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    Wyświetlanie 1-11 z 11
    Tytuł:
    Three-dimensional reconstruction and morphometric analysis of the mandible in Van cats: A computed tomography (CT) study
    Autorzy:
    Yilmaz, O.
    Demircioglu, İ.
    Powiązania:
    https://bibliotekanauki.pl/articles/2087193.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    computed tomography
    mandible
    morphometry
    three-dimensional reconstruction
    Van cat
    Źródło:
    Polish Journal of Veterinary Sciences; 2021, 24, 2; 261-270
    1505-1773
    Pojawia się w:
    Polish Journal of Veterinary Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Automatic Extraction of the Pelvicalyceal System for Preoperative Planning of Minimally Invasive Procedures
    Autorzy:
    Heryan, K.
    Skalski, A.
    Jakubowski, J.
    Drewniak, T.
    Gajda, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/220364.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    pelvicalyceal system segmentation
    kidney segmentation
    kidney compartments
    Computed Tomography (CT)
    kidney cancer
    Opis:
    Minimally invasive procedures for the kidney tumour removal require a 3D visualization of topological relations between kidney, cancer, the pelvicalyceal system and the renal vascular tree. In this paper, a novel methodology of the pelvicalyceal system segmentation is presented. It consists of four following steps: ROI designation, automatic threshold calculation for binarization (approximation of the histogram image data with three exponential functions), automatic extraction of the pelvicalyceal system parts and segmentation by the Locally Adaptive Region Growing algorithm. The proposed method was applied successfully on the Computed Tomography database consisting of 48 kidneys both healthy and cancer affected. The quantitative evaluation (comparison to manual segmentation) and visual assessment proved its effectiveness. The Dice Coefficient of Similarity is equal to 0.871 ± 0.060 and the average Hausdorff distance 0.46 ± 0.36 mm. Additionally, to provide a reliable assessment of the proposed method, it was compared with three other methods. The proposed method is robust regardless of the image acquisition mode, spatial resolution and range of image values. The same framework may be applied to further medical applications beyond preoperative planning for partial nephrectomy enabling to visually assess and to measure the pelvicalyceal system by medical doctors.
    Źródło:
    Metrology and Measurement Systems; 2017, 24, 1; 3-18
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The defect analysis of Inconel 738LC with computed tomography inspection
    Autorzy:
    Ciećko, Andrzej
    Kamiński, Łukasz
    Wierzba, Patrycja
    Powiązania:
    https://bibliotekanauki.pl/articles/175802.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    computed tomography
    CT
    material defects
    Inconel 738LC
    tensile test
    chemical analysis
    material properties
    nondestructive
    Inconel
    Opis:
    In the present paper, computed tomography (CT) inspection is shown. The CT inspection method allowed to rate the density of defects hidden inside a material, which has a significant role in the live material. The method allows to evaluate the reliability of tensile test’s results. In our analysis, the position of crack propagation was determined by CT, and the tensile test was performed to check the accuracy of the nondestructive method. The tensile tests were performed on Inconel 738LC [1] samples.
    Źródło:
    Advances in Manufacturing Science and Technology; 2020, 44, 3; 80-83
    0137-4478
    Pojawia się w:
    Advances in Manufacturing Science and Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Methods of reconstructing complex multi-structural anatomical objects with RP techniques
    Autorzy:
    Kudasik, T.
    Miechowicz, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/202044.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    medical modelling
    rapid prototyping
    computed tomography
    CT
    experimental tests
    modelowanie medyczne
    szybkie prototypowanie
    tomografia komputerowa
    badania doświadczalne
    Opis:
    This article presents reconstruction methods applied to a (geometrically and physically) complex structural object with the use of RP and RT techniques. The methods are innovative due to their hybrid - multi-model and multi-material - approach to reconstruction, as well as the application of multiple technologies. An experimental analysis was conducted to verify the feasibility of rapid prototyping (RP) techniques in the reconstruction of complex internal structures using materials of diverse properties. Some RP techniques offer the possibility of discriminating between diverse objects through the use of different colours. Such models are well-suited for diagnostic purposes, for better visualisation of complex clinical problems, pathological alterations, etc. Nevertheless, they fail to fully reflect physical and mechanical properties of objects, which renders them useful in experimental analysis only to a limited extent. Their basic drawback is that they merely reflect geometrical features of the examined object. The methods discussed in the present article enable modelling multi-object structures in a single process based on the PolyJet Matrix technology and materials of different physical properties by means of a hybrid method. The article also describes the process of modelling complex anatomical structures of soft tissues and bones using models of the maxilla and the mandible as examples. The study is based on data acquired through standard computed tomography (CT). In addition, the article addresses selected aspects of CT acquisition, generation of numerical models composed of several anatomical structures (objects) and fabricating physical multi-object models.
