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Introduction
Measuring the health of bone is important for understanding the pathogenesis, progression, diagnosis and treatment outcomes for fragility. At present the most common method for measuring bone health in a clinical setting is to assess skeletal mass. The current gold standard is dual-energy X-ray absorptiometry (DXA) which models bones a...
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Context 1
... by also including measures of bone mineral content collected using DXA scans (e.g. Figure 6) the authors were able to improve r 2 =0.760 for CT and r 2 =0.7744 for MRI. Hence apparent trabecular morphology alone was only able to explain 50-55% of the variation in bone strength, but the inclusion of areal bone mineral density increased this to as much as 77%. ...
Context 2
... computer driven system uses algorithms to process patient sseciiic data and calculate the 10-year probability of an osteoporotic frac- ture. Patients ill a uestionnaire on family history and lifestyle as well as bone uality uantiiied as BBD using a DXA scan ( Figure 6). Recent studies have shown that although the system is reasonably accurate the algorithms tend to underestimate the risk of fracture in women, particularly those in the most at risk group over 65 years [44][45] . ...
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Citations
... BMD describes bone quality as the mineral content in the certain volume of bone tissue with all its structures [4]. On the other hand TMD describes mineral contents in the bone matrix only and with three dimensional morphological parameters of trabecular and cortical bone reflects bone mechanical properties [5]. Some studies indicate that TMD can reveal elastic, plastic, and viscoelastic mechanical properties of bone tissue [6,7,8]. ...
... Conventional computed tomography (CT) scans (normally known as volumetric CT) [12,13] have been used alongside mechanical testing to map the geometry and density distribution of bone (as measured by X-ray absorption). Although the resolution is low, the smallest voxel size that can be obtained is approximately 300 9 300 9 1000 lm (pixel length 9 width 9 slice thickness) [14]. Higher-resolution benchtop micro-CT systems have been used to image bone at the microscale with voxels in the order of 5-100 lm [15,16]. ...
... The third order is the best integral peak because the first-order peak has a much higher diffuse noise from mineral platelets mineral density (BMD) and predict fracture risk of patients. Yet, the technique does not fully explain the increase in fracture risk with age because the images are 2D and do not capture the complex hierarchical structure of bone and the variation in tissue-level mechanical properties of bone [14,96]. Synchrotron micro-CT is occasionally used for accurately measuring tissue mineral density [97] and also can be used to analyze the porosity and other structural features of bone, such as microcracks, [71]. ...
Bone is a complex hierarchical structure, and its principal function is to resist mechanical forces and fracture. Bone strength depends not only on the quantity of bone tissue but also on the shape and hierarchical structure. The hierarchical levels are interrelated, especially the micro-architecture, collagen and mineral components; hence, analysis of their specific roles in bone strength and stiffness is difficult. Synchrotron imaging technologies including micro-CT and small/wide angle X-ray scattering/diffraction are becoming increasingly popular for studying bone because the images can resolve deformations in the micro-architecture and collagen–mineral matrix under in situ mechanical loading. Synchrotron cannot be directly applied in vivo due to the high radiation dose but will allow researchers to carry out systematic multifaceted studies of bone ex vivo. Identifying characteristics of aging and disease will underpin future efforts to generate novel devices and interventional therapies for assessing and promoting healthy aging. With our own research work as examples, this paper introduces how synchrotron imaging technology can be used with in situ testing in bone research.
... BMD testing only measures the areal bone mass and does not capture any structural information because images are 2D. Thus BMD is not an adequate surrogate marker of bone strength; it only explains about 50 % of ex vivo strength (7). ...
Osteoporosis with resultant fractures is a major global health problem with huge socio-economic implications for patients, families and healthcare services. Areal (2D bone mineral density (BMD) assessment is commonly used for predicting such fracture risk, but is unreliable, estimating only about 50% of bone strength. By contrast, computed tomography (CT) based techniques could provide improved metrics for estimating bone strength such as bone volume fraction (BVF; a 3D volumetric measure of mineralised bone), enabling cheap, safe and reliable strategies for clinical application, and to help divert resources to patients identified as most likely to benefit, meeting an unmet need. Here we describe a novel method for measuring BVF at clinical-CT like low-resolution (550µm voxel size). Femoral heads (n=8) were micro-CT scanned ex-vivo. Micro-CT data were downgraded in resolution from 30µm to 550µm voxel size and BVF calculated at high and low resolution. Experimental mechanical testing was applied to measure ex vivo bone strength of samples. BVF measures collected at high-resolution showed high correlation (correlation coefficient r2=0.95) with low-resolution data. Low-resolution BVF metrics showed high correlation (r2=0.96) with calculated sample strength. These results demonstrate that measuring BVF at low resolution is feasible, which also predicts bone strength. Measures of BVF should be useful for clinically estimating bone strength and fracture risk. The method needs to be validated using clinical CT scans.
