To report neuroimaging of 8 patient with autoimmune encephalitis associated with specific antibodies.

Autoimmune Encephalitis is a rare and complex group of disorders wherein the body's immune system attacks and causes inflammatory changes in the central nervous system. It presents with altered mental status and a diverse range of typical and atypical symptoms and neuroimaging and CSF findings.

Clinical data and imaging findings were obtained via retrospective chart review.

The patients in this series are mostly women (7 out 8). 5 out 8 patients are younger than 50 years old. Among the antibodies, NMDA-R antibody was identified in 4 patients while LG1, AMAP, GFAP, GAD antibodies were seen in the rest of the cases. From neuroimaging, three patients presented with significant findings. One of the NMDA-antibody encephalitis case demonstrated T2/FLAIR hyperintensity in right cerebellum. LG1-antibody encephalitis case had symmetric T2/FLAIR hyperintensity in mesial temporal lobes. One case with positive GAD antibody shows multifocal areas of confluent subcortical T2/FLAIR hyperintensity in right hemisphere which is consistent with Rasmussen’s encephalitis. The rest five patients's brain MRI were unremarkable. 

Autoimmune encephalitis may present with T2/FLAIR hyperintensities changes on MRI. The neuroimaging findings are variable depends on the antibodies type. Being familiar with the MRI findings and especially typical feature in certain type of autoimmune encephalitis will be helpful to establish diagnosis early and prompt to treatment. While normal MRI does not rule out the diagnosis especially when clinical presentation is strongly suggestive. Serum and CSF antibody testings are important lead to the ultimate diagnosis.