A Low-dose Radiation and Contrast Agent Exposure Protocol for Coronary CTA in Diabetic Patients

To assess diagnostic accuracy,image quality and renal safety of a double low-dose coronary CTA protocol at coronary artery evaluation in patients with diabetes by using invasive coronary angiography(ICA) as the reference method and to compare the results with those obtained traditional dose protocol. The study will randomly include about 400 consecutive participants aged 18 to 80 years old who had been diagnosed with diabetes and suspected coronary artery disease.All participants undergo ICA and coronary CT angiography performed with a whole-heart CT scan.Coronary segment interpretability,image quality based on a four-point Likert scale,blood indicators of renal function will be accessed between double low-dose CTA protocol and traditional CTA protocol. Investigators hypothesize that an individualized coronary CTA protocol that appropriately reduces radiation dose and contrast dose does not affect image quality and diagnostic accuracy, and can reduce the risk of kidney damage in high-risk patients.