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Long-term Analysis of Ultrasound Video Sequences Using Interest Point Detectors
Zukal, Martin ; Závodná, Eva (referee) ; Papež,, Václav (referee) ; Říha, Kamil (advisor)
This doctoral thesis deals with the analysis of ultrasound (US) video sequences. It specifically focuses on long-term tracking of the common carotid artery (CCA) in transversal section and measurement of its geometric parameters in a sequence of US images. The design and implementation of a system for automatic tracking of the artery is described in this thesis. The proposed system utilizes Viola-Jones detector and Hough transform to localize the artery in the image. Interest points are detected in the area of the artery wall. These points are then tracked using optical flow. The proposed system comprises a number of innovative methods which allow to perform accurate long-term measurement of parameters of CCA and store the results. A novel mathematical model describing the movement of CCA in transversal section during a cardiac cycle is defined afterwards taking the influence of breathing into consideration. A number of artificial sequences of US images based on this model have been created. These sequences were consequently used to evaluate the accuracy of the proposed system in terms of measuring the parameters of CCA. The sequences are unique because of their length which makes them suitable for evaluation of tracking accuracy even in long video sequences.
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Impact of material properties of tissues on stresses in a pathological carotid artery
Hrubanová, Anna ; Návrat, Tomáš (referee) ; Burša, Jiří (advisor)
This thesis deals with determination of representative constitutive model for describing atherosclerotic carotid artery behavior. The first part of the thesis provides brief summary of medical knowledge needed as well as detailed describtion of current experimental methods for determination of mechanical properties of atherosclerotic arteries. The main part is focused on mechanical testing of atheroslecotic carotid arteries. The description of sample preparation, testing device and the experiment itself is involved. Statistical analysis of measured data is done, focusing on comparison of factors potentially influencing mechanical behavior. In conclusion, the FEA analysis on simplified geometry of carotid artery with atheroma is performed. Emphasis is placed on the impact of material model obtained from experiments on equivalent stress in fibrous cap.
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Influence of calcifications on stress states in arteries
Macůrek, Michal ; Fuis, Vladimír (referee) ; Burša, Jiří (advisor)
The first part of this thesis covers anatomy of blood vessel walls, their material characteristics and their computational modeling. Second part is focused on determining the influence of calcifications on stress states in common carotid artery. In the rest of the thesis, models of plate calcification and spheical calcifications distributed in the circumferential and axial directions of the artery are compared.
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Impact of material properties of tissues on stresses in a pathological carotid artery
Hrubanová, Anna ; Návrat, Tomáš (referee) ; Burša, Jiří (advisor)
This thesis deals with determination of representative constitutive model for describing atherosclerotic carotid artery behavior. The first part of the thesis provides brief summary of medical knowledge needed as well as detailed describtion of current experimental methods for determination of mechanical properties of atherosclerotic arteries. The main part is focused on mechanical testing of atheroslecotic carotid arteries. The description of sample preparation, testing device and the experiment itself is involved. Statistical analysis of measured data is done, focusing on comparison of factors potentially influencing mechanical behavior. In conclusion, the FEA analysis on simplified geometry of carotid artery with atheroma is performed. Emphasis is placed on the impact of material model obtained from experiments on equivalent stress in fibrous cap.
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Common Carotid Artery Wall Localization In B-Mode Ultrasound Images
Dorazil, Jan
Analysis of B-mode ultrasound images capturing the common carotid artery (CCA) provides significant indicators of the overall health of the cardiovascular system. In this paper we propose a novel method for automatic localization of the artery wall contour (approximated by circle) in utrasound images of the transverse section of the CCA. After detection of a region of interest (ROI) using a modified Viola-Jones detector we localize the best-fitting circle, which delimits the artery wall contour, by exhaustive search. Experimental results on a dataset of 145 ultrasound images show that the method outperforms a reference method based on the Hough transform and presents an excellent obustness against additive noise on different SNR levels.
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Long-term Analysis of Ultrasound Video Sequences Using Interest Point Detectors
Zukal, Martin ; Závodná, Eva (referee) ; Papež,, Václav (referee) ; Říha, Kamil (advisor)
This doctoral thesis deals with the analysis of ultrasound (US) video sequences. It specifically focuses on long-term tracking of the common carotid artery (CCA) in transversal section and measurement of its geometric parameters in a sequence of US images. The design and implementation of a system for automatic tracking of the artery is described in this thesis. The proposed system utilizes Viola-Jones detector and Hough transform to localize the artery in the image. Interest points are detected in the area of the artery wall. These points are then tracked using optical flow. The proposed system comprises a number of innovative methods which allow to perform accurate long-term measurement of parameters of CCA and store the results. A novel mathematical model describing the movement of CCA in transversal section during a cardiac cycle is defined afterwards taking the influence of breathing into consideration. A number of artificial sequences of US images based on this model have been created. These sequences were consequently used to evaluate the accuracy of the proposed system in terms of measuring the parameters of CCA. The sequences are unique because of their length which makes them suitable for evaluation of tracking accuracy even in long video sequences.
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