TY - JOUR
T1 - Quantification of myocardial blood flow with ultrasound-induced destruction of microbubbles administered as a constant venous infusion
AU - Wei, Kevin
AU - Jayaweera, Ananda R.
AU - Firoozan, Soroosh
AU - Linka, Andre
AU - Skyba, Danny M.
AU - Kaul, Sanjiv
PY - 1998/2/10
Y1 - 1998/2/10
N2 - Background-Ultrasound can cause microbubble destruction. If microbubbles are administered as a continuous infusion, then their destruction within the myocardium and measurement of their myocardial reappearance rate at steady state will provide a measure of mean myocardial microbubble velocity. Conversely, measurement of their myocardial concentration at steady state will provide an assessment of microvascular cross-sectional area. Myocardial blood flow (MBF) can then be calculated from the product of the two. Methods and Results-Ex vivo and in vitro experiments were performed in which either flow was held constant and pulsing interval (interval between microbubble destruction and replenishment) was altered, or vice versa. In vivo experiments were performed in 21 dogs. In group 1 dogs (n=7), MBF was mechanically altered in a model in which coronary blood volume was constant. In group 2 dogs (n=5), MBF was altered by direct coronary infusions of vasodilators. In group 3 dogs (n=9), non-flow-limiting coronary stenoses were created, and MBF was measured before and after the venous administration of a coronary vasodilator. In all experiments, microbubbles were delivered as a constant infusion, and myocardial contrast echocardiography was performed using different pulsing intervals. The myocardial video intensity versus pulsing interval plots were fitted to an exponential function: y=A(1-e(- βt)), where A is the plateau video intensity reflecting the microvascular cross-sectional area, and β reflects the rate of rise of video intensity and, hence, microbubble velocity. Excellent correlations were found between flow and β, as well as flow and the product of A and β. Conclusions-MBF can be quantified with myocardial contrast echocardiography during a venous infusion of microbubbles. This novel approach has potential for measuring tissue perfusion in any organ accessible to ultrasound.
AB - Background-Ultrasound can cause microbubble destruction. If microbubbles are administered as a continuous infusion, then their destruction within the myocardium and measurement of their myocardial reappearance rate at steady state will provide a measure of mean myocardial microbubble velocity. Conversely, measurement of their myocardial concentration at steady state will provide an assessment of microvascular cross-sectional area. Myocardial blood flow (MBF) can then be calculated from the product of the two. Methods and Results-Ex vivo and in vitro experiments were performed in which either flow was held constant and pulsing interval (interval between microbubble destruction and replenishment) was altered, or vice versa. In vivo experiments were performed in 21 dogs. In group 1 dogs (n=7), MBF was mechanically altered in a model in which coronary blood volume was constant. In group 2 dogs (n=5), MBF was altered by direct coronary infusions of vasodilators. In group 3 dogs (n=9), non-flow-limiting coronary stenoses were created, and MBF was measured before and after the venous administration of a coronary vasodilator. In all experiments, microbubbles were delivered as a constant infusion, and myocardial contrast echocardiography was performed using different pulsing intervals. The myocardial video intensity versus pulsing interval plots were fitted to an exponential function: y=A(1-e(- βt)), where A is the plateau video intensity reflecting the microvascular cross-sectional area, and β reflects the rate of rise of video intensity and, hence, microbubble velocity. Excellent correlations were found between flow and β, as well as flow and the product of A and β. Conclusions-MBF can be quantified with myocardial contrast echocardiography during a venous infusion of microbubbles. This novel approach has potential for measuring tissue perfusion in any organ accessible to ultrasound.
KW - Blood flow
KW - Contrast media
KW - Echocardiography
KW - Microcirculation
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U2 - 10.1161/01.CIR.97.5.473
DO - 10.1161/01.CIR.97.5.473
M3 - Article
C2 - 9490243
AN - SCOPUS:0032501992
SN - 0009-7322
VL - 97
SP - 473
EP - 483
JO - Circulation
JF - Circulation
IS - 5
ER -