Analysis Of Trabecular Bone Structure Research Articles

An Analysis of Trabecular Bone Structure Based on Principal Stress Trajectory.

To understand the mechanism of Wolff's law, a finite element analysis was performed for a human proximal femur, and the principal stress trajectories of the femur were extracted using the principal stress visualization method. The mechanism of Wolff's law was evaluated theoretically based on the distribution of the principal stress trajectories. Due to the dynamics of the loads, there was no one-to-one correspondence between the stress trajectories of the fixed load and the trabeculae in the cancellous architecture of the real bone. The trabeculae in the cancellous bone were influenced by the magnitude of the principal stress trajectory. Equivalent principal stress trajectories suitable for different load changes were proposed through the change in load cycle and compared with the anatomical structure of the femur. In addition, the three-dimensional distribution of the femoral principal stress trajectory was established, and the adaptability potential of each load was discussed. The principal stress visualization method could also be applied to bionic structure design.

The influence of body size and phylogeny on trabecular microstructure in the proximal femur and humerus of rodents and primates

Life history theory states that organisms maximize their fitness via energetic trade‐offs between various biological functions. It has been well‐established that life history strategy is related to intraspecific variation in body size and that body size predicts some bone microstructural properties, but the relationship between life history strategy and skeletal variation has not been sufficiently examined across multiple mammalian clades. Generally, small‐bodied mammals have “fast” life histories and faster growth rates than large‐bodied mammals, meaning small mammals deposit bone tissue at a faster rate, which may affect skeletal morphology. Therefore, the goal of this study was to conduct a preliminary analysis of trabecular bone structure in the rodent and primate humerus and femur to evaluate the influence of life history traits, particularly body size, on bone properties in a phylogenetically diverse sample. Using a sample of 67 size‐matched adult rodent and primate individuals from 8 extant rodent genera (N=26) and 10 extant primate genera (N=41) ranging in body size from 0.04kg to 70kg, we analyzed trabecular bone structure in the proximal femoral and humeral head. Regression analyses were used to assess associations between trabecular bone properties and body size and one‐way ANOVAs were used to compare bone properties between rodents and primates across three size‐matched classes.Regression results are consistent with previous primate and mammal studies. Bone volume fraction (BV/TV) scales with weak positive allometry in both groups and both elements except for the rodent humerus, which scales isometrically. Degree of anisotropy (DA) varies across all groups and shows no consistent relationship with body size. Trabecular thickness (Tb.Th) and trabecular separation (Tb.Sp) increase with body size, while connectivity density (Conn.D) and bone surface density (BS/BV) decrease with body size across both clades and elements. In both groups and both bones, Tb.Th, Tb.Sp, and Conn.D scale with strong negative allometry while BS/BV scales with strong positive allometry. ANOVAs reveal that Tb.Th and Tb.Sp are higher in the primate femur than in the rodent femur for medium and large size classes, while Conn. D is higher in the rodent femur for medium and large size classes. Other bone properties do not show consistent patterns of differences between primates and rodents. Overall, while overlapping confidence intervals for all slopes suggest body size scales similarly with these bone properties across clades, ANOVA results suggest that medium and large bodied rodents have thinner, more numerous trabeculae in the femur compared to similarly‐sized primates. Further investigation is necessary to elucidate the biological significance of this result and the underlying mechanisms driving the observed phenomenon.

Microstructural and mechanical recovery of bone in ovariectomized rats: The effects of menaquinone-7

The loss of bone quantity and quality in postmenopausal female patients can be a problem for dental treatment. A sufficient intake of nutrients such as calcium, magnesium, and vitamins D and K is likely correlated with the mechanical properties of bone. In particular, vitamin K2, also called menaquinone (MK), inhibits bone loss in postmenopausal women. Here we demonstrate the microstructural and mechanical properties of bone recovery in ovariectomized (OVX) rats during MK-7 administration. Bilateral ovariectomy and a sham operation were performed on 14-week-old female SPF Wistar rats. MK-4 and -7 were orally administered at 30 mg/kg daily for 12 weeks. The femur was used for the 3-point bending test and microstructural analysis of the cancellous bone by micro-CT, and the mandibular cortical bone for the evaluation of mechanical properties on a nanoscale. Micro-computed tomography revealed irregular trabecular architecture, hollow marrow cavities, and sparse trabecular bone in the femurs of the OVX group. Trabecular bone structure analysis showed that the MK-7 group had greater bone volume per tissue volume (BV/TV) and a higher trabecular number than the OVX group. The bulk-scale 3-point bending test did not allow the mechanical properties between OVX and OVX/MK7 groups to be discerned, yet at the smallest level, the elastic–plastic transition point of the nanoindentation stress–strain curve of the mandibular cortical bone was higher in the MK-7 group than in the OVX group. These findings suggest that MK-7 enables bone microstructural and mechanical recovery in the OVX model.

