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Example of images provided by DXA: BMD L1L4 = 0.868 g/cm² (left); TBS L1-L4 = 1.361 (center) and BSI L1L4 = 1.57 (right).
Source publication
For a proper assessment of osteoporotic fragility fracture prediction, all aspects regarding bone mineral density, bone texture, geometry and information about strength are necessary, particularly in endocrinological and rheumatological diseases, where bone quality impairment is relevant. Data regarding bone quantity (density) and, partially, bone...
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Background
Several retrospective studies have reported spine–femur discordance in bone mineral density (BMD) values. However, the average age of individuals in these studies was the mid-50s, which is younger than the typical age of individuals requiring treatment for primary osteoporosis. Therefore, we aimed to investigate factors associated with d...
Citations
... Lumbar BSI was calculated using the dedicated version of Bone Strain Index software (Tecnologie Avanzate T.A. s.r.l., Torino, Italy) modified for specific use in subjects with kyphosis and the analysis was based on a mathematical approach called the Finite Element Method, relying on geometric and material information extrapolated from DXA images [21]. In particular, bone geometry followed the segmentation analysis performed by DXA software on the greyscale image, and it was based on the same regions of interest defined by the DXA operator (i.e., L1-L4 area for lumbar scans). ...
Purpose
The bone strain index (BSI) is a marker of bone deformation based on a finite element analysis inferred from dual X-ray absorptiometry (DXA) scans, that has been proposed as a predictor of fractures in osteoporosis (i.e., higher BSI indicates a lower bone’s resistance to loads with consequent higher risk of fractures). We aimed to investigate the association between lumbar BSI and vertebral fractures (VFs) in acromegaly.
Methods
Twenty-three patients with acromegaly (13 males, mean age 58 years; three with active disease) were evaluated for morphometric VFs, trabecular bone score (TBS), bone mineral density (BMD) and BSI at lumbar spine, the latter being corrected for the kyphosis as measured by low-dose X-ray imaging system (EOS®-2D/3D).
Results
Lumbar BSI was significantly higher in patients with VFs as compared to those without fractures (2.90 ± 1.46 vs. 1.78 ± 0.33, p = 0.041). BSI was inversely associated with TBS (rho −0.44; p = 0.034), without significant associations with BMD (p = 0.151), age (p = 0.500), BMI (p = 0.957), serum IGF-I (p = 0.889), duration of active disease (p = 0.434) and sex (p = 0.563).
Conclusions
Lumbar BSI corrected for kyphosis could be proposed as integrated parameter of spine arthropathy and osteopathy in acromegaly helping the clinicians in identifying patients with skeletal fragility possibly predisposed to VFs.
... Osteoporosis represents a skeletal disorder characterised by reduced bone strength that leads to an increased fracture risk [1,2]. Bone strength is mainly determined by bone mineral density (BMD), bone micro-architecture and the ability of bone to deform under loads [3]. The quantitative evaluation of BMD, based on dual-energy X-ray absorptiometry (DXA), is the reference standard in clinical routine [4]. ...
... The quantitative evaluation of BMD, based on dual-energy X-ray absorptiometry (DXA), is the reference standard in clinical routine [4]. It has been shown that the risk of fracture doubles for one standard deviation reduction in BMD measured using DXA, as density and failure of a loaded material have a quadratic relationship [3,5]. However, BMD alone may lack sensitivity for individual fracture risk assessment, as many patients presenting with an incident or prevalent fragility fracture show BMD values in the osteopenic range [6]. ...
... However, BMD alone may lack sensitivity for individual fracture risk assessment, as many patients presenting with an incident or prevalent fragility fracture show BMD values in the osteopenic range [6]. Indeed, BMD cannot evaluate the above-mentioned bone strength determinants: bone texture and bone deformation capability [3,7]. Other radiological indexes based on DXA have been proposed to enhance fracture prediction. ...
