Research Of Ultrasound Elastography In Human Tissues

Ultrosound elastography is a new mode of imaging that produces tissue elasticity. It could provide important reference value for disease diagnosis. In recent years, Ultrosound elastography has been a hot toptic in the research field of medical image processing. The compression is a key factor of influencing elastography. At present, the instrument of elastography allows lower compression and limits detecting depth in the clinical application.This paper introduced the study state of ultrasound elastography at home and abroad and the basic principle of elastography in tissue. In this paper, elastography methods were studied based on the changes of compression.In this paper, strain profiles of soft tissue under different compression were calculated based on the finite element analysis method. The results of finite element analysis could provide important reference value for work in the future. To obain pre-compression and post- compression rf data, Field 2 ultrasound simulator was introduced. Using Field 2 ultrasound simulator and results of finite element analysis, synthetic pre-compression and post-compression rf data were generated. In the future, the simulation data were used to validate algorithm.Different ways to estimate the field displacement allowed tissue to be compressed under different compression. Tissue sideslip was very limited during less on 2% tissue compression, so one-dimensional upsampled cross correlation with three different Interpolation methods were used to estimate the displacement field and strain field. Also, the results of three different Interpolation methods were compared. However, this method can?t overcome the problem of tissue sideslip during more on 2% tissue compression. Therefore, the extended combined autocorrelation was studied. when tissue compression was less on 5%, this method can estimate the accurate displacement and strain through a tissue-mimicking phantom testing.In order to fit bigger compression, this paper produced an ultrasound elastography method based on B mode ultrasound images. The method combined rigid and nonrigid registration based on B-spline was used to estimate the displacementèeld from the pre and post-compression B mode ultrasound images. The displacement captured the global and local motion of the B mode images. Through experimental data testing, the method can correctly obtain the strain information when tissue compression was 8%, and shows the potential clinical value.