Application of adaptie statistical iterative reconstruction technology combined with low tube voltage in three phase enhanced low dose liver scanning

Objective To explore the application value of adaptive statistical iterative reconstruction (ASIR) combined with low tube voltage in three-stage enhanced low-dose scan of liver. Methods From March 2017 to November 2017, two groups which each group included 50 patients were randomly selected at the Second Affiliated Hospital of Harbin Medical University with different stages of arterial phase, delayed phase and portal vein scanning. GE Discovery CT 750 HD Liver CT Ⅲ was used during enhanced scanning. A total of 100 patients included 56 males and 44 females, aged 27-73 years old and 42 patients with hepatocellular carcinoma, 44 patients with hepatic hemangioma, and 14 patients with other diseases. The arterial and delayed period of group A patients were scanned with a low dose of 100 kV+ASIR, and the portal vein phase was conventional. Dosage scanning was 120 kV+FPP; the arterial and delayed period of group B was normal dose scanning, 120 kV+FPP, and the portal vein phase was low dose scanning, 100 kV+ASIR. At the same time, FBP reconstruction was used for all low-dose scanning phases to obtain low-dose images under normal reconstruction mode. The objective evaluation index of image quality was analyzed by completely randomized design analysis of variance, and Dunnett-t test was used to compare the two groups. For the subjective evaluation part, the rank sum test of multiple groups was used. Results ASIR combined with low tube voltage enhanced low dose scanning in the third phase of the liver, and the radiation dose decreased by 37% in the low dose group compared with the normal dose group. There was no statistically significant difference between the low dose group (100 kV+ASIR) and the normal dose group (120 kV+FPP) in subjective image quality evaluation (P>0.05); objective evaluation of image quality except for low dose(100 kV+ASIR) portal stage noise slightly worse than conventional dose group (120 kV+FBP) (low dose 10.86±1.98, conventional dose 9.40±2.12, P<0.05), the other indexes in each period were superior or indifferent to the normal dose group. Conclusion ASIR technique combined with low tube voltage can be used in the third phase of liver enhanced low-dose scanning and the image quality is improved. Key words: Tomography, X-ray computed; Radiation dosage; Adaptie statistical iterative reconstruction