Figure 4. Example of Focal Cortical Dysplasia at 7T.

Axial 3T T₁-weighted MPRAGE (A), axial 7T T₁-weighted MP2RAGE (B), and zoomed in axial 7T T₂*-weighted GRE (C) images of a patient for whom visual review of 7T MRI yielded previously unappreciated subtle findings. The red crosshairs/arrows pinpoint the location of an area of focal cortical dysplasia (FCD), which was detected by visual analysis of 7T images. The vascular changes associated with the FCD can be well appreciated on the T₂*-weighted GRE images in panel C (arrows). Detection of this subtle lesion guided subsequent placement of intracranial-EEG (icEEG) with subdural grids and depth electrodes. The icEEG implantation was devised to confirm the epileptogenicity of the subtle lesion and map out the lesion extent and its proximity to eloquent cortex with language function. The subtle lesion location was concordant with ictal onset on the icEEG as shown in the 3D reconstruction of electrode location and 7T MRI, with a 2D axial cut-plane (D). In panel D, green spheres indicate all implanted electrodes and red spheres indicate ictal onset.