The following tests may be done to diagnose SVCS and find the location of the blockage:
- Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
- CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography. A CT scan of the chest will be done to diagnose SVCS.
- Venography: A procedure to x-ray veins. A contrast dye is injected into the veins to outline them on the x-rays.
- MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI).
- Ultrasound: A procedure in which high-energy sound waves (ultrasound) are bounced off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram.
The type of cancer can affect the type of treatment needed; for this reason, a diagnosis of suspected cancer should be made before treatment of SVCS is begun. Unless the airway is blocked or the brain is swelling, waiting to start treatment while a diagnosis is made usually presents no problem in adults. If lung cancer is suspected, a sputum sample and a biopsy may be taken.