Venous renal tumor extension: a prospective US evaluation.

To evaluate the ability of ultrasonography (US) to determine venous tumor extension, we studied 120 consecutive patients with renal neoplasms. The incidence of renal vein involvement in this group was 18%; caval tumor extension occurred in 11% of the patients. Real-time US clearly visualized the entire retrohepatic inferior vena cava (IVC) in 96% of the examinations, and the ipsilateral renal vein was well seen on 88% of the scans. Of the caval sonograms that could be evaluated (115/120), intravascular tumor thrombi were detected in all 13 cases (sensitivity and specificity = 100%). Of the assessable sonograms of the renal vein (105/120), tumor invasion was identified by US in 21 of 22 cases (sensitivity = 95.5%, specificity = 100%). Venous tumor involvement was seen with intravascular lesions of different echogenicity, which caused a neoplastic-induced renal or caval vein enlargement in most cases. Our findings show that US is of great value in the preoperative assessment of intravascular tumor extension and provides a useful alternative to inferior venacavography.