Untargeted<unk>  is currently applied in echocardiography and radiology. Targeted<unk>  is being developed for a variety of medical applications. Untargeted<unk>  Untargeted microbubbles like Optison and Levovist are currently used in echocardiography. In addition, SonoVue<unk> <unk>  agent is used in radiology for lesion characterization. * Organ Edge Delineation: microbubbles can<unk> the<unk>  at the interface between the tissue and blood. A clearer picture of this interface gives the clinician a better picture of the structure of an organ. Tissue structure is crucial in echocardiograms, where a thinning, thickening, or irregularity in the heart wall indicates a serious heart condition that requires either monitoring or treatment. * Blood Volume and Perfusion:<unk>  holds the promise for (1) evaluating the degree of blood perfusion in an organ or area of interest and (2) evaluating the blood volume in an organ or area of interest. When used in conjunction with Doppler<unk> , microbubbles can measure myocardial flow rate to diagnose valve problems. And the relative intensity of the microbubble echoes can also provide a quantitative estimate on blood volume. * Lesion Characterization:<unk>  plays a role in the differentiation between benign and malignant focal liver lesions. This differentiation relies on the observation or processing of the dynamic vascular pattern in a lesion with respect to its surrounding tissue parenchyma. Targeted<unk>  * Inflammation:<unk>  agents may be designed to bind to certain proteins that become expressed in inflammatory diseases such as Crohn's disease, atherosclerosis, and even heart attacks. Cells of interest in such cases are endothelial cells of blood vessels, and leukocytes: * The inflamed blood vessels specifically express certain receptors, functioning as cell adhesion molecules, like VCAM-1, ICAM-1, E-selectin. If microbubbles are targeted with ligands that bind these molecules, they can be used in<unk>  echocardiography to detect the onset of inflammation. Early detection allows the design of better treatments. Attempts have been made to outfit microbubbles with monoclonal antibodies that bind P-selectin, ICAM-1, and VCAM-1, but the adhesion to the molecular target was poor and a large fraction of microbubbles that bound to the target rapidly detached, especially at high shear stresses of physiological relevance. * Leukocytes possess high adhesion efficiencies, partly due to a dual-ligand selectin-integrin cell arrest system. One ligand:receptor pair (PSGL-1:selectin) has a fast bond on-rate to slow the leukocyte and allows the second pair (integrin:immunoglobulin superfamily), which has a slower on-rate but slow off-rate to arrest the leukocyte, kinetically enhancing adhesion. Attempts have been made to make<unk>  agents bind to such ligands, with techniques such as dual-ligand targeting of distinct receptors to polymer microspheres, and biomimicry of the leukocyte's selectin-integrin cell arrest system, having shown an increased adhesion efficiency, but yet not efficient enough to allow clinical use of targeted<unk>  for inflammation. * Thrombosis and thrombolysis: Activated platelets are major components of blood clots (thrombi). Microbubbles can be conjugated to a recombinant single-chain variable fragment specific for activated glycoprotein IIb/IIIa (GPIIb/IIIa), which is the most abundant platelet surface receptor. Despite the high shear stress at the thrombus area, the GPIIb/IIIa-targeted microbubbles will specifically bind to activated platelets and allow real-time molecular imaging of thrombosis, such as in myocardial infarction, as well as monitoring success or failure of pharmacological thrombolysis. * Cancer: cancer cells also express a specific set of receptors, mainly receptors that encourage angiogenesis, or the growth of new blood vessels. If microbubbles are targeted with ligands that bind receptors like VEGF or activated glycoprotein IIb/IIIa, they can non-invasively and specifically identify areas of cancers. * Gene Delivery: Vector DNA can be conjugated to the microbubbles. Microbubbles can be targeted with ligands that bind to receptors expressed by the cell type of interest. When the targeted microbubble accumulates at the cell surface with its DNA payload,<unk>  can be used to burst the microbubble. The force associated with the bursting may temporarily permeablize surrounding tissues and allow the DNA to more easily enter the cells. Targeted theranostic microbubbles (directed at VCAM-1) have been employed to deliver miR126 in a preclinical setting to stop the development of AAA in vivo. * Drug Delivery: drugs can be incorporated into the microbubble's lipid shell. The microbubble's large size relative to other drug delivery vehicles like liposomes may allow a greater amount of drug to be delivered per vehicle. By targeted the drug-loaded microbubble with ligands that bind to a specific cell type, microbubble will not only deliver the drug specifically, but can also provide verification that the drug is delivered if the area is imaged using<unk> .
Contrast-enhanced ultrasound
Phase contrast magnetic resonance imaging
Radionuclide angiography
Angiography
Fluoroscopy
Angiology
Contrast CT
Magnetic resonance angiography