In Vivo Analysis of Trabecular Bone Architecture (original) (raw)
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Suitability of texture features to assess changes in trabecular bone architecture
2002
The purpose of this study was to determine the ability of texture features to assess changes in trabecular bone architecture as projected in radiographs. Micro-CT datasets of trabecular bone were processed to simulate different changes in architecture. Radiographs were simulated by projecting the 3D-bone structure. Texture features, based on mathematical morphology, determined on the simulated radiographs were able to detect structural changes in the trabecular bone.
Current Medicinal Chemistry, 2011
1 0 9 2 9 -8 6 7 3 / 1 1 $ 5 8 . 0 0 + . 0 0 © 2 0 1 1 B e n t h a m S c i e n c e P u b l i s h e r s L t d . Abstract: We apply noval techniques, the Scaling Index Method (SIM), which reveals local topology of the structure, and the Minkowski Functionals (MF), which provide four global topological characteristics, to assess strength of the trabecular network of the human bone. We compare capabilities of these methods with the standard analysis, biomechanical Finite Element Method (FEM) and morphological parameters, in prediction of bone strength and fracture risk. Our study is based on a sample of 151 specimens taken from the trabecular part of human thoracic and lumbar vertebrae in vitro, visualised using CT imaging (isotropic resolution 26 m) and tested by uniaxial compression. The sample of donors is heterogeneous, consisting of 58 male and 54 female cadavers with a mean age of 80 ± 10 years. To estimate the predictive power of the methods, we correlate texture measures derived from CT images with the maximum compressive strength (MCS) as obtained in biomechanical tests. A linear regression analysis reveals that the failure load estimated by FEM shows the highest correlation with MCS (Pearson's correlation coefficient r=0.76). None of the methods in current study is superior to the FEM: morphometric parameters give r<0.5, global topological characteristics show r=0.73 for the first Minkowski Functional MF1, which coincides with bone volume fraction BV/TV and r=0.61 for the second Minkowski functional MF2, which coincides with bone surface BS. Although scaling indices provided by SIM correlate only moderately with MCS (r=0.55), texture measures based on the nonlinear combination of local (SIM) and global (MF) topological characteristics demonstrate high correlation with experimental MCS (r=0.74) and with failure load estimated by FEM (r=0.95). Additional advantage of the proposed texture measures is possibility to reveal the role of the topologically different trabecular structure elements for the bone strength.
Lecture Notes in Computer Science, 2012
Osteoporosis, characterized by low bone mineral density (BMD) and micro-architectural deterioration of trabecular bone (TB), increases risk of fractures associated with substantial morbidity, mortality, and financial costs. A quantitative measure of TB micro-architecture with high reproducibility, large between-subjects variability and strong association with bone strength that may be computed via in vivo imaging would be an important indicator of bone quality for clinical trials evaluating fracture risks under different clinical conditions. Previously, the notion of tensor scale (t-scale) was introduced using an ellipsoidal model that yields a unified representation of structure size, orientation and anisotropy. Here, we develop a new 3-D t-scale algorithm for fuzzy objects and investigate its application to compute quantitative measures characterizing TB micro-architecture acquired by in vivo multi-row detector CT (MD-CT) imaging. Specifically, new measures characterizing individual trabeculae on the continuum of a perfect plate and a perfect rod and their orientation are directly computed in a volumetric BMD representation of a TB network. Reproducibility of these measures is evaluated using repeat MD-CT scans and also by comparing their correlation between MD-CT and µ-CT imaging. Experimental results have demonstrated that the t-scale-based TB micro-architectural measures are highly reproducible with strong association of their values at MD-CT and µ-CT resolutions. Results of an experimental mechanical study have proved these measures' ability to predict TB's bone strength.
A CT-image-based framework for the holistic analysis of cortical and trabecular bone morphology
This study introduces a standardized framework for the holistic analysis of cortical and trabecular bone structure. This method, although applicable to all bones of the skeleton, is particularly useful for irregular-shaped or small bones for which the application of traditional methods has been especially challenging. Traditional analyses have quantified cortical or trabecular structure in only selected regions of a bone, such as single cross-sections of cortical bone or volumes of interest of trabecular structure in epiphyses. The proposed method improves on these traditional methods by visualizing and quantifying the internal bony structure throughout the entire bone and in userdefined anatomical subregions. Here, we describe and demonstrate the method using high-resolution microtomographic scans of a first metacarpal of an orangutan, gorilla, chimpanzee and human. Using automated morphological filters, the cortical bone is defined and extracted from the underlying trabecular structure to create two 3D models, one of the cortex and one of the trabecular bone that can be analysed separately. We test the sensitivity of the morphological parameters used to create these 3D models, demonstrating that the parameters defined here are robust and can provide accurate measures of cortical thickness, relative bone density, trabecular orientation, trabecular thickness and degree of anisotropy. This new, holistic method is able to reveal morphological and functional information about bone loading that is obscured or ignored using traditional methods, thus providing more informed interpretations of behaviour in extant and fossil taxa.