OSTEOPOROSIS PRESCREENING USING DENTAL PANORAMIC RADIOGRAPHY WITH DEEP LEARNING

<h3>Background</h3> Known as the most common bone pathosis, osteoporosis affects millions of people every year. Clinical diagnostic methods for osteoporosis are expensive and, therefore, have limited availability in population prescreening. Recently, studies have shown that dental panoramic radiography (DPR) can provide information of bone density changes and have potential to be used in trabecular bone structure analysis. <h3>Objective</h3> The aim of this study was to investigate the potential of using deep neural networks on DPR images for osteoporosis prescreening. <h3>Materials and Methods</h3> We collected 108 DPR images from 108 patients (52 patients with osteoporosis and 56 normal individuals). We designed a deep learning algorithm for osteoporosis prescreening. The algorithm uses a multitask scheme to transfer the network pretrained on ImageNet to our data set and improves accuracy in osteoporosis prescreening. <h3>Results</h3> The leave-one-out cross-validation showed that the highest overall accuracy of osteoporosis prescreening to be 92%, demonstrating its significant advantage over previous methods. <h3>Discussion</h3> The study findings showed that using deep neural networks can significantly improve the accuracy of prescreening for osteoporosis, based on 108 DPR images.

The computed tomography-based fractal analysis of trabecular bone structure may help in detecting decreased quality of bone before urgent spinal procedures

Background ContextTo date, no reliable method is available to determine the parameters of bone density based on the routine spinal computed tomography (CT) in the emergency setup. We propose the use of fractal analysis to detect patients with poor quality of bone before urgent or semi-urgent spinal procedures. PurposeThis study aimed to validate the hypothesis that the CT-based fractal analysis of the trabecular bone structure may help in detecting patients with poor quality of bone before urgent spinal procedures. Study DesignThis is a retrospective analysis of prospectively collected data. MethodsPatients in whom the dual-energy x-ray absorptiometry (DEXA) scan and lumbar spine CT were performed at an interval of no more than 3 months were randomly selected from a prospectively collected database. Diagnostic axial CT scans of L2, L3, and L4 vertebrae were processed to determine the fractal dimension (FD) of the trabecular structure of each spinal level. Box-count method and ImageJ 1.49 software were used. The FD was compared with the results of the DEXA scan: bone mineral density (BMD) and T-score by mean of correlation coefficients. Receiver operating characteristic curve analysis was later performed to determine the cutoff value of FD. ResultsA total of 102 vertebral levels obtained from 35 patients (mean age 60±18 years; 29 female) were analyzed. The FD was significantly higher in the group of patients with decreased bone density (DBD) (T-score<−1.0) (1.67 vs. 1.43; p<.0001) and negatively correlated with BMD (R Spearman, −0.53; p<.0001) and T-score (−0.49; p<.0001). Receiver operating characteristic curve analysis revealed that a cutoff value of FD>1.53 indicates DBD (p<.0001; area under the ROC curve [AUC], 0.84; 95% confidence interval [CI], 0.76–0.91). ConclusionsThis study shows that fractal analysis of the lumbar spine CT images may be used to determine bone density before spinal instrumentation (eg, metastatic or traumatic cord compression). Further prospective studies comparing results of the fractal analysis of CT scans with quantitative CT (qCT) are warranted.

