Evaluation of White Matter abnormalities in patients with Focal Cortical Dysplasia using qualitative analysis of fractional anisotropy maps.

PRINCICH J.P; KAUFFMAN M; SEIFER,G; BLENKMANN, A; CONSALVO D; KOCHEN S

Roma

Congreso; 29th International Epilepsy Congress; 2011

 Introduction: Drug resistant epilepsy is associated frequently with malformations of cortical development (MCD); focal cortical dysplasia (FCD) is the most frequent type of MCD. The surgical failure and electroclinical heterogeneity in these patients may be due to the presence of more extensive, non-MRI visible epileptogenic FCD or microstructural disorganization. Reduced Fractional Anisotropy (FA) has been reported in the subcortical white matter underlying FCD patients with anomalies extending beyond the structural abnormalities seen with conventional MRI. Methods:  We scanned 21 healthy subjects and 22 patients with drug resistant epilepsy and FCD using DTI. A qualitative analysis was systematically performed, by two independent examiners blinded to clinical and structural MRI findings. The asymmetries between hemisphere and regions were defined when both examiners agreed or when there was discrepancy by consensus. Afterwards these areas of asymmetries were superimposed on the structural MRI to evaluate a relationship between the FCD lesion and the asymmetry determined on the FA maps for each individual patient.  Results:  Eleven patients (50%) presented asymmetries in the FA maps, in ten of these patients the areas of decreased FA were around and exceeding the FCD limits detected on T1/Flair images.  Three patients of this group had also widespread areas of increased or decreased FA which extended beyond the area of FCD.  Conclusion:  The asymmetries described were detected during visual analysis of FA maps, and we believe that this could be a sensitive tool to evaluate patients with FCD that are known to present electroclinical heterogeneity.