| Biological soft tissue elasticity imaging using ultrasound is studied in this paper. Ordinary ultrasonic imaging using acoustic impedance as the imaging parameters can only reflect the change and the distribution of acoustic properties. When the lesion acoustic impedance changes very little while the elasticity varies much, it is necessary to detect the change in the mechanical properties of tissue using ultrasound elasticity imaging. Elasticity imaging gradually becomes the focus of ultrasound imaging in medical field.The methods to realize ultrasonic elasticity imaging mainly include the traditional elasticity imaging, radiation force imaging and shear wave imaging. The traditional elasticity imaging is a static compression method based on elasticity and strain estimation. Radiation force imaging and shear wave imaging are based on acoustic radiation force.In this paper, the principle and development of ultrasound elasticity imaging are reviewed, and the simulation on ultrasound elasticity imaging of soft tissue by using finite element method was studied. The simulation results show that the use of micro-strain compression method can be realized from the distribution of elastic tissue imaging. Besides, the tissue model is revised by adding consideration of biological tissue viscoelasticity. The simulation results using this optimization model show that the stress, strain and displacement in the tissue are functions of time, which coincide well with the real situation. |
