MR Imaging Findings in a Large Population of Autoimmune Encephalitis

Proposed imaging stratification algorithm for patients with suspected AIE. Boldface antibodies belong to the group 1 classification.

Imaging findings in examples of group 1 antibody AIE. A, A 65-year-old woman with a history of ovarian cancer who developed emesis, ataxia, and gait instability. Axial FLAIR images demonstrate enlarged cerebellar folia (large white arrow), compatible with volume loss. Subsequent work-up revealed anti-Yo encephalitis. B, A 44-year-old woman with 9 months of progressive ophthalmoplegia, amnesia, mild hemiparesis, and vertigo. Axial FLAIR imaging demonstrates deep gray and periventricular white matter hyperintensity (white arrows). The patient was subsequently diagnosed with anti-CV2 encephalitis.

A 22-year-old man with no major medical history presented with subacute, progressive, altered mental status and psychiatric symptoms including paranoia and visual and auditory hallucinations. He subsequently developed memory loss and aphasia and was ultimately diagnosed with anti-NMDA receptor encephalitis. Axial FLAIR images of the patient at 2 different levels are shown. A, At the level of the temporal horns, there is FLAIR hyperintensity and swelling of bilateral hippocampi and medial temporal lobes (white arrows). B, At the level of the lateral ventricular bodies, there is FLAIR hyperintensity and swelling of the right insular and superior temporal cortices (thin white arrows), as well as the right caudate head and putamen (white arrowhead).

A 43-year-old woman with progressive, altered mental status and right-leg and buttock paresthesia. Subsequent testing revealed anti-GFAP encephalitis. Axial (A) and sagittal (B) postcontrast T1-weighted imaging demonstrates linear perivenular enhancement (white arrows) radiating into the periventricular white matter.