Brno Epilepsy Centre, Department of Neurology, St. Anne’s University Hospital, Brno, MR Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Prague, Department of Nuclear Magnetic Resonance, Institute of Scientific Instruments, Academy of Sciences, Brno, Department of Neuroimaging, St. Anne’s University Hospital, Brno, Czech Republic
Purpose: to investigate potential neuronal dysfunction within the thalamus in patients suffering from mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE/HS). Methods: we examined twenty epileptic patients suffering from mesial temporal lobe epilepsy with hippocampal sclerosis (17 females, 3 males) and twenty sex- and age-matched healthy controls. H MR spectroscopic imaging (SI) was performed over the right and left thalamus in all patients and controls. In addition both hippocampi were investigated by the H MR spectroscopic single voxel (SV) technique in both groups. Results: statistical analysis of compared data in both groups demonstrated that the total thalamic NAA level was significantly decreased in patients with MTLE/HS as compared to healthy controls. Detailed analysis revealed a statistically significant reduction of NAA, NAA/Cr and NAA/(Cr+Cho) ratios in the thalamus ipsilateral to hippocampus affected with hippocampal sclerosis in patients compared to controls, while no significant changes were observed in the thalamus contralateral to sclerotic hippocampus. A comparison of values in ipsilateral and contralateral thalami in patients showed statistically significant difference with lower values of NAA and both ratios in the ipsilateral thalamus. Previously reported reduced hippocampal concentration of NAA, NAA/Cr and NAA/(Cr+Cho) ratios on the side of hippocampal sclerosis compared with contralateral hippocampus in patients and both hippocampi in controls was confirmed. Conclusions: the present MRS data clearly indicate neuronal dysfunction within the thalamus ipsilateral to the sclerotic hippocampus of patients with mesial temporal lobe epilepsy. In agreement with other recent functional and structural neuroimagings our results confirm the role of the ipsilateral thalamus in the medial temporal/limbic epileptic network.