What is a Heart CT Scan?

Your doctor will order a coronary calcium scan - also called a "heart" or "cardiac" CT scan - to help determine your level of risk for heart disease and heart attack. Using computed tomography, a blend of X-ray technology and computer processing, the scan is used to look for, and measure, calcified plaque in the arteries of the heart. Calcium deposits in the coronary arteries are strong indicators of cardiac problems, and the early detection of cardiovascular disease and its risk factors can be a potential lifesaver.

The Benefits and Risks of a Heart CT Scan

Coronary Calcium Scan Risks

Nurse during a Heart CT Scan

Since computed tomography is partially comprised of X-ray technology, it employs ionizing radiation. The amount, however, is relatively small and does not put your long-term health in jeopardy. In addition, imaging technicians minimize the amount of radiation used by employing the following measures:

  • Justification: Doctors limit radiation exposure by only ordering coronary CT scans when patients meet certain guidelines. These include risk factors for heart disease or heart attack.
  • Optimization: This is the practice of using the smallest dose of radiation possible to complete the task.

Cardiac CT Scan Side Effects

During some coronary calcium scans, a contrast dye is used to highlight the arteries, veins or other parts of the heart. In rare cases, a patient may be allergic to this dye. When reactions do occur, the side effects are minor - generally including mild hives and itching - and pose no danger to the patient.

The benefits of a cardiac CT scan, in fact, far outweigh the possible side effects, especially when the risk of coronary disease or heart attack is present.

What You Should Know Before a Cardiac CT Scan

In preparation for a cardiac CT scan, you will need to:

  • Avoid caffeine and nicotine on the day of the test. Fasting is not required.
  • Wear loose clothing and remove anything made from metal - especially jewelry.
  • Let the doctors and technicians know if you're currently undergoing radiation therapy, or if you are, or may become, pregnant.
  • Discuss any potential complications from claustrophobia (fear of enclosed spaces).

What to Expect During a Cardiac CT Scan

Monitors during a Heart CT ScanWhen you arrive for your cardiac CT scan, you will first change into a hospital gown and have your vitals taken. You will then be guided through the following:

  • The imaging technician will ask you to lie down on a scanning table.
  • Your chest will be cleaned with an antibacterial wipe (and in some cases chest hair will be shaved) before electrodes are applied.
  • The imaging technician will then insert an IV into your arm, which is used to administer the contrast dye, if necessary.
  • When you're ready, the imaging technician will move the table inside the doughnut-shaped CT machine and begin the scanning process, which usually takes 15 minutes or less.
  • The electrodes applied to your chest will be attached to an electrocardiagram, or EKG, which will record your cardiac activity and coordinate the timing of the X-ray imaging, and the CT scanner will use computer processing to create a 360-degree, 3D image of the heart.

Cardiac CT Scan Results

After the scan, a cardiovascular radiologist will analyze your results. A report will be delivered to your doctor, who will schedule an appointment to meet and explain the results of your scan in person. Calcium scores are interpreted in the following way:

  • 0-10: Zero is the most desirable score because it indicates no existence of calcified plaque in the coronary arteries. In this case, the chance of heart attack or disease in the next two to five years is less than 5%. A score higher than zero, but less than 10, means a small amount of calcification was found, and a doctor will typically recommend lifestyle changes to reduce your risk for heart disease.
  • 11-100: Scores in this range signal mild hardening of the arteries. Some plaque is present, and the risk of heart attack is mild to moderate.
  • 101-400: If your score falls in this range, you are considered to have moderate plaque, with the possibility of plaque blocking an artery. Your heart attack risk is moderate to high, and more testing is likely to be recommended.
  • Over 400: If your score is over 400, it means extensive plaque was found, placing your chance of coronary artery blockage at over 90%. If you are in this range, you are at a high risk of heart attack.

Who Should Have a Cardiac CT Scan?

A cardiac CT scan is not for those with known heart disease. But some patients have passed stress tests and EKGs, only to discover early signs of heart disease or heart attack vulnerability through a cardiac CT scan. The test is able to find calcified plaque well before signs of illness appear, and many doctors use it as a starting point for further, more invasive testing or treatment.

You should ask your doctor about this potentially life-saving procedure if you are between the ages of 40 and 70, and have one of more of the following risk factors:

Memorial Hermann provides coronary calcium scans at many locations in the Greater Houston area. If your doctor has ordered a cardiac CT scan, you can count on one of the region's most trusted health systems by choosing the Memorial Hermann location near you.

Other Types of Heart Exams

Stress Test

Stethoscope and chart for a Stress TestTo help diagnose certain health problems, a stress test is performed. During a stress test a patient will exercise, usually on a treadmill or stationary bike. During the exercise, tests are performed on the heart to find or determine the severity of coronary artery disease.

If a patient is unable to undergo strenuous exercise, the doctor may use medicine to mimic the effects of a workout by making the heart work harder. While this test can be effective in diagnosing some types of cardiac disease, coronary calcium scans often find evidence of disease before it becomes a health threat.

Electrocardiogram (EKG)

An EKG, sometimes known as an ECG, is a fast, portable method for monitoring heart activity and detecting cardiac problems. This noninvasive option, however, does not show the calcium deposits that can signal the early stages of heart disease.

Coronary Angiogram

A coronary angiogram is a type of X-ray imaging that provides a look at the blood vessels of the heart when symptoms of a heart problem occur, or after a stress test shows potential abnormalities. Doctors may also open clogged arteries during the procedure. This type of cardiac catheterization is usually only performed when noninvasive resources have been exhausted. In contrast, cardiac CT scans are noninvasive, provide results in the earliest stages of disease and carry fewer risk factors.

Why Choose Memorial Hermann for Your Cardiac CT Scan?

The affiliated radiologists at Memorial Hermann ensure a high level of accuracy in heart CT scans for our patients, and our hospitals are equipped with advanced, cutting-edge technology.

Schedule your Cardiac CT scan appointment at a convenient Memorial Hermann location near you by calling (877) 704-8700.