Trabecular bone score (TBS) in the assessment of bone microarchitecture in acromegaly

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Caractérisation et modélisation de la hanche chez l'enfant par IRM (application à la maladie de Legg-Calvé-Perthes)

La maladie de Legg-Calvé-Perthes touche un grand nombre d'enfants, principalement des garçons. Cette maladie résulte d'une absence de vascularisation de l'épiphyse fémorale et se définit comme une ischémie vasculaire provoquant d'importants problèmes biomécaniques. C'est dans ce contexte clinique que s'inscrit ce travail concernant la caractérisation et la modélisation de la hanche, de manière à mieux connaître l'aspect de l'articulation aux différents stades de la maladie et à pouvoir trouver des facteurs objectifs donnant une classification prospective de la maladie. Pour cela, deux approches complémentaires ont été abordées: une approche biomécanique modélisant l'articulation et évaluant les rapports de forces mécaniques appliquées sur cette articulation; et une approche par traitement d'images, permettant l'obtention de la géométrie de l'articulation, la quantification biomécanique des différents tissus articulaires et la vascularisation de la tête fémorale.Legg-Calvé-Perthes disease is defined as an idiopathic avascular necrosis of the femoral epiphysis leading to biomechanical disorders. It affects a number of children, more frequently boys. It is in this clinical context that our study characterizes and models the hip. This study has been performed to better understand the various stages of the disease and the objective factors to identify the prospective classification of the disease. For this, two complementary approaches were elaborated: a biomechanical approach modelling the articulation and evaluating the applied mechanical stress; and an image processing approach, allowing to obtain the joint geometry, the biomechanical characterization of the joint tissues and the vascularization of the femoral head.COMPIEGNE-BU (601592101) / SudocSudocFranceF

Proximal Femur Responses to Sequential Therapy With Abaloparatide Followed by Alendronate in Postmenopausal Women With Osteoporosis by 3D Modeling of Hip Dual-Energy X-Ray Absorptiometry (DXA)

Previous subgroup analyses from the ACTIVE trial in women with postmenopausal osteoporosis (NCT01343004) using three-dimensional (3D)-processing of dual X-ray absorptiometry (DXA) scans indicated greater increases in total hip cortical volumetric bone mineral density (Ct.vBMD) and estimated indices of hip strength following 18 months of abaloparatide (ABL) versus placebo or teriparatide. The current post hoc analyses describe hip 3D-DXA data for ACTIVExtend (NCT01657162), in which 18 months of ABL followed by 24 months of alendronate (ABL/ALN) increased hip and spine areal BMD (aBMD) and reduced fracture risk versus placebo (PBO) followed by ALN (PBO/ALN). In an ACTIVExtend subgroup (ABL/ALN, n = 204; PBO/ALN, n = 202), hip DXA scans retrospectively underwent 3D modeling via 3D-Shaper software. Changes from baseline in cortical and trabecular compartments were calculated for total hip and hip subregions (femoral neck, trochanter, and shaft). Estimated strength indices comprising cross-sectional moment of inertia, section modulus, and buckling ratio were calculated for each hip subregion. Correlations between bone turnover marker levels at the time of alendronate initiation and subsequent BMD gains with alendronate were also investigated within each group. Total hip trabecular and cortical 3D-DXA parameters increased from baseline in both groups (all p < 0.001), with greater average increases for ABL/ALN versus PBO/ALN (trabecular vBMD: 10.87% versus 4.3%; cortical thickness: 2.32% versus 1.14%; Ct.vBMD: 3.41% versus 1.86%; cortical surface BMD: 5.82% versus 3.0%; all p < 0.001). Strength indices in the ABL/ALN group improved in all subregions versus baseline (all p < 0.0001) and versus PBO/ALN (all p < 0.02). In the ABL/ALN group, collagen type I N-terminal propeptide (P1NP) levels at the time of alendronate initiation correlated with subsequent percent changes in all 3D-DXA parameters with 24 months of alendronate therapy. In conclusion, sequential ABL/ALN or PBO/ALN treatment improves trabecular and cortical 3D-DXA parameters at the hip, as well as strength indices of hip subregions, with greater increases with ABL/ALN versus PBO/ALN. © 2022 Radius Health, Inc. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.Mid-coronal sections of the hip depict mean changes in volumetric BMD. Greater increases in cortical regions are shown by more green color for participants who received sequential therapy with abaloparatide followed by alendronate versus those who received placebo followed by alendronate.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/172340/1/jbm410612.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/172340/2/jbm410612_am.pd

