This test is done in the hospital. You will lie on an x-ray table.
The health care provider will clean and shave the area of the body (usually near the groin) and apply numbing medicine to the area. A needle is placed into to the artery.
Once the needle is in the proper position, a thin wire passes through it. The needle is taken out, and a long, narrow, flexible tube called a catheter is put in its place. An instrument called a fluoroscope sends x-ray images of the body to a TV monitor. The images help the radiologist guide the catheter into the right position. The catheter runs over the wire and is pushed up through the main blood vessels of the pelvis into the aorta (the main blood vessel running down from the heart to the lower body).
The test uses a special dye (called "contrast medium") to help the arteries show up better on the x-ray. The blood vessels of the kidneys cannot be seen with ordinary x-rays. The dye flows through the catheter into the kidney artery.
X-ray images are taken as the dye moves through the blood vessels. Saline (sterile salt water) containing a blood thinner may also be sent through the catheter to keep blood in the area from clotting.
A computer may be used to "subtract" out the bones and tissues in the area so that only the blood vessels filled with the dye can be seen. This is called digital subtraction angiography (DSI).
The catheter is removed after the x-rays are taken. Pressure is immediately applied to the area for 10 to 15 minutes or more to stop the bleeding. After that time, the area is checked and a bandage is applied. You should keep your leg straight for 6 hours after the procedure.