Large-scale osteocyte lacunar morphological analysis of transiliac bone in normal and osteoporotic premenopausal women

Bone's adaptation ability is governed by the network of embedded osteocytes that inhabit individual crevasses called lacunae. The morphology of these lacunae and their resident osteocytes are known to change with age and diseases such as postmenopausal osteoporosis. However, it is unclear whether alterations in lacunar morphology are present in younger populations with osteoporosis. To investigate this, we implemented a previously validated methodology to image and quantify the three-dimensional morphometries of lacunae on a large scale (26.2 million cells) with ultra-high-resolution micro-computed tomography (microCT) in transiliac bone biopsies from three groups of premenopausal women: control n=39; idiopathic osteoporosis (IOP) n=45; idiopathic low BMD (ILBMD) n=19. Important lacunar morphometric parameters were measured in both trabecular and cortical bone: lacunar density (Lc.N/BV), lacunar porosity (Lc.TV/BV), lacunar number (Lc.N), lacunar volume (Lc.V), lacunar surface area (Lc.S), lacunar alignment (Lc.θ), lacunar stretch (Lc.St), lacunar oblateness (Lc.Ob), lacunar equancy (Lc.Eq), and lacunar sphericity (Lc.Sr). These were then compared against each other and also with previously measured tissue morphometries including: bone volume density (BV/TV), trabecular separation (Tb.Sp), trabecular number (Tb.N), and trabecular thickness (Tb.Th), structure model index (SMI), cortical porosity (Ct.Po) and cortical pore spacing (Ct.Sp). We detected no differences in lacunar morphology between the IOP, ILBMD and healthy premenopausal women. In contrast, we did find significant differences between lacunar morphologies in cortical and trabecular regions within all three groups, which was consistent with our previous findings on a subgroup of the healthy group. Furthermore, we discovered strong correlations between Lc.Sr from both trabecular and cortical regions with the measured BV/TV. The findings and comprehensive lacunar dataset we present here will be a crucial foundation for future investigations of the relationship between osteocyte lacunar morphology and disease.

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Large-scale quantification of human osteocyte lacunar morphological biomarkers as assessed by ultra-high-resolution desktop micro-computed tomography

Bone ◽

10.1016/j.bone.2021.116094 ◽

2021 ◽

pp. 116094

Author(s):

Elliott Goff ◽

Federica Buccino ◽

Chiara Bregoli ◽

Jonathan P. McKinley ◽

Basil Aeppli ◽

...

Keyword(s):

Computed Tomography ◽

High Resolution ◽

Large Scale ◽

Micro Computed Tomography ◽

Osteocyte Lacunar

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Novel magnetic resonance technique for characterizing mesoscale structure of trabecular bone

Royal Society Open Science ◽

10.1098/rsos.180563 ◽

2018 ◽

Vol 5 (8) ◽

pp. 180563 ◽

Cited By ~ 2

Author(s):

Chantal Nguyen ◽

Kimberly J. Schlesinger ◽

Timothy W. James ◽

Kristin M. James ◽

Robert L. Sah ◽

...

Keyword(s):

Magnetic Resonance ◽

Trabecular Bone ◽

Structural Information ◽

Three Dimensional ◽

Biological Tissues ◽

Bone Fragility ◽

Support Vector ◽

Osteoporotic Bone ◽

Micro Computed Tomography ◽

Trabecular Thickness

Osteoporosis, characterized by increased fracture risk and bone fragility, impacts millions of adults worldwide, but effective, non-invasive and easily accessible diagnostic tests of the disease remain elusive. We present a magnetic resonance (MR) technique that overcomes the motion limitations of traditional MR imaging to acquire high-resolution frequency-domain data to characterize the texture of biological tissues. This technique does not involve obtaining full two-dimensional or three-dimensional images, but can probe scales down to the order of 40 μm and in particular uncover structural information in trabecular bone. Using micro-computed tomography data of vertebral trabecular bone, we computationally validate this MR technique by simulating MR measurements of a ‘ratio metric’ determined from a few k -space values corresponding to trabecular thickness and spacing. We train a support vector machine classifier on ratio metric values determined from healthy and simulated osteoporotic bone data, which we use to accurately classify osteoporotic bone.

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Model-Independent 3D Descriptors of Vertebral Cancellous Bone Architecture

Journal of Osteoporosis ◽

10.4061/2010/641578 ◽

2010 ◽

Vol 2010 ◽

pp. 1-6 ◽

Cited By ~ 3

Author(s):

Ian H. Parkinson ◽

Danielle Forbes ◽

Peter Sutton-Smith ◽

Nicola L. Fazzalari

Keyword(s):

Cancellous Bone ◽

Structural Model ◽

Explanatory Power ◽

Volume Density ◽

Bone Volume ◽

Bone Architecture ◽

Micro Computed Tomography ◽

Trabecular Thickness ◽

Trabecular Separation ◽

Structural Model Index

High-resolution micro computed tomography has enabled measurement of bone architecture derived from 3D representations of cancellous bone. Twenty-eight vertebral bodies were obtained from four embalmed male cadavers. From 3D anaglyphs, trabecular rod thickness and length were measured and the trabecular rod Buckling index was calculated. From 3D voxel-based datasets, bone volume density, trabecular thickness, and trabecular separation were measured. Also, trabecular bone pattern factor, structural model index, connectivity density, and degree of anisotropy were calculated. Bone volume density alone explains 59% of the variability in trabecular rod Buckling index. The addition of connectivity density, trabecular separation, and structural model index, in a multiple regression statistical model, improves the explanatory power to 77%. The relationships between measures of cancellous bone architecture and a derived measure of trabecular rod strength were investigated. Morphological descriptors of cancellous bone provide a composite explanatory model of trabecular rod strength.

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Reduced local mechanical stimuli in spaceflight diminishes osteocyte lacunar morphometry and spatial heterogeneity in mouse cortical bone

10.1101/2022.01.04.474962 ◽

2022 ◽

Author(s):

Jennifer C. Coulombe ◽

Zachary K. Mullen ◽

Ashton M. Wiens ◽

Liam E. Fisher ◽

Maureen E. Lynch ◽

...

Keyword(s):

Cortical Bone ◽

Measurement Errors ◽

Space Shuttle ◽

Three Dimensional ◽

Large Cell ◽

Young Female ◽

Mechanical Stimuli ◽

Micro Computed Tomography ◽

Osteocyte Lacunae ◽

Osteocyte Lacunar

Three-dimensional (3D) imaging of osteocyte lacunae has recently substantiated the connection between lacunar shape and size, and osteocyte age, viability, and mechanotransduction. Yet it remains unclear why individual osteocytes reshape their lacunae and how networks of osteocytes change in response to local alterations in mechanical loads. We evaluated the effects of local mechanical stimuli on osteocyte lacunar morphometrics in tibial cortical bone from young female mice flown on the Space Shuttle for ~13 days. We optimized scan parameters, using a laboratory-based submicrometer-resolution X-Ray Microscope, to achieve large ~ 0.3 mm3 fields of view with sufficient resolution (≥ 0.3 μm) to visualize and measure thousands of lacunae per scan. Our novel approach avoids large measurement errors that are inherent in 2D and enables a facile 3D solution as compared to the lower resolution from benchtop micro-computed tomography (CT) systems or the cost and inaccessibility of synchrotron-based CT. Osteocyte lacunae were altered following microgravity exposure in a region-specific manner: more elongated (+7.0% Stretch) in predominately tensile-loaded bone as compared to those in compressively-loaded regions. In compressively-loaded bone, lacunae formed in microgravity were significantly larger (+6.9% Volume) than in the same region formed on Earth. We also evaluated lacunar heterogeneity (i.e., spatial autocorrelation of lacunar morphometric parameters) via kriging models. These statistical models demonstrated that heterogeneity varied with underlying spatial contributors, i.e. the local mechanical and biological environment. Yet in the absence of gravitational loading, osteocyte lacunae in newly formed bone were larger and were collectively more homogenous than in bone formed on Earth. Overall, this study shows that osteocyte reshape their lacunae in response to changes, or absence, in local mechanical stimuli and different biological environments. Additionally, spatial relationships among osteocytes are complex and necessitate evaluation in carefully selected regions of interest and of large cell populations.

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Large-scale quantification of human osteocyte lacunar morphological biomarkers as assessed by ultra-high-resolution desktop micro-computed tomography

10.1101/2021.01.05.425223 ◽

2021 ◽

Author(s):

Elliott Goff ◽

Federica Buccino ◽

Chiara Bregoli ◽

Jonathan P. McKinley ◽

Basil Aeppli ◽

...

Keyword(s):

Computed Tomography ◽

High Resolution ◽

Surface Area ◽

High Throughput ◽

Large Scale ◽

Micro Ct ◽

Micro Computed Tomography ◽

Osteocyte Lacunae ◽

Bone Biopsies ◽

Positive Rate

ABSTRACTUltra-high-resolution imaging of the osteocyte lacuno-canalicular network (LCN) three-dimensionally (3D) in a high-throughput fashion has greatly improved the morphological knowledge about the constituent structures – positioning them as potential biomarkers. Technologies such as serial focused ion beam/scanning electron microscopy (FIB/SEM) and confocal scanning laser microscopy (CLSM) can image in extremely high resolution, yet only capture a small number of lacunae. Synchrotron radiation computed tomography (SR-CT) can image with both high resolution and high throughput but has a limited availability. Desktop micro-computed tomography (micro-CT) provides an attractive balance: high-throughput imaging on the micron level without the restrictions of SR-CT availability. Over the past decade, desktop micro-CT has been used to image osteocyte lacunae in a variety of animals, yet few studies have employed it to image human lacunae using clinical biopsies.In this study, accuracy, precision, and sensitivity of large-scale quantification of human osteocyte lacunar morphometries were assessed by ultra-high-resolution desktop micro-computed tomography. For this purpose, thirty-one transiliac human bone biopsies containing trabecular and cortical regions were imaged using ultra-high-resolution desktop micro-CT at a nominal isotropic voxel resolution of 1.2µm. The resulting 3D images were segmented, component labeled, and the following morphometric parameters of 7.71 million lacunae were measured: Lacunar number (Lc.N), density (Lc.N/BV), porosity (Lc.TV/BV), volume (Lc.V), surface area (Lc.S), surface area to volume ratio (Lc.S/Lc.V), stretch (Lc.St), oblateness (Lc.Ob), sphericity (Lc.Sr), equancy (Lc.Eq), and angle (Lc.θ).Accuracy was quantified by comparing automated lacunar segmentation to manual segmentation. Mean true positive rate (TPR), false positive rate (FPR), and false negative rate (FNR) were 89.0%, 3.4%, and 11.0%, respectively. Regarding the reproducibility of lacunar morphometry from repeated measurements, precision errors were low (0.2 – 3.0%) and intraclass correlation coefficients were high (0.960 – 0.999). Significant differences between cortical and trabecular regions (p<0.001) existed for Lc.N/BV, Lc.TV/BV, local lacunar surface area (<Lc.S>), and local lacunar volume (<Lc.V>), all of which demonstrate the sensitivity of the method and are possible biomarker candidates. This study provides the rigorous foundation required for future large-scale morphometric studies using ultra-high-resolution desktop micro-CT and high-throughput analysis of millions of osteocyte lacunae in human bone samples. Furthermore, the validation of this technology for imaging of human lacunar properties establishes the quality and reliability required for the accurate, precise, and sensitive assessment of osteocyte morphometry in clinical bone biopsies.

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Broad application of non-invasive imaging techniques to echinoids and other echinoderm taxa*

Zoosymposia ◽

10.11646/zoosymposia.7.1.6 ◽

2012 ◽

Vol 7 (1) ◽

pp. 53-70 ◽

Cited By ~ 19

Author(s):

ALEXANDER ZIEGLER

Keyword(s):

Sea Urchin ◽

Large Scale ◽

Sea Urchins ◽

Imaging Techniques ◽

Three Dimensional ◽

Image Data ◽

Micro Computed Tomography ◽

Non Invasive ◽

Mri Scans ◽

Three Dimensional Models

Tomographic imaging techniques such as micro-computed tomography (μCT) and magnetic resonance imaging (MRI) permit the gathering of digital anatomical data from whole animal specimens non-invasively. The resulting datasets can be used for direct observation of the two-dimensional tomographic image data as well as for manual and semi-automated three-dimensional modelling. Freshly fixed specimens as well as preserved museum material can be successfully analyzed using this approach, giving the zoomorphologist a powerful tool for large-scale comparative studies. In order to demonstrate the principle suitability of non-invasive imaging in echinoderm research, μCT scans of 199 and MRI scans of 92 sea urchin (Echinodermata: Echinoidea) species were acquired, resulting in a total of 203 analyzed echinoid species. The taxa selected represent 50 of the currently recognized 60 extant sea urchin families. The present article lists all species that have been analyzed so far and provides information about the scanning parameters employed for each dataset. Furthermore, the workflow established to generate three-dimensional models of sea urchins is outlined. Using a number of examples from μCT as well as MRI scans performed on echinoids, the potential of the systematic approach described here is highlighted. Finally, the suitability of non-invasive imaging techniques for the study of other echinoderm taxa is assessed based on multimodal datasets of representative species.

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On the semiannual formation of large scale three‐dimensional vortices at the stratopause

Geophysical Research Letters ◽

10.1029/2020gl090072 ◽

2020 ◽

Author(s):

Terence J. O'Kane ◽

Vassili Kitsios ◽

Mark A. Collier

Keyword(s):

Large Scale ◽

Three Dimensional

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Micro-Computed Tomography Analysis of Subchondral Bone Regeneration Using Osteochondral Scaffolds in an Ovine Condyle Model

Applied Sciences ◽

10.3390/app11030891 ◽

2021 ◽

Vol 11 (3) ◽

pp. 891

Author(s):

Taylor Flaherty ◽

Maryam Tamaddon ◽

Chaozong Liu

Keyword(s):

Computed Tomography ◽

Bone Regeneration ◽

Subchondral Bone ◽

Volume Ratio ◽

Bone Volume ◽

Osteochondral Defects ◽

Micro Ct ◽

Micro Computed Tomography ◽

Trabecular Thickness ◽

Osteochondral Scaffold

Osteochondral scaffold technology has emerged as a promising therapy for repairing osteochondral defects. Recent research suggests that seeding osteochondral scaffolds with bone marrow concentrate (BMC) may enhance tissue regeneration. To examine this hypothesis, this study examined subchondral bone regeneration in scaffolds with and without BMC. Ovine stifle condyle models were used for the in vivo study. Two scaffold systems (8 mm diameter and 10 mm thick) with and without BMC were implanted into the femoral condyle, and the tissues were retrieved after six months. The retrieved femoral condyles (with scaffold in) were examined using micro-computed tomography scans (micro-CT), and the micro-CT data were further analysed by ImageJ with respect to trabecular thickness, bone volume to total volume ratio (BV/TV) ratio, and degree of anisotropy of bone. Statistical analysis compared bone regeneration between scaffold groups and sub-set regions. These results were mostly insignificant (p < 0.05), with the exception of bone volume to total volume ratio when comparing scaffold composition and sub-set region. Additional trends in the data were observed. These results suggest that the scaffold composition and addition of BMC did not significantly affect bone regeneration in osteochondral defects after six months. However, this research provides data which may guide the development of future treatments.

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A Review on Additive Manufacturing Possibilities for Electrical Machines

Energies ◽

10.3390/en14071940 ◽

2021 ◽

Vol 14 (7) ◽

pp. 1940

Author(s):

Muhammad Usman Naseer ◽

Ants Kallaste ◽

Bilal Asad ◽

Toomas Vaimann ◽

Anton Rassõlkin

Keyword(s):

Additive Manufacturing ◽

Large Scale ◽

Three Dimensional ◽

Electrical Machines ◽

Electromagnetic Properties ◽

Scale Production ◽

Performance Parameters ◽

Large Scale Production ◽

One Step ◽

Manufacturing Techniques

This paper presents current research trends and prospects of utilizing additive manufacturing (AM) techniques to manufacture electrical machines. Modern-day machine applications require extraordinary performance parameters such as high power-density, integrated functionalities, improved thermal, mechanical & electromagnetic properties. AM offers a higher degree of design flexibility to achieve these performance parameters, which is impossible to realize through conventional manufacturing techniques. AM has a lot to offer in every aspect of machine fabrication, such that from size/weight reduction to the realization of complex geometric designs. However, some practical limitations of existing AM techniques restrict their utilization in large scale production industry. The introduction of three-dimensional asymmetry in machine design is an aspect that can be exploited most with the prevalent level of research in AM. In order to take one step further towards the enablement of large-scale production of AM-built electrical machines, this paper also discusses some machine types which can best utilize existing developments in the field of AM.

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Vibration characteristics of triple-gear-rotor system in compressed air energy storage under variable torque load

Science Progress ◽

10.1177/0036850420987058 ◽

2021 ◽

Vol 104 (1) ◽

pp. 003685042098705

Author(s):

Xinran Wang ◽

Yangli Zhu ◽

Wen Li ◽

Dongxu Hu ◽

Xuehui Zhang ◽

...

Keyword(s):

Large Scale ◽

Three Dimensional ◽

Element Model ◽

Rotor System ◽

Dynamic Responses ◽

System Response ◽

Rotating Speed ◽

Torque Load ◽

Set Up ◽

Two Stages

This paper focuses on the effects of the off-design operation of CAES on the dynamic characteristics of the triple-gear-rotor system. A finite element model of the system is set up with unbalanced excitations, torque load excitations, and backlash which lead to variations of tooth contact status. An experiment is carried out to verify the accuracy of the mathematical model. The results show that when the system is subjected to large-scale torque load lifting at a high rotating speed, it has two stages of relatively strong periodicity when the torque load is light, and of chaotic when the torque load is heavy, with the transition between the two states being relatively quick and violent. The analysis of the three-dimensional acceleration spectrum and the meshing force shows that the variation in the meshing state and the fluctuation of the meshing force is the basic reasons for the variation in the system response with the torque load. In addition, the three rotors in the triple-gear-rotor system studied show a strong similarity in the meshing states and meshing force fluctuations, which result in the similarity in the dynamic responses of the three rotors.

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