A Study on Image Quality and Dose of Coronary CT Angiography with ECG Window Acquisition Range Unit Conversion

The purpose of this study was to evaluate radiation dose and image quality compared to those of the relative delay scan when using an absolute delay scan after converting the ECG window acquisition unit in coronary CT angiography. We used chest phantom and ECG simulator through the phantom study. Patient study was conducted on 90 sinus rhythm patients and 76 atrial fibrillation patients. The absolute delay scan was performed after unit conversion based on the average heart rate. After setting the region of interest, quantitative evaluation of image quality was made, qualitative evaluation was made by two observers. The dose was evaluated using the CTDIvol and DLP. There were no significant differences in quantitative values in terms of the phantom study. At an irregular heart rate 79, the CTDIvol of the experimental group decreased by 18% compared to the control group, the DLP decreased by 17.4% compared to the control group.(P<0.05) As a result of patient study, there were no significant differences in quantitative values in terms of the patient study. The CTDIvol of the artrial fibrillation experimental group decreased by 33% compared to the control group, the DLP decreased by 30% compared to the control group.(P<0.05) As a result, when examining coronary CT angiography of patients with atrial fibrillation, it will help reduce the patient’s dose without affecting the image quality if the scan range is set after converting the ECG window acquisition unit to milliseconds based on the average heart rate.