Figure - available from: Physics in Medicine & Biology
This content is subject to copyright. Terms and conditions apply.
Reproducibility of VTA-based characterization of TB plate/rod micro-architecture for in vivo repeat MR scans of the distal radius on a 1.5 T whole-body MR scanner: (a) axial image and ROI (red). (b) Bone volume fraction (BVF). (c) VTA-based color-coded plate/rod classification of individual trabeculae. (d)–(i) Same as (a)–(c) over the matching image slice from the post-registered repeat scan data.
Source publication
Osteoporosis is associated with increased risk of fractures, which is clinically defined by low bone mineral density. Increasing evidence suggests that trabecular bone (TB) micro-architecture is an important determinant of bone strength and fracture risk. We present an improved volumetric topological analysis algorithm based on fuzzy skeletonizatio...
Citations
... DTA can also be expanded to volumetric topological analysis (VTA) by applying a fuzzy distance transform [55] . With VTA, thickness-based metrics such as trabecular thickness (Tb.Th), trabecular separation, also known as trabecular spacing (Tb.Sp), the assignment of thickness to plate and rod structures detected through DTA, and measurements of plate-width (PW) and plate-to-rod ratio (PRR) can be derived [56][57][58] . This suite of measurements was shown to be translatable to multidetector row CT and cone beam microCT in a validation study by Chen et al. [59] . ...
Objective: To highlight published quantitative morphometric analysis (QMA) methods for assessing tibiofemoral joint osteoarthritis in magnetic resonance imaging and computed tomography and underline the need for open and interoperable protocols for quantitative image analysis.
Design: A literature search on PubMed/MEDLINE and Web of Science of keywords relating to QMA in magnetic resonance imaging and computed tomography in the context of tibiofemoral osteoarthritis in the past 23 years (2000-2022). The search was based on, but not limited to: “quantitative morphometric analysis” or “quantitative image analysis” in combination with “osteoarthritis”, “articular cartilage”, “subchondral bone”, “tibiofemoral joint”, “joint”, “CT”, and “MRI”. The search provided 73 relevant publications that were manually screened and sorted for QMA methods. Further search to extract key functions of the underlying algorithms was performed.
Result: MRI is generally used for QMA of articular cartilage and joint contact area, while CT is generally used for QMA of subchondral bone and joint space width. Studies have shown that QMA algorithms can be adapted to new tissues and modalities. However, many methods are not easily accessible, and there exists a fragmentation of computational tools and platforms in the research field.
Conclusion: QMA is an active research area, and many techniques from one modality can be readily extended to another. Adoption of open-source practices can allow algorithms developed for other imaging modalities to be shared, making it possible to bridge the knowledge gap for structures and pathological features for which QMA has not yet been investigated and increase research output overall.
... The ROIs were binarized using local adaptive thresholding to segment the image into trabeculae and marrow following the previous study [29]. The local thickness was calculated using distance transformation [30], which was assigned to each pixel in the trabeculae as the Euclidean distance from the pixel to the nearest pixel of the marrow. Redundant pixels were then removed by skeletonizing the trabeculae to produce morphological skeletons. ...
Background
To develop a magnetic resonance imaging (MRI)-based radiomics predictive model for the identification of knee osteoarthritis (OA), based on the tibial and femoral subchondral bone, and compare with the trabecular structural parameter-based model.
Methods
Eighty-eight consecutive knees were scanned with 3T MRI and scored using MRI osteoarthritis Knee Scores (MOAKS), in which 56 knees were diagnosed to have OA. The modality of sagittal three-dimensional balanced fast-field echo sequence (3D BFFE) was used to image the subchondral bone. Four trabecular structural parameters (bone volume fraction [BV/TV], trabecular thickness [Tb.Th], trabecular separation [Tb.Sp], and trabecular number) and 93 radiomics features were extracted from four regions of the lateral and medial aspects of the femur condyle and tibial plateau. Least absolute shrinkage and selection operator (LASSO) was used for feature selection. Machine learning-based support vector machine models were constructed to identify knee OA. The performance of the models was assessed by area under the curve (AUC) of the receiver operator characteristic (ROC). The correlation between radiomics features and trabecular structural parameters was analyzed using Pearson’s correlation coefficient.
