Dual-energy X-ray Absorptiometry Analysis Research Articles

Quality assessment in bone densitometry: a case of incorrect hip analysis

Abstract Dual-energy X-ray absorptiometry (DXA) is a sophisticated imaging technique utilized in the field of medical diagnostics to measure bone mineral density. The significance of DXA lies in its ability to accurately assess bone health, which is crucial in the evaluation of osteoporosis, a condition characterized by weakened bones and heightened susceptibility to fractures. Despite its widespread adoption and clinical utility, DXA is not without limitations. Factors such as body size, tissue hydration, the presence of metal implants, improper equipment installation and maintenance, as well as inadequate education and training in bone densitometry may influence DXA measurements, necessitating careful interpretation by trained professionals. We present a case to show the errors that occurred during DXA analysis leading to dramatic T-score changes, highlighting the importance of technologists’ adherence to manufacturers’ recommendations, to ensure the accurate processing of DXA scans and diagnosis.

Evaluation of bone density and microarchitecture in adult patients with X-linked hypophosphatemic rickets: A pilot longitudinal study

X-linked Hypophosphatemia (XLH) is the most common type of inherited rickets. Although the clinical features are well characterized, bone structure, mineralization, and biomechanical properties are poorly known. Our aim was to analyze bone properties in the appendicular and axial skeleton of adults with XLH. In this observational case-control study, each affected patient (N = 14; 9 females; age 50 ± 15 years) was matched by sex, age and body mass index to a minimum of two healthy controls (N = 34). Dual-energy X-ray Absorptiometry (DXA) analyses revealed that areal bone mineral density (aBMD) was higher in XLH patients at the lumbar spine (Z score mean difference = +2.47 SD, P value = 1.4 × 10−3). Trabecular Bone Score was also higher at the lumbar spine (P value = 1.0 × 10−4). High Resolution peripheral Quantitative Computed Tomography (HRpQCT) demonstrated that bone cross-sectional area was larger at the distal radius (P value = 6 × 10−3). Total and trabecular volumetric BMD were lower at both sites. Trabecular bone volume fraction was also lower with fewer trabecular numbers at both sites. However, bone strength evaluated by micro-finite element analyzes revealed unaffected bone stiffness and maximum failure load. Evaluation of bone mineralization with aBMD by DXA at the distal radius correlated with vBMD by HRpQCT measurements at both sites. PTH levels were inversely correlated with trabecular vBMD and BV/TV at the tibia. We then followed a subset of nine patients (median follow-up of 4 years) and reassessed HRpQCT. At the tibia, we observed a greater decrease than expected from an age and sex standardized normal population in total and cortical vBMD as well as a trabecularization of the cortical compartment. In conclusion, in adult patients with XLH, bone mineral density is high at the axial skeleton but low at the appendicular skeleton. With time, microarchitectural alterations worsen. We propose that noninvasive evaluation methods of bone mineralization such as DXA including the radius should be part of the management of XLH patients. Larger studies are needed to evaluate the clinical significance of BMD changes in XLH patients under conventional or targeted therapies.

Evaluation of the Relationship between Osteoporosis and Body Fat Mass of the Upper and Lower Extremities by Dual-Energy X-Ray Absorptiometry

Background: Using dual-energy X-ray absorptiometry, body fat mass has been determined. The assessment of body fat mass was conducted utilizing dual-energy X-ray absorptiometry analysis of the pelvis and vertebral column. While it is acknowledged that osteoporosis can impact both body fat mass and bone mineral density, the particulars of this relationship currently remain uncertain. Objective: The aim of the present investigation is to assess gender differences in the effects of osteoporosis on the body fat mass of the upper and lower extremities. Method: 170 individuals participated (85 males and 85 females) in this study. Patients who presented with bone discomfort consisted of 40 males and 40 females. In addition, 90 apparently healthy volunteers, consisting of 45 males and 45 females, were studied and considered to constitute the control group. Dual-energy X-ray absorptiometry was utilized to determine the bone mineral density and body fat mass of every participant for all body parts. Results: Statistically significant disparities in body fat mass were observed between males and females, as well as between the control group and patients diagnosed with osteoporosis. Conclusions: Our results indicate that the patients with osteoporosis showed an increase in body fat mass (for both sexes). Other results obtained from this research revealed that females were more frequently suffering from osteoporosis than males.

