[Comparative study on image quality of third-generation dual-source CT pulmonary angiography combined with advanced modeled iterative reconstruction].

Objective: To quantitatively evaluate the quality of advanced modeled iterative reconstruction (ADMIRE) combined with 70 kVp and linear blending images in low dose dual energy (70 kVp/sn150 kVp) pulmonary angiography. Methods: A total of 74 cases with normal BMI underwent dual-source CT dual-energy pulmonary angiography with small amount of contrast medium (30 ml) from 2015 to 2017 from the First Affiliated Hospital of Zhengzhou University were randomly assigned to protocol Ⅰ(100 kVp/sn140 kVp) or protocol Ⅱ(70 kVp/sn150 kVp). 70 kVp+ ADMIRE (group 1), linear blending+ ADMIRE (group 2), 100 kVp+ SAFIRE (group 3) images were obtained. CT value and noise standard deviation (SD) of pulmonary arteries were measured in pulmonary trunk artery, left pulmonary artery and left superior pulmonary artery, then SNR and CNR were calculated. Radiation dose parameters (CTDIvol, DLP) were recorded. Results: CT values of pulmonary artery of group 1 were significantly higher than those in group 2 and 3 (both P <0.05). In group 2, SD value of pulmonary artery was lower than that of group 1 and 3(both P <0.05). SD value of pulmonary trunk and left pulmonary artery in group 1 was higher than that in group 3 ( P <0.05), SD value of left superior pulmonary artery had no significant difference between group 1 and group 3 ( P >0.05). SNR and CNR value in group 1 and group 2 had no statistical difference, but they were both higher than that in group 3 (both P <0.05). The effective dose of protocolⅠwas 46% lower than protocol Ⅱ. Conclusion: ADMIRE combined with 70 kVp and linear blending images are better than SAFIRE combined with 100 kVp images, and radiation dose is reduced.70 kVp/sn150 kVp with small amount of contrast medium (30 ml) is a feasible dual energy pulmonary artery scanning protocol.