Dissertations / Theses on the topic 'Ultrasound Pulse Wave'

Thesis (M.Eng. and S.B.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.
Includes bibliographical references (p. 77-79).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cardiovascular disease is the leading cause of death in many developed countries. Arteries of people suffering from this disease become stiff and blocked by fatty deposits. In recent years, non-invasive imaging techniques have been playing an increasingly important role in detecting the development of cardiovascular disease. Several methods focus on the measurement of pulse wave velocity, the velocity at which the pressure wave propagates, because it is directly related to arterial stiffness. The objective of this project is to investigate the feasibility of measuring local pulse wave velocity from the blood flow waveforms acquired by Doppler ultrasound. The proposed method includes the following steps: first acquire flow waveforms by Doppler ultrasound at two locations within the same artery, next detect the delay or difference in arrival time of the flow wave at the two arterial locations, and then calculate the PWV by dividing the length of the arterial segment being imaged by the calculated time delay. Although at the conclusion of this study reliable pulse wave velocity detection is not achieved, the study sheds light on many important issues surrounding this potential application. The project explores how sources of variations such as radial positioning of the probe and noise level affect the accuracy of the delay estimate.
by Minnan Xu.
M.Eng.and S.B.

This thesis presents the investigations conducted in the use of ultrasonic technology to measure two-phase flow in both horizontal and vertical pipe flows which is important for the petroleum industry. However, there are still key challenges to measure parameters of the multiphase flow accurately. Four methods of ultrasonic technologies were explored. The Hilbert-Huang transform (HHT) was first applied to the ultrasound signals of air-water flow on horizontal flow for measurement of the parameters of the two- phase slug flow. The use of the HHT technique is sensitive enough to detect the hydrodynamics of the slug flow. The results of the experiments are compared with correlations in the literature and are in good agreement. Next, experimental data of air-water two-phase flow under slug, elongated bubble, stratified-wavy and stratified flow regimes were used to develop an objective flow regime classification of two-phase flow using the ultrasonic Doppler sensor and artificial neural network (ANN). The classifications using the power spectral density (PSD) and discrete wavelet transform (DWT) features have accuracies of 87% and 95.6% respectively. This is considerably more promising as it uses non-invasive and non-radioactive sensors. Moreover, ultrasonic pulse wave transducers with centre frequencies of 1MHz and 7.5MHz were used to measure two-phase flow both in horizontal and vertical flow pipes. The liquid level measurement was compared with the conductivity probes technique and agreed qualitatively. However, in the vertical with a gas volume fraction (GVF) higher than 20%, the ultrasound signals were attenuated. Furthermore, gas-liquid and oil-water two-phase flow rates in a vertical upward flow were measured using a combination of an ultrasound Doppler sensor and gamma densitometer. The results showed that the flow gas and liquid flow rates measured are within ±10% for low void fraction tests, water-cut measurements are within ±10%, densities within ±5%, and void fractions within ±10%. These findings are good results for a relatively fast flowing multiphase flow.

Cardiovascular diseases are the leading causes of death worldwide and improved diagnostic methods are needed for early intervention and to select the most suitable treatment for patients. Currently, carotid artery plaque vulnerability is typically determined by visually assessing ultrasound B-mode images, which is influenced by user-subjectivity. Since plaque vulnerability is correlated to the mechanical properties of the plaque, quantitative techniques are needed to estimate plaque stiffness as a surrogate for plaque vulnerability, which would reduce subjectivity during plaque assessment. The work in this thesis focused on three noninvasive ultrasound-based techniques to quantitatively assess plaque vulnerability and measure arterial stiffness. In Study I, a speckle tracking algorithm was validated in vitro to assess strain in common carotid artery (CCA) phantom plaques and thereafter applied in vivo to carotid atherosclerotic plaques where the strain results were compared to visual assessments by experienced physicians. In Study II, hard and soft CCA phantom plaques were characterized with shear wave elastography (SWE) by using phase and group velocity analysis while being hydrostatically pressurized followed by validating the results with mechanical tensile testing. In Study III, feasibility of assessing the stiffness of simulated plaques and the arterial wall with SWE was demonstrated in an ex vivo setup in small porcine aortas used as a human CCA model. In Study IV, SWE and pulse wave imaging (PWI) were compared when characterizing homogeneous CCA soft phantom plaques. The techniques developed in this thesis have demonstrated potential to characterize carotid artery plaques. The results show that the techniques have the ability to noninvasively evaluate the mechanical properties of carotid artery plaques, provide additional data when visually assessing B-mode images, and potentially provide improved diagnoses for patients suffering from cerebrovascular diseases.

Doctoral thesis in medical technology and medical sciences

QC 20160921

This Mater's thesis deals with the evaluation of pulse wave velocity using multi-channel whole-body impedance cardiography. Data were taken from the group of healthy volunteers whose impedance changes were measured during rest, respiratory maneuvers, tilt and stress exercise. The result of this measurement are values of peaks of pulse wave time shifts towards R-wave. The velocity values towards the thorax electrodes were recalculated on the basis of knowledge about the pulse wave time shifts and the distances from the heart to the scanned locations, which were measured using the arterial segment's lengths.

The ability of a piezoelectric transducer in energy conversion is rapidly expanding in several applications. Some of the industrial applications for which a high power ultrasound transducer can be used are surface cleaning, water treatment, plastic welding and food sterilization. Also, a high power ultrasound transducer plays a great role in biomedical applications such as diagnostic and therapeutic applications. An ultrasound transducer is usually applied to convert electrical energy to mechanical energy and vice versa. In some high power ultrasound system, ultrasound transducers are applied as a transmitter, as a receiver or both. As a transmitter, it converts electrical energy to mechanical energy while a receiver converts mechanical energy to electrical energy as a sensor for control system. Once a piezoelectric transducer is excited by electrical signal, piezoelectric material starts to vibrate and generates ultrasound waves. A portion of the ultrasound waves which passes through the medium will be sensed by the receiver and converted to electrical energy. To drive an ultrasound transducer, an excitation signal should be properly designed otherwise undesired signal (low quality) can deteriorate the performance of the transducer (energy conversion) and increase power consumption in the system. For instance, some portion of generated power may be delivered in unwanted frequency which is not acceptable for some applications especially for biomedical applications. To achieve better performance of the transducer, along with the quality of the excitation signal, the characteristics of the high power ultrasound transducer should be taken into consideration as well. In this regard, several simulation and experimental tests are carried out in this research to model high power ultrasound transducers and systems. During these experiments, high power ultrasound transducers are excited by several excitation signals with different amplitudes and frequencies, using a network analyser, a signal generator, a high power amplifier and a multilevel converter. Also, to analyse the behaviour of the ultrasound system, the voltage ratio of the system is measured in different tests. The voltage across transmitter is measured as an input voltage then divided by the output voltage which is measured across receiver. The results of the transducer characteristics and the ultrasound system behaviour are discussed in chapter 4 and 5 of this thesis. Each piezoelectric transducer has several resonance frequencies in which its impedance has lower magnitude as compared to non-resonance frequencies. Among these resonance frequencies, just at one of those frequencies, the magnitude of the impedance is minimum. This resonance frequency is known as the main resonance frequency of the transducer. To attain higher efficiency and deliver more power to the ultrasound system, the transducer is usually excited at the main resonance frequency. Therefore, it is important to find out this frequency and other resonance frequencies. Hereof, a frequency detection method is proposed in this research which is discussed in chapter 2. An extended electrical model of the ultrasound transducer with multiple resonance frequencies consists of several RLC legs in parallel with a capacitor. Each RLC leg represents one of the resonance frequencies of the ultrasound transducer. At resonance frequency the inductor reactance and capacitor reactance cancel out each other and the resistor of this leg represents power conversion of the system at that frequency. This concept is shown in simulation and test results presented in chapter 4. To excite a high power ultrasound transducer, a high power signal is required. Multilevel converters are usually applied to generate a high power signal but the drawback of this signal is low quality in comparison with a sinusoidal signal. In some applications like ultrasound, it is extensively important to generate a high quality signal. Several control and modulation techniques are introduced in different papers to control the output voltage of the multilevel converters. One of those techniques is harmonic elimination technique. In this technique, switching angles are chosen in such way to reduce harmonic contents in the output side. It is undeniable that increasing the number of the switching angles results in more harmonic reduction. But to have more switching angles, more output voltage levels are required which increase the number of components and cost of the converter. To improve the quality of the output voltage signal with no more components, a new harmonic elimination technique is proposed in this research. Based on this new technique, more variables (DC voltage levels and switching angles) are chosen to eliminate more low order harmonics compared to conventional harmonic elimination techniques. In conventional harmonic elimination method, DC voltage levels are same and only switching angles are calculated to eliminate harmonics. Therefore, the number of eliminated harmonic is limited by the number of switching cycles. In the proposed modulation technique, the switching angles and the DC voltage levels are calculated off-line to eliminate more harmonics. Therefore, the DC voltage levels are not equal and should be regulated. To achieve this aim, a DC/DC converter is applied to adjust the DC link voltages with several capacitors. The effect of the new harmonic elimination technique on the output quality of several single phase multilevel converters is explained in chapter 3 and 6 of this thesis. According to the electrical model of high power ultrasound transducer, this device can be modelled as parallel combinations of RLC legs with a main capacitor. The impedance diagram of the transducer in frequency domain shows it has capacitive characteristics in almost all frequencies. Therefore, using a voltage source converter to drive a high power ultrasound transducer can create significant leakage current through the transducer. It happens due to significant voltage stress (dv/dt) across the transducer. To remedy this problem, LC filters are applied in some applications. For some applications such as ultrasound, using a LC filter can deteriorate the performance of the transducer by changing its characteristics and displacing the resonance frequency of the transducer. For such a case a current source converter could be a suitable choice to overcome this problem. In this regard, a current source converter is implemented and applied to excite the high power ultrasound transducer. To control the output current and voltage, a hysteresis control and unipolar modulation are used respectively. The results of this test are explained in chapter 7.

