Purpose: To evaluate the significance of collateral veins, as seen on chest CT, in the diagnosis of superior vena cava obstruction.Materials and Methods: We tetrospectively reviewed the records of 81 patients in whom collateral veins were seen on chest CT. On spiral CT(n=49), Contrast material was infused via power injector, and on conventional CT(n=32), 50ml bolus infusion was followed by 50ml drip infusion. Obstruction of the SVC was evaluated on chest CT; if, however, evaluation of the SVC or its major tributaries was difficult, as in five cases, the patient underwent SVC phlebography. Collateral vessels were assigned to one of ten categories.Results: On conventional CT, the common collaterals showing statistically significant difference between the two groups were the jugular venous arch in the group with venous obstruction (n=6 /1 5, 40.0%), and around the back and scapula (n=15 /1 7, 88.2%) and paravertebral system (n=12/17, 70.6%) in the group without venous obstruction.On helical CT, the most common collaterals were around the back and scapular (n=9 /1 4, 64.3%; n=26/35, 74.3%, respectively) and the paravertebral system (n=9 /1 4, 64.3 %, n=22/35, 62.9% , respectively) in both groups, with or without venous obstruction. No collateral showed a statistically significant difference between the two groups.Conclusion : On conventional CT, the jugular venous arch is the only collateral vessel to predict SVC obstruction; on spiral CT, however, collateral vessels are not helpful in the diagnosis of SVC obstruction, but are a nonspecific finding.Index words: Thorax, CT Veins, CT Venae cavae, CT Venae cavae, stenosis or obstruction Address reprint requests to : Yong
