Image Feature	Description
Size
Volume (mm3)	Volume of lesion
Effective greatest dimension (mm)	Greatest dimension of a sphere with the same volume as the lesion
Surface area(mm2)	Lesion surface area
Maximum linear size(mm)	Maximum distance between any two voxels in the lesion
Shape
Sphericity	Similarity of the lesion shape to a sphere
Irregularity	Deviation of the lesion surface from the surface of a sphere
Surface area-to-volume ratio(1/mm)	Ratio of surface area to volume
Morphology
Margin sharpness	Mean of the image gradient at the lesion margin
Variance of margin sharpness	Variance of the image gradient at the lesion margin
Variance of radial gradient histogram	Degree to which the enhancement structure extends in a radial pattern originating from the center of the lesion
Enhancement texture
Angular second moment(energy)	Image homogeneity
Contrast	Location image variations
Correlation	Image linearity
Entropy	Randomness of the gray levels
Sum of squares(variance)	Spread in the gray-level distribution
Difference entropy	Randomness of the difference of neighboring voxels’ gray levels
Difference variance	Variations of difference of gray levels between voxel pairs
Inverse difference moment	Image homogeneity
Sum average	Overall brightness
Sum entropy	Randomness of the sum of gray levels of neighboring voxels
Sum variance	Spread in the sum of the gray levels of voxel-pair distribution
Information measure of correlation 1	Nonlinear gray-level dependence
Information measure of correlation 2	Nonlinear gray-level dependence
Maximum correlation coefficient	Nonlinear gray-level dependence
Kinetic curve assessment
Maximum enhancement	Maximum contrast enhancement
Time to peak(s)	Time at which the maximum enhancement occurs
Uptake rate(1/s)	Uptake speed of the contrast enhancement
Washout rate(1/s)	Washout speed of the contrast enhancement
Curve-shape index	Difference between late and early enhancements
Enhancement at first postcontrast time point	Enhancement at first postcontrast time point
Signal-to-enhancement ratio	Ratio of the initial enhancement to the overall enhancement
Volume of most enhancing voxels(mm3)	Volume of the most enhancing voxels
Total rate variation(1/s2)	How rapidly the contrast will enter and exit from the lesion
Normalized total rate variation(1/s2)	How rapidly the contrast will enter and exit from the lesion
Enhancement-variance kinetics
Maximum variance of enhancement	Maximum spatial variance of contrast enhancement over time
Time to peak at maximum variance(s)	Time at which the maximum variance occurs
Enhancement-variance increasing rate(1/s)	Rate of increase of the enhancement variance during uptake
Enhancement-variance decreasing rate(1/s)	Rate of decrease of the enhancement variance during washout