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.
ABSTRACT
Objective; To screen the genes may be regulated by NOB1 by using gene microarray technique, and to clarify the regulatory effect of NOB1 on the expression of osteosarcoma cell-related genes. Methods: The U20S cells were treated with lentivirus-mediated RNA interference and to establish the osteosarcoma cells Lv-shN0Bl-U20S. Lv-shCon-U20S group and Lv-shN0Bl-U20S group were set up. The mRNA expressions of those cells were detected using expression pattern analysis. Gene Oncology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to predict the global functions of NOB1, including biological processes, cellular components, molecular functions, and signaling pathways. Results; After NOB1 interference in the U20S cells, there were 792 genes with up-regulated mRNA expression level and 1 059 genes with down-regulated mRNA expression level, with a total variation of 1 851 genes. The GO analysis results showed that from the enrichment degree of cell location entries, the differentially encoded product proteins were mainly distributed on the cell membrane as 56. 9% of the total difference genes, 39. 4% of the totally differential genes distributed in the extracellular region, and 20% of the totally differential genes in the extracellular space; from the enrichment degrees of the molecular function items, the main function of the differentially encoded product proteins was calciu mion binding-related function (22% of the totally differential genes), the second function was transporter activity (9. 2% of the totally differenital genes), and the third function was actin binding activity (8. 7% of the totally differential genes). In terms of the enrichment of biochemical process entries, the main participation process of differentially encoded product proteins was 18. 7% of the totally differential genes of signal transduction, the second involved process was 15. 6% of the totally differential genes produced by multiple organelles, and the third process was the cell adhesion process accounted for 10. 2% of the totally differential genes. The KEGG analysis results showed that their encoding proteins were involved in plasma membrane, calcium ion binding activity and signal transduction. Conclusion; Knockout of NOB1 can affect the expressions of osteosarcoma cell-related genes in an all-round way.