Doppler quantification of echo-contrast injections in vivo.
It is difficult to quantify myocardial perfusion using contrast echocardiography because the echogenicity of injected contrast is unknown. We propose that a measurement of Doppler amplitude from blood in a systemic artery during the passage of contrast could define the needed input function. Time-amplitude curves from pulsed Doppler cuffs on coronary and carotid arteries of 7 dogs were analyzed during aortic root and left atrial injections of Albunex. We found in individual animals that the areas under the Doppler time-amplitude curves were correlated to the amount of Albunex injected (R = 0.87-0.99), inversely correlated to cardiac output (R = 0.83), and uncorrelated to coronary flow (R = 0.18). Due to better mixing, the coronary and carotid response areas correlated better for left atrial injections (R = 0.96) than for aortic root injections (R = 0.56). We conclude that Doppler amplitude detection can be used to quantify the passage of echo-contrast agents, that the measurements comply with indicator-dilution principles, and that systemic measurements in the carotid artery could be used to predict the coronary input function for injection sites with good systemic mixing.
Hartley
C J
CJ
Department of Medicine, Baylor College of Medicine, Houston, TX 77030.
Cheirif
J
J
Collier
K R
KR
Bravenec
J S
JS
Mickelson
J K
JK
D000418:Albumins; D000818:Animals; D003287:Contrast Media; D003326:Coronary Circulation; D004285:Dogs; D015150:Echocardiography, Doppler / Q000379:methods*; D007275:Injections, Intravenous; D008297:Male; D008833:Microcirculation; D008863:Microspheres
D000418:Albumins; C060687:Albunex; D003287:Contrast Media