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Tytuł:
The influence of the transducer bandwidth and double pulse transmission on the encoded imaging ultrasound
Autorzy:
Trots, I.
Nowicki, A.
Lewandowski, M.
Secomski, W.
Litniewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/331651.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
encoded imaging ultrasound
ultrasound imaging transducer
CGS
Opis:
An influence effect of fractional bandwidth of ultrasound imaging transducer on the gain of compressed echo signal being the complementary Golay sequences (CGS) with different spectral widths is studied in this paper. Also, a new composing transmission method of CGS is discussed together with compression technique applied in order to increase the signal-to-noise ratio (SNR) and penetration. The CGS with two different bit lengths, one-cycle and two-cycles are investigated. Two transducers with fractional bandwidth of 25% and 80% at centre frequency 6 MHz are used. The experimental results are presented, clearly proofing that increasing of the code length leads to compressed echo amplitude enhancement. The smaller the bandwidth is the larger is this effect; the pulse-echo sensitivity of the echo amplitude increases by 1.88 for 25% fractional bandwidth and 1.47 for 80% while preserving time resolution. The presented results of double transmission of short codes show the penetration and SNR improvement while maintaining dead zone.
Źródło:
Hydroacoustics; 2008, 11; 419-430
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ultrasonographic criteria of cesarean scar defect evaluation
Ultrasonograficzne kryteria oceny blizny po cięciu cesarskim
Autorzy:
Woźniak, Andrzej
Pyra, Krzysztof
Rio Tinto, Hugo
Woźniak, Sławomir
Powiązania:
https://bibliotekanauki.pl/articles/1033144.pdf
Data publikacji:
2018
Wydawca:
Medical Communications
Tematy:
caesarean section
scars
ultrasound imaging
Opis:
Cesarean sections account for approximately 20% of all deliveries worldwide. In Poland, the percentage of women delivering by cesarean section amounts to over 43%. According to studies, the prevalence of cesarean scar defects ranges from 24–70%. Due to the overall cesarean section rate, this is a medical problem affecting a large population of women. In such cases, ultrasonographic evaluation of a cesarean scar reveals a hypoechoic space filled with postmenstrual blood, representing a myometrial tear at the wound site. Such an ultrasound appearance is referred to as a niche, and it forms after a cesarean section at the site of the hysterotomy of the anterior uterine wall, most commonly within the uterine isthmus. Currently, the exact cause of niche formation remains unexplained, yet the risk factors for its development are universally acknowledged. They include the site of hysterotomy, multiple previous cesarean section deliveries, suturing technique and maternal diabetes or smoking. Ultrasound evaluation of the cesarean section scar is an important element of obstetric and gynecologic practice, especially in the case of further pregnancies. It facilitates an early diagnosis of a cesarean scar ectopic pregnancy, and the prediction of the risk for perinatal dehiscence in the case of a vaginal birth after a cesarean section.
Około 20% porodów na świecie odbywa się przez cesarskie cięcie. W Polsce odsetek kobiet rodzących tą metodą sięga ponad 43%. Badania dowodzą, że nieprawidłowości w obrębie blizny po cięciu cesarskim występują z częstością 24–70%. Z uwagi na całkowitą liczbę cięć cesarskich problem nieprawidłowego tworzenia się blizny po tym zabiegu przybiera ogromną skalę. Podczas badania ultrasonograficznego widoczna jest hipoechogeniczna przestrzeń wypełniona krwią pomenstruacyjną, odzwierciedlająca przerwanie myometrium w miejscu uprzedniego cięcia cesarskiego. Obraz ten nazywany jest niszą. Formuje się ona po cięciu cesarskim w miejscu histerotomii przedniej ściany macicy, najczęściej w obrębie cieśni macicy. Nie jest obecnie znana dokładna przyczyna występowania niszy, wiadomo jednak, jakie czynniki mają wpływ na jej powstawanie. Najważniejsze z nich to: miejsce wykonania histerotomii, liczba cięć cesarskich, technika szycia oraz czynniki zależne od samej pacjentki, takie jak cukrzyca czy palenie tytoniu. Ultrasonograficzna ocena blizny po cięciu cesarskim jest istotna w praktyce ginekologiczno-położniczej, szczególnie w przypadku ciąży. Daje możliwość wczesnej diagnostyki ciąży w bliźnie po cięciu cesarskim, a w przypadku planowanego porodu siłami natury umożliwia predykcję ryzyka okołoporodowego rozejścia się blizny po cięciu cesarskim.
Źródło:
Journal of Ultrasonography; 2018, 18, 73; 162-165
2451-070X
Pojawia się w:
Journal of Ultrasonography
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multi-Element Synthetic Transmit Aperture in Medical Ultrasound Imaging
Autorzy:
Trots, I.
Nowicki, A.
Lewandowski, M.
Tasinkevych, Y.
