Mirrored structural symmetry index (VMSSI): a novel approach for diagnosing MR-negative focal cortical dysplasia using structural MRI

BackgroundFocal cortical dysplasia (FCD) is a common cause of drug-resistant epilepsy, yet its diagnosis remains challenging, particularly for magnetic resonance imaging (MRI)-negative FCD. In this study, we propose a novel metric, the Voxel-Mirrored Structural Symmetry Index (VMSSI), to quantify hemispheric structural symmetry using T1-weighted MRI.MethodsA total of 104 patients with suspected FCD and 104 age and sex matched healthy controls from two centers were enrolled, and their brain image