title: SISCOM and FDG-PET in patients with non-lesional extratemporal epilepsy: correlation with intracranial EEG, histology, and seizure outcome.
abstract: OBJECTIVE
  To assess the practical localising value of subtraction ictal single-photon emission computed tomography (SISCOM) coregistered with MRI and (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) in patients with extratemporal epilepsy and normal MRI.
  
  
  METHODS
  We retrospectively studied a group of 14 patients who received surgery due to intractable epilepsy and who were shown to have focal cortical dysplasia, undetected by MRI, based on histological investigation. We coregistered preoperative SISCOM and PET images with postoperative MRI and visually determined whether the SISCOM focus, PET hypometabolic area, and cerebral cortex, exhibiting prominent abnormalities on intracranial EEG, were removed completely, incompletely, or not at all. These results and histopathological findings were compared with postoperative seizure outcome.
  
  
  RESULTS
  Two patients underwent one-stage multimodal image-guided surgery and the remaining 12 underwent long-term invasive EEG. SISCOM findings were localised for all but 1 patient. FDG-PET was normal in 3 subjects, 2 of whom had favourable postsurgical outcome (Engel class I and II). Complete resection of the SISCOM focus (n=3), the area of PET hypometabolism (n=2), or the cortical regions with intracranial EEG abnormalities (n=7) were predictive of favourable postsurgical outcome. Favourable outcome was also encountered in: 4 of 8 patients with incomplete resection and 1 of 2 with no resection of the SISCOM focus; 4 of 7 patients with incomplete resection and 1 of 2 with no resection of the PET hypometabolic area; and 2 of 7 patients with incomplete resection of the area corresponding to intracranial EEG abnormality. No correlation between histopathological FCD subtype and seizure outcome was observed.
  
  
  CONCLUSIONS
  Complete resection of the dysplastic cortex localised by SISCOM, FDG-PET or intracranial EEG is a reliable predictor of favourable postoperative seizure outcome in patients with non-lesional extratemporal epilepsy.
authors.affiliation: Department of Pediatric Neurology, Charles University, 2nd Faculty of Medicine, University Hospital Motol, Czech Republic.
authors.forename: Martin
authors.initials: M
authors.lastname: Kudr
authors.forename: Pavel
authors.initials: P
authors.lastname: Krsek
authors.forename: Petr
authors.initials: P
authors.lastname: Marusic
authors.forename: Martin
authors.initials: M
authors.lastname: Tomasek
authors.forename: Jiri
authors.initials: J
authors.lastname: Trnka
authors.forename: Katerina
authors.initials: K
authors.lastname: Michalova
authors.forename: Monika
authors.initials: M
authors.lastname: Jaruskova
authors.forename: Jan
authors.initials: J
authors.lastname: Sanda
authors.forename: Martin
authors.initials: M
authors.lastname: Kyncl
authors.forename: Josef
authors.initials: J
authors.lastname: Zamecnik
authors.forename: Jan
authors.initials: J
authors.lastname: Rybar
authors.forename: Alena
authors.initials: A
authors.lastname: Jahodova
authors.forename: Milan
authors.initials: M
authors.lastname: Mohapl
authors.forename: Vladimir
authors.initials: V
authors.lastname: Komarek
authors.forename: Michal
authors.initials: M
authors.lastname: Tichy
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D001931:Brain Mapping / Q000379:methods; D002648:Child; D004569:Electroencephalography; D004827:Epilepsy / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011877:Radionuclide Imaging; D012189:Retrospective Studies; D025321:Surgery, Computer-Assisted; D016896:Treatment Outcome
keywords: MRI-negative epilepsy; PET; epilepsy surgery; focal cortical dysplasia; ictal SPECT