Coronary artery disease is not new to us, it is a common condition in cardiovascular medicine. Once the body suddenly feels pain in the precordial region, it is usually associated with coronary artery disease. The first step in the treatment of coronary artery disease is to understand the degree of coronary stenosis, i.e., what percentage of the coronary artery is occluded, in order to determine what treatment the patient needs. To do this, it is not possible to rely solely on an electrocardiogram. How can you see the degree of coronary artery stenosis? There are two methods commonly used today, which are coronary CT and coronary angiography. Some patients do not know much about coronary CT and coronary angiography, wondering if they are the same and if there is any difference. What are they suitable for? Today we will understand: 1, coronary CT is through the CT film, after digital imaging simulation of the coronary system, showing whether there is a lesion in the coronary arteries, non-invasive examination, is a non-invasive examination, through the CT scan to determine whether there is a narrowing of the coronary arteries, but it is only a means of examination, even if the lesion is found can not be dealt with. 2.Coronary angiography can detect coronary lesions and is the gold standard for coronary artery disease examination. During the dynamic examination, it can clearly discover the stenosis site and degree of heart vessels and the blood supply of the whole vessels. However, it is an interventional examination, which is a kind of surgery with certain risks, but it is more accurate in determining the degree of coronary lesions and can eliminate coronary stenosis by intracoronary stent implantation after lesions are found. 3.CT examination is a static examination method, which can find the size of coronary plaque and whether it is calcified, but cannot accurately calculate the degree of coronary stenosis. Compared with coronary angiography, the amount of radiation for coronary CT examination is larger. 4.If there is no obvious abnormality in coronary CT examination, there is no need to do coronary angiography again; if coronary CT finds that there is stenosis in blood vessels, coronary angiography is needed again to clarify the degree of coronary stenosis. It can be seen that coronary CT is only a means of examination, while coronary angiography is not only a means of examination, but also a means of treatment. Coronary CT and coronary angiography are not the same. Generally speaking, it is necessary to do coronary CT first, and only after the stenosis is found, it is necessary to do coronary angiography!