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1
Content available A method of precise pulse onset determination using the Akaike Information Criterion for Ultrasound Transmission Tomography
Pruchnicki Piotr, Opieliński Krzysztof J.
Vibrations in Physical Systems
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2021
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Vol. 32, nr 1
art. no. 2021115
EN
Information criteria used in statistics for model selection can be used to accurately determine pulse transition times in transmission methods. The most popular information criteria are the Akaike Information Criterion (AIC) and the Bayesian Schwartz Criterion (BIC). These criteria are considered the most reliable tests of model type and structure and are computationally simple. In this paper, an algorithm developed according to the AIC criterion is used to determine the transition time from transmission tomography measurements acquired with a multi-element ultrasonic ring array, which is the scanning element of the novel prototype of ultrasound tomography device for detecting and estimating the malignancy of female breast cancer in vivo. As a result, a new algorithm was developed to precise search for the onset of the recorded receiving pulse. The algorithm was tested in an aqueous environment using elementary pairs of transmitting and receiving ultrasonic transducers of a tomographic ring array.
2
Content available Application of the Ultrasonic Ring Array Used in UTT for the Reflection Method Examinations of Structures
Staszewski Wiktor, Gudra Tadeusz, Opieliński Krzysztof J.
Archives of Acoustics
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2021
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Vol. 46, No. 3
427--434
EN
The ultrasonic ring array, designed for examining the female breast with the use of ultrasonic transmission tomography (UTT), has been adapted for reflection method trials. By altering the activation time of ultrasonic elementary transducers, the parameters of the focus were changed with the aim at improving the quality of the obtained ultrasound image. For this purpose, a phantom consisting of rods having varying thicknesses was analyzed when moving the position of the focus with the use of dynamic focusing along the symmetry axis of the ring array ranging from 30 to 130 mm from central transducers. In previous trials, which applied an algorithm using the sum of all the acoustic fields, a series of simulations was performed in conditions identical to the phantom trial. This paper documents attempts at improving the parameters of the acoustic field distribution during unconventional focusing. The research here presented is a continuation of examinations focusing on the acoustic field distribution inside the ultrasonic ring array with the aim at finding the best possible cross-section of the female breast using the reflection method.
3
Content available Analysis for Improvement of Doppler Tomography Imaging of Objects Scattering Continuous Ultrasonic Waves
Świetlik Tomasz, Opieliński Krzysztof J.
Archives of Acoustics
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2020
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Vol. 45, No. 2
329--339
EN
The paper describes an innovative ultrasound imaging method called Doppler Tomography (DT), otherwise known as Continuous Wave Ultrasonic Tomography (CWUT). Thanks to this method, it is possible to image the tissue cross-section in vivo using a simple two-transducer ultrasonic probe and using the Doppler effect. It should be noted that DT significantly differs from the conventional ultrasound Doppler method of measuring blood flow velocity. The main difference is that when measuring blood flow, we receive information with an image of the velocity distribution in a given blood vessel (Nowicki, 1995), while DT allows us to obtain a cross-sectional image of stationary tissue structure. In the conventional method, the probe remains stationary, while in the DT method, the probe moves and the examined tissue remains stationary. This paper presents a method of image reconstruction using the DT method. First, the basic principle of correlation of generated Doppler frequencies with the location of inclusions from which they originate is explained. Then the exact process and algorithm in this method are presented. Finally, the impact of several key parameters on imaging quality is examined. As a result, the conclusions of the research allow to improve the image reconstruction process using the DT method.
4
Content available Ultrasound tomography imaging: results of breast phantom study and resolution estimation
Opieliński Krzysztof J., Wrzosek Marcin, Nicpoń Józef, Podgórski Przemysław, Świetlik Tomasz
Vibrations in Physical Systems
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2019
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Vol. 30, nr 1
art. no. 2019105
EN
In order to improve breast cancer detection rates, new and better imaging methods are required. Currently, the ultrasound tomography (UT) as non-invasive and safe hybrid method may contribute to achieving a new standard for breast cancer diagnostics. The aim of the paper was to analyse the imaging ability of tissue-like media structure found in female breast using the developed novel ultrasound computer-assisted tomographic scanner. Measurements was performed on commercial breast biopsy phantoms due to their well-defined structure with inclusions mimicking glandular tissue with lesions, as well as on the simple agar phantom. Obtained magnetic resonance images (MRI), conventional ultrasound images (US) or X-ray computed tomography (CT) images of the measured media sections were used for comparison. The analysis of the obtained results and carried out theoretical considerations have allowed to estimate the resolution of soft tissue UT imaging.
5
Content available Model of multipath propagation of ultrasonic pulses in soft tissue using divergent beam tomography method
Borowski Jędrzej, Opieliński Krzysztof J.