Assessing head muscles measured with MRI as alternative to estimate muscle mass in older persons with dementia

AbstractBackgroundCurrent evidence suggests an association between sarcopenia and multiple negative outcomes. Traditional methods to diagnose sarcopenia are based on dual‐energy X‐ray absorptiometry (DXA) and whole body magnetic resonance imaging. These tests are complicated, time‐consuming and expensive. We aim to bring a more accessible way to diagnose sarcopenia, making its detection easier in a neurological and dementia setting where brain MRI are regularly ordered. Therefore, we aim to compare the traditional methods of muscle mass and function vs. muscle quantification using the tongue and the masseter muscle in a standard brain MRI to diagnose sarcopenia in clinical settings.MethodThe H70 study, is a longitudinal study of people born in the Gothenburg area of Sweden aged 70 at baseline. We included 791 participants with available clinical data and MRI. DXA and bioimpedance analyses were used as reference measures. Images were analyzed using 3Dslicer.(figure 1) Adjusted speermarRo coefficients were calculated to assess the correlation between the gold standard (DXA) and the muscle mass of the tongue and masseters.ResultThere was a higher prevalence of women (55,7%). When comparing the different tests to assess muscle mass, we found significant and positive coefficient between both tongue and masseter. Total lean tissue mass (DXA) & Tongue volume (Cm3) Rho = 0,375, total lean tissue mass (DXA) & Total masseter volume (Cm3) Rho = 0,326. < 0.001. (table1,2 Figure 2.)ConclusionThere is a significant positive correlation between total lean tissue mass using DXA and muscle mass calculated with MRI measuring tongue and masseter. Clinical longitudinal Implications of these measurements will be tested in further steps of this research and exposed at the conference.

Assessing bone mineral density in non-weight bearing regions of the body: a texture analysis approach using abdomen and pelvis computed tomography Hounsfield units-a cross-sectional study.

Highlighting a gap in comprehending bone microarchitecture's intricacies using dual-energy X-ray absorptiometry (DXA), this study aims to bridge this chasm by analyzing texture in non-weight bearing regions on axial computed tomography (CT) scans. Our goal is to enrich osteoporosis patient management by enhancing bone quality and microarchitecture insights. Conducted at Busan Medical Center from March 1, 2013, to August 30, 2022, 1,320 cases (782 patients) were screened. After applying exclusion criteria, 458 samples (296 patients) underwent bone mineral density (BMD) assessment with both CT and DXA. Regions of interest (ROIs) included spine pedicle's maximum trabecular area, sacrum Zone 1, superior/inferior pubic ramus, and femur's greater/lesser trochanters. Texture features (n=45) were extracted from ROIs using gray-level co-occurrence matrices. A regression model predicted BMD, spotlighting the top five influential texture features. Correlation coefficients ranged from 0.709 (lowest for total femur BMD) to 0.804 (highest for femur intertrochanter BMD). Mean squared error (MSE) values were also provided for lumbar and femur BMD/bone mineral content (BMC) metrics. The most influential texture features included contrast_32, correlation_32_v, and three other metrics. By melding traditional DXA and CT texture analysis, our approach presents a comprehensive bone health perspective, potentially revolutionizing osteoporosis diagnostics.

A nude mutant rat derived from Sprague Dawley-National Institute of Nutrition rat colony with normal thymus: A potential model for noncommunicable diseases.

