Spine Dual-energy X-ray Absorptiometry Research Articles

Opportunistic use of dual-energy X-ray absorptiometry to evaluate lumbar scoliosis.

Osteoporosis and scoliosis are interrelated disease processes. Dual-energy X-ray absorptiometry (DXA), used to assess bone density, can also be used to evaluate spinal deformity since it captures a posteroanterior (PA) image of the lumbar spine. We assessed the use of DXA to evaluate lumbar spine alignment. A lumbar spine DXA phantom was used to assess the effects of axial and sagittal plane rotation on lumbar bone mineral content (BMC), density (BMD), and L1-L4 Cobb angle measurements. Using two subject cohorts, intra- and inter-observer reliability and validity of using DXA for L1-L4 Cobb angle measurements in the coronal and sagittal planes were assessed. Axial and sagittal plane rotation greater than 15° and 10°, respectively, significantly reduced measured BMD and BMC; there was minimal effect on Cobb angle measurement reliability. In human subjects, excellent intra- and inter-observer reliability was observed using lumbar PA DXA images for Cobb angle measurements. Agreement between Cobb angles derived from lumbar PA DXA images and AP lumbar radiographs ranged from good to excellent. The mean difference in Cobb angles between supine lumbar PA DXA images and upright AP lumbar radiographs was 2.8° in all subjects and 5.8° in those with scoliosis. Lumbar spine rotation does not significantly affect BMD and BMC within 15° and 10° of axial and sagittal plane rotation, respectively, and minimally affects Cobb angle measurement. Spine alignment in the coronal plane can be reliably assessed using lumbar PA DXA images.

Reliability of the assessment of disc degeneration on the lateral DXA scans.

Given the prevalence and costs induced by osteoarthritis (OA), it is necessary to find a cheap and safe technique to evaluate it reliably. To assess the value of the lateral dual energy X-ray absorptiometry (DXA) spine scans for the diagnosis of disc degeneration. Seventy-seven individuals aged 18 and over, with or without disc degeneration, had both lateral thoracolumbar spine radiographs and DXA spine scans (≤6months between both exams). Disc degeneration was assessed using the Lane score. The images of 20 randomly selected individuals were assessed by two readers. Almost 13% of the thoracic levels were not assessable on the DXA scans. For the identification of the intervertebral levels on the DXA scans as interpretable or not, the intra-reader agreement was good (κ=0.81) and the inter-reader agreement was fair (κ=0.27-0.36). For the diagnostic criteria (osteophytes, disc space narrowing, osteosclerosis, overall grade), the intra-reader agreement was excellent for the radiographs (κ=0.89-0.92), good for the DXA scans (κ=0.64-0.83) and fair to moderate for the between-method comparison (κ=0.25-0.44). The inter-reader agreement was moderate to good for the radiographs (κ=0.49-0.66) and fair to good for the DXA scans (κ=0.32-0.74). In the per patient analysis (the most severe grade), the intra-reader agreement was excellent for the radiographs (κ=0.85-0.94), moderate to excellent for the DXA scans (κ=0.53-0.85) and poor to good for the between-methods comparison (κ=0.17-0.63). Our results do not support the use of DXA scans for the assessment of thoracolumbar disc degeneration.

Contributions of Clinical and Technical Factors to Longitudinal Change in Trabecular Bone Score and Bone Density: A Registry-Based Individual-Level Analysis.

Lumbar spine trabecular bone score (TBS), a gray-level texture measure derived from spine dual-energy X-ray absorptiometry (DXA) images, is a bone mineral density (BMD)-independent risk factor for fracture. An unresolved question is whether TBS is sufficiently responsive to change over time or in response to widely used osteoporosis therapy at the individual level to serve as a useful biomarker. Using the Manitoba DXA Registry, we identified 11,643 individuals age 40 years and older with two fan-beam DXA scans performed on the same instrument within 5 years (mean interval 3.2 years), of whom 6985 (60.0%) received antiresorptive osteoporosis medication (majority oral bisphosphonate) between the scans. We examined factors that were associated with a change in lumbar spine TBS, lumbar spine BMD, and total hip BMD exceeding the 95% least significant change (LSC). Change exceeding the LSC was identified in 23.0% (9.3% increase, 13.8% decrease) of lumbar spine TBS, 38.2% (22.1% increase, 16.1% decrease) lumbar spine BMD, and 42.5% (17.6% increase, 24.9% decrease) total hip BMD measurement pairs. From regression models, the variables most strongly associated with significant change in TBS (decreasing order) were tissue thickness change, acquisition mode change, weight change, and spine percent fat change. Consistent with the insensitivity of TBS to oral antiresorptive therapies, use of these agents showed very little effect on TBS change. In contrast, for both spine BMD change and total hip BMD change, osteoporosis medication use was the most significant variable, whereas tissue thickness change, acquisition mode change, and weight change had relatively weak effects. In summary, change in spine TBS using the present algorithm appears to be strongly affected by technical factors. This suggests a limited role, if any, for using TBS change in untreated individuals or for monitoring response to antiresorptive treatment in routine clinical practice with the current version of the TBS algorithm. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Trabecular Bone Score Reference Values for Children and Adolescents According to Age, Sex, and Ancestry.

