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Background and Purpose:Idiopathic generalized epilepsy(IGE),characterized by the widespread generalized spike-and-waves or polyspike–waves and undetectable focal anatomical brain abnormalities,and encompasses a group of epileptic disorders.1 Although there is increasing evidence suggesting that there may be subtle abnormalities in IGE patients using modern neuroimaging techniques,most of these previous studies focused on the brain grey matter,2 leaving the underlying white matter abnormalities in IGE largely unknown.Methods:Diffusion tensor imaging(DTI)is a magnetic resonance imaging(MRI)technique that can characterize white matter(WM)architecture and microstructure.3DTI scans were performed on20 patients with GTCS patients and 20 well-matched healthy subjects.Tract-based spatialstatistics(TBSS)approach was employed to analyze the scans.Fractional anisotropy(FA)was calculated and group differences were analyzed using tract-based spatial statistics(TBSS).Additionally,correlations were performed between fractional anisotropy(FA)and duration of disease.Results:Voxel-wise statistics revealed five brain WM tracts with lower fractional anisotropy(FA)in patients compared to healthy subjects in the genu and body of corpus callosum,the bilateral anterior corona radiata and the right posterior corona radiata.Moreover,negative correlations were found in all those significantly reduced regions.Discussion: The primary finding in this study is that the GTCS group exhibitedsignificant lower FA values in the projection fibers(anterior and posteriorcorona radiata)and the genu and body of corpus callosum(CC).The current findings firstprovide information of altered WM integrity in the most common subtype of IGE patients.The CC is a critical pathway in the inter-hemispheric connectivity and participates in the organization of complex tasks that involve major cortical areas.4 The genu contains fibers projecting to or from the prefrontal region.3,5 The body contains fibers related to premotor,supplementary motor and primary motor cortical areas.3,4 The CC may also be involved in pathophysiology,such as in seizure propagation which is supported by the observation that corpus colostomy can be an effective treatment for some patients with medically intractable epilepsy.6Decreased FA values in CC might result in abnormalities of the integration of high levelcognitive,linguistic and perceptual processing.7 Using TBSSapproach,Kieseppa et al.8found suggestive decreased FA inthe posterior body of CC.Consistent with previousstudies,the current study indicates that the lower FA in the genuof the CC might contribute to the functional alterationsin the inter-hemispheric system of emotional regulation inepilepsy.The corona radiata is related to the cortico-spinal tract,the cortico-pontinetract,and the cortico-bulbar tract.8,9Altered WM integrity of the corona radiata gives rise to a set of motor signs and symptoms.10Our results stronglysuggest the involvement of the bilateral anterior corona radiatain the pathogenesis of patients withGTCS.Although this finding could be confounded by the small sample size,it is also possible that the alterations of FA in theseregions may be a trait marker for epileptic patients regardless of the severity of symptoms and other related factors.