Venography (also called phlebography or ascending phlebography) allows visualization of the veins of the brain, head, neck or spine.
Venography can be performed one of two ways. A catheter can be inserted into a large artery (such as the femoral, brachial, or radial artery) and threaded through the circulatory system to the carotid, vertebral, subclavian artery, or segmental arteries, where a contrast agent (dye) is injected. A series of radiographs (x-rays) are taken as the contrast agent spreads through the venous systems (see images below). Alternatively, a catheter can be placed directly into one of the veins of the brain or neck and a contrast agent can be injected as radiographs are taken.
Venography can be used to distinguish blood clots in the veins from obstructions, can be used to evaluate congenital vein problems, and can be used to measure pressure differences across areas of narrowing.