Trabecular bone score (TBS) is used for fracture prediction in adults, but its utility in children is limited by absence of appropriate reference values. We aimed to develop reference ranges for TBS by age, sex, and population ancestry for youth ages 5 to 20 years. We also investigated the association between height, body mass index (BMI), and TBS, agreement between TBS and lumbar spine areal bone mineral density (aBMD) and bone mineral apparent density (BMAD) Z-scores, tracking of TBS Z-scores over time, and precision of TBS measurements. We performed secondary analysis of spine dual-energy X-ray absorptiometry (DXA) scans from the Bone Mineral Density in Childhood Study (BMDCS), a mixed longitudinal cohort of healthy children (n= 2014) evaluated at five US centers. TBS was derived using a dedicated TBS algorithm accounting for tissue thickness rather than BMI. TBS increased only during ages corresponding to pubertal development with an earlier increase in females than males. There were no differences in TBS between African Americans and non-African Americans. We provide sex-specific TBS reference ranges and LMS values for calculation of TBS Z-scores by age and means and SD for calculation of Z-scores by pubertal stage. TBS Z-scores were positively associated with height Z-scores at some ages. TBS Z-scores explained only 27% and 17% of the variance of spine aBMD and BMAD Z-scores. Tracking of TBS Z-scores over 6 years was lower (r= 0.47) than for aBMD or BMAD Z-scores (r= 0.74 to 0.79), and precision error of TBS (2.87%) was greater than for aBMD (0.85%) and BMAD (1.22%). In sum, TBS Z-scores provide information distinct from spine aBMD and BMAD Z-scores. Our robust reference ranges for TBS in a well-characterized pediatric cohort and precision error estimates provide essential tools for clinical assessment using TBS and determination of its value in predicting bone fragility in childhood and adolescence. © 2022 American Society for Bone and Mineral Research (ASBMR).

Trabecular Bone Score (TBS) Varies with Correction for Tissue Thickness Versus Body Mass Index: Implications When Using Pediatric Reference Norms.

Trabecular bone score (TBS) derived from secondary analysis of lumbar spine dual-energy X-ray absorptiometry (DXA) scans improves fracture prediction independent of bone mineral density (BMD) in adults. The utility of TBS to assess fracture risk in younger patients has not been established because pediatric norms have been lacking. Robust TBS reference data from the Bone Mineral Density in Childhood Study (BMDCS) have been published. TBS values for the BMDCS study were derived using an algorithm that accounts for tissue thickness (TBSTH ) rather than the commercially available algorithm that adjusts for body mass index (BMI; TBSBMI ). We examined the magnitude of differences in TBSTH and TBSBMI in a cohort of 189 healthy youth. TBS values using both algorithms increased with age and pubertal development in a similar pattern. However, TBSBMI values were systematically and significantly higher than TBSTH (mean=0.06, p< 0.0001). The difference between calculated TBSBMI and TBSTH was not uniform. Differences were greater at lower TBS values, in males, in older individuals, in those at later Tanner stages, and in those with a greater BMI Z-score. These systematic differences preclude the development of a simple formula to allow conversion of TBSBMI to TBSTH "equivalents." Because of these systematic differences in these two algorithms, using an individual's TBSBMI to calculate a Z-score using the BMDCS TBSTH reference values results in a falsely higher TBS Z-score (differences mean=0.73, interquartile range [IQR]=0.3 to 1.6). Until TBSTH software for Hologic DXA equipment becomes commercially available, BMDCS TBS reference norms should not be used. © 2023 American Society for Bone and Mineral Research (ASBMR).