Comparative analysis of trabecular bone structure and orientation in South African hominin tali

Tali of several hominin taxa are preserved in the fossil record and studies of the external morphology of these often show a mosaic of human-like and ape-like features. This has contributed to a growing recognition of variability characterizing locomotor kinematics of Australopithecus. In contrast, locomotor kinematics of another Plio-Pleistocene hominin, Paranthropus, are substantially less well-documented, in part, because of the paucity of postcranial fossils securely attributed to the genus. Since the talus transmits locomotor-based loads through the ankle and its internal structure is hypothesized to reflect accommodation to such loads, it is a cornerstone structure for reconstructing locomotor kinematics. Here we quantify and characterize trabecular bone morphology within tali attributed to Australopithecus africanus (StW 102, StW 363, StW 486) and Paranthropus robustus (TM 1517), making quantitative comparisons to modern humans, extant non-human apes, baboons, and a hominin talus attributed to Paranthropus boisei (KNM-ER 1464). Using high-resolution images of fossil tali (25 μm voxels), nine trabecular bone subregions of interest beneath the articular surface of the talar trochlea were segmented to quantify localized patterns in distribution and primary strut orientation. It was found that trabecular strut orientation and shape, in some cases, can discriminate amongst species characterized by different locomotor foot kinematics. Discriminant function analyses using standard trabecular bone structural properties align TM 1517 with Pan and Gorilla, while other hominin tali structurally most resemble those of baboons. In primary strut orientation, Paranthropus tali (KNM-ER 1464 and TM 1517) resemble the human condition in the anterior-medial subregion, where strut orientation appears positioned to distribute compressive loads medially and distally toward the talar head. In A. africanus tali (particularly StW 486), primary strut orientation in this region resembles that of apes. These results suggest that Paranthropus may have had a human-like medial weight shift during the last half of stance phase but Australopithecus did not.

Microstructural study of the lunate in stage III Kienböck's disease with micro-computed tomography imaging.

Seventeen fresh lunates with stage III Kienböck's disease were scanned with micro-computed tomography. Four regions of interest were selected to measure trabecular parameters, which were compared with those from normal lunates. Within the three regions in the distal surface, there was more compact trabecular bone in the middle region when compared with the palmar and dorsal regions. In the central part, the trabeculae of the Kienböck's lunates were much thicker than those in normal lunates. The diameters of the palmar nutrient foramina of the Kienböck's lunates were significantly smaller than those in normal lunates. In affected lunates, the bony disruptions were mostly located in the palmar or dorsal areas, which were shown from trabecular bone structure analysis to be structurally weaker. This leads to separation of the distal part of the fractured bone, disruption of the blood supply, poor bone remodelling and proneness to secondary fracture and eventual collapse.

Microstructure Study of the Normal Lunates and Kienböck Lunates With MicroCT Imaging

Objective: To compare the microstructure of normal lunates and Kienböck lunates with MicroCT. Materials and Methods: Seventeen fresh lunates from the patients with stage III Kienböck disease and 8 normal lunates were scanned with MicroCT. Four regions of interest were selected to measure the trabecular parameters. The number and diameter of the nutrient foramina were measured. Results: All the Kienböck lunates had bony discontinuity at the distal surface like a greenstick fracture. Within the 3 regions in the distal surface, the bone volume, bone volume density, and the structure model index were significantly larger in the middle region when compared with those of the palm and dorsal regions. Conversely, trabecular separation and bone surface/bone volume were smaller in the middle region. Comparing the central trabecular bones of the Kienböck lunates with those of the normal lunates, we found the bone volume, bone volume density, and bone surface were significantly larger in Kienböck lunates while the trabecular separation and trabecular pattern factor were significantly smaller. There was no significant difference for the number and diameter of the nutrient foramina between 2 sides of Kienböck lunates. The diameters of the nutrient foramina of the Kienböck lunates were significantly larger on the dorsal side and smaller on the palmar side when compared with normal lunates ( P &lt; .05). Conclusion: In Kienböck lunates, the bony disruptions were mostly located in the palmar or dorsal area where it was shown to be structurally weaker from trabecular bone structure analysis, leading to separation of the distal part of the fracture, disruption of blood supply, poor bone remodeling, and proneness to secondary fracture and eventual collapse.

Trabecular bone structure analysis of the spine using clinical MDCT: can it predict vertebral bone strength?

