Abstract: Objective　To investigate the clinical and imaging features of anti-N-methyl-D-aspartate receptor （anti-NMDAR） encephalitis.Methods　A total of 53 patients with anti-NMDAR encephalitis admitted to Xuanwu Hospital Capital Medical University from January to February 2015 were enrolled in this study.Their clinical and imaging features were analyzed retrospectively.Results　Among the 53 patients with anti-NMDAR encephalitis，24 were female （45.3%） and 29 were male （54.7%）．Their age ranged from 6 to 72 years with a median age of 23 years （16 cases aged <18 years and 8 cases aged >45 years）．The clinical course was 7 days to 2 years.Patients with abnormal MRI manifestation accounted for 69.8%（37/53），and abnormal signal in cerebral cortex and subcortical white matter， hippocampus， insula， cerebellum， pons， corpus callosum， basal nucleus， cingulate gyrus， thalamus were observed in 12 cases in T2 weighted image （T2WI） and fluid attenuated inversion recovery （FLAIR） sequence.Diffusion weighted imaging （DWI） was performed in ten patients，eight of whom had lightly restricted diffusion.Eleven cases underwent enhanced MRI，two of whom had lightly enhancement.Bilateral or unilateral temporal horn enlargement were shown in 33 cases，six of whom were accompanied by total brain atrophy.18F-FDG PET-CT was performed in seven cases，and three cases had cerebral hypometabolism and MRI showed brain atrophy and hippocampal atrophy.1 case underwent proton magnetic resonance spectroscopy （1H-MRS）．N-acetylaspartic acid （NAA）/creatine （Cr） decreased and choline （Cho）/Cr increased in the abnormal signal region compared with the normal brain area on the opposite side.Conclusion　Multiple brain areas，including limbic system，get involved in anti-NMDAR encephalitis.Enlarged temporal horn observed in more than 60.0% cases revealed by the first MRI examination may suggest that hippocampus was involved early before clinical onset of anti-NMDAR encephalitis.

Key words: Anti-N-methyl-D-aspartate receptor encephalitis, Hippocampus, Magnetic resonance imaging, PET-CT

摘要： 目的　分析抗N-甲基-D-天冬氨酸（NMDA）受体脑炎患者的临床、影像特点。方法　收集2015年1月—2017年2月于首都医科大学宣武医院诊治的53例抗NMDA受体脑炎患者的临床资料，分析并总结抗NMDA受体脑炎的临床特征和影像学特征。结果　53例抗NMDA受体脑炎患者中女24例（45.3%），男29例（54.7%）；年龄6~72岁（其中<18岁16例，>45岁8例），中位年龄23岁；病程7 d~2年。颅脑磁共振成像（MRI）表现异常者占69.8%（37/53），其中12例可见T2加权像（T2WI）、液体衰减反转恢复序列（FLAIR）异常信号，累及大脑皮质及皮质下白质、海马、岛叶、小脑、脑桥、胼胝体、基底核、扣带回、丘脑。10例患者行扩散加权成像（DWI），8例可见轻度扩散受限；11例行增强MRI检查，2例可见轻度强化；33例MRI检查示双侧或单侧颞角扩大，提示海马萎缩，其中6例伴全脑萎缩。7例患者行氟代脱氧葡萄糖（18F-FDG）PET-CT检查，3例显示葡萄糖代谢减低，MRI检查表现为脑萎缩、海马萎缩。1例患者行氢质子磁共振波谱（1H-MRS）检查，与对侧正常脑组织相比，异常信号区N-乙酰天冬氨酸（NAA）/肌酸（Cr）降低，胆碱（Cho）/Cr升高。结论　抗NMDA受体脑炎患者MRI检查显示包括边缘系统在内的多个脑区异常信号；首次就诊时MRI检查显示颞角扩大，提示抗NMDA受体脑炎发病前海马已受累。

关键词: 抗N-甲基-D-天冬氨酸受体脑炎, 海马, 磁共振成像, PET-CT