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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.

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Temporal lobe epilepsy (TLE) is the most common form of epilepsy in adult patients and the mesial temporal sclerosis (MTS) is the most frequent entity associated with medically refractory TLE. MTS is characterized by selective neuronal loss in CA1, CA3 and the dentate gyrus of the hippocampus. MTS may also involve the amygdala, parahippocampal gyrus, and entorhinal cortex. More widespread temporal lobe involvement may also occur 5 and single-photon emission computed tomography (SPECT) 6 studies in which extensive temporal and extratemporal structural and metabolic involvement in epilepsy has been associated with MTS. AbstrActObjective: We evaluated extratemporal metabolic changes with phosphorus magnetic resonance spectroscopy ( 31 P-MRS) in patients with unilateral mesial temporal sclerosis (MTS). Method: 31 P-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 [ATP t = g-+ a-+ b-ATP] and the ratios PCr/ATP t, PCr/g-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/g-ATP in the ipsilateral AIBG and PIBG. Increased ATP T in the contralateral AIBG and increased g-ATP in the ipsilateral PIBG were detected. Conclusion: Widespread energy dysfunction was detected in patients with unilateral MTS.Keywords: phosphorus spectroscopy, magnetic resonance imaging, neurometabolism, mesial temporal sclerosis, epilepsy. rEsumo Objetivo: Nós avaliamos as alterações metabóblicas através da espectroscopia de fósforo por ressonância magnética ( 31 P-MRS) em pacientes com esclerose mesial temporal (EMT) unilateral. Método: 31 P-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 [ATP t = g-+ a-+ b-ATP] e as razões PCr/ATP t, PCr/g-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/g-ATP nas RINA e RINP ipsilaterais foram detectadas. Aumentos de ATP T na RINA contralateral e aumento de g-ATP na RINP ipsilateral também foram encontradas. Conclusão: Disfunção energética difusa foi encontrada em pacientes com EMT unilateral.Palavras-chave: espectroscopia de fósforo, ressonância magnética, neurometabolismo, esclerose mesial temporal, epilepsia.