Feasibility of Reducing Radiation Dose of Coronary CT Angiography by iDose4 on 256-slice CT Under the Guide of Body Mass Index

Purpose: To evaluate the feasibility of reducing radiation dose of coronary CT angiography and improving the image quality though iDose4 on 256-slice CT combined with dose reduction techniques under the guide of the body mass index. Methods: 256-slice CT coronary angiography was performed in 74 patients who were doubted with coronary atherosclerotic disease. Patients were divided into two groups, group A was performed with fixed kV/mA and Filtered back-projection(FBP), and group B was performed with the BMI-adapted kV/mA and advanced iterative reconstruction algorithm(iDose4). The signal-to-noise radio(SNR), contrast-to-noise radio(CNR), volume CT dose index(CTDIVOL) and effective dose(E) were evaluated, respectively. Results: The mean SNRs of the images were(16.15± 3.76) and(16.65±3.47) for group A and group B respectively, and were with no significant difference between them(t=0.591,P0.05). The mean CNRs were(13.76±3.61) and(14.22±3.28) for group A and group B respectively, and were with no significant difference between them(t=0.571, P0.05).The average effective doses(ED) were(8.15±0.44) mSv and(4.18±0.72) mSv for group A and group B respectively, and were with significant difference between them(t=28.55,P0.05). Conclusions: In 256-slice CT coronary angiography, by using iDose4 of 256-slice CT combined with dose reduction techniques under the guide of body mass index, consistent image quality across patients population and optimized dose delivery to patients can be obtained, and can reduce dose can be reduced(about 49%).