The quantitative analysis on location of epileptogenic zones of Focal Cortical Dysplasia based on 18F-FDGPET data

Objectives: Focal cortical dysplasia (FCD) is common intractable epilepsy whose metabolism decreases in epileptogenic zones. The present study aimed to investigate the location of epileptogenic zones of FCDbased onquantitative analysis and compare that to the visual inspection analysis additionally.

Methods: Nine FCD patients (27.89 ± 7.90 years; 6 males) and 105 healthy subjects (53.09 ± 14.36 years; 42 males) underwent brain ¹⁸FDG-PET scan.All images werenormalized and smoothed using SPM. Each voxel’s intensity was normalized to SUV by dividing mean signal of the whole-brain. First, the healthy subjects were used to establish the normal cerebral metabolic. Then, we calculated the z-score for each patient compared to healthy database to detect the significant hypometabolic area (z<-1.96). Finally, we visually inspected the relationship between these areas and the surgical resections of FCD. In addition, we compared the performance of this detection technique for the Engel I and Engel III patients.

Results: The surgical follow-up (>3 months) outcomes of 7 patients evaluated for Engel I, whereas the other 2 patients evaluated for Engel III. Among the 7 Engel I FCD, five patients’ regions from the quantitative analysiswere highly in accordance withsurgical resections. The others’regions from the quantitative analysis were mainly included inresections. However, resections on three of them were not detected by visual inspection analysis.For Engel III FCD, the surgical resections were detected by visual inspection, while the quantitative analysis detected more potential different regions in relation to FCD.

Conclusions: Thepreliminary findings suggest thatquantitative analysis can detect the epileptogenic zone which may not be inspected by visual analysis. Furthermore, quantitative analysis based on metabolismcould provide the precise location of epileptogenic zone and have potential beneficial for pre-surgical evaluation.