title: The Doppler kinetics of microbubble echo contrast.
abstract: The right and left heart kinetics of a saccharide-based microbubble echo contrast agent were measured in 11 anesthetized dogs using Doppler intensity as a measure of microbubble concentration while controlling for the dose administered, weight of the subject and cardiac output. A two-phase Doppler time-intensity curve was noted in all vascular regions. A brief first pass effect (phase 1) was found to depend on the contrast dose, cardiac output and subject size. This was followed by a much longer nearly steady-state elevation in the Doppler intensity compared with baseline (phase 2). The kinetics of phase 2 were found to be the same in all vascular distributions and independent of cardiac output. The phase 2 kinetics depend on the contrast dose, subject size and elimination characteristics of the contrast agent. The clinically important conclusions are: (1) the magnitude of Doppler enhancement and duration of the contrast effect can be predicted using the simple formulas presented; (2) the flow-dependent portion of the arterial contrast effect is effectively over only a few seconds after intravenous injection; and (3) the kinetics of phase 2 are the same throughout the body.
authors.affiliation: University of Rochester, NY, USA. karlschwarz@echocardio.medicine.rochester.edu
authors.forename: K Q
authors.initials: KQ
authors.lastname: Schwarz
authors.forename: X
authors.initials: X
authors.lastname: Chen
authors.forename: G P
authors.initials: GP
authors.lastname: Bezante
authors.forename: D
authors.initials: D
authors.lastname: Phillips
authors.forename: R
authors.initials: R
authors.lastname: Schlief
mesh_terms: D000818:Animals; D002302:Cardiac Output; D003287:Contrast Media / Q000493:pharmacokinetics*; D004285:Dogs; D018619:Echocardiography, Doppler, Pulsed / Q000379:methods*; D005260:Female; D005263:Femoral Artery / Q000000981:diagnostic imaging / Q000378:metabolism*; D006439:Hemodynamics; D007275:Injections, Intravenous; D008943:Mitral Valve / Q000000981:diagnostic imaging / Q000378:metabolism*; D011134:Polysaccharides / Q000493:pharmacokinetics*; D011651:Pulmonary Artery / Q000000981:diagnostic imaging / Q000378:metabolism*
chemical_list: D003287:Contrast Media; D011134:Polysaccharides; C059891:SHU 508