Tissue motion assessment from scattered ultrasound echoes

Abstract

Ultrasound has become a standard clinical tool in the diagnosis and treatment of illness and injury. Perhaps the most well‐known use of ultrasound is the noninvasive imaging of different parts of the body. Ultrasound does, however, have other applications in medical diagnoses, such as in tissue characterization and in the measurement of tissue motion in vivo. The measurement of tissue motion is a somewhat broad category. It can include the motion of physically active organs such as the heart and discrete structures such as cardiac valves and arterial walls to diagnose heart disease. It can be used to measure motion in soft tissues (such as the liver) due to the pulsing of an artery in the tissue. The soft tissue motion is a function of elasticity of the tissue, which is directly related to the state of the tissue (diseased or healthy). Finally, the measurement of blood flow velocity is an important parameter in diagnosing coronary diseases such as venous thrombosis. Regardless of the particular application of ultrasound, all applications require the transmission and capture of rf ultrasonic signals. After capture, the signals must be processed in some way to extract the desired information. In the case of estimating tissue motion, many methods exist, ranging from the well‐known and widely implemented Doppler technique to newly developed time domain methods; from estimating velocity from a single rf A‐scan to using multiple M‐mode video images. The topic of this presentation is to review and compare some of the methods currently under development to measure tissue motion from scattered ultrasound echoes. [Work supported by NIH/HL 39704 and NIH/CA 36029.]