Color Doppler energy: computer analysis of color to assess angle dependency and detection of volume flow differences

The aims of this study were to assess (1) any angle dependency of color Doppler energy and (2) if computer analysis of the color can distinguish variations in volume flow. Fluid flowing through a silicon tube in a waterbath was insonated and the color in the images analyzed by a computer. The color presentation on the screen decreases rapidly as the angle approaches 90 degrees. At angles that did not produce a saturation of the color in the tube, the computer analysis detected significant differences between different flow volumes. We have concluded that monitoring of volume flow changes by analysis of color Doppler energy is possible, but the angle of insonation must be taken into account.