Analysis of cortical dysplasias using b-tensor encoding diffusion MRI in an animal model

COEX 

Focal cortical dysplasias (FCD) are cortical malformations that represent a major cause of drug-resistant focal epilepsy (Blümcke, 2011). Magnetic resonance images (MRI) are the main tool for their diagnosis and subsequent surgical intervention. However, despite clear histopathological changes, many FCDs lack macro-anatomical abnormalities, often going undetected (Guerrini & Barba, 2021). It is necessary to find better methods for their detection.
Diffusion weighted MRI (dMRI) is ideally suited to probe the architecture of tissue. However, in complex structures such as the cortex, conventional dMRI methods (e.g. DTI) are insufficient (Benjamini, 2021). Novel dMRI methods have been used to reflect regional and layer-level abnormalities in the cerebral cortex of rodents (Villaseñor et al., 2023) and humans (Lampinen 2020, Lorio 2020).
The b-tensor encoding method provides additional information contained in the dMRI signal and yields parameters more specific to the microstructure of tissue. Q-space trajectory imaging (QTI), an analysis technique for b-tensor encoding images, is used to derive micro fractional anisotropy (µFA) and orientation coherence (Cc), information that is not available with standard dMRI (Westin, 2016).
We show the ability of b-tensor dMRI to evaluate the characteristics of the microarchitecture of the cerebral cortex in a rodent model of cortical dysplasia, aiming to improve the detection of FCDs in clinical populations.