From the Departments of Medical Physics (R.B.), Radiation Oncology (S.S., M.V.V.), and Radiology (M.d.R.P.J.), Complejo Hospitalario Universitario de Albacete (CHUA), C/ Hnos Falcó 37, 02006 Albacete, Spain; Renewable Energy Research Institute, University of Castilla-La Mancha, Albacete, Spain (J.C.V., M.C.G.); and Mansilla Diagnóstico por Imagen, Albacete, Spain (F.M.L.).
Radiology. 2018 Aug;288(2):407-415. doi: 10.1148/radiol.2018172361. Epub 2018 Apr 24.
Purpose To identify the reproducible and nonredundant radiomics features (RFs) for computed tomography (CT). Materials and Methods Two phantoms were used to test RF reproducibility by using test-retest analysis, by changing the CT acquisition parameters (hereafter, intra-CT analysis), and by comparing five different scanners with the same CT parameters (hereafter, inter-CT analysis). Reproducible RFs were selected by using the concordance correlation coefficient (as a measure of the agreement between variables) and the coefficient of variation (defined as the ratio of the standard deviation to the mean). Redundant features were grouped by using hierarchical cluster analysis. Results A total of 177 RFs including intensity, shape, and texture features were evaluated. The test-retest analysis showed that 91% (161 of 177) of the RFs were reproducible according to concordance correlation coefficient. Reproducibility of intra-CT RFs, based on coefficient of variation, ranged from 89.3% (151 of 177) to 43.1% (76 of 177) where the pitch factor and the reconstruction kernel were modified, respectively. Reproducibility of inter-CT RFs, based on coefficient of variation, also showed large material differences, from 85.3% (151 of 177; wood) to only 15.8% (28 of 177; polyurethane). Ten clusters were identified after the hierarchical cluster analysis and one RF per cluster was chosen as representative. Conclusion Many RFs were redundant and nonreproducible. If all the CT parameters are fixed except field of view, tube voltage, and milliamperage, then the information provided by the analyzed RFs can be summarized in only 10 RFs (each representing a cluster) because of redundancy.
确定可重现且非冗余的 CT 影像组学特征（RFs）。
使用测试-重测分析、改变 CT 采集参数（以下简称内 CT 分析）和比较具有相同 CT 参数的五台不同扫描仪（以下简称间 CT 分析），对两个体模进行 RF 重现性测试。通过一致性相关系数（作为变量之间一致性的度量）和变异系数（定义为标准差与平均值的比值）选择可重现的 RF。通过层次聚类分析对冗余特征进行分组。
共评估了 177 个包括强度、形状和纹理特征的 RF。测试-重测分析显示，根据一致性相关系数，91%（177 个中的 161 个）的 RF 具有可重现性。基于变异系数的内 CT RF 的可重复性，从修改螺距因子时的 89.3%（177 个中的 151 个）到修改重建核时的 43.1%（177 个中的 76 个）不等。基于变异系数的间 CT RF 的可重复性也显示出较大的材料差异，从 85.3%（177 个中的 151 个；木材）到仅 15.8%（177 个中的 28 个；聚氨酯）不等。层次聚类分析后确定了 10 个聚类，每个聚类选择一个 RF 作为代表。
许多 RF 是冗余且不可重现的。如果除了视野、管电压和毫安数外，所有 CT 参数都固定，则由于冗余，分析的 RFs 提供的信息可以仅用 10 个 RF （每个代表一个聚类）来概括。
