[Ultrasonics and deep vein thrombosis. Ilio-caval level and the lower extremities].

All the important abdominal veins and limbs vein can be examined. The veins, in cross-section are rounded in repletion, (maximum normal vein caliber has reached when erect) almost flat in a state of vacuous-ness. The lumen normally echofree is limited by a wall thinner and less echogenic than the wall of adjacent artery. The parietal motions are rythmed by breathing. Venous blood flow can become echogenic, with weak echoes, as snow storm within the lumen. These phenomena are often visible in venous confluent and within the lumen below occlusion where there is sludge. In supine position deep abdominal veins, limbs veins until popliteal veins are easily seen. Below the popliteal fossa in prone position the veins are nearly empty and not visible beyond pathological circumstances. Objective studies demonstrated the inaccuracy of clinical diagnosis of deep venous thrombosis, echotomography (coupled with doppler) is among the non-invasive methods the most interesting, permitting to recognize venous occlusion complete or incomplete by clot but also compression by tumour or ganglion. The compression under the probe collapse the normal vein, but if there is clot inside, the compression become incomplete or impossible. The caliber of the vein is dilated also in supine position. The richest of venous clot in red cells in comparison with arterial thrombus make it more and earlier echogenic and more especially as the investigation is performed with high frequency probe. In the same way if the clot is floating its motions are put in evidence. Echotomography make usually difference between clot and neoplastic thrombus which is again more echogenic and also have special location. Echotomography permit to follow evolution ot venous thrombosis under treatment. The wall vein lesions after thrombosis are analysed showing thickening, destruction of the cups, dilatation of some veins while others are still obstructed.