Browsing by Author "Ribeiro, Eduardo"
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- Amygdala activation in response to 2D and 3D emotion-inducing stimuliPublication . Dores, Artemisa Rocha; Barbosa, Fernando; Monteiro, Luís; Leitão, Miguel; Reis, Mafalda; Coelho, Carlos M.; Ribeiro, Eduardo; Carvalho, Irene P.; Sousa, Liliana; Castro-Caldas, AlexandreStudying changes in brain activation according to the valence of emotion-inducing stimuli is essential in the research on emotions. Due to the ecological potential of virtual reality, it is also important to examine whether brain activation in response to emotional stimuli can be modulated by the three-dimensional (3D) properties of the images. This study uses functional Magnetic Resonance Imaging to compare differences between 3D and standard (2D) visual stimuli in the activation of emotion-related brain areas. The stimuli were organized in three virtual-reality scenarios, each with a different emotional valence (pleasant, unpleasant and neutral). The scenarios were presented in a pseudo-randomized order in the two visualization modes to twelve healthy males. Data were analyzed through a GLM-based fixed effects procedure. Unpleasant and neutral stimuli activated the right amygdala more strongly when presented in 3D than in 2D. These results suggest that 3D stimuli, when used as “building blocks” for virtual environments, can induce increased emotional loading, as shown here through neuroimaging.
- Apparent diffusion coefficient in the analysis of prostate cancerPublication . Adubeiro, Nuno; Nogueira, Luísa; Ribeiro, Eduardo; Alves, Sandra; Ferreira, Hugo; La Fuente, JoséThe multiparametric magnetic resonance imaging (MPMRI) approach, has allowed the diagnostic performance in the detection and characterization of prostate cancer (PCa). Diffusion-weighted imaging (DWI), is an important technique in the MPMRI, that provides qualitative and quantitative biological information regarding water diffusivity in a non-invasive manner. The apparent diffusion coefficient (ADC) measures water mobility and can be quantified from the signal intensity loss between two or more b-values. Different studies reported that ADC values are directly associated with microvessel density and cellularity. One of the main aspects that is in discussion is the b-values that must be used in the DWI sequence in order to compute ADC.
- Apparent diffusion coefficient in the analysis of prostate cancer: determination of optimal b-value pair to differentiate normal from malignant tissuePublication . Adubeiro, Nuno; Nogueira, Maria Luísa; Nunes, Rita G.; Ferreira, Hugo Alexandre; Ribeiro, Eduardo; La Fuente, José Maria FerreiraPurpose Determining optimal b-value pair for differentiation between normal and prostate cancer (PCa) tissues. Methods Forty-three patients with diagnosis or PCa symptoms were included. Apparent diffusion coefficient (ADC) was estimated using minimum and maximum b-values of 0, 50, 100, 150, 200, 500 s/mm2 and 500, 800, 1100, 1400, 1700 and 2000s/mm2, respectively. Diagnostic performances were evaluated when Area-under-the-curve (AUC) > 95%. Results 15 of the 35 b-values pair surpassed this AUC threshold. The pair (50, 2000 s/mm2) provided the highest AUC (96%) with ADC cutoff 0.89 × 10–3 mm2/s, sensitivity 95.5%, specificity 93.2% and accuracy 94.4%. Conclusions The best b-value pair was b = 50, 2000 s/mm2.
- Avanços da ressonância magnética mamária no diagnóstico do carcinoma da mamaPublication . Costa, Didier; Nogueira, Luísa; Ribeiro, EduardoA Ressonância Magnética Mamaria (RMM), ao longo da década, tem demonstrado um franco desenvolvimento no diagnóstico e caracterização do Carcinoma Mamário. O objectivo deste trabalho científico é demonstrar, através de uma revisão bibliográfica, os avanços desta modalidade na avaliação das lesões da mama, tendo em conta as características: elasticidade (Elastografia), bioquímicas (Espectroscopia), celularidade (Difusão) e vascularização (Perfusão). A avaliação destas em consonância com as morfológicas e cinéticas (RMM), permitem um aumento da especificidade da RMM, reduzindo assim o número de biopsias desnecessárias. Contudo estas evoluções técnicas devem estar em consonância com a inovação em questões de software de processamento de Imagem e hardware dos equipamentos de Ressonância Magnética.
- Protocolos para estudo do Sistema OsteoarticularPublication . Ribeiro, EduardoO desenvolvimento de novas técnicas imagiológicas, nomeadamente da TC e da RM, veio possibilitar uma maior precisão no diagnóstico, grau e classificação das lesões tumorais, sendo atualmente estes os métodos imagiológicos mais utilizados.