The thesis deals with measurements of the atherosclerothic carotid plaques mechanical properties with wiew towards the improvements of their constitutive models and then towards the impact of application of those constitutive models in fibrous cap. The introductory part provides a brief summary of medical knowledge needed to understand atheroma formation and the risks involved. Next, there's a survey of plaque mechanical testing methods and the obtained results on tissue properties. The previously used constitutive models of atherosclerothic tissues are listed as well. Main body of the thesis describes the preparation of testing samples from obtained atheroma, methodology and course of experiments execution and subsequent processing of the experimental data to evaluate the behavior of the atheromatous tissue individual parts. Then the discussion and evaluation of our results and findings is given. Along with the evaluated mechanical properties, experimental data fitted to models are presented with respect to their predictive abilities. The final part is dedvoted to the finite element analysis of an idealized 2D model with emphasis on the effect of necrotic core and fibrous tissue properties on von Mises equivalent stress in the fibrous cap.

This master's thesis deals with pulsating flow of Newtonian and non-Newtonian fluid. Theoretical part represents necessary theoretical knowledge for pulsating flow and understanding of non-Newtonian behaviour. Furthermore the thesis focus is directed on numerical simulation of pulsating flow in straight, ideally rigid tube and in patient-specific model of human artery, more precisely in carotid. Two methods are used: numerical solution based on finite volume method (FVM) and also analytical solution using Bessel functions by Womersley. Results are validated against experimental measurements of velocity profiles by particle image velocity method (PIV). The agreement between numerical and experimental data with consideration of PIV inaccuracy was was very good from both point of views - qualitative and quantitative. Numerical solution also compare influence of turbulence and non-Newtonian behaviour towards base (laminar flow, Newtonian fluid). Developed methodology is then applied on patient-specific model of carotid, which was renovated from computed tomography. Measurements in vivo in human arteries is very expensive and often invasive. Because of that measurement outputs are limited, most of the time on pressure and flow. Computational fluid dynamics (CFD) is non-invasive and outputs are through whole domain. Due to these advantages CFD significantly contributes to understanding of hemodynamics influence in cardiovascular diseases.

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.

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.