    Źródło:
    Bulletin of the Polish Academy of Sciences. Technical Sciences; 2016, 64, 2; 315-323
    0239-7528
    Pojawia się w:
    Bulletin of the Polish Academy of Sciences. Technical Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A Robust CNN Model for Diagnosis of COVID-19 Based on CT Scan Images and DL Techniques
    Autorzy:
    Eldeeb, Ahmed H.
    Amr, Mohammed Nagah
    Ibrahim, Amin S.
    Kamel, Hesham
    Fouad, Sara
    Powiązania:
    https://bibliotekanauki.pl/articles/2200729.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Deep learning
    COVID-19
    Artificial Intelligence
    computed tomography
    Convolutional Neural Networks
    Opis:
    The 2019 Coronavirus (COVID-19) virus has caused damage on people's respiratory systems over the world. Computed Tomography (CT) is a faster complement for RT-PCR during peak virus spread times. Nowadays, Deep Learning (DL) with CT provides more robust and reliable methods for classifying patterns in medical pictures. In this paper, we proposed a simple low training proposed customized Convolutional Neural Networks (CNN) customized model based on CNN architecture that layers which are optionals may be included such as the layer of batch normalization to reduce time taken for training and a layer with a dropout to deal with overfitting. We employed a huge dataset of chest CT slices images from diverse sources COVIDx-CT, which consists of a 16,146-image dataset with 810 patients of various nationalities. The proposed customized model's classification results compared to the VGG-16, Alex Net, and ResNet50 Deep Learning models. The proposed CNN model shows robustness by achieving an overall accuracy of 93% compared to 88%, 89%, and 95% for the VGG-16, Alex Net, and ResNet50 DL models for the classification of 3 classes. When this relates to binary classification, the classification accuracy of the proposed model and the VGG-16 models were identical (almost 100% accurate), with 0.17% of misclassification in the class of Non-Covid-19, the Alex Net model achieved almost 100% classification accuracy with 0.33% misclassification in the class of Non-Covid-19. Finally, ResNet50 achieved 95% classification accuracy with 5% misclassification in the Non-Covid-19 class.
    Źródło:
    International Journal of Electronics and Telecommunications; 2022, 68, 4; 731--739
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Evaluation of skull bone structures in CT imaging
    Autorzy:
    Ryniewicz, Andrzej
    Ryniewicz, Wojciech
    Wyrąbek, Stanisław
    Bojko, Łukasz
    Powiązania:
    https://bibliotekanauki.pl/articles/140116.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    skull
    shape
    imaging precision
    spiral computed tomography
    CT
    reverse engineering
    czaszka
    kształt
    dokładność obrazowania
    spiralna tomografia komputerowa
    inżynieria odwrotna
    Opis:
    At the current stage of diagnostics and therapy, it is necessary to perform a geometric evaluation of facial skull bone structures basing upon virtually reconstructed objects or replicated objects with reverse engineering. The objective hereof is an analysis of imaging precision for cranial bone structures basing upon spiral tomography and in relation to the reference model with the use of laser scanning. Evaluated was the precision of skull reconstruction in 3D printing, and it was compared with the real object, topography model and reference model. The performed investigations allowed identifying the CT imaging accuracy for cranial bone structures the development of and 3D models as well as replicating its shape in printed models. The execution of the project permits one to determine the uncertainty of components in the following procedures: CT imaging, development of numerical models and 3D printing of objects, which allows one to determine the complex uncertainty in medical applications.
    Źródło:
    Archive of Mechanical Engineering; 2019, LXVI, 1; 83-95
    0004-0738
    Pojawia się w:
    Archive of Mechanical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Ultrasound Transmission Tomography Imaging of Structure of Breast Elastography Phantom Compared to US, CT and MRI
    Autorzy:
    Opieliński, K. J.
    Pruchnicki, P.
    Gudra, T.
    Podgórski, P.
    Kraśnicki, T.
    Kurcz, J.