A spontaneous mutant rat with a hairless phenotype and an intact thymus was discovered in a long-standing Sprague Dawley-National Institute of Nutrition (SD/NIN) rat colony at a national animal resource facility. We conducted extensive phenotypic and biochemical analyses on this mutant strain to determine its suitability as a preclinical model for immunocompetent testing in noncommunicable disease research. We subjected the mutant rats to strict and frequent phenotypic and genetic surveillance to accomplish this objective. The animals were assessed for food intake, body weight, blood cell profile, clinical chemistry, adipose tissue deposition, and bone mineral density (BMD) using total electrical body conductance (TOBEC) and dual-energy X-ray absorptiometry (DXA) analysis. Initially, only two hairless mutant rats, a male and a female, were born from a single dam in the SD/NIN rat strain. However, the results indicate that the mutant colony propagated from these unique pups displayed distinct phenotypic features and exhibited differences in feeding behavior, weight gain, and clinical biochemistry. The food conversion rate was significantly higher in nude females (2.8-fold) while 26% lower in nude males. Both sexes of nude rats had significantly higher triglycerides and lower glucose levels in females. However, glucose levels did not change in male nude rats. Furthermore, nude female and male rats had significantly lower fat (TOBEC) and bone mineral content (DXA). Nonetheless, BMD was only slightly lower (7%-8%) compared to the heterozygous groups. These findings indicate that the spontaneous mutant rat has the potential to serve as an immunopotent and modulatory testing system in pharmacokinetics/pharmacodynamics and toxicology, which can be further explored for therapeutic drug discovery.

Alteration of Volumetric Bone Mineral Density Parameters in Men with Spinal Cord Injury.

Spinal cord injury (SCI) induces severe losses of trabecular and cortical volumetric bone mineral density (vBMD), which cannot be discriminated with conventional dual-energy X-ray absorptiometry (DXA) analysis. The objectives were to: (i) determine the effects of SCI on areal BMD (aBMD) and vBMD determined by advanced 3D-DXA-based methods at various femoral regions and (ii) model the profiles of 3D-DXA-derived parameters with the time since injury. Eighty adult males with SCI and 25 age-matched able-bodied (AB) controls were enrolled in this study. Trabecular and cortical vBMD, cortical thickness and derived strength parameters were assessed by 3D-SHAPER® software at various femoral subregions. Individuals with SCI had significantly lower integral vBMD, trabecular vBMD, cortical vBMD, cortical thickness and derived bone strength parameters (p < 0.001 for all) in total proximal femur compared with AB controls. These alterations were approximately to the same degree for all three femoral subregions, and the difference between the two groups tended to be greater for cortical vBMD than trabecular vBMD. There were minor differences according to the lesion level (paraplegics vs tetraplegics) for all 3D-DXA-derived parameters. For total proximal femur, the decreasing bone parameters tended to reach a new steady state after 5.1years for integral vBMD, 7.4years for trabecular vBMD and 9.2years for cortical vBMD following SCI. At proximal femur, lower vBMD (integral, cortical and trabecular) and cortical thickness resulted in low estimated bone strength in individuals with SCI. It remains to be demonstrated whether these new parameters are more closely associated with fragility fracture than aBMD.

Detecting whether L1 or other lumbar levels would be excluded from DXA bone mineral density analysis during opportunistic CT screening for osteoporosis using machine learning.

One or more vertebrae are sometimes excluded from dual-energy X-ray absorptiometry (DXA) analysis if the bone mineral density (BMD) T-score estimates are not consistent with the other lumbar vertebrae BMD T-score estimates. The goal of this study was to build a machine learning framework to identify which vertebrae would be excluded from DXA analysis based on the computed tomography (CT) attenuation of the vertebrae. Retrospective review of 995 patients (69.0% female) aged 50years or greater with CT scans of the abdomen/pelvis and DXA within 1year of each other. Volumetric semi-automated segmentation of each vertebral body was performed using 3D-Slicer to obtain the CT attenuation of each vertebra. Radiomic features based on the CT attenuation of the lumbar vertebrae were created. The data were randomly split into training/validation (90%) and test datasets (10%). We used two multivariate machine learning models: a support vector machine (SVM) and a neural net (NN) to predict which vertebra(e) were excluded from DXA analysis. L1, L2, L3, and L4 were excluded from DXA in 8.7% (87/995), 9.9% (99/995), 32.3% (321/995), and 42.6% (424/995) patients, respectively. The SVM had a higher area under the curve (AUC = 0.803) than the NN (AUC = 0.589) for predicting whether L1 would be excluded from DXA analysis (P = 0.015) in the test dataset. The SVM was better than the NN for predicting whether L2 (AUC = 0.757 compared to AUC = 0.478), L3 (AUC = 0.699 compared to AUC = 0.555), or L4 (AUC = 0.751 compared to AUC = 0.639) were excluded from DXA analysis. Machine learning algorithms could be used to identify which lumbar vertebrae would be excluded from DXA analysis and should not be used for opportunistic CT screening analysis. The SVM was better than the NN for identifying which lumbar vertebra should not be used for opportunistic CT screening analysis.

