RESUMO
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.
RESUMO
Objective:To discuss the accuracy of stereolithography (SLA)-3D printing model in orthopedics and maxillofacial surgery,and to clarify the reliability of its clinical application.Methods:A total of 33 cases of SLA-3D printing models were randomly included (10 long bones,13 irregular bones and 10 prostheses),and the CT scanning and three-dimensional reconstruction were performed.According to the clinical application characteristics of the models,the max height (MH),max length (ML),max width (MW),width of the trochlear (WT),length of the trochlear (LT),length of the glenoid cavity (LGC),width of the glenoid cavity (WGC),distance of pubic tubercle-anterior superior iliac spine (DPI),diameter of the acetabulum (DA),diameter of the marrow cavity (DMC),anterior height of right ramus (AHRR) and posterior height of right ramus (PHRR) were selected to measure the original data and model data,respectively.The absolute / relative errors were calculated.Intraclass correlation coefficient (ICC) was used to evaluate the consistency of the data.The three-dimensional error analysis of the prosthesis model was carried out.Results:There were no significant differences in the anatomical parameters except MW of irregular bone (P＞0.05) in 33 cases of SLA-3D printing model.The values of ICC were all greater than 0.950;the maximum values of absolute / relative errors were-0.58 mm and-1.37％,respectively;the maximum 3D error of prosthesis model was 0.237 mm,and the average value was 0.132 mm.Conclusion:The CT data of SLA-3D model is highly consistent with the original data,and it is accurate and reliable in the diagnosis and treatment of the diseases in orthopedics and maxillofacial surgery.
RESUMO
Objective:To discuss the accuracy of stereolithography (SLA)-3D printing model in orthopedics and maxillofacial surgery,and to clarify the reliability of its clinical application.Methods:A total of 33 cases of SLA-3D printing models were randomly included (10 long bones,13 irregular bones and 10 prostheses),and the CT scanning and three-dimensional reconstruction were performed.According to the clinical application characteristics of the models,the max height (MH),max length (ML),max width (MW),width of the trochlear (WT),length of the trochlear (LT),length of the glenoid cavity (LGC),width of the glenoid cavity (WGC),distance of pubic tubercle-anterior superior iliac spine (DPI),diameter of the acetabulum (DA),diameter of the marrow cavity (DMC),anterior height of right ramus (AHRR) and posterior height of right ramus (PHRR) were selected to measure the original data and model data,respectively.The absolute / relative errors were calculated.Intraclass correlation coefficient (ICC) was used to evaluate the consistency of the data.The three-dimensional error analysis of the prosthesis model was carried out.Results:There were no significant differences in the anatomical parameters except MW of irregular bone (P＞0.05) in 33 cases of SLA-3D printing model.The values of ICC were all greater than 0.950;the maximum values of absolute / relative errors were-0.58 mm and-1.37％,respectively;the maximum 3D error of prosthesis model was 0.237 mm,and the average value was 0.132 mm.Conclusion:The CT data of SLA-3D model is highly consistent with the original data,and it is accurate and reliable in the diagnosis and treatment of the diseases in orthopedics and maxillofacial surgery.