[Application of preset adaptive statistical iterative reconstruction-V in dual-enhanced abdominal CT]

Objective: To analyze the effect of preset adaptive statistical iterative reconstruction-V (ASIR-V) on image quality and radiation dose in dual-enhanced abdominal CT and to investigate the optimal ASIR-V in clinic use. Methods: From February 13 to April 30 in 2017, one hundred and eighty patients who received up abdominal CT scan in the First Affiliated Hospital of Zhengzhou University were collected prospectively. All patients underwent arterial phase (AP) and portal venous phase (PVP) enhanced abdominal CT(120 kVp, noise index 10) and were randomly divided into 6 groups according to random number table (A-F, 30 cases in each group). In group A-F, 0-50% preset ASIR-V (an interval of 10%) was applied, respectively. Qualitative parameters (subjective image quality, diagnosis confidence and radiation dose) and quantitative parameters[image noise, CT number and contrast to noise ratio (CNR)]were measured and compared among the groups by using one-way analysis of variance or Kruskal-Wallis H test. Results: The CT dose index volume (CTDIvol) decreased with the increasing of preset ASIR-V. The effective radiation dose (ED) was significant different among groups (F=27.598, P<0.05), and the ED of group B-F dropped by 10.8%, 21.7%, 31.2%, 44.9% and 61.9% respectively when compared with that in group A. Group E showed the optimal image quality (Z=18.675, 27.548, 19.761, all P<0.05) and diagnosis confidence(Z=21.387, 17.693, 22.459, all P<0.05) in plain scan, AP and PVP phases. There was no significant differences in image noise and CT value of liver, pancreas and muscle among groups (F=1.468, 0.337, 0.592, 0.284, all P>0.05). There were significant differences in CNRs in liver and portal vein in PVP phase among the groups (F=3.980, 4.681, both P<0.05). Conclusion: In abdominal CT, 40% preset ASIR-V can provides the best image quality and it can reduce radiation dose for 44.9%.