Chinese Journal of Tissue Engineering Research ›› 2021, Vol. 25 ›› Issue (6): 912-916.doi: 10.3969/j.issn.2095-4344.2397

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Accuracy of target bone segments in personalized differential modeling and simulation of CT scanning parameters at fracture end

Yuan Xinping1, Shao Yanbo1, Wu Chao1, Wang Jianling2, Tong Liangcheng2, Li Ying2, 3   

  1. 1Department of Radiology, 2Department of Orthopedics, Air Force Hospital of Eastern Theater Command of Chinese PLA, Nanjing 210002, Jiangsu Province, China; 3Anhui Medical University, Hefei 230032, Anhui Province, China
  • Received:2020-05-06 Revised:2020-05-12 Accepted:2020-06-17 Online:2021-02-28 Published:2020-12-04
  • Contact: Li Ying, MD, Associate chief physician, Department of Orthopedics, Air Force Hospital of Eastern Theater Command of Chinese PLA, Nanjing 210002, Jiangsu Province, China; Anhui Medical University, Hefei 230032, Anhui Province, China
  • About author:Yuan Xinping, Master, Associate chief physician, Department of Radiology, Air Force Hospital of Eastern Theater Command of Chinese PLA, Nanjing 210002, Jiangsu Province, China
  • Supported by:
    the Nanjing Military Region Medical Science and Technology Innovation Project, No. 15DX012; the Nanjing Medical Science and Technology Development Project, No. 201503008

Abstract: BACKGROUND: CT scan and differential modeling are used to analyze the fracture end, which is an effective method to judge the degree of bone healing. To obtain the high precision of differential modeling and simulation, how to select the optimal CT scanning parameters needs further research and analysis. 
OBJECTIVE: To compare the effects of different CT scanning parameters on modeling accuracy in personalized differential modeling analysis, to verify the accuracy and effectiveness of personalized differential modeling in the reduction of simulated target bone segments, and to explore the research value of this method in judging the degree of bone healing of long canals of lower extremities.
METHODS: The model of internal fixation was established with porcine femur. Four groups of 80 kV-300 mA (group A-low dose), 120 kV-335 mA (group B-automatic tube current control system), 140 kV-300 mA (group C-manual setting comparison) and 140 kV-80 mA (group D-high kV and low mA) were used to scan the same object with the same pitch, slice thickness and environment. The scanning data of each group were selected, the same CT value range was used, and the differential modeling analysis method was used to model the target bone segment. The average area and maximum area of metal artifacts in CT scanning images, the average CT value, volume and maximum wall thickness peak after differential modeling analysis, the radiation amount under four groups of scanning conditions were compared to determine the reduction of metal artifacts, modeling accuracy and radiation, so as to select the optimal CT scanning parameters.  
RESULTS AND CONCLUSION: (1) Artifact measurement method results: In group A, there were many metal artifacts, which obviously obstructed bone tissue, and had a possibility of missed diagnosis. In group D, there were minimal metal artifacts, less occlusion around bone tissue, but poor image contrast and high fog. The difference between group B and group C lay in the clarity of images, and the accuracy of diagnosis was basically the same. Therefore, the order of artifact size was as follows: group A > group B > group C > Group D. (2) Differential modeling analysis results: In group B, because of the smaller artifact and less loss of CT value, the simulated model was more close to the reality. Moreover, group B adopted the automatic tube current control system, which could obviously show that the radiation amount was smaller and more protective for patients. (3) It is confirmed that the CT scan under the condition of group B can effectively reduce the interference caused by metal artifacts, better retain the original information of CT gray value, and retain the density information of the target bone segment to the maximum extent. Therefore, when establishing differential modeling, the CT automatic tube current control system is used as the optimal CT scanning parameter, which not only improves the simulation accuracy of personalized differential modeling, but also increases the accuracy of calculation.

Key words: bone healing, nonunion, lower limb long bone, metal artifact, CT value, differential modeling, internal fixation

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