Nuclear Medicine Subdivision, Department of Imaging and Pathology, University Hospital Leuven, Leuven, Belgium
Department of Neurology, Sean M. Healey and AMG Center for ALS, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
J Nucl Med. 2020 Nov;61(11):1621-1627. doi: 10.2967/jnumed.119.241059. Epub 2020 Mar 13.
Neuroinflammation has been implicated in amyotrophic lateral sclerosis (ALS) and can be visualized using translocator protein (TSPO) radioligands. To become a reliable pharmacodynamic biomarker for ALS multicenter trials, TSPO radioligands have some challenges to overcome. We aimed to investigate whether multicenter data pooling of different TSPO tracers (C-PBR28 and F-DPA714) is feasible, after validation of an established C-PBR28 PET pseudo reference analysis technique for F-DPA714. Seven ALS patients from Belgium (58.9 ± 6.7 y old, 5 men and 2 women), 8 healthy volunteers from Belgium (52.1 ± 15.2 y old, 3 men and 5 women), 7 ALS patients from the United States (53.4 ± 9.8 y old, 5 men and 2 women), and 7 healthy volunteers from the United States (54.6 ± 9.6 y old, 4 men and 3 women) from a previously published study underwent dynamic F-DPA714 (Leuven, Belgium) or C-PBR28 (Boston, Massachusetts) PET/MRI. For F-DPA714, maps of total volume of distribution (V) were compared with SUV ratio (SUVR) images from 40 to 60 min after injection (SUVR) calculated using the pseudo reference regions cerebellum, occipital cortex, and whole brain (WB) without ventricles. For C-PBR28, SUVR images from 60 to 90 min after injection using the WB without ventricles were calculated. In line with previous studies, increased F-DPA714 uptake (17.0% ± 5.6%) in primary motor cortices was observed in ALS subjects, as measured by both V and SUVR approaches. The highest sensitivity was found for SUVR calculated using the WB without ventricles (average cluster, 21.6% ± 0.1%). F-DPA714 V ratio was highly correlated with the SUVR ( > 0.8, < 0.001). A similar pattern of increased uptake (average cluster, 20.5% ± 0.5%) in the primary motor cortices was observed in ALS subjects for C-PBR28 SUVR calculated using the WB without ventricles. Analysis of the F-DPA714 and C-PBR28 data together resulted in a more extensive pattern of significantly increased glial activation bilaterally in the primary motor cortices. The same pseudo reference region analysis technique for C-PBR28 PET can be extended toward F-DPA714 PET. Therefore, in ALS, standardized analysis across these 2 tracers enables pooling of TSPO PET data across multiple centers and increases the power of TSPO as a biomarker for future therapeutic trials.
神经炎症与肌萎缩侧索硬化症(ALS)有关,可以使用转位蛋白(TSPO)放射性配体进行可视化。为了成为 ALS 多中心试验的可靠药效学生物标志物,TSPO 放射性配体仍面临一些需要克服的挑战。我们旨在通过验证用于 F-DPA714 的已建立的 C-PBR28 PET 伪参考分析技术,来研究不同 TSPO 示踪剂(C-PBR28 和 F-DPA714)的多中心数据汇总是否可行。 先前研究中,来自比利时的 7 名 ALS 患者(58.9 ± 6.7 岁,5 名男性和 2 名女性)、来自比利时的 8 名健康志愿者(52.1 ± 15.2 岁,3 名男性和 5 名女性)、来自美国的 7 名 ALS 患者(53.4 ± 9.8 岁,5 名男性和 2 名女性)和来自美国的 7 名健康志愿者(54.6 ± 9.6 岁,4 名男性和 3 名女性)接受了动态 F-DPA714(比利时鲁汶)或 C-PBR28(马萨诸塞州波士顿)PET/MRI。对于 F-DPA714,将总分布容积(V)图与注射后 40 至 60 分钟(SUV)计算的 SUV 比(SUVR)图像进行比较,使用伪参考区域小脑、枕叶皮质和整个大脑(WB)而无脑室。对于 C-PBR28,使用无脑室的 WB 计算注射后 60 至 90 分钟的 SUVR 图像。 与之前的研究一致,在 ALS 患者中观察到原发性运动皮质中 F-DPA714 摄取增加(17.0% ± 5.6%),通过 V 和 SUVR 方法均可测量。使用无脑室 WB 计算的 SUVR 方法的灵敏度最高(平均簇,21.6% ± 0.1%)。F-DPA714 V 比与 SUVR 高度相关(>0.8,<0.001)。在 ALS 患者中,C-PBR28 SUVR 使用无脑室 WB 计算时,原发性运动皮质中摄取增加(平均簇,20.5% ± 0.5%)的类似模式。F-DPA714 和 C-PBR28 数据的联合分析导致双侧原发性运动皮质中胶质激活的广泛增加。 对于 C-PBR28 PET,可以扩展相同的伪参考区域分析技术,以扩展到 F-DPA714 PET。因此,在 ALS 中,这两种示踪剂的标准化分析能够跨多个中心汇总 TSPO PET 数据,并提高 TSPO 作为未来治疗试验生物标志物的功效。