A Method of Tissue Elasticity Estimation Based on Three-Dimensional Displacement Vector

Abstract

For assessing the tissue elastic properties based on 3D information of displacement and strain induced by static deformation, we propose an estimator of 3D displacement vectors. This method is composed of the combination of the weighted phase gradient method (WPG), which utilizes the gradient of the plane obtained from the phase shift at each receiving element on the 2D array, and combined autocorrelation method (CA), which is phase domain processing without aliasing. Large displacements required for highly accurate measurements can be measured by this method. In addition, we develop a tissue elasticity reconstruction method using the measured 3D displacement vectors. Computer simulations reveal that our methods are valid for evaluating the elastic structures of tissues based on 3D information.

3D Myocardial Contraction Imaging Based on Dynamic Grid Interpolation: Theory and Simulation Analysis

“…The weighted phase gradient method (14) (15) is one type of spatial compounding methods. The displacement vectors are compounded by phase-shifts which are obtained from a 2-D array transducer.…”

“…Radio frequency (RF) signals for each scan line are received at all elements in the probe. The phase-shifts at every measuring point between two consecutive frames are calculated by the CAM (13) or the ECAM (19) (20) , and then the displacement vectors are calculated by WPGM (14) (15) from obtained phase-shifts. At the same time, the B-mode image, which is generated by the RF signals obtained from the aperture in the center transducer, is acquired.…”

“…Hence, it is not convenient and the processing speed is not fast. In order to solve the above problems, a myocardial strain imaging system based on the combined autocorrelation method (CAM) (13) and the 3-D weighted phase gradient method (WPGM) (14) (15) , which can detect all directions' true displacement vectors, has been proposed previously (16)- (18) . In this research, in order to obtain a more accurate phase-shift, a new method which incorporates an extended combined autocorrelation method (ECAM) (19) (20) into the WPGM is proposed.…”

Ultrasound elastography: Development of novel technologies and standardization

“…Thus far, imaging methods entailing the calculation of a more quantitative elastic modulus based on strain distribution are being investigated. [23][24][25][26] An example is a method of estimating the elastic modulus of a lesion on the basis of the strain ratio using a coupler with a known elastic modulus. 27) As stated above, strain images show the relative difference in elasticity between a lesion such as a mass and the surrounding tissue.…”

A visualization of nonlinear elasticity property of tissues by ultrasound

“…Hence, reconstruction of Young's modulus can be carried out rather simply. The authors have previously used such a linear assumption and have proposed a method for reconstructing the Young's modulus distribution using only the data obtained by measurement of the three-dimensional strain field generated in the tissue by means of a two-dimensional array probe for accurate reconstruction of Young's modulus [1][2][3].…”