Role of CT Venography in the Diagnosis and Treatment of Benign Thoracic Central Venous Obstruction

OBJECTIVE: To evaluate the role of CT venography in the diagnosis and treatment of benign thoracic central venous obstruction. MATERIALS AND METHODS: Eighteen patients who had undergone both CT venography and digital subtraction venography were prospectively enrolled in this study. The following features were analyzed by two observers: the cause, degree, and extent of venous obstruction; associated thrombosis; and implications for the planning of treatment. CT venography and digital subtraction venography were compared in defined venous segments, and the degree of obstruction, and correlation was expressed using Spearman's rank correlation coefficient. RESULTS: In all patients, CT venography depicted the causes of obstruction, including extrinsic compression of the left brachiocephalic vein, and mediastinal inflammatory pseudotumor. Interobserver agreement regarding classification of the degree of obstruction was judged as good for CT venography (k=0.864), and in evaluating this, there was significant correlation between CT venography and digital subtraction venography (reader 1: Rs = 0.58, p < 0.01; reader 2: Rs = 0.56, p < 0.01). In evaluating the status of central veins proximal to long segmental obstruction, and associated thrombosis, CT venography was superior to digital subtraction venography. In half of all patients, the findings of CT venography led to changes in the treatment plan. CONCLUSION: The findings of CT venography correlated closely with those of digital subtraction venography, and the former accurately depicted the degree and extent of benign venous obstruction.

"Aorta-in-Aorta" Sign on Chest Radiograph Representing Enlarged Left Superior Intercostal and Hemiazygos Veins

We recently encountered a patient with membranous obstruction of the inferior vena cava in whom the left superior intercostal and hemiazygos veins were dilated. At chest radiography, the dilation simulated the presence of a second aortic knob and descending thoracic aorta lateral to the originals, and an "aorta-in-aorta" appearance was thus created.

Right to Left Shunt as a Collateral Circulation in a Patient with Superior Vena Cava Syndrome: A Case Report

In patients with superior vena cava syndrome, the form of the collateral circulatory system whichcommuni-cates with the inferior vena cava via various systemic veins usually varics. We found an instance ofunusual collateral circulation : direct communication between the systemic and pulmonary vein in a woman withsuperior vena cava syndrome caused by metastatic lymph node enlargement. In this report, we describe the CT andradionuclide venographic findings.

The Significance of Collateral Vessels, as Seen on Chest CT, in Predicting SVC Obstruction

PURPOSE: To evaluate the significance of collateral veins, as seen on chest CT, in the diagnosis of superiorvena cava obstruction. MATERIAL AND METHOD: We retrospectively reviewed the records of 81 patients in whomcollateral veins were seen on chest CT. On spiral CT(n=49), Contrast material was infused via power injector, andon conventional CT(n=32), 50ml bolus infusion was followed by 50ml drip infusion. Obstruction of the SVC wasevaluated on chest CT ; if, however, evaluation of the SVC or its major tributaries was difficult, as in fivecases, the patient underwent SVC phlebography. Collateral vessels were assigned to one of ten categories. RESULT: On conventional CT, the common collaterals showing statistically significant difference between the two groupswere the jugular venous arch in the group with venous obstruction(n=6/15, 40.0%), and around the back and scapula(n=15/17, 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=9/14, 64.3%; n=26/35, 74.3%, respectively) andthe paravertebral system (n=9/14, 64.3%, n=22/35, 62.9%, respectively) in both groups, with or without venousobstruction. No collateral showed a statistically significant difference between the two groups. CONCLUSION: Onconventional 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.

Percutaneous Insertion of Inferior Vena Cava Filter: Clinical Results of 8 patients

PURPOSE: To evaluate the efficacy and clinical results of percutaneous insertion of inferior vena cava(IVC) filter. MATERIALS AND METHODS: Over a two year period, eight IVC filters were placed in eight patients with pulmonary thromboembolism resulting from deep vein thrombosis of the legs. The indications for placement were contraindication to anticoagulation(3), and recurrent pulmonary embolism during anticoagulant therapy(5). Both femoral(7) and jugular(1) routes were used for percutaneous transvenous insertion. To delineate the caval anatomy and to ensure placement just caudal to the renal vein, a cavogram was obtained before filter placement. Bird's Nest (7) and Greenfield (1) filters were inserted. Follow-up information was obtained by means of duplex sonography, CT scan, abdominal radiograph, and perfusion scan of the lungs, followed by clinical evaluation. RESULTS: In all cases, procedures were technically successful. Placement complications occurred in three patients. In one, the filter was inadvertently placed above the iliac bifurcation; in the other two, prolapse of the Bird's Nest filter wire occurred. Occlusion of IVC occurred in two patients, and recurrent pulmonary embolism was suspected in one, who suffered from chest pain and shortness of breath. In the other patients, there was no clinical evidence of recurrence of the pulmonary embolism. CONCLUSION: Insertion of an inferior vena cava filteris a safe and effective method for the prevention of pulmonary embolism when anticoagulant therapy is either ineffective or contraindicated.