Reshtebar Niloufar, Hosseini Seyed Abolfazl, Zhuang Mingzan, Rahmim Arman, Karakatsanis Nicolas A, Sheikhzadeh Peyman
Department of Energy Engineering, Sharif University of Technology, Tehran, Iran.
Department of Nuclear Medicine, Meizhou People's Hospital, Meizhou, China.
Med Phys. 2024 Dec;51(12):9088-9102. doi: 10.1002/mp.17391. Epub 2024 Sep 28.
This simulation study investigated the feasibility of generating Patlak K images using a dual time point (DTP-K) scan protocol involving two 3-min/bed routine static PET scans and, subsequently, assessed DTP-K performance for an optimal DTP scan time frame combination, against conventional Patlak K estimated from complete 0-93 min dynamic PET data.
Six realistic heterogeneous tumors of different characteristic spatiotemporal [F]FDG uptake distributions for three noise levels commonly found in clinical studies and 20 noise realizations (N = 360 samples) were produced by analytic simulations of the XCAT phantom. Subsequently, DTP-K images were generated by performing standard linear indirect Patlak analysis with t* -min (Patlak) using a scaled population-based input function (sPBIF) model on 66 combinations of early and late 3-min/bed static whole-body PET reconstructed images. All DTP-K images were evaluated against respective DTP-K images estimated with Patlak and 0-93 min individual input functions (iIFs) and against gold standard K images estimated with Patlak, 0-93 min iIFs and tissue time activity curves from all reconstructed WB passes 12-93 min post injection. The optimal combination of early and late frames, in terms of attaining the highest correlation between DTP-K with sPBIF and gold standard K was also determined from a set of 66 different combinations of 2-min early and late frames. Moreover, the performance of DTP-K with sPBIF was compared against that of the retention index (RI) in terms of their correlation to the gold standard K. Finally, the feasibility and practicality of DTP protocol in the clinic were assessed through the analysis of nine patients.
High correlations (>0.9) were observed between DTP-K values from sPBIF and those from iIFs for all evaluated DTP protocols while the mean AUC difference between sPBIF and iIFs was less than 10%. The percentage difference of mean values between DTP-K from sPBIF and from iIFs was less than 1%. DTP K from sPBIF exhibited significantly higher correlation with gold standard K, in contrast to RI, across all 66 DTP protocols (p < 0.05 using the two-tailed t-test by Williams) with the highest correlation attained for the 50-53-min early + 90-93-min late scan time frames (optimal DTP protocol).
Feasibility of generating Patlak K [F] FDG images from an early and a late post injection 3-min/bed routine static scan using a population-based input function model was demonstrated and an optimal DTP scan protocol was determined. The results indicated high correlations between DTP-K and gold-standard K images that are significantly larger than those between RI and gold-standard K.
本模拟研究探讨了使用双时间点（DTP-K）扫描协议生成Patlak K图像的可行性，该协议包括两次3分钟/床位的常规静态PET扫描，随后针对从0至93分钟完整动态PET数据估计的传统Patlak K，评估DTP-K在最佳DTP扫描时间框架组合下的性能。
通过XCAT体模的解析模拟，针对临床研究中常见的三种噪声水平，生成了六个具有不同特征时空[F]FDG摄取分布的逼真异质性肿瘤，并进行了20次噪声实现（N = 360个样本）。随后，使用基于缩放总体的输入函数（sPBIF）模型，对早期和晚期3分钟/床位静态全身PET重建图像的66种组合，采用t* -分钟（Patlak）进行标准线性间接Patlak分析，生成DTP-K图像。所有DTP-K图像均与使用Patlak和0至93分钟个体输入函数（iIFs）估计的相应DTP-K图像进行评估，并与使用Patlak、0至93分钟iIFs以及注射后12至93分钟所有重建全身扫描的组织时间-活度曲线估计的金标准K图像进行评估。还从2分钟早期和晚期框架的66种不同组合中确定了早期和晚期框架的最佳组合，以实现DTP-K与sPBIF和金标准K之间的最高相关性。此外，就DTP-K与sPBIF和保留指数（RI）与金标准K的相关性而言，对DTP-K与sPBIF的性能进行了比较。最后，通过对九名患者的分析，评估了DTP方案在临床中的可行性和实用性。
对于所有评估的DTP方案，观察到sPBIF的DTP-K值与iIFs的DTP-K值之间具有高度相关性（>0.9），而sPBIF和iIFs之间的平均AUC差异小于10%。sPBIF的DTP-K与iIFs的平均值之间的百分比差异小于1%。与RI相比，在所有66种DTP方案中，sPBIF得到的DTP K与金标准K的相关性显著更高（使用Williams双尾t检验，p < 0.05），在50至53分钟早期 + 90至93分钟晚期扫描时间框架（最佳DTP方案）下达到最高相关性。
证明了使用基于总体的输入函数模型，从注射后早期和晚期3分钟/床位常规静态扫描生成Patlak K [F] FDG图像的可行性，并确定了最佳DTP扫描方案。结果表明，DTP-K与金标准K图像之间的高度相关性显著大于RI与金标准K图像之间的相关性。
