Cardiac ct mainly examines the coronary arteries of the heart to see if there is plaque, calcification and narrowing of the lumen, to clarify the degree of narrowing of the lumen, thus helping to diagnose coronary heart disease. Cardiac ct examination, is through the observation of the heart coronary artery situation, to understand the coronary artery is not the existence of plaque, lumen narrowing, or even blockage and other conditions. If the coronary arteries are only mildly narrowed, with the degree of narrowing within 50%, it generally indicates that the coronary arteries have atherosclerosis. If the coronary arteries have moderate to severe stenosis, that is, the degree of stenosis is more than 50%, it can help the doctor to diagnose coronary artery disease. In clinical practice, it is generally recommended that patients have both a cardiac ct and a cardiac color Doppler ultrasound, which can more accurately make the diagnosis and help guide the use of medication.