Imaging of trabecular bone structure in osteoporosis
European Radiology, 1999
Osteoporosis is a metabolic bone disorder that is characterized by reduced bone mass and a deterioration of bone structure which results in an increased fracture risk. Since the disease is preventable, diagnostic techniques are of major importance. Standard techniques determine bone mineral density, whereas some of the newer techniques focus on trabecular structure. This article reviews structure analysis techniques in the diagnosis of osteoporosis. Imaging techniques applied to the assessment of trabecular bone structure include conventional radiography, magnification radiography, high-resolution CT (HRCT) and high-resolution MR imaging (HRMRI). The best results were obtained using high-resolution tomographic techniques. The highest spatial resolutions in vivo were achieved using HRMRI. The most common texture analysis techniques that have been used are morphological parameters (analogous to bone histomorphometry). Fractal dimension, co-occurrence matrices, mathematical filter techniques and autocorrelation functions are more complex techniques. Most of the studies evaluating structure analysis show that texture parameters and bone mineral density both predict bone strength and osteoporotic fractures, and that combining both techniques yields the best results in the diagnosis of osteoporosis.
Medical Physics, 1998
The measurement of bone microstructure as well as bone mineral density may improve the estimation of bone strength. Cubic specimens ͑Nϭ26, 12 mmϫ12 mmϫ12 mm͒ of human cadaver vertebrae were cut along three orthogonal anatomic orientations, i.e., superior-inferior ͑SI͒, mediallateral ͑ML͒, and anterior-posterior ͑AP͒. Contact radiographs of the bone cubes along all three orientations were obtained and then digitized by a laser scanner with pixel size of 50 mϫ50 m. The specimens were tested in compression along the 3 orthogonal orientations and the Young's modulus ͑YM͒ was calculated for each direction. Quantitative computed tomography ͑QCT͒ was used to obtain a measure of trabecular bone mineral density ͑BMD͒. Global gray level thresholding and local thresholding algorithms were used to extract the trabecular bone network. Apparent trabecular bone fraction ͑ABV/TV͒, mean intercept length ͑I.TH͒, mean intercept separation ͑I.SP͒, and number of nodes ͑N.ND͒ were measured from the extracted trabecular network. Fractal dimension ͑Fr.D͒ of the trabecular bone texture was also measured. Paired t-tests showed that the mean values of each texture parameter ͑except ABV/TV͒ and of YM along the SI direction were significantly different (pϽ0.05) from those along the ML and AP direction. However, the mean values along the ML and AP directions were not significantly different. Multivariate regression of YM as a function of the texture parameters and BMD showed that without adjusting for the effect of BMD, YM was significantly explained by all the texture parameters (R 2 ϭ0.2-0.6). When BMD was included in the regression, although the variations in YM of ML, AP, and SI orientations could be explained by BMD alone, some of the texture parameters did improve the overall prediction of the biomechanical properties, while, some parameters such as ABV/TV and Fr.D in the ML orientation showed a more significant overall effect in explaining mechanical strength than did BMD. In conclusion, trabecular texture parameters correlated significantly with BMD and YM. Trabecular texture parameters from projectional radiographs reflect the anisotropy of trabecular structure. Quantitative radiographic assessment of trabecular structure using fine-detail radiography can potentially improve the estimation of bone strength. © 1998 American Association of Physicists in Medicine. ͓S0094-2405͑98͒02410-9͔
Topological analysis of trabecular bone MR images
IEEE Transactions on Medical Imaging, 2000
Recently, imaging techniques have become available which permit non-destructive analysis of the three-dimensional (3D) architecture of trabecular bone (TB), which forms a network of interconnected plates and rods. Most osteoporotic fractures occur at locations rich in TB, which has spurred the search for architectural parameters as determinants of bone strength. In this paper, we present a new approach to quantitative characterization of the 3D micro-architecture of TB, based on digital topology. The method classifies each voxel of the 3D structure based on the connectivity information of neighboring voxels. Following conversion of the 3D digital image to a skeletonized surface representation containing only one-and two-dimensional structures, each voxel is classified as a curve, surface, or junction. The method has been validated by means of synthesized images and has subsequently been applied to TB images from the human wrist. The topological parameters were found to predict Young's modulus for uniaxial loading; specifically, the surface-to-curve ratio was found to be the single strongest predictor of Young's modulus (r 2 = 0.69). Finally, the method has been applied to TB images from a group of patients showing very large variations in topological parameters that parallel much smaller changes in bone volume fraction.
Medical Physics, 2010
Hip fracture is a serious health problem and textural methods are being developed to assess bone quality. The authors aimed to perform textural analysis at femur on high-resolution digital radiographs compared to three-dimensional ͑3D͒ microarchitecture comparatively to bone mineral density. Methods: Sixteen cadaveric femurs were imaged with an x-ray device using a C-MOS sensor. One 17 mm square region of interest ͑ROI͒ was selected in the femoral head ͑FH͒ and one in the great trochanter ͑GT͒. Two-dimensional ͑2D͒ textural features from the co-occurrence matrices were extracted. Site-matched measurements of bone mineral density were performed. Inside each ROI, a 16 mm diameter core was extracted. Apparent density ͑D app ͒ and bone volume proportion ͑BV/ TV Arch ͒ were measured from a defatted bone core using Archimedes' principle. Microcomputed tomography images of the entire length of the core were obtained ͑Skyscan 1072 ® ͒ at 19.8 m of resolution and usual 3D morphometric parameters were computed on the binary volume after calibration from BV/ TV Arch. Then, bone surface/bone volume, trabecular thickness, trabecular separation, and trabecular number were obtained by direct methods without model assumption and the structure model index was calculated. Results: In univariate analysis, the correlation coefficients between 2D textural features and 3D morphological parameters reached 0.83 at the FH and 0.79 at the GT. In multivariate canonical correlation analysis, coefficients of the first component reached 0.95 at the FH and 0.88 at the GT. Conclusions: Digital radiographs, widely available and economically viable, are an alternative method for evaluating bone microarchitectural structure.