Quantitative dynamic PET with compartmental modeling has the potential to enable multiparametric imaging and more accurate quantification than static PET imaging. Conventional methods for parametric imaging commonly use a single kinetic model for all image voxels and neglect the heterogeneity of physiologic models, which can work well for single-organ parametric imaging but may significantly compromise total-body parametric imaging on a scanner with a long axial field of view. In this paper, we evaluate the necessity of voxelwise compartmental modeling strategies, including time delay correction (TDC) and model selection, for total-body multiparametric imaging. Methods: Ten subjects (5 patients with metastatic cancer and 5 healthy volunteers) were scanned on a total-body PET/CT system after injection of 370 MBq of ¹⁸F-FDG. Dynamic data were acquired for 60 min. Total-body parametric imaging was performed using 2 approaches. One was the conventional method that uses a single irreversible 2-tissue-compartment model with and without TDC. The second approach selects the best kinetic model from 3 candidate models for individual voxels. The differences between the 2 approaches were evaluated for parametric imaging of microkinetic parameters and the ¹⁸F-FDG net influx rate, K_i. Results: TDC had a nonnegligible effect on kinetic quantification of various organs and lesions. The effect was larger in lesions with a higher blood volume. Parametric imaging of K_i with the standard 2-tissue-compartment model introduced vascular-region artifacts, which were overcome by the voxelwise model selection strategy. Conclusion: The time delay and appropriate kinetic model vary in different organs and lesions. Modeling of the time delay of the blood input function and model selection improved total-body multiparametric imaging.

具有区室建模的定量动态 PET 具有实现多参数成像和比静态 PET 成像更准确的量化的潜力。参数成像的传统方法通常对所有图像体素使用单一动力学模型，而忽略了生理模型的异质性，这对于单器官参数成像效果很好，但可能会严重影响长轴场扫描仪上的全身参数成像的观点。在本文中，我们评估了全身多参数成像的体素分区建模策略的必要性，包括时间延迟校正（TDC）和模型选择。方法： 10 名受试者（5 名转移性癌症患者和 5 名健康志愿者）注射 370 MBq ¹⁸ F-FDG 后，在全身 PET/CT 系统上进行扫描。动态数据采集 60 分钟。使用两种方法进行全身参数成像。一种是传统方法，使用带有或不带有 TDC 的单个不可逆 2 组织室模型。第二种方法从单个体素的 3 个候选模型中选择最佳动力学模型。通过微动力学参数的参数成像和¹⁸ F-FDG 净流入速率K _i评估两种方法之间的差异。结果： TDC对各种器官和病变的动力学定量具有不可忽视的影响。在血容量较高的病变中效果更大。使用标准 2 组织室模型对K _i进行参数化成像会引入血管区域伪影，但通过体素模型选择策略可以克服这一问题。 结论：不同器官和病变的时间延迟和合适的动力学模型有所不同。血液输入函数的时间延迟建模和模型选择改进了全身多参数成像。