Bone Strain Index (BSI), based on dual-energy X-ray absorptiometry (DXA), is a densitometric index of bone strength of the femur and lumbar spine. Higher BSI values indicate a higher strain applied to bone, predisposing to higher fracture risk. This retrospective, multicentric study on Italian women reports the BSI normative age-specific reference curves. A cohort of Caucasian Italian women aged 20 to 90 years was selected from three different clinical centres. Bone mineral density (BMD) and BSI measurements were obtained for the lumbar spine vertebrae (L1–L4) and for the femur (neck, trochanter and intertrochanter) using Hologic densitometers scans. The data were compared with BMD normative values provided by the densitometer manufacturer. Then, the age-specific BSI curve for the femur and lumbar spine was generated. No significant difference was found between the BMD of the subjects in this study and BMD reference data provided by Hologic (p = 0.68 for femur and p = 0.90 for lumbar spine). Spine BSI values (L1–L4) increase by 84% between 20 and 90 years of age. The mean BSI of the total femur increases about 38% in the same age range. The BSI age-specific reference curve could help clinicians improve osteoporosis patient management, allowing an appropriate patient classification according to the bone resistance to the applied loads and fragility fracture risk assessment.
... The underlying assumption of the BSI is that an increase in fracture risk is proportional to an increase in strain. Using this approach, bone fragility is no longer based solely on mineral content or geometry but incorporates the quality of the bone matrix [32]. Although the BSI is a new index, the first results are promising and confirm, as suggested by Hart in 2017 [33], the necessity to consider the organic phase of the bone, which is typically not considered in clinical investigations. ...
The mechanical properties of bone tissue are the result of a complex process involving collagen–crystal interactions. The mineral density of the bone tissue is correlated with bone strength, whereas the characteristics of collagen are often associated with the ductility and toughness of the bone. From a clinical perspective, bone mineral density alone does not satisfactorily explain skeletal fragility. However, reliable in vivo markers of collagen quality that can be easily used in clinical practice are not available. Hence, the objective of the present study is to examine the relationship between skin surface morphology and changes in the mechanical properties of the bone. An experimental study was conducted on healthy children (n = 11), children with osteogenesis imperfecta (n = 13), and women over 60 years of age (n = 22). For each patient, the skin characteristic length (SCL) of the forearm skin surface was measured. The SCL quantifies the geometric patterns formed by wrinkles on the skin’s surface, both in terms of size and elongation. The greater the SCL, the more deficient was the organic collagen matrix. In addition, the bone volume fraction and mechanical properties of the explanted femoral head were determined for the elderly female group. The mean SCL values of the healthy children group were significantly lower than those of the elderly women and osteogenesis imperfecta groups. For the aged women group, no significant differences were indicated in the elastic mechanical parameters, whereas bone toughness and ductility decreased significantly as the SCL increased. In conclusion, in bone collagen pathology or bone aging, the SCL is significantly impaired. This in vivo skin surface parameter can be a non-invasive tool to improve the estimation of bone matrix quality and to identify subjects at high risk of bone fracture.
... The International Society for Clinical Densitometry (ISCD) diagnostic criteria for osteoporosis include a comparison with the BMD reference value for White women aged 20-29 years, called the T-score, with scores required to be within 2.5 standard deviations (SD). Osteopenia refers to a bone density T-score between −1 and −2.5 (3)(4)(5). However, some patients with osteoporotic fractures only show osteopenia on BMD measurements, which does not meet the diagnostic criteria for osteoporosis, or the BMD measurement may be within the normal range, suggesting that other factors also affect bone strength (6). ...
... BMD (L 1-4 ) and TBS (L 1-4 ) were also higher in men than in women (P<0.001). Age was negatively correlated with TBS (L [1][2][3][4] and BMD (L 1-4 ) in men and in women (P<0.001). TBS (L 1-4 ) showed a significant positive correlation with BMD (L 1-4 ) in both sexes, with the correlation of TBS and BMD being stronger in women than in men (0.78 vs. 0.65; P<0.001). ...
Background:
Trabecular bone score (TBS) is a relatively new gray-level textural parameter that provides information on bone microarchitecture. TBS has been shown to be a good predictor of fragility fractures independent of bone density and clinical risk factors. Estimating the normal reference values of TBS in both sexes among the Chinese population is necessary to improve the clinical fracture risk assessment.
