Postoperative recovery of hippocampal contralateral diffusivity in medial temporal lobe epilepsy.
OBJECTIVE
To search for a recovery after surgery of mean diffusivity (MD) values in the contralateral nonsclerotic hippocampus of patients with medial temporal lobe epilepsy (MTLE) and hippocampal sclerosis (HS).


METHODS
Twenty-four MTLE patients (12 right-sided and 12 left-sided MTLE) and 36 healthy volunteers were investigated using diffusion tensor imaging. A region-of-interest approach was used to measure pre- and postoperative interictal hippocampal MD values in patients.


RESULTS
Diffusion abnormalities in contralateral nonsclerotic hippocampus recovered after surgery (p<0.0001). A subgroup of 14 patients exhibited a clear increase in MD values whereas the remaining 10 patients were stable. No significant difference was found between the two subgroups for each of the electroclinical data studied including early postoperative outcome, all patients being either seizure free or with rare persistent auras.


CONCLUSIONS
This finding suggests that diffusion abnormalities in contralateral hippocampus may represent a functional mechanism linked to the active epileptic process.
Thivard
Lionel
L
Epileptology Unit, Hôpital de la Salpêtrière, Paris, France. lionel.thivard@psl.ap-hop-paris.fr
Tanguy
Marie-Laure
ML
Adam
Claude
C
Clémenceau
Stéphane
S
Dezamis
Edouard
E
Lehéricy
Stéphane
S
Dormont
Didier
D
Chiras
Jacques
J
Baulac
Michel
M
Dupont
Sophie
S
D000328:Adult; D038524:Diffusion Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D018572:Disease-Free Survival; D004833:Epilepsy, Temporal Lobe / Q000473:pathology / Q000601:surgery*; D005260:Female; D007839:Functional Laterality; D006624:Hippocampus / Q000473:pathology* / Q000601:surgery* / Q000648:ultrastructure; D006801:Humans; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D012598:Sclerosis / Q000473:pathology; D016896:Treatment Outcome