Evaluation of the Effect of Strain-Hardening Characteristic of Soft Tissues on Breast-Elastograms

Elastography is an ultrasonic imaging technique that produces images of the Young's modulusdistribution of compliant tissue. This distribution is derived from ultrasonically estimated longitudinalinternal strains induced by an external compression of the tissue. The practice of this technique is generallyaccomplished under the assumption of a linear stress-strain relationship in biological tissue. Thisassumption is not valid for most biological tissues even for small applied compressions. However, theapplication of larger compressions to increase the strain contrast has a growing trend. The nonlinear stressstrainrelationship, or in a more precise statement the strain-hardening characteristic of different breasttissue types significantly changes the contrast in breast elastograms, esp. for large applied compressions.The elastic moduli of normal fibrous and glandular breast tissue along with cancerous lesions are straindependent,in a manner that the tissues’ stiffness increase with applied compression in different ratios. Inthis paper, we represent a model for the alterations of Young’s moduli of normal and different pathologicalbreast tissues due to applied force. This model is achieved base on very precise indentation experimentalresults under no assumption for soft tissues characteristics. Thanks to its simplicity, it could be used toevaluate elastogram's quality parameters.

کلیدواژه ها:

Elastography ، Young’s Modulus ، Strain-Hardening ، Breast