title: Broadband attenuation measurements of phospholipid-shelled ultrasound contrast agents.
abstract: The aim of this study was to characterize the frequency-dependent acoustic attenuation of three phospholipid-shelled ultrasound contrast agents (UCAs): Definity, MicroMarker and echogenic liposomes. A broadband through-transmission technique allowed for measurement over 2 to 25 MHz with a single pair of transducers. Viscoelastic shell parameters of the UCAs were estimated using a linearized model developed by N. de Jong, L. Hoff, T. Skotland and N. Bom (Ultrasonics 1992; 30:95-103). The effect of diluent on the attenuation of these UCA suspensions was evaluated by performing attenuation measurements in 0.5% (w/v) bovine serum albumin and whole blood. Changes in attenuation and shell parameters of the UCAs were investigated at room temperature (25°C) and physiologic temperature (37°C). The attenuation of the UCAs diluted in 0.5% (w/v) bovine serum albumin was found to be identical to the attenuation of UCAs in whole blood. For each UCA, attenuation was higher at 37°C than at 25°C, underscoring the importance of conducting characterization studies at physiologic temperature. Echogenic liposomes exhibited a larger increase in attenuation at 37°C versus 25°C than either Definity or MicroMarker.
authors.affiliation: Biomedical Engineering Program, University of Cincinnati, Cincinnati, Ohio, USA. Electronic address: raymonjl@mail.uc.edu.
authors.forename: Jason L
authors.initials: JL
authors.lastname: Raymond
authors.affiliation: Biomedical Engineering Program, University of Cincinnati, Cincinnati, Ohio, USA; Division of Cardiovascular Diseases, Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, USA.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Haworth
authors.affiliation: Division of Cardiovascular Diseases, Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, USA.
authors.forename: Kenneth B
authors.initials: KB
authors.lastname: Bader
authors.affiliation: Biomedical Engineering Program, University of Cincinnati, Cincinnati, Ohio, USA.
authors.forename: Kirthi
authors.initials: K
authors.lastname: Radhakrishnan
authors.affiliation: Biomedical Engineering Program, University of Cincinnati, Cincinnati, Ohio, USA.
authors.forename: Joseph K
authors.initials: JK
authors.lastname: Griffin
authors.affiliation: Division of Cardiology, Department of Internal Medicine, University of Texas Health Science Center at Houston, Houston, Texas, USA.
authors.forename: Shao-Ling
authors.initials: SL
authors.lastname: Huang
authors.affiliation: Division of Cardiology, Department of Internal Medicine, University of Texas Health Science Center at Houston, Houston, Texas, USA.
authors.forename: David D
authors.initials: DD
authors.lastname: McPherson
authors.affiliation: Biomedical Engineering Program, University of Cincinnati, Cincinnati, Ohio, USA; Division of Cardiovascular Diseases, Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, USA.
authors.forename: Christy K
authors.initials: CK
authors.lastname: Holland
mesh_terms: D020099:Coated Materials, Biocompatible / Q000737:chemistry; D003287:Contrast Media / Q000737:chemistry*; D005466:Fluorocarbons / Q000737:chemistry*; D019047:Phantoms, Imaging; D010743:Phospholipids / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014463:Ultrasonography / Q000295:instrumentation / Q000379:methods*
chemical_list: D020099:Coated Materials, Biocompatible; D003287:Contrast Media; D005466:Fluorocarbons; D010743:Phospholipids; C042852:perflutren
keywords: Broadband characterization; Definity; Echogenic liposomes; MicroMarker; Microbubbles; Polyvinylidene fluoride transducer; Size distribution; Ultrasound contrast agents