title: Microbubble responses to a similar mechanical index with different real-time perfusion imaging techniques.
abstract: The purpose of this study was to determine differences in contrast enhancement and microbubble destruction rates with current commercially available low-mechanical index (MI) real-time perfusion imaging modalities. A tissue-mimicking phantom was developed that had vessels at 3 cm (near field) and 9 cm (far field) from a real-time transducer. Perfluorocarbon-exposed sonicated dextrose albumin microbubbles (PESDA) were injected proximal to a mixing chamber, and then passed through these vessels while the region was insonified with either pulses of alternating polarity with pulse inversion Doppler (PID) or pulses of alternating amplitude by power modulation (PM) at MIs of 0.1, 0.2 and 0.3. Effluent microbubble concentration, contrast intensity and the slope of digital contrast intensity vs. time were measured. Our results demonstrated that microbubble destruction already occurs with PID at an MI of 0.1. Contrast intensity seen with PID was less than with PM. Therefore, differences in contrast enhancement and microbubble destruction rates occur at a similar MI setting when using different real-time pulse sequence schemes.
authors.affiliation: Section of Cardiology, Department of Internal Medicine, University of Nebraska Medical Center, Omaha NE 68198-1165, USA. trporter@unmc.edu
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Porter
authors.forename: Joseph
authors.initials: J
authors.lastname: Oberdorfer
authors.forename: Patrick
authors.initials: P
authors.lastname: Rafter
authors.forename: John
authors.initials: J
authors.lastname: Lof
authors.forename: Feng
authors.initials: F
authors.lastname: Xie
mesh_terms: D000162:Acoustics; D003287:Contrast Media; D004452:Echocardiography / Q000379:methods*; D015150:Echocardiography, Doppler / Q000379:methods; D006801:Humans; D045423:Microbubbles; D019047:Phantoms, Imaging; D014159:Transducers
chemical_list: D003287:Contrast Media