[Duplex sonography diagnosis of deep leg- and pelvic vein thromboses]

The diagnosis of thrombosis of the deep leg veins or pelvic veins is usually established on the basis of technical procedures. Clinical signs such as swelling, erythema or warming are unreliable. Plethysmographic measures have a low specificity, nuclear medicine studies enable assessment, limited to the lower leg, only after 24 hours. Continuous-wave Doppler sonography, as is the case with plethysmography, does not allow differentiation between intra- or extravascular cause of the obstruction to flow; hemodynamically-unimportant, floating thrombi cannot be detected. Ascending phlebography is an invasive procedure exposing the patient to contrast medium with its possible allergic reactions, radiation and thrombosis or local inflammation. Duplex-sonography enables the combination of high-resolution ultrasonic B-imaging with a pulsed Doppler unit which provides a noninvasive means for direct visualization of the involved vessel. For the examination, preferably, linear scanners are employed with a frequency of at least 5 megahertz. With the patient in the supine position, first, the iliac vein, medial to the artery, is imaged, then the common femoral vein and the great saphenous vein (Figure 1). Then the patient is turned and the popliteal vein and, as far as possible, the veins of the lower leg are examined from the back. Direct proof of thrombosis is considered the documentation of intraluminal echo-intense structures (Figure 2) associated with absence of complete compressibility of the vascular lumen in cross-section with slight pressure of the transducer (Figures 3a and 3b).(ABSTRACT TRUNCATED AT 250 WORDS)