Recent technical improvements have made it possible to determine trabecular bone structure parameters of the spine using clinical multi-detector computed tomography (MDCT). Therefore, the purpose of this study was to analyze trabecular bone structure parameters obtained from clinical MDCT in relation to high resolution peripheral quantitative computed tomography (HR-pQCT) as a standard of reference and to investigate whether clinical MDCT can predict vertebral bone strength. Fourteen functional spinal segment units between T7 and L3 were harvested from 14 formalin-fixed human cadavers (11 women and 3 men; age 84 ± 10 years). All functional spinal segment units were examined using HR-pQCT (isotropic voxel size of 41 μm(3)) and a clinical whole-body MDCT (interpolated voxel size of 146 × 146 × 300 μm(3)). Trabecular bone structure analyses (histomorphometric and texture measures) were performed in the HR-pQCT as well as MDCT images. Vertebral failure load (FL) of the functional spinal segment units was determined in an uniaxial biomechanical test. The HR-pQCT and MDCT derived trabecular bone structure parameters showed correlations ranging from r = 0.60 to r = 0.90 (p < 0.05). Correlations between trabecular bone structure parameters and FL amounted up to r = 0.86 (p < 0.05) using the HR-pQCT images, and up to r = 0.79 (p < 0.05) using the MDCT images. Correlation coefficients of FL versus trabecular bone structure parameters obtained with HR-pQCT and MDCT were not significantly different (p > 0.05). In this cadaver model, the spatial resolution of clinically available whole-body MDCT scanners was suitable for trabecular bone structure analysis of the spine and to predict vertebral bone strength.

Cortical and trabecular bone structure analysis at the distal radius—prediction of biomechanical strength by DXA and MRI

The purpose of this study was to investigate whether the combination of dual-energy X-ray absorptiometry (DXA)-based bone mass and magnetic resonance imaging (MRI)-based cortical and trabecular structural measures improves the prediction of radial bone strength. Thirty-eight left forearms were harvested from formalin-fixed human cadavers. Bone mineral content (BMC) and bone mineral density (BMD) of the distal radius were measured using DXA. Cortical and trabecular structural measures of the distal radius were computed in high-resolution 1.5T MR images. Cortical measures included average cortical thickness and cross-sectional area. Trabecular measures included morphometric and texture parameters. The forearms were biomechanically tested in a fall simulation to measure absolute radial bone strength (failure load). Relative radial bone strength was determined by dividing radial failure loads by age, body mass index, radius length, and average radius cross-sectional area, respectively. DXA derived BMC and BMD showed statistically significant (p<0.05) correlations with absolute and relative radial bone strength (r≤0.78). Correlation coefficients for cortical and trabecular structural measures with absolute and relative radial bone strength amounted up to r=0.59 and r=0.74, respectively, (p<0.05). In combination with DXA-based bone mass, trabecular but not, cortical structural measures, added in multiple regression models significant (p<0.05) information in predicting absolute and relative radial bone strength (up to R adj=0.88). Thus, a combination of DXA-based bone mass and MRI-based trabecular structural measures most accurately predicted absolute and relative radial bone strength, whereas structural measures of the cortex did not provide significant additional information in combination with DXA.

Automated 3D trabecular bone structure analysis of the proximal femur—prediction of biomechanical strength by CT and DXA

SummaryThe standard diagnostic technique for assessing osteoporosis is dual X-ray absorptiometry (DXA) measuring bone mass parameters. In this study, a combination of DXA and trabecular structure parameters (acquired by computed tomography [CT]) most accurately predicted the biomechanical strength of the proximal femur and allowed for a better prediction than DXA alone.IntroductionAn automated 3D segmentation algorithm was applied to determine specific structure parameters of the trabecular bone in CT images of the proximal femur. This was done to evaluate the ability of these parameters for predicting biomechanical femoral bone strength in comparison with bone mineral content (BMC) and bone mineral density (BMD) acquired by DXA as standard diagnostic technique.MethodsOne hundred eighty-seven proximal femur specimens were harvested from formalin-fixed human cadavers. BMC and BMD were determined by DXA. Structure parameters of the trabecular bone (i.e., morphometry, fuzzy logic, Minkowski functionals, and the scaling index method [SIM]) were computed from CT images. Absolute femoral bone strength was assessed with a biomechanical side-impact test measuring failure load (FL). Adjusted FL parameters for appraisal of relative bone strength were calculated by dividing FL by influencing variables such as body height, weight, or femoral head diameter.ResultsThe best single parameter predicting FL and adjusted FL parameters was apparent trabecular separation (morphometry) or DXA-derived BMC or BMD with correlations up to r = 0.802. In combination with DXA, structure parameters (most notably the SIM and morphometry) added in linear regression models significant information in predicting FL and all adjusted FL parameters (up to R adj = 0.872) and allowed for a significant better prediction than DXA alone.ConclusionA combination of bone mass (DXA) and structure parameters of the trabecular bone (linear and nonlinear, global and local) most accurately predicted absolute and relative femoral bone strength.

