Marc Winans had a right to feel uneasy.

His maternal grandfather died of a heart attack at 55. His mother's brother made it to 57 before meeting the same fate. Several cousins on his mother's side also had heart disease - including a second cousin who died at 40.

Yet Winans did not have especially high cholesterol levels, and at 38, the Jeffersonville resident was a nonsmoker and in good physical shape.

Should he take statins as a precaution?

The answer, he hoped, lay in a big white doughnut at Temple University Hospital. Last winter, he underwent a special CT scan that would measure the calcium in his coronary arteries - an indication of hardened, calcified plaque.

Cardiologists caution that this scan is not for most people, only for those whose risk of heart disease is uncertain. The scan exposes the patient to a modest amount of radiation, which is better to avoid if there is no real benefit, and it costs from $100 to more than $300 - a sum generally not covered by insurance.

But for someone who is not a clear-cut case, such as Winans, the calcium scan can be a useful tiebreaker in the decision of whether to take statins, said Daniel Edmundowicz, Temple's chief of cardiology.

Available for years, the scan is now getting renewed attention after it was cited in new guidelines for treating cholesterol, issued in November by the American College of Cardiology and the American Heart Association. Then in March, additional support for its use came in several studies presented at the college's annual scientific session.

Winans had an LDL ("bad") cholesterol reading of 138 - not great, but common in people with a Western diet, and with his young age and otherwise good health, it was not enough to dictate a prescription for statins. The cholesterol-lowering drugs can cause muscle pain in some patients, so it would be better do without the pills if there was no need.

Yet there was the family history of heart disease. So cardiologist David Becker, who practices in Flourtown and is part of the Temple health system, told Winans the calcium scoring test could give him peace of mind.

"I just wanted to go in and be proactive," said Winans, a chef who teaches at the the International Culinary School at the Art Institute of Philadelphia.

The scan itself took just a minute or so. If he had calcified, hardened plaque in his coronary arteries - the vessels that supply oxygenated blood to the heart - it would show up as bright white on the screen.

Software also would translate the amount and density of the whiteness into a calcium "score" - a number that could range from zero to more than 400.

A week or two later, he got good news: a score of zero. No calcified plaque, so no statins for now.

Still, Winans takes pains to eat a balanced diet, and he runs and lifts weights. In two years, he will come back for another calcium scan.

The test is offered also at Thomas Jefferson University Hospital, which has scanned about 90 patients since August, and at hospitals in the Penn Medicine health system. Suburban facilities offering it include Abington Memorial, St. Mary Medical Center, and Main Line Health's Lankenau Heart Institute.

Danielle Duffy, director of cardiovascular risk reduction at the Jefferson Heart Institute, said she prescribes the scan each year for 10 to 15 patients whose cases are unclear.

She cautioned that the test does not measure soft plaque - the fatty substance more likely to lead to a heart attack. It detects only the plaque that has hardened with calcium.

The rationale behind the scan is that if you have calcified plaque, then you are likely to have soft plaque that has yet to calcify, so statins or other treatments are a good idea.

But Duffy avoids using the scan in women under 40 and men under 35, as these people may have soft plaque that has not had time to harden.

"You could get a falsely reassuring zero score," Duffy said.

Soft plaque is a killer because it can rupture, leading to a clot that blocks blood flow to the heart, said cardiologist Helene L. Glassberg, an assistant professor at Penn's Perelman School of Medicine.

Statins are useful both because they lower cholesterol and appear to stabilize soft plaque, she said.

So if there is a possible risk of heart disease, why not just err on the side of caution and prescribe statins, several of which are cheap generics?

Two reasons: In addition to the possible muscle pain, there also is some evidence linking statin use to memory loss.

Hence, the calcium scan.

In addition to using such scans on younger patients who might be candidates for statins, Temple's Edmundowicz also has used the test on older patients who already are taking statins but wish to stop because of the muscle pain.

Every so often, he gives them the all-clear: generally with women in their 80s who somehow have high total cholesterol levels, yet according to the test, have no coronary calcium.

The amount of radiation from a calcium scan varies depends on the type of machine.

Some older devices can expose the patient to up to five mammograms' worth of radiation. Temple is getting a new scanner this summer that will capture 256 "slices" of the heart with each snapshot, enabling a detailed image with less radiation than older machines - about the same as a mammogram, Edmundowicz said.

Winans, for one, feels it is well worth it. He will be back to use it in two years.