[Technological diagnosis of venous thrombosis]

The bedside diagnosis of deep venous thrombosis is not accurate enough to implement invasive therapy, e.g., systemic administration of thrombolytic agents, so the diagnosis must be established by independent diagnostic means. The most useful diagnostic tests available include Doppler ultrasound, duplex sonography, color duplex sonography, and contrast venography. The common femoral vein and popliteal vein can be examined easily with a Doppler ultrasound probe. Reduced blood flow due to major venous thrombosis proximal or distal to the probe, qualitative blood flow and flow direction are all detectable. Duplex sonography allows imaging of thrombosed areas and provides structural information on thrombi and the attachment sites to the endothelium. These noninvasive methods are insensitive to thrombosis in the lower leg. Color duplex sonography in addition provides diagnostic information about the quantitative blood flow and simplifies the diagnostic procedure. If these tests are not available or the findings are equivocal, contrast venography is performed, which is the most sensitive and reliable test for confirming or excluding deep venous thrombosis.