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Acquisition, Modeling and Signal Processing in Ultrasound Perfusion Imaging
Mézl, Martin ; Kozubek, Michal (referee) ; Flusser,, Jan (referee) ; Jiřík, Radovan (advisor)
This work deals with possibilities of ultrasound perfusion analysis for the absolute quantification of perfusion parameters. In the theoretical part of this work are discussed possibilities of using of the ultrasound contrast agents and approaches for the perfusion analysis. New methods for the perfusion analysis are suggested and tested in the practical part of this work. The methods are based on convolutional model in which the concentration of the contrast agent is modeled as aconvolution of the arterial input function and the tissue residual function. The feasibility of these methods for the absolute quantification of perfusion parameters is shown on data from phantom studies, simulations and also preclinical and clinical studies. The software for the whole process of the perfusion analysis was developed for using in hospitals.
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Batch processing of perfusometric MRI data
Filipová, Petra ; Macíček, Ondřej (referee) ; Jiřík, Radovan (advisor)
This diploma thesis deals with the DCE – MRI method (Dynamic contrast enhanced magnetic resonance imaging). Basic principle of magnetic resonance and pulse sequence is described. The diploma thesis focuses on the DCE method, especially on the description of the processing procedure by this method. Description of selected pharmacokinetic models is the part of this diploma thesis as well. Furthermore, description and realization of batch processing by PerfLab system is presented. For verifying purposes of the batch processing functionality real data were measured using created acquisition protocol, which is also part of the diploma thesis.
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Perfusion analysis using DSC-MRI method
Minsterová, Alžběta ; Jiřík, Radovan (referee) ; Macíček, Ondřej (advisor)
This bachelor thesis deals with the DSC (Dynamic Susceptibility Contrast) method, which is one of the magnetic resonance imaging methods using a contrast agent. It describes the principle of the magnetic resonance imaging, other methods of MRI using the contrast agent are mentioned. It further contains the DSC-MRI method, common used sequences and the description of a procedure of an imaging by this method. This thesis also focuses on the implementation of a graphical application in MATLAB, which copes with the perfusion analysis and the visualization of perfusion maps.
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Modelling for ultrasound perfusion imaging
Jakubík, Juraj ; Jiřík, Radovan (referee) ; Mézl, Martin (advisor)
This master thesis deals with the contrast agents and their application in the ultrasound perfusion analysis. It is focused on Bolus & Burst method which, as a combination of two approaches that have been used so far, allows an absolute quantification of perfusion parameters in the region of interest. Contrast agent concentration time sequence is modeled as a convolution of the parametrically defined arterial input function and the tissue residual funkction. Thesis discusses different mathematical models of these functions as well as the methods of the parameters estimation. The methods functionality is validated on simulated and also preclinical data.
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Modelling for ultrasound perfusion imaging
Hracho, Michal ; Šikner, Tomáš (referee) ; Mézl, Martin (advisor)
This thesis deals with the possibilities of determining perfusion parameters of vascular system, using contrast-enhanced ultrasound imaging, which is non-invasive method. Properties of ultrasonography and use of contrast agents are briefly summarized. The methods selected for perfusions analysis were Bolus-tracking¬¬, Burst-replenishment and both of them combined – Bolus&Burst. Parametric models based on these methods were created for modelling an approximation of set perfusion parameters with the use of blind deconvolution.
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Comparison of Pharmacokinetic Models for Quantification of Blood-Brain-Barrier Opening Induced by Focused Ultrasound
Hývlová, Denisa ; Vitouš, Jiří ; Jiřík, Radovan
This paper focuses on quantification of blood-brainbarrier(BBB) opening induced by focused ultrasound. Dynamiccontrast-enhanced MRI (DCE-MRI) with two different pharmacokineticmodels, 2CX and ETK, is used to evaluate BBB opening.The ETK model is commonly used in BBB-opening studies. Wepropose use of a more advanced model, 2CX, that provides moreaccurate estimation of the BBB permeability. The accuracy of themodels is compared using simulated and real data. The resultsdemonstrate similar performance of the 2CX and ETK models inthe brain region with a highly permeable BBB, but the ETK hasproven unable to correctly detect low level of permeabilization.Thus, the 2CX model is more suitable for the studies of BBBpermeabilitydynamics.
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Evolution algorithms for ultrasound perfusion analysis
Kolářová, Jana ; Odstrčilík, Jan (referee) ; Mézl, Martin (advisor)
This master´s thesis is focused on the application of evolutionary algorithms for interleaving data obtained by ultrasound scanning of tissue. The interleaved curve serves to estimate perfusion parameters, thus allowing to detect possible pathophysiology in the scanned area. The theoretical introduction is devoted to perfusion and its parameters, contrast agents for ultrasonic application, ultrasonic modality scanning, optimization, evolutionary algorithms in general and two selected evolutionary algorithms - genetic algorithm and bee algorithm. These algorithms were tested on noisy data obtained from clinical images of mice with tumor. The final part summarizes the results of the practical part and provides suggestions and recommendations for further possible development.
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Comparison of Pharmacokinetic models for DCE-MRI
Bačovská, Kristýna ; Mézl, Martin (referee) ; Jiřík, Radovan (advisor)
This thesis deals with perfusion analysis using DCE-MRI (Dynamic contrast-enhanced magnetic resonance imaging). DCE-MRI is commonly used for microcirculation evaluation mainly in oncology and in recent years also in cardiology. The theoretical overview focuses on the issue of pharmacokinetic modeling and the estimation of perfusion parameters using selected models. The experimental part describes research software PerfLab and then it is aimed at the proposed program for synthetic data generation. Simulated data obtained under ideal conditions and in the presence of noise were used to compare models for the accuracy and reliability of DCE-MRI analysis.
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Simulation of ultrasound sequences in contrast mode
Staňková, Jana ; Mézl, Martin (referee) ; Harabiš, Vratislav (advisor)
This bachelor thesis deals with the principle of contrast imaging techniques for ultrasound imaging. In the first part there are described basic principles and characteristics of ultrasound waves for the understanding. It is also focused on ultrasound contrast agents used in contrast enhanced ultrasound imaging. The important part is the description of perfusion models with a focus on obtaining perfusion parametres and analyzing perfusion curves obtained by measuring the ultrasound contrast agent over time. The second part is devoted to designing a program for generating simulated ultrasound images and description of the simulation of 2D ultrasound tomograms.
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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.
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