TSPO-PET in pre-surgical evaluations: Correlation of neuroinflammation and SEEG epileptogenicity mapping in drug-resistant focal epilepsy

• Published in: Epilepsia (Copenhagen) 2024-12
• Main Authors: Kilmer, Jennifer, Rodrigo, Sebatian, Petrescu, Ana-Maria, Aghakhani, Nozar, Herbrecht, Anne, Leroy, Claire, Tournier, Nicolas, Bottlaender, Michel, Taussig, Delphine, Bouilleret, Viviane
• Format: Article
• Language: English
• ISSN: 1528-1167; 1528-1167
• DOI: 10.1111/epi.18182

Resective surgery in drug-resistant focal epilepsy (DRFE) requires extensive evaluation to localize the epileptogenic zone (EZ). When non-invasive phase 1 assessments (electroencephalography, EEG; magnetic resonance imaging, MRI; and F-Fluorodeoxyglucose-positron emission tomography, [ F]FDG-PET) are inconclusive for EZ localization, invasive investigations such as stereo-EEG (SEEG) are necessary. Epileptogenicity maps (Ems) visualize the EZ using SEEG-identified ictal high-frequency oscillations (iHFOs). PET imaging with radioligands targeting the18-kDa translocator protein (TSPO), a marker of glial activation, may aid EZ localization. This study investigates the correlation between TSPO-PET imaging and SEEG iHFOs in DRFE to determine the utility of TSPO-PET in pre-surgical assessments, especially in complex or non-lesional cases. Patients with DRFE and inconclusive phase 1 assessments were recruited from Bicêtre Hospital (AP-HP) for a prospective study (Eudract 2017-003381-27). They underwent SEEG and [ F]DPA-714 (N,N-diethyl-2-(2-(4-(2-(fluoro- F)ethoxy)phenyl)-5,7-dimethylpyrazolo[1,5-a]pyrimidin-3-yl)acetamide) (TSPO radioligand) PET imaging. Statistical parametric mapping (SPM) techniques analyzed significant [ F]DPA-714-PET uptake (TSPO-map) and generated epileptogenicity maps (EM-map). Correlation analyses at regional and voxel-of-interest (VOI) levels assessed the relationship between TSPO-map and EM-map. We were able to obtain and analyze both maps in 12 of 17 patients recruited. A significant positive correlation between EM-map and TSPO-map in focal epilepsies was found regionally (r = .81, p