CCTA differs from the traditional methods of assessing heart attack risk in two very important ways.

First, unlike stress tests, CCTA can assess all degrees (mild, moderate, and severe) of coronary artery disease. Secondly, CCTA is highly accurate, with a negative predictive value of 99%. Stress tests miss early coronary artery disease in patients because they assess function and do not demonstrate anatomy. Since heart function is not affected until there is at least 65-percent obstruction of a coronary vessel, the stress test is only positive with severe disease. To put it simply, CCTA demonstrates the extent of disease in the vessel wall and can detect CAD much sooner than the stress test. 

CCTA is even superior to coronary angiography for assessing heart attack risk. Selective coronary angiography, an invasive technique, is superb for confirming the extent of coronary artery stenosis and directing the trans-catheter or surgical therapy of coronary artery disease. However, since angiography only sees the vessel lumen (the “doughnut hole”), it cannot visualize plaque in the wall of the coronary artery. Again, it is the rupture of the soft, vulnerable plaque in the wall of the artery (the “doughnut”) that leads to acute heart attacks.