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Sample records for absorptiometry dxa method

  1. Three-dimensional X-ray absorptiometry (3D-XA): a method for reconstruction of human bones using a dual X-ray absorptiometry device.

    PubMed

    Kolta, S; Le Bras, A; Mitton, D; Bousson, V; de Guise, J A; Fechtenbaum, J; Laredo, J D; Roux, C; Skalli, W

    2005-08-01

    Three-dimensional accurate evaluation of the geometry of the proximal femur may be helpful for hip fracture risk evaluation. The purpose of this study was to apply and validate a stereo-radiographic 3D reconstruction method of the proximal femur, using contours identification from biplanar DXA images. Twenty-five excised human proximal femurs were investigated using a standard DXA unit. Three-dimensional personalized models were reconstructed using a dedicated non-stereo corresponding contours (NSCC) algorithm. Three-dimensional CT-scan reconstructions obtained on a clinical CT-scan unit were defined as geometric references for the comparison protocol, in order to assess accuracy and reproducibility of the 3D stereo-radiographic reconstructions. The precision of a set of 3D geometric parameters (femoral-neck axis length, mid-neck cross-section area, neck-shaft angle), obtained from stereo-radiographic models was also evaluated. This study shows that the NSCC method may be applied to obtain 3D reconstruction from biplanar DXA acquisitions. Applied to the proximal femur, this method showed good accuracy as compared with high-resolution personalized CT-scan models (mean error = 0.8 mm). Moreover, precision study for the set of 3D parameters yielded coefficients of variation lower than 5%. This is the first study providing 3D geometric parameters from standard 2D DXA images using the NSCC method. It has good accuracy and reproducibility in the present study on cadaveric femurs. In vivo prospective studies are needed to evaluate its discriminating potential on hip fracture risk prediction. PMID:15599494

  2. Efficiency of energy and protein deposition in swine measured by dual energy X-ray absorptiometry (DXA)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A series of studies were conducted using dual energy X-ray absorptiometry (DXA) to measure energy and protein deposition in pigs. In an initial validation study DXA was compared directly with slaughter analysis as a method for measuring body composition and energy deposition in pigs. Mean values fo...

  3. Bone geometry, structure and mineral distribution using Dual energy X ray Absorptiometry (DXA)

    NASA Technical Reports Server (NTRS)

    Whalen, Robert; Cleek, Tammy

    1993-01-01

    Dual energy x-ray absorptiometry (DXA) is currently the most widely used method of analyzing regional and whole body changes in bone mineral content (BMC) and areal (g/sq cm) bone mineral density (BMD). However, BMC and BMD do not provide direct measures of long bone geometry, structure, or strength nor do regional measurements detect localized changes in other regions of the same bone. The capabilities of DXA can be enhanced significantly by special processing of pixel BMC data which yields cross-sectional geometric and structural information. We have extended this method of analysis in order to develop non-uniform structural beam models of long bones.

  4. Dual energy X-ray absorptiometry (DXA): can it detect acute scaphoid fractures?

    PubMed

    Stephen, A B; Pye, D; Lyons, A R; Oni, J A; Davis, T R C

    2005-02-01

    This prospective study investigated whether dual energy X-ray absorptiometry (DXA) could detect acute scaphoid fractures. We blindly compared 10 normal and 10 fractured scaphoid images produced with a new technique of DXA scan analysis. This measured and plotted the density of the scaphoid throughout its length, producing a linear graph of the scaphoids' density instead of a single area (g/cm2) measurement of bone density. These new plots only detected six of the 10 fractures and suggested that four of the normal controls were fractured. Thus, this technique of DXA scan analysis is neither sensitive nor specific for the detection of acute scaphoid fractures. PMID:15620498

  5. Laser-Supported Dual Energy X-Ray Absorptiometry (DXL) Compared to Conventional Absorptiometry (DXA) and to FRAX as Tools for Fracture Risk Assessments

