Reduction of gray and white matters in patients with temporal lobe epilepsy and its correlation with disease duration

Abstract

To measure the volumetric changes of gray and white matters in patients with temporal lobe epilepsy(TLE)using voxel-based morphometric study(VBM)and correlate the changes with clinical parameters. A total of 71 TLE patients were enrolled in the study,and 22 healthy subjects served as normal controls. Routine brain MRI and 3D fast spoiled gradient echo(FSPGR)T1-weighted images of all the subjects were acquired. The 3D structural images were co-registered,segmented and smoothed,and then the images were analyzed using the optimized VBM with preprocessed using Diffeomorphic Anatomical Registration using Exponentiated Lie algebra(DARTEL)algorithm. The global and local gray matter and white matter volume of each subject were calculated and compared between the TLE patients and normal controls. The potential correlations between the changes of the global and local gray and white matters in the TLE patients and the clinical parameters including the age at onset and the duration of epilepsy were explored. Compared to the normal controls,the TLE patients had diffuse volumetric reduction of gray and white matters in cerebrum both ipsilateral and contralateral to the seizure focus(P<0.05). Local gray matter reduction was found extensively in bilateral cerebral lobes,especially in the temporal and frontal lobes. Local white matter reduction was found in bilateral temporal,parietal and frontal lobes,in addition to the cingulate gyrus. The global gray matter volume(Global GMV)and the global white matter volume(Global WMV)were negatively correlated to the duration of epilepsy with the most significant change occurring in the first year of epilepsy. Global WMV dropped more quickly than Global GMV during the prolonged disease course. TLE patients have diffuse gray matter and white matter reduction,particularly in the early stage of epilepsy. The reduction of the white matter is more obvious than the gray matter.