What Role Does Trabecular Bone Score Play in Chronic Inflammatory Rheumatic Diseases?

Patients suffering from rheumatic inflammatory diseases, e.g., systemic sclerosis, rheumatoid arthritis, and ankylosing spondylitis, are at risk of low bone mass. Dual-energy X-ray Absorptiometry (DXA) is the traditional radiological measurement technique for bone mineral density (BMD). The recently developed trabecular bone score (TBS) enhances the skeletal information provided by standard BMD. It re-analyzes the spatial dynamics of pixel intensity changes in lumbar spine DXA images, defining a quantitative index, characterizing trabecular bone microarchitecture. It has been demonstrated that low TBS values are associated with an increased incidence of fractures in patients with rheumatic diseases. These methods used together for bone damage evaluation can be of value to identify individuals who will potentially fracture. The main scientific literature on the clinical aspects of osteoporosis, including the use of TBS in evaluating this pathology, are herein reported aimed at shedding light on the role trabecular bone score plays in chronic inflammatory rheumatic diseases.

Modestly degraded microarchitecture and high serum levels of osteopontin in Swedish females with anorexia nervosa

PurposeAdult women with long-time anorexia nervosa (AN) are believed to have osteopenia (T-score ≤ 1.0) in 93 % and osteoporosis (T-score ≤ 2.5) in 38 %. Bone microarchitecture assessed by Trabecular Bone Score (TBS) predicts osteoporotic fractures. Our aim was to evaluate the microarchitecture in adult females with AN by determining TBS and to identify factors potentially associated with TBS, such as bone turnover markers.Methods20 female patients with AN (DSM IV), aged 27.8 ± 4.4 years, BMI 16.6 ± 0.6 kg/m2 and duration of illness of 8.5 ± 5 years had previously been evaluated with dual-energy X-ray absorptiometry (DXA). TBS measurements were now obtained, using iNsight software, from spinal DXA images. Serum levels of bone turnover markers were determined in patients and healthy normal-weight controls.ResultsCompared to controls serum values of osteopontin were higher (p = 0.009). BMD in patients with AN was reduced by at least 1.0 SD at one or more skeletal sites in 65 % of patients and by at least 2.5 SD in 20 %. Only one of the patients (5%) had suffered a fracture. TBS (mean 1.35 ± 0.06; median 1.36 (1.23–1.44) was in the lower normal range (≥ 1.35). 40 % of patients showed partially (> 1.20 and < 1.35) but none showed a fully degraded micro-architecture.ConclusionsIn Swedish AN patients we found a low reduction of BMD and fracture history. The bone microarchitecture, evaluated for the first time for this group by TBS, was only modestly compromised, and to a lesser extent than expected for this group of patients with AN.Level of evidenceLevel V; cross-sectional descriptive study.

Trabecular Bone Score and Bone Quality in Systemic Lupus Erythematosus Patients

Background: Systemic lupus erythematosus (SLE) patients run a higher risk of having low bone mass due to multifactorial events that include physical inactivity, persistent inflammation, low vitamin D levels, and glucocorticoid treatment. This study aimed at obtaining a comparison between bone involvement in SLE patients and healthy matched subjects (HS).Methods: A total of 40 SLE females (average age 54.1 ± 16.3 years) and 40 age–gender matched HS (average age 54.2 ± 15.9 years) were enrolled after having obtained informed written consent. Bone mineral density (BMD, g/cm2) of the lumbar spine (L1–L4) was analyzed by a dual-energy X-ray absorptiometry (DXA) scan (GE, Lunar Prodigy). The lumbar spine trabecular bone score (TBS) was derived for each spine DXA examination by the TBS index (TBS iNsight Medimaps).Results: The lumbar spine TBS score was statistically significantly lower in SLE patients than in HS (0.797 ± 0.825 vs. 1.398 ± 0.207, p < 0.001, as was BMD (p < 0.001) in all areas examined.Conclusions: SLE is associated with significant low bone mass as evidenced by DXA and TBS. This study emphasizes the importance of using DXA and TBS in the evaluation of the different aspects of bone architecture.

