Background

Translocator protein (TSPO) PET has been used to visualize microglial activation in neuroinflammation and is a potential imaging tool for detecting autoimmune encephalitis (AIE).

Purpose

To compare the detection rate between TSPO radioligand fluorine 18 (¹⁸F) DPA-714 PET and conventional MRI and assess the relationship between ¹⁸F-DPA-714 uptake and clinical features in participants with AIE.

Materials and Methods

Healthy volunteers and patients with AIE were enrolled in this prospective study between December 2021 and April 2023. All participants underwent hybrid brain ¹⁸F-DPA-714 PET/MRI and antibody testing. Modified Rankin scale scoring and AIE-related symptoms were assessed in participants with AIE. Positive findings were defined as intensity of ¹⁸F-DPA-714 uptake above a threshold of the mean standardized uptake value ratio (SUVR) plus 2 SD inside the corresponding brain regions of healthy controls. The McNemar test was used to compare the positive detection rate between the two imaging modalities; the independent samples t test was used to compare continuous variables; and correlation with Bonferroni correction was used to assess the relationship between ¹⁸F-DPA-714 uptake and clinical features.

Results

A total of 25 participants with AIE (mean age, 39.24 years ± 19.03 [SD]) and 10 healthy controls (mean age, 28.70 years ± 5.14) were included. The positive detection rate of AIE was 72% (18 of 25) using ¹⁸F-DPA-714 PET compared to 44% (11 of 25) using conventional MRI, but the difference was not statistically significant (P = .065). Participants experiencing seizures exhibited significantly higher mean SUVR in the entire cortical region than those without seizures (1.23 ± 0.21 vs 1.15 ± 0.18; P = .003). Of the 13 participants with AIE who underwent follow-up PET/MRI, 11 (85%) demonstrated reduced uptake of ¹⁸F-DPA-714 accompanied by relief of symptoms after immunosuppressive treatment.

Conclusion

¹⁸F-DPA-714 PET has potential value in supplementing MRI for AIE detection.

Clinical trial registration no. NCT05293405

© RSNA, 2024

Supplemental material is available for this article.

See also the editorial by Zaharchuk in this issue.

中文翻译：

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使用 18F-DPA-714 PET/MRI 进行小胶质细胞激活成像检测自身免疫性脑炎

背景

易位蛋白 (TSPO) PET 已用于可视化神经炎症中的小胶质细胞激活，并且是检测自身免疫性脑炎 (AIE) 的潜在成像工具。

目的

^{比较 TSPO 放射性配体氟 18 ( 18} F) DPA-714 PET 和常规 MRI的检出率，并评估¹⁸ F-DPA-714 摄取与 AIE 参与者临床特征之间的关系。

材料和方法

健康志愿者和 AIE 患者于 2021 年 12 月至 2023 年 4 月期间参加了这项前瞻性研究。所有参与者均接受了混合脑¹⁸ F-DPA-714 PET/MRI 和抗体测试。对 AIE 参与者进行改良 Rankin 量表评分和 AIE 相关症状评估。阳性结果定义为¹⁸ F-DPA-714 摄取强度高于健康对照相应脑区域内平均标准化摄取值比率 (SUVR) 加上 2 SD 的阈值。 McNemar检验用于比较两种成像方式的阳性检出率；连续变量的比较采用独立样本t检验；并使用Bonferroni校正的相关性来评估¹⁸ F-DPA-714摄取与临床特征之间的关系。

结果

总共包括 25 名 AIE 参与者（平均年龄，39.24 岁 ± 19.03 [SD]）和 10 名健康对照者（平均年龄，28.70 岁 ± 5.14）。使用¹⁸ F-DPA-714 PET的 AIE 阳性检出率为 72%（25 人中的 18 人），而使用传统 MRI 的 AIE 阳性检出率为 44%（25 人中的 11 人），但差异无统计学意义（P = .065）。经历癫痫发作的参与者整个皮质区域的平均 SUVR 显着高于未癫痫发作的参与者（1.23 ± 0.21 vs 1.15 ± 0.18；P = .003）。在接受后续 PET/MRI 的 13 名 AIE 参与者中，有 11 名 (85%) 表现出¹⁸ F-DPA-714 的摄取减少，并在免疫抑制治疗后症状缓解。

结论

¹⁸ F-DPA-714 PET 在补充 MRI 检测 AIE 方面具有潜在价值。

临床试验注册号NCT05293405

© 北美放射学会，2024

本文提供了补充材料。

另请参阅本期 Zaharchuk 的社论。