PRINCIPLES OF TECHNICAL DIAGNOSIS OF DEEP VENOUS THROMBOSIS

The bedside diagnosis of deep venous thrombosis is not accurate enough to implement invasive therapy, e. g., systemic administration of thro mbolytic agents, so the diagnosis must be established by independent d iagnostic means. The most useful diagnostic tests available include Do ppler ultrasound, duplex sonography, color duplex sonography, and cont rast venography. The common femoral vein and popliteal vein can be exa mined easily with a Doppler ultrasound probe. Reduced blood flow due t o major venous thrombosis proximal or distal to the probe, qualitative blood flow and flow direction are all detectable. Duplex sonography a llows imaging of thrombosed areas and provides structural information on thrombi and the attachment sites to the endothelium. These noninvas ive methods are insensitive to thrombosis in the lower leg. Color dupl ex sonography in addition provides diagnostic information about the qu antitative blood flow and simplifies the diagnostic procedure. If thes e tests are not available or the findings are equivocal, contrast veno graphy is performed, which is the most sensitive and reliable test for confirming or excluding deep venous thrombosis.