What is microbubble ultrasound?
Microbubbles are used for contrast ultrasound imaging as blood-pool agents in cardiology and radiology. Their promise as targeted agents for molecular imaging is now being recognized. Microbubbles can be functionalized with ligand molecules that bind to molecular markers of disease.
Why are microbubbles used in ultrasound?
Microbubbles, when used as ultrasound contrast agents, can act as echo-enhancers and therapeutic agents, and they can play an essential role in ultrasound imaging and ultrasound-mediated therapy. Recently, various types of ultrasound contrast agents made of lipid, polymer, and protein shells have been used.
What are microbubble agents?
Microbubbles are intravenous contrast agents used in contrast-enhanced ultrasound. Microbubble contrast agent is different to the agitated saline contrast agent often used in echocardiographic studies. Microbubbles consist of a gas surrounded by a lipid, lipopolymer, or polymer shell. They range from 2-10 µm.
What is microbubble cavitation?
One of the effects of ultrasound is cavitation, or microbubble formation and collapse. Cavitation produces high pressures and temperatures, and microbubble expansion and then collapse close to cells can lead to cellular damage or hemorrhage in biological tissues.
How do Nanobubbles work?
Nanobubbles naturally adhere to suspended, colloidal, and emulsified materials, causing them to clump together so they can be easily removed from water by filtration or flotation.
What diagnostic procedures are microbubbles used for?
Microbubbles are also routinely used to evaluate myocardial perfusion and heart function and to diagnose vesicoureteric reflux. Over the last few years the sensitivity and specificity of ultrasound devices to detect microbubbles has improved steadily.
What contrast agent is used in ultrasound imaging?
SonoVue is a purely intravascular contrast agent, therefore it allows assessment of the vascularity and non-specific contrast agent retention of lesions. Due to its widespread approval, it is by far the most commonly utilised ultrasound contrast agent currently.
How big is a microbubble?
The diameter of a microbubble is approximately equal to the size of a red blood cell (less than ~10 μm diameter), which allows it to display similar rheology in the microvessels and capillaries throughout the body.
How are nanobubbles generated?
Nanobubbles are frequently generated in solutions by creating cavities. Cavitation is caused by pressure reduction below the certain critical value.
How nanobubbles are generated?
Micro-nanobubble and Nanobubble generators utilize pressurized dissolution, electrolysis or by swirling fluids in a mixing chamber and then feeding the fluids through a single shear point, injector, or venturi to produce air bubbles having a mean particle size of >200 nm.
How are microbubbles administered?
Microbubble agents are typically injected intravenously, usually in a solution diluted with physiological saline. These bubbles may be injected as a slow bolus, or a continuous infusion. The slow bolus injection shows rapid first pass on time–intensity curves, slower clearance and a dose-dependent contrast enhancement.
How does ultrasound-microbubble drug delivery work?
Since microbubbles undergo cavitation only in the presence of an ultrasound field, the delivery is highly targeted towards the specific area of insonation, thus reducing off-target effects. Open in a separate window Figure 2 Basic principle of ultrasound-microbubble (USMB)-mediated drug and gene delivery.
Can ultrasound and Microbubbles be used to deliver cargo to the lung?
Despite the abundant literature describing ultrasound and microbubbles for cargo delivery across the blood–brain barrier or to tumors, there are very few reports of the technique in the lung.
Is ultrasound-microbubble therapy the future of endothelium therapy?
Over the past two decades, ultrasound-microbubble (USMB)-mediated intracellular drug and gene delivery has emerged as a promising therapeutic approach for the treatment of the endothelium.
What factors affect the delivery capacity of an ultrasound machine?
Bubble size is another important property that contributes to delivery capacity. In comparison to larger bubbles, smaller bubbles require higher ultrasound frequencies to undergo inertial cavitation [164].