1, cardiac magnetic resonance (MRI) Clinical practice shows that cardiac magnetic resonance in the diagnosis of cardiomyopathy has great advantages, in the diagnosis of viral myocarditis cardiac MRI can even be used as the gold standard. Viral myocarditis has a history of antecedent infection, arrhythmia, heart failure, serious life-threatening, cardiac ultrasound shows diffuse contraction of the myocardium, but there is no specificity, while cardiac MRI is able to see the abnormal signal shadow in the myocardium, which is very specific and sensitive to viral myocarditis, and helps in the early diagnosis and treatment. Arrhythmogenic right ventricular cardiomyopathy is a kind of cardiomyopathy in which the normal myocardium of right ventricle is replaced by fibro-fatty tissue, which is clinically manifested as repeated episodes of ventricular tachycardia, right heart failure, and even sudden death, and in a small number of patients, epsilon wave of delayed depolarization of right ventricle can be seen on ECG, and the enlargement of right ventricle can be seen by cardiac color ultrasound, but it is not specific, which makes it difficult to confirm the diagnosis, and sometimes it even requires cardiac biopsy, and now cardiac MRI can see abnormal signal shadow of right ventricle. Nowadays, cardiac MRI is able to see the abnormal signal shadow of the right ventricle, which is very helpful for the diagnosis of this disease. Cardiac MRI can also help assess the extent of infarction and microcirculation in patients with coronary artery disease, and has a certain value in predicting the prognosis of patients. Studies have shown that cardiac enhancement MRI has high resolution, can distinguish wall-permeable and non-wall-permeable myocardial infarction, and can quantitatively measure the area of infarcted myocardium. It has been reported and confirmed that in patients with acute myocardial infarction, the extent of infarcted wall-permeable myocardium defined by cardiac nuclear magnetic resonance imaging (NMRI) is capable of predicting recovery of cardiac systolic function. The application of enhanced cardiac NMR to assess the myocardial microcirculation was first seen in animal experiments, and studies in canines have found that areas of hypointensification in the NMR scan of the myocardium correspond to areas of intervention-induced no-reflow, which can reflect myocardial microcirculatory obstruction; since then, it has been found that biopsy of areas of hypointensification shown by cardiac NMR in an animal model of myocardial infarction showed microcirculatory injury in the infarcted core, as seen by which the microcirculation was obstructed by erythrocytes and necrotic debris. These results suggest that the hypointense area of cardiac enhancement MRI can reflect myocardial microcirculatory obstruction, and therefore we can use it to assess myocardial microcirculatory status in clinical practice. Cardiac CT Cardiac enhancement CT can reflect the thickness of the myocardium, and can generally reflect the myocardial perfusion. Through CTA, we can assess the stenosis of the coronary arteries, whether there is plaque, calcification, etc. Generally, in the presence of calcification, the degree of stenosis judged by coronary CTA is not accurate. Although it is not yet possible to replace coronary angiography, coronary CTA, as a non-invasive examination method, occupies a very important position in the diagnosis of coronary heart disease. The recent emergence of CT-FFR, as a noninvasive method of assessing coronary flow reserve fraction, has been shown in existing studies to accurately reflect whether coronary stenosis is ischemic or not, and to provide a sufficient basis for the next step of treatment. Non-invasive assessment of flow reserve fraction is a new non-invasive testing system that provides physicians with a way to more accurately assess which lesions require invasive testing than coronary CTA, which first obtains three-dimensional images of the coronary arteries with coronary CTA, and then computers simulate coronary blood flow based on coronary artery anatomical information with dedicated software to calculate the simulated FFR value, which is non-invasive FFR value The noninvasive FFR value has a good correlation compared with the invasive FFR value measured in coronary intervention. Therefore, I believe that noninvasive CT-FFR will play a greater role in the diagnosis and treatment of coronary artery disease in the future. Positron emission tomography (PET) PET can provide accurate quantitative information on myocardial perfusion through myocardial uptake of tracer imaging. Commonly used tracers include 15O-labeled water (15O-water), 13N-labeled ammonia (13N-ammonia), etc. When injected intravenously, the retention of the tracer is inversely proportional to the blood flow, and the perfused blood flow per minute per gram of myocardium can be deduced from this.PET is considered to be the gold standard for myocardial perfusion blood flow detection. PET is considered the gold standard for myocardial perfusion flow measurement. Based on the accuracy of PET in detecting myocardial perfusion flow, it can be used to assess myocardial microcirculation in clinical practice. PET has been used to assess myocardial perfusion in microvascular angina, and we can also use PET to assess myocardial microcirculatory perfusion in patients with acute myocardial infarction after vascularization. However, PET examination is expensive and time-consuming, which limits its promotion in clinical practice.