Table 2.

Selected features with descriptions

Feature category		Features of early recurrence vs. non-early recurrence
Texture features	GLCM	X45.7DifferenceEntropy
		X135.7Dissimilarity
		X0.1InformationMeasureCorr1
		X90.7InformationMeasureCorr2
		X45.7InverseVariance
	GLRCM	X90HighGrayLevelRunEmpha
Shape features		Compactness1
		Mass
		Orientation
		Roundness
Intensity histogram features	Intensity Histogram	Kurtosis
Notes: GLCM, Gray-level co-occurrence matrix; and GLRLM, Gray-level run-length matrix. GLCM features have been constructed by four directions (θ = 0°, 45°, 90°, and 135°) and three offsets (d = 1, 4, 7); and GLRLM features have been constructed by two directions (θ = 0°, 90°) and one offset (d = 1).