1. |
Karwat P., Piotrzkowska-Wróblewska H.E., Klimonda Z., Dobruch-Sobczak K., Litniewski J., Monitoring Breast Cancer Response to Neoadjuvant Chemotherapy Using Probability Maps Derived from Quantitative Ultrasound Parametric Images,
Ieee Transactions on Biomedical Engineering, ISSN: 0018-9294, DOI: 10.1109/TBME.2024.3383920, Vol.71, No.9, pp.2620-2629, 2024Abstract: Objective: Neoadjuvant chemotherapy (NAC) is widely used in the treatment of breast cancer. However, to date, there are no fully reliable, non-invasive methods for monitoring NAC. In this article, we propose a new method for classifying NAC-responsive and unresponsive tumors using quantitative ultrasound. Methods: The study used ultrasound data collected from breast tumors treated with NAC. The proposed method is based on the hypothesis that areas that characterize the effect of therapy particularly well can be found. For this purpose, parametric images of texture features calculated from tumor images were converted into NAC response probability maps, and areas with a probability above 0.5 were used for classification. Results: The results obtained after the third cycle of NAC show that the classification of tumors using the traditional method (AUC = 0.81 - 0.88) can be significantly improved thanks to the proposed new approach (AUC = 0.84–0.94). This improvement is achieved over a wide range of cutoff values (0.2-0.7), and the probability maps obtained from different quantitative parameters correlate well. Conclusion: The results suggest that there are tumor areas that are particularly well suited to assessing response to NAC. Significance: The proposed approach to monitoring the effects of NAC not only leads to a better classification of responses, but also may contribute to a better understanding of the microstructure of neoplastic tumors observed in an ultrasound examination.
Keywords: breast cancer,neoadjuvant chemotherapy,quantitative ultrasound,treatment monitoring. Affiliations:
Karwat P. | - | IPPT PAN | Piotrzkowska-Wróblewska H.E. | - | IPPT PAN | Klimonda Z. | - | IPPT PAN | Dobruch-Sobczak K. | - | IPPT PAN | Litniewski J. | - | IPPT PAN |
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2. |
Nowicki A., Tasinkiewicz J., Karwat P., Trots I., Żołek N.S., Tymkiewicz R., Ultrasound Imaging of Nonlinear Media Response Using a Pressure-Dependent Nonlinearity Index,
ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.24425/aoa.2024.148814, Vol.4, pp.1-7, 2024Keywords: ultrasound imaging,abdominal ultrasound,nonlinear propagation,tissue harmonic imaging,nonlinearity index Affiliations:
Nowicki A. | - | IPPT PAN | Tasinkiewicz J. | - | IPPT PAN | Karwat P. | - | IPPT PAN | Trots I. | - | IPPT PAN | Żołek N.S. | - | IPPT PAN | Tymkiewicz R. | - | IPPT PAN |
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3. |
Karwat P., Algorithm for Computationally Efficient Imaging of Sound Speed in Conventional Ultrasound Sonography,
ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.24425/aoa.2023.146815, Vol.48, No.4, pp.549-558, 2023Abstract: The speed of sound (SoS) in tissues reflects their mechanical properties and therefore can carry valuable
diagnostic information. In conventional ultrasound sonography (US), however, this information is not readily
available. Furthermore, since the actual SoS is unknown, image reconstruction is carried out using an average
SoS value for soft tissues. The resulting local deviations from the actual SoS lead to aberrations in US im-
ages. Methods for SoS imaging in US therefore have the potential to enable the correction of aberrations in
classical US. In addition, they could also become a new US modality.
There are several approaches to SoS image reconstruction. They differ in terms of input data requirements,
computational complexity, imaging quality, and the potential for signal analysis at the intermediate stages of
processing. This article presents an algorithm with multi-stage processing and low computational complexity.
The algorithm was verified through numerical simulations and phantom measurements. The obtained results show that it can correctly estimate SoS in layered media, which in most cases model the tissue structure well.
With its computational complexity of O(n), the algorithm can be implemented in real-time ultrasound imaging
systems with limited hardware performance, such as portable ultrasound devices. Keywords: speed of sound,ultrasound imaging,computational complexity Affiliations:
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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--, 2023Abstract: 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 |
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5. |
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, 2023Abstract: 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 |
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6. |
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, 2022Abstract: 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 |
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7. |
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, 2022Abstract: 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 |
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8. |
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, 2021Abstract: 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 |
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9. |
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, 2021Abstract: 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 |
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10. |
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, 2021Abstract: 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 |
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11. |
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, 2019Abstract: 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 |
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12. |
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, 2019Abstract: 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 |
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13. |
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, 2019Abstract: 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 |
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14. |
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, 2016Abstract: 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 |
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15. |
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, 2016Abstract: 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) |
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16. |
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, 2016Abstract: 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 |
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17. |
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, 2014Abstract: 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 |
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18. |
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, 2014Abstract: 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 |
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19. |
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, 2013Abstract: 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) |
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20. |
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, 2010Abstract: 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 |
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21. |
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, 2010Abstract: 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 |
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22. |
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, 2009Abstract: 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 |
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