Prediction of osteoporotic fragility re-fracture with lumbar spine DXA-based derived bone strain index: a multicenter validation study.

Dual-energy X-ray absorptiometry (DXA) can provide quantitative (bone mineral density, BMD) and qualitative (trabecular bone score, TBS) indexes of bone status, able to predict fragility fractures in most osteoporotic patients. A new qualitative index of bone strength, based on finite element analysis and named bone strain index (BSI), has been recently developed from lumbar DXA scan. This study presents the validation results of BSI prediction for re-fracture in osteoporotic patients with fragility fractures. In three academic hospitals, 234 consecutive fractured patients with primary osteoporosis (209 females) performed a spine X-ray for the calculation of spine deformity index (SDI) and DXA densitometry for BMD, TBS and BSI at the basal time and in the follow-up at each clinical check. A subsequent fracture was considered as one unity increase of SDI. For each unit increase of the investigated indexes, the univariate hazard ratio of re-fracture, 95% CI, p value and proportionality test p value are for age 1.040, 1.017-1.064, 0.0007 and 0.2529, respectively, and for BSI 1.372, 1.038-1.813, 0.0261 and 0.5179, respectively. BSI remained in the final multivariate model as a statistically significant independent predictor of a subsequent re-fracture (1.332, 1.013-1.752 and 0.0399) together with age (1.039, 1.016-1.064 and 0.0009); for this multivariate model proportionality test, p value is 0.4604. BSI appears to be a valid DXA index of prediction of re-fracture, and it can be used for a more refined risk assessment of osteoporotic patients.

Prevalence and Predictors of Compromised Bone Mineral Density in Pediatric Eosinophilic Esophagitis.

The aim of the study was to determine whether patients with eosinophilic esophagitis (EoE) have lower bone mineral density (BMD) than expected and if bone deficits are more pronounced in subgroups of patients according to comorbidities (atopic disease and joint hypermobility) or treatments (dietary restriction, medication exposure). Retrospective chart review was performed to obtain clinical data, including length of diagnosis, comorbidities, and methods of treatment for patients with EoE ages 3 to 21 years who had a lumbar spine dual-energy x-ray absorptiometry scan performed between 2014 and 2017. BMD was standardized by calculation of age, sex, and race-specific z scores. A total of 269 patients met study criteria. The mean BMD z score (-0.55, 95% confidence interval: -0.68, -0.42) was lower than expected (P < 0.0001), and the prevalence of low BMD z score (≤-2.0) was higher than expected (8.5%, 95% confidence interval: 5.2%-11.9%, P < 0.0001). In multivariable regression models, BMD z scores were -0.27 lower among those following an elimination diet and -0.65 lower among those with any lifetime use of a proton pump inhibitor (93% of the sample). There was no association with swallowed steroid use. In our sample, pediatric patients with EoE had a slightly lower BMD z score compared to peers, and the prevalence of low BMD was higher than expected. Taken cautiously given the limitations of our sample, risk factors for bone deficits included any lifetime use of proton pump inhibitor and a restrictive elimination diet, but not swallowed steroid use. Larger prospective studies are needed to better characterize risk factors for low BMD to help inform screening, selection of therapies, and provide appropriate anticipatory guidance for patients with EoE.

Trabecular Bone Score And Bone Mineral Density In Older Adults

The Trabecular Bone Score (TBS) is an estimate of the healthiness of bone microarchitecture that is based on the mathematical reconstruction of 3D micro-computed tomography (μCT) scans using 2D Dual-energy X-ray Absorptiometry (DXA). Compared to bone mineral density (BMD), TBS is a relatively new DXA-derived metric for predicting fracture risk. PURPOSE: This study examined the associations between classically measured vertebral bone mineral density (BMD) and TBS in inactive older adults. METHODS: For the present analyses, we included pre-training data from 19 older adults (X±SD; 71±4.2y, 4 black, 6 males) participating in an ongoing exercise intervention (REALPA). Whole-body and lumbar spine scans were acquired using a Hologic Horizon®A DXA scanner to determine BMD. TBS iNsight™ was used to determine the TBS score from lumbar spine DXA scans. Multivariate analyses were used to determine associations between whole-body and lumbar spine BMD with TBS scores, and sex differences were assessed by t-tests. RESULTS: A strong correlation between both whole-body BMD and lumbar spine TBS (r=0.815, p<0.0001) was observed; this was also true for lumbar spine BMD and lumbar spine TBS (r=0.834, p<0.0001). Sex differences were found (males vs. females) for Whole-body BMD (g/cm2; 1.156±0.12 vs 0.972±0.10, p<0.009), lumbar spine BMD (1.150±0.20 vs 0.920±0.15, p<0.05), and lumbar spine TBS (1.409±0.10 vs 1.285±.09, p<0.05). CONCLUSION: The sex differences for BMD and TBS are consistent with the literature, with males having higher BMD and TBS. Strong correlations between BMD and TBS suggest that TBS bone has construct validity. However, future studies are still warranted to determine whether TBS scoring provides clinically meaningful insight into fracture risk beyond traditional BMD. Furthermore, future research studies are warranted to determine whether exercise induced changes TBS are sensitive markers for exercise induced bone remodeling, which would provide additional insight into the clinical utility of TBS. This study was supported by the NIH 5R21AG058181-02.