Vibrations in Physical Systems
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2019
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Vol. 30, nr 1
art. no. 2019130
EN
The paper presents the model of calculating ultrasound waveform beam emitted inside the circular space of ultrasonic transducer ring array and propagated through a biological medium submerged in water. Each elementary transducer emits a burst signal, which then propagates through a medium and is received by a number of transducers on the opposite side of the ring array. The method allows for calculating runtime and amplitude of ultrasonic bursts while traveling from an emitter to a receiver through a specified soft tissue section geometry, having regard to the refraction and attenuation effects and directivity pattern of transducers. The soft tissue section geometry is constructed using circular shapes with given ultrasound speed and attenuation distribution. The elaborated software creates a set of received waveforms for each transmitting transducer. The presented results produced by the software can be used as a basis for further research on inverse problems in ultrasound waveform tomography.
6
Content available Animal mimicry for covert communication with arbitrary output distribution: beyond the assumption of ignorance
Zuber Krzysztof Władysław, Opieliński Krzysztof J.
Vibrations in Physical Systems
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2019
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Vol. 30, nr 1
art. no. 2019119
EN
The paper describes a new method of embedding human communication in acoustic sequences mimicking animal communication. This is done to ensure a low probability of detection (LPD) transfer of covert messages. The proposed scheme mimics not only individual sounds, but also the imitated species’ communication structure. This paper presents a step forward in animal communication mimicry - from pure vocal imitation without regard for the plausibility of communication’s structure, through Zipf’s law-preserving scheme, to the mimicry of a known communication structure. Unlike previous methods, the updated scheme does not rely on third parties’ ignorance of the imitated species’ communication structure beyond Zipf’s law - instead, the new method enables one to encode information in a known zeroth-order Markov model. The paper describes a method of encoding an arbitrary message in a syntactically plausible, species-specific sequence of animal sounds through evolutionary means. A comparison with the previous iteration of the method is also presented.
7
Content available Analysis of Doppler tomography in circular geometry as a novel method of imaging tissue cross-sections in vivo
Świetlik Tomasz, Opieliński Krzysztof J.
Vibrations in Physical Systems
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2019
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Vol. 30, nr 1
art. no. 2019144
EN
Currently, methods such as conventional ultrasound B-mode scanning (US), computerized X-ray tomography (CT), magnetic resonance imaging (MRI), standard X-ray diagnostics, radioisotope imaging and thermography are used to visualize the internal structure of tissue in vivo and to diagnose the patient. Doppler tomography (DT) is an innovative method of reconstructing the image of the tissue section using ultrasonic waves and Doppler effect. In contrast to the currently applied solutions (US), this method uses a continuous wave, which, in theory, allows one to operate with higher energy and to detect smaller inclusions within the examined tissue. This study focuses on the analysis of DT simulation in circular geometry, where a two-transducer ultrasonic probe circulating around the tested object is used to measure the useful signal. In this paper, the influence on the tested object’s cross-section imaging quality of both the simulated Doppler signal’s registration parameters, and the calculation algorithm’s parameters, were analyzed.
8
Content available The Effect of Dynamic Beam Deflection and Focus Shift on the Acoustic Field Distribution Inside the Ultrasonic Ring Array
Staszewski Wiktor, Gudra Tadeusz, Opieliński Krzysztof J.
Archives of Acoustics
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2019
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Vol. 44, No. 4
625--636
EN
This paper presents the results of acoustic field distribution simulations for the 1024-element ultrasonic ring array intended for the diagnosis of female breast tissue with the use of ultrasound tomography. For the purpose of analysing data, all acoustic fields created by each elementary transducer were combined. The natural position of the focus inside the ultrasonic ring array was changed by altering activation time of individual transducers in sectors consisting of 32, 64, and 128 ultrasonic transducers. Manipulating the position of the focus inside the array will allow to concentrate the ultrasonic beam in a chosen location in the interior space of the ring array. The goal of this research is to receive the best possible quality of images of cross-sections of the female breast. The study also analysed the influence of the acoustic field distribution on the inclination of the beam. The results will enable to choose an optimal focus and an optimal number of activated transducers.
9
Content available Analysis of Using Multi-Angle Conventional Ultrasound Scanning for Efficient 3-D Object Imaging
Sabiniok Maciej, Opieliński Krzysztof J., Lis Sylwia
Archives of Acoustics
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2019
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Vol. 44, No. 4
645--657
EN
The purpose of this work is to examine the possibility of using multi-angle conventional ultrasound B-mode scanning in efficient 3-D imaging. In the paper, the volume of an object is reconstructed from vertical projections registered at fixed angular positions of the multi-element linear ultrasonic probe rotated in relation to the object submerged in water. The possible configurations are: vertical lateral, vertical top or vertical bottom. In the vertical lateral configuration, the ultrasonic probe acquires 2-D images of object’s vertical cross-sections, turning around its lateral surface. In the vertical top or bottom configuration, the ultrasonic probe acquires 2-D images of the object’s vertical cross-sections, turning on the horizontal plane over the top or under the bottom surface of the object. The method of recording 3-D volume of an object’s structure and reconstruction algorithm have been designed. Studies show the method in the vertical top or bottom configuration could be successfully applied to the effective 3-D visualisation of the structure of the female breast in vivo as the new complement ultrasonic imaging modality in the prototype of the developed ultrasound tomography scanner.
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