AI 中文总结
本研究通过开发有限差分求解器模拟1mm³组织内[18F]FDG的转运与代谢，揭示其分布的亚毫米异质性，统一二室和三室组织室模型并确定适用范围，提升了动态[18F]FDG-PET成像的可解释性。
AI 中文摘要
18F-氟代脱氧葡萄糖([18F]FDG)正电子发射断层扫描(PET)结合室建模是评估细胞代谢的强大非侵入性成像方法。然而，经典的二室和三室组织室模型假设组织内[18F]FDG分布均匀，这一假设需要验证，且这些模型中速率常数的定义和解释并不总是一致。为解决这些问题，我们开发了有限差分求解器，用于模拟1 mm³组织体积内的[18F]FDG转运与代谢，该体积代表PET可分辨的最小体积。我们的模拟揭示了[18F]FDG分布的亚毫米异质性，并表明测得的PET信号不仅取决于细胞代谢活性，还取决于间质[18F]FDG扩散率、血管通透性和血管结构。我们进一步证明，当间质[18F]FDG浓度均匀时，我们的有限差分模拟可简化为三室组织室模型；此外，当血管通透性足够高时，该简化模型本身可简化为二室组织室模型。本研究定量关联了血管通透性、血管结构、细胞摄取动力学、[18F]FDG扩散率和采集时间，还统一了二室和三室组织室模型并确定了它们的适用范围。这些发现加深了我们对[18F]FDG转运动力学的理解，提高了动态[18F]FDG-PET成像的可解释性。
英文摘要
18F-fluorodeoxyglucose ([18F]FDG) positron emission tomography (PET), combined with compartmental modeling, is a powerful non-invasive imaging method for assessing cellular metabolism. However, classical two- and three-tissue compartment models assume homogeneous [18F]FDG distribution within the tissue, which needs justification, and the definition and interpretation of rate constants across these models is not always consistent. To address these issues, we develop a finite difference solver to simulate [18F]FDG transport and metabolism within a 1 mm3 tissue volume, representing the smallest volume resolvable by PET. Our simulations reveal sub-millimeter heterogeneity in [18F]FDG distribution and show that the measured PET signal is dependent not only on cellular metabolic activity but also on interstitial [18F]FDG diffusivity, vascular permeability, and vascular architecture. We further demonstrate that our finite-difference simulation reduces to a three-tissue compartment model when interstitial [18F]FDG concentration is homogeneous. Furthermore, this simplified model itself reduces to the two-tissue compartment model when vascular permeability is sufficiently high. This work quantitatively links vascular permeability, vascular architecture, cellular uptake kinetics, [18F]FDG diffusivity, and acquisition time. It also unifies the two- and three-tissue compartment models and identifies their applicable regimes. These findings deepen our understanding of [18F]FDG transport kinetics and enhance the interpretability of dynamic [18F]FDG-PET imaging.
Journal refZhong, X., & Pratx, G. (2026). A microscopic computational simulation of [18F] FDG transport and metabolism identifies valid regimes for compartmental analysis. Physics in Medicine & Biology, 71(12), 125002
