Three-Dimensional Tracking Method of Tissue Motion with Biplane Images

Abstract

For real-time three-dimensional tissue motion detection using biplane ultrasound images, we investigated the efficiency of a correlation method in which each region of interest (ROI) is divided into sub-regions so small that the deformation in each subregion can be ignored when estimating its motion in and perpendicular to the image planes. The allowed range of displacement perpendicular to the image planes in sensitively estimating tissue motion by cross-correlation was analyzed. In vitro results with a phantom revealed that the velocity component in the image plane could be detected when the perpendicular displacement between two consecutive frames was as small as 0.4 mm. Moreover it was also revealed that the subregion size must be larger than the speckle size. We also performed in vivo experiments on human liver and found that the tissue motion induced by systole was detectable by our cross-correlation method. The obtained results demonstrated the potential usefulness of the proposed method in medical applications, such as an image guide for minimally invasive therapy.