A coronary artery calcium (CAC) scan measures the amount of calcium in heart’s arteries and high levels can be associated with heart disease, according to a Harvard University report.

The scan shows the presence of atherosclerosis, which can be difficult to find but is the underlying case in most heart attacks.

"The CAC results can help identify a person's possible risk for heart attack or stroke, even if that person doesn't have the obvious risk factors or symptoms," said Dr. Jorge Plutzky, director of preventive cardiology at Harvard-affiliated Brigham and Women's Hospital. "It can be a way for some people to get the necessary treatment early and hopefully head off a serious cardiac event."

Using special computed tomography, the CAC scan takes several pictures of your heart over a course of 20 to 30 seconds. Having too much plaque built up in the heart’s arteries can restrict blood to the heart muscle and increase your chance of a heart attack.

"The calcification process mainly identifies that atherosclerosis is present, but does not necessarily pinpoint areas that will rupture and cause a heart attack," said Dr. Plutzky.

The amount of calcification is scored on a scale from zero to 400 and higher. With the lower scores, you have a less likely chance of a heart attack or stroke.

Harvard provides a breakdown of the scores on their website.