Results
Our radiomics-based classification model achieved the AUC score of 0.961 (95% confidence interval [CI], 0.912–1.000) when distinguishing between normal and knee OA, which was higher than that of the trabecular parameter-based model (AUC, 0.873; 95% CI, 0.788–0.957). The first-order, texture, and Laplacian of Gaussian-based radiomics features correlated positively with Tb.Th and BV/TV, but negatively with Tb.Sp ( P < 0.05).
Conclusions
Our results suggested that our MRI-based radiomics models can be used as biomarkers for the classification of OA and are superior to the conventional structural parameter-based model.
... 54 However, several other methods exist, including digital topological analysis, geodesic topological analysis, local inertial anisotropy, volumetric topological analysis, and tensor scale analysis. [58][59][60][61][62][63][64] Finite element analysis (FEA) has also been previously used to compute the elastic modulus and to measure bone strength. [65][66][67] In this regard, FEA applied to MRI data has shown to be a promising approach that can reliably provide fracture risk information and evaluation of bone strength with good reproducibility of FEA measurements, furthermore pointing at good agreement of the method against the gold standard of mechanical testing at the femur. ...
Osteoporosis is a systemic skeletal disease with a high prevalence worldwide, characterized by low bone mass and microarchitectural deterioration, predisposing an individual to fragility fractures. Dual‐energy X‐ray absorptiometry (DXA) has been the clinical reference standard for diagnosing osteoporosis and for assessing fracture risk for decades. However, other imaging modalities are of increasing importance to investigate the etiology, treatment, and fracture risk. The purpose of this work is to review the available literature on quantitative magnetic resonance imaging (MRI) methods and related findings in osteoporosis at the spine and proximal femur as the clinically most important fracture sites. Trabecular bone microstructure analysis at the proximal femur based on high‐resolution MRI allows for a better prediction of osteoporotic fracture risk than DXA‐based bone mineral density (BMD) alone. In the 1990s, T2* mapping was shown to correlate with the density and orientation of the trabecular bone. Recently, quantitative susceptibility mapping (QSM), which overcomes some of the limitations of T2* mapping, has been applied for trabecular bone quantifications at the spine, whereas ultrashort echo time (UTE) imaging provides valuable surrogate markers of cortical bone quantity and quality. Magnetic resonance spectroscopy (MRS) and chemical shift encoding‐based water–fat MRI (CSE‐MRI) enable the quantitative assessment of the nonmineralized bone compartment through extraction of the bone marrow fat fraction (BMFF). Furthermore, CSE‐MRI allows for the differentiation of osteoporotic vs. pathologic fractures, which is of high clinical relevance. Lastly, advanced postprocessing and image analysis tools, particularly considering statistical parametric mapping and region‐specific BMFF distributions, have high potential to further improve MRI‐based fracture risk assessments at the spine and hip.
Level of Evidence
5
Technical Efficacy Stage
2
... High resolution imaging techniques has been successfully applied in the field of TB microstructural analysis, including MRI [33] and CT [9]. In comparison to MRI, intensity values of CT images has corresponding physical significance and helps researcher to interpret meanings of each pixel. ...
Skeletonization provides a compact yet effective representation of an object using its medial loci defined by Blum’s grassfire transform process. It has been popularly used in many low- as well as high-level imaging applications. Quantitative characterization of object structures is a popular application of skeletonization, where a skeleton serves two purposes—generations of a compact representation of an object and location of representative points for defining local structure morphology. This paper reviews the roles of skeletonization and digital topological analysis in characterizing individual trabecular bone plate-rod microstructure assessing overall bone quality and fracture risk at in vivo imaging.
