Institute for Experimental Molecular Imaging, RWTH Aachen University Clinic and Helmholtz Institute for Biomedical Engineering, Pauwelsstr. 30, 52074 Aachen, Germany.
Department of Medical Engineering, Ruhr-University Bochum, Universitätsstr. 150, 44801 Bochum, Germany.
Contrast Media Mol Imaging. 2017 May 30;2017:2098324. doi: 10.1155/2017/2098324. eCollection 2017.
The purpose of this study was the automated generation and validation of parametric blood flow velocity maps, based on contrast-enhanced ultrasound (CEUS) scans.
Ethical approval for animal experiments was obtained. CEUS destruction-replenishment sequences were recorded in phantoms and three different tumor xenograft mouse models. Systematic pixel binning and intensity averaging was performed to generate parameter maps of blood flow velocities with different pixel resolution. The 95% confidence interval of the mean velocity, calculated on the basis of the whole tumor segmentation, served as ground truth for the different parameter maps.
In flow phantoms the measured mean velocity values were only weakly influenced by the pixel resolution and correlated with real velocities ( ≥ 0.94, < 0.01). In tumor xenografts, however, calculated mean velocities varied significantly ( < 0.0001), depending on the parameter maps' resolution. Pixel binning was required for all in vivo measurements to obtain reliable parameter maps and its degree depended on the tumor model.
Systematic pixel binning allows the automated identification of optimal pixel resolutions for parametric maps, supporting textural analysis of CEUS data. This approach is independent from the ultrasound setup and can be implemented in the software of other (clinical) ultrasound devices.
本研究旨在基于对比增强超声（CEUS）扫描，自动生成和验证血流速度参数图。
本动物实验获得了伦理批准。在体模和三种不同的肿瘤异种移植小鼠模型中记录了 CEUS 破坏-再灌注序列。通过系统的像素分组和强度平均，生成了具有不同像素分辨率的血流速度参数图。基于整个肿瘤分割计算的平均速度的 95%置信区间作为不同参数图的真实值。
在血流体模中，测量的平均速度值仅受到像素分辨率的微弱影响，与真实速度高度相关（≥0.94，<0.01）。然而，在肿瘤异种移植中，计算出的平均速度值差异显著（<0.0001），取决于参数图的分辨率。所有体内测量都需要进行像素分组以获得可靠的参数图，其程度取决于肿瘤模型。
系统的像素分组允许自动确定参数图的最佳像素分辨率，支持 CEUS 数据的纹理分析。这种方法独立于超声设置，可以在其他（临床）超声设备的软件中实现。
