Epilepsy cases: fMRI and MR tractography as qualitative and quantitative tools for proper localization and pre-operative planning

Functional MRI is a relatively new noninvasive brain imaging technique that has been used for neuroscience research applications since the early 1990s. This technique relies on the blood oxygenation level dependent [BOLD] effect. Diffusion tensor magnetic resonance imaging [DTI] is a noninvasive technique that can be used to assess the integrity of cerebral tissue. We evaluated 16 patients with unilateral MTLE. We did MRI for language and memory areas for localization and lateralization of the dominating cortical areas concerned with language and memory. Diffusion-weighted images along twelve different directions with a b value of 1000 s/mm2. A 1.5-T scanner was used to acquire those examinations. For DTI we compared the mean diffusivity [MD] and fractional anisotropy [FA] from symmetrical voxels by sampling the basal ganglia, thalamus, hippocampus and parahippocampus regions bilaterally. We compared measurements with the EEG, high-resolution MR imaging, as well as clinical data. For MR tractography, various tracts were traced including the Meyer's loop. Among the study group only 5 patients with partial epilepsy out of 16 are promising candidates for surgery representing only 31.25% among the study population 68.75% of our study population were excluded according to our quantitative and qualitative tools. Combined fMRI with MR tractography are valuable qualitative and quantitative tools for proper localization and lateralization of the eloquent areas including memory, language areas and Meyer's loop in the selection of promising epilepsy surgery candidates and for pre-operative planning