Venography(Phlebography) No evidence of intraluminal filling defects, obstruction, incompetent venous valves, calcifications, or dilatations of collateral veins To investigate venous function , suspected obstruction, venous insufficiency, and the source of Pulmonary Embolism To evaluate veins before and after bypass surgery, reconstructive surgery, or thrombotic therapy to determine the effectiveness of treatment Deep Vein Thrombosis Tumor (extrinsic compression) Vascular tumor (intrinsic blockage) Venous compression syndrome Venous insufficiency Varicose Veins Congenital malformation Traumatic injury to the vein Allergy to iodide or contrast medium Renal failure Congestive Heart Failure Severe pulmonary hypertension