The development of novel, clinically applicable ultrasound imaging techniques is the primary goal of our laboratory's research. We are particularly interested in the use of motion-tracking techniques to enhance the contrast of ultrasound images. Motion of tissues, both physiological and artificial, can reveal the differences in tissue stiffness and type, as well as the presence of implanted devices. Furthermore, detection and tracking of tissue motion can guide the delivery of therapeutic agents. The interaction of ultrasound with tissue, statistical properties of ultrasound echoes and signal processing techniques are the topics we study in order to achieve these goals.