How can an angiography help diagnose colorectal cancer?

Angiography is an x-ray procedure for looking at blood vessels. Contrast medium, or dye, is injected into an artery before x-ray images are taken. The dye outlines the blood vessels on x-ray pictures.

Angiography can be useful in showing the arteries that supply blood to tumors in the liver. This can help surgeons decide whether a cancer can be removed and if so, it can help in planning the operation.

Angiography can be uncomfortable because the doctor who does the procedure has to put a small catheter (a flexible hollow tube) into the artery leading to the liver to inject the dye. Usually the catheter is put into an artery in your inner thigh and threaded up into the liver artery. A local anesthetic is often used to numb the area before inserting the catheter. Then the dye is injected quickly to outline all the vessels while the x-rays are being taken.

Angiography may also be done with a CT scanner (CT angiography) or an MRI scanner (MR angiography). These techniques give information about the blood vessels in the liver without the need for a catheter, although you may still need an IV line so that a contrast dye can be injected into the bloodstream during the imaging.