Department of Radiology and Biomedical Imaging, Yale School of Medicine, 801 Howard Avenue, PO Box 208048, New Haven, CT, 06520- 8048, USA.
Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut, USA.
Eur J Nucl Med Mol Imaging. 2024 Dec;52(1):113-121. doi: 10.1007/s00259-024-06885-6. Epub 2024 Aug 19.
[F]SynVesT-1, a positron emission tomography (PET) radiotracer for the synaptic vesicle glycoprotein 2A (SV2A), demonstrates kinetics similar to [C]UCB-J, with high brain uptake, fast kinetics fitting well with the one-tissue compartment (1TC) model, and excellent test-retest reproducibility. Challenges arise due to the similarity between k and [Formula: see text] (efflux rate of the reference region), when applying the simplified reference tissue model (SRTM) and related methods in [C]UCB-J studies to accurately estimate [Formula: see text]. This study evaluated the suitability of these methods to estimate [F]SynVesT-1 binding using centrum semiovale (CS) or cerebellum (CER) as reference regions.
Seven healthy participants underwent 120-min PET scans on the HRRT scanner with [F]SynVesT-1. Six participants underwent test and retest scans. Arterial blood sampling and metabolite analysis provided input functions for the 1TC model, serving as the gold standard for kinetic parameters values. SRTM, coupled SRTM (SRTMC) and SRTM2 estimated were applied to estimate [Formula: see text](ref: CS) and DVR(ref: CER) values. For SRTM2, the population average of [Formula: see text] was determined from the 1TC model applied to the reference region. Test-retest variability and minimum scan time were also calculated.
The 1TC k (1/min) values for CS and CER were 0.031 ± 0.004 and 0.021 ± 0.002, respectively. Although SRTMC [Formula: see text] was much higher than 1TC [Formula: see text], SRTMC underestimated BP(ref: CS) and DVR by an average of 3% and 1% across regions, respectively, due to similar bias in k and [Formula: see text] estimation. SRTM underestimated BP(ref: CS) by an average of 3%, but with the CER as reference region, SRTM estimation was unstable and DVR underestimation varied by region (mean 10%). Using population average [Formula: see text] values, SRTM2 BP and DVR showed the best agreement with 1TC estimates.
Our findings support the use of population [Formula: see text] value in SRTM2 with [F]SynVesT-1 for the estimation of [Formula: see text] or DVR, regardless of the choice of reference region.
[F]SynVesT-1 是一种正电子发射断层扫描（PET）示踪剂，用于突触囊泡糖蛋白 2A（SV2A），其动力学与 [C]UCB-J 相似，具有高脑摄取率，快速动力学与单组织室（1TC）模型拟合良好，且具有出色的复测重现性。当在 [C]UCB-J 研究中应用简化参考组织模型（SRTM）和相关方法来准确估计 [Formula: see text] 时，由于 k 和 [Formula: see text]（参考区域流出率）之间的相似性，会出现一些挑战。本研究评估了使用半卵圆中心（CS）或小脑（CER）作为参考区域，这些方法是否适合估计 [F]SynVesT-1 结合。
七名健康参与者在 HRRT 扫描仪上进行了 120 分钟的 [F]SynVesT-1 PET 扫描。六名参与者接受了测试和复测扫描。动脉采血和代谢物分析为 1TC 模型提供了输入函数，作为动力学参数值的金标准。应用 SRTM、耦合 SRTM（SRTMC）和 SRTM2 估计来估计 [Formula: see text]（参考：CS）和 DVR（参考：CER）值。对于 SRTM2，通过将 1TC 模型应用于参考区域来确定参考区域中 [Formula: see text] 的群体平均值。还计算了复测变异性和最小扫描时间。
CS 和 CER 的 1TC k（1/min）值分别为 0.031±0.004 和 0.021±0.002。尽管 SRTMC [Formula: see text] 远高于 1TC [Formula: see text]，但由于 k 和 [Formula: see text] 估计的相似偏差，SRTMC 平均低估了 BP（参考：CS）和 DVR 分别为 3%和 1%。SRTM 平均低估了 BP（参考：CS）的 3%，但当 CER 作为参考区域时，SRTM 估计不稳定，且 DVR 低估因区域而异（平均为 10%）。使用群体平均 [Formula: see text] 值，SRTM2 的 BP 和 DVR 与 1TC 估计值具有最佳一致性。
我们的研究结果支持在 [F]SynVesT-1 中使用群体 [Formula: see text] 值和 SRTM2 来估计 [Formula: see text] 或 DVR，无论选择哪种参考区域。
