IEEE Trans Med Imaging. 2014 Jun;33(6):1390-400. doi: 10.1109/TMI.2014.2312254.
Quantitative ultrasound (QUS) spectroscopic techniques in conjunction with maximum mean discrepancy (MMD) have been proposed to detect, and to classify noninvasively the levels of cell death in response to cancer therapy administration in tumor models. Evaluation of xenograft tumor responses to cancer treatments were carried out using conventional-frequency ultrasound at different times after chemotherapy exposure. Ultrasound data were analyzed using spectroscopic techniques and multi-parametric QUS spectral maps were generated. MMD was applied as a distance criterion, measuring alterations in each tumor in response to chemotherapy, and the extent of cell death was classified into less/more than 20% and 40% categories. Statistically significant differences were observed between "pre-" and "post-treatment" groups at different times after chemotherapy exposure, suggesting a high capability of proposed framework for detecting tumor response noninvasively. Promising results were also obtained for categorizing the extent of cell death response in each tumor using the proposed framework, with gold standard histological quantification of cell death as ground truth. The best classification results were obtained using MMD when applied on histograms of QUS parametric maps. In this case, classification accuracies of 84.7% and 88.2% were achieved for categorizing extent of tumor cell death into less/more than 20% and 40%, respectively.
定量超声（QUS）光谱技术结合最大均值差异（MMD）已被提出用于检测，并对肿瘤模型中对癌症治疗的细胞死亡水平进行无创分类。在化疗暴露后的不同时间点，使用常规频率超声评估异种移植肿瘤对癌症治疗的反应。使用光谱技术分析超声数据，并生成多参数 QUS 光谱图。MMD 作为距离标准，用于测量每个肿瘤对化疗的反应变化，将细胞死亡程度分为小于/大于 20%和 40%两类。在化疗暴露后的不同时间点，“预处理”和“后处理”组之间观察到统计学上的显著差异，这表明所提出的框架具有很高的能力，可以无创地检测肿瘤反应。使用所提出的框架对每个肿瘤的细胞死亡程度进行分类也获得了有希望的结果，将细胞死亡的金标准组织学量化作为基准。当将 MMD 应用于 QUS 参数图的直方图时，获得了最佳的分类结果。在这种情况下，将肿瘤细胞死亡程度分为小于/大于 20%和 40%的分类准确率分别达到 84.7%和 88.2%。
