Value of real time B mode ultrasound imaging in the diagnosis of deep vein thrombosis of the lower limbs.

In order to determine the value and the role of real time B mode ultrasound imaging (USI) in the diagnosis of deep vein thrombosis (DVT) of the lower limbs, it was compared to bilateral contrast ascending venography used as a standard of reference, prospectively and systematically on 430 patients suspected of having DVT or pulmonary embolism. A total of 854 limbs were thus studied double blindly both by the two methods. The results corresponded in 95% of the legs with a sensitivity of 98% and a specificity of 95% for USI. Isolated thrombosis of the calf were detected in 91% of the legs and proximal thrombosis were in 100% in this series whatever their topography and extent should be and whatever be the degree of obstruction of the vein. The discrepancies between the two methods are related to: (a) Vein thrombosis especially located in the calf, in the soleal sinuses and the gastrocnemius with in most cases the direct image of the thrombus detected by U.S.I. more often than by venography, provided that the technique and the equipment are appropriate. (b) The absence of visualisation of venous segments with venography which is not specific of venous thrombosis. These veins when non affected by the thrombosis are not filled by the contrast medium if located above an occluded ilio-femoral or ilio-caval junction or when they are the site of extrinsic compression. The direct imaging of the vein and the surrounding structures obtained with USI enhances the diagnostic sensitivity and specificity and provides precision of the exact extension of the thrombosis. Venous study by USI is always coupled with the Doppler.(ABSTRACT TRUNCATED AT 250 WORDS)