    Sąsiadek, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/176996.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    ultrasound transmission tomography
    UTT
    ultrasonography
    US
    computed tomography
    magnetic resonance
    MR
    mammography
    breast biopsy phantom
    Opis:
    The paper presents an analysis of the results of ultrasound transmission tomography (UTT) imaging of the internal structure of a breast elastography phantom used for biopsy training, and compares them with the results of CT, MRI and, conventional US imaging; the results of the phantom examination were the basis for the analysis of UTT method resolution. The obtained UTT, CT and MRI images of the CIRS Model 059 breast phantom structure show comparable (in the context of size and location) heterogeneities inside it. The UTT image of distribution of the ultrasound velocity clearly demonstrates continuous changes of density. The UTT image of derivative of attenuation coefficient in relation to frequency is better for visualising sharp edges, and the UTT image of the distribution of attenuation coefficient visualises continuous and stepped changes in an indirect way. The inclusions visualized by CT have sharply delineated edges but are hardly distinguishable from the phantom gel background even with increased image contrast. MRI images of the studied phantom relatively clearly show inclusions in the structure. Ultrasonography images do not show any diversification of the structure of the phantom. The obtained examination results indicate that, if the scanning process is accelerated, ultrasound transmission tomography method can be successfully used to detect and diagnose early breast malignant lesions. Ultrasonic transmission tomography imaging can be applied in medicine for diagnostic examination of women’s breasts and similarly for X-ray computed tomography, while eliminating the need to expose patients to the harmful ionising radiation.
    Źródło:
    Archives of Acoustics; 2013, 38, 3; 321-334
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Methods for designing and fabrication large-size medical models for orthopaedics
    Autorzy:
    Kudasik, T.
    Libura, M.
    Markowska, O.
    Miechowicz, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/200776.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    computed tomography
    CT
    orthopaedic surgery
    computer assisted surgery
    CAS
    rapid prototyping
    RP
    Opis:
    Computed tomography and rapid prototyping techniques can be used to construct and fabricate large size bone models for orthopaedics. Rapid Prototyping technology enables the fabrication of a true-to-scale bone joint model based on 3D virtual models, generated by segmenting patients’ CT images. The model can be used to plan, to simulate, to assist prosthesis implantation for difficult cases of THR (Total Hip Replacements). The main restriction of implementing such models into medical practice is high cost of their production. Physical models of pelvic bones, were constructed on the basis of data collected during standard CT examinations. A method of development of a large-size model while fulfilling the requirement for reducing the price of model fabrication in the article was presented. The method can be used for fabrication the models with 3DP technique. This paper also discusses the issue of production costs when utilizing other RP techniques as well as their usefulness in practice.
    Źródło:
    Bulletin of the Polish Academy of Sciences. Technical Sciences; 2015, 63, 3; 623-627
    0239-7528
    Pojawia się w:
    Bulletin of the Polish Academy of Sciences. Technical Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Measurement of the upper respiratory tract aerated space volume using the results of computed tomography
    Autorzy:
    Rybak, Adam
    Zając, Andrzej
    Kukwa, Andrzej
    Powiązania:
    https://bibliotekanauki.pl/articles/221767.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    CT studies
    upper respiratory tract diagnostics
    quantitative measurement of upper respiratory tract aerated space volume
    Opis:
    The paper presents the possibilities of quantitative analysis of results obtained from CT examination of organs and anatomical structures of the upper respiratory tract. The presented results of the analysis were obtained using proprietary software developed in the MATLAB 2018b environment (Image Processing toolbox). The software enables to visualize the original results of CT scan and, after evaluating the visible structures, enables to select the area to be subjected to quantitative analysis. After the initial identification of an area of interest requiring detailed diagnostics, its volume and the surface areas of individual cross-sections are calculated in the area separated for examinations. A graphical presentation of the analysis results - the surface areas of selected cross-sections possible to visualize in two- and three-dimensional space - enables quick analysis of changes in the examined region.
    Źródło:
    Metrology and Measurement Systems; 2019, 26, 2; 387-401
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Semantic segmentation and PSO based method for segmenting liver and lesion from CT images
    Autorzy:
    Nayantara, Vaidehi P.
    Surekha, Kamath
    Manjunath, K.N.
