Table E2.
Description of Radiomic Features
| Radiomic feature | Description |
|---|---|
| original_shape_MajorAxisLength | This feature yields the largest axis length of the ROI-enclosing ellipsoid and is calculated using the largest principal component λmajor. The principal component analysis is performed using the physical coordinates of the voxel centers defining the ROI. It, therefore, takes spacing into account but does not make use of the shape mesh. |
| original_firstorder_Kurtosis | Kurtosis is a measure of the “peakedness” of the distribution of values in the image ROI. A higher kurtosis implies that the mass of the distribution is concentrated toward the tail(s) rather than toward the mean. A lower kurtosis implies the reverse: the mass of the distribution is concentrated toward a spike near the mean value. |
| original_ngtdm_Busyness | A measure of the change from a pixel to its neighbor. A high value for busyness indicates a “busy” image, with rapid changes in intensity between pixels and its neighborhood. |
| original_glszm_GrayLevelNonUniformity | Measures the similarity of gray-level intensity values in the image, where a lower GLN value correlates with a greater similarity in intensity values. |
| original_glcm_Correlation | Correlation is a value between 0 (uncorrelated) and 1 (perfectly correlated) showing the linear dependency of gray-level values to their respective voxels in the GLCM. |
| original_glsz m_Zon eVariance | ZV measures the variance in size volumes for the zones. |
| original_ngtdm_Contrast | Contrast is a measure of the spatial intensity change but is also dependent on the overall gray-level dynamic range. Contrast is high when both the dynamic range and spatial change rate are high, that is, an image with a large range of gray levels, with large changes between voxels and their neighborhood. |
| original_shape_Sphericity | Sphericity is a measure of the roundness of the shape of the tumor region relative to a sphere. It is a dimensionless measure, independent of scale and orientation. The value range is 0<sphericity≤1, where a value of 1 indicates a perfect sphere (a sphere has the smallest possible surface area for a given volume, compared with other solids). |
| original_gldm_DependenceVariance | Measures the variance in dependence size in the image. |
GLCM = grey level co-occurrence matrix; GLN = gray level non-uniformity; ROI = region of interest; ZV = zone variance.