Application research of coronary CT angiography using low tube voltage in patients with a normal body mass index / 实用放射学杂志

ABSTRACT

Objective To assess the image quality of coronary CT angiography(CCTA) by using high-pitch spiral CT under 80 kV in patients with a normal body mass index(BMI), and to investigate the feasibility of low radiation dose.Methods 60 patients,who suspicious coronary artery diseases and BMI between 18.6-25.0 kg/m2 underwent CCTA in our hospital.All patients were randomly divided into group A and group B(each with 30).Patients in group A were given 100 kV CCTA and filter back-projection algorithm (FBP), and patients in group B were given 80 kV CCTA and iterative reconstruction(IR).CT values of aortic root, right coronary artery (RCA), left anterior descending artery (LAD), left circumflex (LCX) and standard deviation (SD) were measured.Then signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated.All images were given quality subjective scoring by using 3-score method.The CT dose index was recorded and effective radiation dose (ED) was calculated.Results ED of group A and group B was 0.8 mSv and 0.41 mSv, respectively.Statistically significant difference was found between these two groups.In the study, SD was (28±6) HU in group A and (46±9) HU in group B, and the difference was statistically significant between the two groups.The CT values of aortic root, RCA, LAD and LCX under 80 kV were significantly increased, and the difference was statistically significant between the two groups.There was no statistically significant difference between two groups in RCA-SNR, LAD-SNR and RCA-CNR.But in LCX-SNR, LAD-CNR, LCX-CNR, there was statistically significant difference between two groups.There was no significant difference between the two groups in coronary artery segments which could be used for diagnosis.Conclusion For patients with a normal BMI, CCTA using Flash spiral CT under 80 kV could diagnose coronary artery disease and significantly reduce the radiation dose.