    PubMed Central

    Sääf, Maria; Strender, Lars-Erik; Nyren, Sven; Johansson, Sven-Erik

    2015-01-01

    Dual X-ray and Laser (DXL) adds a measure of the external thickness of the heel, measured by laser, to a conventional measurement of bone mineral density (BMD) of the calcaneus, using Dual energy X-ray Absorptiometry (DXA). The addition of heel thickness aims at a better separation of fatty tissue from bone than the standard method of DXA, which may mistake fatty tissue for bone and vice versa. The primary aim of this study was to evaluate whether DXL of the calcaneus can be used to assess the 10-year risk of fractures. Secondary aims were to compare the predictive ability of DXL with the two most established methods, Dual energy X-ray Absorptiometry (DXA) of the hip and spine and the WHO fracture risk assessment tool, FRAX. In 1999 a cohort of 388 elderly Swedish women (mean age 73.2 years) was examined with all three methods. Prospective fracture data was collected in 2010 from health care registers. One SD decrease in BMD of the heel resulted in an age-adjusted Hazard Ratio (HR) of 1.47 for a hip fracture (95% CI 1.09–1.98). Harrell’s C is the Cox regression counterpart of the Area Under Curve (AUC) of the Receiver Operating Characteristic (ROC) as a measure of predictive accuracy. Harrell’s C for BMD of the calcaneus was 0.65 for prediction of hip fractures. These results were not significantly different from those for BMD of the femoral neck or for FRAX. The HR for a hip fracture, for one SD decrease in BMD at the femoral neck, was 1.72 (95% CI 1.21–2.44. Harrell’s C was 0.67 for BMD at the femoral neck and 0.59 for FRAX. We conclude that DXL of the calcaneus could be a useful tool for fracture risk assessments. PMID:26413715

  6. Calcaneal quantitative ultrasound (QUS) and dual X-ray absorptiometry (DXA) bone analysis in adult HIV-positive patients.

    PubMed

    Clò, Alberto; Gibellini, Davide; Damiano, Davide; Vescini, Fabio; Ponti, Cristina; Morini, Silvia; Miserocchi, Anna; Musumeci, Giuseppina; Calza, Leonardo; Colangeli, Vincenzo; Viale, Pierluigi; Re, Maria Carla; Borderi, Marco

    2015-07-01

    Human immunodeficiency virus (HIV)-infected patients have an increased risk of developing osteopenia or osteoporosis compared with healthy individuals. Our aim was to compare dual X-ray absorptiometry (DXA), the gold standard for measuring bone mineral density (BMD), with bone quantitative ultrasound (QUS), an alternative technique for predicting fractures and screening low BMD, at least in postmenopausal populations. We analyzed DXA and QUS parameters to investigate their accuracy in the diagnosis and prediction of bone alterations in a cohort of 224 HIV-1-positive patients. The speed of sound (SOS), broadband ultrasound attenuation (BUA) and stiffness index (SI) parameters showed a moderate correlation with DXA, especially with total-body BMD (r coefficient of 0.38, 0.4 and 0.42 respectively), particularly in the female subgroup. In addition, multivariate analysis of HIV-positive patients assessed for vertebral fractures indicated that QUS was more effective than DXA at predicting the risk of fracture. QUS can be used as an additional tool for analyzing bone density in HIV-positive patients and its case of use and low cost make it especially suitable for resource-limited settings where DXA is not employed. PMID:26147144

