Fig. 1.

(A) Left lower extremity venous duplex ultrasound demonstrating occlusive deep vein thrombus (DVT) in the external iliac vein (arrows). (B) Extensive left lower extremity occlusive DVT was noted on venography. Note the lysis catheter in the occluded superficial femoral vein (arrow) and filling of collateral muscular veins (arrowhead). (C) Venography demonstrates filling of collaterals draining into the internal iliac vein (arrow). Thrombolysis was initiated in the affected segments. (D) Pelvic venography demonstrated an abrupt change in contrast opacity at the confluence of the external iliac vein with the internal iliac vein (arrow), with the common iliac vein and inferior vena cava remaining patent (arrowheads).