    Rajagopal, Kadavigere
    Powiązania:
    https://bibliotekanauki.pl/articles/2146955.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    liver lesion segmentation
    computed tomography
    semantic segmentation
    SegNet
    particle swarm optimization-based clustering
    Hounsfield Unit
    Opis:
    The liver is a vital organ of the human body and hepatic cancer is one of the major causes of cancer deaths. Early and rapid diagnosis can reduce the mortality rate. It can be achieved through computerized cancer diagnosis and surgery planning systems. Segmentation plays a major role in these systems. This work evaluated the efficacy of the SegNet model in liver and particle swarm optimization-based clustering technique in liver lesion segmentation. Over 2400 CT images were used for training the deep learning network and ten CT datasets for validating the algorithm. The segmentation results were satisfactory. The values for Dice Coefficient and volumetric overlap error achieved were 0.940 ± 0.022 and 0.112 ± 0.038, respectively for liver and the results for lesion delineation were 0.4629 ± 0.287 and 0.6986 ± 0.203, respectively. The proposed method is effective for liver segmentation. However, lesion segmentation needs to be further improved for better accuracy.
    Źródło:
    International Journal of Electronics and Telecommunications; 2022, 68, 3; 635--640
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The accuracy of the reproduction of the lumbar spine elements following CT and MRI projections
    Dokładność odwzorowania elementów segmentu kręgosłupa lędźwiowego po projekcjach tomografii komputerowej i rezonansu magnetycznego
    Autorzy:
    Kroczak, P.
    Skalski, K.
    Nowakowski, A.
    Mróz, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/140161.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    total disc replacement
    human spine
    computed tomography
    magnetic resonance imaging
    3D geometric modelling
    całkowita wymiana dysku
    ludzki kręgosłup
    tomografia komputerowa
    rezonans magnetyczny
    modelowanie geometryczne 3D
    Opis:
    The paper presents an analysis of factors influencing the accuracy of reproduction of geometry of the vertebrae and the intervertebral disc of the lumbar motion segment for the purpose of designing of an intervertebral disc endoprosthesis. In order to increase the functionality of the new type of endoprostheses by a better adjustment of their structure to the patient’s anatomical features, specialist software was used allowing the processing of the projections of the diagnosed structures. Recommended minimum values of projection features were determined in order to ensure an effective processing of the scanned structures as well as other factors affecting the quality of the reproduction of 3D model geometries. Also, there were generated 3D models of the L4-L5 section. For the final development of geometric models for disc and vertebrae L4 and L5 there has been used smoothing procedure by cubic free curves with the NURBS technique. This allows accurate reproduction of the geometry for the purposes of identification of a spatial shape of the surface of the vertebrae and the vertebral disc and use of the model for designing of a new endoprosthesis, as well as conducting strength tests with the use of finite elements method.
    W artykule przedstawiono analizę czynników, które wpływają na dokładność odwzorowania geometrii kręgów i krążka międzykręgowego segmentu ruchowego kręgosłupa lędźwiowego, na potrzeby projektowania endoprotezy krążka międzykręgowego. W celu zwiększenia funkcjonalności nowego typu endoprotez poprzez lepsze dopasowanie ich konstrukcji do cech anatomicznych pacjenta, wykorzystywano specjalistyczne oprogramowanie, które umożliwiło przetwarzanie projekcji zdiagnozowanych struktur. Zgromadzone dane medyczne, pochodzace z projekcji tomografii komputerowej oraz rezonansu magnetycznego zostały opracowane i zestawione w utworzonej bazie danych. Poszczególne zbiory różniły się między sobą właściwościami (rozdzielczością, wielkością pojedynczego piksela, liczbą rastrów, odstępem pomiędzy rastrami oraz grubością rastrów). Na ich podstawie wygenerowano trójwymiarowe modele. Określono zalecane wartości minimalne cech projekcji, które zapewniają efektywne przetwarzanie skanowanych struktur oraz inne czynniki wpływające na jakość odwzorowania geometrii modeli 3D. Do końcowego opracowania modeli geometrycznych krążka oraz kręgów L4 i L5 wykorzystano procedurę wygładzania poprzez kubiczne krzywe swobodne techniką NURBS. Dzięki temu możliwe jest dokładne odwzorowanie geometrii w celu identyfikacji przestrzennego kształtu powierzchni kręgów i krążka międzykręgowego oraz wykorzystania modelu do zaprojektowania nowej endoprotezy, a także do przeprowadzenia badań wytrzymałościowych metodą elementów skończonych.
    Źródło:
    Archive of Mechanical Engineering; 2014, LXI, 4; 523-538
    0004-0738
    Pojawia się w:
    Archive of Mechanical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-11 z 11

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