Figure 1.

Basis of contrast harmonic imaging. When irradiated with an ultrasound beam, the microbubbles in the contrast medium vibrate. Many harmonic signals are emitted. At this time, when the transmitted ultrasound is received transmitted ultrasound is received, both the tissue and the microbubbles generates harmonic components from the microbubbles. Harmonic components from microbubbles are at higher levels than harmonic components from tissue. The harmonic components from the microbubbles are at a higher level than the harmonic components from the tissue. By selectively delineating the second harmonic component, the signal from the microbubbles is visualized more strongly than the signal from the tissue.