Liu Mange, Li Qijun, Mao Guangjuan, Zhu Yicheng, Cui Ruixue, Guan Hongzhi
Department of Neurology, Peking Union Medical College Hospital, Shuaifuyuan, Wangfujing Street, Beijing, 100730, China.
Department of Nuclear Medicine, Peking Union Medical College Hospital, Shuaifuyuan, Wangfujing Street, Beijing, 100730, China.
Cerebellum. 2025 Jul 12;24(5):130. doi: 10.1007/s12311-025-01888-x.
Brain magnetic resonance imaging (MRI) often appears normal in patients with autoimmune cerebellar ataxia (ACA), whereas case studies indicate [F]fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) can detect abnormal metabolic patterns in these patients. This study aims to evaluate the brain FDG-PET characteristics of ACA, assess its clinical correlations and diagnostic utility.
55 ACA patients and 28 age and sex-matched healthy controls were included. PET results were evaluated using both visual analysis and voxel-based analysis.
Before immunotherapy, FDG-PET of ACA patients typically exhibited widespread hypermetabolism, while post-treatment scans showed cerebellar hypometabolism compared to healthy controls. Patients with encephalopathy were more likely to show abnormal metabolic activity in the cerebral cortex or hippocampus. Abnormal metabolic activity in the basal ganglia was more common in patients with extrapyramidal symptoms. Relative vermis hypermetabolism was observed in 40% of patients (22/55) and was significantly associated with a lower cerebrospinal fluid white blood cell count, higher cerebellar atrophy ratio, and cerebellar hypometabolism. Overall, the sensitivity of FDG-PET (85.5%) was significantly higher than that of MRI (39.1%, p < 0.001).
Our findings demonstrate that FDG-PET is more sensitive than MRI for detecting metabolic abnormalities in ACA patients. The metabolic differences between the cerebellar vermis and the hemispheres may suggest the vulnerability of the vermis in ACA. It also provides valuable clinical correlations, identifying patterns of hyper- and hypometabolism that align with specific neurological presentations.
自身免疫性小脑共济失调（ACA）患者的脑磁共振成像（MRI）通常表现正常，而病例研究表明，[F]氟脱氧葡萄糖（FDG）正电子发射断层扫描（PET）可检测出这些患者的异常代谢模式。本研究旨在评估ACA的脑FDG-PET特征，评估其临床相关性及诊断效用。
纳入55例ACA患者及28例年龄和性别匹配的健康对照。采用视觉分析和基于体素的分析评估PET结果。
在免疫治疗前，ACA患者的FDG-PET通常表现为广泛的代谢亢进，而治疗后的扫描显示与健康对照相比小脑代谢减退。患有脑病的患者更有可能在大脑皮层或海马体出现异常代谢活动。锥体外系症状患者基底节的异常代谢活动更为常见。40%的患者（22/55）观察到小脑蚓部相对代谢亢进，且与较低的脑脊液白细胞计数、较高的小脑萎缩率和小脑代谢减退显著相关。总体而言，FDG-PET的敏感性（85.5%）显著高于MRI（39.1%，p<0.001）。
我们的研究结果表明，FDG-PET在检测ACA患者的代谢异常方面比MRI更敏感。小脑蚓部和半球之间的代谢差异可能提示ACA中蚓部的易损性。它还提供了有价值的临床相关性，确定了与特定神经学表现相符的代谢亢进和减退模式。
