A High-resolution Magnetic Resonance Study On The Brain Structure Characteristics Of Patients With First-episode Idiopathic Generalized Epilepsy

Part One:Cortical morphologic changes in recent-onset,drug-na?ve idiopathic generalized epilepsyObjective: So far,only a few studies of structural MRI of recent-onset drug-na?ve idiopathic generalized epilepsy(IGE)investigated subtle brain morphology abnormalities,mainly reported brain volume changes.In the present study,we aimed to investigate both cortical thickness,volume and surface area differences using Freesufer in a cohort of recent-onset,drug-na?ve IGE.Further,we need to analyze wether the cortical morphology abnormality is correlated with their clinical characteristics(including onset age,duration of epilepsy and mini-mental state examination(MMSE)).Methods: Forty-five first-episode,drug-na?ve patients diagnosed of IGE within the past 6 months(age range: 5-18 years,males:females = 26:19)were recruited,and 32 age,sex,handedness and education degree matched healthy controls(age range: 5-18 years,males: females = 21:11)were collected.All patients and control subjects underwent magnetic resonance imaging in a 3.0 T MR scanner system(Intera Achieva;Philips Medical Systems,Amsterdam,the Netherlands).An 16-channel phased-array head and neck coil were used to improve the signal noise ratio(SNR).Both groups were underwent conventional head MRI(T1WI、T2WI、T2-FLAIR)、DWI、high-resolution 3-dimensional T1-weighted(3D-T1WI)sequence scan.All 3D-T1 WI images were obtained with a spoiled gradient recalled(SPGR)sequence.The FreeSurfer software was used to calculate the difference of brain cortical thickness,surface area and volume between the two groups.The differences of cortical morphology between patients and controls were compared based on general linear model,and a Monte Carlo correction was used for multiple comparison correction(P<0.05).The regions that showed group differences after multiple comparison correction were extracted in common space for each individual,and the mean morphometric parameters in each region of patient group were correlated with their clinical characteristics(including onset age,duration of epilepsy and MMSE).Results: Compared with healthy controls,IGE patients showed decreased cortical thickness in left rostral middle frontal gyrus,decreased volume in right cuneus,left superior frontal gyrus which extend to precentral gyrus,and decreased surface area in right cuneus and right inferior parietal gyrus(P<0.05,after multiple comparison correction).None of these regions showed significant relationship with clinical measurements in patient group.Conclusions: In the present study,Our findings suggest that there are brain morphology changes in the early course of the disease,which provides neuroimaging evidence for the study of the pathogenesis of IGE.Part Two: Differences in brain structure between refractory and nonrefractory patients with idiopathic generalized epilepsyObjective: To explore the pathophysiological mechanism of refractory IGE by comparing the brain gray matter volume(GMV)and white matter(WM)difference in patients with refractory and non-refractory IGE.Methods: Seventy-five first-episode,drug-naive patients diagnosed of IGE within the past 6 months were recruited.All patients underwent magnetic resonance imaging in a 3.0 T MR scanner system(Intera Achieva;Philips Medical Systems,Amsterdam,the Netherlands).An 16-channel phased-array head and neck coil were used to improve the signal noise ratio(SNR).All patients underwent conventional head MRI(T1WI、T2WI、T2-FLAIR)、DWI、3D-T1WI、DTI sequence scan.All 3D-T1 WI images were obtained with a SPGR sequence.All patients taking anti-epilepsy drugs were followed up for at least 2 years.Finally,45 patients with regular anti-epileptic therapy under the guidance of the doctor were selected,including eight refractory and thirty-seven non-refractory patients.Two-sample t-test were used to compare the difference of GMV and WM between the two groups.Results: Compared with non-refractory group,refractory group showed decreased GMV in left superior temporal gyrus and right inferior frontal gyrus,increased GMV in bilateral posterior cerebellar lobe;refractory IGE patients showed decreased FA in right WM of postcentral gyrus,right WM of temporal lobe as well as increased MD in left precuneus and right WM of inferior parietal lobule.Conclusions: Refractory and non-refractory IGE patients group have subtle brain structural abnormalities,suggesting that IGE develops into refractory epilepsy may be associated with these brain structural abnormalities.