title: Comparative Study of Voxel-Based Epileptic Foci Localization Accuracy between Statistical Parametric Mapping and Three-dimensional Stereotactic Surface Projection.
abstract: BACKGROUND
  Fluorine-18-fluorodeoxyglucose positron-emission tomography (18F-FDG-PET) is widely used to help localize the hypometabolic epileptogenic focus for presurgical evaluation of drug-refractory epilepsy patients. Two voxel-based brain mapping methods to interpret18F-FDG-PET, statistical parametric mapping (SPM) and three-dimensional stereotactic surface projection (3D-SSP), improve the detection rate of seizure foci. This study aimed to compare the consistency of epileptic focus detection between SPM and 3D-SSP for18F-FDG-PET brain mapping analysis.
  
  
  METHODS
  We retrospectively reviewed the clinical, electroecephalographic, and brain imaging results of 35 patients with refractory epilepsy.18F-FDG-PET studies were revaluated by SPM, 3D-SSP, and visual assessment, and the results were compared to the magnetic resonance imaging (MRI) lesion location and to the presumed epileptogenic zone (PEZ) defined by video-electroencephalogram and other clinical data. A second consistency study compared PET analyses to histopathology and surgical outcomes in the 19 patients who underwent lesion resection surgery.
  
  
  RESULTS
  Of the 35 patients, consistency with the PEZ was 29/35 for SPM, 25/35 for 3D-SSP, 14/35 for visual assessment, and 10/35 for MRI. Concordance rates with the PEZ were significantly higher for SPM and 3D-SSP than for MRI (P< 0.05) and visual assessment (P< 0.05). Differences between SPM and 3D-SSP and between visual assessment and MRI were not significant. In the 19 surgical patients, concordance with histopathology/clinical outcome was 14/19 for SPM, 15/19 for 3D-SSP, 14/19 for visual assessment, and 9/19 for MRI (P> 0.05). A favorable Engel outcome (class I/II) was found in 16 of 19 cases (84%), and failure of seizure control was found in 3 of 19 patients (class III/IV).
  
  
  CONCLUSIONS
  Voxel-based18F-FDG-PET brain mapping analysis using SPM or 3D-SSP can improve the detection rate of the epileptic focus compared to visual assessment and MRI. Consistency with PEZ was similar between SPM and 3D-SSP; according to their own characteristics, 3D-SSP is recommended for primary evaluation due to greater efficiency and operability of the software, while SPM is recommended for high-accuracy localization of complex lesions. Therefore, joint application of both software packages may be the best solution for FDG-PET analysis of epileptic focus localization.
authors.affiliation: Beijing Neurosurgical Institute, Capital Medical University, Beijing, China; Beijing Key Laboratory of Neurostimulation, Beijing, China.
authors.forename: Kailiang
authors.initials: K
authors.lastname: Wang
authors.affiliation: Beijing Neurosurgical Institute, Capital Medical University, Beijing, China; Beijing Key Laboratory of Neurostimulation, Beijing, China.
authors.forename: Tinghong
authors.initials: T
authors.lastname: Liu
authors.affiliation: Department of Nuclear Medicine, Beijing Tiantan Hospital, Capital Medical University , Beijing , China.
authors.forename: Xiaobin
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University , Beijing , China.
authors.forename: XiaoTong
authors.initials: X
authors.lastname: Xia
authors.affiliation: Beijing Key Laboratory of Neurostimulation, Beijing, China; Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Zhang
authors.affiliation: Beijing Neurosurgical Institute, Capital Medical University , Beijing , China.
authors.forename: Hui
authors.initials: H
authors.lastname: Qiao
authors.affiliation: Beijing Key Laboratory of Neurostimulation, Beijing, China; Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
authors.forename: Jianguo
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Beijing Neurosurgical Institute, Capital Medical University, Beijing, China; Beijing Key Laboratory of Neurostimulation, Beijing, China.
authors.forename: Fangang
authors.initials: F
authors.lastname: Meng
keywords: 18F-FDG-PET; 3D-SSP; epilepsy; epileptic focus; statistical parametric mapping