[18F]SynVesT-1 and [18F]FDG quantitative PET imaging in the presurgical evaluation of MRI-negative children with focal cortical dysplasia type II

Abstract

Purpose: MRI-negative children with focal cortical dysplasia type II (FCD II) are one of the most challenging cases in surgical epilepsy management. We aimed to utilize quantitative positron emission tomography (QPET) analysis to complement [¹⁸F]SynVesT-1 and [¹⁸F]FDG PET imaging and facilitate the localization of epileptogenic foci in pediatric MRI-negative FCD II patients.

Methods: We prospectively enrolled 17 MRI-negative children with FCD II who underwent [¹⁸F]SynVesT-1 and [¹⁸F]FDG PET before surgical resection. The QPET scans were analyzed using statistical parametric mapping (SPM) with respect to healthy controls. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC) of [¹⁸F]SynVesT-1 PET, [¹⁸F]FDG PET, [¹⁸F]SynVesT-1 QPET, and [¹⁸F]FDG QPET in the localization of epileptogenic foci were assessed. Additionally, we developed a multivariate prediction model based on dual trace PET/QPET assessment.

Results: The AUC values of [¹⁸F]FDG PET and [¹⁸F]SynVesT-1 PET were 0.861 (sensitivity = 94.1%, specificity = 78.2%, PPV = 38.1%, NPV = 98.9%) and 0.908 (sensitivity = 82.4%, specificity = 99.2%, PPV = 93.3%, NPV = 97.5%), respectively. [¹⁸F]FDG QPET showed lower sensitivity (76.5%) and NPV (96.6%) but higher specificity (95.0%) and PPV (68.4%) than visual assessment, while [¹⁸F]SynVesT-1 QPET exhibited higher sensitivity (94.1%) and NPV (99.1%) but lower specificity (97.5%) and PPV (84.2%). The multivariate prediction model had the highest AUC value (AUC = 0.996, sensitivity = 100.0%, specificity = 96.6%, PPV = 81.0%, NPV = 100%).

Conclusions: The multivariate prediction model based on [¹⁸F]SynVesT-1 and [¹⁸F]FDG PET/QPET assessments holds promise in noninvasively identifying epileptogenic regions in MRI-negative children with FCD II. Furthermore, the combination of visual assessment and QPET may improve the sensitivity and specificity of diagnostic tests in localizing epileptogenic foci and achieving a preferable surgical outcome in MRI-negative FCD II.

Keywords: Focal cortical dysplasia; Localization; MRI-negative epilepsy; Quantitative PET; SV2A.