|
|
Impact of atherosclerotic plaque composition on the development of acute coronary syndrome
Kopřiva, Karel ; Kovárník, Tomáš (advisor) ; Kaňovský, Jan (referee) ; Toušek, Petr (referee)
Thin fibrous cap atheroma with a high lipid content is the most common morphological substrate for acute coronary syndrome. Lipid content can be reliably determined by near infrared spectroscopy (NIRS) imaging. Optical coherence tomography (OCT) is a commonly available morphological imaging method in the guidance of coronary interventions. In our study, we examined a single coronary lesion in patients with acute coronary syndrome using both OCT and NIRS. Based on OCT, we performed a detailed morphological analysis using semi-automated software. Using NIRS, we determined the lipid content of each lesion. In the first part of the study, we used noninvasive CT coronary angiography to detect the progression of atherosclerotic plaques between the first and second year after the initial examination and attempted to demonstrate that morphological characteristics and lipid content of plaques were risk factors for plaque progression. In the second part of the study, we assessed the ability of detailed morphological analysis based on OCT examination to identify the lipid content of plaques using NIRS as a reference method. We observed no significant linear correlation when assessing the relationship between morphological parameters and plaque volume progression. In the analysis of plaque lipid content,...
|
|
|
Analysis of retinal nerve fiber layer for diagnosis of glaucoma
Vodáková, Martina ; Malínský, Miloš (referee) ; Odstrčilík, Jan (advisor)
The master thesis is focused on creating a methodology for quantification of the nerve fiber layer on photographs of the retina. The introductory part of the text presents a medical motivation of the thesis and mentions several studies dealing with this issue. Furthermore, the work describes available textural features and compares their ability to quantify the thickness of the nerve fiber layer. Based on the described knowledge, the methodology to make different regression models enabling prediction of the retinal nerve fiber layer thickness was developed. Then, the methodology was tested on the available image dataset. The results showed, that the outputs of regression models achieve a high correlation between the predicted output and the retinal nerve fiber layer thickness measured by optical coherence tomography. The conclusion discusses an usability of the applied solution.
|
|
|
Perfusion Modelling in Optical Coherence Tomography
Štohanzlová, Petra ; Penhaker,, Marek (referee) ; Kudrna,, Petr (referee) ; Kolář, Radim (advisor)
This thesis deals mainly with perfusion modeling in optical coherence tomography (OCT). The introductory part deals with basic theory of the OCT, including a description of its basic applications. Part of the work was the testing of selected contrasting materials suitable for the OCT and the design and implementation of phantoms, which were subsequently used in the main part of the thesis. In the practical part, attention is paid to the perfusion analysis in the OCT, first the application of the dilution theory in the OCT for flow estimation, then a study testing the basic theory of perfusion on OCT by means of tissue phantom. Another part of the thesis is devoted to the method of speckle variance analysis for flow visualization.
|
|
|
Multimodal retinal image registration
Štohanzlová, Petra ; CSc, Tomáš Suk, (referee) ; Harabiš, Vratislav (advisor)
This work deals with possibilities of registration of retinal images from different mo-dalities, concretely optical coherence tomography (OCT), scanning laser ophthalmoscopy (SLO) and fundus camera. In first stage is the interest focused on registration of SLO and fundus images, which will serve to determine area of interest for consecutive registration of OCT data. The final stage is finding correct location of OCT B-scans in fundus image. On the basis of the studied methods of registration was chosen method making use of computation of correlation coefficient for both cases. For finding optimal parameters of registration is used searching through whole space of parameters. In partial stages of the work was created algorithm for alignment of B-scans followed by detection of blood vessels and also simple algorithm for detection of blood vessels from fundus image. For more transparent registration the graphical user interface was created, which allows loading input images and displaying the result in several possible forms.
|
|
|
Specle analysis for optical coherence tomography image segmentation
Gallo, Vladimír ; Kolář, Radim (referee) ; Štohanzlová, Petra (advisor)
This paper presents basic principles of optical coherence tomography, review of applications and basic categorization of these systems. Paper also deals with the typical properties of images from optical coherence tomography, especially speckle pattern. This paper also provides an overview of the origin of speckle noise and utilization of its dependence on microstructure of probed tissue for image classification based on textural analysis. Experimental part of this paper consists of phantom preparation, data acquisition by OCT system, implementation of speckle analysis in MATLAB and of testing of its functionality on standard textural dataset and also on acquired image phantom data. Speckle analysis is used for phantom image data segmentation.
|
|
|
Segmentation of choroid blood vessels in 3D images from optical coherence tomography
Maňkoš, Richard ; Kolář, Radim (referee) ; Štohanzlová, Petra (advisor)
This project deals with segmentation of choroid blood vessels in 3D images from optical coherence tomography. The first part is dedicated to theoretical description of the human eye. The second part describes basic information about the optical coherence tomography. In the third part two techniques, which are used on the blood vessels segmentation are described. The last part is practical and deals with an image processing in software OCTSEG and with own created algorithm for blood vessel segmentation.
|
|
|
Statistical analysis of images from optical coherence tomography with retinal applications
Kelča, Jan ; Slávik, Vladimír (referee) ; Kolář, Radim (advisor)
This work briefly describes the anatomy of the eye and retinal structure, including its pathological changes. The work is focused on the characteristics and the principle of optical coherence tomography and its application in ophthalmology in conjunction with statistical analysis of retinal images. The practical part explains problems of statistical analysis retinal images using histograms representing the distribution of gray shades and approximation of functions, which are stretched exponential function and Nakagami function. Suitable optimalization are obtained parameters, from which are formed parametric maps illustrating the distribution of gray levels in different areas of interest.
|
|
|
Restoration of optical coherence tomography image data
Smékal, Ondřej ; Odstrčilík, Jan (referee) ; Jan, Jiří (advisor)
Restoration of image data has become an essential part of the processing of medical images obtained by any system. The same applies in the case of optical coherence tomography. The aim of this work is to study the first restoration methods. Second, the description of the data representation from optical coherence tomography and subsequent discussions that restoration methods based on deconvolution would potentially find application in processing of Optical coherence tomography. Finally, the third to create a program solution of the OCT data restoration process in MATLAB environment and followed by discussion of effectiveness of the presented solutions.
|
|
|
Extracting of the optic disc in optical coherence tomography images
Šeda, Jan ; Harabiš, Vratislav (referee) ; Kolář, Radim (advisor)
The main target of this work is a design of the program for border localization of the optic disc in OCT data. Part of this program is also localization of the „optic cup“ and calculation of several values that characterize optic disc. The work is also dealing with a description of the optical coherence tomography principle which is used in ophthalmology. One chapter describes some published methods of optic cup localization. Success of the program and its comparison with OCT Zeiss Stratus 3000 is evaluated at the end of the work.
|
|
|
Extraction of texture features aimed to detect glaucoma defects
Daněk, Daniel ; Kolář, Radim (referee) ; Odstrčilík, Jan (advisor)
The thesis deals with an automatic method of texture analysis using Markov random fields texture modeling. The main aim of this work is to find out relevant textural features, which can be used for appropriate classification of the degree of retinal nerve fiber layer loss. The model of Markovian statistic uses a circular symmetric neighborhood structure and a least square error estimation of the model's parameter. Obtained textural features were quantitatively evaluated using correlation analysis. The results show, that there is a significant correlation between proposed textural features and RNFL thickness measured by OCT. Thus, the features can potentially serve for glaucoma diagnosis.
|
guest ::