Methods:
This retrospective study enrolled healthy Chinese participants living in Guangzhou, China, including 1,018 men and 3,061 women (aged 20-74 years). Bone mineral density images were obtained with dual-energy X-ray absorptiometry (DXA) scanning of the lumbar region (L1-4). Lumbar spine TBS values were calculated. The correlations between the scores and bone mineral density, age, height, and weight were calculated for men and women. A TBS reference plot was established in relation to age (20-74 years). Values 2 standard deviations below the mean score for each sex were used as the cutoff values for low-quality bone.
Results:
The TBS (L1-4) was significantly higher in Chinese men than in Chinese women. The scores peaked at 25-29 years (1.47±0.08 years) in men and at 20-24 years (1.43±0.08 years) in women. According to the statistical confidence interval, in Chinese males, a TBS ≥1.39 is considered normal, a TBS between 1.31 and 1.39 indicates partially degraded microarchitecture, and a TBS ≤1.31 indicates degraded microarchitecture. In Chinese females, a TBS ≥1.35 is considered normal, a TBS between 1.27 and 1.35 indicates partially degraded microarchitecture, and a TBS ≤1.27 indicates degraded microarchitecture.
Conclusions:
This study provides normative reference ranges for the TBS in Chinese men and women. Chinese men with a TBS score ≤1.31 and Chinese women with a TBS score ≤1.27 are can be considered to have reduced bone microarchitecture and may be at higher risk of having osteoporosis fractures.
... The BSi can be derived from both lumbar and femoral dXa scans and higher BSi values indicate lower bone strength. 80 The literature demonstrated the utility of BSi in the detection of primary and secondary osteoporosis, monitoring anabolic treatment, and prediction of fragility fractures. 81 The cross-sectional study by Tabacco et al. 82 was the first study that evaluated BSI in patients with PhPT. ...
Bone involvement in primary hyperparathyroidism (PHPT) is characterized by reduced bone mineral density (BMD) using dual X-Ray absorptiometry (DXA). A hallmark of PHPT is BMD loss at cortical sites while trabecular bone remains relatively preserved. PHPT is associated with increased fracture risk at both trabecular and cortical skeletal sites, which cannot be explained based on BMD values alone. The application of the trabecular bone score (TBS), an index of the lumbar spine DXA bone microarchitecture, showed lower TBS values and increased risk of fractures in PHPT patients, independent of BMD. Although further prospective studies are needed, promising data have been published with the use of TBS and some advanced DXA-based imaging modalities in patients with PHPT.
... Assessment of bone derangement is based on dual-energy X-ray absorptiometry (DEXA) to measure BMD. BMD is unquestionably one of the most important determinants of bone quality and the World Health Organization (WHO) diagnostic classification of osteoporosis is based on its values as expressed in T scores [3,7,8]. Patients with CS are reported to have a 60% to 80% prevalence of osteopenia and a 30% to 65% prevalence of osteoporosis, respectively [1,9,10]. ...
... These models rely on the principle that complex objects can be simplified by transforming them into smaller elements (the "finite element"), to be used for simulating any specific phenomenon. 13 In the setting of bone strength analysis, FEA has been already applied to several imaging techniques, such as CT, QCT, and high-resolution peripheral CT/MRI, with the aim of analyzing images to identify those bone areas subject to higher mechanical stress, therefore to higher fracture risk. 13 The BSI calculation is directly obtained from DXA images through specific software and can be currently applied both on the lumbar spine and femoral scan. ...
... 13 In the setting of bone strength analysis, FEA has been already applied to several imaging techniques, such as CT, QCT, and high-resolution peripheral CT/MRI, with the aim of analyzing images to identify those bone areas subject to higher mechanical stress, therefore to higher fracture risk. 13 The BSI calculation is directly obtained from DXA images through specific software and can be currently applied both on the lumbar spine and femoral scan. The software creates a FEA model by dividing the DXA area into small triangles according to the mapping contour of the DXA image. ...
... The load applied to the upper plate is obtained starting from patient-specific simulated forces in a standing position, also based on weight and height. 13 In the femur, BSI is calculated assuming the event of a lateral fall, with the simulated force applied to the greater trochanter and the constraints applied at the level of the femoral head and shaft. 13 The final BSI value represents the average bone equivalent strain, assuming that the higher the BSI, the higher the strain level and therefore the fracture risk. ...
