Abstract: AIM:To evaluate the effects of adenosine stress cardiac magnetic resonance (CMR) imaging on the diagnosis of early coronary artery disease (CAD). METHODS: Thirty-four patients with nonclinically acute coronary syndrome but with angiographically varying degrees of stenosis of coronary arteries underwent rest and adenosine-stress and delayed-enhancement CMR imaging at 3.0 tesla. Patients were divided into three groups according to the outcomes of standard selective coronary angiography. In group 1, the stenosis diameter of the coronary artery was defined as >75%. In group 2, the stenosis diameter of the coronary artery was defined as 50-75%, and in group 3 the stenosis diameter of the coronary artery was defined as <50%. The changes of myocardial magnetic resonance perfusion under different conditions were comparatively analyzed. RESULTS: Rest CMR imaging showed that the main presentation of myocardial ischemia was the decrease of myocardial perfusion in patients with nonacute coronary artery syndrome. The total positive rate was 38% (13/34), and no significant difference was found between various groups with coronary artery stenosis. Compared with rest CMR imaging, adenosine-induced stress perfusion CMR imaging increased the positive rate of myocardial ischemia (62%, 21/34). A significant difference was found in the detection of myocardial ischemia between rest CMR and adenosine stress CMR (P<0.01). No delayed gadolinium enhancements were seen at delayed CMR imaging in all 34 patients. CONCLUSION: There was no positive correlation between extent of myocardial ischemia and degree of coronary artery stenosis at rest CMR imaging. Adenosine stress CMR imaging can significantly increase the positive rate for the detection of myocardial ischemia, which is helpful in the early diagnosis of CAD.