Colour ultrasound imaging of blood flow and tissue motion.

The authors present a preliminary report to demonstrate a new color Doppler (CD) ultrasonography (US) technique called power Doppler (PD), which displays the total integrated Doppler power in color, and to compare PD with CD imaging, which generally displays an estimate of the mean Doppler frequency shift. Two standard commercial US scanners that encode the integrated power in the Doppler signal in color were used to demonstrate PD. A standard nonflow-containing US phantom, a normal right kidney, and a torsive and normal contralateral testis were scanned in the power mode. In the phantom and kidney, results with CD and PD were directly compared. PD does not alias, is relatively angle independent, and displays background noise in a way that increases the usable dynamic range of a US scanner. This extended dynamic range should increase machine sensitivity and may demonstrate increased flow in certain circumstances. PD is a new CD imaging imaging mode that might be superior to CD in some cases.