989 resultados para B-mode
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Pós-graduação em Biotecnologia Animal - FMVZ
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Degeneration of tendon tissue is a common cause of tendon dysfunction with the symptoms of repeated episodes of pain and palpable increase of tendon thickness. Tendon mechanical properties are directly related to its physiological composition and the structural organization of the interior collagen fibers which could be altered by tendon degeneration due to overuse or injury. Thus, measuring mechanical properties of tendon tissue may represent a quantitative measurement of pain, reduced function, and tissue health. Ultrasound elasticity imaging has been developed in the last two decades and has proved to be a promising tool for tissue elasticity imaging. To date, however, well established protocols of tendinopathy elasticity imaging for diagnosing tendon degeneration in early stages or late stages do not exist. This thesis describes the re-creation of one dynamic ultrasound elasticity imaging method and the development of an ultrasound transient shear wave elasticity imaging platform for tendon and other musculoskeletal tissue imaging. An experimental mechanical stage with proper supporting systems and accurate translating stages was designed and made. A variety of high-quality tissue-mimicking phantoms were made to simulate homogeneous and heterogeneous soft tissues as well as tendon tissues. A series of data acquisition and data processing programs were developed to collect the displacement data from the phantom and calculate the shear modulus and Young’s modulus of the target. The imaging platform was found to be capable of conducting comparative measurements of the elastic parameters of the phantoms and quantitatively mapping elasticity onto ultrasound B-Mode images. This suggests the system has great potential for not only benefiting individuals with tendinopathy with an earlier detection, intervention and better rehabilitation, but also for providing a medical tool for quantification of musculoskeletal tissue dysfunction in other regions of the body such as the shoulder, elbow and knee.
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Ultrasonography has an inherent noise pattern, called speckle, which is known to hamper object recognition for both humans and computers. Speckle noise is produced by the mutual interference of a set of scattered wavefronts. Depending on the phase of the wavefronts, the interference may be constructive or destructive, which results in brighter or darker pixels, respectively. We propose a filter that minimizes noise fluctuation while simultaneously preserving local gray level information. It is based on steps to attenuate the destructive and constructive interference present in ultrasound images. This filter, called interference-based speckle filter followed by anisotropic diffusion (ISFAD), was developed to remove speckle texture from B-mode ultrasound images, while preserving the edges and the gray level of the region. The ISFAD performance was compared with 10 other filters. The evaluation was based on their application to images simulated by Field II (developed by Jensen et al.) and the proposed filter presented the greatest structural similarity, 0.95. Functional improvement of the segmentation task was also measured, comparing rates of true positive, false positive and accuracy. Using three different segmentation techniques, ISFAD also presented the best accuracy rate (greater than 90% for structures with well-defined borders). (E-mail: fernando.okara@gmail.com) (C) 2012 World Federation for Ultrasound in Medicine & Biology.
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Abstract Background To establish the correlation between quantitative analysis based on B-mode ultrasound images of vulnerable carotid plaque and histological examination of the surgically removed plaque, on the basis of a videodensitometric digital texture characterization. Methods Twenty-five patients (18 males, mean age 67 ± 6.9 years) admitted for carotid endarterectomy for extracranial high-grade internal carotid artery stenosis (≥ 70% luminal narrowing) underwent to quantitative ultrasonic tissue characterization of carotid plaque before surgery. A computer software (Carotid Plaque Analysis Software) was developed to perform the videodensitometric analysis. The patients were divided into 2 groups according to symptomatology (group I, 15 symptomatic patients; and group II, 10 patients asymptomatic). Tissue specimens were analysed for lipid, fibromuscular tissue and calcium. Results The first order statistic parameter mean gray level was able to distinguish the groups I and II (p = 0.04). The second order parameter energy also was able to distinguish the groups (p = 0,02). A histological correlation showed a tendency of mean gray level to have progressively greater values from specimens with < 50% to >75% of fibrosis. Conclusion Videodensitometric computer analysis of scan images may be used to identify vulnerable and potentially unstable lipid-rich carotid plaques, which are less echogenic in density than stable or asymptomatic, more densely fibrotic plaques.
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Lo scopo dello studio è quello di valutare il comportamento all’ecografia B mode e con mezzo di contrasto delle metastasi epatiche da tumore neuroendocrino ed individuare eventuali peculiarità in base alla sede del tumore primitivo, al tipo istologico, al grado di differenziazione, al Ki 67 ed al tipo di marcatore bioumorale.
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Il Sorafenib è l’unica terapia sistemica approvata per l’epatocarcinoma (HCC) avanzato. Tuttavia, molti tumori sviluppano resistenze. La chemioterapia metronomica sembrerebbe avere un effetto antiangiogenetico. La Capecitabina metronomica è potenzialmente efficace nell’HCC avanzato. Lo scopo dello studio è stato valutare il comportamento di un modello murino di HCC sottoposto a Sorafenib, Capecitabina e terapia combinata, per dimostrarne un eventuale effetto sinergico. Il modello è stato creato in topi scid mediante inoculazione sottocutanea di 5 milioni di cellule HuH7. I topi sono stati suddivisi in 4 gruppi: gruppo 1 sottoposto a terapia con placebo (9 topi), gruppo 2 a Sorafenib (7 topi), gruppo 3 a Capecitabina (7 topi) e gruppo 4 a terapia combinata Sorafenib+Capecitabina (10 topi). I topi sono stati studiati al giorno 0 e 14 con ecografia B-mode e con mezzo di contrasto (CEUS). Al giorno 14 sono stati sacrificati e i pezzi tumorali sono stati conservati per l’analisi Western Blot. Un topo del gruppo 1 e 4 topi del gruppo 4 sono morti precocemente e quindi sono stati esclusi. Il delta di crescita tumorale al giorno 14 rispetto al giorno 0 è risultato di +503 %, +158 %, +462 % e +176 % rispettivamente nei 4 gruppi (p<0.05 tra i 4 gruppi, tra il gruppo 1 e 2, tra il gruppo 1 e 4, tra il gruppo 2 e 3, tra il gruppo 3 e 4). Alla CEUS non si sono evidenziate differenze statisticamente significative nei cambiamenti di perfusione tumorale al giorno 14 nei 4 gruppi. L’analisi Western Blot ha mostrato livelli di VEGFR-2 inferiori nel gruppo dei topi trattati con Sorafenib. La terapia di associazione di Sorafenib e Capecitabina non comporta un beneficio, in termini di riduzione della crescita tumorale, in un modello murino di HCC rispetto al solo Sorafenib. Inoltre, può essere sospettato un incremento di tossicità.
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In the field of computer assisted orthopedic surgery (CAOS) the anterior pelvic plane (APP) is a common concept to determine the pelvic orientation by digitizing distinct pelvic landmarks. As percutaneous palpation is - especially for obese patients - known to be error-prone, B-mode ultrasound (US) imaging could provide an alternative means. Several concepts of using ultrasound imaging to determine the APP landmarks have been introduced. In this paper we present a novel technique, which uses local patch statistical shape models (SSMs) and a hierarchical speed of sound compensation strategy for an accurate determination of the APP. These patches are independently matched and instantiated with respect to associated point clouds derived from the acquired ultrasound images. Potential inaccuracies due to the assumption of a constant speed of sound are compensated by an extended reconstruction scheme. We validated our method with in-vitro studies using a plastic bone covered with a soft-tissue simulation phantom and with a preliminary cadaver trial.