Developmental abnormalities of the medial temporal lobe in patients with temporal lobe epilepsy.
OBJECTIVE
To evaluate MR temporal lobe malformations and their frequency in patients with temporal lobe epilepsy.


METHODS
Two hundred twenty-two consecutive adult patients with temporal lobe epilepsy of varying severity were investigated with 1.0-T or 1.5-T MR units using three-dimensional T1-weighted acquisition protocol.


RESULTS
Sixteen patients (7.2%) presented with malformations of the temporal lobe. Four patterns of malformations were encountered: (a) heterotopia (n = 1), lining the temporal horn of the lateral ventricle; (b) focal neocortical dysgenesis (n = 6), which consisted of cortical thickening, poor gray/white matter demarcation, abnormal gyration (n = 5), or limited schizencephaly (n = 1); (c) hippocampal malformations (n = 5), which presented as abnormal hippocampal formation associated with a cyst (n = 2), isolated malformation of the subiculum (n = 1), or bilateral hippocampal malformation (n = 2) consisting of an abnormal shape and a misplaced fimbria; (d) complex malformations of the temporal lobe, combining categories a, b, and c (n = 4). The age at onset, severity of the disease, and occurrence of generalized tonicoclonic seizures were not significantly different between patients with malformations and the entire population of patients with temporal lobe epilepsy.


CONCLUSIONS
MR analysis of temporal lobe malformations allowed a precise determination of the extent of the malformations and the presence or absence of associated hippocampal disease, all of which are of great help in the preoperative evaluation of patients with intractable epilepsy.
Lehéricy
S
S
Department of Neurology, Hôpital de la Salpêtrière, Paris, France.
Dormont
D
D
Sémah
F
F
Clémenceau
S
S
Granat
O
O
Marsault
C
C
Baulac
M
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000151:congenital / Q000175:diagnosis / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D002828:Choristoma / Q000151:congenital / Q000175:diagnosis / Q000473:pathology; D004292:Dominance, Cerebral / Q000502:physiology; D004833:Epilepsy, Temporal Lobe / Q000151:congenital* / Q000175:diagnosis / Q000473:pathology; D005260:Female; D006624:Hippocampus / Q000002:abnormalities / Q000473:pathology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D013702:Temporal Lobe / Q000002:abnormalities* / Q000473:pathology