Evaluation of internal and shell stiffness in the differential diagnosis of breast non-mass lesions by shear wave elastography

Table 1 Comparison of general information between the benign group and the malignant non-mass lesions group

Group	Age (yr)	Maximum diameter (cm)	Location		Amenorrhea		Lactation history
			Left	Right	Yes	No	Yes	No
Benign (n = 66)	49.70 ± 10.38	2.10 ± 1.52	38	28	17	49	55	11
Malignant (n = 52)	50.56 ± 9.27	2.38 ± 1.64	27	25	13	39	44	8
t/χ2 value	-0.205	-0.959	0.376		0.009		0.035
P value	0.419	0.339	0.540		0.925		0.851

Table 2 Comparison of internal elasticity parameters of non-mass lesions (kPa)

Internal parameter	Benign (n = 66)	Malignant (n = 52)	t value	P value
Emax	42.43 ± 20.62	97.95 ± 23.56	-13.634	0.000
Emean	18.34 ± 7.16	32.62 ± 14.98	-6.823	0.000
Emin	4.26 ± 2.05	5.00 ± 2.47	-1.778	0.078
Esd	6.34 ± 3.48	15.39 ± 4.17	-12.848	0.000

Emax: Maximum; Emean: Mean; Min: Minimum; Esd: Elastic values and the standard deviation.

Table 3 Comparison of elasticity parameters around non-mass lesions

Peripheral parameter		Benign (n = 66)	Malignant (n = 52)	t/χ2 value	P value
“Stiff rim” sign		6	26	24.628	0.000
Shell at 1 mm	E1 max	45.53 ± 22.81	125.41 ± 35.68	-14.765	0.000
	E1 mean	24.94 ± 7.92	45.49 ± 17.71	-8.425	0.000
Shell at 1.5 mm	E1.5 max	46.61 ± 22.39	136.40 ± 38.39	-15.889	0.000
	E1.5 mean	25.36 ± 8.52	49.64 ± 18.98	-9.281	0.000
Shell at 2 mm	E2 max	50.43 ± 24.62	153.95 ± 35.56	-18.655	0.000
	E2 mean	26.34 ± 7.16	54.62 ± 17.98	-11.668	0.000
Shell at 2.5 mm	E2.5 max	48.43 ± 25.62	167.95 ± 37.56	-20.506	0.000
	E2.5 mean	29.34 ± 7.16	69.62 ± 19.98	-15.200	0.000
Shell at 3 mm	E3 max	42.43 ± 20.62	153.95 ± 23.56	-27.386	0.000
	E3 mean	26.34 ± 7.16	58.62 ± 14.98	-15.424	0.000

Table 4 Sensitivity, specificity, accuracy, cutoff value and the area under the curve of each parameter

Parameter	Sensitivity (%)	Specificity (%)	Accuracy (%)	Cutoff value	AUC
“Stiff rim” sign	50.00	90.91	72.88	-	-
Emax	74.33	66.80	67.05	67.61	0.707
Emean	54.95	68.47	59.86	28.05	0.626
Emin	36.15	49.60	43.64	4.96	0.425
Esd	70.18	63.67	68.93	11.30	0.687
E1 max	83.61	75.01	75.04	84.65	0.795
E1 mean	68.29	57.94	63.69	33.08	0.647
E1.5 max	83.00	74.18	77.00	95.60	0.789
E1.5 mean	74.48	63.95	65.24	36.24	0.692
E2 max	86.36	76.04	80.06	100.50	0.826
E2 mean	75.53	66.11	68.51	33.97	0.704
E2.5 max	94.57	85.86	87.44	94.62	0.900
E2.5 mean	79.05	70.04	80.51	36.17	0.746
E3 max	90.52	81.83	84.03	88.56	0.881
E3 mean	76.82	68.11	76.86	35.48	0.734

AUC: The areas under the curve; Emax: Maximum; Emean: Mean; Min: Minimum; Esd: Elastic values and the standard deviation.