922 resultados para resonancia magnética


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BACKGROUND: Ultrasonography (US), Computed Tomography (CT), and Magnetic Resonance imaging (MR) were compared for the staging of renal tumors. The differences between these imaging techniques were also studied for their ability to detect adenopathies, vascular invasion, distant intra-abdominal metastases, and particularly adjacent organ invasion. METHODS: Thirty-one patients with solid or complex renal masses were prospectively studied using US, CT, and MR. Differences between the results obtained were studied using the COCHRAN G test and the McNEMAR test. The sensitivity and specificity of each diagnostic technique were compared against a gold standard of the surgical and histopathological findings. RESULTS: The following sensitivities were obtained: For the detection of adenopathy, US 63.6%, CT and MR 90.9%. For vascular invasion, US 42.8%, CT and MR 85.7%. For the adjacent organ invasion, US 28.5%, CT 85.7%, and MR 71.4%. Some of the criteria that suggest invasion of adjacent structures include: the envelopment of the adjacent structures by the tumor, tumor extension into the adjacent structures with an irregular appearance, and alterations in shape, size, and density of adjacent structures. Loss of fat planes between the tumor and adjacent structures is not a sign of tumor invasion. CONCLUSIONS: Significant differences were found in the detection capacity of US in relation to CT and MR, which were similar. All three techniques were highly sensitive and specific only in the detection of distant abdominal metastases. In addition to the accuracy of these diagnostic modalities for the detection and staging of tumors, invasiveness, risks and cost should be considered in relation to relative costs and benefits.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The objective of this work was to evaluate the magnetic susceptibility efficiency for estimating the support capacity of areas for vinasse application. Two hundred forty-one soil samples were collected from a 380-ha area, on which soil chemical properties, clay content, and magnetic susceptibility were determined. Vinasse requirement was calculated for each sample. Data were subjected to descriptive statistical analysis, and regression models were developed between magnetic susceptibility and the other evaluated attributes. The analysis of data spatial dependence was performed using geostatistics. Kriging maps and cross variograms were built in order to investigate the spatial correlation between soil magnetic susceptibility and studied attributes. Based on the map of vinasse requirement, on the soil classes, and on the kriging map, calculations were done for average vinasse dose and average soil support capacity, weighted by the area. Magnetic susceptibility has significant linear spatial correlation with recommended vinasse doses and soil support capacity for the application of this effluent, and it can be used as a pedotransfer function for indirect quantification of soil support capacity.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Biologia Geral e Aplicada - IBB

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Agronomia (Produção Vegetal) - FCAV

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Agronomia (Produção Vegetal) - FCAV

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Pós-graduação em Agronomia (Ciência do Solo) - FCAV

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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)