Navegando por Palavras-chave "Relaxometry"

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    Desenvolvimento de uma ferramenta para auxílio na avaliação de lesões cartilaginosas do joelho
    (Universidade Federal de São Paulo (UNIFESP), 2017-09-26) Jornada, Tiago da Silva [UNIFESP]; Medeiros, Regina Bitelli [UNIFESP]; http://lattes.cnpq.br/2665030032263086; http://lattes.cnpq.br/0215509361949183; Universidade Federal de São Paulo (UNIFESP)
    Introduction: T2 maps are commonly used in the evaluation and diagnosis of cartilaginous regions of the knee. When cartilage is preserved, collagen impairs the mobility of water, resulting in a lower T2 value when compared to that of non-preserved cartilage. However, when this structure is weakened, the water flow is higher, causing an increase in the values ​​for T2. In this way, the T2 maps present the analysis of the cartilage content in an indirect way, through Magnetic Resonance Imaging (MRI). However, for the study of T2 relaxometry it is necessary to acquire an MRI with single-echo or multi-echo protocols and post-process it with specific software. The main obstacle is that the programs available on the market require a high financial investment. Objective: To develop software that provides T2 Maps. Methods: By means of magnetic resonance imaging of 1.5 T, we obtained MRI from seven patients and developed software in MATLAB to generate T2 maps. Finally, we compare the results obtained with three free programs that have the same purpose. Results: We developed software and named it T2 Maps. We compared the results obtained with three free programs, however, two of them did not allow a more careful analysis of the cartilaginous regions of the knee. In contrast, when the comparative study was possible, there was no significant difference between the values ​​of the T2 maps. Conclusion: The objective proposed in this paper was reached. The software that will be made available to the academic and professional environment allows us to generate the T2 maps of the cartilaginous structures of the knee in an agile way, with usability features that differentiate it from the other programs tested in the present study.
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    Image evaluation of HIV encephalopathy: a multimodal approach using quantitative MR techniques
    (Springer, 2011-11-01) Prado, Paulo T. C.; Escorsi-Rosset, Sara; Cervi, Maria C.; Santos, Antonio Carlos; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP)
    Introduction A multimodal approach of the human immunodeficiency virus (HIV) encephalopathy using quantitative magnetic resonance (MR) techniques can demonstrate brain changes not detectable only with conventional magnetic resonance imaging (MRI). the aim of this study was to compare conventional MRI and MR quantitative techniques, such as magnetic resonance spectroscopy (MRS) and relaxometry and to determine whether quantitative techniques are more sensitive than conventional imaging for brain changes caused by HIV infection.Methods We studied prospectively nine HIV positive children (mean age 6 years, from 5 to 8 years old) and nine controls (mean age 7.3 years; from 3 to 10 years), using MRS and relaxometry. Examinations were carried on 1.5-T equipment.Results HIV-positive patients presented with only minor findings and all control patients had normal conventional MR findings. MRS findings showed an increase in choline to creatine (CHO/CRE) ratios bilaterally in both frontal gray and white matter, in the left parietal white matter, and in total CHO/CRE ratio. in contrast, N-acetylaspartate to creatine (NAA/CRE) ratios did not present with any significant difference between both groups. Relaxometry showed significant bilateral abnormalities, with lengthening of the relaxation time in HIV positive in many regions.Conclusion Conventional MRI is not sensitive for early brain changes caused by HIV infection. Quantitative techniques such as MRS and relaxometry appear as valuable tools in the diagnosis of these early changes. Therefore, a multimodal quantitative study can be useful in demonstrating and understanding the physiopathology of the disease.