The thesis deals with research of pulse compression of the acoustic signal in terms of applications in civil engineering. Based on the study and analysis of these methods, automated measuring equipment for non-destructive testing with pseudorandom sequence of maximum length and automated signal analysis, have been designed and implemented. In a single test cycle are obtained three parameters that characterize the linear and nonlinear behavior of the sample. A nonlinear parameter, Time of Flight of ultrasonic wave in the sample is further in the work compared with the conventional pulse measuring, and spectral analysis is compared with the method impact-echo. Functionality and optimization of the testing method was performed on a total of three sets of test pieces made of various building materials. The experiments proved simple result interpretation, and high sensitivity to structural damage associated with temperature loading. The results were correlated with conventional nondestructive methods and by destructive testing was measured change in compressive strength and flexural strength. This work also includes continual measurement of fundamental frequency influenced by moisture on a mortar sample. Use of pulse compression signal is in the civil engineering quite unusual. Only in recent years this topic is discussed in scientific articles with increasing frequency. Great potential lies in the association of three test methods into a single. Beneficial is high test speed and measurement reproducibility, but also theoretical possibility of testing massive test elements.

Ce travail de thèse est axé sur le domaine du traitement d’images biomédicales. L’objectif de notre étude est l’estimation des paramètres traduisant les propriétés mécaniques de l’artère carotide in vivo en imagerie échographique, dans une optique de détection précoce des pathologies cardiovasculaires. L’étude des comportements dynamiques de l’artère pour le dépistage précoce de l’athérosclérose constitue à ce jour une piste privilégiée. Cependant, malgré les avancées récentes, l’estimation du mouvement de la paroi carotidienne reste toujours difficile, notamment dans la direction longitudinale (direction parallèle au vaisseau). L’élaboration d’une méthode innovante permettant d’étudier le mouvement de la paroi carotidienne constitue la principale motivation de ce travail de thèse. Les trois contributions principales proposées dans ce travail sont i) le développement, la validation, et l’évaluation clinique d’une méthode originale d’estimation de mouvement 2D adaptée au mouvement de la paroi carotidienne, ii) la validation en simulation, et expérimentale de l’extension à la 3D de la méthode d’estimation proposée, et iii) l’évaluation expérimentale de la méthode proposée, en imagerie ultrasonore ultra-rapide, dans le cadre de l’estimation locale de la vitesse de l’onde de pouls. Nous proposons une méthode d’estimation de mouvement combinant un marquage ultrasonore dans la direction latérale, et un estimateur de mouvement basé sur la phase des images ultrasonores. Le marquage ultrasonore est réalisé par l’intermédiaire d’oscillations transverses. Nous proposons deux approches différentes pour introduire ces oscillations transverses, une approche classique utilisant une fonction de pondération spécifique, et une approche originale par filtrage permettant de contrôler de manière optimale leurs formations. L’estimateur de mouvement proposé utilise les phases analytiques des images radiofréquences, extraites par l’approche de Hahn. Ce travail de thèse montre que la méthode proposée permet une estimation de mouvement plus précise dans la direction longitudinale, et plus généralement dans les directions perpendiculaires au faisceau ultrasonore, que celle obtenue avec d’autres méthodes plus traditionnelles. De plus, l’évaluation expérimentale de la méthode sur des séquences d’images ultrasonores ultra-rapides issues de fantômes de carotide, a permis l’estimation locale de la vitesse de propagation de l’onde de pouls, la mise en évidence de la propagation d’un mouvement longitudinal et enfin l’estimation du module de Young des vaisseaux
This work focuses on the processing of biomedical images. The aim of our study is to estimate the mechanical properties of the carotid artery in vivo using ultrasound imaging, in order to detect cardiovascular diseases at an early stage. Over the last decade, researchers have shown interest in studying artery wall motion, especially the motion of the carotid intima-media complex in order to demonstrate its significance as a marker of Atherosclerosis. However, despite recent progress, motion estimation of the carotid wall is still difficult, particularly in the longitudinal direction (direction parallel to the probe). The development of an innovative method for studying the movement of the carotid artery wall is the main motivation of this thesis. The three main contributions proposed in this work are i) the development, the validation, and the clinical evaluation of a novel method for 2D motion estimation of the carotid wall, ii) the development, the simulation and the experimental validation of the 3D extension of the estimation method proposed, and iii) the experimental evaluation of the 2D proposed method in ultra-fast imaging, for the estimation of the local pulse wave velocity. We propose a motion estimation method combining tagging of the ultrasound images, and a motion estimator based on the phase of the ultrasound images. The ultrasonic tagging is produced by means of transverse oscillations. We present two different approaches to introduce these transverses oscillations, a classic approach using a specific apodization function and a new approach based on filtering. The proposed motion estimator uses the 2D analytical phase of RF images using the Hahn approach. This thesis work shows that, compared with conventional methods, the proposed approach provides more accurate motion estimation in the longitudinal direction, and more generally in directions perpendicular to the beam axis. Also, the experimental evaluation of our method on ultra-fast images sequences from carotid phantom was used to validate our method regarding the estimation of the pulse wave velocity, the Young’s modulus of the vessels wall, and the propagation of a longitudinal movement

Показано і обгрунтовано, що найбільш інформативним з параметрів, які відповідають за працездатність обсадних колон і визначають їх фактичний технічний стан, є геометричні параметри. На основі проведених теоретичних та експериментальних досліджень розроблено способи акустичного контролю геометричних параметрів трубних виробів зсередини та методологію застосування з цією метою акустичного луна-імпульсного методу контролю в експлуатаційних умовах свердловини. Експериментально досліджено залежність швидкості поширення поздовжньої ультразвукової хвилі в матеріалі обсадних труб та чутливості акустичного тракту від експлуатаційних факторів свердловини. Розроблено математичну модель контролю (роботи акустичного тракту та розрахунку акустичного поля) в умовах свердловини. Розроблено комплекс технічних засобів для акустичного контролю геометричних параметрів обсадних колон в свердловині.
Работоспособность обсадных колонн - один из главных факторов, влияющих на производительность и безопасность работы скважины. Отказы элементов обсадных колонн проявляются как при спуске и креплении колонны, так и во время освоения скважины и, особенно, в процессе ее продолжительной (более 20 лет) эксплуатации. Бывают случаи, когда через аварии с обсадными колоннами ликвидируют скважины, не выполнившие своего целевого назначения. Особенно актуальны вопросы контроля обсадных колонн подземных хранилищ газа, глубоких скважин и скважин, которые продолжительное время были на консервации. Практическое значение полученных результатов состоит в том, что разработанные способы и средства контроля позволяют: обеспечить контроль технического состояния обсадных колонн непосредственно в скважине; повысить надежность работы глубинного устройства благодаря использованию невращающейся системы сканирования и уменьшить её габаритные размеры благодаря использованию только одного измерительного канала и одного преобразователя, что играет значительную роль при конструировании средств внутритрубного контроля.
Is shown and prove that most informative parameters, which responsible for operational reliability of casing strings and which determine their actual technical condition, are the geometrical parameters. According to theoretical and experimental researches the means of the acoustic testing of geometrical parameters of pipes from their internal side and methodology of application with this purpose an acoustic pulse-echo method of the testing in operational conditions of a well was developed. Dependence of a speed of longitudinal ultrasonic wave propagation in a material of casing string and sensitivity of an acoustic tract from the operational factors experimentally are investigated. The mathematical model of the testing (of a work of an acoustic tract and estimation of an acoustic field) in conditions of a well is developed. The complex of means of the acoustic testing of geometrical parameters of casing strings in a well is developed.

