Microstructural characterisation of focal cortical dysplasia in paediatric epilepsy patients using clinical MRI

Motivation: Brain surgery is the most effective treatment for drug-resistant epilepsy, as children with ongoing seizures often have poor outcomes. New non-invasive imaging methods are needed to enhance the detection of subtle lesions thought to occur in 33% of these children. Goal(s): We implemented a clinically feasible diffusion MRI protocol to characterise cortical microstructure in children with drug-resistant epilepsy. Approach: We applied biophysical modelling and compared the microstructure of dysplastic cortex with normal appearing cortex. Results: Our observations of higher apparent soma radius in areas of dysplastic cortex was consistent with the expected pathology of enlarged dysmorphic neurons in type-II focal cortical dysplasia (FCD). Impact: Our findings highlight the utility of a new imaging marker, the apparent soma radius, in characterising FCD. By combining this measure into clinical work-ups we can increase confidence in radiological diagnoses of subtle FCDs and in turn assess surgical candidacy.