Cardiac angiography and cardiac CT are both ways to diagnose coronary atherosclerotic heart disease, but there are still some differences between the two: 1. Invasive and non-invasive, cardiac CT is a non-invasive test that needs to be performed in a CT room. CT imaging and computerized three-dimensional reconstruction are performed by injecting a contrast agent, which finally shows the alignment of the heart vessels as well as the presence or absence of stenosis and the degree and location of stenosis. A cardiac angiogram is an invasive test that is performed in a catheterization laboratory by puncturing the radial or femoral artery. If the heart vessels are completely normal as diagnosed by cardiac CT, the judgment at this time is generally accurate and does not differ much from cardiac angiography. However, if cardiac CT diagnoses that the blood vessels of the heart are stenosed, the judgment of the degree of stenosis is easily inaccurate at this time, while cardiac angiography is known as the gold standard because it observes a dynamic image, so the judgment of the degree of stenosis is accurate.