What Is a Coronary Calcium Scan?
A coronary calcium scan is a test that can help show
whether you have
coronary
artery disease (CAD). In CAD, a fatty material called plaque (plak) narrows
your coronary (heart) arteries and limits blood flow to your heart. CAD is the
most common type of heart disease in both men and women. It can lead to
angina,
heart
attack,
heart
failure, and
arrhythmia.
Coronary calcium scanning looks for specks of
calcium (called calcifications) in the walls of the coronary arteries.
Calcifications are an early sign of heart disease. The test can show, before
other signs and symptoms occur, whether you’re at increased risk for a
heart attack or other heart problems.
A coronary calcium scan is most useful for people
who are at moderate risk for a heart attack. You or your doctor can calculate
your 10-year risk using the
Risk
Assessment Tool from the National Cholesterol Education Program. People at
moderate risk have a 10 to 20 percent chance of having a heart attack within
the next 10 years. The coronary calcium scan may help doctors decide who within
this group needs treatment.
Two machines can show calcium in the coronary
arteries—electron beam computed tomography (EBCT) and multidetector
computed tomography (MDCT). Both use an x-ray machine to make detailed pictures
of your heart. Doctors study the pictures to see whether you’re at risk
for heart problems in the next 2 to 10 years.
A coronary calcium scan is simple and easy for the
patient, who lies quietly in the scanner machine for about 10 minutes. Pictures
of the heart are taken that show whether the coronary arteries have
calcifications. (For more information, see “ What To Expect During a Coronary Calcium
Scan.”)
Coronary Calcium
Scan
Figure A shows the position of the
heart in the body and the location and angle of the coronary calcium scan
image. Figure B is the coronary calcium scan image showing calcification in a
coronary artery.
Other Names for Coronary Calcium Scans
- Calcium scan test
- Cardiac CT for calcium scoring
Sometimes people refer to a coronary calcium scan by
the name of the machine used to take pictures of the heart:
- Electron-beam computed tomography (EBCT) or
electron-beam tomography (EBT)
- Multidetector computed tomography (MDCT)
What To Expect Before a Coronary Calcium Scans
No special preparation is needed. You may be asked
to avoid caffeine and smoking for 4 hours before the test. For the scan, you
will remove your clothes above the waist and wear a hospital gown. You also
will remove any jewelry from around your neck or chest.
What To Expect During a Coronary Calcium Scan
Coronary calcium scans are done in a hospital or
outpatient office. The x-ray machine that’s used is called a computed
tomography (CT) scanner.
The technician who operates the scanner will clean
areas of your chest and apply small sticky patches called electrodes. The
electrodes are attached to an
EKG
(electrocardiogram) monitor. The EKG measures the electrical activity of your
heart during the scan. This makes it possible to take pictures of your heart
when it’s relaxed, between beats.
The CT scanner is a large machine that has a hollow,
circular tube in the center. You will lie on your back on a sliding table. The
table can move up and down and goes inside the tunnel-like machine.
The table will slowly slide into the opening in the
machine. Inside the scanner, an x-ray tube moves around your body to take
pictures of your heart. You may be asked to hold your breath for 10 to 20
seconds while the pictures are taken. This prevents movement in the image.
During the test, the technician will be in a nearby
room with the computer that controls the CT scanner. The technician can see you
through a window and talk to you through an intercom system.
You may be given medicine to slow down a fast heart
rate. This helps the machine take better pictures of your heart. The medicine
will be given by mouth or injected into a vein.
A coronary calcium scan takes about 5 to 10 minutes.
During the test, the machine makes clicking and whirring sounds as it takes
pictures. It causes no discomfort, but the exam room may be chilly to keep the
machine working properly.
If you become nervous in enclosed spaces, you may
need to take medicine to stay calm. This isn’t a problem for most people,
because your head will remain outside the opening in the machine.
What To Expect After a Coronary Calcium Scan
You’re able to return to your normal
activities after the coronary calcium scan is done. A doctor who is trained in
reading these scans will discuss the results with you.
What Does the Coronary Calcium Scan Show?
After the coronary calcium scan, you will get a
calcium score called an Agatston score. The score is based on the amount of
calcium found in your coronary arteries. You may get an Agatston score for each
major artery and a total score.
The test is negative if no sign of calcium deposits
(calcifications) is found in your arteries. This means your chance of having a
heart
attack in the next 2 to 5 years is low.
The test is positive if calcifications are found in
your arteries. Calcifications are a sign of
atherosclerosis
(ATH-er-o-skler-O-sis) and
coronary
artery disease. (Atherosclerosis is when the arteries harden and narrow due
to plaque buildup.) The higher your Agatston score, the greater the amount of
atherosclerosis.
Use this
calculator (from the National Heart, Lung, and Blood
Institute) to see whether your score is high. If it is, your doctor may
prescribe medicines or order more tests.
What Are the Risks of a Coronary Calcium Scan?
Coronary calcium scanning has very few risks. The
test isn’t invasive, which means that no surgery is done and no
instruments are inserted into your body. Coronary calcium scanning
doesn’t require an injection of contrast dye to make your heart or
arteries visible on the x-ray images.
Because an x-ray machine is involved, you will be
exposed to a small amount of radiation. Electron-beam computed tomography
(EBCT) uses less radiation than multidetector computed tomography (MDCT). In
either case, the amount of radiation is less than or equal to the amount of
radiation you’re naturally exposed to in a single year.
Key Points
- A coronary calcium scan is a test that can help
show whether you have
coronary
artery disease (CAD).
- Coronary calcium scanning looks for specks of
calcium (called calcifications) in the walls of the coronary arteries.
Calcifications are an early sign of heart disease.
- This test is most useful for people who are at
moderate risk for a
heart
attack. You or your doctor can calculate your 10-year risk using the
Risk
Assessment Tool from the National Cholesterol Education Program. People at
moderate risk have a 10 to 20 percent chance of having a heart attack within
the next 10 years.
- The coronary calcium scan may help doctors decide
who within the moderate risk group needs treatment.
- No special preparation is needed before a
coronary calcium scan.
- Coronary calcium scans are done in a hospital or
outpatient office. The x-ray machine that’s used is called a computed
tomography (CT) scanner.
- A coronary calcium scan takes about 5 to 10
minutes. During the scan, you will lie quietly on your back, while the CT
scanner takes pictures of your heart.
- You’re able to return to your normal
activities after the scan is done.
- The test is negative if there are no
calcifications in your coronary arteries. This means your chance of having a
heart attack in the next 2 to 5 years is low.
- The test is positive if calcifications are found
in your coronary arteries. Calcifications are a sign of
atherosclerosis
and CAD.
- After the scan, you will receive a calcium score
called an Agatston score. The higher the score, the greater the amount of
atherosclerosis or plaque buildup.
- Use this
calculator (from the
National Heart, Lung, and Blood Institute) to see whether your Agatston score
is high.
- Coronary calcium scanning has very few risks. The
test usually isn’t invasive, which means that no surgery is done and no
instruments are inserted into your body. Coronary calcium scan doesn’t
require the injection of contrast dye to make your heart or arteries visible on
the x-ray images. If you need medicine to slow down your heartbeat during the
scan, it may be injected into a vein.
- Because an x-ray machine is involved, you will be
exposed to a small amount of radiation. The amount of radiation is less than or
equal to the amount of radiation you’re naturally exposed to in a single
year.
Links to Other Information About Coronary Calcium
Scan
NHLBI Resources
Non-NHLBI Resources
Clinical Trials
|
DCI Home:
Heart & Vascular Diseases:
Coronary Calcium Scan: Printer Friendly Summary
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