Abstracts

Rationale: To correlate the clinical variables with the degrees of change in subcortical nuclei of patients with focal neocortical epilepsy and without MRI abnormality. Methods: We analyzed the diffusion and morphometric parameters of MRI data collected from 24 patients with chronic neocortical seizures and 29 neurologically normal controls. FMRIB's Integrated Registration and Segmentation Tool (FIRST) was used to segment hippocampus, striatum (caudate nucleus and putamen), globus pallidus, nucleus accumbens, thalamus, and amygdala from individual three-dimensional spoiled gradient (3D-SPGR) MRI and diffusion tensor MRI. The volumes, values of apparent diffusion coefficient (ADC) and fractional anisotropy (FA) of the interested regions were correlated with age of seizure onset and disease duration. Group differences of the subcortical structures were evaluated by vertex-wise shape analysis. Results: Significant atrophy of bilateral thalami and putamens, left caudate and amygdala; and significantly decreased FA value in bilateral accumbens and increased ADC value in left thalamus, right pallidum, and right hippocampus were observed. The normalized volume of right accubens correlated with age of seizure onset. The normalized volume of left thalamus, the ADC of left putamen, the FA values of left putamen and bilateral hippocampi correlated with disease duration. Conclusions: There was widespread subcortical gray matter abnormality in patients with nonlesional localization-related epilepsy, which was correlated with age of seizure onset and disease duration. The destruction in subcortical structures may reflect pre-existing brain abnormality and progressive brain degeneration in patients with chronic and severe epilepsies.