Effect of imaging parameters on the echoes from ultrasonic contrast agents

High-resolution contrast-assisted techniques would facilitate differentiation of tissue and microbubble echoes. The authors have found that for the same transmitted time-averaged intensity, the wideband transmission produces an equal or higher received echo intensity from the contrast agent. Thus a wideband imaging scheme could be as effective as the more traditional narrowband technique. In addition, the transmission of wideband high intensity pulses is shown to produce a consistent time domain echo from the microbubbles. This echo is the same whether the bubbles break or remain intact over several pulses. A change in the phase of the transmitted pulse is shown to leave the polarity of the received signal unchanged under a set of experimental conditions