Impact of growth trajectory on sexual maturation in layer chickens.

Recent studies showed that apart from photostimulation, metabolic triggers may independently activate sexual maturation and egg production in chickens. However, the origin, mode of action, and specific target(s) of this metabolic control remain unknown. Beyond body weight (BW), we hypothesize that body composition (BC) and associated specific metabolic signals are involved. Thus, this study was conducted to determine the BW and BC thresholds triggering spontaneous sexual maturation in layer pullets under different growth trajectories. Day-old Lohman LSL lite and Lohman brown lite chicks (n = 210 each) raised in brooding cages under ad libitum (AL) feeding until 8weeks of age were randomly allocated into individual cages and assigned to one of 3 experimental growth profiles; AL, breeder's target (T), restricted 20% below target (R), (n = 70 birds/profile/strain). Birds had free access to water throughout the trial. All hens were maintained on 10h of light (10lux) throughout the rest of the study. Blood and tissue samples were collected throughout the study to measure plasma estradiol (E2) concentrations and organ weights, respectively. Furthermore, carcasses were subjected to Dual-energy X-ray absorptiometry (DEXA) analyses. All analyses were completed with SAS using the MIXED procedure. Results show that R treatment slowed (p < 0.001) growth, delayed age at first egg (FE) and egg production (p < 0.001) and resulted in lower BW at FE (p < 0.001), lower ovary weight and number of follicles (p < 0.001) compared to AL in both strains, whereas, the strain significantly impacted body weight (p < 0.0001), ovary weight (p < 0.001), BW at FE (p < 0.001), age at FE (p < 0.001), egg production (p < 0.0001), E2 (p < 0.0001) and body composition (p < 0.05). For DEXA, AL feeding (p < 0.001) increased fat deposition compared to R. Furthermore, there was a positive correlation between plasma E2 and bone mineral content (p < 0.01) and bone mineral density (p < 0.01). In conclusion, feed allocation impacted growth and BC in a strain dependent manner which resulted in differing age at sexual maturation and egg production. Furthermore, a body fat threshold between 10% to 15% appears to be required for the occurrence of spontaneously sexual maturation in laying hens.

Advancing Use of DEXA Scans to Quantitatively and Qualitatively Evaluate Lateral Spinal Curves, for Preliminary Identification of Adolescent Idiopathic Scoliosis

Dual-energy X-ray absorptiometry (DEXA) scan is an emerging screening method for identifying likely adolescent idiopathic scoliosis (AIS). Using DEXA in an unbiased population sample (the Raine Study), we aimed to report the inter-rater reliability and minimal detectable change (MDC95) for scoliosis curve angle measurement, identify likely AIS prevalence, and the concordance between reported AIS diagnosis and DEXA-identified likely AIS. Scoliosis curve angles were measured using the modified Ferguson method on DEXA scans (n = 1238) at age 20 years. For curve angle inter-rater reliability, two examiners measured angles (6–40°) on 41 scans. Likely, AIS was determined with quantitative and qualitative criteria (modified Ferguson angles ≥ 10° and expert review of spinal curves).The inter-rater reliability for scoliosis curve angle measurement was good–excellent (ICC: 0.82; 95% CI: 0.71–0.89; p < 0.001), and MDC95 was 6.2°. The prevalence of likely AIS was 2.1% (26/1238). Diagnosis of AIS was reported despite little or no scoliosis curve (< 3.8°) for 20 participants (1.6%), and diagnosis of AIS was not reported despite scoliosis curve ≥ 10° for 11 participants (0.9%). Results support the use of modified Ferguson method to measure scoliosis curve angles on DEXA. There is potential utility for using a combination of quantitative measurement and qualitative criteria to evaluate DEXA images, to identify likely AIS for reporting prevalence. Without formal school screening, the analysis of DEXA in this population sample suggested that relying on current health professional diagnosis alone could result in 2.5% of this cohort being at risk of false positive diagnosis or delay in necessary management due to non-diagnosis of AIS.

