Imaging features of 18F-FDG PET/CT in patients with autoimmune encephalitis / 中华核医学与分子影像杂志

ABSTRACT

Objective To study the imaging features of 18F-fluorodeoxyglucose(FDG) PET/CT in patients with autoimmune encephalitis (AE) and evaluate the value of PET/CT on early diagnosis of AE.Methods Sixteen patients with AE (11 males,5 females,age:11-68 years) between March 2012 and December 2017 were included.Patients had positive antibodies in cerebrospinal fluid or (and) serum without immunity therapy.The imaging (18F-FDG PET/CT,MRI) and clinical data were analyzed.Results Nine patients suffered from anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis and other 7 patients had limbic encephalitis (LE),which including 2 cases of anti-leucine-rich glioma inactivated 1 (LGI1) encephalitis,3 cases of anti-γ-aminobutyric acid-B receptor(GABAsR) encephalitis,1 case of anti-Hu encephalitis and 1 case of anti-Yo encephalitis.Fifteen patients showed scattered hypermetabolism or hypometabolism in the brain on PET/CT imaging,and the positive rate was 15/16.Among those patients with anti-NMDAR encephalitis,hypermetabolism in frontotemporal parietal lobes and hypometabolism in occipital lobe were shown;hypermetabolism in limbic systems including temporal lobe and hippocampus were shown in LE.No abnormal CT density was found at the same phase.Slightly higher signals on T2,fluid-attenuated inversion recovery (FLAIR) and diffusion weighted imaging (DWI) were detected in some patients,and the positive rate was 7/16.Conclusions Patients with AE of different types have different characteristics on 18F-FDG PET/CT.18F-FDG PET/CT has high positive rate for early diagnosis of AE.