Browsing by Author "Nunes, R"
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- Dynamics of Epileptic Activity in a Peculiar Case of Childhood Absence Epilepsy and Correlation with Thalamic Levels of GABAPublication . Leal, A; Vieira, JP; Lopes, R; Nunes, R; Gonçalves, S; Lopes da Silva, F; Figueiredo, PChildhood absence epilepsy (CAE) is a syndrome with well-defined electroclinical features but unknown pathological basis. An increased thalamic tonic GABA inhibition has recently been discovered on animal models (Cope et al., 2009), but its relevance for human CAE is unproven. METHODS: We studied an 11-year-old boy, presenting the typical clinical features of CAE, but spike-wave discharges (SWD) restricted to one hemisphere. RESULTS: High-resolution EEG failed to demonstrate independent contralateral hemisphere epileptic activity. Consistently, simultaneous EEG-fMRI revealed the typical thalamic BOLD activation, associated with caudate and default mode network deactivation, but restricted to the hemisphere with SWD. Cortical BOLD activations were localized on the ipsilateral pars transverse. Magnetic resonance spectroscopy, using MEGA-PRESS, showed that the GABA/creatine ratio was 2.6 times higher in the hemisphere with SWD than in the unaffected one, reflecting a higher GABA concentration. Similar comparisons for the patient's occipital cortex and thalamus of a healthy volunteer yielded asymmetries below 25%. SIGNIFICANCE: In a clinical case of CAE with EEG and fMRI-BOLD manifestations restricted to one hemisphere, we found an associated increase in thalamic GABA concentration consistent with a role for this abnormality in human CAE.
- Osteomielite Xantogranulomatosa do ÚmeroPublication . Nunes, R; Costa, J; Martins, MOs autores apresentam um caso de lesão osteolítica da metáfise distal do úmero em que o exame anatomopatológico permitiu estabelecer o diagnóstico de osteomielite xantogranulomatosa. Esta entidade nosológica pouco frequente, que pode mimetizar patologia óssea tumoral, é uma forma de osteomielite crónica caracterizada histologicamente pela acumulação de histiócitos vacuolizados e de células inflamatórias. Os autores descrevem neste artigo a histopatologia deste tipo de osteomielite e discutem o seu diagnóstico diferencial.
- Reconstruction of White Matter Fibre Tracts Using Diffusion Kurtosis Tensor Imaging at 1.5T: Pre-Surgical Planning in Patients with GliomasPublication . Leote, J; Nunes, R; Cerqueira, L; Loução, R; Ferreira, HTractography studies for pre-surgical planning of primary brain tumors is typically done using diffusion tensor imaging (DTI), which cannot resolve crossing, kissing or highly angulated fibres. Tractography based on the estimation of the diffusion kurtosis (DK) tensor was recently demonstrated to enable tackling these limitations. However, its use in the clinical context at low 1.5T field has not yet been reported. PURPOSE: To evaluate if the estimation of whole-brain tractography using the DK tensor is feasible for pre-surgical investigation of patients with brain tumors at 1.5T. METHODS: Eight healthy subjects and 3 patients with brain tumors were scanned at 1.5T using a 12-channel head coil. Diffusion-weighted images were acquired with repetition/echo times of 5800/107 ms, 82 × 82 resolution, 3 × 3 × 3 mm3 voxel size, b-values of 0, 1000, 2000 s/mm2 and 64 gradient sensitising directions. Whole-brain tractography was estimated using the DK tensor and corticospinal tracts (CST) were isolated using regions-of-interest placed at the cerebral peduncles and motor gyrus. Tract size, DK metrics and CST deviation index (highest curvature point) were compared between healthy subjects and patients. RESULTS: Tract sizes did not differ between groups. The CST deviation index was significantly higher in patients compared to healthy subjects. Fractional anisotropy was significantly lower in patients, with higher mean kurtosis asymmetry index at the highest curvature point in patients. CONCLUSIONS: Corticospinal fibre bundles estimated using DK tensor in a 1.5T scanner presented similar properties in patients with brain gliomas as those reported in the literature using DTI-based tractography.
- A Relação Entre a Mente e o CorpoPublication . Pinote Bernardes, S; Nunes, R; Carvalho, J; Azevedo, I