A teoria da acustoelasticidade relaciona a variação de velocidade de propagação de ondas mecânicas à variação de tensão em um meio sólido. Em materiais frágeis como concreto, a danificação altera a velocidade de propagação paralelamente ao efeito acustoelástico. O objetivo deste trabalho é identificar e quantificar como a danificação e o efeito acustoelástico agem sobre a Velocidade de Pulso Ultrassônico (VPU) em corpos de prova de concreto submetidos a compressão uniaxial. Para tanto, foram realizadas três fases de ensaio. A primeira fase objetivou gerar dados para a análise da aplicação da interferometria de cauda de onda (Coda Wave Interferometry – CWI). Duas variações deste método foram estudadas e comparadas, com o propósito de determinar-se qual gera melhores resultados e quais parâmetros devem ser adotados para as análises. Para tal, um código computacional foi desenvolvido utilizando a linguagem Python 3.6.0. Foi constatado que a técnica do alongamento apresenta resultados melhores que a técnica tradicional da interferometria de cauda de onda. A segunda etapa foi dedicada ao estudo da variação de velocidade de propagação devido à recuperação de dano do corpo de prova. A terceira fase abordou a influência da geometria da amostra e da composição do concreto sobre a resposta do material à acustoelasticidade. Além disso, definiu-se um Índice de Dano (D) baseado na redução do módulo de elasticidade devido ao carregamento, a fim de isolar a variação de velocidade causada pelo efeito acustoelástico. Quanto ao estudo da recuperação de dano ao longo do tempo, a variação relativa de velocidade nas primeiras 24 horas após a retirada do carregamento se mostrou muito pequena em relação às variações geradas pelas condições de temperatura e umidade. Concluiu-se também que as amostras cilíndricas apresentaram respostas mais uniformes ao efeito acustoelástico que as amostras prismáticas. Por fim, o Índice de Dano se mostrou eficaz para isolar os efeitos da danificação e da acustoelasticidade sobre a VPU.
The acoustoelasticity theory relates the variation in propagation velocity of mechanical waves to the stress variation in a solid medium. In brittle materials such as concrete, damage affects the propagation velocity parallel to the acoustoelastic effect. This research aims to identify and quantify how damage and acoustoelastic effect act on Ultrasonic Pulse Velocity (UPV) in concrete samples subjected to uniaxial compression. In order to do so, three phases of testing were performed. The first one focused on generating data to analyze the application of the Coda Wave Interferometry (CWI). Two variations of this method were studied and compared, to the purpose of determining which variation shows better results and which parameters should be adopted in the analysis. To enable the analysis, a computational code using Python 3.6.0 language was developed. It was verified that the stretching technique shows better results than the traditional coda wave interferometry technique. The second phase was dedicated to study the variation in propagation velocity due to damage recovery in the sample. The third phase addressed the influence of the sample geometry and the concrete composition over the response from the material to the acoustoelasticity. Furthermore, a Damage Index (D) was defined based on the elastic modulus reduction due to loading, in order to isolate the variation of velocity due solely to the acoustoelastic effect. Regarding the study of damage recovery over time, the relative velocity variation in the first 24 hours following the withdrawal of the loading showed to be too little when compared to the variations caused by temperature and humidity conditions. It was also concluded that the cylindrical samples showed more uniform responses to the acoustoelastic effect than the prismatic samples. Finally, the Damage Index proved itself to be a reliable tool to isolate the effects of damage and acoustoelasticity over the UPV.

Ultrasound Imaging is widely used in biomedical and industrial applications, due to its non-invasive, non-destructive and non-ionizing nature. In the last 20 years, Ultrasound imaging has been continuously growing in both of these fields, since it has benefited from advances in electronic technologies and in signal processing methods. For industrial applications, a wide variety of instruments, based on ultrasound, have been designed to measure the properties and composition of materials and products. In particular, monitoring all of the steps of a production chain is crucial for process optimization and product quality in industries. In the medical area, ultrasound systems are widely used to investigate the tissue, by 2D morphological imaging, and the blood movement, by Doppler analysis. The large use of ultrasound equipment has further increased the research and the development activity of new investigation methods. Consequently, “open” systems capable of satisfying the research needs are in great demand. The activity of this PhD was focused on the design of new electronic architectures and systems capable of addressing some of the emerging needs in medical and industrial fields. In several industrial fields the products are checked by taking samples from the production chain, which are lately analyzed in specialized laboratories by using manual, expensive and time consuming operations. Systems capable of in-line and on-site monitoring products and materials would be of high value. For these reasons, we developed an ultrasound system for monitoring the properties of the fluids or suspensions flowing in pipes and another system to assess the concrete strength during the hydration process. The first one is a system with a wide range of applications, since a lot of products as food, medicines and cosmetics are in a fluid or suspension state during the production. It is a pulse wave system that measures the velocity profile of the fluids flowing in a pipe and uses the relation between the velocity profile and the fluid rheological properties to evaluate the quality of the products and keep the production chain under control. The second system evaluates the concrete strength, a parameter of paramount importance to guarantee durable and safe constructions. It is a pulse wave system that exploits a reflectometry technique to monitor the concrete strength evolution during the hardening process by analyzing the reflected signal at interface concrete-Plexiglas. In medical applications, High Frame Rate (HFR) imaging methods based on the transmission of defocused, plane-wave (PW) or multi-focused beams rather than single-focused beams, are increasingly popular. These methods lead to unprecedented performance that enables the reconstruction of 2D vector maps of the blood velocity distribution, or 3D investigations with improved resolution, but they are unfortunately very demanding in term of processing power. Therefore, the design and development of novel HFR methods and systems capable to efficiently implement the HFR imaging methods, is a crucial challenge. Toward this goal the Micro Systems Design Laboratory (MSD Lab) of the University of Florence developed a novel research scanner called ULtrasound Advanced Open Platform 256 (ULA-OP 256). ULA-OP 256 can independently manage up to 256 transmit/receive (TX-RX) channels. It has high computational power in a small size, compatible with mobility. The system supports a wide range of transmission/receiving strategies, processes data in real time, stores data for post-processing, and can be connected to matrix probes. In particular, the platform implements an advanced beamformer architecture, named Multi-Line Parallel Beamformer (MLPBF). MLPBF exploits a combination of parallel and serial processing strategies that make HFR imaging possible.

碩士
國立清華大學
電機工程學系
102
Recently, pulsed magnetomotive ultrasound (pMMUS) imaging has been introduced to detect superparamagnetic iron oxide nanoparticles (SPIO) which is not able to be visualized by conventional ultrasound. However, because of the used magnetic short pulse, the reported pMMUS only can use a single-element ultrasound transducer along with mechanical scanning to perform imaging, which significantly limits the imaging fame rates. To solve this problem, we propose an ultrafast plane wave imaging based pMMUS technique. The ultrafast frame rate of plane wave imaging is fast enough to track the magneto-motion of the excited SPIOs during the period of the magnetic pulse being applied. Therefore, the proposed ultrafast plane wave pMMUS is capable of visualizing the dynamic response of the excited SPIOs, which is highly correlated to tissue characteristics such as viscosity and elasticity, to an externally-applied magnetic pulse. In addition, a new pMMUS motion tracking algorithm based on ultrafast plane wave imaging is developed to reduce the effect of magnetic field inhomogeneity. In our experiments, ultrafast plane wave imaging with a 5 kHz frame rate was used to implement the pMMUS where the SPIO motion induced by an 8-ms magnetic pulse was tracked. The results showed that there were significant differences between the ultrafast plane wave pMMUS images of the phantoms with and without SPIOs embedded. There was a monotonic increase in displacement with increased concentration of SPIOs. In addition, agarose phantoms with 0.5%, 1% and 1.5% agarose were used to mimic tissues with different elasticity. The dynamic responses of the excited SPIOs in the three types of phantoms were distinguishable. Overall, it is demonstrated that the feasibility of our proposed ultrafast plane wave pMMUS imaging technique for the visualization of the magneto-motion and dynamic response of the SPIOs under the excitation of a short magnetic pulse. More studies are required to further improve the magneto-motion tracking algorithm and explore the relationship between the dynamic response of the excited SPIOs and the tissue viscosity and elasticity.

