Sonographic diagnosis of subclavian and internal jugular vein thrombosis.

Seven patients with internal jugular and/or subclavian vein thrombosis were studied with real-time sonography and venography. High-resolution real-time sonography was used to tabulate morphologic parameters (venous size, shape, intraluminal echoes, and presence of collateral veins), as well as physiologic parameters (mobile venous valves, distention, compressibility, pulsation). Chronic venous thrombosis was characterized by the presence of collateral veins, spread of the thrombus to other major veins, and loss of normal vascular landmarks with poor visualization of the actual thrombus, the "cut-off sign." Acute catheter-induced thrombosis was confined to one vessel, and the thrombus was seen clearly in all cases. Two new signs of thrombosis, the absence of the beating venous valve and the "cut-off sign," are particularly useful in the sonographic diagnosis of internal jugular vein thrombosis.