Powiązania:
https://bibliotekanauki.pl/articles/177855.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ultrasound imaging
synthetic aperture
beamforming
Opis:
Synthetic aperture (SA) technique is a novel approach to present day commercial systems and has previously not been used in medical ultrasound imaging. The basic idea of SA is to combine information acquired simultaneously from all directions over a number of emissions and to reconstruct the full image from these data. The paper presents the multi-element STA (MSTA) method for medical ultrasound imaging. The main difference with the STA approach is the use of a few elements in the transmit mode in contrast to a single element aperture. This allows increasing the system frame rate, decreasing the number of emissions, and provides the best compromise between the penetration depth and lateral resolution. Besides, a modified MSTA is proposed with a corresponding RF signal correction in the receive mode, which accounts for the element directivity property. In the experiments a 32-element linear transducer array with 0.48 mm interelement spacing and a burst pulse of 100 ns duration were used. Two elements wide transmission aperture was used to generate an ultrasound wave covering the full image region. The comparison of 2D ultrasound images of a tissue mimicking phantom obtained using the STA and MSTA methods is presented to demonstrate the benefits of the second one.
Źródło:
Archives of Acoustics; 2010, 35, 4; 687-699
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multimodal Ultrasonic Imaging for Breast Cancer Detection
Autorzy:
Camacho, J.
Medina, L.
Cruza, J. F.
Moreno, J. M.
Fritsch, C.
Powiązania:
https://bibliotekanauki.pl/articles/176695.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ultrasound imaging
ultrasound tomography
breast cancer
Opis:
Ultrasound is used for breast cancer detection as a technique complementary to mammography, the standard screening method. Current practice is based on reflectivity images obtained with conventional instruments by an operator who positions the ultrasonic transducer by hand over the patient’s body. It is a non-ionizing radiation, pain-free and not expensive technique that provides a higher contrast than mammography to discriminate among fluid-filled cysts and solid masses, especially for dense breast tissue. However, results are quite dependent on the operator’s skills, images are difficult to reproduce, and state-of-the-art instruments have a limited resolution and contrast to show micro-calcifications and to discriminate between lesions and the surrounding tissue. In spite of their advantages, these factors have precluded the use of ultrasound for screening. This work approaches the ultrasound-based early detection of breast cancer with a different concept. A ring array with many elements to cover 360. around a hanging breast allows obtaining repeatable and operator-independent coronal slice images. Such an arrangement is well suited for multi-modal imaging that includes reflectivity, compounded, tomography, and phase coherence images for increased specificity in breast cancer detection. Preliminary work carried out with a mechanical emulation of the ring array and a standard breast phantom shows a high resolution and contrast, with an artifact-free capability provided by phase coherence processing.
Źródło:
Archives of Acoustics; 2012, 37, 3; 253-260
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of the Multi-element Synthetic Transmit Aperture Method for Medical Ultrasound Imaging Applications
Autorzy:
Tasinkevych, Y.
Trots, I.
Nowicki, A.
Lewandowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/177208.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ultrasound imaging
synthetic aperture
beamforming
Opis:
The paper presents the optimization problem for the multi-element synthetic transmit aperture method (MSTA) in ultrasound imaging applications. The optimal choice of the transmit aperture size is made as a trade-off between the lateral resolution, penetration depth and the frame rate. Results of the analysis obtained by a developed optimization algorithm are presented. The maximum penetration depth and lateral resolution at given depths are chosen as optimization criteria. The results of numerical experiments carried out in MATLAB Ž using synthetic aperture data of point reflectors obtained by the FIELD II simulation program are presented. The visualization of experimental synthetic aperture data of a tissue mimicking phantom and in vitro measurements of the beef liver performed using the SonixTOUCH Research system are also shown.
Źródło:
Archives of Acoustics; 2012, 37, 1; 47-55
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Algorithm for Computationally Efficient Imaging of Sound Speed in Conventional Ultrasound Sonography
Autorzy:
Karwat, Piotr
Powiązania:
https://bibliotekanauki.pl/articles/31339779.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
speed of sound
ultrasound imaging
computational complexity
Opis:
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 images. 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.
Źródło:
Archives of Acoustics; 2023, 48, 4; 549-558
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of the image compounding methods for the multi-angle 3-D ultrasound imaging
Autorzy:
Sabiniok, Maciej
Opieliński, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/128271.pdf
Data publikacji:
2019
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
Multi-Angle Conventional Ultrasound Imaging
3D ultrasound imaging
image compounding
soft tissue
ultradźwiękowe obrazowanie 3D
tkanka miękka
Opis:
The main goal of the paper is to compare the image compounding methods to minimise the artefacts arising in the Multi-Angle Conventional Ultrasound Imaging (MACUI) due to the system configuration. The MACUI method used for 3-D object imaging and the introduced imaging artefacts are described. Different ways of the image compounding by intensity averaging are presented in the work. Implemented methods of image compounding were tested for different types of objects mimicking soft tissue. The comparison allowed to determine the most appropriate method of intensity averaging in the compounding method. The method can be used to reduce the presence of image artefacts and enhance the quality of the resulting slices which are used to create 3-D volume of an object structure in MACUI method.
Źródło:
Vibrations in Physical Systems; 2019, 30, 1; 1-8
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthetic Aperture Cardiac Imaging with Reduced Number of Acquisition Channels. A Feasibility Study
Autorzy:
Tasinkevych, Y.
