ECHOCARDIOGRAPHY OF REGIONAL MYOCARDIAL PERFUSION

During my years of training and practice, I have become convinced that a
significant amount of scientific work has to be done in the field of
clinical medicine to make its practice more objective and thus ultimately
more useful. One of the areas that has interested me is regional
myocardial perfusion and function and the inadequacy of coronary
angiography in determining the significance of coronary stenosis. During
my work with myocardial contrast agents, I became interested in their
potential use for determining absolute regional myocardial perfusion. In
addition, if the current limitations inherent in the quantitative
assessment of regional myocardial function could be overcome,
two-dimensional echocardiography would become an ideal and readily
available tool for simultaneously assessing regional myocardial perfusion
and function. This proposal deals in detail with what I think has to be investigated in
order for myocardial contrast echocardiography to become a suitable
modality for measuring regional perfusion and function. The relationship
between contrast effect and blood flow has to be established; the effect of
size and distribution of microbubbles on myocardial contrast effect has to
be determined; the fate of microbubbles in the microvasculature has to be
studied and the effect of these bubbles on the microvasculature has to be
documented; the agent producing the least reactive hyperemic response has
to be identified and its toxicity in intact animal and man studied.
Finally, preliminary work has to be attempted in humans demonstrating
significant advantages over currently available techniques of measuring
myocardial blood flow. After developing a new algorithm for measuring
regional myocardial function, studies involving flow-function relationships
have to be performed.