The superior vena cava syndrome caused by malignant disease. Imaging with multi-detector row CT.

OBJECTIVE: The superior vena cava (SVC) obstruction by malignant diseases is either by direct invasion and compression or by tumour thrombus of the SVC. Whatever is its cause, obstruction of the SVC causes elevated pressure in the veins draining into the SVC and increased or reversed blood flow through collateral vessels. Severity of the syndrome depends on the collateral vascular system development. Therefore, imaging of the collateral veins with variable location and connection is important in determining the extension and management of the disease. Our aims are to describe collateral vessels of the superior vena cava syndrome (SVCS) related with the malignant diseases and to assess the ability of multi-detector row CT with multiplanar and 3D volume rendering techniques in determining and describing collateral circulations.

MATERIALS AND METHODS: We present CT angiography findings of seven patients with small cell carcinoma of the lung (n = 2), squamous cell carcinoma of the lung (n = 3), Hodgkin disease of the thorax (n = 1), and squamous cell carcinoma of the oesophagus (n = 1). The patients received contrast-enhanced CT scans of the chest and abdomen on a multi-detector row CT during breath holding at suspended inspiration.

RESULTS: CT images revealed the cause and level of the SVC obstruction in all patients with axial and multiplanar reconstructed images. The SVC showed total obstruction in five patients and partial obstruction in two patients. The most common experienced collateral vessels were azygos vein (6), intercostal veins (6), mediastinal veins (6), paravertebral veins (5), hemiazygos vein (5), thoracoepigastric vein (5), internal mammary vein (5), thoracoacromioclavicular venous plexus (5), and anterior chest wall veins (5). While one case showed the portal-systemic shunt, V. cordis media and sinus coronarius with phrenic veins were enlarged in two cases, and the left adrenal vein was enlarged in a patient. In one case, the azygos vein with reversed blood flow was drained into both inferior vena cava and hemiazygos vein with the left renal vein.

CONCLUSION: Multi-detector row CT with multiplanar and 3D imaging is an effective tool in evaluation of the SVCS and has a greater advantage than the other imaging techniques. 3D volume rendering is a useful technique in determining and describing collateral circulations in addition to the primary disease process.