A nuclear stress test detects advanced disease when an artery has developed more than 60% obstruction of the lumen. The vast majority of heart attacks are due to plaque rupture of an artery with only mild narrowing are not detectable by nuclear stress test.

Ultrafast cardiac CT for coronary artery calcification is a simple 30 second test that requires IV injection of any isotope or contrast and no special patient preparation.

Many asymptomatic patients with normal nuclear stress have subclinical disease and in fact at high risk.

Because 650,000 of the 1,100,000 hearts attacks that occur in the US annually are first heart attacks, and because preventive treatment is highly effective, the ability to detect as many of these asymptomatic patients as early as possible is an important diagnostic tool for primary prevention. Cardiac CT for coronary calcium score is just tool.