Trabecular Bone Structure Analysis in the Osteoporotic Spine Using a Clinical In Vivo Setup for 64-Slice MDCT Imaging: Comparison to μCT Imaging and μFE Modeling

Assessment of trabecular microarchitecture may improve estimation of biomechanical strength, but visualization of trabecular bone structure in vivo is challenging. We tested the feasibility of assessing trabecular microarchitecture in the spine using multidetector CT (MDCT) on intact human cadavers in an experimental in vivo-like setup. BMD, bone structure (e.g., bone volume/total volume = BV/TV; trabecular thickness = Tb.Th; structure model index = SMI) and bone texture parameters were evaluated in 45 lumbar vertebral bodies using MDCT (mean in-plane pixel size, 274 microm(2); slice thickness, 500 microm). These measures were correlated with structure measures assessed with microCT at an isotropic spatial resolution of 16 microm and to microfinite element models (microFE) of apparent modulus and stiffness. MDCT-derived BMD and structure measures showed significant correlations to the density and structure obtained by microCT (BMD, R(2) = 0.86, p < 0.0001; BV/TV, R(2) = 0.64, p < 0.0001; Tb.Th, R(2) = 0.36, p < 0.01). When comparing microCT-derived measures with microFE models, the following correlations (p < 0.001) were found for apparent modulus and stiffness, respectively: BMD (R(2) = 0.58 and 0.66), BV/TV (R(2) = 0.44 and 0.58), and SMI (R(2) = 0.44 and 0.49). However, the overall highest correlation (p < 0.001) with microFE app. modulus (R(2) = 0.75) and stiffness (R(2) = 0.76) was achieved by the combination of QCT-derived BMD with the bone texture measure Minkowski Dimension. In summary, although still limited by its spatial resolution, trabecular bone structure assessment using MDCT is overall feasible. However, when comparing with microFE-derived bone properties, BMD is superior compared with single parameters for microarchitecture, and correlations further improve when combining with texture measures.

Assessment of trabecular bone structure using MDCT: comparison of 64- and 320-slice CT using HR-pQCT as the reference standard

ObjectivesThe aim of our study was to perform trabecular bone structure analysis with images from 64- and 320-slice multidetector computed tomography (MDCT) and to compare these with high-resolution peripheral computed tomography (HR-pQCT).Materials and methodsTwenty human cadaver distal forearm specimens were imaged on a 64- and 320-slice MDCT system at 120 kVp, 200 mA and 135 kVp, 400 mA (in-plane pixel size 234 µm; slice thickness 500 µm). HR-pQCT imaging was performed at an isotropic voxel size of 41 µm. Bone volume fraction (BV/TV), trabecular number (Tb.N), thickness (Tb.Th) and separation (Tb.Sp) were computed.ResultsMDCT-derived BV/TV and Tb.Sp were highly correlated (r = 0.92–0.96, p < 0.0001) with the corresponding HR-pQCT parameters. Tb.Th was the only structure measure that did not yield any significant correlation.ConclusionThe 64- and 320-slice MDCT systems both perform equally well in depicting trabecular bone architecture. However, because of constrained resolutions accurate derivation of trabecular bone measures is limited to only a subset of microarchitectural parameters.