The study of bone morphology is of great importance as bone morphology is influenced by factors such as age and underlying comorbidities and is associated with bone mechanical properties and fracture risk. Standard diagnostic techniques used in bone disease, such as Dual-Energy X-ray absorptiometry and ultrasonography do not provide qualitative and quantitative morphological information. In recent years, techniques such as High Resolution Computed Tomography (HR-CT), micro- CT, Magnetic Resonance Imaging (MRI), and Low Field Nuclear Magnetic Resonance (LF-NMR) have been developed for the study of bone structure and porosity. Data obtained from these techniques have been used to construct models to predict bone mechanical properties thanks to finite element analysis. Cortical porosity has been extensively studied and successfully correlated with disease progression and mechanical properties. Trabecular porosity and pore size distribution, however, have increasingly been taken into consideration to obtain a comprehensive analysis of bone pathology and mechanic. Therefore, we have decided to evaluate the ability of micro- CT (chosen for its high spatial resolving power) and LF-NMR (chosen to analyze the behavior of water molecules within trabecular bone pores) to characterize the morphology of trabecular bone in osteoporosis. Trabecular bone samples from human femoral heads collected during hip replacement surgery were from osteoporosis (test group) and osteoarthritis (control group) patients. Our data show that both micro- CT and LF-NMR can detect qualitative changes in trabecular bone (i.e., transition from plate-like to rod-like morphology). Micro- CT failed to detect significant differences in trabecular bone morphology parameters between osteoporotic and osteoarthritic specimens, with the exception of Trabecular Number and Connectivity Density, which are markers of osteoporosis progression. In contrast, LF-NMR was able to detect significant differences in porosity and pore size of trabecular bone from osteoporotic versus osteoarthritic (control) samples. However, only the combination of these two techniques allowed the detection of structural morphometric changes (increase in the larger pore fraction and enlargement of the larger pores) in the trabecular bone of osteoporotic specimens compared to osteoarthritic ones. In conclusion, the combined use of LF-NMR and micro- CT provides a valuable tool for characterizing the morphology of trabecular bone and may offer the possibility for a new approach to the study and modeling of bone mechanics in the context of aging and disease.
Twenty men with spinal cord injury (SCI) were randomized into two 16-week intervention groups receiving testosterone treatment (TT) or TT combined with resistance training (TT + RT). TT + RT appears to hold the potential to reverse or slow down bone loss following SCI if provided over a longer period.IntroductionPersons with SCI experience bone loss below the level of injury. The combined effects of resistance training and TT on bone quality following SCI remain unknown.Methods
Men with SCI were randomized into 16-week treatments receiving TT or TT + RT. Magnetic resonance imaging (MRI) of the right lower extremity before participation and post-intervention was used to visualize the proximal, middle, and distal femoral shaft, the quadriceps tendon, and the intermuscular fascia of the quadriceps. For the TT + RT group, MRI microarchitecture techniques were utilized to elucidate trabecular changes around the knee. Individual mixed models were used to estimate effect sizes.ResultsTwenty participants completed the pilot trial. A small effect for yellow marrow in the distal femur was indicated as increases following TT and decreases following TT + RT were observed. Another small effect was observed as the TT + RT group displayed greater increases in intermuscular fascia length than the TT arm. Distal femur trabecular changes for the TT + RT group were generally small in effect (decreased trabecular thickness variability, spacing, and spacing variability; increased network area). Medium effects were generally observed in the proximal tibia (increased plate width, trabecular thickness, and network area; decreased trabecular spacing and spacing variability).Conclusions
This pilot suggests longer TT + RT interventions may be a viable rehabilitation technique to combat bone loss following SCI.Clinical trial registrationRegistered with clinicaltrials.gov: NCT01652040 (07/27/2012).
The objective of this thesis was the development of a biohybrid substitute for the reconstruction of the bone-tendon continuum based on tissue engineering strategies. After an exhaustive bibliographic analysis of the native structures and their environment, we first proposed the realization of each system separately using electrospun polycaprolactone scaffolds. At first, we combined electrospinning with electrospraying techniques to produce a PCL-hydroapatite scaffold with honeycomb cavities. Our hypothesis was to provide the substitute with a biomimetic structure favoring cell adhesion, spreading and differentiation. The in vitro mechanical and biological analysis performed with a progenitor cell line and withorganotypic assays confirmed our original approach. Then, the material seeded with bone marrow stem cells was successfully implanted by our collaborators in Amiens with the objective of treating a maxillofacial defect in a rodent model. In parallel, for the tendon reconstruction, we investigated several electrospinning processes, varying fibers’ size and organization (random/aligned). In a bioinspired perspective, we combined the choice of the scaffold with dynamic stretching to reproduce physical training. Under those mechanical stimulations, established first with the same progenitor cell line, we demonstrated in a second study that MSCs aligned with the stretching axis and produced extracellular matrix, which in turn allowed to keep the mechanical properties of the biohybrid scaffold all over the 2 weeks of culture. We demonstrated that cell differentiation towards tendon and bone lineage was successfully achieved in the absence of any differentiation factor, being specifically related to materials properties and mechanotransduction. Therefore, the next step consisting in the assembly of both scaffolds with a transition area should lead to this bone-tendon continuum’s reconstruction.
