Hippocampal microstructural architecture and surgical outcome: Hippocampal diffusivity could predict seizure relapse

Area of Science:

• Neuroimaging
• Epileptology
• Neurosurgery

Background:

• Temporal lobe epilepsy with hippocampal sclerosis (TLE-HS) is a common cause of drug-resistant epilepsy.
• Understanding factors predicting surgical outcomes is crucial for patient management.
• The role of the contralateral hippocampus in seizure control post-surgery remains an area of investigation.

Purpose of the Study:

• To investigate the microstructural architecture of the contralateral hippocampus in TLE-HS patients.
• To determine the relationship between contralateral hippocampal microstructure and surgical outcomes (seizure freedom).

Main Methods:

• Included 22 TLE-HS patients and 18 healthy controls.
• Utilized pre-surgical MRI with T1-weighted and diffusion-weighted imaging.
• Segmented hippocampal subfields of the contralateral hippocampus and calculated fractional anisotropy (FA) and mean diffusivity (MD).

Main Results:

• Fifty percent of patients achieved seizure freedom (SF) post-surgery.
• Non-SF patients exhibited higher MD in the CA1, molecular layer, and dentate gyrus of the healthy hippocampus compared to SF patients.
• Lower MD values in the contralateral molecular layer and CA1 predicted long-term seizure freedom.

Conclusions:

• Contralateral hippocampal microstructure is implicated in achieving post-surgery seizure freedom in TLE-HS.
• Diffusion tensor imaging metrics of the contralateral hippocampus may serve as a predictive biomarker for surgical success.