In upright and supine chest radiographs, what size do we consider the azygos vein to be dilated?
More than 6mm on upright PA or >1 cm on supine radiograph.
Contrast-enhanced CT scan of the chest shows a large aneurysmal vessel above the right tracheobronchial angle mildly compressing and draining into the superior vena cava (T5 vertebra level). Within the aneurysm are thrombus extending to the SVC and expanding the azygocaval junction. Multifocal filling defects are noted in the right upper lobe, lingula and left lower lobe representing segmental and subsegmental pulmonary thromboembolism.