Metabolic bone diseases comprise a wide spectrum. Of them, osteoporosis is the most frequent and the most commonly found in the spine, with a high impact on health care systems and on morbidity due to vertebral fractures (VFs).
This article discusses state-of-the-art techniques on the imaging of metabolic bone diseases in the spine, from the well-established methods to the latest improvements, recent developments, and future perspectives.
We review the classical features of involvement of metabolic conditions involving the spine. Then we analyze the different imaging techniques for the diagnosis, characterization, and monitoring of metabolic bone disease: dual-energy X-ray absorptiometry (DXA) and DXA-based fracture risk assessment applications or indexes, such as the geometric parameters, Bone Strain Index, and Trabecular Bone Score; quantitative computed tomography; and magnetic resonance and ultrasonography-based techniques, such as radiofrequency echographic multi spectrometry. We also describe the current possibilities of imaging to guide the treatment of VFs secondary to metabolic bone disease.
... Bone Strain Index (BSI) was calculated from LS DXA scans to provide evidence of the average equivalent strain inside the bone, with the assumption that a higher strain level (high BSI) stands for a more significant risk condition [21]. ...
Background
Delayed puberty is a possible complication of Epidermolysis Bullosa (EB), though the actual incidence is still unknown. In chronic illnesses delayed puberty should be correctly managed since, if untreated, can have detrimental effects on adult height attainment, peak bone mass achievement and psychological health.
Aims and methods
This is a single-centre study on pubertal development, growth and bone status in EB. Auxological, densitometric (areal Bone Mineral Density-aBMD Z-score, Bone Mineral Apparent Density-BMAD Z-score, Trabecular Bone Score-TBS and Bone Strain Index-BSI at Lumbar spine) and body composition data (Total Body DXA scans) were collected. Disease severity was defined according to Birmingham Epidermolysis Bullosa Severity (BEBS) score.
Results
Twenty-one patients (12 Recessive Dystrophic EB-RDEB, 3 Dominant Dystrophic EB, 3 Junctional EB-JEB, 2 EB Simplex and one Kindler EB) aged 13 years (females) or 14 years (males) and above were enrolled (age 16.2±2.5 years, M/F 11/10). Short stature was highly prevalent (57%, mean height -2.12±2.05 SDS) with 55% patients with height <-2SD their mid-parental height. 7/21 patients (33%, 6 RDEB and 1 JEB) had delayed puberty with a median BEBS of 50 (range 29 to 63), a height SDS of -2.59 SDS (range -5.95 to -2.22) and a median lumbar BMAD Z-score of -4.0 SDS (range -5.42 to -0.63 SDS). Pubertal status was negatively associated with BEBS, skin involvement, inflammatory state and positively with height SDS and BMI SDS.
Conclusions
Pubertal delay is highly prevalent in EB, especially in patients with RDEB and JEB, high severity score and inflammatory state. Moreover, pubertal delay worsens growth impairment and bone health. A study on pubertal induction is ongoing to enlighten possible beneficial effects on adult height attainment and peak bone mass accrual.
... The quantitative evaluation of bone mineral density (BMD) is routinely done in clinical practice using dual-energy X-ray absorptiometry (DXA), a technique considered the reference standard in clinical routine [4]. Bone strength is mainly related to BMD values, and it has been shown how the risk of fracture doubles for each standard deviation reduction in BMD, due to the relation between density and failure of a loaded material [5,6]. However, BMD by DXA may lack sensitivity for individual fracture risk assessment, as many patients presenting with incident or prevalent fragility fractures show non-osteoporotic BMD values [7]. ...
... However, BMD by DXA may lack sensitivity for individual fracture risk assessment, as many patients presenting with incident or prevalent fragility fractures show non-osteoporotic BMD values [7]. Indeed, BMD is not able to evaluate other bone strength determinants like bone texture and geometry, in addition to other microarchitectural parameters [6,8]. Other radiological indexes based on DXA 1 3 have been proposed to improve fracture risk prediction. ...
