Application of 80 kV combination of pre- and post- adaptive statistical iterative reconstruction-V in abdominal CT enhancement examination

Abstract:

Objective: To explore the best combination of adaptive statistical iterative reconstruction-V（ASiR-V） for abdominal computer tomography（CT） enhancement under 80 kV tube voltage. Methods: The data of normal or thin patients with body mass index（BMI）≤24.9 kg/m² who took enhanced abdominal CT examination were collected，and they were randomly divided into control group and low-dose group，each with 40 cases. The 120 kV tube voltage of the control group was scanned with the 0% pre-ASiR-V，and after the scanning，filtered back projection（FBP） and 20%，40% and 60% post-ASiR-V were used for image reconstruction. In the low-dose group，80 kV tube voltage，arterial phase，venous phase and delayed phase were respectively used with 20% pre-ASiR-V combined with 20%，40%，60% and 80% post-ASiR-V，40% pre-ASiR-V combined with 40%，60% and 80% post-ASiR-V and 60% pre-ASiR-V combined with 60% and 80% post-ASiR-V for image reconstruction. The CT values，contrast to noise ratio（CNR），image noise objective score and subjective image parameters of the two sets of images were compared，and the radiation dose index was recorded. Results: There were statistically significant differences in CT values between the two groups of images（P<0.05）. There was no statistically significant difference except for A20，A40，V40，D60 CNR between the low-dose group and the control group（P>0.05），and the CNR values of the remaining images of low-dose group were higher than those of the control group. There was no significant difference between the two groups of image noise except for A60，V60 and V80（P>0.05），and the image noise of the other low-dose groups was higher than that of the control group. Except for the 80% post-ASiR-V，the image quality was poor，and the subjective scores of the other two groups of images were all greater than 3 points，which meet the diagnosis. Compared with the control group，the effective dose（ED） of the low-dose group in the arterial phase，venous phase and delayed phase decreased by 66.81%，67.24% and 70.61%，respectively. Conclusion: For normal or thin patients patients with BMI ≤ 24.9 kg/m²，using 80kV tube voltage combined 40% pre-ASiR-V with 60% post-ASiR-V can obtain images meeting the needs of imaging diagnosis under the condition of reducing the radiation dose，and realize the principle of individualized scanning.