A Cross-Sectional Study of Adiposity by DXA and the Relationship with Endothelial Function and Low-Grade Inflammation

Introduction: To evaluate body composition, especially visceral adipose tissue (VAT), by dual-energy x-ray absorptiometry (DXA) and its relation to endothelial function investigated by venous occlusion plethysmography (VOP) and ultrasensitive C-reactive protein (hsCRP). Methodology: This is a cross sectional study in adults of both sexes divided into group 1 (BMI, 20-24.9, n=30), group 2 (BMI, 25-29.9, n=22), group 3 (BMI, 30-34.9, n=27) and group 4 (BMI, 35-39.9, n=22). VAT was analyzed, among other parameters of adiposity, by DXA Lunar iDXA, and co-related to endothelial function, anthropometric evaluation, cardiometabolic variables and hsCRP. For statistical analysis, tests of comparison between groups and correlation were performed using the software SPSS version 25. Results: Inverse correlation of TFT (total fat mass), % RFM (regional fat mass), FMI (fat mass index) and VAT were identified with increment of arterial blood flow in VOP, except the decrease of the latter, with increase of BMI, adiposity indexes, especially VAT, between groups. hsCRP values showed a direct correlation with progression of adiposity and VAT, between groups. Conclusions: VAT progression, by DXA analysis, was associated with a decline in endothelial function and increase of inflammation, demonstrating potential use in early identification of individuals with cardiovascular risk (CVR).

CT required to perform robotic-assisted total hip arthroplasty can identify previously undiagnosed osteoporosis and guide femoral fixation strategy

Osteoporosis can determine surgical strategy for total hip arthroplasty (THA), and perioperative fracture risk. The aims of this study were to use hip CT to measure femoral bone mineral density (BMD) using CT X-ray absorptiometry (CTXA), determine if systematic evaluation of preoperative femoral BMD with CTXA would improve identification of osteopenia and osteoporosis compared with available preoperative dual-energy X-ray absorptiometry (DXA) analysis, and determine if improved recognition of low BMD would affect the use of cemented stem fixation. Retrospective chart review of a single-surgeon database identified 78 patients with CTXA performed prior to robotic-assisted THA (raTHA) (Group 1). Group 1 was age- and sex-matched to 78 raTHAs that had a preoperative hip CT but did not have CTXA analysis (Group 2). Clinical demographics, femoral fixation method, CTXA, and DXA data were recorded. Demographic data were similar for both groups. Preoperative femoral BMD was available for 100% of Group 1 patients (CTXA) and 43.6% of Group 2 patients (DXA). CTXA analysis for all Group 1 patients preoperatively identified 13 osteopenic and eight osteoporotic patients for whom there were no available preoperative DXA data. Cemented stem fixation was used with higher frequency in Group 1 versus Group 2 (28.2% vs 14.3%, respectively; p = 0.030), and in all cases where osteoporosis was diagnosed, irrespective of technique (DXA or CTXA). Preoperative hip CT scans which are routinely obtained prior to raTHA can determine bone health, and thus guide femoral fixation strategy. Systematic preoperative evaluation with CTXA resulted in increased recognition of osteopenia and osteoporosis, and contributed to increased use of cemented femoral fixation compared with routine clinical care; in this small study, however, it did not impact short-term periprosthetic fracture risk.

Can Adipose Tissue Influence the Evaluation of Thermographic Images in Adolescents?

