Table 3. Logistic regression analysis of variables independently associated with false positive or negative results of E_ratio.

Eratio	Variable	Odds ratio (95% CI)	P value
False positive	Palpability	3.167 (1.679, 5.975)	0.0004
	Lesion size (mm)	1.025 (0.993, 1.059)	0.127
	Distance from skin (mm)	1.028 (0.918, 1.150)	0.633
	Lesion E mean (kPa)	1.059 (1.044, 1.075)	<0.0001
	Lesion E max (kPa)	1.045 (1.033, 1.057)	<0.0001
	Fat E mean (kPa)	0.849 (0.813, 0.886)	<0.0001
	Fat E max (kPa)	0.857 (0.827, 0.889)	<0.0001
False negative	Palpability	0.360 (0.145, 0.889)	0.027
	Lesion size (mm)	0.946 (0.904, 1.091)	0.059
	Distance from skin (mm)	0.876 (0.734, 1.045)	0.141
	Lesion E mean (kPa)	0.967 (0.958, 0.975)	<0.0001
	Lesion E max (kPa)	0.972 (0.965, 0.979)	<0.0001
	Fat E mean (kPa)	1.134 (1.097, 1.173)	<0.0001
	Fat E max (kPa)	1.091 (1.063, 1.120)	<0.0001

E_ratio = elasticity ratio, the ratio between the mean elasticity values in the lesion and in the fatty tissue, CI = Confidence interval, E_mean = mean elasticity value, E_max = maximum elasticity value, Distance from skin = vertical distance from skin to ROI for the fat