| Objective: To investigate the feasibility and stability of measuring the bone mineral density of proximal femur by using GSI.The bone mineral density distribution of proximal femur was demonstrated by using EFI,providing guidance for the diagnosis and treatment of osteoporosis and the surgical treatment of brittle fracture.Methods: 1.Place the special calibration body film at the same scanning position and in the same external scanning environment(in the air),and scan it with the mode of energy spectrum of GSI.The scanning voltage is 140/80 kV and 275 mA,the layer thickness is0.625 mm,the interval is 0.625 mm,the tube spacing is 1.375:1,and the rotation time is0.8s.With 10 times of scanning(at different time point which is near to each other),the original image was reconstructed into calcium density image through the image post-processing workstation of Advantage Windows4.5.Then respectively upload the original scan image and the calcium density reconstruction image to Amira6.01 software.The calcium density and gray value of four calibrated cylinders in the body film were measured for 10 times,so that to analyze the stability of measuring the density of the body film by GSI.2.Under the same external conditions,the bulb current was 440 mA,360 mA,375 mA,280 mA and 275 mA,respectively.The calibration body film was scanned,and the calcium density value and gray value of the body film were measured for 10 times.3.The external scanning environmental condition was changed,and the calibration body film was placed in a square water tank.The scanning voltage was set at 140/80 kv with the bulb current at 375 mA and 275 mA respectively.The measurement was carried out according to experimental method 2.The stability of measuring the body film density by using GSI is visualized in SPSS20.0 software analysis variance,and the relationship between the body film density,calcium density value and gray value was analyzed by linear regression.4.The energy spectrum mode of GSI was used to scan the proximal femur of a healthy woman of 60.The scanning voltage was 140/80 kV,with instantaneous switching,the tube current was 375 mA,the layer thickness was 1.25 mm,the interval was 1.25 mm,the tube spacing was 1.375:1,and the rotation time was 0.8s.The original scanned image and the reconstructed calcium density image were imported into Mimics 20.0 software in a common DICOM standard format for three-dimensional reconstruction of the proximal femur.After the reconstruction,the images were imported into 3-matic to mesh and build 3D data models.Then the models are returned to Mimics 20.0 for material property assignment,and the relationship between calcium value,gray value and bone density is set,and the in-situ assignment process based on CT image is completed.Then the assigned model was imported into ANSYS software to visually display the bone density distribution map of proximal femur.Then the model after assignment is imported into ANSYS software to visualize the bone density distribution map of the proximal femur.Results: 1.Under different scanning condition of GSI and different external environments,the values of calcium and gray scale were in good consistency,showing a positive linear correlation with the bone mineral density of the body film calibration(P< 0.05).The regression equation of calcium density value and body film density is y=0.395x-35.22,and the regression equation of gray scale value and body film density was y =0.983 x + 22.89.It indicates that GSI can be used to measure bone density,and which has good stability.2.Energy spectrum technology of GSI combined with FEI can show the bone density distribution map of proximal femur volume.The bone density distribution map based on calcium density value is clearer and more reliable.Conclusions: It is feasible and stable to measure the bone mineral density of proximal femur by using GSI.Also,the EFI can be used to visualize the bone mineral density distribution of proximal femur,which provides guides for the diagnosis and treatment of osteoporosis. |
PDF Full Text Request