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Measurement of relaxation constants by use of magnetic resonance
Kořínek, Radim ; Bartušek, Karel (referee) ; Gescheidtová, Eva (advisor)
This bachelor’s thesis is dedicated to principles of magnetic resonance and measurement of relaxation times. At theoretical part all basics methods of measurement (SE-spin echo, GE-gradient echo, SR-saturation recovery, IR- inversion recovery) of relaxation times T1, T2 resp. T2* are shown. At practical part T1 and flip angles are carefully observed. In case of measurement of relaxation time T2, the FID signal acquisition after 90° RF pulse is sufficient. T2* time is set from absorbtion line. For measurement of transversal relaxation method SE (often called as Hahn spin echo –90° RF pulse is followed by next 180° RF pulse) can be used. With GE method, the T2* relaxation is observed. Measurement of relaxation time T1 using RF impulses and inclinable angles A, is described at chapter 3. Every magnetization components during RF impulses are deeply described by mathematical formulas. Other chapter of this bachelor thesis describes some functions from MATLAB and their fitness for approximation of signal. From every tested functions, the lsqcurvefit function would be the best. Iteration method is most fitting function for approximation of FID signal.
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Errors of diffusion measurements for MRI
Kavan, Pavel ; Rampl, Ivan (referee) ; Bartušek, Karel (advisor)
The Bachelor’s thesis is, at it’s begining, focused on the imaging and diagnostic techniques based on principles of magnetic resonance imaging. Nowadays, nuclear magnetic resonance belongs to reputable examing methods of variable molecule matters. Especially, due to multiinterval spin-echo PFGSE methods. Further in this thesis is spin-echo pulse sequence simulated in the data processing computer program Matlab. Simulations influencing error measurement of b-factor and diffusion are performed. These simulations could help to prevent appearance of measurement errors at some other experiments.
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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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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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Relaxation times in the polymer gel electrolytes by magnetic resonance methods
Jehličková, Lenka ; Kadlec, Radim (referee) ; Kubásek, Radek (advisor)
The purpose of this Bachelor’s thesis is measuring of gelly structure relaxation using magnetic resonance imaging. The first part closely describes the theory needed for upcoming measuring. There is explained basic physical principle of NMR and terms such as precession, Larmor frequency and RF pulses are established. The measuring instrument is also schematically introduced, as are its main parts and division in aspect of magnetic fields. The most important part is explanation and understanding of relaxation processes that happen during NMR. Individual sequences used for measuring of relaxation processes are demonstrated by the spin echo method, which is the basic building block of all successive methods. The second part is processing of results. Measuring of fall and spectre of given gelly samples is expressed as a function of time T2 on the sample solidification time.
|
|
|
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.
|
|
|
Errors of diffusion measurements for MRI
Kavan, Pavel ; Rampl, Ivan (referee) ; Bartušek, Karel (advisor)
The Bachelor’s thesis is, at it’s begining, focused on the imaging and diagnostic techniques based on principles of magnetic resonance imaging. Nowadays, nuclear magnetic resonance belongs to reputable examing methods of variable molecule matters. Especially, due to multiinterval spin-echo PFGSE methods. Further in this thesis is spin-echo pulse sequence simulated in the data processing computer program Matlab. Simulations influencing error measurement of b-factor and diffusion are performed. These simulations could help to prevent appearance of measurement errors at some other experiments.
|
|
|
Relaxation times in the polymer gel electrolytes by magnetic resonance methods
Jehličková, Lenka ; Kadlec, Radim (referee) ; Kubásek, Radek (advisor)
The purpose of this Bachelor’s thesis is measuring of gelly structure relaxation using magnetic resonance imaging. The first part closely describes the theory needed for upcoming measuring. There is explained basic physical principle of NMR and terms such as precession, Larmor frequency and RF pulses are established. The measuring instrument is also schematically introduced, as are its main parts and division in aspect of magnetic fields. The most important part is explanation and understanding of relaxation processes that happen during NMR. Individual sequences used for measuring of relaxation processes are demonstrated by the spin echo method, which is the basic building block of all successive methods. The second part is processing of results. Measuring of fall and spectre of given gelly samples is expressed as a function of time T2 on the sample solidification time.
|
|
|
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.
|
|
|
Measurement of relaxation constants by use of magnetic resonance
Kořínek, Radim ; Bartušek, Karel (referee) ; Gescheidtová, Eva (advisor)
This bachelor’s thesis is dedicated to principles of magnetic resonance and measurement of relaxation times. At theoretical part all basics methods of measurement (SE-spin echo, GE-gradient echo, SR-saturation recovery, IR- inversion recovery) of relaxation times T1, T2 resp. T2* are shown. At practical part T1 and flip angles are carefully observed. In case of measurement of relaxation time T2, the FID signal acquisition after 90° RF pulse is sufficient. T2* time is set from absorbtion line. For measurement of transversal relaxation method SE (often called as Hahn spin echo –90° RF pulse is followed by next 180° RF pulse) can be used. With GE method, the T2* relaxation is observed. Measurement of relaxation time T1 using RF impulses and inclinable angles A, is described at chapter 3. Every magnetization components during RF impulses are deeply described by mathematical formulas. Other chapter of this bachelor thesis describes some functions from MATLAB and their fitness for approximation of signal. From every tested functions, the lsqcurvefit function would be the best. Iteration method is most fitting function for approximation of FID signal.
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