Application of orthopedic metal artifact reduction technology in CT examination of arthroplasty / 吉林大学学报(医学版)

ABSTRACT

Objective:To investigate the metal artifact reduction effect of orthopedic metal artifact reduction (O-MAR) techonology and its improvement effect on the image quality in CT examination in the patients with arthroplasty, and to elaborate the significance of the technology in clinical diagnosis and treatment of arthroplasty.Methods:The CT data of 20patients with hip or knee prostheses was collected.There were two tube voltages in each group of CT data:120and 140Kev.There were also two groups of CT data in each tube voltage group:nonO-MAR group and O-MAR group;there were four subgroups of CT data of each case:120 Kev/-O-MAR, 120Kev/+O-MAR, 140Kev/-O-MAR, 140Kev/+O-MAR.After data collection, Mimics software was applied to conduct three-dimensional (3D) reconstruction for purpose of the qualitative and quantitative analysis of CT data.Qualitative analysis mainly included the grade of severity of metal artifact and quality of data.Quantitative analysis included the volume of metal artifact, the average CT value and standard deviation (SD) in region of interest (ROI) .ROI 1and ROI 2were chosen at the location of beam hardening artifact (radial high-density metal artifact) and photon starvation artifact (band low-density metal artifact) , respectively.Results:According to the result of3D measurement, the volumes of artifact had no significant difference between 120 Kev/-O-MAR group and140Kev/-O-MAR group (P=0.062) , but there were siginificant differences in the volumes of artifact between other groups (P＜0.05) ;O-MAR technology decreased the volume of beam-hardening artifact obviously (P＜0.05) .According to the results of two-dimensional (2D) measurement, there was no significant difference in the average CT values in ROI 2between 120Kev/-O-MAR group and 140Kev/-O-MAR group (P=0.069) , but there were significant differences in the average CT values between other groups (P＜0.05) ;O-MAR technology decreased the high-density beam-hardening metal artifact and the low-density photon-starvation metal artifact in 2D measurement.Conclusion:O-MAR technology could significantly reduce the CT metal artifact of hip and knee prostheses and increase the clinical value of CT data.