Bone densities and bone geometry in children and adolescents with arthrogryposis.

To describe bone densitometry results using lumbar spine dual-energy X-ray absorptiometry and forearm peripheral quantitative computed tomography (pQCT) in children with arthrogryposis multiplex congenita (AMC). Prospective study. Lumbar spine areal bone mineral density (BMD) was measured in 58 participants (mean age 6.8years, range 1month to 19.7years; 26 males). The diagnostic subgroup was Amyoplasia in 27 participants, distal arthrogryposis (unclassified, n=13; type 2A, n=1; type 2B, n=2; type 8, n=2) in 18 patients, an unclassified form of arthrogryposis in 6 patients, and a syndromic form of arthrogryposis in 7 patients. The mean lumbar spine areal BMD was -0.4 (SD: 1.5) which was significantly below 0 (p<0.05, one-sample t-test). The mean lumbar spine bone mineral apparent density z-score (+0.4 [SD: 1.4]), a measure that is largely independent of bone size, was not significantly different from 0 (P>0.05). A subset of 22 patients aged 6years or older (mean age 10.9years, 11 males) had forearm pQCT analysis. Mean z-scores for trabecular and cortical volumetric BMD at the radius were similar to healthy controls. Radius periosteal bone circumference and bone mineral content were appropriate for height. These densitometric results did not differ between patients with Amyoplasia or individuals with other diagnoses. Low areal BMD in children and adolescents with AMC reflects their smaller bone size rather than a specific bone mass deficit. These data do not suggest that children and adolescents with AMC in general require regular monitoring by bone densitometry unless there are specific clinical concerns.

A Newly Recognized DXA Confounder: The Potassium-Binding Medication Sodium Zirconium Cyclosilicate

Objective: Radio-dense artifacts, including contrast material, alter dual-energy X-ray absorptiometry (DXA) results. An apparent diffuse artifact was identified during spine DXA acquisition in a patient without recent radiographic procedures. The patient reported taking sodium zirconium cyclosilicate (SZC; Lokelma®) 10 g 1 h before scanning. SZC is a potassium-binding agent recently marketed to treat hyperkalemia. Given the chemical composition, we hypothesized that SZC may alter DXA results. This study evaluated if SZC affects DXA results using an encapsulated spine and a total body phantom. Methodology: An encapsulated spine and total body phantom were scanned using a Lunar iDXA. Each phantom was scanned 5 times serially without repositioning in 5 configurations: (1) Bare, (2) 45 mL tap water, (3) 90 mL water, (4) 10 g SZC in 45 mL of water, and (5) 30 g SZC in 90 mL of water. Water and SZC was contained in plastic quart bags, folded, and placed over L2-3 on the spine phantom and flat over the pelvis/torso of the total body phantom. Results: Tap water did not change spine phantom measurements, but did increase (p < 0.05) total body phantom lean mass 46 g and 89 g with 45 mL and 90 mL, respectively. SZC 10 g or 30 g increased (p < 0.001) L2 and L3 bone mineral density (BMD) 18%–110%, mean 0.295 and 0.924 g/cm2, respectively, while L1 and L4 BMD was statistically, but not clinically, altered by <0.010 g/cm2. A dose-dependent change (p < 0.001) in total body phantom trunk measurements was demonstrated. The 10 g dose increased lean mass 16.8% and BMC 1%; fat mass was reduced 16.6%, while 30 g increased lean 41.9%, BMC 3.2%, and decreased fat 42.9%. Conclusion: SZC confounds BMD and body composition phantom measurements. It is likely that SZC alters DXA results in humans. DXA technologists and interpreters should be aware of this confounder.