Infrared thermography (IRT) is a technology easy to use for clinical purposes as a pre-diagnostic tool for many health conditions. However, the analysis process of a thermographic image needs to be meticulous to make an appropriate decision. The adipose tissue is considered a potential influence factor in the skin temperature (Tsk) values obtained by IRT. This study aimed to verify the influence of body fat percentage (%BF) on Tsk measured by IRT in male adolescents. A total of 100 adolescents (16.79 ± 0.97 years old and body mass index of 18.41 ± 2.32 kg/m²) was divided into two groups through the results of a dual-energy X-ray absorptiometry analysis: obese (n = 50, %BF 30.21 ± 3.79) and non-obese (n = 50, %BF 11.33 ± 3.08). Thermograms were obtained by a FLIR T420 infrared camera and analyzed by ThermoHuman® software version 2.12, subdividing the body into seven regions of interest (ROI). The results showed that obese adolescents presented lower mean Tsk values than the non-obese for all ROIs (p < 0.05), with emphasis on the global Tsk (0.91 °C) and anterior (1.28 °C) and posterior trunk (1.18 °C), with "very large" effect size values. A negative correlation was observed in all the ROI (p < 0.01), mainly in the anterior (r = -0.71, p < 0.001) and posterior trunk (r = -0.65, p < 0.001). Tables of thermal normality were proposed for different ROIs according to the classification of obesity. In conclusion, the %BF affects the registered Tsk values in male Brazilian adolescents assessed by IRT.

Noninvasive monitoring of muscle atrophy and bone metabolic disorders using dual-energy X-ray absorptiometry in diabetic mice.

Tracking metabolic changes in skeletal muscle and bone using animal models of diabetes mellitus (DM) provides important insights for the management of DM complications. In this study, we aimed to establish a method for monitoring changes in body composition characteristics, such as fat mass, skeletal muscle mass (lean mass), bone mineral density, and bone mineral content, during DM progression using a dual-energy X-ray absorptiometry (DXA) system in a mouse model of streptozotocin (STZ)-induced type 1 DM. In the DM model, STZ administration resulted in increased blood glucose levels, increased water and food intake, and decreased body weight. Serum insulin levels were significantly decreased on day 30 of STZ administration. The DXA analysis revealed significant and persistent decreases in fat mass, lower limb skeletal muscle mass, and bone mineral content in DM mice. We measured tibialis anterior (TA) muscle weight and performed a quantitative analysis of tibial microstructure by micro-computed tomography imaging in DM mice. The TA muscle weight of DM mice was significantly lower than that of control mice. In addition, the trabecular bone volume fraction, trabecular thickness, trabecular number, and cortical thickness were significantly decreased in DM mice. Pearson's product-moment correlation coefficient analysis showed a high correlation between the DXA-measured and actual body composition. In conclusion, longitudinal measurement of body composition changes using a DXA system may be useful for monitoring abnormalities in muscle and bone metabolism in animal models of metabolic diseases such as DM mice.

Relationship between postural changes, osteoarthritis and bone mineral density in postmenopausal women

Objectives To assess the relationship between postural changes, osteoarthritis (OA) and bone mineral density (BMD) in postmenopausal women. Methods A total of 127 Brazilian women, aged 45 years or older, were included in this retrospective study. Subjects were divided in two groups: study group with postural changes (SG) and control group without postural changes (CG). Possible postural changes considered were scoliosis, kyphosis and lordosis. All women underwent BMD assessment and OA was identified at the region of the hip and lumbar spine by dual energy X-ray absorptiometry (DXA) analysis. Results SG was older (66.0 ± 7.3 years) than the CG (61.0 ± 8.6 years). In the entire sample we found thirteen women with OA and low BMD. Overall, the lumbar spine area was more affected by OA than the hip. The value of BMD T-score accounted for up to 77% of the changes observed in the SG group. Conclusion Postural changes identified in women are directly related to aging and associated with bone loss and joint degeneration. Postural changes may be the primary sign of frailty as a result of body adaptation to pain related to musculoskeletal diseases.