TBS as a Tool to Differentiate the Impact of Antiresorptives on Cortical and Trabecular Bone in Children With Osteogenesis Imperfecta

Introduction/Background: Osteogenesis imperfecta is a hereditary connective tissue disorder, resulting in low bone mass and high bone fragility. Dual-energy X-ray absorptiometry (DXA) and in adulthood also the trabecular bone score (TBS) are well established to assess bone health and fracture risk. The purpose of this investigation was to assess the usefulness of TBS in respect to different treatment regimes in children with osteogenesis imperfecta. Changes of areal bone mineral density (aBMD) and TBS using DXA scans of children treated with antiresorptive therapies were evaluated. Methodology: DXA scans (aBMD, TBS) of 8 children with CM were evaluated. The scans were taken during a 1 yr period of treatment with bisphosphonates and during 1 yr pilot trial using denosumab. Changes of aBMD and TBS during both treatment regimens were compared. Results: During bisphosphonate treatment aBMD increased about 6.2%, while TBS increased about 2.1%. The difference between aBMD and TBS before and after bisphosphonate treatment was not significant (p = 0.25). During denosumab treatment aBMD increased around 25.1%, while TBS increased 6.7%. The change of aBMD was significant (p = 0.007), as was the difference between aBMD and TBS (p < 0.001). Conclusions: Denosumab had a significant effect on both aBMD and TBS but was significantly more pronounced in aBMD. These results suggest a stronger effect of denosumab on cortical bone and the growth plate in comparison to bisphosphonates. Beside the lack of paediatric reference data and the small sample size, the results suggest TBS to be a useful tool for monitoring skeletal changes during development, growth, and antiresorptive therapy in children with OI

Creation of an age-adjusted, dual-energy x-ray absorptiometry-derived trabecular bone score curve for the lumbar spine in non-hispanic US white women

The trabecular bone score (TBS, Med-Imaps, Pessac, France) is an index of bone microarchitecture texture extracted from anteroposterior dual-energy X-ray absorptiometry images of the spine. Previous studies have documented the ability of TBS of the spine to differentiate between women with and without fractures among age- and areal bone mineral density (aBMD)-matched controls, as well as to predict future fractures. In this cross-sectional analysis of data collected from 3 geographically dispersed facilities in the United States, we investigated age-related changes in the microarchitecture of lumbar vertebrae as assessed by TBS in a cohort of non-Hispanic US white American women. All subjects were 30 yr of age and older and had an L1–L4aBMDZ-score within ±2 SD of the population mean. Individuals were excluded if they had fractures, were on any osteoporosis treatment, or had any illness that would be expected to impact bone metabolism. All data were extracted from Prodigy dual-energy X-ray absorptiometry devices (GE-Lunar, Madison, WI). Cross-calibrations between the 3 participating centers were performed for TBS and aBMD. aBMD and TBS were evaluated for spine L1–L4 but also for all other possible vertebral combinations. To validate the cohort, a comparison between the aBMD normative data of our cohort and US non-Hispanic white Lunar data provided by the manufacturer was performed. A database of 619 non-Hispanic US white women, ages 30–90 yr, was created. aBMD normative data obtained from this cohort were not statistically different from the non-Hispanic US white Lunar normative data provided by the manufacturer (p = 0.30). This outcome thereby indirectly validates our cohort. TBS values at L1–L4 were weakly inversely correlated with body mass index (r = −0.17) and weight (r = −0.16) and not correlated with height. TBS values for all lumbar vertebral combinations decreased significantly with age. There was a linear decrease of 16.0% (−2.47 T-score) in TBS at L1–L4 between 45 and 90 yr of age (vs. −2.34 for aBMD). Microarchitectural loss rate increased after age 65 by 50% (−0.004 to −0.006). Similar results were obtained for other combinations of lumbar vertebra. TBS, an index of bone microarchitectural texture, decreases with advancing age in non-Hispanic US white women. Little change in TBS is observed between ages 30 and 45. Thereafter, a progressive decrease is observed with advancing age. The changes we observed in these American women are similar to that previously reported for a French population of white women (r2 > 0.99). This reference database will facilitate the use of TBS to assess bone microarchitectural deterioration in clinical practice

