To explore the characteristics of head MRI of anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis.

The general data and head MRI results of 12 patients with anti-NMDAR encephalitis who were diagnosed and treated in the Neurology Department of Beijing Chaoyang Integrative Medicine Emergency Medical Center from December 2018 to June 2020 were collected and retrospectively analyzed.

Head MRI results of the 12 patients: normal in 4 cases (33.3%), abnormal in 8 cases (66.7%), the lesions were single or multiple, flaky or patchy, with blurred borders. Lesion location: medial temporal lobe 6 cases (75.0%), insular lobe 4 cases (50.0%), frontal lobe 3 cases (37.5%). Abnormal sequence: 2 cases (25.0%) with low signal on T1WI, 6 cases (75.0%) with high signal on T2WI, 8 cases (100%) with high signal on FLAIR, and 3 cases (37.5%) with high signal on DWI. There were 3 cases (37.5%) with enhancement, the specific manifestations were punctate and flocculent enhancement in the lesion area, part of the pia mater and adjacent blood vessels.

Although head MRI imaging can not be used as a specific indicator for the diagnosis of anti-NMDAR encephalitis, the possibility of anti NMDAR encephalitis should be highly vigilant when the lesions appear in the medial temporal lobe and (or) the insular lobe, are flaky or patchy, with blurred borders, high signal intensity on FLAIR and (or) T2WI and partial enhancement.