|
|
Increasing Resolution in Perfusion Magnetic Resonance Imaging Using Compressed Sensing
Mangová, Marie ; Polec,, Jaroslav (referee) ; Šmídl, Václav (referee) ; Rajmic, Pavel (advisor)
Perfusion magnetic resonance imaging is a medical diagnostic method which requires high spatial and temporal resolution simultaneously to capture dynamics of an intravenous contrast agent which is used to perfusion measurement. However, magnetic resonance imaging has physical limits which do not allow to have this resolution simultaneously. This thesis deals with compressed sensing which enables to reconstruct measured data from relatively few acquired samples (below Nyquist rate) while resolution required to perfusion analysis is increased. This aim could be achieved with suitably proposed apriory information about sensed data and model proposal. The reconstruction is then done as an optimization problem. Doctoral thesis brings several new reconstruction models, further proposes method to debias this estimates and examines influence of compressed sensing onto perfusion parameters. Whole thesis is ended with extension of compressed sensing into three-dimensional data. Here, the influence of reconstruction onto perfusion parameters is also described. In summary, the thesis shows that due to compressed sensing, temporal resolution can be increased with the fixed spatial resolution or spatial resolution can be increased with the fixed temporal resolution.
|
|
|
Modelling in perfusion MR imaging
Válková, Hana ; Jiřík, Radovan (referee) ; Kratochvíla, Jiří (advisor)
This thesis deals with the magnetic resonance perfusion data analysis especially DCEMRI. In its introduction the thesis describes the problem of DCE-MRI data aquisition, the necessity of appropriate contrast agent and basic principles of perfusion analysis. The dynamic behavior of contrast agent vascular distribution can be described by arterial input function (AIF). The shape of the curves close to the area of interest is affected by dispersion which is called vascular transport function (VTF) due to the distribution of the contrast agent to the region of interest. Finally the tissue residual function describes system behavior of tissue. The practical part of the diploma thesis is aimed at implementation of model curves AIF, VTF and TRF. Furthermore, a simulation program was created for easy manipulation with introduced models moreover the program is used to perform an estimation of perfusion parameters based on nonblind deconvolution. The method is validated on synthetic data and illustrated on clinical data of the renal cell carcinoma patient.
|
|
|
Compressed sensing in magnetic resonance perfusion imaging.
Mangová, Marie ; Veselý, Vítězslav (referee) ; Rajmic, Pavel (advisor)
Magnetic resonance perfusion imaging is a today's very promising method for medicine diagnosis. This thesis deals with a sparse representation of signals, low-rank matrix recovery and compressed sensing, which allows overcoming present physical limitations of magnetic resonance perfusion imaging. Several models for reconstruction of measured perfusion data is introduced and numerical methods for their software implementation, which is an important part of the thesis, is mentioned. Proposed models are verified on simulated and real perfusion data from magnetic resonance.
|
|
|
Arterial Spin Labeling MRI Data Analyzation
Galanová, Zuzana ; Jiřík, Radovan (referee) ; Krátká, Lucie (advisor)
This bachelor´s thesis is focusing mostly on perfusion imagining, which is done by the method of arterial spin labeling. It describes physical basics of nuclear magnetic resonance, image reconstruction, perfusion imagining without contrast substances, principles of arterial spin labeling and different ways of arterial spin labeling – mostly FAIR-RARE sequence, which belongs to the pulsed arterial spin labeling. One part of the thesis is dedicated to production of perfusion map in Matlab. Results are evaluated by comparison of data produced in Matlab and data produced in Paravision Version 5.1 and they are discussed.
|
|
|
Image segmentation of ultrasound images
Schwarzerová, Jana ; Odstrčilík, Jan (referee) ; Mézl, Martin (advisor)
This bachelor’s thesis deals with basic description of ultrasonography, principles of contrast-enhanced imaging and application of segmentation methods in ultrasound problematics. Some individual methods were implemented in Matlab, version R2015b. Algorithms were tested on synthetic images data, on ultrasound phantom images data and on real ultrasound images. Then the thesis was extended by ultrasound sequences segmentation.
|
|
|
Simulation of pharmacokinetic models
Hejč, Jakub ; Jiřík, Radovan (referee) ; Mézl, Martin (advisor)
The theoretical part of this project is occupied with analysis of pharmacokinetic actions and also basic attributes of mathematical models used in pharmacokinetics. This description is mainly focused on models used for perfusion imaging methods. The aim of this project is to create an algorithm that simulates chosen models based on assigned parameters and also an algorithm that serves to fit experimentally measured data with a chosen model with a calculation of basic pharmacokinetic parameters. The next step of this solution is graphic interface realization which enables a full use of created algorithm in more accessible surroundings for the user. The result of this work is a program that can be used to obtain real data parameters and as well as a visual sample of the influence of these parameters on a process in a chosen functions.
|
|
|
Contrast MRI perfusion imaging
Šejnoha, Radim ; Harabiš, Vratislav (referee) ; Krátká, Lucie (advisor)
This semestral thesis is focused on contrast MRI perfusion imaging using method of Dynamic Contrast-Enhanced MRI. It describes basic principles of nuclear magnetic resonance and puls sequences used in DCE MRI. The thesis contains a part dedicated to dynamic contrast imaging of phantom with experimental NMR device located at the Institut of Scientific Instruments of the ASCR in Brno. Results of measurements are analyzed based on models and reached perfusion parameters are discussed.
|
|
|
Image registration using evolutionary algorithms
Kubalová, Eva ; Kozumplík, Jiří (referee) ; Mézl, Martin (advisor)
The diploma thesis deals with the image registration using evolutionary algorithms from metaheuristic optimization techniques which are considered recent and widely used. The frst part of the thesis contains theoretical description of components in image registration and later focuses on the ultrasound images. In that part, the thesis explains chosen evolutionary algorithms. Three optimization methods have been implemented, in particular genetic algorithm, particle swarm optimization and frey algorithm. Chosen similarity metrics for optimization are sum of squared dierences, cosine similarity and correlation coefcient. The main part of thesis includes testing of proposed methods with the evaluation of obtained results. These parameters are later used for optimization of real ultrasound sequences obtained by the contrast imaging.
|
|
|
Graphical user interface for magnetic resonance data reconstruction
Marcin, Michal ; Rajmic, Pavel (referee) ; Mangová, Marie (advisor)
The aim of the bachelor thesis was to create graphical user interface for processing magnetic resonance data. For this purpose, the Matlab development environment was used. The basic principles of magnetic resonance, the ways of scanning and the graphical imaging as well as mathematical methods are described in the first part. The method of compression scanning and imaging of real images using laboratory mice is described in the text. In the second part of the thesis, the graphical user environment and its functions are described. The program is able to simulate and display the Shepp-Logan phantom model according to specified parameters. The created application allows the reconstruction and processing of simulated as well as real data.
|
|
|
Deconvolution in perfusion imaging
Líbal, Marek ; Havlíček, Martin (referee) ; Bartoš, Michal (advisor)
The purpose of this study is to introduce the methods of the deconvolution and to programme some of them. For the simulation, the tissue homogeneity model and the model of arterial input fiction were used. These models were engaged as the test procedures with the aim of verify the functionality and utility of the Wiener filter, the Lucy-Richardson algorithm and the Singular value decomposition.
|
guest ::