... In fact, BMD only accounts for about 40-50% of the in vitro compressive strength of bone, whilst structure contributes as much as 30-40% of the remainder [23]. Following these discoveries, a new understanding of bone strength-termed bone quality, operationally defined as the structural and mechanical basis of bone strength, was developed [24]. Bone quality is an amalgamation of all the factors that determine how well a skeleton can resist fracturing, including the micro-architecture, accumulated microscopic damage, quality of collagen, size of mineral crystals and the rate of bone turnover [19]. ...
Prostate cancer is a large clinical burden across Europe. It is, in fact, the most common cancer in males, accounting for more than 92,300 deaths annually throughout the continent. Prostate cancer is androgen-sensitive; thus an androgen deprivation therapy (ADT) is often used for treatment by reducing androgen to castrate levels. Several ADT agents have achieved benefits with effective palliation, but, unfortunately, severe adverse events are frequent. Contemporary ADT (Luteinising Hormone Releasing Hormone agonist - LHRHa injections) can result in side effects that include osteoporosis and fractures, compromising quality of life and survival.
In this review we analysed the associated bone toxicity consequent upon contemporary ADT and based on the literature and our own experience we present future perspectives that seek to mitigate this associated toxicity both by development of novel therapies and by better identification and prediction of fracture risk.
Preliminary results indicate that parenteral oestrogen can mitigate associated osteoporotic risk and that CT scans could provide a more accurate indicator of overall bone quality and hence fracture risk.
As healthcare costs increase globally, cheap and effective alternatives that achieve ADT, but mitigate or avoid such bone toxicities, will be needed. More so, innovative techniques to improve both the measurement and the extent of this toxicity, by assessing bone health and prediction of fracture risk, are also required.
Bioarcheology (the study of archeological human remains together with contextual and documentary evidence) offers a unique vantage point to examine variation in skeletal morphology related to influences such as activity, disease, and nutrition. The human skeleton is composed of a dynamic tissue that is forged by biocultural factors over the entire life course, providing a record of individual, and community history. Various aspects of adult bone health, particularly bone maintenance and loss and the associated skeletal disease osteoporosis, have been examined in numerous past populations. The anthropological study of bone loss has traditionally focused on the signature of postmenopausal aging, costs of reproduction, and fragility in females. The a priori expectation of normative sex‐related bone loss/fragility in bioanthropological studies illustrates the wider gender‐ideological bias that continues in research design and data analysis in the field. Contextualized data on bone maintenance and aging in the archeological record show that patterns of bone loss do not constitute predictable consequences of aging or biological sex. Instead, the critical examination of bioarcheological data highlights the complex and changing processes that craft the human body over the life course, and calls for us to question the ideal or “normal” range of bone quantity and quality in the human skeleton, and to critically reflect on what measures are actually biologically and/or socially meaningful.
Different kinds of bone measurements are commonly derived from computed‐tomography (CT) volumes to answer a multitude of questions in biology and related fields. The underlying steps of bone segmentation and, optionally, polygon surface generation are crucial to keep the measurement error small. In this study, the performance of different, easily accessible segmentation techniques (global thresholding, automatic local thresholding, weighted random walk, neural network, and watershed) and surface generation approaches (different algorithms combined with varying degrees of simplification) was analyzed and recommendations for minimizing inaccuracies were derived. The different approaches were applied to synthetic CT volumes for which the correct segmentation and surface geometry were known. The most accurate segmentations of the synthetic volumes were achieved by setting a case‐specific window to the gray value histogram and subsequently applying automatic local thresholding with appropriately chosen thresholding method and radius. Surfaces generated by the Amira® module Generate Lego Surface in combination with careful surface simplification were the most accurate. Surfaces with sub‐voxel accuracy were obtained even for synthetic CT volumes with low contrast‐to‐noise ratios. Segmentation trials with real CT volumes supported the findings. Very accurate segmentations and surfaces can be derived from CT volumes by using readily accessible software packages. The presented results and derived recommendations will help to reduce the measurement error in future studies. Furthermore, the demonstrated strategies for assessing segmentation and surface qualities can be adopted to quantify the performance of new segmentation approaches in future studies.
