Table 2 Overview of textural features with definitions subdivided into textural features of 1st and 2nd-order

 Heterogeneity

= presence of edges detected by the use of a Laplacian of Gaussian filter

 Intensity

= texture intensity as the voxel value of the corresponding input image voxel

 Average

= noise independent voxel intensity

 Deviation

= correlates with the local range of input image voxel values

 Skewness

= describes if the current neighbourhood has a centered distribution of grey values

 Entropy of co-occurrence matrix

= entropy of the distribution of two co-occurring neighbour grey values

 Number non-uniformity (NGLDM)

= the sum of squared NGLDM matrix elements divided by the sum of (unsquared) matrix elements

 Entropy of NGLDM

= considers NGLDM matrix entries as random variables with an underlying statistical distribution, an image with a certain kind of regularity

 Entropy of heterogeneity

= the randomness on the presence and distribution of edges

 Entropie (NGLDM)

= considering NGLDM matrix entries as random variables with an underlying statistical distribution, an image with a certain kind of regularity

 Contrast (NGTDM)

= correlation of grey value differences between neighbouring voxels (Difference_{greyValueNeigbors}) with the range of voxels in the whole neighbourhood of the current voxel (Range_neighborhood). The texture value for the current voxel is computed as: textureValue_currentVoxel = Range_neighborhood * Difference_{greyValueNeigbors}