Invasive coronary angiography (CA) has long been considered the “gold standard” for the diagnosis of coronary artery disease. However, large-scale CA has a low positivity rate and lacks functional evaluation. Diagnostic CA alone not only causes great physical pain to patients, but also results in a waste of social resources. How to replace purely diagnostic CA to guide the diagnosis and treatment of coronary heart disease has been a hot topic of concern in the cardiovascular community at home and abroad. In recent years, as 64-row spiral CT and dual-source spiral CT have been put into clinical application, the sequential diagnostic procedure of CT coronary angiography (CT-CA) combined with radionuclide myocardial imaging and anatomical imaging combined with functional imaging to guide the diagnosis and treatment of coronary heart disease has begun to emerge. Patients suspected of coronary artery disease by history, symptoms and ECG examination enter the sequential diagnostic procedure. With the rapid development of CT scanning technology, the temporal and spatial resolution of CT has been significantly improved. CT-CA can clearly display the anatomical structure of coronary arteries and evaluate the stenosis of 1.5 mm diameter coronary arteries. The sensitivity, specificity, positive predictive value and negative predictive value for the diagnosis of coronary stenosis were 94%, 97%, 87% and 99%, respectively. Compared with conventional CA, CT-CA can not only determine the degree of luminal stenosis, but also show the coronary artery wall and atherosclerotic plaque, which is unmatched by CA. one great advantage of CT-CA is the ability to determine the composition of the plaque based on CT values. The CT values of lipid, fiber and calcium in plaque were 49±22Hu, 91±22Hu and 391±156Hu, respectively. since the stability of plaque depends on its composition, it is very important to show the different components in plaque according to CT to understand the pathological evolution of plaque, predict the risk level of plaque and guide the clinical treatment. In view of the very high negative predictive value and easy operability of CT-CA, CT-CA is used as the first step of the sequential diagnostic procedure. If CT-CA is completely normal, the possibility of coronary artery disease can be basically excluded. If CT-CA reveals luminal stenosis <50%< span="">, mild coronary atherosclerosis is considered, and patients are often advised to improve their lifestyle and intensify conservative medical therapy. If CT-CA reveals luminal stenosis >50%, or if a large number of calcified plaques interfere with the determination of luminal stenosis by CT-CA, then the second step of the sequential diagnostic procedure (CT-CA) is performed. Special case: If CT-CA reveals luminal stenosis >50% and the plaque CT value is very low, combined with the patient’s history of unstable angina, percutaneous transluminal angioplasty (PTCA) and stent implantation can be performed directly. The second step, radionuclide myocardial imaging Radionuclide myocardial imaging mainly refers to adenosine-loaded nuclide myocardial perfusion imaging (MPI). After injection of radioactive tracer, viable myocardial cells extract the nuclide from the blood and retain it in the myocardial cells for a period of time. The amount of photons emitted from the myocardium is proportional to the tracer uptake, which is related to the amount of blood perfusion. In contrast, adenosine, a drug that acts on A2 receptors on the surface of vascular endothelial cells, dilates coronary arteries and increases normal blood flow 3 to 5 times, and fails to increase blood flow in coronary stenosis. Combining these two mechanisms, adenosine loading MPI compares myocardial blood perfusion in both loading and resting states to identify whether the myocardium is ischemic. If the ventricular myocardium is compared to a farmland, CT-CA and CA both check whether the irrigation channels are open, while adenosine loading MPI directly detects whether the seedlings (i.e. cardiomyocytes) are dehydrated (blood), and the two complement each other and work closely together, one cannot be without the other. Adenosine loading MPI distinguishes patients who enter the second step of the sequential diagnostic procedure into two groups: those with and without ischemia. Patients in the non-ischemic group were recommended lifestyle changes and aggressive medical therapy with regular review, while patients in the ischemic group were recommended either PCI and coronary artery bypass grafting (CABG) or lifestyle changes and aggressive medical therapy with regular review, depending on the size of the ischemic area. In addition, for multi-branch lesions shown by anatomical examination, adenosine-loaded MPI can also perform ischemic localization to find the offender vessel and offender lesion and guide PCI or CABG with targeting. Radionuclide myocardial imaging also includes 18F-deoxyglucose (FDG) PET myocardial metabolic imaging. It is now recognized as the “gold standard” for determining myocardial survival, and perfusion-metabolism mismatch at the infarct site is a reliable indicator of myocardial survival. In patients with ischemic cardiomyopathy and old myocardial infarction, determination of myocardial viability can help in the selection of next treatment strategy and prognosis. If viable myocardium is still present, the patient may benefit from PCI or CABG as the next step; if no viable myocardium is present, medical treatment is often recommended. Patients screened for PCI or CABG in the second step of the sequential diagnostic procedure will proceed to invasive procedures; patients with more complex coronary lesions on CT-CA will undergo either PCI or CABG after CA, while patients with more isolated lesions on CT-CA may opt for direct PCI. The sequential diagnosis of coronary artery disease is of great clinical importance in screening, risk stratification and guiding treatment strategies. With the rapid development of imaging technology, further improvement of temporal and spatial resolution of CT can be expected to overcome the constraints of calcified lesions, rapid heart rate and arrhythmias; at the same time, the myocardial specificity of nuclei can be improved; and even the integration of CT-CA with MPI or PET, integrating anatomical and functional imaging, sequential diagnostic methods can replace purely diagnostic CA to guide the diagnosis and treatment of coronary artery disease. is just around the corner!