碩士
國立臺灣大學
生醫電子與資訊學研究所
100
Cerebral vascular diseases (strokes) account for the third highest cause of death in Taiwan. There are mainly two types of stroke, ischemic (clogging of brain vessel) and hemorrhagic (burst of brain vessel) strokes. The permanent disability caused by stroke also creates a huge cost for the society. Currently, Doppler ultrasound systems are used to detect vessel flows in the heart or intracranial region during the open-heart operation and stroke patients monitoring. However, the operation of transcranial Doppler (TCD) ultrasound systems requires experienced medical personnel and the Doppler gate seeking is done manually. Furthermore, the wires connecting the systems often restrict the angle and range of operation for the examiners. In order to perform faster diagnosis for stroke symptoms, automatic vessel detecting algorithm (AVDA) finding the Doppler gate (depth interval) of the phantom vessel and common carotid arteries is developed. The algorithm stresses on the depth interval where best flow signal can be obtained. In the early stage, a 5 MHz linear ultrasound transducer and CompuFlow 1000 are used to construct an ultrasound system. Under the phantom setup, the velocity scale AVDA locates the correct Doppler gate at starting depth of 34.18mm. Likewise, the vessel range for the Doppler gate is accurately determined to be at 28.64~32.34mm for the common carotid data from using the waveform AVDA. In the post image processing, adaptive pulse coupled neural network denoising (AD-PCNN) technique is used to improve the image SNR from 8.70 to 21.72 dB, and able to effectively inhibit additional noise at 10 dB. A wireless TCD system is designed under collaboration between various labs funded by National System on Chip’s (NSOC) grant. The wireless data transfer is inspected by experimenting over a phantom vessel with peristaltic pump. The wireless TCD system is able to correctly input and output flow signal from the transducer to the end display on the computer. The implemented 60 GHz wireless module and computed unified device architecture (CUDA) can provide fast data transferring (~1 Gb/s) and calculation of the Doppler spectrogram. Not only the spectrogram can be executed real-time for the patient diagnosis, the data can be transferred wirelessly into the hospital server. For future work, we wish to integrate the AVDA and the NSOC wireless TCD system to achieve automatic vessel detection in clinical settings.

碩士
國立臺灣大學
應用力學研究所
86
Abstract An image processing system is developed for the analysis of medica l images from various sources , the traces of curves in the image are digitize d and processed to provide the dynamic of Bio-motion . Our image processin g system are validated with a few clinical examples . (1) CCA (Common Carotid Artery ) impedance measurements : The normal side of CCA occlusion patients an d normal subjects have the same results .The first harmonic of illed side is l arger than the normal side ,and the impedance increase at frequencies before t heir fifth harmonic .For one side CCA hemorrhagic infarction patients ,the res ults show low frequency impedance increases for both sides. (2) PWV (Pulse Wav e Velocity) measurement of Popliteal a. to Dorsal Pedis a. : We find PWV incre ases when normal subjects change their position from supine to stand ,but the DM patients show different results ,and both legs associated with may have lar ge difference . The changes of PWV may be autonomic and muscle contraction abi lity .(3) Pressure and blood vessel variation measurements : The curviliner sh ap of pressure/diameter curve was observed which reveals the characteristics of pressure/diameter curve was observed which reveals the characteristics of the viscoelasticity of the blood vessel .During the change of blood pressure ,the contribution from the elastin fiber and collagen fiber varies which agree we ll with the literature. Keyword : edge detection ,CCA ,CCA occlusion ,ultrasound doppler ,blood vesse impedance

碩士
國立臺灣大學
醫學工程學研究所
107
Background and Purpose: Melanoma is a malignant tumor that arises from uncontrolled proliferation of melanocytes. Advanced melanoma is the most aggressive, metastatic and deadly skin cancer, and 40-50% patients with advanced melanoma are diagnosed with brain metastasis in clinic. The main reason that melanoma brain metastasis remain untreatable is due to the blood-brain-barrier/blood-tumor-barrier (BBB/BTB). In this study, the synergistic effects of low-dose pulsed-wave focused ultrasound hyperthermia (pUH) on the delivery and therapeutic efficacy of pegylated liposomal doxorubicin (PLD) for melanoma brain metastases are investigated. Materials and Methods: In this study, the synergistic effects of pulsed-wave ultrasound hyperthermia and anticancer drug PLD in vitro and in vivo were investigated. B16F10 melanoma cells transfected with GFP were used in the experiments. Different concentration of PLD with/without pUH were used in the cultured cells for 24 and 72 h. Cell viability was evaluated by MTT assay. In animal models, B16F10-GFP cells were injected into the female striatum of C57BL/6 mice, and 6 days later the mice were divided into four groups (control, PLD, pUH, PLD+pUH) and received treatment. The mice were I.V. injected with PLD (5 mg/kg) with/without pUH one-minute after drug injection. The parameters of ultrasound were frequency at 500 kHz, PRF at 1000 Hz, duty cycle at 50%, and sonication duration at 10 min. The tumor growth was captured and assessed every other day by IVIS system. DOX in brain and tumor tissues were quantified after animal sacrification. The tissues were histologically processed with H&E, PLD distribution, IHC, TUNEL assay, and evaluation of apoptosis-related protein expression in the tumor was conducted via Western blot. Results: The inhibitory effects of PLD alone on cancer cells depended on the concentration and treatment time. PLD with ultrasound sonication caused significant inhibition on the cancer cells (p<0.0001). In vivo, the parameters of ultrasound were determined by the safety of hyperthermia on normal brain tissue and the delivery of the drug to the brain tumor. The tumor size and morphology were influenced with PLD and pUH treatment and inhibited the tumor growth development. Drug was cumulated much more in the tumor tissue than in the normal brain for the combined therapy. The therapeutic efficacy of PLD plus ultrasound hyperthermia were demonstrated by IHC (Ki-67 and Caspase-3 staining) and TUNEL assay. PLD+pUH induced more apoptosis on the melanoma brain tumor by Western blot analysis. Conclusion: These results support that low-dose pulsed-wave ultrasound hyperthermia could enhance the PLD delivery into brain tumors. The anticancer drug could be effectively cumulated in the sonicated tumor and further inhibited the tumor growth without damaging the normal brain tissues.

Current bio-robotic assistive devices have developed into intelligent and dexterous machines. However, the sophistication of these wearable devices still remains limited by the inherent difficulty in controlling them by sensing user-intention. Even the most commonly used sensing method, which detects the electrical activity of skeletal muscles, offer limited information for multi-function control. An alternative bio-sensing strategy is needed to allow for the assistive device to bear more complex functionalities. In this thesis, a different sensing approach is introduced using Pulsed-Wave Doppler ultrasound in order to non-invasively detect small tendon displacements in the hand. The returning Doppler shifted signals from the moving tendon are obtained with a new processing technique. This processing technique involves a unique way to acquire raw data access from a commercial clinical ultrasound machine and to process the signal with Fourier analysis in order to determine the tendon displacements. The feasibility of the proposed sensing method and processing technique is tested with three experiments involving a moving string, a moving biological beef tendon and a moving human hand tendon. Although the proposed signal processing technique will be useful in many clinical applications involving displacement monitoring of biological tendons, its uses are demonstrated in this thesis for ultrasound-based user intention analysis for the ultimate goal of controlling assistive exoskeletal robotic hands.

碩士
國立臺灣科技大學
電機工程系
104
Doppler ultrasound is one of the main blood flow measurement tools in clinical diagnosis. Miniaturization of medical devices including ultrasound systems has become an important trend due to the advantages of high portability and low-cost. In this study, a 10MHz pulsed Doppler ultrasound system was developed for flow measurement. The primary circuits include high- frequency and high-speed electronic devices for demodulation, filtering, and sample-and-hold. In addition, the system uses an ARM Cortex-M3 based microcontroller (MCU) for real-time digital signal processing. The ARM-based MCU also offers two analog to digital converters(ADC) and has the advantages of low power and low cost. The analog Doppler signals were digitalized via the ADC on the same MCU for better integration and a Liquid Crystal Module (LCM) displays the Doppler spectrum. Performance of the Doppler system was examined using blood flow phantom. Results indicate that the detected flow velocity is proportional to the actual flow velocity.

