Power Doppler sonography is a new technique that displays the strength of the Doppler signal in color, rather than the speed and direction information. It has three times the sensitivity of conventional color Doppler for detection of flow and is particularly useful for small vessels and those with low-velocity flow. Power Doppler sonography shows potential for detecting areas of ischemia in the kidney, brain, and prepubertal testis and for demonstrating hyperemia in areas of inflammation. Its increased sensitivity to motion and flash artifact, however, limits its application in children. Power Doppler is useful as an adjunct to conventional color and pulsed Doppler sonography.