Investigating the potential of tensor-valued diffusion encoding to detect and characterise Focal Cortical Dysplasia in paediatric epilepsy

Motivation: Radiological assessment of focal cortical dysplasia (FCD), the most common form of drug-resistant paediatric epilepsy, remains challenging on conventional MRI. Goal(s): Our goal was to test whether tensor-valued diffusion encoding, which provides metrics related to size variance and microscopic anisotropy, can be used to detect and characterise FCD. Approach: Paediatric patients were scanned with a prototype tensor-valued diffusion encoding sequence and parameter estimates were visually and statistically compared. Results: While the diffusion maps provide no strong contrast compared to structural images, our statistical results reflect FCD microstructural heterogeneity when comparing FCD and homotopic grey matter regions. Impact: Comparison of tensor-valued diffusion encoding parameters reflects FCD heterogeneity, potentially relating to lesion subtype. Despite weak contrast for FCD detection at present, this method could aid in vivo FCD characterisation in radiological assessment workflow prior to surgery.