Abstract:Objective To explore the evaluation value of coronary CT-derived fractional flow reserve (CT-FFR) combined with cardiac magnetic resonance (CMR) multimodal imaging in assessing myocardial ischemia and myocardial infarction in patients with coronary atherosclerotic heart disease (CHD), and to provide imaging evidence for clinical diagnosis and treatment. Methods A retrospective selection was made of 120 patients with suspected myocardial ischemia and 60 patients with suspected myocardial infarction who visited Nanjing Jiangbei Hospital from October 2020 to October 2025, all of whom underwent coronary CT angiography (CCTA) and CMR multimodal imaging and delayed enhancement examination. Based on coronary angiography (CAG) and clinical comprehensive diagnosis, the diagnostic value of CT-FFR gained from CCTA, and CMR multimodal imaging for myocardial ischemia and myocardial infarction, respectively in patients with CHD was analyzed. Results After hospitalization, according to CAG and comprehensive clinical diagnosis, among 120 patients with suspected myocardial ischemia, 90 were confirmed myocardial ischemia; among 60 patients with suspected myocardial infarction, 42 were confirmed myocardial infarction. CMR multimodal imaging showed that there were abnormal signals in the myocardium, and definite abnormal enhancement was seen in delayed enhancement, which were the image characteristics of myocardial ischemia and myocardial infarction, respectively. CT-FFR value <0.75, combined with the degree of coronary artery stenosis and plaque observed on CCTA, was a prompt warning of the possibility of myocardial ischemia and myocardial infarction. Based on comprehensive clinical diagnosis, the sensitivity, specificity, and accuracy of CMR multimodal imaging in diagnosing myocardial ischemia showed no statistically significant difference compared with CT-FFR (P>0.05). However, for the diagnosis of myocardial infarction, the sensitivity (92.86% vs 69.50%, χ²=7.721, P=0.005) and accuracy (91.67% vs 70.00%, χ²= 9.090, P=0.003) of CMR were higher than those of CT-FFR, while the specificity showed no difference between the two (88.89% vs 72.22%, P=0.402). left Conclusion CT-FFR combined with CCTA can quickly capture information on coronary anatomical stenosis and functional ischemia; meanwhile, CMR multimodal imaging has high specificity and sensitivity for myocardial conditions, especially myocardial infarction. The combination of these two has high clinical value in detecting myocardial ischemia and myocardial infarction in patients with CHD.