What is a calcium scan for heart disease, and who should undergo the test?

A coronary artery calcium scan is a CT scan that looks for calcium deposits in the arteries that supply the heart. It is noninvasive and is often promoted commercially – for roughly $300 per scan – as a way to screen for the buildup of plaque in arteries, a condition called atherosclerosis. Calcium often – though not always – builds up in plaque the longer it sits in artery walls. Thus a high score on a calcium scan can indicate long-lasting plaque and – perhaps – elevated risk of heart attacks or sudden death.