Effects of Scan Resolutions and Element Sizes on Bovine Vertebral Mechanical Parameters from Quantitative Computed Tomography-Based Finite Element Analysis.

Min Zhang,Xu Huang,He Gong,Meng Zhang,Bei Liu,Jiazi Gao

doi:10.1155/2017/5707568

Min Zhang, Xu Huang + Show 4 more

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https://doi.org/10.1155/2017/5707568

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Abstract

Quantitative computed tomography-based finite element analysis (QCT/FEA) has been developed to predict vertebral strength. However, QCT/FEA models may be different with scan resolutions and element sizes. The aim of this study was to explore the effects of scan resolutions and element sizes on QCT/FEA outcomes. Nine bovine vertebral bodies were scanned using the clinical CT scanner and reconstructed from datasets with the two-slice thickness, that is, 0.6 mm (PA resolution) and 1 mm (PB resolution). There were significantly linear correlations between the predicted and measured principal strains (R2 > 0.7, P < 0.0001), and the predicted vertebral strength and stiffness were modestly correlated with the experimental values (R2 > 0.6, P < 0.05). Two different resolutions and six different element sizes were combined in pairs, and finite element (FE) models of bovine vertebral cancellous bones in the 12 cases were obtained. It showed that the mechanical parameters of FE models with the PB resolution were similar to those with the PA resolution. The computational accuracy of FE models with the element sizes of 0.41 × 0.41 × 0.6 mm3 and 0.41 × 0.41 × 1 mm3 was higher by comparing the apparent elastic modulus and yield strength. Therefore, scan resolution and element size should be chosen optimally to improve the accuracy of QCT/FEA.

Highlights

Osteoporosis (OP) is a common disease in aging population characterized by reduced bone mass and compromised bone strength
With the development of computer technology and biomechanics, quantitative computed tomography-based finite element analysis (QCT/FEA) is a promising tool for assessing strength and stiffness because it can take into account accurate vertebral geometry, architecture, and the heterogeneous distribution of bone material properties according to greyscale values in images [6, 7]
The linear regression equations and the correlation coefficients of nine bovine vertebral bodies were summarized in Table 1, in which εPA με represents the principal strains predicted from QCT/FEA models with the PA resolution, εPB με represents the principal strains predicted from QCT/FEA models with the PB resolution, and εE με represents the principal strains measured in compressive mechanical testing

Summary

Introduction

Osteoporosis (OP) is a common disease in aging population characterized by reduced bone mass and compromised bone strength. Dual-energy radiograph absorptiometry (DXA) is widely used to measure bone mineral density (BMD) in clinics, which represents bone strength to assess the risk of OP and fracture. It was shown that DXAmeasured BMD accounts for only 50%–70% of the variation in lumbar vertebral body strength [4, 5]. With the development of computer technology and biomechanics, quantitative computed tomography-based finite element analysis (QCT/FEA) is a promising tool for assessing strength and stiffness because it can take into account accurate vertebral geometry, architecture, and the heterogeneous distribution of bone material properties according to greyscale values in images [6, 7]. QCT/FEA is more accurate than quantitative computed tomography- (QCT-) measured BMD for strength assessment in clinics [7]

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