The coronary calcium scan was invented by Dr. Arthur Agatston, who is better known for the popular South Beach Diet. Also called a “heart score,” the test measures the amount of calcium in the three coronary arteries that bring oxygenated blood to the heart, which then pumps that blood to the rest of the body.

Over time, these arteries can collect deposits of calcium and a substance called plaque, which is made up of fats and cholesterol. Calcium in the coronary arteries is an indication of chronic inflammation, a condition that can cause a bit of that plaque to rupture and form a clot in a blood vessel, blocking blood flow and resulting in a heart attack.

To determine calcium score, a CAT scan that has been outfitted with special software is used. As images are taken of the heart, calcium is measured. The more calcium there is, the higher a person’s score, and the more severe his or her heart disease:

• Zero — no identified disease

• 1 to 99 — mild disease • 100 to 399 — moderate disease

• 400 and above — severe disease