Do patients that fracture with normal DXA-measured BMD have normal bone?

Dual-energy X-ray absorptiometry (DXA) measured bone mineral density (BMD) at the hip and spine is widely used to diagnose osteoporosis. However, patients that sustain "osteoporosis-related" fractures often have normal BMD at these sites. The aim of this study was to explore whether older adults with fracture, but normal reported hip and spine BMD, also have normal bone using additional clinically available assessments. This retrospective electronic medical record study included 387 patients evaluated by a university-based fracture liaison service with spine and hip DXA; 32 (8.3%) had normal spine/hip BMD reported. In this cohort, clinically available bone data including 0.3 and ultradistal radius T-scores, trochanteric T-scores, lumbar spine trabecular bone score (TBS), L1 opportunistic CT Hounsfield units (HU), and femoral cortical index (FCI) were assessed. One or more of the above noted studies were available in 30/32 patients. UD and 0.3 radius results were available in 21 patients, and 18 (85.7%) had T-scores < - 1.0. Trochanteric values were available in 16; T-scores were < - 1.0 in 18.8%. TBS data were available in 24; partially degraded or degraded values were present in 41.7%. L1 opportunistic CT was available in 25 patients, 80% were below normal, and < 150 HU. Finally, femoral cortical index (FCI) was measurable in 9 subjects; 66.7% were below < 0.4. When including all additional available data in the skeletal assessment, only 5/387 (1.3%) were identified with normal bone. Patients with normal spine/hip BMD who sustain fracture rarely have normal bone when all available data are considered.

Use of trabecular bone score for risk stratification of patients with monoclonal gammopathy of undetermined significance

Monoclonal gammopathy of undetermined significance (MGUS) is a common finding in clinical practice. The risk for developing MGUS increases with aging in parallel with age-associated increases in fracture risk. Although there is good evidence that patients with MGUS suffer from increased fracture risk, no standardized guidelines exist for the evaluation and/or management of skeletal health in patients with MGUS. Trabecular bone score (TBS), a texture index derived from lumbar spine (LS) dual-energy x-ray absorptiometry (DXA) images, provides information about trabecular microarchitecture independent of bone mineral density (BMD). We retrospectively identified 155 adult patients diagnosed with MGUS between 2005 and 2018. This group was matched 1:1 to a control group for sex, age and BMI. TBS was performed retrospectively, and values categorized as low (≤1.23), intermediate (1.23-1.31) or normal (>1.31). Patients had a mean±SD age of 69.6±10.0. BMD was performed within a median of 28months (IQR 1-78) of MGUS diagnosis. Cases had a non-statistically significant higher rate of fractures compared to control subjects (27 vs. 17, respectively, p=0.1). Patients with MGUS had a significantly lower TBS (1.31±0.13 vs. 1.34±0.12, respectively, p<0.05) and lower LS BMD (1.215±0.223 vs. 1.275±0.247, p<0.05) compared to controls. Although fractures occurred more commonly in those control subjects with significantly lower TBS values, this was not the case in subjects with MGUS (TBS 1.299 vs. 1.313 in cases with vs. without fractures p=0.313). Similarly, there was no difference in T-scores in cases with or without fractures (-1.33 vs. -1.37, respectively, p=0.56). Despite patients with MGUS having a significantly increased fracture risk compared to age-, sex- and BMI-matched control subjects, neither assessment of BMD nor TBS, obtained within two years of MGUS diagnosis, were able to accurately risk stratify MGUS patients. Unlike control subjects, patients with MGUS tend to fracture despite normal BMD and intermediate or normal TBS values, suggesting that deterioration of cortical rather than trabecular skeletal components may be more important for the increased fracture risk seen in MGUS.

Prevalence of Osteoporosis in Patients Undergoing Lumbar Fusion for Lumbar Degenerative Diseases: A Combination of DXA and Hounsfield Units.

