Interictal diffusion MRI in partial epilepsies explored with intracerebral electrodes

Area of Science:

• Neuroimaging
• Epilepsy Research
• Medical Diagnostics

Background:

• Refractory partial seizures often necessitate epilepsy surgery.
• Precise localization of the epileptogenic zone (EZ) is crucial but typically requires invasive methods.
• Exploring non-invasive imaging techniques like Diffusion Tensor Imaging (DTI) is vital for improving surgical planning.

Purpose of the Study:

• To evaluate DTI as a non-invasive tool for locating the EZ in epilepsy patients.
• To assess DTI's utility in guiding the placement of electrodes for stereo-electroencephalography (SEEG).
• To compare DTI findings with SEEG data and surgical outcomes.

Main Methods:

• Whole-brain DTI was performed on 16 epilepsy patients undergoing SEEG investigation.
• Voxel-based analysis (SPM99) was used to assess diffusion properties (ADC and FA).
• DTI data were compared to a database of 40 healthy volunteers and correlated with SEEG findings.

Main Results:

• Thirteen of 16 patients (81%) showed diffusion abnormalities on DTI.
• Increased apparent diffusion coefficient (ADC) was observed in 11 patients, correlating with SEEG-localized regions in 7.
• DTI demonstrated higher specificity in extratemporal lobe epilepsy (83%) compared to temporal lobe epilepsy (20%).

Conclusions:

• DTI can identify diffusion abnormalities potentially related to the epileptogenic zone.
• DTI findings, particularly ADC changes, showed good concordance with SEEG data, especially in extratemporal epilepsies.
• DTI shows potential as a non-invasive method for mapping the epileptogenic network and aiding surgical planning in epilepsy.