A structural MRI study: gray matter changes in mesial temporal lobe epilepsy patients with different seizure types

Abstract

Objective To observe gray matter volume changes and evaluate the relation between gray matter changes and duration of mesial temporal lobe epilepsy (mTLE) patients with different seizure types.  Methods A total of 40 patients with mTLE, including 20 with partial seizures (mTLE-PS group) and 20 with secondarily generalized seizures (mTLE-sGS group), and 20 sex- and age-matched healthy volunteers (control group) were recruited.  T₁-three-dimensional magnetization-prepared rapid gradient echo (T₁-3D-MPRAGE) was scanned for voxel.based morphometry (VBM). Bilateral frontal lobes and thalami were selected as regions of interest (ROIs) to compare gray matter volume of brain regions among 3 groups. Spearman rank correlation analysis was used to evaluate the correlation between gray matter volume of brain regions and duration.  Results There were significant differences in gray matter volumes in bilateral superior frontal gyri, right middle frontal gyrus, right medial frontal gyrus, right angular gyrus, right middle temproral gyrus, right hippocampus, bilateral thalami and bilateral cerebellar hemispheres among 3 groups (P < 0.01, for all; FWE correction). Compared with control group, gray matter volumes in bilateral superior frontal gyri, bilateral cerebellar hemispheres, right middle temproral gyrus, right hippocampus and right thalamus in mTLE-PS group were significantly decreased (P < 0.01, for all; FWE correction). Compared with control group, gray matter volumes in bilateral superior frontal gyri, bilateral thalami, bilateral cerebellar hemispheres, right angular gyrus, right middle temporal gyrus and right hippocampus in mTLE-sGS group were significantly decreased (P < 0.01, for all; FWE correction). Compared with mTLE-PS group, gray matter volumes in bilateral superior frontal gyri, bilateral thalami, right medial frontal gyrus and right gyrus rectus in mTLE-sGS group were significantly reduced (P < 0.01, for all; FWE correction). Gray matter volumes in left superior frontal gyrus (r_s = -0.611, P = 0.004) and right middle frontal gyrus (r_s = -0.562, P = 0.010) were negatively correlated with duration in mTLE-sGS group.  Conclusions mTLE patients with different seizure types have revealed multiple gray matter damages in bilateral frontal lobes, thalami and cerebellar hemispheres, and right temporal lobe and hippocampus, but there is a difference in the injured brain regions. Bilateral frontal lobes and thalami atrophy in secondarily generalized seizures of mTLE show that thalamocortical circuit plays an important role in secondarily generalied seizures of mTLE.

DOI: 10.3969/j.issn.1672-6731.2018.03.004