Retrospective analysis. To investigate the prevalence of osteoporosis (OP) in patients undergoing lumbar fusion for lumbar degenerative diseases (LDD). OP is related to many complications after lumbar fusion for patients with LDD. There are sparse data on the prevalence of OP among this specific population. Moreover, LDD can falsely elevate the bone mineral density measured by dual energy x-ray absorptiometry (DXA), leading to unreliable diagnostic results. Computed tomography (CT) Hounsfield unit (HU) values can help identify osteoporotic patients undetected by DXA. A total of 479 patients aged≥50 years undergoing lumbar fusion for LDD were reviewed. The diagnosis of OP using DXA was based on World Health Organization criterion. The criterion for OP diagnosed on CT scan was the L1-HU value≤110. The prevalence of OP diagnosed on lumbar DXA, hip DXA, and both was 32.4%, 19.6%, 39.7%, respectively. The females had higher prevalence of OP diagnosed on DXA (spine and hip) than males (48.9% vs. 27.1%, P < 0.001). In females but not males, the prevalence of OP significantly increased with age (females, 50-59: 28.0%, 60-69: 58.1%, ≥70: 78.8%, P < 0.001). Patients having primary diagnosis of degenerative lumbar scoliosis had the higher prevalence of OP than the rest patients (56.5% vs. 36.8%, P = 0.002). Among the 324 patients diagnosed with non-OP by lumbar DXA, the prevalence of OP diagnosed on CT scan was 25.9%, it increased with age and was also highest in patients with degenerative lumbar scoliosis. OP was quite common among patients aged≥50 years undergoing lumbar fusion for LDD, especially for females aged≥60 years or patients having degenerative lumbar scoliosis. Older patients or patients having degenerative lumbar scoliosis are more likely to have unreliable lumbar T-scores. Measurements of HU values can help identify more osteoporotic patients in this population. 3.

Trabecular bone scores in young HIV-infected men: a matched case-control study

BackgroundScreening for osteoporosis with dual-energy X-ray absorptiometry (DXA) is recommended for male HIV-infected patients only above the age of 50. Recently, trabecular bone score (TBS) has been introduced as a novel tool to assess bone microarchitecture using DXA of the lumbar spine. Few studies have reported TBS values in HIV-infected individuals younger than 50 years of age. This study compared TBS values in young males infected with HIV and matched controls, and investigated the associations between TBS and demographic parameters, clinical parameters, and bone mineral density (BMD) scores.MethodsA cross-sectional study of BMD and TBS in HIV-infected men (n = 80) aged between 18 and 50 years and age- and sex-matched controls (n = 80) was conducted.ResultsThe proportion of patients with low BMD (Z-score ≤ − 2) was significantly greater among HIV-infected patients than among matched controls (21.3% [17/80] vs. 8.8% [7/80], p = 0.027). Mean TBS values were significantly lower in HIV-infected patients than in controls (1.41 ± 0.07 vs. 1.45 ± 0.07, p = 0.008). In both groups, TBS values were positively correlated with BMD at the lumbar spine, femoral neck, and total hip (p < 0.001); however, TBS was not correlated with body mass index. In the HIV group, TBS was negatively correlated with the duration of tenofovir disoproxil fumarate(TDF) exposure (p = 0.04).ConclusionYoung men infected with HIV had abnormal bone trabecular microarchitecture, as assessed by both TBS and BMD. TBS values were correlated with both BMD and the duration of TDF exposure.

Combining Frailty and Trabecular Bone Score Did Not Improve Predictive Accuracy in Risk of Major Osteoporotic Fractures