Lewandowski, M.
Klimonda, Z.
Walczak, M.
Powiązania:
https://bibliotekanauki.pl/articles/177629.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
phased-array
ultrasound imaging
diverging wave
synthetic transmit aperture
Opis:
Commercially available cardiac scanners use 64-128 elements phased-array (PA) probes and classical delay-and-sum beamforming to reconstruct a sector B-mode image. For portable and hand-held scanners, which are the fastest growing market, channel count reduction can greatly decrease the total power and cost of devices. The introduction of ultra-fast imaging methods based on plane waves and diverging waves provides new insight into heart’s moving structures and enables the implementation of new myocardial assessment and advanced flow estimation methods, thanks to much higher frame rates. The goal of this study was to show the feasibility of reducing the channel count in the diverging wave synthetic aperture image reconstruction method for phased-arrays. The application of ultra-fast 32-channel subaperture imaging combined with spatial compounding allowed the frame rate of approximately 400 fps for 120 mm visualization to be achieved with image quality obtained on par with the classical 64-channel beamformer. Specifically, it was shown that the proposed method resulted in image quality metrics (lateral resolution, contrast and contrast-to-noise ratio), for a visualization depth not exceeding 50 mm, that were comparable with the classical PA beamforming. For larger visualization depths (80-100 mm) a slight degradation of the above parameters was observed. In conclusion, diverging wave phased-array imaging with reduced number of channels is a promising technology for low-cost, energy efficient hand-held cardiac scanners.
Źródło:
Archives of Acoustics; 2018, 43, 3; 437-446
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mutually Orthogonal Golay Complementary Sequences in Medical Ultrasound Diagnostics. Experimental Study
Autorzy:
Trots, Ihor
Żołek, Norbert
Tasinkevych, Yuriy
Wójcik, Janusz
Powiązania:
https://bibliotekanauki.pl/articles/31340110.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
coded excitation
mutually orthogonal Golay codes
synthetic aperture
ultrasound imaging
Opis:
The objective of this paper is an experimental study of the most crucial parameters of the received acoustic signals (e.g. signal-to-noise ratio (SNR), side-lobes level (SLL), axial resolution) obtained as a result of simultaneous emission of mutually orthogonal Golay complementary sequences (MOGCS) to demonstrate their feasibility of being used in ultrasound diagnostics. Application of the MOGCS in ultrasound measurements allows the image reconstruction time to be shortened without decreasing the resulting quality of reconstructed images in comparison with regular complementary Golay coded sequences (CGCS). In this paper two sets of 16-bits long MOGCS were implemented in the Verasonics Vantage™ (Verasonics Inc., Kirkland, WA, USA) scanner. Ultrasound data were generated using a perfect reflector, a custom-made nylon wire phantom and tissue mimicking phantom. Parameters of the detected MOGCS echoes like SNR, SLL and axial resolution were determined and compared to that of the standard CGCS and the short two-sine cycles pulse. It was evidenced that applying MOGCS did not compromise the parameters of the separated and compressed echoes in comparison to the other types of transmitted signal – the CGCS and the short pulse. Concretely, both the MOGCS and CGCS yield similar SNR increase in comparison to the short pulse. Almost similar values of the axial resolution estimated at the full width at the half maximum level for all types of the transmitted signals were also obtained. At the same time, using the MOGCS the data acquisition speed can be increased twice in comparison with the CGCS signal.
Źródło:
Archives of Acoustics; 2022, 47, 3; 399-405
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mutually Orthogonal Golay Complementary Sequences in Synthetic Aperture Imaging Systems
Autorzy:
Trots, I.
Powiązania:
https://bibliotekanauki.pl/articles/178145.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
coded excitation
mutually orthogonal Golay codes
synthetic aperture
ultrasound imaging
Opis:
The main objective of this study is to improve the ultrasound image by employing a new algorithm based on transducer array element beam pattern correction implemented in the synthetic transmit aperture (STA) method combined with emission of mutually orthogonal complementary Golay sequences. Orthogonal Golay sequences can be transmitted and received by different transducer elements simultaneously, thereby decreasing the time of image reconstruction, which plays an important role in medical diagnostic imaging. The paper presents the preliminary results of computer simulation of the synthetic aperture method combined with the orthogonal Golay sequences in a linear transducer array. The transmission of long waveforms characterized by a particular autocorrelation function allows to increase the total energy of the transmitted signal without increasing the peak pressure. It can also improve the signal-to-noise ratio and increase the visualization depth maintaining the ultrasound image resolution. In the work, the 128-element linear transducer array with a 0.3 mm pitch excited by 8-bits Golay coded sequences as well as one cycle at nominal frequencies of 4 MHz were used. The comparison of 2D ultrasound images of the phantoms is presented to demonstrate the benefits of a coded transmission. The image reconstruction was performed using the synthetic STA algorithm with transmit and receive signals correction based on a single element directivity function.
Źródło:
Archives of Acoustics; 2015, 40, 2; 283-289
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
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