title: FDG-PET improves surgical outcome in negative MRI Taylor-type focal cortical dysplasias.
abstract: OBJECTIVE
  To determine the diagnostic accuracy and prognostic value of ¹⁸FDG-PET in a recent series of patients operated for intractable partial epilepsy associated with histologically proven Taylor-type focal cortical dysplasia (TTFCD) and negative MRI.
  
  
  METHODS
  Of 23 consecutive patients (12 male, 7-38 years old) with negative 1.5-Tesla MRI, 10 exhibited subtle nonspecific abnormalities (e.g., unusual sulcus depth or gyral pattern) and the 13 others had strictly normal MRI. FDG-PET was analyzed both visually after coregistration on MRI and using SPM5 software. Metabolic data were compared with the epileptogenic zone (EZ) determined by stereo-EEG (SEEG) and surgical outcome.
  
  
  RESULTS
  Visual PET analysis disclosed a focal or regional hypometabolism in 18 cases (78%) corresponding to a single gyrus (n = 9) or a larger cortical region (n = 9). PET/MRI coregistration detected a partially hypometabolic gyrus in 4 additional cases. SPM5 PET analysis (n = 18) was concordant with visual analysis in 13 cases. Location of PET abnormalities was extratemporal in all cases, involving eloquent cortex in 15 (65%). Correlations between SEEG, PET/MRI, and histologic findings (n = 20) demonstrated that single hypometabolic gyri (n = 11) corresponded to EZ and TTFCD, which was localized at the bottom of the sulcus. Larger hypometabolic areas (n = 9) also included the EZ and the dysplastic cortex but were more extensive. Following limited cortical resection (mean follow-up 4 years), seizure freedom without permanent motor deficit was obtained in 20/23 patients (87%).
  
  
  CONCLUSIONS
  ¹⁸FDG-PET coregistered with MRI is highly sensitive to detect TTFCD and greatly improves diagnosis and surgical prognosis of patients with negative MRI.
authors.affiliation: Departments of Neurosurgery, Centre Hospitalier Sainte-Anne, Paris, France. f.chassoux@ch-sainte-anne.fr
authors.forename: F
authors.initials: F
authors.lastname: Chassoux
authors.forename: S
authors.initials: S
authors.lastname: Rodrigo
authors.forename: F
authors.initials: F
authors.lastname: Semah
authors.forename: F
authors.initials: F
authors.lastname: Beuvon
authors.forename: E
authors.initials: E
authors.lastname: Landre
authors.forename: B
authors.initials: B
authors.lastname: Devaux
authors.forename: B
authors.initials: B
authors.lastname: Turak
authors.forename: C
authors.initials: C
authors.lastname: Mellerio
authors.forename: J-F
authors.initials: JF
authors.lastname: Meder
authors.forename: F-X
authors.initials: FX
authors.lastname: Roux
authors.forename: C
authors.initials: C
authors.lastname: Daumas-Duport
authors.forename: P
authors.initials: P
authors.lastname: Merlet
authors.forename: O
authors.initials: O
authors.lastname: Dulac
authors.forename: C
authors.initials: C
authors.lastname: Chiron
mesh_terms: D000293:Adolescent; D000328:Adult; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery*; D004569:Electroencephalography; D004828:Epilepsies, Partial / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery*; D005260:Female; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009043:Motor Activity; D019635:Neurosurgical Procedures / Q000379:methods; D049268:Positron-Emission Tomography; D011379:Prognosis; D019275:Radiopharmaceuticals; D012640:Seizures / Q000473:pathology / Q000601:surgery; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18