Brain Metabolic Alterations in Seropositive Autoimmune Encephalitis: An <sup>18</sup>F-FDG PET Study
Sébastien Bergeret,
Cristina Birzu,
Pierre Meneret,
Alain Giron,
Sophie Demeret,
Clemence Marois,
Louis Cousyn,
Laura Rozenblum,
Alice Laurenge,
Agusti Alentorn,
Vincent Navarro,
Dimitri Psimaras,
Aurélie Kas
Affiliations
Sébastien Bergeret
Sorbonne University, AP-HP, Pitié Salpêtrière-Charles Foix Hospital Group, Nuclear Medicine Department, 75013 Paris, France
Cristina Birzu
Paris Brain Institute, ICM, Sorbonne University, AP-HP, UMR S 1127, INSERM, Pitié Salpêtrière-Charles Foix Hospital Group, Service de Neurologie 2-Mazarin, 75013 Paris, France
Pierre Meneret
Nuclear Medicine Department, Eugène Marquis Centre, INSERM, LTSI-UMR 1099, 35000 Rennes, France
Sorbonne University, AP-HP, Pitié Salpêtrière-Charles Foix Hospital Group, Neurology Department, Neurological Intensive Care Unit, 75013 Paris, France
Clemence Marois
Sorbonne University, AP-HP, Pitié Salpêtrière-Charles Foix Hospital Group, Neurology Department, Neurological Intensive Care Unit, 75013 Paris, France
Louis Cousyn
Sorbonne University, AP-HP, Pitié-Salpêtrière-Charles Foix Hospital Group, Epilepsy Unit, Paris Brain Institute, ICM, Reference Center for Rare Epilepsies, 75013 Paris, France
Laura Rozenblum
Sorbonne University, AP-HP, Pitié Salpêtrière-Charles Foix Hospital Group, Nuclear Medicine Department, 75013 Paris, France
Alice Laurenge
Paris Brain Institute, ICM, Sorbonne University, AP-HP, UMR S 1127, INSERM, Pitié Salpêtrière-Charles Foix Hospital Group, Service de Neurologie 2-Mazarin, 75013 Paris, France
Agusti Alentorn
Paris Brain Institute, ICM, Sorbonne University, AP-HP, UMR S 1127, INSERM, Pitié Salpêtrière-Charles Foix Hospital Group, Service de Neurologie 2-Mazarin, 75013 Paris, France
Vincent Navarro
Sorbonne University, AP-HP, Pitié-Salpêtrière-Charles Foix Hospital Group, Epilepsy Unit, Paris Brain Institute, ICM, Reference Center for Rare Epilepsies, 75013 Paris, France
Dimitri Psimaras
Paris Brain Institute, ICM, Sorbonne University, AP-HP, UMR S 1127, INSERM, Pitié Salpêtrière-Charles Foix Hospital Group, Service de Neurologie 2-Mazarin, 75013 Paris, France
Aurélie Kas
Sorbonne University, Laboratoire d’Imagerie Biomédicale, LIB, CNRS, INSERM, AP-HP, Pitié Salpêtrière-Charles Foix Hospital Group, Nuclear Medicine Department, 75013 Paris, France
Introduction: Autoimmune encephalitis (AE) diagnosis and follow-up remain challenging. Brain 18F-fluoro-deoxy-glucose positron emission tomography (FDG PET) has shown promising results in AE. Our aim was to investigate FDG PET alterations in AE, according to antibody subtype. Methods: We retrospectively included patients with available FDG PET and seropositive AE diagnosed in our center between 2015 and 2020. Brain PET Z-score maps (relative to age matched controls) were analyzed, considering metabolic changes significant if |Z-score| ≥ 2. Results: Forty-six patients were included (49.4 yrs [18; 81]): 13 with GAD autoantibodies, 11 with anti-LGI1, 9 with NMDAR, 5 with CASPR2, and 8 with other antibodies. Brain PET was abnormal in 98% of patients versus 53% for MRI. The most frequent abnormalities were medial temporal lobe (MTL) and/or striatum hypermetabolism (52% and 43% respectively), cortical hypometabolism (78%), and cerebellum abnormalities (70%). LGI1 AE tended to have more frequent MTL hypermetabolism. NMDAR AE was prone to widespread cortical hypometabolism. Fewer abnormalities were observed in GAD AE. Striatum hypermetabolism was more frequent in patients treated for less than 1 month (p = 0.014), suggesting a relation to disease activity. Conclusion: FDG PET could serve as an imaging biomarker for early diagnosis and follow-up in AE.
