Table 2

Selected radiomic features and their weights

FilterContentFeatureWeight
Wavelet-LLHNGTDMContrastc
Wavelet-LHLGLCMMCC−0.017279351
Wavelet-LHHGLCMCluster shade0.092164975
Wavelet-LHHGLCMCorrelation0.006937257
Wavelet-HLLFirst OrderSkewness−0.045636121
Wavelet-HLLGLCMJoint energy−0.000468081
Wavelet-HLLGLCMMCC−0.003898945
Wavelet-HLLNGTDMStrength−0.093386704
Wavelet-HLHGLCMImc1−0.098968757
Wavelet-HLHGLCMMaximum probability0.011684371
Wavelet-HLHGLRLMRun entropy0.1127218
Wavelet-HHLFirst OrderKurtosis0.078565624
Wavelet-LLLGLCMImc2−0.04851471
Log-sigma-0–5 mm-3DFirst OrderKurtosis−0.061965144
Log-sigma-1–0 mm-3DGLCMMCC−0.023173336
Log-sigma-2–0 mm-3DGLSZMLarge area low gray level emphasis−0.167740327
Log-sigma-3–0 mm-3DGLCMImc20.068711955
Log-sigma-4–0 mm-3DGLSZMLarge area high gray level emphasis−0.003414446
Lbp-2DGLSZMSize zone nonuniformity normalized−0.001849751
Square rootGLSZMGray level nonuniformity normalized0.097057736
Square rootNGTDMStrength−0.022030986
LogarithmGLCMImc2−0.062773043
LogarithmGLRLMRun entropy−0.025857206
LogarithmGLRLMRun variance−0.002688257
ExponentialFirst OrderUniformity0.077259714
ExponentialGLDMDependence nonuniformity normalized0.058133675
ExponentialGLDMLarge dependence high gray level emphasis−0.051759668
GradientGLDMSmall dependence low gray level emphasis−0.030119555

  • First order, such as the mean, maximum, minimum, and so on.

  • ‘L’ means a low-pass filter.

  • ‘H’ means a high-pass filter.

  • ‘HLH’, respectively, means x, y. and z axis of the wavelet filter.

  • ‘Wavelet-HLH’ means that a high-pass filter, a low-pass filter and a high-pass filter was applied on x, y, and z axis of the wavelet filter, which was named analogously for ‘Wavelet-HHH’ and ‘Wavelet-LLL’.

  • GLCM, gray level co-occurrence matrix; GLDM, gray level dependence matrix; GLRLM, gray level run length matrix; GLSZM, gray level size zone matrix; MCC, maximal correlation coefficient; NGTDM, neighboring gray tone difference matrix.