title: Production of microbubbles for use as echo contrast agents.
abstract: A variety of agents have been proposed for use as contrast for ultrasound studies. Several reports suggest the use of microbubbles because of their superior sonographic resolution. We describe a method of producing calibrated microbubbles utilizing differential absorption and gas injection techniques. Gas injection methods are described using a Plexiglas microbubbler apparatus with a fine needle orifice. The bubbles originally produced by this device are in a size range of 40-100 microns and consist of nitrogen (10%) and carbon dioxide (90%). The differential absorption technique uses THAM [tris(hydroxymethyl)aminomethane hydrochloride] to absorb the carbon dioxide (diluent gas) from the bubbles selectively, leaving smaller microbubbles. The microbubbles can be calibrated using the electric gating principle of the Coulter Counter.
mesh_terms: D001639:Bicarbonates / Q000378:metabolism; D002138:Calibration; D002245:Carbon Dioxide / Q000378:metabolism; D003287:Contrast Media; D005740:Gases; D006801:Humans; D008433:Mathematics; D009584:Nitrogen / Q000378:metabolism; D012996:Solutions; D014465:Ultrasonics / Q000295:instrumentation; D014463:Ultrasonography / Q000379:methods*
chemical_list: D001639:Bicarbonates; D003287:Contrast Media; D005740:Gases; D012996:Solutions; D002245:Carbon Dioxide; D009584:Nitrogen