18F-FDG PET/CT in anti-LGI1 encephalitis: initial and follow-up findings.

Anti-LGI1 encephalitis is a subgroup of autoimmune encephalitis, characterized by memory impairments, seizures, and behavioral problems. The diagnosis can be made by clinical manifestation with a help of serum autoantibody test. There was lack of imaging studies to evaluate and monitor the disease activity by anatomical and functional information. Here, we report serial F-FDG PET/CT findings in a patient with anti-LGI1 encephalitis. Intense F-FDG uptake was initially noted in bilateral limbic system at active disease status, and then decreased and eventually normalized according to the clinical improvement after treatment. F-FDG PET/CT can be used to evaluate treatment response of encephalitis.