It is recognized that the trabecular bone score (TBS) provides skeletal information, and frailty measurement is significantly associated with increased risks of adverse health outcomes. Given the suboptimal predictive power in fracture risk assessment tools, we aimed to evaluate the combination of frailty and TBS regarding predictive accuracy for risk of major osteoporotic fracture (MOF). Data from the prospective longitudinal study of CaMos (Canadian Multicentre Osteoporosis Study) were used for this study. TBS values were estimated using lumbar spine (L1 to L4 ) dual-energy X-ray absorptiometry (DXA) images; frailty was evaluated by a frailty index (FI) of deficit accumulation. Outcome was time to first incident MOF during the follow-up. We used the Harrell's C-index to compare the model predictive accuracy. The Akaike information criterion, likelihood ratio test, and net reclassification improvement (NRI) were used to compare model performances between the model combining frailty and TBS (subsequently called "FI + TBS"), FI-alone, and TBS-alone models. We included 2730 participants (mean age 69 years; 70% women) for analyses (mean follow-up 7.5 years). There were 243 (8.90%) MOFs observed during follow-up. Participants with MOF had significantly higher FI (0.24 versus 0.20) and lower TBS (1.231 versus 1.285) than those without MOF. FI and TBS were significantly related with MOF risk in the model adjusted for FRAX with bone mineral density (BMD) and other covariates: hazard ratio (HR) = 1.26 (95% confidence interval [CI] 1.11-1.43) for per-SD increase in FI; HR = 1.38 (95% CI 1.21-1.59) for per-SD decrease in TBS; and these associations showed negligible attenuation (HR = 1.24 for per-SD increase in FI, and 1.35 for per-SD decrease in TBS) when combined in the same model. Although the model FI + TBS was a better fit to the data than FI-alone and TBS-alone, only minimal and nonsignificant enhancement of discrimination and NRI were observed in FI + TBS. To conclude, frailty and TBS are significantly and independently related to MOF risk. Larger studies are warranted to determine whether combining frailty and TBS can yield improved predictive accuracy for MOF risk. © 2020 American Society for Bone and Mineral Research.

Diagnostic performance of morphometric vertebral fracture analysis (MXA) in children using a 33-point software program.

There is significant inter and intraobserver variability in diagnosing vertebral fractures in children. We aimed to evaluate the diagnostic accuracy of morphometric vertebral fracture analysis (MXA) using a 33-point software program designed for adults, on dual-energy x-ray absorptiometry (DXA) images of children. Lateral spine DXA images of 420 children aged between 5 and 18years were retrospectively reviewed. Vertebral fracture assessment (VFA) by an expert pediatric radiologist using Genant's semiquantitative scoring system served as the gold standard. All 420 DXA scans were analyzed by a trained radiographer, using semi-automated software (33-point morphometry). VFA of a random sample of 100 DXA was performed by an experienced pediatric clinical scientist. MXA of a random sample of 30 DXA images were analyzed by three pediatric radiologists and the pediatric clinical scientist. Diagnostic accuracy and inter and intraobserver agreement (kappa statistics) were calculated. Overall sensitivity, specificity, false positive (FP) and false negative (FN) rates for the radiographer using the MXA software were 80%, 90%, 10%, and 20% respectively and for mild fractures alone were 46%, 92%, 8%, and 54% respectively. Overall sensitivity, specificity, FP, and FN rates for the four additional observers using MXA were 89%, 79%, 21%, and 11% respectively and for mild fractures alone were 36%, 86%, 14%, and 64% respectively. Agreement between two expert observers was fair to good for VFA and MXA [kappa=0·29 to 0·76 (95% CI: 0·17-0·88) and 0·29 to 0·69 (95% CI: 0·17-0·83)] respectively. MXA using a 33-point technique developed for adults is not a reliable method for the identification of mild vertebral fractures in children. A pediatric standard is required which not only incorporates specific vertebral body height ratios but also the age-related physiological changes in vertebral shape that occur throughout childhood.

Major and minor discordance in dual-energy X-ray absorptiometry diagnosis of osteoporosis – A cross-sectional, population-based, observational study in Indian women

Objective:The study objective was to evaluate the presence of major and minor discordance in the diagnosis of osteoporosis in a population-based screening program of Indian women using hip and spine dual-energy X-ray absorptiometry (DEXA).Methods:In this institutional review board-approved study, a population-based screening program was offered to women aged > 40 using a mobile van model. A total of 5708 women underwent DEXA between May 2012 and May 2016 as a population-based, opt-in screening program offered to women as an outreach program. Bone mineral density (BMD) was measured at the hip and spine, which was used to derive T-scores and to determine the prevalence of discordance.Results:The densitometry scores were concordant in 42.50% of the cases, with abnormal bone mineral density, whereas in 54.15% of cases, there was minor discordance and major discordance in 3.35% of cases. Body mass index, weight, age, and postmenopausal status of the patient were important predictors of the presence of discordance.Conclusions:Clinicians and epidemiologists should be prepared for at least five out of every ten women screened to have discordance of the T scores at the two anatomical sites scanned. If there is discordance of BMD in underweight persons or in those with low body mass index, then causes other than physiological discordance should be considered, which may be further evaluated.