QUANTITATIVE MRI IN PATIENTS WITH IDIOPATHIC GENERALIZED EPILEPSY - EVIDENCE OF WIDESPREAD CEREBRAL STRUCTURAL-CHANGES

In patients with idiopathic generalized epilepsy (IGE), visual inspect ion of routine MRT. is normal, However, pathological studies have show n microdysgenesis in grey and white matter in a large percentage of au topsies from cases of IGE, Recently, widespread structural changes not evident on visual inspection of high resolution MRT have been shown u sing quantitative MRI in patients with apparently focal cerebral dysge nesis. We sought to determine whether similar quantitative changes mig ht be present in patients with IGE, reflecting possible underlying str uctural abnormalities. Twenty patients with juvenile myoclonic epileps y, 10 patients each with childhood absence epilepsy and juvenile absen ce epilepsy, five patients with tonic-clonic seizures on awakening and 30 control subjects had T-1-weighted volume acquisition MRI scans on a 1.5T GE scanner. The cerebral hemispheres were segmented semi-automa tically, allowing the comparison of normalized cortical and subcortica l matter volumes between groups, and investigation of the regional dis tribution of cortical and subcortical matter in individual subjects. P atients with IGE had significantly larger cortical grey matter volumes than control subjects. Significant abnormalities of the regional dist ribution of cerebral grey and subcortical matter were found in eight o ut of 20 patients with juvenile myoclonic epilepsy, one out of 10 pati ents with childhood absence epilepsy, four out of 10 patients with juv enile absence epilepsy and two out of five patients with tonic-clonic seizures on awakening, but in none of the 30 control subjects. Using M RI-segmentation, we identified widespread cerebral structural changes in patients with various IGE syndromes. Quantitative MRI supports the existence of structural abnormalities in patients with IGE.