用于定量[(11)C]PBR28脑摄取的标准化摄取值与分布容积的比较。
Comparison of standardized uptake values with volume of distribution for quantitation of [(11)C]PBR28 brain uptake.
作者信息
Yoder Karmen K, Territo Paul R, Hutchins Gary D, Hannestad Jonas, Morris Evan D, Gallezot Jean-Dominique, Normandin Marc D, Cosgrove Kelly P
机构信息
Radiology & Imaging Sciences, Indiana University School of Medicine, Indianapolis IN; Center for Neuroimaging, Indiana University School of Medicine, Indianapolis IN; Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN.
Radiology & Imaging Sciences, Indiana University School of Medicine, Indianapolis IN.
出版信息
Nucl Med Biol. 2015 Mar;42(3):305-8. doi: 10.1016/j.nucmedbio.2014.11.003. Epub 2014 Nov 15.
INTRODUCTION
[(11)C]PBR28 is a high-affinity ligand for the Translocator Protein 18 kDa (TSPO), which is considered to be a marker for microglial activation. Volume of distribution (VT) estimated with an arterial plasma input function is the gold standard for quantitation of [(11)C]PBR28 binding. However, arterial sampling is impractical at many PET sites for multiple reasons. Reference region modeling approaches are not ideal for TSPO tracers, as the existence of a true reference region cannot be assumed. Given that it would be desirable to have a non-invasive index of [(11)C]PBR28 binding, we elected to study the utility of the semi-quantitative metric, standardized uptake value (SUV) for use in brain [(11)C]PBR PET studies. The primary goal of this study was to determine the relationship between SUV and VT.
METHODS
We performed a retrospective analysis of data from sixteen [(11)C]PBR28 PET scans acquired in baboons at baseline and at multiple time points after IV injection of lipopolysaccharide, an endotoxin that transiently induces neuroinflammation. For each scan, data from 14 brain regions of interest were studied. VT was estimated with the Logan plot, using metabolite-corrected input functions. SUV was calculated with data from 30 to 60 minutes after [(11)C]PBR28 injection.
RESULTS
Within individual PET studies, SUV tended to correlate well with VT. Across studies, the relationship between SUV and VT was variable.
CONCLUSIONS
From study to study, there was variability in the degree of correlation between [(11)C]PBR28 VT and SUV. There are multiple physiological factors that may contribute to this variance.
ADVANCES IN KNOWLEDGE
As currently applied, the non-invasive measurement of SUV does not appear to be a reliable outcome variable for [(11)C]PBR28. Additional work is needed to discover the source of the discrepancy in SUV between [(11)C]PBR28 scans.
IMPLICATIONS FOR PATIENT CARE
There is a need to develop alternatives to arterial plasma input functions for TSPO ligands in order to facilitate multi-center trials.
引言
[(11)C]PBR28是18 kDa转运蛋白（TSPO）的高亲和力配体，TSPO被认为是小胶质细胞激活的标志物。用动脉血浆输入函数估计的分布容积（VT）是定量[(11)C]PBR28结合的金标准。然而，由于多种原因，在许多PET站点进行动脉采样并不实际。参考区域建模方法对于TSPO示踪剂并不理想，因为不能假定存在真正的参考区域。鉴于希望获得[(11)C]PBR28结合的非侵入性指标，我们选择研究半定量指标标准化摄取值（SUV）在脑[(11)C]PBR PET研究中的效用。本研究的主要目标是确定SUV与VT之间的关系。
方法
我们对在狒狒身上进行的16次[(11)C]PBR28 PET扫描数据进行了回顾性分析，这些扫描在基线时以及静脉注射脂多糖（一种可短暂诱导神经炎症的内毒素）后的多个时间点进行。对于每次扫描，研究了14个脑感兴趣区域的数据。使用代谢物校正的输入函数，通过洛根图估计VT。在[(11)C]PBR28注射后30至60分钟的数据计算SUV。
结果
在个体PET研究中，SUV往往与VT具有良好的相关性。在各项研究中，SUV与VT之间的关系各不相同。
结论
在不同研究中，[(11)C]PBR28 VT与SUV之间的相关程度存在差异。有多种生理因素可能导致这种差异。
知识进展
就目前的应用情况而言，SUV的非侵入性测量似乎不是[(11)C]PBR28可靠的结果变量。需要开展更多工作来发现[(11)C]PBR28扫描之间SUV差异的来源。
对患者护理的意义
需要开发TSPO配体的动脉血浆输入函数替代方法，以促进多中心试验。
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