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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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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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Doppler blood flow indicator
Böhm, Richard ; Bubník, Karel (referee) ; Rozman, Jiří (advisor)
This bachelor‘s thesis deals with literature search of basis of ultrasonic and Doppler methods of measuring blood flow velocity. It also deals with the evaluation of Doppler signals and with the individual functional system blocks, with the indicator of blood flow with the operating frequency of 4 MHz, with the generated ultrasonic intensity of 100 mW/cm2 and with the average transmitting changer in shape of D = 8 mm. Furthermore, experimental verification of individual system components is included.
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Ultrasound fetal detector
Mackových, Marek ; Čech, Petr (referee) ; Rozman, Jiří (advisor)
This work deals with the design of simple fetal detector, which can obtain information about fetal heart rate during pregnancy. The work includes theoretical description of Doppler systems and custom systems design detector.
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Ultrasound blood flow detector
Vožda, Michal ; Dlouhý, Jiří (referee) ; Rozman, Jiří (advisor)
This work deals with Doppler methods of measuring blood flow in blood vessels and a simple design with a continuous wave for the 4 MHz frequency and intensity of ultrasound 100 mW/cm2. The work contains a description of the functional blocks and design of their involvement. Individual blocks are simulated in PSpice. The resulting circuit is a printed circuit board and a 3D model of the plate fitted in EAGLE.
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Ultrasound blood flow detector
Šimák, Jakub ; Dlouhý, Jiří (referee) ; Rozman, Jiří (advisor)
Bachelor's thesis deals with design and electrical scheme of simple ultrasonic blood flow indicator, by which is possible get information of speed of blood without any invasion into patient's body. This device has been proposed for measure speed of blood in lower limbs, mainly patients with ischemic disease.
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Ultrasound blood flowmeter for haemodialysis monitor
Krohová, Lucie ; Sekora, Jiří (referee) ; Rozman, Jiří (advisor)
The main objective of this thesis is to get know about introduce the principles of hemodialysis, blood flow measurement methods and the creation the system and peripheral design of blood flow meter. The thesis contains an introduction to hemodialysis, a description of the dialysis monitor, the distribution of ultrasonic flow meters and system design of blood flow meter with a brief description of each function block, circuit diagram of a flow meter and experimental verification of the circuit. There are also the list of components, printed circuit board drawing and technical drawing of the sensor included.
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Ultrasound blood flow detector
Kameníček, Robert ; Dlouhý, Jiří (referee) ; Rozman, Jiří (advisor)
My master’s thesis deals with methods of measuring the ultrasonic blood flow blood vessel with a detailed focus on Doppler ultrasound systems, which find application in the diagnosis of superficial vascular and obstetrics. The thesis is described a proposal indicating polydirectional Doppler system with a continuous carrier wave frequency of 4 MHz, the intensity of ultrasound 100 mW/cm2 and diameter D-shaped transducers 8 mm. As a result, the indicator will be able to measure blood flow velocity in the range of 5-40 cm/s, which appears to 3.5 digit display. After describing important theoretical assumptions, the work pays block diagram indicator. Furthermore, it examines the various functional blocks on the requirements imposed on them. It looks at the options of each functional block, and finally describes the implementation of the selected option and including peripheral solutions. Great attention is paid to the power of the indicator, where the power supply will be used 9 V battery. Create a symmetric voltage for operate amplifier and other auxiliary voltage will procure DC/DC converters. In conclusion, the work is located around the perimeter solutions indicator. The following draft for the production of double-sided PCB, its installation and a list of elements. The outcome of the thesis is complete documentation for the implementation of an indicator of blood flow, which allows us to obtain information on throughput vessels, especially the lower and upper limbs.
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Doppler measurement of vessel parameters
NÁTHEROVÁ, Markéta
Ultrasound investigation is the most common and most readily available current advanced diagnostic method. Ultrasound can be used to track and image moving structures such as cardiac valves or flowing blood {--} these methods are based on the so-called Doppler phenomenon. Using the Doppler phenomenon, it is possible to determine the velocity and direction of movement of the measured object. The objective of this work was to track the changes of vascular flow and pulse rate depending on the degree of tolerance of exercise attained by the test persons, the stress (load) and ambient temperature changes. For this purpose, 2 groups were defined where the first group consisted of individuals adapted to the stress, while the members of the second group were untrained. To measure the vascular parameters we used a Doppler meter, HiDop 300. The LCD display of the instrument, or alternatively the monitor of a connected computer, provide images of the measured spectral Doppler curve as well as its parameters (heart rate HR, resistance index RI, pulsatility index PI, systolic/diastolic ratio, mean frequency). The work is concerned with the impact of physical load and cold-related stress on the circulatory system in the vessels. The haemodynamics of the vascular system depends on the type and intensity of the load. The formulation of results of the work, however, must account for a number of internal factors (age, sex, health {\dots}) and external factors (ambient temperature, air flow {\dots}) that are themselves associated with various changes in the circulatory system. For example, reduction of peripheral vascular contractility in the elderly, disruption of vascular wall elasticity by depositing fatty substances or increased heart rate due to the stress stimulus. The main advantage of a Doppler instrument and all ultrasound methods is to be seen in the fact that it is a non-invasive method, and has no adverse effects on the investigated person, such as the effects associated with roentgen radiation, provided, however, that appropriate intensity of ultrasound radiation has been chosen.
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Baroreflex sensitivity and heart rate
Halámek, Josef ; Jurák, Pavel ; Swenne, C. A. ; Kára, T. ; Souček, M. ; Eisenberg, M. ; Nykodým, J.
The correlation between baroreflex sensitivity (BRS) and heart rate (HR) is discussed. According to theoretical model, where the constant blood flow is supposed, the BRS given in [ms/mmHg] must correlate with HR and BRS in [mHz/mmHg] should not correlate with HR. This assumption was confirmed by the measurement on healthy young subjects, but it is not valid for old healthy subjects and for patients.
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