IEEE Trans Med Imaging. 2022 Dec;41(12):3824-3834. doi: 10.1109/TMI.2022.3197363. Epub 2022 Dec 2.
Tumor perfusion and vascular properties are important determinants of cancer response to therapy and thus various approaches for imaging perfusion are being explored. In particular, Intravoxel Incoherent Motion (IVIM) MRI has been actively researched as an alternative to Dynamic-Contrast-Enhanced (DCE) CT and DCE-MRI as it offers non-ionizing, non-contrast-based perfusion imaging. However, for repetitive treatment assessment in a short time period, high cost, limited access, and inability to scan at the bedside remain disadvantages of IVIM MRI. We propose an analysis framework that may enable 3D DCE Ultrasound (DCE-US) - low cost, bedside imaging with excellent safety record - as an alternative modality to IVIM MRI for the generation of DCE-US based pseudo-diffusivity maps in acoustically accessible anatomy and tumors. Modelling intravascular contrast propagation as a convective-diffusive process, we reconstruct parametric maps of pseudo-diffusivity by solving a large-scale fully coupled inverse problem without any assumptions regarding local constancy of the reconstructed parameters. In a mouse tumor model, we demonstrate that the 3D DCE-US pseudo-diffusivity is repeatable, sensitive to treatment with an antiangiogenic agent, and moderately correlated to histological measures of perfusion and angiogenesis.
肿瘤灌注和血管特性是癌症对治疗反应的重要决定因素，因此正在探索各种用于成像灌注的方法。特别是，体素内不相干运动（IVIM）MRI 作为动态对比增强（DCE）CT 和 DCE-MRI 的替代方法得到了积极研究，因为它提供了非电离、非对比的灌注成像。然而，对于在短时间内进行重复治疗评估，IVIM MRI 仍然存在高成本、有限的获取途径以及无法在床边进行扫描的缺点。我们提出了一种分析框架，该框架可能使 3D 动态对比增强超声（DCE-US）成为替代 IVIM MRI 的选择，DCE-US 是一种低成本、床边成像，具有出色的安全性记录，可用于在可听解剖结构和肿瘤中生成基于 DCE-US 的假性扩散图。通过将血管内对比传播建模为对流-扩散过程，我们通过求解没有关于重建参数局部恒定性的假设的大规模完全耦合反问题来重建假性扩散的参数图。在小鼠肿瘤模型中，我们证明 3D DCE-US 的假性扩散具有可重复性，对血管生成抑制剂的治疗敏感，并且与灌注和血管生成的组织学测量中度相关。
