Yu Xinrui, Fang Yujing, Sun Lu, Yang Jingjing, Hong Jau-Shyong, Sun Bo, Wang Ying
Department of Neurology, The First Affiliated Hospital of Dalian Medical University, Dalian, China.
Neuropharmacology Section, Neurobiology Laboratory, National Institute of Environmental Health, Sciences, Research Triangle Park, Durham, NC, USA.
Quant Imaging Med Surg. 2025 Sep 1;15(9):8372-8394. doi: 10.21037/qims-2025-131. Epub 2025 Aug 19.
Imaging, particularly multimodal magnetic resonance imaging (MRI), serves as an essential auxiliary examination for diagnosing autoimmune encephalitis (AE). The diversity of autoantibodies complicates the imaging presentation of AE, exhibiting both common and individual features across different subtypes of AE. Currently, there is a lack of comprehensive studies on the imaging features of different subtypes of AE. The study aimed to explore imaging biomarkers for AE mediated by various subtypes of antibodies and clarify their significance in disease severity, treatment response, and prognosis.
The clinical and imaging data of 45 patients with AE at The First Affiliated Hospital of Dalian Medical University, collected from January 2013 to August 2022, were analyzed. Patients underwent multi-modal brain MRI. Lesion probability maps were generated, and regions of interest (ROIs) were selected based on lesion location and clinical-electroencephalographic features, for measurement of three-dimensional T1-weighted imaging (3D-T1WI), T2-weighted imaging (T2WI), T2 fluid-attenuated inversion recovery (T2 FLAIR), and apparent diffusion coefficient (ADC) sequences. These values were used for correlating with disease severity, antibody titers, response to treatment, and prognosis.
The study included 45 AE patients: 18 with anti-leucine-rich glioma inactivated protein 1 (anti-LGI1), 11 with anti-N-methyl-D-aspartate receptor (anti-NMDAR), 5 with anti-gamma-aminobutyric acid receptor B (anti-GABAR), 4 with anti-myelin oligodendrocyte glycoprotein (MOG), 4 with anti-glutamate decarboxylase 65 (anti-GAD65), and 3 with anti-contactin-associated protein-like 2 (anti-Caspr2) encephalitis. MRI abnormalities were present in 62.2% of patients, lower than that of electroencephalography (EEG) (95.6%, P<0.05). Imaging typically showed common features across different AE subtypes, predominantly involving the limbic system or regions outside of it, manifesting as T1 hypointensity, T2 FLAIR hyperintensity or mild hyperintensity, and normal or mild hyperintensity on diffusion-weighted imaging (DWI). Different AE subtypes displayed specific imaging features: anti-LGI1 encephalitis often involved 2 locations: unilateral or bilateral hippocampus or basal ganglia; anti-NMDAR encephalitis showed a low rate of imaging abnormalities, with diffuse and unfixed cortical or subcortical T2 FLAIR hyperintensity. Anti-GABAR encephalitis primarily affected the temporal lobe or hippocampus. MOG antibody cortical encephalitis exhibited cortical swelling with T2 FLAIR hyperintensity in unilateral or bilateral hemispheres, particularly in the frontal lobe. Anti-GAD65 encephalitis involved the temporal lobe/hippocampus or pontocerebellar regions. The ADC value within the ROI positively correlated with both disease severity (r=0.6891, P<0.0001) and prognosis score (r=0.8102, P<0.0001). Further analysis using receiver operating characteristic (ROC) curve and binary logistic regression indicated that the ADC value was a risk factor for poor prognosis.
Imaging abnormalities are less frequent than those detected by EEG but exhibit distinct features by subtype. Functional imaging enhances diagnostic accuracy. ADC values can serve as a crucial prognostic indicator.
影像学检查，尤其是多模态磁共振成像（MRI），是诊断自身免疫性脑炎（AE）的重要辅助检查手段。自身抗体的多样性使AE的影像学表现变得复杂，不同亚型的AE既具有共同特征，也有各自的特点。目前，对于不同亚型AE的影像学特征缺乏全面研究。本研究旨在探索由各种亚型抗体介导的AE的影像学生物标志物，并阐明其在疾病严重程度、治疗反应和预后中的意义。
分析大连医科大学附属第一医院2013年1月至2022年8月收治的45例AE患者的临床和影像学资料。患者均接受了多模态脑MRI检查。生成病变概率图，并根据病变位置和临床脑电图特征选择感兴趣区域（ROI），用于测量三维T1加权成像（3D-T1WI）、T2加权成像（T2WI）、T2液体衰减反转恢复序列（T2 FLAIR）和表观扩散系数（ADC）序列。这些值用于与疾病严重程度、抗体滴度、治疗反应和预后进行相关性分析。
本研究共纳入45例AE患者，其中抗富含亮氨酸胶质瘤失活蛋白1（anti-LGI1）脑炎18例，抗N-甲基-D-天冬氨酸受体（anti-NMDAR）脑炎11例，抗γ-氨基丁酸B受体（anti-GABAR）脑炎5例，抗髓鞘少突胶质细胞糖蛋白（MOG）脑炎4例，抗谷氨酸脱羧酶65（anti-GAD65）脑炎4例，抗接触蛋白相关蛋白样2（anti-Caspr2）脑炎3例。62.2%的患者存在MRI异常，低于脑电图（EEG）异常率（95.6%，P<0.05）。影像学检查通常显示不同AE亚型具有共同特征，主要累及边缘系统或其以外区域，表现为T1低信号、T2 FLAIR高信号或轻度高信号，扩散加权成像（DWI）上呈正常或轻度高信号。不同AE亚型具有特定的影像学特征：anti-LGI1脑炎常累及2个部位：单侧或双侧海马或基底节；anti-NMDAR脑炎的影像学异常率较低，表现为弥漫性、不固定的皮质或皮质下T2 FLAIR高信号。anti-GABAR脑炎主要累及颞叶或海马。MOG抗体相关皮质脑炎表现为单侧或双侧半球皮质肿胀伴T2 FLAIR高信号，尤其是额叶。anti-GAD65脑炎累及颞叶/海马或脑桥小脑区域。ROI内的ADC值与疾病严重程度（r=0.6891，P<0.0001）和预后评分（r=0.8102，P<0.0001）均呈正相关。采用受试者工作特征（ROC）曲线和二元逻辑回归进一步分析表明ADC值是预后不良的危险因素。
影像学异常的发生率低于EEG，但不同亚型具有明显特征。功能成像提高了诊断准确性。ADC值可作为关键的预后指标。
