Voxel-based statistical analysis of fractional anisotropy and mean diffusivity in patients with unilateral temporal lobe epilepsy of unknown cause.
OBJECTIVE
To determine regional alterations of fractional anisotropy (FA) and mean diffusivity (MD) in patients with magnetic resonance imaging (MRI)-negative temporal lobe epilepsy with unknown cause (TLEu) using diffusion tensor imaging (DTI) and voxel-based statistics (VBS).


METHODS
Ten patients with left TLEu and no abnormality on conventional MRI and 81 age-matched neurological healthy controls were studied. VBS analyses were used to compare FA and MD differences between patients and controls. All results were reported using stringent statistical thresholds corrected for multiple comparisons.


RESULTS
Patients with TLEu had widespread and bilateral reduction of white matter FA, encompassing the temporal lobes, entire corpus callosum, thalamus, and other regions relative to controls. Increased MD was more spatially limited in patients, but was also observed in the thalamus. FA of the putamen was significantly increased bilaterally in patients relative to controls, which correlated with increasing macroscopic atrophy of the putamen.


CONCLUSIONS
Water diffusion abnormalities are widespread and bilaterally distributed in patients with unilateral TLEu, which are beyond the resolution of conventional MRI. FA alterations are more widespread relative to MD alterations. This is the first study to show evidence of interrelated microscopic (ie, FA increase) and macroscopic (ie, atrophy) alterations of the putamen in patients with TLEu.
Department of Neurology, University of Münster, Germany.
Simon S
SS
Keller
Tobias
T
Ahrens
Siawoosh
S
Mohammadi
Jan S
JS
Gerdes
Gabriel
G
Möddel
Christoph
C
Kellinghaus
Harald
H
Kugel
Bernd
B
Weber
E Bernd
EB
Ringelstein
Michael
M
Deppe
D000328:Adult; D000465:Algorithms; D016880:Anisotropy; D003627:Data Interpretation, Statistical; D004058:Diffusion; D056324:Diffusion Tensor Imaging / Q000379:methods*; D004833:Epilepsy, Temporal Lobe / Q000473:pathology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity