目的:获得钩骨内微小动脉三维构筑模型,为钩骨骨折后血供保护提供解剖学基础。方法:将红色氧化铅研磨至40μm以下,按铅丹和松节油1 g∶1.5 m L、1 g∶1 m L和1 g∶0.5 m L比例混匀制成铅造影剂。3个新鲜上肢肱动脉插管,灌注铅造影剂。...目的:获得钩骨内微小动脉三维构筑模型,为钩骨骨折后血供保护提供解剖学基础。方法:将红色氧化铅研磨至40μm以下,按铅丹和松节油1 g∶1.5 m L、1 g∶1 m L和1 g∶0.5 m L比例混匀制成铅造影剂。3个新鲜上肢肱动脉插管,灌注铅造影剂。钩骨取材,使用micro CT扫描钩骨,扫描设置为Binning 1,系统分辨率为highmed,重建设置为Down sample factor 2,图像最终分辨率为27.30μm。最终获得钩骨周围与钩骨内血管在各个切面的图像,重建形成钩骨内微动脉分支分布的三维构筑。结果:钩骨表面血管分布密集,主要分布在钩骨周围的韧带和肌腱内。钩骨表面主要有4大血管分布区域,分别位于钩骨体掌侧平台、钩骨背侧、钩骨尺侧和钩骨钩顶端。钩骨钩接受了来自钩骨钩顶端、钩骨体掌侧平台和钩骨尺侧动脉网的骨内分支,钩骨体接收了钩骨掌侧平台、钩骨背侧和钩骨尺侧的动脉骨内分支,并且骨内动脉相互吻合。结论:钩骨体和钩骨钩的骨内微小动脉各自存在多个来源并有丰富的吻合,出现缺血性钩骨坏死的概率较小,钩骨钩骨折后骨折不愈可能是由于对线不良等其他原因造成的。展开更多
X-ray micro-computed tomography(μ-CT)can be used to provide both qualitative and quantitative information on the structure of three-dimensional(3D)bioactive scaffolds.When performed in a dry state,μ-CT accurately re...X-ray micro-computed tomography(μ-CT)can be used to provide both qualitative and quantitative information on the structure of three-dimensional(3D)bioactive scaffolds.When performed in a dry state,μ-CT accurately reflects the structure of collagen-based scaffolds,but imaging in a wet state offers challenges with radiolucency.Here we have used phosphotungstic acid(PTA)as a contrast agent to visualise fully hydrated collagen scaffolds in a physiologically relevant environment.A systematic investigation was performed to understand the effects of PTA on the results of μ-CT imaging by varying sample processing variables such as crosslinking density,hydration medium and staining duration.Immersing samples in 0.3% PTA solution overnight completely stained the samples and the treatment provided a successful route forμ-CT analysis of crosslinked samples.However,significant structural artefacts were observed for samples which were either non-crosslinked or had low levels of crosslinking,which had a heterogeneous interior architecture with collapsed pores at the scaffold periphery.This work highlights the importance of optimising the choice of processing and staining conditions to ensure accurate visualisation for hydrated 3D collagen scaffolds in an aqueous medium.展开更多
Trabecular bone is natural material with heterogeneous tissue properties.The effect of tissue heterogeneity on the micromechanical behavior of trabecular bone is commonly evaluated by microCT-based finite element(micr...Trabecular bone is natural material with heterogeneous tissue properties.The effect of tissue heterogeneity on the micromechanical behavior of trabecular bone is commonly evaluated by microCT-based finite element(microFE)analysis.Results from prior work remain inconclusive and lack of experimental validation.To address these issues,we combined microFE analysis with mechanical testing and microCT-based digital volume correlation(DVC),as a validation for the microFE approach.Porcine trabecular specimens were tested in compression as sequential microCT scans were taken.DVC was performed to extract“realistic”boundary conditions that were applied to microFE models,and to measure microstructural deformation and strain of the trabecular specimens.Heterogeneous and homogeneous microFE models of each trabecular specimen were created and compared with the experimentally measured microstructural displacement and strains.Results showed strong correlations between DVC-measured and microFE-predicted trabecular displacement and strain fields(R^(2)>0.9,p<0.05),regardless of heterogeneous or homogeneous material assignments.The heterogeneous and homogeneous models predicted similar magnitudes for maximum or minimum principal strains(R^(2)=1,p<0.05).However,incorporation of tissue heterogeneity decreased more than 16.5%in the overall stress level of the trabecular tissues.Regardless,very strong correlations were found between the heterogeneous and homogeneous model-predicted principal strains or stresses.These results together suggest that tissue heterogeneity may have little effect on microFE modeling of typical elastic displacement and strains in the trabecular bone,suggesting that homogeneous material models might be sufficient to predict general trabecular micromechanics.展开更多
文摘目的:获得钩骨内微小动脉三维构筑模型,为钩骨骨折后血供保护提供解剖学基础。方法:将红色氧化铅研磨至40μm以下,按铅丹和松节油1 g∶1.5 m L、1 g∶1 m L和1 g∶0.5 m L比例混匀制成铅造影剂。3个新鲜上肢肱动脉插管,灌注铅造影剂。钩骨取材,使用micro CT扫描钩骨,扫描设置为Binning 1,系统分辨率为highmed,重建设置为Down sample factor 2,图像最终分辨率为27.30μm。最终获得钩骨周围与钩骨内血管在各个切面的图像,重建形成钩骨内微动脉分支分布的三维构筑。结果:钩骨表面血管分布密集,主要分布在钩骨周围的韧带和肌腱内。钩骨表面主要有4大血管分布区域,分别位于钩骨体掌侧平台、钩骨背侧、钩骨尺侧和钩骨钩顶端。钩骨钩接受了来自钩骨钩顶端、钩骨体掌侧平台和钩骨尺侧动脉网的骨内分支,钩骨体接收了钩骨掌侧平台、钩骨背侧和钩骨尺侧的动脉骨内分支,并且骨内动脉相互吻合。结论:钩骨体和钩骨钩的骨内微小动脉各自存在多个来源并有丰富的吻合,出现缺血性钩骨坏死的概率较小,钩骨钩骨折后骨折不愈可能是由于对线不良等其他原因造成的。
基金supported by Engineering and Physical Sciences Research Council(EP/N019938/1).
文摘X-ray micro-computed tomography(μ-CT)can be used to provide both qualitative and quantitative information on the structure of three-dimensional(3D)bioactive scaffolds.When performed in a dry state,μ-CT accurately reflects the structure of collagen-based scaffolds,but imaging in a wet state offers challenges with radiolucency.Here we have used phosphotungstic acid(PTA)as a contrast agent to visualise fully hydrated collagen scaffolds in a physiologically relevant environment.A systematic investigation was performed to understand the effects of PTA on the results of μ-CT imaging by varying sample processing variables such as crosslinking density,hydration medium and staining duration.Immersing samples in 0.3% PTA solution overnight completely stained the samples and the treatment provided a successful route forμ-CT analysis of crosslinked samples.However,significant structural artefacts were observed for samples which were either non-crosslinked or had low levels of crosslinking,which had a heterogeneous interior architecture with collapsed pores at the scaffold periphery.This work highlights the importance of optimising the choice of processing and staining conditions to ensure accurate visualisation for hydrated 3D collagen scaffolds in an aqueous medium.
基金This work was supported by National Natural Science Foundation of China[grant numbers 11702008,11832003]Beijing Natural Science Foundation of China[grant numbers 7202003]Beijing Municipal Education Commission Research Program[grant numbers KM202010005035].
文摘Trabecular bone is natural material with heterogeneous tissue properties.The effect of tissue heterogeneity on the micromechanical behavior of trabecular bone is commonly evaluated by microCT-based finite element(microFE)analysis.Results from prior work remain inconclusive and lack of experimental validation.To address these issues,we combined microFE analysis with mechanical testing and microCT-based digital volume correlation(DVC),as a validation for the microFE approach.Porcine trabecular specimens were tested in compression as sequential microCT scans were taken.DVC was performed to extract“realistic”boundary conditions that were applied to microFE models,and to measure microstructural deformation and strain of the trabecular specimens.Heterogeneous and homogeneous microFE models of each trabecular specimen were created and compared with the experimentally measured microstructural displacement and strains.Results showed strong correlations between DVC-measured and microFE-predicted trabecular displacement and strain fields(R^(2)>0.9,p<0.05),regardless of heterogeneous or homogeneous material assignments.The heterogeneous and homogeneous models predicted similar magnitudes for maximum or minimum principal strains(R^(2)=1,p<0.05).However,incorporation of tissue heterogeneity decreased more than 16.5%in the overall stress level of the trabecular tissues.Regardless,very strong correlations were found between the heterogeneous and homogeneous model-predicted principal strains or stresses.These results together suggest that tissue heterogeneity may have little effect on microFE modeling of typical elastic displacement and strains in the trabecular bone,suggesting that homogeneous material models might be sufficient to predict general trabecular micromechanics.
