Quantison, consisting of air-filled microbubbles with stiff and rigid human serum albumin shells, is an investigational ultrasound contrast agent for the assessment of coronary artery disease.
The stiff shell inhibits the bubbles from oscillating and decrease non-linear scattering. Quantison is capable of long lasting cavity contrast and myocardial opacification using intermittent imaging.

Diagnostic ultrasound imaging has no known risks or long-term side effects. Discomfort to the patient is very rare if the sonogram is accurately performed by using appropriate frequencies and intensity ranges. However, the application of the ALARA principle is always recommended.
There are reports of low birth weight of babies after applying more than the recommended ultrasound examinations during pregnancy. Women who think they might be pregnant should raise this issue with the doctor before undergoing an abdominal ultrasound, to avoid any harm to the fetus in the early stages of development.
Since ultrasound is energy, sensitive tissues like the reproductive organs could possibly sustain damage if vibrated to a high degree by too intense ultrasound waves. In diagnostic ultrasonic procedures, such damage would only result from improper use of the equipment.

Possible ultrasound bioeffects:
The thermal effect is controlled by the displayed thermal index and the mechanical index indicates the risk of cavitation.
An ultrasound gel is applied to obtain better contact between the transducer and the skin. This has the consistency of thick mineral oil and is not associated with skin irritation or allergy.
Specific conditions for which ultrasound may be selected as a treatment may be attached with higher risks.

See also Ultrasound Imaging Procedures, Fetal Ultrasound and Obstetric and Gynecologic Ultrasound.

SonoGen (QW7437) is an anionically charged 2% perfluorocarbon emulsion under development as a transpulmonary myocardial ultrasound contrast agent (UCA). The SonoGen microbubbles have a reduced adherence to the negatively charged vascular endothelium and reduced coalescence. SonoGen, a second generation USCA has the theoretical potential to provide high safety and efficacy and improved tissue grayscale persistence compared to first generation fluorocarbon contrast agents.

From Bayer Schering Pharma AG:
Sonovist® (sometimes found as Sonavist) is an investigational ultrasound contrast agent with a biodegradable synthetic capsule filled with sulphur hexafluoride. The biodegradable shell of Sonovist is so stable that it can be taken up by Kupffer cells of the reticuloendothelial system or accumulate in the sinusoids.
Therefore, Sonovist® has an additional hepato-splenic parenchymal phase following the blood pool phase, analog to the superparamagnetic iron oxide agents used in liver MRI. The microbubbles are stationary in this phase and generate no conventional Doppler signals. This tissue-specific phase has a variable duration and can be imaged by bubble specific imaging modes.

Submicron ultrasound contrast agents are gas-filled, double-walled microspheres with a diameter smaller than 1 μm that rupture when exposed to ultrasound energy at megahertz frequencies. These agents differ from traditional ultrasound contrast microbubbles in that the submicron bubbles may serve as extravascular agents. They are small enough to travel through the lymphatic system and to be extravasated from tumor neovasculature. The detection of these agents is limited by their hard shell, which requires high-pressure ultrasound insonation for shell rupture and excitation of the gas bubble. After shell rupture, the gas diffuses rapidly from submicron sized agents. The optimal processing of each echo is important.