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Methods of weighting the magnetic resonance signal
Filla, David ; Kubásek, Radek (referee) ; Hadinec, Michal (advisor)
The objective of this project is introduction to the fundamental principle of magnetic resonance and to the basic measuring methods used in MR. There is also described how to set parameters of pulse sequences in different measuring methods to obtain an image weighted by relaxation T1, relaxation T2, diffusion and eventually proton density. In the experimental part, we have measured images of three samples (tomato, pepper and mandarin) by four methods (SE, GE, IRSE and IRFSE). For obtained measured images we have proceed phase correction, created T2 and T2* maps. Then we consider the images obtained in terms of quality and compare with each other.
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Quantification of T1 for Preclinical MRI
Dvořáková, Lenka ; Macíček, Ondřej (referee) ; Jiřík, Radovan (advisor)
T1 mapping of myocardial tissue is important for diagnostics of myocardial fibrosis. Cardiac magnetic resonance imaging of small animals is challenging due to high heart and respiratory rates. Pulse sequences for T1 mapping are proposed in this thesis based on inversion recovery FLASH and Intragate FLASH. The sequence IR FLASH was compared to the reference sequence RARE on a static phantom. Both sequences were applied for measuring the myocardium of a rat. For T1 quantification a software in Matlab was developed. Using this software, T1 maps of rat myocardium were calculated.
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Analysys of magnetic field homogenity at computer tomography
Hrach, Petr ; Drexler, Petr (referee) ; Hadinec, Michal (advisor)
The dissertation deals with nuclear magnetic resonance, its projection technologies, measurement of magnetic induction and evaluation of magnetic field homogenity by the help of measuring probe. Further, the methods of NMR measurements are being described. The dissertation concentrates on methods of spin and gradient echo. The experimental part describes measurement of magnetic field homogenity in tomography and subsequent projection of measured field map. Users application, created in terms of dissertation, has more save labour imagery magnetic fields.
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Contrast enhancement for tissue discrimination and contrast nanoparticle detection by MRI
Bačovský, Jaromír ; Macíček, Ondřej (referee) ; Starčuk, Zenon (advisor)
Magnetic resonance imaging is a routine and powerful diagnostic technique capable of providing detailed information about the structure and composition of the tissues. This diploma thesis is concerned with the mechanisms of contrast origin and contrast modifications by molecular and nanoparticle contrast agents. First sections of the thesis summarize basic knowledge about pulse sequences and it aims to provide an overview on MRI contrast agent with a special emphasis on paramagnetic gadolinium contrast agents and superparamagnetic nanoparticles. The main purpose of this study is to develop the software called MRICalc, which is able to optimize contrast in MRI images. Based on analysis of signal formula of typical pulse sequences, MRICalc is able to propose the parameters of the pulse sequence for compartment-specific enhancement of the contrast. User chooses from the list of the samples and after calculation he obtains the values of echo time, repetition time and flip angle, all of which simultaneously seem to create the appropriate setting to enhance the contrast. MRICalc also allows to plot contrast function with respect to the chosen parameter. Software, including its graphical user interface, is designed in Python. The sample consists from solution of CuSO4 and distilled water was designed to verify the correct function of MRICalc. Sulphate represents a contrast agent. Preclinical MR system Bruker BioSpec 94/30 USR located at Institute of Scientific Instruments of the ASCR, v.v.i was used to measure contrast curve of FLASH pulse sequence, which is a typical representative of gradient echo. Results of the measurement were compared to the theoretical model provided by MRICalc.
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Contrast enhancement for tissue discrimination and contrast nanoparticle detection by MRI
Bačovský, Jaromír ; Macíček, Ondřej (referee) ; Starčuk, Zenon (advisor)
Magnetic resonance imaging is a routine and powerful diagnostic technique capable of providing detailed information about the structure and composition of the tissues. This diploma thesis is concerned with the mechanisms of contrast origin and contrast modifications by molecular and nanoparticle contrast agents. First sections of the thesis summarize basic knowledge about pulse sequences and it aims to provide an overview on MRI contrast agent with a special emphasis on paramagnetic gadolinium contrast agents and superparamagnetic nanoparticles. The main purpose of this study is to develop the software called MRICalc, which is able to optimize contrast in MRI images. Based on analysis of signal formula of typical pulse sequences, MRICalc is able to propose the parameters of the pulse sequence for compartment-specific enhancement of the contrast. User chooses from the list of the samples and after calculation he obtains the values of echo time, repetition time and flip angle, all of which simultaneously seem to create the appropriate setting to enhance the contrast. MRICalc also allows to plot contrast function with respect to the chosen parameter. Software, including its graphical user interface, is designed in Python. The sample consists from solution of CuSO4 and distilled water was designed to verify the correct function of MRICalc. Sulphate represents a contrast agent. Preclinical MR system Bruker BioSpec 94/30 USR located at Institute of Scientific Instruments of the ASCR, v.v.i was used to measure contrast curve of FLASH pulse sequence, which is a typical representative of gradient echo. Results of the measurement were compared to the theoretical model provided by MRICalc.
|
|
|
Analysys of magnetic field homogenity at computer tomography
Hrach, Petr ; Drexler, Petr (referee) ; Hadinec, Michal (advisor)
The dissertation deals with nuclear magnetic resonance, its projection technologies, measurement of magnetic induction and evaluation of magnetic field homogenity by the help of measuring probe. Further, the methods of NMR measurements are being described. The dissertation concentrates on methods of spin and gradient echo. The experimental part describes measurement of magnetic field homogenity in tomography and subsequent projection of measured field map. Users application, created in terms of dissertation, has more save labour imagery magnetic fields.
|
|
|
Methods of weighting the magnetic resonance signal
Filla, David ; Kubásek, Radek (referee) ; Hadinec, Michal (advisor)
The objective of this project is introduction to the fundamental principle of magnetic resonance and to the basic measuring methods used in MR. There is also described how to set parameters of pulse sequences in different measuring methods to obtain an image weighted by relaxation T1, relaxation T2, diffusion and eventually proton density. In the experimental part, we have measured images of three samples (tomato, pepper and mandarin) by four methods (SE, GE, IRSE and IRFSE). For obtained measured images we have proceed phase correction, created T2 and T2* maps. Then we consider the images obtained in terms of quality and compare with each other.
|
|
|
Quantification of T1 for Preclinical MRI
Dvořáková, Lenka ; Macíček, Ondřej (referee) ; Jiřík, Radovan (advisor)
T1 mapping of myocardial tissue is important for diagnostics of myocardial fibrosis. Cardiac magnetic resonance imaging of small animals is challenging due to high heart and respiratory rates. Pulse sequences for T1 mapping are proposed in this thesis based on inversion recovery FLASH and Intragate FLASH. The sequence IR FLASH was compared to the reference sequence RARE on a static phantom. Both sequences were applied for measuring the myocardium of a rat. For T1 quantification a software in Matlab was developed. Using this software, T1 maps of rat myocardium were calculated.
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