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Copyright ©The Author(s) 2021.
World J Gastroenterol. Jul 7, 2021; 27(25): 3802-3814
Published online Jul 7, 2021. doi: 10.3748/wjg.v27.i25.3802
Table 1 Commonly-used radiomics feature categories according to “order”
“Order”
Paraphrase
Categories
Description
First-orderBased on an intensity histogram of pixel values, providing no information on neighboring interactions or the spatial distributionMeanAverage intensity of the pixels
SkewnessAsymmetry of histogram
KurtosisMagnitude of pixel distribution
EntropyIrregularity of the structure
Second-orderConsiders the spatial relationship between 2 pixelsGrey level co-occurrence matrix (GLCM)Frequency of specific gray values along a distance or direction
Grey level run Length Matrix (GLRLM)Length of consecutive pixels or voxels with the same grey values in a specific direction
Grey level size zone matrix (GLSZM)Length of consecutive pixels or voxels with the same grey values in all directions
Superior-orderDescribes the neighborhood gray difference matrices and the relationship between 3 or more pixelsNeighboring gray tone difference matrix (NGTDM)Describes the sum and average grey levels of discretized voxels in planes
Gray level dependence matrix (GLDM)Describes the coarseness of overall texture by evaluating the grey levels between a voxel and the neighborhood in 3 dimensions