TABLE 1.

In-vivo results of the elastic properties of breast tissues, reported in literature.

Experiment	Tissue types	Experimental protocol	Results/Conclusions	Authors
In vivo	Adipose and glandular tissues IDC (scirrhous carcinoma)	Elastography vs. Sonography	Healthy	Céspedes et al. (1993)
			Adipose tissue: soft (light) in the elastogram and hypoechoic in the sonogram
			Glandular components: firm (dark) in the elastogram and hypoechoic in the sonogram
			Patient
			Well defined hard (black) area, within the soft (white) fat in the elastogram
	Adipose and glandular tissues	MR elastography	Eglandular = 2.45 ± 0.2 kPa	Lawrence et al. (1998)
			Eadipose = 0.43 ± 0.07 kPa
	Carcinoma	MR elastography	Ecarcinoma = 3.5 kPa	Sinkus et al. (2000)
	Surrounding (benign) tissue		Esurrounding tissue = 0.5–1 kPa
	Malignant lesions: invasive mucinous carcinoma IDC	MR elastography	Ecancer = 3.1 ± 0.7 kPa	Xydeas et al. (2005)
			Efibroadenoma = 1.4 ± 0.5 kPa
	Benign lesions: fibroadenoma fibrocystic changes		Efibrocystic changes = 1.7 ± 0.8 kPa
			Esurrounding tissue = 1.2 ± 0.2 kPa
	Adipose and glandular tissues IDC	non-compressive MR elastography	Healthy	Chen et al. (2013)
			Eadipose = 0.33 kPa
			Eglandular = 0.64 kPa
			Patient
			Eadipose = 0.41 ± 0.1 kPa
			Eglandular = 0.90 ± 0.18 kPa EIDC = 1.42 ± 0.17 kPa
	Healthy women: Adipose Fibroglandular Patient with cancer: Invasive Carcinoma IDC ILC	MR elastography	Healthy: Eadipose = 3.3 ± 1.9 kPa	McKnight et al. (2002)
			Efibroglandular = 7.5 ± 3.6 kPa
			Patient
			Eadipose = 4–16 kPa (mean 8 kPa)
			Etumors = 18–94 kPa (mean 33 kPa)
	Adipose and fibroglandular tissues	MR elastography	Eadipose = 17.1067 ± 3.0283–23.5367 ± 4.0347 kPa	Van Houten et al. (2003)
			Efibroglandular = 24.2871 ± 3.0939–30,2995 ± 3.4 kPa
	Adipose tissue Fibroadenoma IDC	Optical coherence tomographic elastography	Eadipose = 4.17 ± 0.074 kPa	Srivastava et al. (2011)
			Efibroadenoma = 9.03 ± 0.215 kPa EIDC = 16.45 ± 1.103 kPa
	Benign: Fibroadenomas Fibrocystic change Fibroadipose tissue Malignant: IDC ILC	Multi-compression	New estimated non-linear parameter benign = 0.163 ± 0.063	Sayed et al. (2013)
			malignant = 1.642 ± 0.261
			Strain ratio (between soft and stiff tissues) benign = 2.135 ± 0.707
		3D Ultrasound elastography	malignant = 4.21 ± 2.108
			Relative mass volume benign = 0.848 ± 0.237
			malignant = 2.18 ± 0.522
	Normal breast tissues (healthy volunteer)	Ultrasound elastography	viscoelastic behavior, more evident at large deformations	Han et al. (2003)
			E = 1.832 kPa, for the maximum displacement of 20 mm
	Dense and non-dense breast tissues (healthy volunteer)	MR elastography	Edense = 0.92 kPa	Hawley et al. (2017)
			Enon-dense = 0.83 kPa
	Adipose and fibroglandular tissues	Elastography precompression levels	Comparing malignant tissues with normal tissues	Barr and Zhang (2012)
	Fibroadenoma	A) 0–10∖%	A, B, and C: Difference in elasticity
	Fibrocystic changes	B) 10–25∖%	D: the elasticity of both types of tissues was similar
	Fat necrosis	C) 25–40∖%	Comparing benign tissues with normal tissues: only in level A, there were significant differences in elasticity
	Malignancy	D) maior 40∖%	Young modulus (kPa) increases in all tissues as precompression increases