[The diagnosis of deep venous thrombosis of the lower extremities using high-resolution real-time and CW-Doppler sonography. Accuracy and limitations]

The combination of high-resolution real time and continuous wave (CW) Doppler sonography is particularly valuable for the detection of venous thrombosis in the lower limbs. A total of 235 venous sonograms were prospectively compared with phlebography (gold standard) and indicated a sensitivity and specificity of 93%-100% and 96%-99%, respectively, depending on the thrombosis site. The positive and negative predictive values ranged between 90% and 97% and 97% and 100%, respectively. The value of real-time venous sonography, which basically entails assessing venous compressibility for the exclusion of thrombosis, is limited in the presence of small non-occlusive thrombi by the elasticity of the surrounding anatomic structures and the sonographic visibility of the veins. It is also evident that partial thrombosis in readily visualized veins (e.g., the inguinal region) is more obvious with sonography than phlebography. In addition, the proximal end of acute, extensive thrombus with poor collateral circulation is better visualized by sonography.