[Color-coded Doppler sonography of renal vessels in childhood. I. Method and normal values].

Doppler sonography allows measurement of renal blood flow velocities non invasively. Combination of pulsed Doppler with gray scale imaging (Duplex-scan) yields precise measurement of the flow in defined vessels. By means of the Duplex technique not only the flow parameters in the renal artery and vein can be measured, but also in the segmental, interlobar and interlobular arteries and veins. Colour coded Doppler sonography allows simultaneous display of the flow within the vessels and the gray scale image. With the help of colour coded Doppler sonography the sample volume of the pulsed Doppler device can be placed precisely within the vessels, which makes possible the determination of absolute flow velocities. Besides the flow velocities other different indices have been defined in the literature. All indices result from comparison of systolic and diastolic flow amplitudes in different ways. The flow parameters in the renal vessels are dependent on the site of the flow measurement and the age of the children. When pathologic flow parameters are analyzed the vessel and the age of the child have to be mentioned always. The interpretation of pathologic flow profiles becomes easier by knowledge of normal values for the flow velocities and the different indices.