When we scan image data by ultrasound, we have a little information of displayed scene. For understanding content of the image we try to separate the observed objects of interest from the background. Obtaining information of these objects is called a process called segmentation. This work is focused on the segmentation of ultrasound image sequences using geometric active contours solved by the method of level sets. For better representation is also dealing with image preprocessing. The result is an implementation of segmentation methods on simulated and real data.

This diploma thesis deals with monitoring of persons in an enclosed space. The goal of this thesis is to get acquainted with the issue of indoor localization and the subsequent creation of own solution using the ultrasound technology. Ultrasound technology should eliminate some deficiency of current technologies. The theoretical part includes the overview of some current methods. Last part of the thesis verifies the function of device.

This diploma thesis deals with monitoring of persons in an enclosed space. The goal of this thesis is to get acquainted with the issue of indoor localization and the subsequent creation of own solution using the ultrasound technology. Ultrasound technology should eliminate some deficiency of current technologies. The theoretical part includes the overview of some current methods. Last part of the thesis verifies the function of device.

This master thesis deals with development and construction of ultrasound diagnostical system with USB interface. The main task is to study current usage of A mode ultrasound systems and methods of their construction. Following with own design of A mode ultrasound system with usage of assigned Olympus ultrasound transducer.

Several studies suggest that the use of ultrasound in conjunction with microbubbles (MBs) can induce the lysis of the blood clots through acoustic cavitation and through the production of microjets and microstreaming. However, there is no accordance about the optimal ultrasound parameters that have to be considered in order to achieve the maximum thrombolytic effect, neither a clear agreement about the type of MBs that have to be used. This project had two main goals: the design and optimization of an in-vitro set-up for the study of clot lysis within coronary arteries and its testing with ultrasound in conjunction with two different types of MBs. The MBs considered were the 3MiCRON MBs and the SonoVue MBs. The ultrasound sequence was developed using a programmable ultrasound architecture (Verasonics, Inc) and was tested using commercially available clinical transducers. Using the designed set-up and varying the ultrasound parameters (frequency, pulse length and pulse amplitude) it was possible to study the clot lysis effciency in conjunction with the two types of MBs. For the 3MiCRON MBs no increase in clot lysis was found with the implemented ultrasound parameters, while considering the SonoVue MBs, a 10% increase in clot lysis was found with 10ms long pulse delivered at 50V (peak-to peak value). The obtained set-up had several aspects in common with the real situation of occluded coronary arteries, although some limitations were present and further optimizations are required. Further work is required in order to assess if different combination of ultrasound parameters are able to lead to an increase in clot lysis when delivered with 3MiCRON or SonoVue MBs.

Purpose: Sonography provides a fast, portable, and noninvasive method for patient assessment. However, the benefit of providing real-time ultrasound (US) imaging and fluid quantification shortly after patient arrival has not been explored. The objective of this study was to prospectively validate a US hemoperitoneum scoring system developed at our institution and determine whether sonography can predict a therapeutic operation. Methods: For 12 months, prospective data on all patients undergoing a trauma sonogram were recorded. All sonograms positive for free fluid were given a hemoperitoneum score. The US score was compared with initial systolic blood pressure and base deficit to assess the ability of sonography to predict a therapeutic laparotomy. Results: Forty of 46 patients (87%) with a US score ≥ 3 required a therapeutic laparotomy. Forty-six of 54 patients with a US score < 3 (85%) did not need operative intervention. The sensitivity of sonography was 83% compared with 28% and 49% for systolic blood pressure and base deficit, respectively, in determining the need for therapeutic operation. Conclusion: We conclude that the majority of patients with a score ≥ 3 will need surgery. The US hemoperitoneum scoring system was a better predictor of a therapeutic laparotomy than initial blood pressure and/or base deficit.

Introduction: There are no validated strategies in the teaching of ultrasound as a diagnostic tool in undergraduate medicine students. Given the role that ultrasound plays in the diagnostic capacity of any clinician is currently undeniable, a teaching method is proposed based on the demonstration of the association between the histopathology of a large vessel vasculitis and the characteristic ultrasound finding, known as the «halo sign». Methods: The teaching strategy was imparted by means of a 10-minute video presentation. Twenty-one final-year students from a single medical school participated in a concordance study and a validation test, identifying images corresponding to the halo sign in 120 different cases. The overall sensitivity, specificity and likelihood ratio of the students were also determined. Results: The overall concordance test had a kappa coefficient of 0.749 (SD: 0.11). The kappa concordance was 0.76 with dynamic images, and 0.84 with cross-sectional slices. The overall sensitivity was 89.7%, and the positive predictive value was 92.3%. The likelihood ratio achieved was 7.28. Conclusions: It has been shown that the application of this pedagogical method is useful in teaching the identification of an ultrasound sign to medical students. This study also suggests conditions that could be useful to improve between-observer agreement in both teaching scenarios and multiple observer scientific studies. / Revisión por pares

