title: Enhancement of the echogenicity of flowing blood by the contrast agent perflubron.
abstract: OBJECTIVE
  Perflubron, or perfluorooctylbromide, is an effective ultrasound and computed tomography contrast agent in a lecithin emulsion form. The authors studied acoustical properties of perflubron emulsion in static human and flowing porcine blood for concentrations from 0% to 30% weight per volume.
  
  
  METHODS
  Propagation velocity (c), the intensity attenuation coefficient (mu), density (rho), and particle size were measured directly. Because the backscatter of flowing blood is dependent on shear rate, relative echogenicity was measured as a function of perflubron concentration in whole porcine blood, in a laminar flow system, at shear rates of 16.0 to 68.5 sec-1 for realtime sector scanner images obtained at 7.5 MHz.
  
  
  RESULTS
  Neat perflubron is a colorless liquid with density of 1.93 g.mL-1 and velocity of 630 m.sec-1. The following values were obtained at 4.7 MHz in static human blood (hematocrit 44%) at expected human in vivo blood concentrations of 3.1% perflubron versus pure human blood: rho = 1.11 versus 1.05 g.mL-1, c = 1,480 versus 1,576 m.sec-1, mu = 1.00 versus 0.36 dB.cm-1. The mean echogenicity of whole porcine blood increased substantially with perflubron concentration and was inversely proportional to blood shear rate.
  
  
  CONCLUSIONS
  Adding 3.1% concentration of perflubron increased image echogenicity at all shear rates studied, ranging from 70% at 68.5 sec-1 (16.3 cm.sec-1) up to 180% at 16.0 sec-1 (3.8 cm.sec-1). Perflubron enhancement of blood is marked and demonstrates shear rate dependence like that of whole blood.
authors.affiliation: Department of Radiology, Veterans Affairs Medical Center, San Diego, California 92161.
authors.forename: M P
authors.initials: MP
authors.lastname: André
authors.forename: G
authors.initials: G
authors.lastname: Steinbach
authors.forename: R F
authors.initials: RF
authors.lastname: Mattrey
mesh_terms: D001783:Blood Flow Velocity; D003287:Contrast Media; D005466:Fluorocarbons; D006801:Humans; D006842:Hydrocarbons, Brominated; D007089:Image Enhancement; D008955:Models, Cardiovascular; D008961:Models, Structural; D014463:Ultrasonography
chemical_list: D003287:Contrast Media; D005466:Fluorocarbons; D006842:Hydrocarbons, Brominated; C003072:perflubron