(AE) Induced acoustic emission is an effect of ultrasound contrast agents, presenting the interaction between the agent and the incident ultrasound wave.
Microbubbles break down in high-amplitude diagnostic ultrasound energy. The bubble rupture produces a transient pressure wave, which results in a characteristic mosaic pattern from tissues containing the agent. It is important to note that the color patterns of induced acoustic emission do not represent flow signals.

Sonazoid™ is an ultrasound contrast agent (UCA) consisting of stabilized gas microbubbles in an aqueous suspension. Sonazoid™ has overcome the stability problems of first generation USCA and can produce myocardial perfusion images. Myocardial imaging using ultrasound contrast agents provides diagnosis of chronic heart disease and assessment of the coronary arteries and of the coronary blood flow reserve.
Sonazoid™ is taken up by healthy Kupffer cells in the liver and spleen, but break down in high amplitude ultrasound imaging modes such as color Doppler imaging. The bubble rupture produces a transient pressure wave, which results in a characteristic mosaic color pattern from tissues containing the microbubbles (induced acoustic emission). Liver tumors without Kupffer cells will not display the mosaic pattern and can therefore be identified easily.

Tissue-specific ultrasound contrast agents improve the image contrast resolution through differential uptake. The concentration of microbubble contrast agents within the vasculature, reticulo-endothelial, or lymphatic systems produces an effective passive targeting of these areas. Other contrast media concepts include targeted drug delivery via contrast microbubbles.
Tissue-specific ultrasound contrast agents are injected intravenously and taken up by specific tissues or they adhere to specific targets such as venous thrombosis. These effects may require minutes to several hours to reach maximum effectiveness. By enhancing the acoustic differences between normal and diseased tissues, these tissue-specific agents improve the detectability of abnormalities.
Some microbubbles accumulate in normal hepatic tissue; some are phagocytosed by Kupffer cells in the reticuloendothelial system and others may stay in the sinusoids. Liver tumors without normal Kupffer cells can be identified by the lack of the typical mosaic color pattern of the induced acoustic emission. The hepatic parenchymal phase, which may last from less than an hour to several days, depending on the specific contrast medium used, may be imaged by bubble-specific modes such as stimulated acoustic emission (color Doppler using high MI) or pulse inversion imaging.

Ultrasound at the microbubble resonance frequency can cause bubble rupture at high acoustic power (mechanical index (MI) greater than 0.5). The result is a transient high-amplitude, broadband signal containing all frequencies, not only the harmonics. It will create a strong signal in B-mode or a short-lasting multicolored, mosaic-like effect in color Doppler sonography.
Several terms for this typical signal have been used, e.g. induced or stimulated acoustic emission, loss of correlation imaging and sono-scintigraphy.