Parametric imaging for myocardial contrast echocardiography: Pixel-by-pixel incorporation of information from both spatial and temporal domains

Ultrasound can be used to destroy microbubbles during their continuous infusion, and their rate of myocardial replenishment can be measured by progressively increasing the pulsing interval (PI). We have developed an algorithm that incorporates information from both the spatial and temporal domains. The pre-contrast images and contrast-enhanced images are selected from images acquired for each pulsing interval. Images are aligned, averaged, and subtracted. Video-intensity (VI) is measured in each pixel, and the resulting PI versus VI plot for each pixel is fitted to an exponential function: y=A(l-e^-βt) , where y is VI at PI t, A represents microvascular cross-sectional area, β represents the mean microbubble velocity, and A·β represents myocardial blood flow. These values are represented in color as separate parametric images. This new method offers a simple and easy means for assessing the spatial and temporal characteristics of myocardial perfusion during MCE.