临床及动物实验的文献报告表明, 低能量脉冲超声波 (LIPUS) 能促进骨折愈合。 可是, 不同研究小组针对LIPUS的功效所提供的数据结果往往并不一致。为了找出导致数据结果不一致的原因, 以及提升LIPUS的生物功效, 科研人员正致力于测定超声波在骨折治疗中的最佳信号参数。 在临床运用上, LIPUS对骨折的治疗一般是以经皮方式应用的。 故此, 不同层次深度的骨折会暴露在不同的超声波场区里。 超声波场有两个不同的区域, 就是近场区 (接近超声波换能器的区域) 及远场区 (远离超声波换能器的区域)。 在我们早期的临床研究中, 我们曾使用超声波的近场区治疗胫骨的复杂性骨折。 我们发现, 当超声波换能器置于胫骨骨折处的前方, 骨痂集中生成于胫骨骨折处的背面。 这研究结果显示, 近场区以外的超声波场或许更具促进骨痂形成的功效。 再者, 针对LIPUS声场仿真分析的结果显示, 近场区内的声压分布是不稳定的, 而远场区内的声压则远比近场区的均及稳定。由于声压的稳定性会大大影响超声波于组织内的能量透射, 我们相信在超声波场中, 骨折的深度会影响LIPUS的生物效应。
本研究采用大鼠闭合性股骨骨折模型及细胞培养实验, 探究不同的超声波场区对骨折愈合的影响。本研究作出了以下三个科研假设: (1) LIPUS 的远场区在促进骨折愈合的应用上有着更高的生物效应; (2) LIPUS 的远场区能透过促使骨细胞产生旁分泌调节因子, 从而提升成骨细胞的成骨活性; (3) 通过换能器直径的调制而产生的LIPUS远场区能有效地促进骨折愈合。
在第一部分的实验里, 股骨骨折的SD大鼠被随机分为对照组 (control), 近场区超声波治疗组 (near field; 伤肢跟换能器相距0mm), 中近场区超声波治疗组 (mid-near field; 伤肢跟换能器相距60mm), 远场区超声波治疗组 (far field; 伤肢跟换能器相距130mm)。在伤肢及超声波换能器之间安放了跟软组织具有同一超声波衰减系数的凝胶 (长度: 0mm, 60mm, 130mm)。LIPUS每天治疗20分钟, 每周治疗5天。 我们研究结果显示, 治疗后的第四周, 远场治疗组的骨痂组织具有各组中最高的相对骨体积及组织矿密度, 这造就远场治疗组相比对照组具有更强的力学属性。我们的研究结果表明, LIPUS的远场区治疗能通过提升骨痂的骨体积及骨矿化, 进一步促进骨折的愈合。
在第二部分的实验里, 我们把骨细胞株(MLO-Y4) 暴露在三種不同的超声波場中: 0 mm, 60 mm 及130 mm 。 经过不同的LIPUS处理后, 我们把条件培养基(CM) 收集, 并将其用于培养成骨前趋细胞株(MC3T3-E1)。 这部分的实验共有5组: Non组(非条件培养基处理组), Con组(骨细胞条件培养基处理组), 0mm组(条件培养基处理组; 条件培养基收集自经过LIPUS近场区刺激后的骨细胞), 60mm组(条件培养基处理组; LIPUS中近场区刺激后的骨细胞), 以及 130mm组(条件培养基处理组; LIPUS远场区刺激后的骨细胞)。我们测试了各超声波场对骨细胞的直接影响, 以及成骨前趋细胞经过各类骨细胞条件培养基培养后的成骨活性。 免疫染色的结果显示近场区以后的超声波场 (130mm 及 60mm) 能进一步诱导β-catenin 于骨细胞的入核作用。 另外, 远场区的骨细胞条件培养基 (130mm CM) 的处理促进了成骨前趋细胞的: (1) 细胞迁移的能力 (反映自细胞伤口愈合测试) ; (2) 细胞分化成熟的机制 (BrdU细胞增殖检验及ALP活性分析): (3) 基质钙化 (Alizarin red 钙化结节染色)。
在第三部分的实验里, 我们把换能器的直径缩减致一半, 以致换能器跟LIPUS远场区之间的距离从130 mm被拉近至30 mm。 当LIPUS以经皮的方式应用, 位于皮下大约40 mm的大鼠股骨骨折因此暴露在LIPUS的远场区。 相对于在换能器及伤肢之间安置130 mm凝胶, 以调制换能器直径而直接让骨折暴露于LIPUS远场区是更具临床应用性的方法。 在这部分, 股骨骨折的SD大鼠被随机分为对照组 (control), LT-Near30 (正常的换能器直径; 近场超声处理; I[subscript SATA] = 30 mW/cm²), ST-Far30 (缩减后的换能器直径; 远场超声处理; I[subscript SATA] = 30 mW/cm²), ST-Far150 (缩减后的换能器直径; 远场超声处理; I[subscript SATA] = 150 mW/cm²)。 研究结果证实, 以调制换能器直径而产生的远场LIPUS (ST-Far30)能透过提升骨痂的生成及力学属性, 进一步促进骨折愈合。 同时, 我们的结果显示, 相对高强度 (150 mW/cm²) 的远场LIPUS治疗不能更有效地促进骨折愈合。
综上所述, 动物及细胞培养实验结果证明, LIPUS的远场区在促进骨折愈合上更具功效。由于LIPUS的远场区放射稳定的超声波束, 骨痂中的骨细胞受引发释放可溶性因子, 从而进一步激发成骨样细胞的成骨活性。 这些细胞的生物效应造就LIPUS的远场区在促进骨折愈合上更具治疗效果。最后, 我们亦把以上的研究发现转化成具临床应用性的LIPUS应用方法。 这应用方法能让超声波换能器以紧贴皮肤的方式直接使骨折暴露于LIPUS远场区, 从而达成促进骨折愈合的功效。
Low-intensity Pulsed Ultrasound (LIPUS) has been confirmed to enhance fracture healing in many clinical and animal studies. However, the evidences from literatures to support the applications of LIPUS on fracture healing were inconsistent. Therefore, scientists have been studying various ultrasound parameters aiming to find out the factors resulting in the inconsistent outcomes among research groups, and to further enhance the efficacy of LIPUS. Clinically, LIPUS is usually applied onto fracture sites transcutaneously, hence, fractures at different depths are exposed to different zones of ultrasound beam. There are two characteristic zones of ultrasound beam: the near field (close to the transducer) and far field (farther from the transducer). In our previous clinical study, direct transcutaneously applied LIPUS (near field LIPUS exposure) was used to treat human tibial complex fractures. We found that callus usually formed on the posterior side when the transducer was placed on the anterior side. This finding implied that ultrasound beam beyond near field bears higher potential in promoting callus formation. Moreover, beam mapping measurement of LIPUS shows a variable spatial pressure in near field; while a more uniform pressure profile was found beyond it (far field). As the stability of pressure profile influences the ultrasound energy transmission in tissue, we postulate that the biological effects of LIPUS are affected by the fracture depths within the ultrasound field.
This study aims to address the research question of how ultrasound fields influence the fracture healing through testifying the following hypotheses in animal and cell culture studies: (1) Far field LIPUS bears higher biological effect in facilitating fracture healing; (2) Far field LIPUS could enhance the osteogenic activities of osteoblastic cells via paracrine factors secreted from osteocytes; (3) Far field LIPUS setup by transducer diameter modulation could facilitate fracture healing.
In part one study, femoral fractured Sprague-Dawley (SD) rats were randomized into control, near-field (fractures placed at 0mm away from transducer), mid-near field (60mm away from transducer) or far-field (130mm away from transducer) groups. Rubber gel block (lengths: 0mm, 60mm and 130mm) with attenuation coefficient equivalent to soft tissue was interposed between the transducer and the fractured limb. LIPUS was given 20min/day and 5days/week. We found the callus in 130mm group was the highest in bone volume fraction and tissue mineral density at week 4. These advancements mutually contributed to its significantly stronger mechanical properties than the control group. Our results indicated that far field LIPUS could further facilitate fracture healing by promoting bone volume increase and callus mineralization, which led to enhanced mechanical properties.
In part two study, LIPUS was applied to osteocyte cell line (MLO-Y4) at three distances: 0mm, 60mm and 130mm. The conditioned medium (CM) collected from different LIPUS treatment regimens were used to culture pre-osteoblast cell line (MC3T3-E1). There were 5 groups in the CM treatment: Non group (plain α-MEM treatment), Con group (osteocyte CM), 0mm group (Near field LIPUS treated osteocyte CM), 60mm group (Mid-near field LIPUS treated osteocyte CM) and 130mm group (Far field LIPUS treated osteocyte CM). The effect of ultrasound fields on osteocytes and the osteogenic activities of the pre-osteoblasts after different CM treatments were assessed. The immunostaining results indicated that beyond near field LIPUS (LIPUS at 130mm and 60mm) could further promote β-catenin nuclear translocation in osteocytes. The far field LIPUS osteocyte-CM (130mm group) caused the highest biological effect on (1) pre-osteoblasts migration (reflected by wound healing assay); (2) maturation of pre-osteoblasts: transition of cell proliferation into osteogenic differentiation (BrdU cell proliferation assay and ALP activity assay); and (3) matrix calcification (Alizarin red calcium nodule staining).
In part three study, the transducer diameter was reduced by half in order to draw the far field location closer to the transducer (i.e. from 130 mm to 30 mm). As the femoral shaft fractures of rats are located at around 40 mm beneath the skin, fractures were directly exposed to far field LIPUS transcutaneoulsy. It is a more clinically applicable approach than the method of physical separation (i.e. 130 mm separation between transducer and fractured limb). Femoral fractured SD rats were randomized into control, LT-Near30 (conventional transducer diameter, near field, I[subscript SATA] = 30 mW/cm²), ST-Far30 (small transducer, far field, I[subscript SATA] = 30 mW/cm²) and ST-Far150 (small transducer, far field, I[subscript SATA]=150 mW/cm²). Our results confirmed that the far field LIPUS emitted from the transducer diameter reduction setup (ST-Far30) could further facilitate fracture healing process by enhancing callus formation and mechanical properties. Our findings also indicated that fractures exposed to far field LIPUS with relatively higher intensity (150 mW/cm²) did not heal better.
In summary, our in vivo and in vitro findings reinforce each other to confirm the positive effects of far field LIPUS on promoting fracture healing. As far field LIPUS radiates a stable ultrasound beam, osteocytes inside the callus are triggered to secrete soluble factors to promote the osteogenic activities of osteoblastic cells. This contributes to the higher therapeutic effects of far field LIPUS on fracture healing. We also translated these findings to establish a clinically applicable LIPUS device, which directly radiates far field LIPUS to subcutaneous fracture site without any distance separation needed.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Fung, Chak Hei.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2012.
Includes bibliographical references (leaves 186-207).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstract also in Chinese.
Abstract --- p.i
中 文 摘 要 --- p.v
Publications --- p.ix
Acknowledgements --- p.xii
List of Abbreviations --- p.xiii
Index for Figures --- p.xvi
Index for Tables --- p.xviii
Chapter Chapter 1. --- Introduction and Literature Review --- p.1
Chapter 1.1 --- Long Bone Fracture - A Growing Global Challenge --- p.2
Chapter 1.2 --- Long-Bone Fracture - Current Management and Limitations --- p.5
Chapter 1.3 --- Cellular Biology of Fracture Healing --- p.7
Chapter 1.3.1 --- Stage 1: Inflammation --- p.7
Chapter 1.3.2 --- Stage 2: Soft callus formation --- p.8
Chapter 1.3.3 --- Stage 3: Hard callus formation --- p.9
Chapter 1.3.4 --- Bone Remodeling --- p.10
Chapter 1.4 --- Biophysical Stimulation to Bone --- p.13
Chapter 1.5 --- Low-intensity Pulsed Ultrasound --- p.14
Chapter 1.5.1 --- Application of LIPUS on Fracture Healing --- p.14
Chapter 1.5.2 --- Physics of Ultrasound --- p.16
Chapter 1.5.3 --- Ultrasound Parameters --- p.20
Chapter 1.5.3.1 --- Ultrasound Frequency --- p.20
Chapter 1.5.3.2 --- Duty Cycle --- p.22
Chapter 1.5.3.3 --- Intensity --- p.22
Chapter 1.5.3.4 --- Angle of Incidence --- p.24
Chapter 1.5.3.5 --- Ultrasound Field --- p.25
Chapter 1.5.4 --- Possible Mechanism of LIPUS on Tissue --- p.31
Chapter 1.5.4.1 --- Thermal Effect --- p.31
Chapter 1.5.4.2 --- Cavitation --- p.31
Chapter 1.5.4.2 --- Acoustic Streaming --- p.32
Chapter 1.5.4.3 --- Frequency Resonance Hypothesis --- p.32
Chapter 1.5.4.4 --- Micromotion --- p.33
Chapter 1.6 --- Possible Cellular and Molecular Mechanotransduction Mechanism of LIPUS --- p.34
Chapter 1.6.1 --- Osteocyte: Potential Mechanosensor --- p.34
Chapter 1.6.3 --- Osteocyte-osteoblast mechanotransduction --- p.39
Chapter 1.7 --- Hypothesis --- p.39
Chapter 1.8 --- Study Plan and Objectives --- p.40
Chapter 1.8.1 --- Study Plan --- p.40
Chapter 1.8.2 --- Objectives --- p.42
Chapter Chapter 2. --- Characterization of Ultrasound Field Distances on Rat Fracture Model --- p.43
Chapter 2.1 --- Introduction --- p.44
Chapter 2.2 --- Material & Methods --- p.47
Chapter 2.2.1 --- Closed Femoral Shaft Fracture Model in Rat --- p.47
Chapter 2.2.2 --- Ultrasound Field Distances Setup --- p.51
Chapter 2.2.3 --- Animal Grouping & LIPUS Treatment Protocol --- p.53
Chapter 2.2.4 --- Assessments --- p.56
Chapter 2.2.4.1 --- Radiological Analysis --- p.56
Chapter 2.2.4.2 --- Micro-computed Tomography --- p.61
Chapter 2.2.4.3 --- Histomorphometry --- p.64
Chapter 2.2.4.4 --- Mechanical Testing --- p.66
Chapter 2.2.4.5 --- Statistical Analysis --- p.66
Chapter 2.3 --- Results --- p.68
Chapter 2.3.1 --- Radiological Analysis --- p.71
Chapter 2.3.2 --- MicroCT --- p.77
Chapter 2.3.3 --- Histomorphometry --- p.82
Chapter 2.3.4 --- Mechanical Testing --- p.85
Chapter 2.4 --- Discussion --- p.87
Chapter 2.4.1 --- Far Field LIPUS Enhances Mechanical Properties of Healing Callus --- p.88
Chapter 2.4.2 --- Mid-near field and Near field LIPUS Enhances Woven Bone Formation --- p.90
Chapter 2.4.3 --- The Biological Effects of LIPUS with Different Ultrasound Field Exposure --- p.94
Chapter 2.5 --- Conclusion --- p.97
Chapter Chapter 3. --- The Effect of Ultrasound Field Distances on Bone Cells --- p.100
Chapter 3.1 --- Introduction --- p.101
Chapter 3.2 --- Material & Methods --- p.102
Chapter 3.2.1 --- Cell Culture --- p.102
Chapter 3.2.2 --- Ultrasound Field Distances Setup & Treatment Protocol --- p.102
Chapter 3.2.2 --- Immunostaining of β-catenin --- p.106
Chapter 3.2.3 --- Wound Healing Assay --- p.109
Chapter 3.2.4 --- BrdU Cell proliferation Assay --- p.111
Chapter 3.2.5 --- Alkaline phosphatase activity assay --- p.112
Chapter 3.2.6 --- Alizarin calcium nodule staining --- p.113
Chapter 3.2.7 --- CM characterization - PGE₂ ELISA assay --- p.114
Chapter 3.2.8 --- CM characterization - nitrite assay --- p.114
Chapter 3.2.9 --- Statistical Analysis --- p.115
Chapter 3.3 --- Results --- p.116
Chapter 3.3.1 --- Immunostaining of β-catenin --- p.116
Chapter 3.3.2 --- Wound healing assay --- p.119
Chapter 3.3.3 --- BrdU Cell proliferation Assay --- p.119
Chapter 3.3.4. --- Alkaline phosphatase activity assay --- p.122
Chapter 3.3.5 --- Alizarin calcium nodule staining --- p.122
Chapter 3.3.6. --- CM characterization - PGE₂ ELISA assay --- p.125
Chapter 3.3.7 --- CM characterization - nitrite assay --- p.125
Chapter 3.4 --- Discussion --- p.128
Chapter 3.4.1 --- The Osteogenic Effect of Far Field LIPUS-Osteocyte Conditioned Medium --- p.128
Chapter 3.4.2. --- Mechanisms of Mechanotransduction between Osteocyte and Osteoblast --- p.131
Chapter 3.5 --- Conclusion --- p.136
Chapter Chapter 4. --- Rat Fracture Exposed to Far Field LIPUS by Modulating Ultrasound Transducer Diameter --- p.139
Chapter 4.1 --- Introduction --- p.140
Chapter 4.2 --- Material & Methods --- p.143
Chapter 4.2.1 --- Closed Femoral Shaft Fracture Model in Rat --- p.143
Chapter 4.2.2 --- Ultrasound Field Distances Setup & Treatment Protocol --- p.143
Chapter 4.2.3 --- Assessments --- p.148
Chapter 4.2.3.1 --- Radiological Analysis --- p.148
Chapter 4.2.3.2 --- Micro-computed Tomography --- p.148
Chapter 4.2.3.3 --- Histomorphometry --- p.149
Chapter 4.2.3.4 --- Mechanical Testing --- p.151
Chapter 4.2.3.5 --- ex vivo Temperature Measurements --- p.151
Chapter 4.2.3.6 --- Statistical Analysis --- p.151
Chapter 4.3 --- Results --- p.152
Chapter 4.3.1 --- Radiological Analysis --- p.154
Chapter 4.3.2 --- MicroCT --- p.157
Chapter 4.3.3 --- Histomorphometry --- p.160
Chapter 4.3.4 --- Mechanical Testing --- p.166
Chapter 4.3.5 --- ex vivo Temperature Measurement --- p.168
Chapter 4.4 --- Discussion --- p.170
Chapter 4.4.1 --- Far field LIPUS Setup by Transducer Diameter Modulation Enhanced Fracture Healing --- p.170
Chapter 4.4.2 --- Fractures Exposed to Far Field LIPUS with Higher Intensity Did Not Heal Better --- p.174
Chapter 4.4.3 --- Biphasic Effect of LIPUS Intensities on Fracture Healing --- p.176
Chapter 4.5 --- Conclusion --- p.178
Chapter Chapter 5. --- Conclusion --- p.179
Chapter 5.1 --- Differential Biological Effects of Ultrasound Fields --- p.180
Chapter 5.2 --- Far Field LIPUS exposure can be achieved by transducer diameter modulation --- p.181
Chapter 5.3 --- Biphasic Effect of Ultrasound Intensities on Fracture Healing --- p.181
Chapter 5.4 --- Mechanotransduction between Osteocyte and Osteoblastic cells --- p.182
Chapter 5.5 --- Clinical Implications --- p.183
Chapter 5.6 --- Future Investigations --- p.184
Chapter 5.7 --- Limitations --- p.184
Bibliography --- p.186
Appendix --- p.208

