Abstract: Objective:To explore the diagnostic value of gemstone spectrum CT for coronary artery stenosis and myocardial ischemia. Methods:A total of 34 patients with coronary heart disease(23 males and 11 females) who came to our hospital from March 2018 to November 2019 were collected. All patients underwent a CTA scan of the coronary spectrum CT, and were given a nuclide in a week-Myocardial perfusion examination. The post-processing software was used to determine the iodine content and the slope of the spectrum curve in the central region of perfusion defect and the normal region of perfusion at the same level, and SPECT was used as the reference standard to evaluate the diagnostic efficacy of spectrum CT for myocardial ischemia using Pearson's correlation analysis. Results:Analysis of 34 patients showed that the proportion of stenotic segments above moderate coronary artery was 79/544. Spectrum CT detected 41 myocardial perfusion defect areas, and SPECT found 33 defect areas, and the two had good correlation(r=0.979,P=0.04). Spectrum CT was used to determine the iodine content and the slope of the spectrum curve in normal perfusion areas were(14.49 ±5.20) mg/mL and 1.29 ±0.39. The iodine content and the slope of the spectrum curve were(-12.59 ±3.32) mg/mL and-0.98 ±0.35 in the abnormal area. The difference between the two was statistically significant(P<0.05). Conclusion:Gemstone CT is useful for assessing myocardial ischemia through the analysis of myocardial iodine content in the first pass while evaluating coronary artery stenosis.