Diagnosis and localization of imaging negative frontal focal cortical dysplasias by video electroencephalogram and diffusion tensor imaging

Abstract

Objective To investigate the methods of diagnosis and localization for imaging negative frontal focal cortical dysplasia (FCD),and provide the basis fo operation treatment.Methods Twenty-eighty patients with imaging negative frontal FCD,admitted to our hospital from March 2008 to June 2010 and proved by pathological diagnosis,were chosen in our study; retrospective analysis on their clinical data,video electroencephalogram (VEEG) and diffusion tensor imaging (DTI) data was performed.Results The spike wave of paroxysmin and discharge at interictal phase was noted in 21 patients,including 16 with frontal advantage and multiple lesions.The apparent diffusion coefficient in the regions of interest was significantly increased,while the fractional anisotropy value was significantly decreased as compared with the contralateral ones (P＜0.05).Pathological reports showed 6 FCD type ⅠA,9 type ⅠB,8 type ⅠC and 5 FCD type ⅡA in all 28 patients treated by operation.All patients were followed up for 12 to 26 months,with an average of 17.3 months.Engel' s I grade A was noted in 7,grade B in 10,grade Ⅱ in 8,and grade Ⅲ in 3.Conclusion Combined application of VEEG and DTI can accurately diagnose and locate the negative imaging frontal FCD,guide the precise excision of epileptogenic focus and improve the control rate of frontal lobe epilepsy. Key words: Video electroencephalogram; Diffusion tensor imaging; Focal cortical dysplasia