Background Neuroimaging findings in autoimmune encephalitis may include normal MRI as well as limbic and extra-limbic involvement. Prompt recognition allows early immunosuppression and improved outcomes.

Methods Retrospective review of patients with Autoimmune encephalitis over the last 5 years.

Results We identified N-methyl-d-aspartate receptor (NMDAR) n=8, voltage gated potassium channel (VGKC) n=11, and leucine-rich glioma inactivated 1 (LGI1) n=11 encephalitis patients. 1/8 NMDAR encephalitis patients had abnormal MRI findings of T2 hyper intense signal in right anterior temporal and bilateral frontal and left insular lobe. DWI sequence showed restricted diffusion. 4/11 with VGKC encephalitis had positive MRI findings. Two patients had limbic involvement while one also had involvement of basal ganglia. Two patients had modest cerebral atrophy. Four patients had normal MRI findings. MRI scan was not available for three patients. 5/11 LGI1 encephalitis patients had bilateral mesial temporal lobe changes. In one patient, MRI could not be done due to permanent pacemaker. Five patients had normal MRI findings.

Conclusions In our series, 33% patients had abnormal MRI findings consistent with a diagnosis of autoimmune encephalitis, which is lower than reported in literature. High clinical suspicion should lead to prompt diagnosis even in the absence of typical encephalitic changes on MRI.