2.3. Neuroimaging

All patients had their presurgical MRI at 1.5 or 3 Tesla performed between 2015 and 2018. Brain MRI studies consisted of the following sequences: sagittal T1‐weighted image, axial and coronal T2‐weighted images, axial and coronal fluid‐attenuated inversion recovery (FLAIR) images, axial gradient echo (GRE) T2*‐susceptible image or susceptibility‐weighted image (SWI), coronal inversion recovery (IR) image, and axial 3‐dimensional (3D) T1‐weighted fast spoiled gradient echo (FSPGR) with brain volume (BRAVO) image. Additional sequences for some cases may have included axial diffusion‐weighted image (DWI), axial apparent‐diffusion coefficient (ADC) image, axial IR image, and coronal and sagittal 3D T1‐weighted FSPGR with BRAVO images. Contrast medium was administered in 3 cases (no. 1, 8, and 11) during presurgical MRI study.

In our study, presurgical MRIs were rated based on documented radiological reports by neuroradiologists for the presence or absence of lesional brain abnormalities and whether the epileptogenic lesion is frontal or extra‐frontal, that is, extending beyond the frontal lobe.