Radionuclide and contrast venography following caval interruption by the Mobin-Uddin umbrella filter

Either radionuclide or contrast venography, or both, were performed in nine patients 2 months to 4 years after insertion of Mobin-Uddin caval umbrella filter for prevention of recurrent pulmonary embolism. In six patients the cava was occluded, and three major groups of collaterals were observed (central, intermediate and superficial). Large gonadal veins, which may predispose to recurrent embolism, were seen in two cases. Radionuclide venography gave a clear indication of caval patency or occlusion, and distinguished central from superficial collaterals. Identification of specific gonadal veins required contrast femoral or iliac venography.