Intravascular ultrasonography. Normal and pathologic findings in the great veins.

The intravascular ultrasonographic findings in normal and diseased veins after transfemoral catheterization of 25 patients are presented. The iliac veins, the inferior and superior vena cava, the renal veins, the right atrium, both brachiocephalic veins, and the right internal jugular vein were studied. In 4 cases valves or valve-like structures were observed. Anatomic variants such as spurs and webs were seen in 3 and mural thrombi or postthrombotic wall changes in 4 patients. In one case a sphincter-like ostium venae cavae was observed. In 2 patients thin filaments within the right atrium, most likely a Chiari net, were seen. Two patients had an abnormal, stratified "artery-like" vessel wall structure. This new imaging modality has several potential applicabilities in the veins and may contribute new information about anatomy and function of the venous system. It provides cross-sectional in vivo visualization and the demonstration of motility of small intraluminal structures which cannot be revealed by traditional diagnostic methods. Because of the wide range of anatomic variation in the venous system, knowledge of its normal intravascular ultrasonographic appearance is a prerequisite for further clinical investigations.