Abstract: Objective: To study the effectiveness of the functional parameters of spectral CT, and to explore their clinic values of image quality in the evaluation of myocardial infarction(MI), so as to provide a novel and reliable imaging diagnostic system for early detection of MI. Methods: 30 patients with coronary heart disease were scanned with the conventional coronary CT angiography(CCTA) and the dual energy spectral imaging modes. In addition, all cases had the Cardiac MRI scan within a week. CCTA images were used to measure stenoses. The optimal contrast-to-noise ratio(CNR) and the optimal monochromatic energy levels for displaying infractions were measured from 1 min and 3 min monochromatic images. Record the image noise according to the optimal monochromatic energy levels. The results were compared with those measured from conventional 140 k Vp polychromatic images. Detect MI in MRI perfusion images and compare with those detected by CT. Results: Spectral CT have detected 36 regions of MI and had good correlation with the myocardial perfusion images of MRI(r = 100%, P = 0.00). All spectral CT-identified MI had associated coronary artery with more than 50% stenosis of the intravascular diameter(71.7% ± 16.2%). The optimal CNR for displaying infractions of 1 min and 3 min monochromatic images were significant higher than the CNR of conventional 140 k Vp polychromatic images(P < 0.05). The image noise according to the optimal monochromatic energy levels of 1 min and 3 min monochromatic images were significant lower than conventional 140 k Vp polychromatic images(P < 0.05). Conclusions: The GSI mode of dual energy spectral CT greatly improves the image quality and the efficiency of the detection of MI.