超声弹性成象组织运动相关估计与解相关性

生物的软组织弹性成象需要检测组织在应力作用下的应变，跟踪超声图象中运动目标产生的散斑模式可以估计组织运动．文中建立了表征超声散斑运动和组织运动关系的超声散射模型．研究表明，当组织运动幅度较小时，可以用超声散斑图象相关估计方法，获得组织内平移、旋转和不可压缩形的运动分布；组织平移运动超声散斑没有解相关性，旋转运动的解相关性大于形变运动的解相关性；采用较低的换能器频率和较高的波束分辨力可减小散斑的解相关性．

The Correlaton Estimation and Decorrelation of Tissue Motion in Ultrasonic Elasticity Imaging

Soft tissue elasticity imaging requires detecting tissue strain under stress. Tracking the speckle patterns in ultrasonic image produced by moving targets has been shown effective for tissue motion. In this paper, an echographic image formation model is developed to evaluate the relationship of ultrasonic speckle motion and the underlying tissue motion. When small motion amplitudes are involved, the distribution of tissue translation, rotation and incompressible deformation can be obtained by the cross correlation of ultrasonic speckle patterns. In the linear scan case, translation generates identical speckle translation. However, the decorrelation of rotation is greater than that of incompressible deformation. The lower the transducer frequency is and the smaller the size of beam is, the higher cross correlation of speckle is.