Group-specific regional white matter abnormality revealed in diffusion tensor imaging of medial temporal lobe epilepsy without hippocampal sclerosis.
OBJECTIVE
In comparison to temporal lobe epilepsy (TLE) patients with hippocampal sclerosis (TLE-HS), TLE patients without HS (TLE-NH) have a similar clinical course but may result in worse surgical outcome. We investigated whether the clinical features related to the lack of HS in TLE patients (TLE-NH) can be explained by water diffusion abnormalities throughout diffusion tensor imaging (DTI) by voxel-based analysis.


METHODS
Nineteen patients with TLE-HS (left/right TLE 12:7), 18 patients with TLE-NH (left/right TLE 10:8), and 20 controls were included in the study. By statistical parametric mapping (SPM2), the diffusion properties specific to disease characteristics (TLE-HS vs. TLE-NH) were analyzed.


RESULTS
In TLE-HS, we found the areas of increased mean diffusivity (MD) in their ipsilateral temporal and extratemporal areas including the hippocampus, parahippocampal, and frontoparietal regions. Left TLE-HS showed a characteristic MD increase in the ipsilateral posterior cingulum, isthmus of corpus callosum, and contralateral occipital and temporal regions, which was not observed in right TLE-HS group. In left TLE-NH, two regions of increased MD were observed in the ipsilateral posterior fornix (within fusiform gyrus) and posterior cingulum. Right TLE-NH did not show any increased MD.


CONCLUSIONS
In left TLE-NH, we could find the water diffusion change along the posterior cingulum, which was quite different from the extensive abnormality from TLE-HS. In addition, there was a lesion-side-specific distribution (left predominant) of pathology in mesial TLE. This provides a possibility that TLE-NH is a heterogeneous or entity different from TLE-HS.
Shon
Young-Min
YM
Department of Neurology, College of Medicine, The Catholic University of Korea, Seoul, Korea.
Kim
Yeong-In
YI
Koo
Bang-Bon
BB
Lee
Jong-Min
JM
Kim
Hye J
HJ
Kim
Woo J
WJ
Ahn
Kook J
KJ
Yang
Dong W
DW
D000293:Adolescent; D000328:Adult; D038481:Anterior Temporal Lobectomy; D001284:Atrophy; D001921:Brain / Q000473:pathology / Q000503:physiopathology; D001931:Brain Mapping / Q000379:methods; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D056324:Diffusion Tensor Imaging / Q000379:methods; D004292:Dominance, Cerebral / Q000502:physiology; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis* / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D005260:Female; D006624:Hippocampus / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012598:Sclerosis; D012984:Software; D013702:Temporal Lobe / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D055815:Young Adult