An improved region-growing motion tracking method using more prior information for 3D ultrasound elastography

Document Type


Publication Date



Department of Biomedical Engineering


Three-dimensional (3D) ultrasound elastography can provide 3D tissue stiffness information that may be used during clinical diagnoses. In the framework of strain elastography, motion tracking plays an important role. In this study, an improved 3D region-growing motion tracking (RGMT) algorithm based on a concept of exterior boundary points was developed. In principle, the proposed method first determines displacement at some seed points by strictly checking the local correlation and continuity in the neighborhood of those seeds. Subsequent displacement estimation is then conducted from these initial seeds to obtain displacements associated with other locations. This RGMT algorithm is designed to use more known information -including displacements and correlation values of all known-displacement neighboring points -to estimate the displacement of an unknown-displacement point, whereas previous RGMT methods employed information from only one such point. The algorithm was tested on 3D ultrasound volumetric data acquired from a simulation, a tissue-mimicking phantom and 5 human subjects. Motion compensated cross-correlations (MCCC), strain contrast, and displacement Laplacian values (representing smoothness of an estimated displacement field) were calculated and used to evaluate merits of the proposed RGMT method. Compared to a previously published RGMT method, results show that the proposed RGMT method can provide smaller displacement errors, smoother displacements and improve strain contrast while maintaining reasonably high MCCC values, indicating good motion tracking quality. The proposed method is also computationally more efficient. In summary, our preliminary results demonstrated that the proposed RGMT algorithm is capable of obtaining high-quality 3D strain elastographic data using modified clinical equipment.

Publication Title

IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control