A comparison of the motion tracking of 2-D ultrasonic B-mode tissue images with a calibrated phantom

In evaluating tissue motion, it is necessary to know the precision and relative error associated with correlation tracking as a function of distance. Quantitative estimates of tissue compressibility, elasticity, lesion mobility and other mechanical properties of tissue are largely based on tissue displacements and in the accuracy and precision of its estimation. To quantify the uncertainty of speckle tracking, the motion of a tissue phantom was tracked and compared with known displacements. For planar translations, a relative tracking error ranging from 14% to 18% was found for tissue displacements ranging from 2.0 mm and 14.1 mm. Simulated tracking was performed for six translational and rotational motions. These results suggest that computational estimates of tissue velocity, compressibility, elasticity and mobility should be based on an overall uncertainty of ±18% relative to known tissue displacements between 2.0 mm and 14.1 mm.