Abstracts

Rationale: To identify abnormalities in gray, white matter concentrations (GMC, WMC) or gray matter volume (GMV) changes, and their relation to heterotopic neuron (HN) numbers in mesial temporal lobe epilepsy (mTLE).Methods: The brains of 16 left and 15 right mTLE patients who achieved an excellent surgical outcome were compared with those of 24 healthy volunteers for left mTLE group and with 23 healthy volunteers for right mTLE group, respectively, by optimized VBM using unmodulated and modulated images. HNs in the white matter of anterior temporal lobe (WMAT) were histologically counted. Results: GMCs were reduced in ipsilateral hippocampi, bilateral thalami, precentral gyri, and in cerebellum. Regional GMVs were reduced in bilateral frontopolar gyri, cingulate gyri, caudate nuclei, thalami, hippocampi, pons, and cerebellum. WMCs were reduced in ipsilateral WMAT, bilateral parahippocampal gyri, and internal capsules, but were increased in pons and bilateral precentral gyri. HN numbers of WMAT in left mTLE group showed a positive correlation (r = 0.819, p < 0.0001) with GMCs of WMAT, and a negative correlation (r = - 0.839, p < 0.0001) with the WMCs of WMAT.Conclusions: The present study shows the following in mTLE patients; abnormalities of the hippocampal-thalamo-cortical network, a GMV reduction in prefrontal lobes, an abnormality of brain tissue concentration in the pontine area, and correlations between HN numbers and GMC or WMC in WMAT. VBM results were found to correlate well with histological changes.