Heart CT scan

Definition

A computed tomography (CT) scan of the heart is an imaging method that uses x-rays to create detailed pictures of the heart and its blood vessels.

Alternative Names

CAT scan - heart; Computed axial tomography scan - heart; Computed tomography scan - heart; Calcium scoring; Multi-detector CT scan - heart; Electron beam computed tomography - heart; Agaston score; Coronary calcium scan

How the Test is Performed

You will be asked to lie on a narrow table that slides into the center of the CT scanner.

A computer creates separate images of the body area, called slices.

You must be still during the exam, because movement causes blurred images. You may be told to hold your breath for short periods of time.

The entire scan should only take about 10 minutes

How to Prepare for the Test

Certain exams require a special dye, called contrast, to be delivered into the body before the test starts. Contrast helps certain areas show up better on the x-rays.

Before receiving the contrast:

If you weigh more than 300 pounds, find out if the CT machine has a weight limit. Too much weight can cause damage to the scanner's working parts.

You will be asked to remove jewelry and wear a hospital gown during the study.

How the Test will Feel

Some people may have discomfort from lying on the hard table.

Contrast given through an IV may cause a:

These sensations are normal and usually go away within a few seconds.

Why the Test is Performed

CT rapidly creates detailed pictures of the heart and its arteries. The test may diagnose or detect:

Normal Results

Results are considered normal if the heart and arteries being examined are normal in appearance.

Your "calcium score" is based on the amount of calcium found in the arteries of your heart.

What Abnormal Results Mean

Abnormal results may be due to:

If your calcium score is high:

Risks

Risks of CT scans include:

CT scans do expose you to 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 doctor should weigh this risk against the benefits of getting a correct diagnosis for a medical problem.

Some people have allergies to contrast dye. Let your doctor know if you have ever had an allergic reaction to injected contrast dye.

Rarely, the dye may cause a life-threatening allergic response called anaphylaxis. If you have any trouble breathing during the test, you should notify the scanner operator immediately. Scanners come with an intercom and speakers, so the operator can hear you at all times.

References

Taylor AJ. Cardiac computed tomography. In: Bonow, ed. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 9th ed. Philadelphia, PA: Saunders Elsevier; 2011:chapter 19.

Taylor AJ, Cerqueira M, Hodgson JM, et al. ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 Appropriate Use Criteria for Cardiac Computed Tomography: A Report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance. Circulation. 2010 Nov 23;122(21):e525-55.