Is the skull responsive to bone mineralisation stimuli in children?

Whole-body-less-head (WBLH) is the recommended skeletal region of interest (ROI) for dual-energy X-ray absorptiometry (DXA) assessment of bone mineral density (BMD) in children. Historically it has been suggested that the skull is less responsive than the rest of the skeleton to stimuli that affect BMD but there are few published data to support this notion. We compared the associations of BMD with anthropometric, body composition, diet, and activity variables across various ROI. Children from the Southampton Women's Survey (SWS) mother-offspring cohort participated at age 6-7years, including measurement of height, weight, and whole-body and lumbar spine (LS) BMD by DXA (Hologic Discovery). Physical activity was assessed by accelerometry (Actiheart) and diet by interviewer-led questionnaire. BMD was measured in the following skeletal ROI: whole-body, skull, WBLH and lower limbs (all derived from the whole-body scan) and LS. 1218 children participated. Height z-score, weight z-score, lean mass and milk intake were associated with skull BMD, but associations were weaker than observed for other ROI; for example, the association between lean mass and skull BMD was β (95% CI) 0.11 (0.08, 0.14) SD/kg, compared with 0.32 (0.30, 0.34), 0.38 (0.37, 0.40) and 0.23 (0.21, 0.25) SD/kg for whole body, WBLH and lumbar spine, respectively. Relationships with whole-body BMD were attenuated compared with WBLH. Associations between skull BMD and anthropometry, body composition and dietary variables were weaker than for other DXA sites. These findings support, and importantly provide a quantitative basis for, the recommendation that the skull should be excluded from whole-body DXA analyses in children.

Official position of the Brazilian Association of Bone Assessment and Metabolism (ABRASSO) on the evaluation of body composition by densitometry: part I (technical aspects)\u2014general concepts, indications, acquisition, and analysis

ObjectiveTo review the technical aspects of body composition assessment by dual-energy X-ray absorptiometry (DXA) and other methods based on the most recent scientific evidence.Materials and methodsThis Official Position is a result of efforts by the Scientific Committee of the Brazilian Association of Bone Assessment and Metabolism (Associação Brasileira de Avaliação Óssea e Osteometabolismo, ABRASSO) and health care professionals with expertise in body composition assessment who were invited to contribute to the preparation of this document. The authors searched current databases for relevant publications. In this first part of the Official Position, the authors discuss the different methods and parameters used for body composition assessment, general principles of DXA, and aspects of the acquisition and analysis of DXA scans.ConclusionConsidering aspects of accuracy, precision, cost, duration, and ability to evaluate all three compartments, DXA is considered the gold-standard method for body composition assessment, particularly for the evaluation of fat mass. In order to ensure reliable, adequate, and reproducible DXA reports, great attention is required regarding quality control procedures, preparation, removal of external artifacts, imaging acquisition, and data analysis and interpretation.

Assessing the bone-healing potential of bone marrow mesenchymal stem cells in jawbone osteoporosis in albino rats.

Osteoporosis is one of the most common yet difficult to treat diseases. It affects millions of people and costs the health care systems billions worldwide. All of the available kinds of pharmacological treatment have multiple side effects, which is why a need for safer treatment options has emerged. This study aimed to assess the bone-healing potential of bone marrow mesenchymal stem cells (BM‑MSCs) in jawbone osteoporosis in Wistar albino rats. Osteoporosis was induced with a daily intraperitoneal injection of 200 μg/100 g dexamethasone for 1 month. The rats were then randomly distributed into 2 groups: the osteoporotic group (left untreated); and the BM‑MSCs group (received an intravenous injection of 50 million cultured BM‑MSCs). Half of the rats from each group were sacrificed 2 weeks and the other half 6 weeks after the introduction of treatment. Bone regeneration was assessed by means of dual-energy X-ray absorptiometry (DEXA), real-time polymerase chain reaction (RT‑PCR), as well as the histopathological and histomorphometric analyses. As for the 1st sacrifice time, there were no significant differences between the osteoporotic and BM‑MSCs groups with regard to all parameters except for bone mineral density (BMD), which was significantly higher in the BM‑MSCs group. Regarding the 2nd sacrifice time, the DEXA analysis showed a significant increase in BMD in the BM‑MSCs group (p < 0.001). The RT‑PCR analysis showed a significant decrease in RANKL gene expression (p < 0.001) and a significant increase in OPG gene expression (p < 0.001) in the BM‑MSCs group. In addition, the histopathological examination of the BM‑MSCs group showed pronounced healing progress in the jawbone microarchitecture. The histomorphometric analysis also revealed that the bone area percentage significantly increased in the BM‑MSCs group (p < 0.001). This study proved that BM‑MSCs could be effective in the treatment of osteoporosis.

