1. Diagnosis of coronary artery disease: mainly used for initial screening of coronary artery stenosis and its plaque in outpatients, such as: (1) patients with chest pain, uncertain or unreadable ECG, and patients unable to perform exercise test; (2) evaluation of coronary artery disease risk in low-risk patients with emergency chest pain and Vermingham medium/high risk population; (3) ambiguous results of stress exercise test, performing CTA can screen for coronary artery disease or to detect other causes of symptoms. It should be noted that conventional coronary angiography (CAG) remains the gold standard for the diagnosis of coronary artery stenosis and is required for PCI and CABG. 2. Coronary artery bypass graft (CABG) evaluation: including preoperative evaluation of the calcification of the internal mammary artery (IMA) and ascending aortic wall, as well as the usual postoperative condition of the bypass vessels. 3. Coronary artery evaluation before non-coronary cardiac surgery: to exclude significant coronary artery disease before non-cardiac surgery. 4.Evaluation of lung and pulmonary vessels: including the diagnosis of pulmonary embolism and pulmonary stenosis lesions, etc. 5.Diagnosis of aortic lesions: including fine preoperative diagnosis and postoperative follow-up of aortic coarctation, etc. 6.Diagnosis of congenital heart disease: CTA can make fine observation morphologically and structurally, especially for intrinsic coronary artery and pulmonary artery development, pulmonary vein malformation drainage, aortic arch and descending aortic malformation, as well as body-pulmonary collateral vessels, which is a powerful supplement to imaging and ultrasound. Congenital coronary artery developmental anomalies Although congenital coronary artery developmental anomalies are less common, they are an important cause of sudden myocardial infarction or sudden death and are the second leading cause of sudden death in young athletes. Conventional coronary angiographic techniques are difficult to operate, while noninvasive CT methods are useful to show the coronary artery course and origin. 1. Abnormal coronary artery opening and origin: mainly in the following cases: (1) opening in the ascending aorta, with an incidence of about 6%; (2) multiple openings in the left and right coronary arteries, with an incidence of about 0.41%; (3) single opening (single crown) malformation, with a very low incidence of about (4) coronary artery originating from the pulmonary artery, with an incidence of about 1/300,000; (5) a coronary artery emanating from another coronary sinus, such as the right coronary artery emanating from the left coronary sinus, the left coronary artery emanating from the right coronary sinus, the anterior descending or gyral branch emanating from the right coronary sinus, or the left or right coronary artery emanating from the non-coronary sinus; the incidence is about 0.03-0.17%; 2. Coronary artery myocardial bridges, accounting for 0.5-2.5% of coronary angiograms, but pathologically found in 15-85% of specimens with the presence of myocardial bridges; 3. Coronary artery fistula: both left and right coronary arteries can occur, commonly left atrial fistula, right atrial fistula and right ventricular fistula. The incidence is about 0.1-0.2%. 4. Left and right coronary artery connection: In the absence of severe stenosis or occlusion of the coronary artery, the left and right coronary arteries are connected by thicker branches, similar to the collateral circulation vessels. 5. Connection of coronary arteries with extrapericardial vessels: mainly seen with bronchial arteries, intercostal and internal mammary arteries, internal mediastinal arteries, etc., mainly seen when there is severe stenosis or occlusion of coronary arteries.