Classification of structural lesions in magnetic resonance imaging. Surgical implications in drug-resistant epilepsy patients.
BACKGROUND
The presence of a structural lesion in the preoperative magnetic resonance imaging (MRI) of drug-resistant epilepsy patients has been usually associated with a favourable surgical outcome. We present our experience in our Epilepsy Surgery Unit.


METHODS
Clinical records from 265 patients, operated on from 1990-2010 in our institution, were reviewed. Patients were classified, according to MRI findings, into three groups: surgical lesion (SL), tumors or vascular malformations requiring surgery 'per se'; orientative lesion (OL), dysplasia, atrophy or mesial temporal sclerosis; and (NL) group, with normal MRI. Seizure outcomes were analysed in relation to this classification.


RESULTS
Period 1990-2000, 151 patients: 87% of SL, 65% of OL and 57% of NL patients were in Engel class I or II at the two-year follow-up. Among temporal lobe epilepsy cases (TLE), 87% of SL, 67% of OL and 56% of NL patients achieved seizure control. Differences were statistically significative. Period 2001-2010, 114 patients: 100% of SL, 90% of OL, and 81% of NL patients were in Engel's class I or II. Both TLE and extratemporal (ETLE) SL patients obtained a 100% seizure control. Among the OL patients, 95% with TLE and 43% of ETLE achieved seizure control. In the NL group, the percentages were 88% in TLE, and 50% in ETLE.


CONCLUSIONS
In our series, SL was a predictor of a favorable outcome. In TLE patients, good results were achieved despite normal MRI. Patients with ETLE and NL did not have a worse outcome than those with OL. A classification in SL, OL and NL seems more helpful for predicting the surgical outcome than the traditional classification lesion versus non-lesion MRI. Radiological findings must be carefully evaluated in the context of a complete epilepsy surgery evaluation.
Hospital Universitario de la Princesa, 28006 Madrid, Espana.
C V
CV
Torres
J
J
Pastor
E
E
Garcia-Navarrete
P
P
Pulido-Rivas
R G
RG
Sola
D000328:Adult; D000927:Anticonvulsants / Q000627:therapeutic use; D001284:Atrophy; D001921:Brain / Q000473:pathology* / Q000601:surgery; D001930:Brain Injuries / Q000150:complications / Q000473:pathology / Q000601:surgery; D001932:Brain Neoplasms / Q000150:complications / Q000473:pathology / Q000601:surgery; D020785:Central Nervous System Vascular Malformations / Q000150:complications / Q000473:pathology / Q000601:surgery; D004351:Drug Resistance; D000069279:Drug Resistant Epilepsy / Q000188:drug therapy / Q000209:etiology / Q000473:pathology* / Q000601:surgery; D004569:Electroencephalography / Q000379:methods; D004660:Encephalitis / Q000150:complications / Q000473:pathology; D004828:Epilepsies, Partial / Q000188:drug therapy / Q000209:etiology / Q000473:pathology / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D054220:Malformations of Cortical Development / Q000150:complications / Q000473:pathology / Q000601:surgery; D008581:Meningitis / Q000150:complications / Q000473:pathology; D008875:Middle Aged; D009460:Neurologic Examination; D011183:Postoperative Complications / Q000473:pathology; D011379:Prognosis; D016896:Treatment Outcome; D014402:Tuberous Sclerosis / Q000150:complications / Q000473:pathology / Q000601:surgery; D055815:Young Adult
D000927:Anticonvulsants