Ultrasound contrast materials

Research in the field of ultrasound contrast materials will develop in two basic directions - the simple and the complex . The simple would mean wider clinical application of the store of available (or to-be-approved) contrast agents in clinical diagnostics. The success will depend not only on the quality of the new diagnostic procedures and results of the clinical trials with new ultrasound... 

The ultrasound contrast agents are manufactured from nontoxic natural or synthetic biodegradable materials (e.g., lipids or proteins), and a small amount of an inert low-solubility non-reactive gas (e.g., perfluorocarbon). These components have been shown to be harmless to the patient unlike the tens of milliliters of concentrated viscous solutions of the widely used X-ray contrast agents (which may sometimes result in nephrotoxicity). 

Particulate agents (especially gas-filled microbubble materials) are currently approached with caution by physicians, regulatory agencies and industry marketing, despite the fact that by 2001, perhaps up to 100,000 patients (a rough estimate) will have received ultrasound contrast agents with very few (mostly minor) side effects manifested. 

Albunex was claimed to be the first ultrasound contrast agent capable of myocardial opacification after intravenous injection [16],but very large doses of the material had to be applied. 

Sono Vue (BRl) is an ultrasound contrast medium that consists of microbubbles containing sulfur hexafluoride gas stabilized by phospholipids. The diameter of each microbubble is 2.5 pm and there are about 0.5 x 10 microbubbles/ml. It is isotonic with human plasma, has the same viscosity as blood, and has minimal antigenic potential, since it contains no protein material. 

Ultrasound contrast agents contain microbubbles of air, nitrogen or fluorocarbon gas coated with a thin shell of material such as albumin, galactose, or lipid. They have an markedly different acoustic impedance compared with blood or tissue. The contrast is usually injected intravenously and must measure less than 7 pm if they are to cross the lungs and reach the arterial circulation. They remain intact for only a short time. 

Ultrasound contrast agents contain microbubbles of air, nitrogen, or fluorocarbon gas, coated with a thin shell of material such as... 

Hewlett DC, Greenwood KL, Jarosz JM et al (1997) The incidence of transient medullary hyperechogenicity in neonatal ultrasound examination. Br J Radiol 70 140-143 Huber W, Eckel F, Henning M et al (2006) Prophylaxis of contrast material-induced nephropathy in patients in intensive care acetylcysteine, theophylline, or both A randomized study. Radiology 239 793-804 Huet F, Semama D, Grimaldi M et al (1995) Effects of theophylline on renal insufficiency in neonates with respiratory distress syndrome. Intensive Care Med 21 511-514 Kaplan BS, Restaino I, Raval DS et al (1994) Renal failure in the neonate associated with in utero exposure to nonsteroidal anti-inflammatory agents. Pediatr Nephrol 8 700-704... 

Application ultrasound has been used for the synthesis of materials, coating carbon nanotubes and noble metals, destruction and fragmentation of contrast agents, gas release, polymer destruction, and in drug delivery. i Ultrasound application has effect on permeability of PEC microcapsules. 

---