What Is a Coronary Calcium Scan?

A coronary calcium scan is a test that can help show whether you have coronary heart disease (CHD), also called coronary artery disease. CHD is the most common type of heart disease in both men and women.

In CHD, a substance called plaque (plak) builds up inside your coronary arteries. These arteries supply your heart muscle with oxygen-rich blood. Plaque is made up of fat, cholesterol, calcium, and other substances found in the blood.

Plaque narrows your coronary arteries and reduces blood flow to your heart muscle. It also makes it more likely that blood clots will form in your coronary arteries. Blood clots can partly or completely block blood flow to part of your heart muscle. This can cause chest pain or discomfort called angina (an-JI-nuh or AN-juh-nuh) or a heart attack.

CHD also can lead to heart failure or arrhythmias (ah-RITH-me-ahs). Heart failure is a condition in which your heart can't pump enough blood to meet your body's needs. Arrhythmias are problems with the rate or rhythm of your heartbeat.

Overview

A coronary calcium scan looks for specks of calcium (called calcifications) in the walls of the coronary arteries. Calcifications are an early sign of CHD. The test can show whether you're at increased risk for a heart attack or other heart problems before other signs and symptoms occur.

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. The scanner takes pictures of the heart that show whether the coronary arteries have calcifications.

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, which shows calcification in a coronary artery.

Outlook

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 who are at moderate risk have a 10–20 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.

Revised November 2009