map of flow velocities in time-depth domain and a spectrogram of a Doppler signal received from a particular depth. The system offers a multigate processing that allows to display simultaneously a number of spectrograms and to reconstruct a flow velocity profile. The digital signal processing in digiTDS is partitioned between hardware and software parts. The hardware part (based on FPGA) executes a signal demodulation and reduces data stream. The software part (PC) performs the Doppler processing and display tasks. The hardware-software partitioning allowed to build a flexible Doppler platform at a relatively low cost. The digiTDS design fulfills all necessary medical standards being a new useful tool in transcranial field as well as in heart velocimetry research.

Keywords:
ultrasound transcranial Doppler, RF signal processing, DSP, FPGA

Affiliations:
Lewandowski M. - IPPT PAN
Walczak M. - IPPT PAN
Karwat P. - IPPT PAN
Witek B. - IPPT PAN
Nowicki A. - IPPT PAN
Karłowicz P. - Sonomed Sp. z o.o. (PL)

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