... In 2021, a novel DXAbased bone software has been developed and introduced in clinical practice with the name of Bone Strain Index (BSI), manufactured by Tecnologie Avanzate (Tecnologie Avanzate T.A. S.r.l., Torino, Italy) [14]. It represents an index of deformation based on finite element analysis and can be automatically calculated from DXA exams [6,15]. Previous studies showed the utility of BSI in the identification of subjects with high fracture risk [16], for fracture risk prediction [17,18], for re-fracture prediction and for further characterization of young patients suffering secondary forms of osteoporosis [19,20]. ...
PurposeBone Strain Index (BSI) is a recently developed dual-energy X-ray absorptiometry (DXA) software, applying a finite element analysis on lumbar spine and femoral DXA scans. BSI is a parameter of bone deformation, providing information on bone resistance to applied loads. BSI values indicate the average bone strain in the explored site, where a higher strain (higher BSI values) suggests a higher fracture risk. This study reports the distributional characteristics of lumbar BSI (L-BSI) in women with normal bone mass, osteopenia or osteoporosis and their relationships with BMD, weight, height and BMI.Material and methodsTwo-hundred-fifty-nine consecutive unfractured women who performed DXA were divided into three groups based on BMD T-score: normal bone mass (n = 43, 16.6%), osteopenia (n = 82, 31.7%) and osteoporosis (n = 134, 51.7%). The distribution of L-BSI was evaluated with conventional statistical methods, histograms and by calculating parametric and nonparametric 95% confidence intervals, together with the 90%, 95% and 99% bilateral tolerance limits with a 95% confidence.ResultsNinety percent bilateral tolerance limits with 95% confidence for L-BSI distribution are 1.0–2.40, 0.95–2.63 and 0.84–3.15 in the group of patients with normal bone mass, 1.34–2.78, 1.24–2.95 and 1.05–3.32 in the osteopenic group and 1.68–3.79, 1.58–4.15 and 1.40–4.96 in the osteoporotic group.Conclusion
In women without vertebral fractures at baseline, L-BSI values from 1.68 (osteoporotic group) and 2.40 (upper of the normal bone mass group) can be tentatively chosen as a lower and upper threshold to stratify postmenopausal women according to their bone resistance to loads.
... Diminished BMD results in osteoporosis, osteopenia, and increased risk of insufficiency/osteoporotic fractures including fractures of the spine, forearm, hips and calcaneus [5e10]. Dual-energy X-ray absorptiometry (DXA) is considered the gold standard for measuring BMD and for the diagnosis of osteoporosis and osteopenia [11]. DXA BMD measurements are typically obtained at the L1-L4 lumbar spine, femoral neck, and total hip [12]. ...
Objectives
To use the computed tomography (CT) attenuation of the foot and ankle bones for opportunistic screening for osteoporosis.
Methods
Retrospective study of 163 consecutive patients from a tertiary care academic center who underwent CT scans of the foot or ankle and dual-energy X-ray absorptiometry (DXA) within 1 year of each other. Volumetric segmentation of each bone of the foot and ankle was done to obtain the mean CT attenuation. Pearson's correlations were used to correlate the CT attenuations with each other and with DXA measurements. Support vector machines (SVM) with various kernels and principal components analysis (PCA) were used to predict osteoporosis and osteopenia/osteoporosis in training/validation and test datasets.
Results
CT attenuation measurements at the talus, calcaneus, navicular, cuboid, and cuneiforms were correlated with each other and positively correlated with BMD T-scores at the L1-4 lumbar spine, hip, and femoral neck; however, there was no significant correlation with the L1-4 trabecular bone scores. A CT attenuation threshold of 143.2 Hounsfield units (HU) of the calcaneus was best for detection of osteoporosis in the training/validation dataset. SVMs with radial basis function (RBF) kernels were significantly better than the PCA model and the calcaneus for predicting osteoporosis in the test dataset.
Conclusions
Opportunistic screening for osteoporosis is possible using the CT attenuation of the foot and ankle bones. SVMs with RBF using all bones is more accurate than the CT attenuation of the calcaneus.