Introdução: Diabetes mellitus é uma doença metabólica que afeta vários órgãos-alvo, incluindo os ossos. OBJETIVO: Avaliar pelo método de esqueletonização o efeito do Diabetes mellitus tipo I (DM1) na microarquitetura de osso esponjoso. Material e Métodos: Quatorze ratos Wistar foram divididos em: Saudável (S, n=7) e Diabético (D, n=7). O DM1 foi induzido por meio de injeção endovenosa de estreptozotocina no grupo D, sendo a confirmação da condição realizada por checagem do nível glicêmico. Os animais foram sacrificados após 35 dias da indução no grupo D, juntamente com os do grupo S. As epífises femorais foram seccionadas, removidas, desmineralizadas e incluídas em parafina. Dois cortes (5 µm) foram obtidos, corados em Hematoxilina e Eosina, e analisados ao Microscópio de Luz. Foi realizada a delimitação interativa das trabéculas ósseas, seguido pelo processo de binarização utilizando threshold global, feita por dois operadores distintos. Depois, foi realizado o processo de esqueletonização para acesso às características das trabéculas e da rede de interconexão entre elas. Os parâmetros avaliados foram: Área óssea em micrômetros quadrados (B.Ar), Índice de Modelo estrutural (SMI), Dimensão Fractal (FD), Número de trabéculas (Tb.N), Número de ramos (B.N), Número total de junções (Junc.N), Média de pontos terminais (End.p), Média de extensão de cada ramo (R.Le) e Número de junções triplas (Triple.points.N). Resultados: Houve diferença significante apenas no parâmetro SMI para os diferentes operadores (p
Purpose To determine if 3-T magnetic resonance (MR) imaging of proximal femur microarchitecture can allow discrimination of subjects with and without fragility fracture who do not have osteoporotic proximal femur bone mineral density (BMD). Materials and Methods Sixty postmenopausal women (30 with and 30 without fragility fracture) who had BMD T scores of greater than -2.5 in the hip were recruited. All subjects underwent dual-energy x-ray absorptiometry to assess BMD and 3-T MR imaging of the same hip to assess bone microarchitecture. World Health Organization Fracture Risk Assessment Tool (FRAX) scores were also computed. We used the Mann-Whitney test, receiver operating characteristics analyses, and Spearman correlation estimates to assess differences between groups, discriminatory ability with parameters, and correlations among BMD, microarchitecture, and FRAX scores. Results Patients with versus without fracture showed a lower trabecular plate-to-rod ratio (median, 2.41 vs 4.53, respectively), lower trabecular plate width (0.556 mm vs 0.630 mm, respectively), and lower trabecular thickness (0.114 mm vs 0.126 mm) within the femoral neck, and higher trabecular rod disruption (43.5 vs 19.0, respectively), higher trabecular separation (0.378 mm vs 0.323 mm, respectively), and lower trabecular number (0.158 vs 0.192, respectively), lower trabecular connectivity (0.015 vs 0.027, respectively) and lower trabecular plate-to-rod ratio (6.38 vs 8.09, respectively) in the greater trochanter (P < .05 for all). Trabecular plate-to-rod ratio, plate width, and thickness within the femoral neck (areas under the curve [AUCs], 0.654-0.683) and trabecular rod disruption, number, connectivity, plate-to-rod ratio, and separation within the greater trochanter (AUCs, 0.662-0.694) allowed discrimination of patients with fracture from control subjects. Femoral neck, total hip, and spine BMD did not differ between and did not allow discrimination between groups. FRAX scores including and not including BMD allowed discrimination between groups (AUCs, 0.681-0.773). Two-factor models (one MR imaging microarchitectural parameter plus a FRAX score without BMD) allowed discrimination between groups (AUCs, 0.702-0.806). There were no linear correlations between BMD and microarchitectural parameters (Spearman ρ, -0.198 to 0.196). Conclusion 3-T MR imaging of proximal femur microarchitecture allows discrimination between subjects with and without fragility fracture who have BMD T scores of greater than -2.5 and may provide different information about bone quality than that provided by dual-energy x-ray absorptiometry.©RSNA, 2018.
