The instability of atherosclerotic coronary plaques is related to their histological composition and the thickness of their fibrous caps. Therefore, recognition of the tissue characteristics of coronary plaques is important to understand and prevent coronary artery disease. Recently, an ultrasound integrated backscatter (IB) technique has been developed. Ultrasound signals have unique characteristics of reflection. That is, the ultrasound IB power ratio is a function of the difference in acoustic characteristic impedance between the medium and target tissue, and the acoustic characteristic impedance is determined by the density of tissue multiplied by the speed of sound. This principle allows for tissue characterization of coronary plaques for the risk stratification in patients with coronary artery disease. Two- and three-dimensional IB color-coded maps for the evaluation of tissue components can be constructed to detect four major components: fibrous, dense fibrosis, lipid pool, and calcification. Many studies have shown the reliability and usefulness of the IB technique.