CT angiography combines a CT scan with the injection of dye. This technique is able to create pictures of the blood vessels in the arms or legs. CT stands for computed tomography.
You will lie on a narrow table that slides into the center of the CT scanner.
When you are inside the scanner, the machine's x-ray beam rotates around you. Modern "spiral" scanners can perform the exam without stopping.
A computer makes multiple images of the body area, called slices. These images can be stored, viewed on a monitor, or printed on film. Models of the body area in three-dimension can be created by adding the slices together.
You must stay still during the exam, because movement blurs the pictures. You may have to hold your breath for short periods of time.
The scan should take only about 5 minutes.
Some exams require a special dye, called contrast, to be injected into your body before the test. Contrast helps certain areas show up better on the x-rays.
The contrast can worsen kidney function problems in people with poorly functioning kidneys. Talk to your provider if you have a history of kidney problems.
Too much weight can cause damage to the scanner's working parts. If you weigh more than 300 pounds (135 kilograms), talk to your doctor about the weight limit before the test.
You will need to remove jewelry and wear a hospital gown during the CT exam.
Some people may be uncomfortable lying on the hard table.
Contrast given through an IV may cause a:
These feelings are normal and usually go away within a few seconds.
You may need this test if you have symptoms of a narrowed or blocked blood vessel in the arms, hands, legs, or feet.
The test may also be done to diagnose:
Results are considered normal if no problems are seen.
An abnormal result is commonly due to narrowing and hardening of the arteries in the arms or legs from plaque buildup in the artery walls.
The x-ray may show a blockage in the vessels caused by:
Abnormal results may also be due to:
Risks of CT scans include:
CT scans give off more radiation than regular x-rays. Having many x-rays or CT scans over time may increase your risk for cancer. However, the risk from any one scan is small. You and your provider should discuss this risk compared with the value of an accurate diagnosis for the problem. Most modern scanners use techniques to use less radiation.
Let your provider know if you have ever had an allergic reaction to injected contrast dye.
Rarely, the dye may cause a serious allergic response called anaphylaxis. This can be life-threatening. Notify the scanner operator right away if you have any trouble breathing during the test. Scanners have an intercom and speakers so the operator can hear you at all times.
Reviewed By: Deepak Sudheendra, MD, FSIR, RPVI, Assistant Professor of Interventional Radiology & Surgery at the University of Pennsylvania Perelman School of Medicine, with an expertise in Vascular Interventional Radiology & Surgical Critical Care, Philadelphia, PA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.