[The ultrasound appearances of thrombosis of the inferior vena cava due to renal tumours (author's transl)].

The findings of ultra-sound in four cases of thrombosis of the inferior vena cava due to malignant renal tumours are described. In three patients the cava was occluded by tumour, twice by infiltration and once by a mobile tumour mass in the vessel. The advantages of rapid imaging of normal and abnormal vascular structures are described. The method can demonstrate the occluding material in the vessel as well as showing the extent of local tumour infiltration around the cava, information which cannot be provided by cavography in the presence of complete occlusion.