Evaluation of correction methods for coil‐induced intensity inhomogeneities and their influence on trabecular bone structure parameters from MR images

Magnetic resonance (MR) imaging-based quantitative trabecular bone structure analysis has gained increasing interest in osteoporotic fracture risk assessment and treatment evaluation related to osteoporosis. In vivo MR images of anatomic regions such as the proximal femur and distal tibia are generally acquired with a surface coil in order to obtain sufficient sensitivity and resolution for quantification of the trabeculae. However, these coils introduce intensity inhomogeneities which affect the trabecular bone structure analysis. This work evaluates the applicability of a fully automatic coil correction by nonparametric nonuniform intensity normalization (N3) in the analysis of trabecular bone parameters. The ability to correct for coil-induced intensity inhomogeneity was evaluated ex vivo on proximal femur specimens scanned with both a surface coil and a volume coil, which allowed for a direct evaluation of the performance of the coil correction methods without any major confounding factors. In addition, trabecular bone parameter values were correlated with values from high-resolution peripheral computed tomography (HR-pQCT) scans, and the reproducibility of trabecular bone parameters was evaluated in an in vivo study of repeat hip MR scans. The trabecular bone parameters determined from MR surface coil scans processed with the N3 coil correction method showed significant correlation (p < 0.05) with corresponding values from homogeneous intensity data in the ex vivo study. This can be compared to the correlation without coil correction (p < 0.5), and coil correction using low-pass filtering (LPF) (p < 0.53). The in vivo interscan variability was reduced from 8.9% to 12.8% using LPF-based to 3.6%-8.4% (CV) using N3 coil correction; hence the results showed that N3 is advantageous to LPF-based coil correction. No significant differences in correlation to HR-pQCT data were found for the coil correction methods. The significant correlations with volume coil data and high reproducibility of the N3 processed data imply that N3 coil correction preserve image information while accurately correcting for coil-induced intensity inhomogeneities, which makes it suitable for quantitative analysis of trabecular bone structure from MR images acquired with surface coils.

87 Prediction of Hip Fracture Load from Radiographs by Combined Analysis of Trabecular Bone Structure and Bone Geometry

87 Prediction of Hip Fracture Load from Radiographs by Combined Analysis of Trabecular Bone Structure and Bone Geometry

62 Multifractal and Topological Analysis of Trabecular Bone Structure Related to Osteoporosis

62 Multifractal and Topological Analysis of Trabecular Bone Structure Related to Osteoporosis

Trabecular Bone Structure Analysis in the Limited Spatial Resolution Regime of In Vivo MRI

To develop a method for processing and visualization of trabecular bone networks on the basis of magnetic resonance (MR) images acquired in the limited spatial resolution regime of in vivo imaging at which trabecular thickness is comparable to voxel size. A sequence of processing steps for analyzing the topologic structure of trabecular bone networks is presented and evaluated using three types of datasets: images of synthetic structures with various levels of superimposed Gaussian noise, micro-computed tomographic images of human trabecular bone downsampled to in vivo resolution, and in vivo micro-MR images from a prior longitudinal study investigating the structural implications of testosterone treatment of hypogonadal men. The simulated images were analyzed at a voxel size of 150 microm(3), the clinical MR image data had been acquired with 137 x 137 x 410 microm(3) voxel size. The technique is a modification to the virtual bone biopsy processing chain that involves a sinc convolution step immediately preceding binarization, and employs the Manzanera-Bernard thinning algorithm for obtaining the three-dimensional skeleton before topologic classification. The detectability of plate and rod bone elements was also analyzed theoretically. As compared with previously published techniques, the approach produced a more accurate bone skeleton in the micro-computed tomographic and simulation experiments, with clear improvement in preservation of rod and plate elements. Simulations suggest that rods are detectable down to a diameter of approximately 50% of the MR image voxel length, whereas plates can be detected at thicknesses of 20% or more of voxel length. For in vivo studies, it was shown that the method could recover the treatment response in terms of the ensuing topologic changes in patients undergoing antiresorptive treatment. The algorithm for processing of in vivo micro-MR images of trabecular bone is superior to prior approaches in preserving the topology of the network in the presence of noise.

