Volume 10, Number 2, April/June 2012

Principal Component Analysis applied to digital image compression

Rafael do Espírito Santo

DOI: 10.1590/S1679-45082012000200004

Objective:To describe the use of a statistical tool (Principal Component Analysis – PCA) for the recognition of patterns and compression, applying these concepts to digital images used in Medicine.METHODS:The description of Principal Component Analysis is made by means of the explanation of eigenvalues and eigenvectors of a matrix. This concept is presented on a digital image collected in the clinical routine of a hospital, based on the functional aspects of a matrix. The analysis of potential for recovery of the […]

Spectral characteristics of the hippocampal LFP during contextual fear conditioning

Birajara Soares Machado, Ana Carolina Bione Kunicki, Edgard Morya, Koichi Sameshima

DOI: 10.1590/S1679-45082012000200005

Objective:The hippocampus has an important role in the acquisition and recall of aversive memories. The objective of this study was to investigate the relationship among hippocampal rhythms.METHODS:Microeletrodes arrays were implanted in the hippocampus of Wistar rats. The animals were trained and tested in a contextual fear conditioning task. The training consisted in applying shocks in the legs. The memory test was performed 1 day (recent memory) or 18 days (remote memory) after training. We proposed a measure based on the […]

Ultrastructural transneuronal degeneration study of axonal elements within the paratrigeminal nucleus in sinoaortic deafferented rats

Cristofer André Caous, Ricardo Luís Smith, Edna Freymuller Haapalainen, Charles Julian Lindsey

DOI: 10.1590/S1679-45082012000200006

Objective:Morphological study that searched to authenticate the presence of sinoaortic baroreceptor inputs within the dorsolateral medullary nucleus under electron microscopy analysis.METHODS:After a 5-day survival period, 9 baroreceptor-denervated rats deeply anaesthetized with equithesin were transcardially perfused and their brains were histologically processed.RESULTS:The neuronal cytoarchitecture of the paratrigeminal nucleus comprehends afferent projections from other nuclei that have a distributive character regarding visceral and nociceptive functions in the cardiovascular reflex integration response.CONCLUSION:The medial portion of the nucleus receives afferent projections of the rostral […]

Seeking tools for image fusion between computed tomography, structural and functional magnetic resonance methods for applications in neurosurgery

Liana Guerra Sanches da Rocha, Edson Amaro Junior

DOI: 10.1590/S1679-45082012000200007

Objective:To evaluate tools for the fusion of images generated by tomography and structural and functional magnetic resonance imaging.METHODS:Magnetic resonance and functional magnetic resonance imaging were performed while a volunteer who had previously undergone cranial tomography performed motor and somatosensory tasks in a 3-Tesla scanner. Image data were analyzed with different programs, and the results were compared.RESULTS:We constructed a flow chart of computational processes that allowed measurement of the spatial congruence between the methods. There was no single computational tool that […]

Computerized brain tumor segmentation in magnetic resonance imaging

Maryana de Carvalho Alegro, Edson Amaro Junior, Rosei de Deus Lopes

DOI: 10.1590/S1679-45082012000200008

Objective:To propose an automatic brain tumor segmentation system.METHODS:The system used texture characteristics as its main source of information for segmentation.RESULTS:The mean correct match was 94% of correspondence between the segmented areas and ground truth.CONCLUSION:Final results showed that the proposed system was able to find and delimit tumor areas without requiring any user interaction.

In vivo magnetic resonance imaging tracking of C6 glioma cells labeled with superparamagnetic iron oxide nanoparticles

Javier Bustamante Mamani, Jackeline Moraes Malheiros, Ellison Fernando Cardoso, Alberto Tannús, Paulo Henrique Silveira, Lionel Fernel Gamarra

DOI: 10.1590/S1679-45082012000200009

Objective:The aim of the current study was to monitor the migration of superparamagnetic iron oxide nanoparticle (SPION)-labeled C6 cells, which were used to induce glioblastoma tumor growth in an animal model, over time using magnetic resonance imaging (MRI), with the goal of aiding in tumor prognosis and therapy.METHODS:Two groups of male Wistar rats were used for the tumor induction model. In the first group (n=3), the tumors were induced via the injection of SPION-labeled C6 cells. In the second group […]

Levodopa versus non-levodopa brain language fMRI in Parkinson’s disease

Paula Ricci Arantes, Heloise Helena Gobato, Bárbara Bordegatto Davoglio, Maria Ângela Maramaldo Barreiros, André Carvalho Felício, Orlando Graziani Povoas Barsottini, [...]

DOI: 10.1590/S1679-45082012000200010

Objective:To identify the effect of levodopa in language areas in Parkinson’s disease patients.METHODS:We evaluated 50 patients with mild to moderate Parkinson’s disease, age and gender paired to 47 healthy volunteers. We selected two homogeneous groups of 18 patients taking levodopa and 7 no levodopa patients. The functional magnetic resonance imaging verbal fluency task, with low and high cognitive demands, was performed at a 3T magnetic resonance imaging equipment. Data was analyzed with XBAM software for group maps and ANOVA comparison.RESULTS:Patients […]

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