Table 3.

Radiomics feature naming convention

Class	Abbreviation	Description
Modality	PET	Positron emission tomography
	CT	Computed tomography
Image Filter	Original	No filter applied
	Wavelet-HLH	Wavelet filtering
	Square	Takes the square of the image
	Gradient	gradient magnitude
	lbp-2D	Calculates and returns a local binary pattern applied in 2D
Matrix	firstorder	Voxel intensities within the image ROI through commonly used and basic metrics
	glcm	Gray-level co-occurrence matrix
	glrlm	Gray-level run length matrix
	glszm	Gray-level size zone
Index	Kurtosis	Kurtosis is a measure of the ‘peakedness’ of the distribution of values in the image ROI
	Median	The median gray-level intensity within the ROI
	Skewness	Skewness measures the asymmetry of the distribution of values about the mean value
	Idmn	IDMN (inverse difference moment normalized) is a measure of the local homogeneity of an image
	ClusterShade	Cluster shade is a measure of the skewness and uniformity of the GLCM
	Imc1	IMC1 assesses the correlation between the probability distributions of i and j in the GLCM
	HighGrayLevelRunEmphasis	HighGrayLevelRunEmphasis measures the distribution of the higher gray-level values in the GLRLM
	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
	LowGrayLevelZoneEmphasis	LGLZE measures the distribution of lower gray-level size zones, with a higher value indicating a greater proportion of lower gray-level values and size zones in the image
	SizeZoneNonUniformity	SZN measures the variability of size zone volumes in the image, with a lower value indicating more homogeneity in size zone volumes