We've all heard of people who appeared to be healthy dropping dead of a heart attack in their 50s or 60s. They had no idea they had heart disease. A new test can reveal a heart attack waiting to happen.

A coronary calcium scan is a CT scan that measures the amount of plaque building up in the arteries and whether there is a risk of heart attack.

"I really have been promoting it to all my patients, all my friends and family, because you just can't look at someone -- even though we check your blood pressure, check your cholesterol, some people have great numbers and still have a high calcium score," said Mercy Medical Center Dr. Jeffrey Landsman.

Landsman recommends the coronary calcium scan for patients in their mid-40s and older, particularly those with a family history of heart disease, such as Jane Wilson.

"They found that I have the beginning of heart disease,' Wilson said.

It was a wake-up call.

"Inspired me to lose weight. I lost 50 pounds and I've become much more diligent about walking. I walk a mile and a half every day. I like to be outside, so I do that. I wasn't doing that before, either. So, it did change my behavior," Wilson said.

Landsman said calcium buildup is not reversible. The benefit of the test is patients have the opportunity to keep keeping it from getting worse.

"Give you time to make lifestyle changes, medications to prevent progression if you are developing early heart disease," Landsman said.

When Wilson had a follow-up scan done, her score was about the same. That's good news to her.

"I'm glad that I changed my behavior and it's not getting worse, so that is good news. That's a good result," Wilson said.