[Assessment of the leg veins using duplex ultrasonography]

Duplex scanning, first used for the investigation of arterial diseases, is characterized by the combination of B-Mode ultrasound and spectral analysis or color imaging of PW-Doppler signals. This provides information on both the morphology of the vessel and the corresponding hemodynamics. Compared to the conventional noninvasive techniques in phlebology such as plethysmography and CW-Doppler its major advantage is the additional morphologic information. Until now this anatomical information was only available by invasive phlebography. This technique, however, gives only limited informations on hemodynamics. Using an appropriate technique of duplex scanning, the deep veins from the calf to V. cava as well as the superficial veins and the perforators can be examined. In the hand of a skilled investigator deep vein thrombosis can be diagnosed with accuracy. Compared to the gold standard phlebography sensitivity and specificity are high: 96% and 99% resp. The duplex technique is also very reliable in differentiating the diagnosis of deep vein thrombosis: Baker's cysts, hematomas and tumors usually are easily detected by B-scan. Investigation of chronic venous insufficiency is also possible by duplex-scanning. Imaging of the veins and pulsed Doppler analysis allows to determine whether the reflux is in the deep or superficial system. On a more scientific field duplex allows the precise noninvasive determination of hemodynamic parameters. Thus it is possible to measure physiologic venous hemodynamics and to quantify drug effectiveness. Duplex sonography holds a key position in the phlebological diagnostic procedure. This new technique causes no harm to the patient and important information is obtained at relative low costs.