A dissertation submitted in partial compliance with the requirements for the Master's Degree in Technology: Chiropractic, Durban Institute of Technology, 2002.
Plantar fasciitis (PF) is a syndrome that causes pain at the insertion of the plantar fascia to the medial calcaneal tubercle of the calcaneaus. This syndrome has been described as an overuse injury with subsequent inflammation at the insertion of the plantar fascia to the bone. The literature describes inflammatory changes that occur within the body and attachment of the plantar fascia, together with biomechanical aberrances that may be the result of the PF. The purpose of this study was to determine the relative effectiveness of pulsed ultrasound as an adjunct to foot manipulation in the treatment of plantar fasciitis. The foot manipulations are used to correct the biomechanical abnormalities, while the pulsed ultrasound is used for its anti-inflammatory properties. The combination of pulsed ultrasound and foot manipulation was compared to foot manipulation alone to determine if this ultrasound manipulation combination had any beneficial effect over and above foot manipulation alone. Thus determining whether it is of importance to o approach and treat both aspects of the syndrome described. This was a prospective, randomised, comparative controlled trial. Forty subjects were diagnosed with plantar fasciitis and chosen to participate in the study. They were subsequently divided into two groups (Group A and Group B) of twenty. Group A was the experimental group receiving foot manipulation and ultrasound as treatment, and Group B, the control group received foot manipulation alone as treatment. Each subject received six treatments within a period of three weeks, with a seventh follow-up within one week of the sixth treatment. There was no treatment at the seventh consultation; this was used for obtaining subjective and objective readings. Subjective assessment was by means of the Foot Function Index, and objective was by means of the manual algometer. Both the subjective. and objective readings were taken prior to the first, sixth and at the seventh (final) consultations.
M

Thesis (M.Tech.: Chiropractic) - Dept. of Chiropractic, Durban Institute of Technology, 2003 1 v. (various pagings)
This study was a prospective, randomised, double blinded, placebo controlled, comparative clinical trial to establish the efficacy of therapeutic ultrasound and compare the effectiveness of the two waveforms of ultrasound in the treatment of myofascial pain syndrome.

Ultrasound imaging techniques have become increasingly successful in the medical field as they provide relatively low cost and totally safe diagnosis. Doppler methods focus on blood flow for the diagnosis and follow-up of cardiovascular diseases. First Doppler methods only measured the axial component of the motion. More recently, advanced methods have solved this problem, by estimating two or even all three velocity components. In this context, high frame rate (HFR) imaging techniques, based on the transmission of plane waves (PW), lead to the reconstruction of 2-D and 3-D vector maps of blood velocity distribution. The aim of this Ph.D. project was to develop novel acquisition schemes and processing methods for advanced ultrasound Doppler systems. Each development step was based on simulations and experimental tests. Simulations were based on Field II©, while experiments were conducted by using the ULA OP 256 open scanner. In particular, the recently proposed 2-D HFR vector flow imaging (VFI) method (DOI: 10.1109/TUFFC.2014.3064), based on the frequency domain for displacement estimation, was thoroughly investigated. Three main issues were addressed: the high underestimation of blood flow velocity observed when examining vessels at great depths, the high computational load, which hindered any real-time implementation and the lack of information about the third velocity component. Specifically, the progressive broadening of the transmitted beam on the elevation plane due to the acoustic lens was demonstrated to be responsible for the underestimation. The computational cost was reduced by processing demodulated and down-sampled baseband data instead of radiofrequency data, and a preliminary real time version of the 2-D VFI method was implemented. It was also found that a more efficient implementation could be obtained by exploiting parallel computing and graphic processing units (GPUs). An expansion circuit board for the ULA-OP 256 hardware, which allocates GPU resources, was thus designed and built. This new system architecture may allow the implementation of even more complex algorithms, such as the 3-D VFI methods. In particular, it will be possible to implement the novel method for 3D VFI that was developed and tested during this Ph.D. project. Such method suitably extended the 2D VFI approach by proposing an efficient estimation strategy that considerably limits the overall computational load.

Wei, Fangyuan.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2013.
Includes bibliographical references (leaves 182-211).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstract also in Chinese.

