The patient

A 59 year old woman with a history of recurrent left sided breast cancer presented in October 2004 with bilateral arm and neck swelling, increasing shortness of breath, and headaches. We made a working diagnosis of obstruction of the superior vena cava. She had undergone surgery and external beam radiotherapy 13 years before for primary breast cancer. She subsequently underwent left mastectomy and chemotherapy for reoccurrence in 2000.

What is the next investigation?

Superior vena cava obstruction is usually diagnosed clinically, with the patient presenting with signs and symptoms related to venous congestion (box 1). Chest radiography usually demonstrates the abnormality with a widened mediastinum, although this may be normal.1

Contrast enhanced computed tomography is the most commonly performed diagnostic imaging test. With multiplanar reformatting, this test allows accurate diagnosis and can show the extent, level, and cause of superior vena cava obstruction. The presence of dilated collateral vessels is highly suggestive of superior vena cava obstruction, with a sensitivity of 96% and specificity of 92%.5 6 7 Before the widespread use of computed tomography, upper limb venography was used to determine the level and extent of superior vena cava obstruction. However, it does not identify the cause of the obstruction and can overestimate the extent of venous occlusion as a result of shunting of blood through collaterals. Magnetic resonance venography is an alternative investigation that is increasingly being used. It has 100% sensitivity, …