A complete understanding of high-intensity focused ultrasound-induced temperature changes in tissue requires insight into all potential mechanisms for heat deposition. Applications of therapeutic ultrasound often utilize acoustic pressures capable of producing cavitation activity. Recognizing the ability of bubbles to transfer acoustic energy into heat generation, a study of the role bubbles play in tissue hyperthermia becomes necessary. These bubbles are typically less than 50μm. This dissertation examines the contribution of bubbles and their motion to an enhanced heating effect observed in a tissue-mimicking phantom. A series of experiments established a relationship between bubble activity and an enhanced temperature rise in the phantom by simultaneously measuring both the temperature change and acoustic emissions from bubbles. It was found that a strong correlation exists between the onset of the enhanced heating effect and observable cavitation activity. In addition, the likelihood of observing the enhanced heating effect was largely unaffected by the insonation duration for all but the shortest of insonation times, 0.1 seconds. Numerical simulations were used investigate the relative importance of two candidate mechanisms for heat deposition from bubbles as a means to quantify the number of bubbles required to produce the enhanced temperature rise. The energy deposition from viscous dissipation and the absorption of radiated sound from bubbles were considered as a function of the bubble size and the viscosity of the surrounding medium. Although both mechanisms were capable of producing the level of energy required for the enhanced heating effect, it was found that inertial cavitation, associated with high acoustic radiation and low viscous dissipation, coincided with the the nature of the cavitation best detected by the experimental system. The number of bubbles required to account for the enhanced heating effect was determined through the numerical study to be on the order of 150 or less.

Orientador: Antonio Cesar Germano Martins / Resumo: A germinação é uma sequência ordenada de atividades metabólicas, que se inicia com a embebição e culmina na protrusão da radícula dos envoltórios da semente. Estudar esse processo é extremamente importante para produção de mudas, que poderão entre outras aplicações serem utilizadas na revegetação de áreas degradadas. Para o processo de germinação são necessários alguns fatores externos, como luz, água e oxigênio. A presença desses fatores é de grande importância para formação de plântulas normais. Algumas espécies são consideradas dormentes, por adotarem uma estratégia de sobrevivência para superar condições ambientais adversas. Para essas espécies a germinação não acontece mesmo quando as sementes são viáveis. Essas sementes germinam apenas quando esse processo é interrompido, o que pode ocorrer naturalmente quando as condições tornam-se mais favoráveis para a sobrevivência da espécie ou de forma induzida. Estudos demonstram que o ultrassom pode aumentar a taxa de germinação, no entanto, uma aplicação de dosagem excessiva pode causar danos graves à semente, impossibilitando a germinação. O presente trabalho teve objetivo estudar a quebra da dormência pela aplicação de ondas ultrassônicas de baixa frequência e avaliar o seu efeito sobre a germinação de sementes de Senna multijuga (Rich.) H. S. Irwin & Barneby, espécie utilizada na revegetação de áreas degradadas. Embora o ultrassom possua muitas aplicações, o seu uso para a quebra de dormência é ainda uma área pouco explorada... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

Bacterial pathogens on the surfaces of raw produce may be difficult to remove for identification and enumeration. The first part of this project examined whether ultrasonic treatment (40 kHz) of a rinse solution would enhance recovery of Salmonella spp. from various produce surfaces. Strawberries, apples, and cantaloupe were surface inoculated with a five-strain cocktail of nalidixic acid resistant Salmonella spp. Samples were subjected to one of six different treatments using different combinations of agitation methods (manual shaking or ultrasound), diluent temperatures (25°C and 40°C), and agitation times (60 and 120 seconds). After treatment, diluent was spiral plated onto tryptic soy agar supplemented with 50 ppm of nalidixic acid and plates were incubated at 37°C for 48 hours. Results from this study indicate that ultrasonic treatment of a rinse solution did not enhance or diminish recovery of Salmonella spp. from produce surfaces, as compared to manual agitation. The effects of diluent temperature and exposure time appeared to have a significant effect on recovery, depending on the type of produce. The second part of this project used a computer imaging system to determine the surface area of various types of produce. The imaging system acquired and stored multiple images of the produce samples. From these images, surface fitting and approximation of a 3-D wire frame model were used to calculate surface area. From these measurements, it was determined that there were statistical relationships between surface area and weight. Surface area measurements were used to develop equations to predict surface area from weight measurements. / Master of Science