White matter abnormalities in the anterior temporal lobe suggest the side of the seizure foci in temporal lobe epilepsy.
BACKGROUND
White matter abnormalities in the anterior temporal lobe (WAATL) are sometimes observed on magnetic resonance (MR) images of patients with temporal lobe epilepsy (TLE). Our purpose was to determine whether WAATL could indicate if the seizure foci are ipsilateral on electroencephalograms (EEG) in TLE patients.


METHODS
We reviewed 112 consecutive patients with medically intractable TLE. We compared the side of seizure foci on EEG (preoperative and intraoperative) and MR images.


RESULTS
Both loss of gray-white matter demarcation and increased signal intensity changes in the anterior white matter (positive WAATL) were observed in 54 of 112 patients (48.2%) with TLE. WAATL were present on the same side as the seizure foci on preoperative intracranial EEG with subdural electrodes (iEEG) and on intraoperative electrocorticography (ECG) in all the patients. In 47 patients, MR images showed WAATL and focal lesions that were possibly epileptogenic for TLE. In 2 of the 47 patients, the seizure foci on iEEG and ECG were contralateral to the focal lesion; in the remaining 45 patients, the seizure foci on surface EEG (sEEG) and ECG and the focal lesion were on the same side. In three patients, no focal lesions were seen but WAATL were present on the same side as the seizure foci on sEEG and ECG. In four patients, MR images showed focal lesions for which epileptogenicity was questionable, and WAATL on the same side as the seizure foci on EEG.


CONCLUSIONS
WAATL are clinically useful because they indicate the side of the seizure foci.
Adachi
Y
Y
Department of Neuroradiology, Tokyo Metropolitan Neurological Hospital, 2-6-1 Musashidai, Fuchu, Tokyo 183-0042, Japan. a-yuko@fb4.so-net.ne.jp
Yagishita
A
A
Arai
N
N
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography; D004833:Epilepsy, Temporal Lobe / Q000473:pathology* / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013702:Temporal Lobe / Q000473:pathology* / Q000503:physiopathology