A coronary CTA can generally be done within half an hour. Some hospitals may require patients to have an iodine allergy test, so it may take longer. Coronary CTA is mainly used to detect coronary artery disease. During coronary CTA, patients should maintain emotional stability and not be overly nervous. The required heart rate is below 75 beats/min. If the heart rate is too fast, coronary CTA cannot be performed due to poor visualization. Patients should observe whether they have chest tightness, shortness of breath, or skin rash or itching after the completion of coronary CTA, which may be due to allergy to the contrast agent. After the coronary CTA, patients should drink more water and urinate more within 24 hours afterwards to promote the excretion of the contrast agent. If the patient usually takes metformin due to diabetes, it is recommended that the patient stop taking metformin for 48 hours before performing coronary CTA.