Bone age as a correction factor for the analysis of trabecular bone score (TBS) in children

Summary Trabecular bone score (TBS) is a tool to improve evaluation of DXA scans, barely used in children. We proposed to evaluate TBS with bone age (BA) compared to chronological age (CA). In girls, TBS value using BA is constant until age 8, and in boys until age 10, and then starts to increase steadily. This data may help widen TBS use in pediatric populations. Introduction Trabecular bone score (TBS) is a software-based tool for the analysis of DXA images to assess bone microarchitecture in the lumbar region. It is used widely in adults to improve evaluation of fracture risk, yet it has been rarely studied in children and no normal curves have been developed for pediatrics. The purpose of this study was to evaluate bone (skeletal) age compared to chronological age to determine which is better in the pediatric population since both bone age (BA) and trabecular density are equally susceptible to change in response to similar factors. Methods Total body, lumbar region, and non-dominant hand scans were obtained with an iDXA device in all participants. DXA scans of lumbar region for TBS analysis and AP images of non-dominant hand-for-BA were obtained for 565 children (269 female) aged 4to 19. Results Simple correlation was calculated and r2 values for TBS and chronological age were obtained by linear regression, with low correlations (0.36 for boys and 0.38 for girls), and then we created Loess curves to show the change for consecutive ages. In girls, the curve forms a U shape with a nadir point at approximately age 10. We then replaced chronological age with BA, and significant change was seen in the girls’ curve, where a turning point is seen at age 8. In boys, a similar trend shows a turning point at age 10. Finally, BA-corrected TBS curves were constructed using LMS, obtaining curves with percentiles. Conclusions The use of BA in the analysis and interpretation of TBS may help widen its use in pediatric populations by enabling the appearance of normative data, but more information is needed to confirm this finding

Bone Microarchitecture Assessed by Trabecular Bone Score Is Independent of Mobility Level or Height in Pediatric Patients with Cerebral Palsy

Bone strength and fracture risk do not only depend on bone density, but also on bone structure. The trabecular bone score (TBS) evaluates homogeneity of bone microarchitecture indirectly by measuring gray-level variations of two-dimensional (2D) DXA images. Although TBS is well-established for adults, there have been only few publications in pediatrics. In this monocentric retrospective analysis, we investigated TBS in children and adolescents with cerebral palsy (CP), a patient group vulnerable to low bone mineral mass due to impaired mobility. The influence of different parameters on TBS and areal BMD (aBMD) were evaluated, as well as the relationship between TBS and aBMD. We compared TBS values of our study population to a reference population. A total of 472 lumbar spine-dual-energy X-ray absorptiometry (LS-DXA) scans of children and adolescents with CP (205 female), aged between 4 and 18 years, were analyzed. The DXA-scans were part of the routine examination. The children had no records of fractures or specific bone diseases. Our study population with CP had similar TBS as the reference population. TBS did not increase with age until an inflection point at 10 years in females, and 12 years in males. Girls had significantly higher TBS than boys (p = .049) and pubertal girls aged 8 to 13 years had significantly higher TBS than prepubertal girls (p = .009). TBS standard deviation score for age (SDS-TBS) and aBMD Z-scores correlated weakly (p < .001; R = 0.276 [males], R = 0.284 [females]). Other than for aBMD Z-scores, SDS-TBS was not influenced by age-adjusted height Z-scores and there was no significant difference in SDS-TBS when grouped by mobility levels, using the Gross Motor Function Classification System (GMFCS). Our results indicate that children with CP have a similar homogeneous distribution of trabecular microarchitecture as controls. Puberty initiation appears to be essential for increase of TBS with age and for sex differences. TBS seems less influenced by body composition, height, and mobility than aBMD. (c) 2020 American Society for Bone and Mineral Research