Experimental hip fracture load can be predicted from plain radiography by combined analysis of trabecular bone structure and bone geometry

Computerized analysis of the trabecular structure was used to test whether femur failure load can be estimated from radiographs. The study showed that combined analysis of trabecular bone structure and geometry predicts in vitro failure load with similar accuracy as DXA. Since conventional radiography is widely available with low imaging cost, it is of considerable interest to discover how well bone mechanical competence can be determined using this technology. We tested the hypothesis that the mechanical strength of the femur can be estimated by the combined analysis of the bone trabecular structure and geometry. The sample consisted of 62 cadaver femurs (34 females, 28 males). After radiography and DXA, femora were mechanically tested in side impact configuration. Fracture patterns were classified as being cervical or trochanteric. Computerized image analysis was applied to obtain structure-related trabecular parameters (trabecular bone area, Euler number, homogeneity index, and trabecular main orientation), and set of geometrical variables (neck-shaft angle, medial calcar and femoral shaft cortex thicknesses, and femoral neck axis length). Multiple linear regression analysis was performed to identify the variables that best explain variation in BMD and failure load between subjects. In cervical fracture cases, trabecular bone area and femoral neck axis length explained 64% of the variability in failure loads, while femoral neck BMD also explained 64%. In trochanteric fracture cases, Euler number and femoral cortex thickness explained 66% of the variability in failure load, while trochanteric BMD explained 72%. Structural parameters of trabecular bone and bone geometry predict in vitro failure loads of the proximal femur with similar accuracy as DXA, when using appropriate image analysis technology.

Analysis of Trabecular Bone Structure with Multidetector Spiral Computed Tomography in a Simulated Soft-Tissue Environment

We investigated the influence of soft tissue (ST) on image quality by high-resolution multidetector computed tomography (MDCT) scans and assessed the effect of surrounding ST on the quantification of trabecular bone structure. Eight bone cores obtained from human proximal femoral heads discarded during hip replacement surgery were scanned with micro-computed tomography (microCT) as well as with MDCT both without (w/o) and with (w) simulated surrounding ST, where a phantom imitated a human torso. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were measured in all scans. Apparent trabecular bone structure parameters were calculated and compared to similar parameters obtained in coregistered sections of the microCT scans. Residual errors were calculated as root-mean-square (RMS) errors relative to the microCT measurements. Compared to microCT results, trabecular structure parameters were overestimated by MDCT both w and w/o ST. SNR and CNR were significantly higher in the scans w/o ST. Significant correlations between microCT and MDCT results were found for bone fraction (r = 0.90 w/o ST, r = 0.84 w ST), trabecular number, and separation. RMS ranged from 10% to 15% for MDCT w/o ST and from 10% to 17% for MDCT w ST. Only bone fraction showed significantly different RMS and correlations for scans w/o vs. w ST (P < 0.05). This study showed that MDCT is able to visualize trabecular bone structure in an in vivo-like setting at skeletal sites within the torso such as the proximal femur. Even though ST scatter compromises image quality substantially, the major characteristics of the trabecular network can still be appreciated and quantified.

Identification of hip fracture patients from radiographs using Fourier analysis of the trabecular structure: a cross-sectional study

BackgroundThis study presents an analysis of trabecular bone structure in standard radiographs using Fourier transforms and principal components analysis (PCA) to identify contributions to hip fracture risk.MethodsRadiographs were obtained from 26 hip fracture patients and 24 controls. They were digitised and five regions of interest (ROI) were identified from the femoral head and neck for analysis. The power spectrum was obtained from the Fourier transform of each region and three profiles were produced; a circular profile and profiles parallel and perpendicular to the preferred orientation of the trabeculae. PCA was used to generate a score from each profile, which we hypothesised could be used to discriminate between the fracture and control groups. The fractal dimension was also calculated for comparison. The area under the receiver operating characteristic curve (Az) discriminating the hip fracture cases from controls was calculated for each analysis.ResultsTexture analysis of standard radiographs using the fast Fourier transform yielded variables that were significantly associated with fracture and not significantly correlated with age, body mass index or femoral neck bone mineral density. The anisotropy of the trabecular structure was important; both the perpendicular and circular profiles were significantly better than the parallel-profile (P < 0.05). No significant differences resulted from using the various ROI within the proximal femur. For the best three groupings of profile (circular, parallel or perpendicular), method (PCA or fractal) and ROI (Az = 0.84 – 0.93), there were no significant correlations with femoral neck bone mineral density, age, or body mass index. PCA analysis was found to perform better than fractal analysis (P = 0.019).ConclusionsBoth PCA and fractal analysis of the FFT data could discriminate successfully between the fracture and control groups, although PCA was significantly stronger than fractal dimension. This method appears to provide a powerful tool for the assessment of bone structure in vivo with advantages over standard fractal methods.