Measurement of elastic property of breast tissue for elasticity imaging

Matsumura, Takeshi; Umemoto, Takuya; Fujihara, Y.; Ueno, Ei; Yamakawa, Makoto; Shiina, Tsuyoshi; Mitake, Tsuyoshi

doi:10.1109/ultsym.2009.5442044

Cited by 16 publications

(44 citation statements)

References 6 publications

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“…The modulus of most healthy soft tissue is below 1 kPa: normal colon tissue has been found to possess a steady state modulus of ~700 Pa and normal breast tissue possess a Young's modulus of also ~700 Pa under low stress tests [49,50]. As the elastic modulus of the stiff agarose exceeds that of most healthy soft tissues, we repeated the experiment but with cylindrical channels molded into soft agarose that are closer to normal tissue stiffness [51].…”

Section: Stiffness Of the Vessel-like Constraint Influences Tumor Embmentioning

confidence: 99%

Growth of tumor emboli within a vessel model reveals dependence on the magnitude of mechanical constraint

Kulwatno

Gearhart

Gong

et al. 2020

Preprint

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ABSTRACTTumor emboli – aggregates of tumor cell within vessels – pose a clinical challenge as they are associated with increased metastasis and tumor recurrence. When growing within a vessel, tumor emboli are subject to a unique mechanical constraint provided by the tubular geometry of the vessel. Current models of tumor emboli use unconstrained multicellular tumor spheroids, which neglect this mechanical interplay. Here, we modelled a lymphatic vessel as a 200 μm-diameter channel in either a stiff or soft, bioinert agarose matrix, and we modelled colon or breast cancer tumor emboli with aggregates of HCT116 or SUM149PT cells, respectively. The stiff vessel model constrained the tumor emboli to the cylindrical geometry, which led to continuous growth of the emboli, in contrast to the growth plateau that unconstrained spheroids exhibit. Emboli morphology in the soft vessel model, however, was dependent on the magnitude of mechanical mismatch between the vessel matrix and the cell aggregates. In general, when the elastic modulus of the vessel was greater than the emboli (Eves / Eemb >1), the emboli were constrained to grow within the vessel geometry, and when the elastic modulus of the vessel was less than the emboli (0 < Eves / Eemb < 1), the emboli bulged into the matrix. Inhibitors of myosin-related force generation decreased the elastic modulus and/or increased the stress relaxation of the tumor cell aggregates, effectively increasing the mechanical mismatch. The increased mechanical mismatch after drug treatment was correlated with increased confinement of tumor emboli growth along the vessel, which may translate to increased tumor burden due to the increased tumor volume within the diffusion distance of nutrients and oxygen.INSIGHT BOXThe growth of tumor emboli—aggregates of tumor cells within vessels—is associated with aggressive cancer progression and metastasis. Models of their growth have not taken into account their biomechanical context, where radial expansion is constrained, but lengthwise expansion is free in the vessel. Here, we modelled the vessel geometry with a cylindrical microchannel in a hydrogel. In contrast to unconstrained or fully embedded aggregates, vessel-like constraint promotes growth of emboli in our model. The growth advantage is increased when the matrix is stiffened or actomyosin contractility weakened, both of which effectively increase the magnitude of mechanical constraint. This study sheds light on increased tumor burden in vessel-based growth and indicates a need to study tumor progression in similar environments.

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Section: Stiffness Of the Vessel-like Constraint Influences Tumor Embmentioning

confidence: 99%

Growth of tumor emboli within a vessel model reveals dependence on the magnitude of mechanical constraint

Kulwatno

Gearhart

Gong

et al. 2020

Preprint

View full text Add to dashboard Cite

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“…The test was performed until fracture, at a rate of 1 mm/min. The experimental protocol is based on the studies of Matsumura et al 20 and Umemoto et al 21 These authors took the mechanical assumptions leading to a Young's modulus (E) estimation according to equation (1…”

Section: Experimental Protocolmentioning

confidence: 99%

“…Therefore, a comparison between the mechanical properties of agarose (from the current study) with reference values from breast tissues 20,21 requires similar experimental conditions. Moreover, the strategy followed (mathematical and mechanical considerations) to estimate the Young's modulus must be the same.…”

Section: Introductionmentioning

confidence: 99%

Mechanical characterisation of an organic phantom candidate for breast tissue

Teixeira

Martins

2019

J Biomater Appl

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The aim of this study is to analyse the mechanical properties of agarose, which can be used as a mechanical phantom for breast tissues. In general, tissue mimicking materials may be used to achieve a better understanding of the structure and properties of tissues and organs; this work shares these objectives. The phantom can be used as a tissue surrogate with realistic mechanical behaviour for biomechanical applications. To validate agarose as a suitable mechanical phantom for breast tissues, indentation tests were performed in homogeneous, rectangular agarose blocks. Blocks with different agarose concentrations were moulded and tested. An estimation of the material stiffness was then compared with experimental data on different breast tissues’ types found in literature. The phantom stiffness increased consistently with agarose concentration and stress. The results show that agarose-based mechanical phantoms of stiffer tissues require higher agarose concentrations (0.5% and 0.6%). In contrast, normal tissues can be mimicked with 0.3% and 0.4% of agarose. In addition, it was observed that preconditioning affects the mechanical properties of the gel, as it had already been shown in literature for breast tissues.

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“…A few researchers have measured the elastic modulus of ex vivo human breast tissue and its rate of increase under strain [13][14][15]. The elastic modulus increases more rapidly in cancerous than in benign breast tumor tissues.…”

Section: Noninvasive Breast Cancer Diagnosismentioning

confidence: 99%