Hui, Fan Fong.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2009.
Includes bibliographical references (leaves 153-181).
Abstract also in Chinese.
Acknowledgements --- p.ii
Abstract --- p.iii
Abbreviations --- p.vii
Table of Contents --- p.ix
List of Tables --- p.xv
List of Tables --- p.xv
List of Figures --- p.xvi
Major Conference Presentations --- p.xix
Publications in Preparation --- p.xxii
Chapter Chapter 1 --- Study Background --- p.1
Chapter 1. --- Introduction --- p.2
Chapter 1.1. --- Spinal Deformities --- p.2
Chapter 1.1.1. --- Treatment --- p.2
Chapter 1.2. --- Spinal fusion --- p.4
Chapter 1.2.1. --- Gold Standard of Spinal Fusion --- p.4
Chapter 1.2.2. --- Decortication in Spinal Fusion --- p.4
Chapter 1.2.3. --- Autograft in Spinal Fusion --- p.4
Chapter 1.2.4. --- Local Factors Influencing Spinal Fusion --- p.5
Chapter 1.2.5. --- Ultimate Goals of Spinal Fusion --- p.7
Chapter 1.2.6. --- Limitations of Spinal fusion --- p.7
Chapter 1.3. --- Alternatives of Different Components for Enhancing Spinal Fusion
Chapter 1.3.1. --- Bone Graft Substitute --- p.9
Chapter 1.3.2. --- Bioactive Factors --- p.15
Chapter 1.4. --- Limitations of the Alternative Methods in Spinal Fusion Enhancement --- p.19
Chapter 1.4.1. --- BMPs --- p.19
Chapter 1.4.2. --- Gene Therapy --- p.20
Chapter 1.4.3. --- Biophysical Stimulation --- p.20
Chapter 1.5. --- Recent Methods in Enhancing Spinal Fusion --- p.21
Chapter 1.5.1. --- Low Intensity Pulsed Ultrasound --- p.21
Chapter 1.5.2. --- Mesenchymal Stem Cells in Spinal Fusion --- p.24
Chapter 1.6. --- Conclusion --- p.26
Chapter Chapter 2 --- "Hypothesis, Objectives and Plan of Study" --- p.29
Chapter 2. --- "Hypothesis, Objectives and Plan of Study" --- p.30
Chapter 2.1 --- Study Hypothesis --- p.31
Chapter 2.2 --- Study Objectives --- p.31
Chapter 2.3 --- Plan of Study --- p.32
Chapter 2.3.1 --- For First Objective --- p.32
Chapter 2.3.2 --- For Second Objective --- p.32
Chapter 2.3.3 --- For Third Objective --- p.33
Chapter Chapter 3 --- In vitro Study of Effect of Low Intensity Pulsed Ultrasound on Mesenchymal Stem Cells --- p.34
Chapter 3.1. --- Introduction --- p.35
Chapter 3.2. --- Materials and Methods --- p.36
Chapter 3.2.1. --- Experimental Animal --- p.36
Chapter 3.2.2. --- Materials and Reagents --- p.36
Chapter 3.2.2.1. --- Dulbecco，s Modified Eagle Medium (DMEM) --- p.36
Chapter 3.2.2.2. --- Phosphate Buffered Saline (PBS) --- p.37
Chapter 3.2.2.3. --- Osteogenic Medium (OS) --- p.37
Chapter 3.2.2.4. --- Alkaline Phosphatase (ALP) Buffer --- p.37
Chapter 3.2.2.5. --- ALP Substrate Buffer --- p.38
Chapter 3.2.2.6. --- MTT Stock Solution --- p.38
Chapter 3.2.2.7. --- MTT Working Solution --- p.38
Chapter 3.2.2.8. --- Lysis buffer --- p.38
Chapter 3.2.2.9. --- Alkaline Phosphatase (ALP) Working Reagents --- p.39
Chapter 3.2.3. --- Isolation of Bone Marrow Derived Mesenchymal Stem Cells (BM derived MSCs) --- p.39
Chapter 3.2.4. --- In vitro Low Intensity Pulsed Ultrasound Treatment --- p.40
Chapter 3.2.4.1. --- In vitro LIPUS Devices --- p.40
Chapter 3.2.4.2. --- Treatment Procedure and Experimantal Groupings --- p.40
Chapter 3.2.5. --- Effect of LIPUS on Cell Viability and Osteogenesis in bone marrow derived-MSCs --- p.41
Chapter 3.2.5.1. --- Cell Viability Assay --- p.41
Chapter 3.2.5.2. --- Alkaline Phosphatase (ALP) Enzyme Activity --- p.42
Chapter 3.2.5.3. --- Cell Morphology and Alkaline Phosphatase Cytochemistry --- p.42
Chapter 3.2.6. --- Statistical Analysis --- p.43
Chapter 3.3. --- Results --- p.43
Chapter 3.3.1. --- Morphology --- p.43
Chapter 3.3.2. --- Total Number of Viable Cells --- p.44
Chapter 3.3.3. --- ALP Activity Absorbance --- p.44
Chapter 3.3.4. --- ALP staining --- p.45
Chapter 3.3.5. --- Qualitative Analysis --- p.45
Chapter 3.3.6. --- Quantitative Analysis --- p.46
Chapter 3.4. --- Discussion --- p.46
Chapter 3.4.1. --- LIPUS have No Enhancing Effect on Proliferation of MSCs in Basal Medium Nor Osteogenic Medium --- p.47
Chapter 3.4.2. --- LIPUS Stimulate Proliferation of MSCs in Early Period --- p.49
Chapter 3.4.3. --- LIPUS Further Enhanced Osteogenesis of MSCs in Osteogenic Medium --- p.49
Chapter 3.4.4. --- 10 mins LIPUS treatment for 7 days can positively enhance osteogenic differentiation --- p.50
Chapter 3.4.5. --- Optimum Conditions of LIPUS was Cell Type Dependent --- p.51
Chapter 3.4.6. --- LIPUS Promoted Osteogenesis in MSCs through Accelerated Mineralization --- p.52
Chapter Chapter 4 --- Enhancement of Posterior Spinal Fusion The Effect of Tissue-Engineered MSC and Calcium Phosphate Ceramic composite treated with LIPUS in Vivo --- p.68
Chapter 4.1. --- Introduction --- p.69
Chapter 4.1.1. --- TCP Biomaterials --- p.70
Chapter 4.2. --- Materials and Methods --- p.71
Chapter 4.2.1. --- Materials and Reagents --- p.71
Chapter 4.2.2. --- Preparation of MSC Derived Osteogenic Cells-tricalcium Phosphate Ceramics Composite --- p.73
Chapter 4.2.3. --- Posterior Spinal Fusion Surgery --- p.74
Chapter 4.2.4. --- In vivo LIPUS treatment --- p.75
Chapter 4.2.5. --- Assessment of Fusion Mass --- p.76
Chapter 4.2.6. --- Histology --- p.77
Chapter 4.2.7. --- Statistical Analysis --- p.79
Chapter 4.3. --- Results --- p.79
Chapter 4.3.1. --- Fusion by Manual Palpation --- p.79
Chapter 4.3.2. --- pQCT Analysis --- p.80
Chapter 4.3.3. --- Histological Analysis --- p.81
Chapter 4.4. --- Discussion --- p.85
Chapter 4.4.1. --- Summary of the Findings from Different Assessment Methods --- p.85
Chapter 4.4.2. --- Addition of MSCs to TCP ceramic in Spinal Fusion --- p.87
Chapter 4.4.3. --- The Needs of Differentiated MSC in Spinal Fusion --- p.89
Chapter 4.4.4. --- bFGF Masked the Effect of OS in MSC --- p.91
Chapter 4.4.5. --- LIPUS Enhanced Bone Formation --- p.95
Chapter 4.4.6. --- LIPUS Enhanced Bone Formation through Mineralization --- p.96
Chapter 4.4.7. --- LIPUS Enhanced Spinal Fusion through Bone Remodeling-induced Fusion Mass --- p.97
Chapter 4.4.8. --- LIPUS Enhanced Bone Formation through Endochondral Ossification --- p.99
Chapter Chapter 5 --- In Vivo Monitoring of Spinal Fusion in Animal Model with High-resolution Peripheral Quantitative Computed Tomography-A New Pilot Study --- p.122
Chapter 5.1. --- Introduction --- p.123
Chapter 5.2. --- Materials and Methods --- p.124
Chapter 5.2.1. --- Animal Groupings --- p.124
Chapter 5.2.2. --- Preparation of MSC Derived Osteogenic Cells-tricalcium Phosphate Ceramics Composite --- p.124
Chapter 5.2.3. --- Posterior Spinal Fusion Operation Procedures --- p.125
Chapter 5.2.4. --- LIPUS treatment --- p.125
Chapter 5.2.5. --- High-resolution Peripheral Quantitative Computed Tomography …- --- p.125
Chapter 5.2.6. --- Analysis with HR-pQCT --- p.126
Chapter 5.3. --- Result --- p.128
Chapter 5.3.1. --- Qualitative Observations from HR-pQCT Images --- p.128
Chapter 5.3.2. --- Quantitative Analysis --- p.129
Chapter 5.4. --- Discussion --- p.130
Chapter Chapter 6 --- "Overall Summary, Discussion and Conclusion" --- p.140
Chapter 6.1. --- Overall Summary and Discussion --- p.141
Chapter 6.2. --- Limitations and Further Studies --- p.145
Chapter 6.3. --- Conclusions --- p.147
Chapter 6.4. --- Summary Flowchart of the whole thesis --- p.148
References --- p.153