Calcium scan concerns

Ask the doctor

Q. I'm a 70-year-old man with no signs of any heart problems, and my blood pressure is low (110/70). I recently had a coronary artery calcium scan and received a score of 480. According to my cardiologist, that means I have a lot of plaque in my heart arteries. He increased the dose of my statin and recommended an echocardiogram stress test. The results showed no underlying heart issues, but I'm still concerned. How accurate are calcium scans?

A. A coronary artery calcium scan is a special CT scan that highlights calcium deposits in the plaque that lines and clogs the arteries feeding the heart. In general, calcium scans are very accurate. Unlike some other imaging tests, the results are unlikely to be either falsely negative (that is, the test indicates no problem when there actually is one) or falsely positive (the test indicates a problem when there isn't). That's because the results are literally black and white. The scanner takes multiple pictures of the heart in thin sections, which are then combined to produce a view that reveals calcium deposits as white specks. The machine's software then calculates a score based on the amount of calcification. Any score above zero indicates the presence of plaque.