| Objective To study cerebral microstructure changes in patients with idiopathic epilepsy by diffusion tensor magnetic resonance imaging technique, and analyze correlation between abnormal brain region and clinical variable, and explore its value for pathophysiology study of idiopathic epilepsy, and provide a theoretical basis for diagnosis and treatment of epilepsy.Methods Thirty patients were selected, and twenty-one health volunteers as control group. This study belongs to cross-sectional study, case-control study. Patient group come from Affiliated Hospital of Zunyi Medical College. The patients were diagnosed by experienced doctor of Neurology and pediatrics, according to the diagnostic criteria of the International League Against Epilepsy and other related auxiliary examination. Nine patients were excluded because of the intracranial organic disease found by conventional MRI or the head movement more than 1mm. So,21 cases were analyzed finally. All the patients and volunteers were right-handed. MRI scan was performed using a 3.0 T MR imaging system (Simens 3.0T trio), DTI was performed using the diffusion gradient directions with 20 single-shot echo planar imaging (EPI) sequence covering the whole brain. DTI data was calculated using DTI-studio (http://cmrm.med.jhmi.edu/) for each subjects, including apparent diffusion coefficient (average diffusion coefficient ADC) maps, fractional anisotropy (fractional anisotropy FA) maps and images b value of zero (B0 map). Two kind analystic methods were performed. First, regions of interest (ROI)analysis, The defiend ROIs were manually outlined with syngo MR B15 (Simens company) post processing software, including the hippocampus, amygdale, thalamus and corpus callosum, and extracted the value of FA and ADC values. The ROI varied with the shape and size of the region shape and size to minimize the volume effect on the measurement. Statistical analysis were performed by independent samples T test. The differences of p<0.05 would be considered as statistical significance. Second, voxel-based analysis (VBA).DTI data processing and analysis were performed with voxel-wise analysis approaches as implemented in statistical paremetric mapping software (http://www.fil.ion. ucl.ac.uk/spm/software/SPM2), including coregister, normalization and smoothing. Statistical analysis were made using two sample-test.Results Age, sex and handedness between epilepsy group and control group were no statistically different. Comparing with control group, ROI analysis found FA values reduction in the head right hippocampus, the amygdale and the left hippocampus (p<0.05) in patients with epilepsy. VBA analysis showed FA values reduction in the right temporal lobe, right insula, right anterior cingulate and right cerebellar dentate nuclei (p<0.05) compared with normal control group; ADC values increased in right forelimb of the internal capsule and the external capsule (p<0.05). Pearson correlation analysis showed that ADC values was correlated with illness duration in right head of hippocampus and amygdala by ROI analysis and in right temporal lobe, frontal lobe, occipital lobe and right forelimb of the internal capsule (p<0.05) by VBA analysis.Conclusions DTI examination could detect subtle neuropathology changes in patients with idiopathic epilepsy. Moreover, ADC values abnormal in some brain areas was correlated with illness duration in patients with idiopathic epilepsy, provided a theoretical basis for pathophysiology study, diagnosis and treatment of epilepsy. |
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