111 Comparison of Hounsfield Units Versus T-Score in Predicting Postoperative Proximal Junctional Kyphosis

INTRODUCTION: Vertebral body (VB) bone quality is generally estimated indirectly via femoral neck dual-energy x-ray absorptiometry (DEXA) to counsel patients on their risk for development of proximal junctional kyphosis (PJK) after thoraco-lumbar fusion for adult spinal deformity. It is currently unknown whether direct measurement of VB bone quality through Hounsfield unit analysis (HUs) can successfully stratify patients on their risk of delayed complications. METHODS: 108 patients who underwent surgery for ASD were enrolled. Demographic characteristics, radiologic measurements, complication profile, and clinical outcomes were recorded both pre- and post-operatively. A Youden J-statistic was calculated based on an ROC analysis of the UIV Hounsfield unit data to give a single HU threshold to segregate patients into either a high or low HU group. Patient groups were then compared with respect to the mentioned clinical and radiographic outcome measures. RESULTS: Youden statistic revealed a HU threshold value of 126.8 for maximal group stratification. Significant change in proximal junctional cobb angle (PJCA) was observed between the low and high HU groups at one and two years (p &lt; 0.0001 and p = 0.0001 respectively). This was not similarly seen in hip or spine DEXA analysis (p &gt; 0.05). CONCLUSION: Assessment of bone quality via pre-operative measurement of the UIV VB HU can predict post-operative changes in PJCA. UIV HUs &lt; 126.8 are associated with 2.8x elevated risk of developing post-operative PJK. Current standard of care measurement of bone quality via femoral neck DEXA is of more limited utility compared to HU analysis.

The precision study of dual energy X-ray absorptiometry for bone mineral density and body composition measurements in female cynomolgus monkeys.

Dual-energy X-ray absorptiometry (DXA) is a well-accepted tool for monitoring skeletal and body composition changes in biomedical studies. The nonhuman primate model is suitable for studies exploring the pathogenesis of and novel treatments for osteoporosis. Our objectives are to determine the precision of DXA detection in cynomolgus monkeys and to identify the difference in precision in lumbar bone mineral density (BMD) with various segment selections. Thirty adult female cynomolgus monkeys underwent duplicate total body DXA scans. Total body bone mineral density (BMDTB) and body composition, including bone mineral content (BMCTB), lean mass (LMTB), and fat mass (FMTB), were analyzed by enCORE software, while lumbar BMD was obtained by manual region-of-interest analysis. The precision was represented as the root-mean-square standard deviation (RMS-SD) and coefficient of variation (RMS-CV%), and least significant changes (LSCs) were reported. The RMS-SD (RMS-CV%) of the repeated DXA analyses for BMDTB, BMCTB, LMTB and FMTB were 0.002 g/cm2 (0.50%), 0.90 g (0.42%), 0.015 kg (0.49%), and 0.031 kg (2.71%), respectively. The regional BMD precision (RMS-CV%) of the lumbar spine with various combinations ranged from 0.70% to 1.09%, The LSCs with 80% statistical confidence (LSC80) ranged from 1.27% to 1.97%, and LSC95 ranged from 1.94% to 3.01%. DXA provided excellent reproducibility in the measurements of BMD and body composition in nonhuman primates. We find DXA reliable for total and regional measurement in skeletal research and the evaluation of osteoporosis treatment with monkeys as animal models.