Extratemporal abnormalities in phosphorus magnetic resonance spectroscopy of patients with mesial temporal sclerosis.

OBJECTIVE: We evaluated extratemporal metabolic changes with phosphorus magnetic resonance spectroscopy (31P-MRS) in patients with unilateral mesial temporal sclerosis (MTS). METHOD: 31P-MRS of 33 patients with unilateral MTS was compared with 31 controls. The voxels were selected in the anterior, posterior insula-basal ganglia (AIBG, PIBG) and frontal lobes (FL). Relative values of phosphodiesters- PDE, phosphomonoesters-PME, inorganic phosphate - Pi, phosphocreatine- PCr, total adenosine triphosphate [ATPt = γ- + a- + b-ATP] and the ratios PCr/ATPt, PCr/γ-ATP, PCr/Pi and PME/PDE were obtained. RESULTS: We found energetic abnormalities in the MTS patients compared to the controls with Pi reduction bilaterally in the AIBG and ipsilaterally in the PIBG and the contralateral FL; there was also decreased PCr/γ-ATP in the ipsilateral AIBG and PIBG. Increased ATPT in the contralateral AIBG and increased γ-ATP in the ipsilateral PIBG were detected. CONCLUSION: Widespread energy dysfunction was detected in patients with unilateral MTS.

Extratemporal abnormalities in phosphorus magnetic resonance spectroscopy of patients with mesial temporal sclerosis / Anormalidades extratemporais na espectroscopia de fósforo por ressonância magnética em pacientes com esclerose mesial temporal

ABSTRACT Objective We evaluated extratemporal metabolic changes with phosphorus magnetic resonance spectroscopy (31P-MRS) in patients with unilateral mesial temporal sclerosis (MTS). Method 31P-MRS of 33 patients with unilateral MTS was compared with 31 controls. The voxels were selected in the anterior, posterior insula-basal ganglia (AIBG, PIBG) and frontal lobes (FL). Relative values of phosphodiesters- PDE, phosphomonoesters-PME, inorganic phosphate - Pi, phosphocreatine- PCr, total adenosine triphosphate [ATPt = γ- + a- + b-ATP] and the ratios PCr/ATPt, PCr/γ-ATP, PCr/Pi and PME/PDE were obtained. Results We found energetic abnormalities in the MTS patients compared to the controls with Pi reduction bilaterally in the AIBG and ipsilaterally in the PIBG and the contralateral FL; there was also decreased PCr/γ-ATP in the ipsilateral AIBG and PIBG. Increased ATPT in the contralateral AIBG and increased γ-ATP in the ipsilateral PIBG were detected. Conclusion Widespread energy dysfunction was detected in patients with unilateral MTS.

RESUMO Objetivo Nós avaliamos as alterações metabóblicas através da espectroscopia de fósforo por ressonância magnética (31P-MRS) em pacientes com esclerose mesial temporal (EMT) unilateral. Método 31P-MRS de 33 pacientes com EMT unilateral foram comparadas aos de 31 controles. Foram selecionados os voxels nas regiões insulonuclear anterior e posterior (RINA e RINP) e frontal (RF). Os valores relativos de fosfodiésteres – PDE, fosfomonoésteres- PME, fosfato inorgânico- Pi, fosfocreatina –PCr, adenosina trifosfato total [ATPt = γ- + a- + b-ATP] e as razões PCr/ATPt, PCr/γ-ATP, PCr/Pi e PME/PDE foram obtidas. Resultados Nós encontramos anormalidades em pacientes com EMT em comparação aos controles. Redução de Pi nas RINA bilateralmente, RINP ipsilateral e RF contralateral, redução de PCr/γ-ATP nas RINA e RINP ipsilaterais foram detectadas. Aumentos de ATPT na RINA contralateral e aumento de γ-ATP na RINP ipsilateral também foram encontradas. Conclusão Disfunção energética difusa foi encontrada em pacientes com EMT unilateral.

