Résumé
PURPOSE: The purpose of this study was to evaluate the accuracy of an active contour model for estimating the posterior ablative margin in images obtained by the fusion of real-time ultrasonography (US) and 3-dimensional (3D) US or magnetic resonance (MR) images of an experimental tumor model for radiofrequency ablation. METHODS: Chickpeas (n=12) and bovine rump meat (n=12) were used as an experimental tumor model. Grayscale 3D US and T1-weighted MR images were pre-acquired for use as reference datasets. US and MR/3D US fusion was performed for one group (n=4), and US and 3D US fusion only (n=8) was performed for the other group. Half of the models in each group were completely ablated, while the other half were incompletely ablated. Hyperechoic ablation areas were extracted using an active contour model from real-time US images, and the posterior margin of the ablation zone was estimated from the anterior margin. After the experiments, the ablated pieces of bovine rump meat were cut along the electrode path and the cut planes were photographed. The US images with the estimated posterior margin were compared with the photographs and post-ablation MR images. The extracted contours of the ablation zones from 12 US fusion videos and post-ablation MR images were also matched. RESULTS: In the four models fused under real-time US with MR/3D US, compression from the transducer and the insertion of an electrode resulted in misregistration between the real-time US and MR images, making the estimation of the ablation zones less accurate than was achieved through fusion between real-time US and 3D US. Eight of the 12 post-ablation 3D US images were graded as good when compared with the sectioned specimens, and 10 of the 12 were graded as good in a comparison with nicotinamide adenine dinucleotide staining and histopathologic results. CONCLUSION: Estimating the posterior ablative margin using an active contour model is a feasible way of predicting the ablation area, and US/3D US fusion was more accurate than US/MR fusion.
Sujets)
Techniques d'ablation , Ablation par cathéter , Cicer , Ensemble de données , Électrodes , Viande , NAD , , Transducteurs , ÉchographieRésumé
RESUMO: este artigo tem como foco a aplicabilidade da técnica de sombreamento na pesquisa sobre acessibilidade em uma instituição de ensino superior brasileira. No Brasil, esta técnica é ainda pouco conhecida, aplicada e disseminada apesar de sua relevância por alocar o pesquisador sombra dentro da rotina diária do participante. Neste estudo, apresentamos a aplicabilidade da técnica de sombreamento no cotidiano acadêmico de um estudante cego. Os resultados indicam que esta técnica (a) situa o investigador dentro da experiência de vida real do participante, aproximando pesquisadores sem deficiência da realidade vivida pelas pessoas com deficiência; (b) a técnica clarifica e amplia o conceito de acessibilidade na prática porque cruza o discurso oficial ou política de inclusão com aquilo que acontece no ambiente, isto é, a voz da pessoa com deficiência ganha destaque porque é ela que indica o que é ou não acessível; (c) joga o pesquisador dentro de micro-espaços (como sala de aula, refeitórios) que são lugares onde ocorrem relações de poder geradoras de barreiras para aqueles com deficiência e (d) favorece a identificação de barreiras cotidianas e, portanto, contribui para o desenvolvimento de políticas institucionais de acessibilidade que auxiliam na diminuição e eliminação dos obstáculos na trajetória universitária de estudantes com deficiência. Conclui-se que a técnica de sombreamento, aplicada ao processo de coleta de dados e produção de conhecimentos com e sobre pessoas com deficiência, contribui para o desenvolvimento de metodologias de pesquisa inovadoras no campo da Educação Especial, Inclusão em Educação e Estudos sobre a Deficiência.
ABSTRACT: This paper focuses on the application of the technique Shadowing in a research on accessibility in a Brazilian higher education institution. In Brazil, this technique is still little known, little applied and disseminated despite its relevance for allocating the 'shadow researcher' within the participant's daily routine. In this paper we present the application of the technique Shadowing during an academic day of a blind university student. Results show that Shadowing (a) places the researcher within the participant's real life experiences, hence approximating researchers without disabilities to the reality experienced by persons with disabilities; (b) it clarifies and broadens the concept of accessibility in practice as it allows interlacing official discourse or inclusion policies and what really happens in the environment, that is, the person with disability's voice stands out because he/she indicates what is or what is not accessible; (c) it 'throws' the researcher within micro-spaces, such as classroom and cafeteria, where power relations occur generating barriers for those with disabilities, and (d) it helps the identification of daily barriers and, therefore, contributes to the development of institutional policy that supports the reduction/elimination of obstacles in the university trajectory of students with disability. This paper concludes that Shadowing applied to the process of data collection and knowledge production with and on persons with disabilities contributes to the development of research methodology innovation in studies in the field of Special Education, School Inclusion, and Studies on Disability.
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Objective To study the shadowing effect when using UWB bio-radar to detect multiple static human targets to solve the problem in multi-target detection.Methods With simulated breathing apparatus as detection targets,the UWB bioradar multi static targets respiration detection experiment was designed,and the influences of distance and angle between targets and its respiratory frequency and amplitude on the shadowing effect were studied.Result The shadowing effect was mainly affected by the relative position of the multiple targets,while the respiratory frequency and amplitude of the target had less influence on it.Conclusion When multi static human targets are detected the shadowing effect does exist,and the effect mainly derives from the block of electromagnetic wave by the front target,while the change of respiratory parameters of the front target has little influence on the effect.
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MicroRNAs (miRNAs) constitute an extensive class of non coding, gene regulating RNAs. Till date, there are no detailed reports of miRNAs in Zebra finch (Taeniopygia guttata). Here we adopt the method of homology search for the identification of miRNAs in T. guttata by using the pre-miRNAs of all known vertebrates. We report 221 miRNAs, of which 46 miRNAs are having 100% identity to pre miRNA and 208 miRNA to mature sequences. 104 sequences have mismatches at pre-miRNA level but have conserved mature miRNA. Thus the functions of mature sequences have been conserved during evolution of T. guttata genome. We also find that 157 miRNAs are closer to Gallus gallus, which is expected. Of which 117 sequences do not have 100% identity at pre-miRNA level. More importantly we find that 23 miRNAs come from platypus giving a remarkable clue to their relation with avian members. We also report conservation of 10 miRNA clusters. Five of these clusters are conserved with G. gallus, while the other 5 are altered with respect to gene orientation in the genome of T. guttata, and one among them is repositioned to chromosome 4a in T. guttata. These 5 altered gene orientations are unique to T. guttata genome and could have arisen due to divergence during evolution.
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A breast lesion with posterior acoustic shadowing is often encountered on sonography and this finding is generally accepted as a sign of malignancy. Although its detection is important for differentiating a malignant breast mass from a benign breast mass, posterior acoustic shadowing is the result of attenuation of the sound beam by a desmoplastic host response to breast cancer rather than the posterior acoustic shadowing being due to the tumor itself. Therefore, many breast conditions that contain fibrous elements also can induce some degree of acoustic shadowing. In this article, we present various benign breast lesions that display posterior acoustic shadowing and we discuss the radiologic findings along with the pathologic correlation.