Clinical Study On Coronary CT Angiography Using 100kVp With ASIR-V

Objective(1)To compare radiation dose of low tube voltage(100kVp)and conventional voltage(120kVp)which using the revolution CT coronary angiography with prospective ECG gated and analyze the clinical value of reducing coronary radiation dose by anterior coronary artery imaging under the condition of revolution CT low voltage.(2)To compare the reconstructed image quality of low dose radiation conditions using different percentage ASiR-V reconstruction,and choose the weight of best image quality.Methods Collect 120 patients underwent coronary CT angiography in the The First Affiliated Hospital of Guangxi Medical University command from November.2016 to February.2017,while the patients' BMI range from 18 to20kg/m2.The patients were taken supine position and connected with ECG gating,using GE revolution CT scanner made in USA.Patients were randomly divided into 2 groups:Group 1(100kVp group),100 kVp,Automatic mA,contrast media: Nonionic iodinated contrast medium 370 mg I/ml.Group 2(120 kVpgroup),120 kVp,Automatic mA,contrast media: Nonionic iodinated contrast medium 370mgI/ml.The image were reconstructed with filter back projection(FBP)and 20%,40%,60 %,80%,100% ASiR-V reconstruction.The original data were transmitted to AW4.6 workstation for image processing.Subjective evaluation of image quality was carried out by 4 point scoring method,and the CT values of the aortic root and the two sides of the coronary artery were measured and recorded.The objective assessment of image quality includes noise,contrast to noise ratio,signal to noise ratio.The ED(Effective Radiation Dose)values of each patient were calculated.All data were analyzed statistically using SPSS 17 software.RESULTS(1)The CT values of two segments of coronary angiography can meet the demands of clinical diagnosis,and the image quality of each segment is more than 2 points.The radiation dose of group 1(100kVp)was lower than group 2(120kVp),and the difference of ED value between the two groups was statistically significant(P<0.05).(2)There was a significant difference in the subjective score of image quality in 100 kVp group with different weights of ASiR-V reconstruction(P<0.05).20%,40%,60%,100%ASi R-V image noise with respect to FBP decreased by 8%,respectively,by 14%,23%,31%,42%,(P<0.05).And 60% and 80% ASIR-V reconstruction of coronary artery image quality is the best.CONCLUSIONS(1)BMI index in the range of 18 ~ 25kg/cm2 with revolution CT using non-ionic iodine contrast agent under the condition of100kVp(370mg I/ml)CCTA examination can obtain better image quality,meet the needs of clinical diagnosis,and significantly reduce the radiation dose to patients.(2)Compared with the FBP reconstruction,the image quality of 60%and 80%ASIR-V is the best.