title: Role of concordance between ictal-subtracted SPECT and PET in predicting long-term outcomes after epilepsy surgery.
abstract: OBJECTIVE
  F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) and ictally subtracted single photon emission tomography (iSPECT) are important for localizing the epileptogenic focus. The following study analyzes the role of inter-concordance between FDG-PET and iSPECT in predicting long-term outcomes after epilepsy surgery.
  
  
  METHODS
  We prospectively evaluated (January 2003-January 2008) patients undergoing surgery for temporal or extratemporal drug refractory epilepsy (DRE) who had at least a 5 years follow up. Patients with MRI and video EEG (vEEG) concordance for the seizure focus underwent iSPECT and FDG-PET. Concordance of the iSPECT and FDG-PET with each other and with the substrate (defined by MRI and vEEG) for temporal and extra-temporal epilepsies was evaluated and correlated with outcomes.
  
  
  RESULTS
  One hundred twenty-three patients (74 males) were included in the study (mean age at time of surgery: 18.9±10.41 years). The mean age of onset of seizures was 9.87±8.37 years. The most common semiology was complex partial (45%). When both FDG-PET and iSPECT were concordant with each other, this translated into a (class I Engel at 5 years) outcome of 62% for extra-temporal epilepsies (provided they were also concordant with the lesion, as defined by MRI and vEEG). This percentage was significant (p<0.01) compared with all other situations (both FDG-PET/iSPECT not concordant to MRI/vEEG, only PET or iSPECT concordant with MRI/vEEG). This correlation was not found for the temporal epilepsies, where the MRI and vEEG were the most important prognostic parameters. In both temporal and extratemporal epilepsies the concordance of the iSPECT/FDG-PET with the MRI/vEEG correlated with a better 5-year outcome (temporal: 70% vs 25%; extra-temporal: 62% vs 33%; p<0.05).
  
  
  CONCLUSIONS
  Concordance between non-invasive investigations iSPECT and FDG-PET is an important predictive factor for surgical outcomes in extra-temporal epilepsy.
authors.affiliation: Department of Neurosurgery, CN Centre, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India.
authors.forename: P S
authors.initials: PS
authors.lastname: Chandra
authors.affiliation: Department of Neurosurgery, CN Centre, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India.
authors.forename: Gaurang
authors.initials: G
authors.lastname: Vaghania
authors.affiliation: Department of Nuclear Medicine, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India.
authors.forename: Chandra Sekhar
authors.initials: CS
authors.lastname: Bal
authors.affiliation: Department of Nuclear Medicine, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India.
authors.forename: Madhavi
authors.initials: M
authors.lastname: Tripathi
authors.affiliation: Department of Neurosurgery, CN Centre, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India.
authors.forename: Nilesh
authors.initials: N
authors.lastname: Kuruwale
authors.affiliation: Department of Neurology, CN Centre, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India.
authors.forename: Amit
authors.initials: A
authors.lastname: Arora
authors.affiliation: Department of Neuroradiology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India.
authors.forename: Ajay
authors.initials: A
authors.lastname: Garg
authors.affiliation: Department of Pathology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India.
authors.forename: Chitra
authors.initials: C
authors.lastname: Sarkar
authors.affiliation: Department of Neurology, CN Centre, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India.
authors.forename: Rekha
authors.initials: R
authors.lastname: Diwedi
authors.affiliation: Statistician-Centre of Excellence (Epilepsy), All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India.
authors.forename: Shrividya
authors.initials: S
authors.lastname: Malviya
authors.affiliation: Department of Neurology, CN Centre, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India.
authors.forename: Vasantha
authors.initials: V
authors.lastname: Padma
authors.affiliation: Department of Neurology, CN Centre, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India. Electronic address: manjari.tripathi1@gmail.com.
authors.forename: Manjari
authors.initials: M
authors.lastname: Tripathi
mesh_terms: D000293:Adolescent; D017668:Age of Onset; D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D002648:Child; D000075202:Contraindications; D004569:Electroencephalography; D004827:Epilepsy / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008279:Magnetic Resonance Imaging; D008297:Male; D049268:Positron-Emission Tomography / Q000379:methods*; D011379:Prognosis; D011446:Prospective Studies; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D016896:Treatment Outcome; D014741:Video Recording
keywords: Epilepsy surgery; Ictal SPECT; Long-term outcomes; Multimodality; Non-invasive; PET