Avaliação por imagem por tensor de difusão do corpo caloso em pacientes com epilepsia mesial temporal e esclerose hipocampal / Diffusion tensor imaging of the CC of patients with mesial temporal epilepsy and hippocampal sclerosis

Introdução Epilepsia do lobo temporal mesial (ELTM) por esclerose hipocampal (EH) é a forma de epilepsia focal mais comum na idade adulta e a causa mais frequente de refratariedade ao tratamento clínico. Apesar de se tratar de uma patologia da substância cinzenta, alguns estudos, por meio da imagem por tensor de difusão (diffusion tensor imaging-DTI), têm demonstrado alteração da substância branca temporal e extratemporal nestes pacientes. O corpo caloso (CC) é a maior comissura cerebral conectando áreas corticais homólogas de ambos os hemisférios cerebrais e tem sido implicado na propagação da atividade epiléptica. O objetivo principal do presente estudo foi avaliar possíveis alterações no CC de pacientes com ELTM-EH pela técnica de DTI e verificar se essas dependem da lateralidade da EH e da concordância entre os exames de ressonância magnética (RM) e os exames de vídeo-eletroencefalograma (EEG). Como objetivo secundário, também avaliou-se se estas alterações se correlacionavam com alguma variável clínica ou com as medidas volumétricas do CC. MÉTODOS: 42 pacientes com ELTM-EH (idades: 20-54 anos) e 30 voluntários saudáveis como grupo controle (idades: 18-53 anos) realizaram exame de RM de crânio, sendo obtidas sequências de DTI com 32 direções de gradiente e imagens volumétricas ponderadas em T1. Os pacientes foram também divididos em subgrupos: EH à direita e EH à esquerda, e em pacientes concordantes e discordantes. Os valores de anisotropia fracionada (AF), difusividade média (DM), difusividade axial (DA), difusividade radial (DR) e os dados volumétricos foram extraídos a partir de cinco segmentos obtidos automaticamente na secção sagital do CC. Foram realizadas comparações dos parâmetros de DTI no CC entre os grupos de pacientes e controles, e entre os subgrupos de pacientes. Foram investigadas correlações entre os parâmetros do tensor de difusão e as variáveis clínicas. As alterações volumétricas no CC dos pacientes com ELTM-EH bem como a correlação...

Introduction: Mesial temporal lobe epilepsy (MTLE) with hippocampal sclerosis (HS) is the most common form of focal epilepsy in adults and it is frequently associated with refractoriness to medical treatment. Although epilepsy is considered a grey-matter disease, abnormalities in the temporal and extra-temporal white matter have been identified in these patients with diffusion tensor imaging (DTI). The corpus callosum (CC) is the major white matter tract connecting both cerebral hemispheres and has been implicated as an important route of spread of epileptic activity. The first goal of this study was to detect DTI abnormalities in specific areas of the CC in patients with MTLE-HS and to verify if these abnormalities depend on the laterality of the HS and on the concordance between the magnetic resonance imaging (MRI) and video-electroencephalogram (EEG). As a second goal we assessed if DTI results were correlated with any clinical variable or volumetric changes of the CC. METHODS: 42 patients (age: 20-54 years) and 30 healthy controls (age:18-53 years) were submitted to brain MRI. DTI sequences with 32 gradient encoding directions and volumetric T1-weighted images were obtained. Additionally, we grouped the patients in left sided and right sided HS and in concordant and discordant HS. Mean values of fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD) and volumetric results were extracted from five segments at the midsagittal section of the CC obtained through automatic segmentation. Comparisons of DTI parameters of the CC were performed between patients and controls and between subgroups of patients. Correlations between DTI parameters and clinical findings were calculated. We also evaluated volume abnormalities of the CC in MTLE-HS patients and the correlations between these abnormalities and DTI changes. We considered a value of p <0.05 statistically significant. RESULTS: Our study showed that, when HS patients...

Corpus callosum microstructural changes correlate with cognitive dysfunction in early stages of relapsing-remitting multiple sclerosis: axial and radial diffusivities approach.

The corpus callosum is the largest fiber bundle in the central nervous system and it takes part in several cognitive pathways. It can be affected by multiple sclerosis (MS) early in the disease. DTI is capable of infering the microstructural organization of the white matter. The vectorial analysis of the DTI offers the more specific indices of axial diffusivity (AD) and radial diffusivity (RD), which have shown to be useful to discriminate myelin damage from axon loss, respectively. This study presents DTI results (mean diffusivity (MD), fractional anisotropy (FA), RD, and AD) of 23 relapsing-remitting MS patients and its correlation with cognitive performance. There were 47.8% of cognitive impaired patients (MS CI). We found signs of demyelination, reflected by increased RD, and incipient axon loss, reflected by AD increase, which was slightly higher in the MS CI. The cognitive changes correlated with the DTI parameters, suggesting that loss of complexity in CC connections can impair neural conduction. Thus, cognitive impairment can be related to callosal disconnection, and DTI can be a promising tool to evaluate those changes.