title: Application of an objective method for localizing bilateral cortical FDG PET abnormalities to guide the resection of epileptic foci.
abstract: OBJECTIVE
  In order to improve the objective localization of bilateral cortical abnormalities in positron emission tomography (PET) image volumes, we developed a new three-dimensional image processing technique. The accuracy of this approach with respect to invasive subdural electroencephalography (EEG) data was assessed in a group of children with neocortical epilepsy.
  
  
  METHODS
  Glucose PET image volumes were obtained from 12 epileptic children (mean age 5.2 +/- 4.3 years). Bilateral cortical areas of abnormal glucose metabolism were objectively determined using two conditional criteria assessed against a normal database. The normal database was derived from a group of 15 adult controls (mean age 27.6 years). The spatial relationship between seizure onset electrodes and PET abnormalities was assessed using a conventional receiver operating characteristic (ROC) analysis as well as using a newly defined spatial proximity index (SPI), which characterizes the association between adjacent, but not coincident, abnormalities.
  
  
  RESULTS
  ROC analysis at the 2 standard deviation (SD) threshold, revealed an accuracy of 65% to detect seizure onset areas with a sensitivity of 64 +/- 17% and a specificity of 66 +/- 24%. Sensitivity decreased to 46 +/- 24% at the 3-SD threshold with a specificity of 80 +/- 21% (accuracy 75%). The average value for the SPI was determined as 3.82 +/- 1.65 which was 20% lower than the SPI value calculated using a simple in-plane two-dimensional asymmetry between homotopic cortical segments (4.52 +/- 3.82).
  
  
  CONCLUSIONS
  The presented image processing technique improves localization of cortical abnormalities and provides valuable imaging clues for placement of subdural EEG grids prior to surgical resection.
authors.affiliation: Department of Pediatrics and Radiology, Children's Hospital of Michigan, 3901 Beaubien Blvd, Detroit, MI 48201, USA. otto@pet.wayne.edu
authors.forename: Otto
authors.initials: O
authors.lastname: Muzik
authors.forename: Siamak
authors.initials: S
authors.lastname: Pourabdollah
authors.forename: Csaba
authors.initials: C
authors.lastname: Juhasz
authors.forename: Diane C
authors.initials: DC
authors.lastname: Chugani
authors.forename: James
authors.initials: J
authors.lastname: Janisse
authors.forename: Sorin
authors.initials: S
authors.lastname: Draghici
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D001921:Brain / Q000000981:diagnostic imaging / Q000601:surgery; D002675:Child, Preschool; D004827:Epilepsy / Q000000981:diagnostic imaging* / Q000601:surgery*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007223:Infant; D008297:Male; D010363:Pattern Recognition, Automated / Q000379:methods; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D025321:Surgery, Computer-Assisted / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18