MRI and 1H-MRS detects volumetric and metabolic abnormalities of hippocampal sclerosis in temporal lobe epilepsy

ObjectiveTo further investigate the ability of MRI and 1H-MRS techniques for presurgical evaluation of hippocampal sclerosis.MethodsMRI and 1H-MRS were performed on 30 healthy subjects to determine the confidence levels. Eight patients who were pathologically confirmed hippocampal sclerosis were then studied using the same protocols. The difference of hippocampal formation (DHF) was used to determine atrophy of hippocampus. Areas under the peak of N-acetylaspartate(NAA), Creatine(Cr) and Choline (Cho) were measured, and the ratios of NAA/Cr, Cho/Cr, and NAA/Cr+Cho were calculated. NAA/Cr+Cho value was applied to localize the seizure focus.ResultsTwo patients showed hippocampal atrophy according to DHF value. NAA/Cr ratio decreased significantly in ipsilateral hippocampus compared to that in contralateral hippocampus and control subjects(P < 0.01). Cho/Cr value increased in both ipsi- and contralateral hippocampus in comparison with that in control subjects(P < 0.01). NAA/Cr+Cho ratio, however, significantly reduced in both ipsi-and contralateral hippocampus(P < 0.01) with lowest NAA/Cr+Cho ratio in seizure foci. Six patients could be lateralized by reduced and/or asymmetric NAA/Cr+Cho value.Conclusion1H-MRS should be a promising diagnostic tool to detect neuron abnormality. 1H-MRS and MRI complement each other in presurgical lateralization of epileptogenic lesion in epilepsy patients.