Peak width of skeletonized mean diffusivity as a marker of small vessel disease in patients with temporal lobe epilepsy with hippocampal sclerosis.

Objective: White matter abnormalities in patients with temporal lobe epilepsy (TLE) and hippocampal sclerosis (HS) are well known. Peak width of skeletonized mean diffusivity (PSMD) is a novel marker for quantifying white matter integrity that may reflect small vessel disease. In this study, we aimed to quantify the extent of white matter damage in patients with TLE and HS by using PSMD.

Methods: We enrolled 52 patients with TLE with HS and 54 age- and sex-matched healthy controls. Diffusion tensor imaging (DTI) was performed using a 3-T magnetic resonance imaging scanner. We measured PSMD using DTI findings and compared PSMD between patients with TLE with HS and healthy controls. We also evaluated the correlation between PSMD and clinical factors in patients with TLE and HS.

Results: PSMD differed significantly between healthy controls and patients with TLE and HS, and it was higher in the patients (2.375 × 10 mm/s vs. 2.108 × 10 mm/s, p < .001). Furthermore, PSMD in the ipsilateral hemisphere of the HS was higher than in the contralateral hemisphere of the HS (2.472 × 10 mm/s vs. 2.258 × 10 mm/s, p = .040). PSMD was positively correlated with age (r = .512, p < .001) and age at seizure onset (r = .423, p = .002) in patients with TLE and HS.

Significance: Patients with TLE and HS had higher PSMD values than healthy controls, and PSMD was positively correlated with age. These findings provide evidence of white matter damage probably due to small vessel disease in patients with TLE and HS and support the feasibility of PSMD as a promising imaging marker for epileptic disorders.