In the clinic, patients often ask, “Doctor, do I really have coronary artery disease? Do I need an angiogram?” What is the difference between a coronary angiogram and a coronary CT test? What is the right test for me?” …… As a patient or a healthy person, it is beneficial to have a brief understanding of the diagnostic techniques for coronary artery disease. The following is an introduction to the two main tools for diagnosing coronary artery disease – “coronary angiography” and “coronary CTA”. Coronary angiography is performed by inserting a special catheter through the femoral artery in the thigh or the radial artery in the upper limb to the opening of the coronary artery, selectively injecting contrast into the coronary artery, and recording the process of imaging. It is used to determine whether there is a lesion in the coronary artery. Coronary CTA is a method of imaging the coronary arteries of the heart by using a spiral CT scan after intravenous injection of contrast and then reconstructed by computer processing. The coronary angiogram shows the lumen of the blood vessel, and it can clearly see the direction and shape of the blood vessel, the presence or absence of stenosis in the coronary artery and its degree, and evaluate the functional changes of the coronary artery, including the spasm of the coronary artery and the presence or absence of collateral circulation. It is the “gold standard” for the diagnosis of coronary artery disease. Coronary CTA visualizes the lumen and wall of the vessel and is most likely to diagnose soft plaque. It is competent for general screening. Coronary CTA requires imaging in order to be observed, and the results are closely related to the quality of the imaging, which is easily disturbed by the patient’s cardiac function, heart rate, heart rhythm, and whooping. Who is suitable for coronary angiography: People who are “highly suspected” of having coronary heart disease 1, middle-aged and elderly people with high risk factors for coronary heart disease (dyslipidemia, diabetes, hypertension, smoking, etc.) and frequent chest pain and chest tightness. 2, stable angina pectoris patients, frequent angina attacks in the last 1 to 2 weeks, can be triggered by lighter exertion: and the attack is longer, sublingual nitroglycerin is not effective. 3, patients with unstable angina, no obvious cause, angina often occurs even at rest, each attack is longer, the degree of pain is heavier, the number of attacks is frequent, sublingual nitroglycerin effect is poor, suspected of myocardial infarction precursor. 4.Patients with acute myocardial infarction, with typical symptoms, severe chest pain has been more than 30 minutes, accompanied by profuse sweating and near-death feeling, etc. Who are suitable for coronary CTA 1.Patients who are not clinically inclined to coronary artery disease but need to exclude coronary artery disease. 2.Patients who are evaluated for efficacy after intervention or bypass surgery can choose coronary CTA. Advantages of coronary angiography 1.Intuitive and accurate. 2.Reliable results and high accuracy rate. 3.Directly choose the treatment plan and judge the prognosis: medical stent implantation (PCI) or surgical bypass graft (CABG). 4.Compared to coronary CTA contrast agent dosage is less, 30-50ml. 5.No need to control heart rate and diet before the procedure; postoperative activities can be done on their own without bed rest (radial artery access). Advantages of coronary CTA Less traumatic, low cost, and can be done on an outpatient basis, but the test is affected by the patient’s heart rate and requires control of the ventricular rate. Often, some patients are easily excited, agitated and nervous during the examination, and then their heart rate increases, so they cannot complete the examination. Another problem is that even if coronary artery disease is diagnosed after the examination, interventional treatment cannot be performed immediately. Disadvantages of coronary angiography 1.It is an invasive test. 2.The cost is high compared with coronary CTA. Disadvantages of coronary CTA 1.Arrhythmia is not suitable, while spiral CT requires heart rate control. 2.High sensitivity but low specificity of calcified lesions. 3.Contrast agent needs 50-80ml. All in all, the diagnosis of any patient with coronary artery disease should be confirmed by a comprehensive assessment of symptoms, signs and auxiliary examinations!