  7. Should Dual-Energy X-ray Absorptiometry Technologists Estimate Dietary Calcium Intake at the Time of DXA?

    PubMed

    McKenna, Malachi J; McKenna, Mary Clare S; van der Kamp, Susan

    2016-01-01

    Adequate calcium intake is essential for bone health. Calcium is obtained from dietary sources and supplementation. Knowing the daily dietary calcium intake is helpful in deciding on the need for supplementation. Dietary calcium intake can be estimated quickly and accurately using an approach recommended by the National Osteoporosis Foundation. We sought to evaluate the usefulness of estimating dietary calcium intake by a technologist at the time of attendance for dual-energy X-ray absorptiometry (DXA) scanning. We conducted a retrospective survey of results on estimated dietary calcium intake in adults attending our DXA unit over 2 years (n=5569). We assessed intake with reference to the specifications of the Institute of Medicine according to sex and age. The average intake was 736 mg daily: Young adults had higher intakes than older adults (p<0.001), and men had higher intakes than women (p=0.017). According to Institute of Medicine's specification, we estimate that nearly 45% of Irish women need supplemental intake of 500 mg daily but <4% need supplemental intake of 1000 mg daily. Younger adults are apt to have intakes within, or higher than, the requirement. Having DXA technologists estimate dietary calcium intake at the time of DXA scanning may provide helpful information to the referring clinicians about the need for supplementation. PMID:25934029

  8. Accuracy of dual energy X-ray absorptiometry (DXA) in assessing carcass composition from different pig populations.

    PubMed

    Soladoye, O P; López Campos, Ó; Aalhus, J L; Gariépy, C; Shand, P; Juárez, M

    2016-11-01

    The accuracy of dual energy X-ray absorptiometry (DXA) in assessing carcass composition from pigs with diverse characteristics was examined in the present study. A total of 648 pigs from three different sire breeds, two sexes, two slaughter weights and three different diets were employed. DXA estimations were used to predict the dissected/chemical yield for lean and fat of carcass sides and primal cuts. The accuracy of the predictions was assessed based on coefficient of determination (R(2)) and residual standard deviation (RSD). The linear relationships for dissected fat and lean for all the primal cuts and carcass sides were high (R(2)>0.94, P<0.01), with low RSD (<1.9%). Relationships between DXA and chemical fat and lean of pork bellies were also high (R(2)>0.94, P<0.01), with RSD <2.9%. These linear relationships remained high over the full range of variation in the pig population, except for sire breed, where the coefficient of determination decreased when carcasses were classified based on this variable. PMID:27395824

  9. Segmental Musculoskeletal Examinations using Dual-Energy X-Ray Absorptiometry (DXA): Positioning and Analysis Considerations

    PubMed Central

    Hart, Nicolas H.; Nimphius, Sophia; Spiteri, Tania; Cochrane, Jodie L.; Newton, Robert U.

    2015-01-01

    Musculoskeletal examinations provide informative and valuable quantitative insight into muscle and bone health. DXA is one mainstream tool used to accurately and reliably determine body composition components and bone mass characteristics in-vivo. Presently, whole body scan models separate the body into axial and appendicular regions, however there is a need for localised appendicular segmentation models to further examine regions of interest within the upper and lower extremities. Similarly, inconsistencies pertaining to patient positioning exist in the literature which influence measurement precision and analysis outcomes highlighting a need for standardised procedure. This paper provides standardised and reproducible: 1) positioning and analysis procedures using DXA and 2) reliable segmental examinations through descriptive appendicular boundaries. Whole-body scans were performed on forty-six (n = 46) football athletes (age: 22.9 ± 4.3 yrs; height: 1.85 ± 0.07 cm; weight: 87.4 ± 10.3 kg; body fat: 11.4 ± 4.5 %) using DXA. All segments across all scans were analysed three times by the main investigator on three separate days, and by three independent investigators a week following the original analysis. To examine intra-rater and inter-rater, between day and researcher reliability, coefficients of variation (CV) and intraclass correlation coefficients (ICC) were determined. Positioning and segmental analysis procedures presented in this study produced very high, nearly perfect intra-tester (CV ≤ 2.0%; ICC ≥ 0.988) and inter-tester (CV ≤ 2.4%; ICC ≥ 0.980) reliability, demonstrating excellent reproducibility within and between practitioners. Standardised examinations of axial and appendicular segments are necessary. Future studies aiming to quantify and report segmental analyses of the upper- and lower-body musculoskeletal properties using whole-body DXA scans are encouraged to use the patient positioning and image analysis procedures outlined in this

  10. Cortical thickness estimation of the proximal femur from multi-view dual-energy X-ray absorptiometry (DXA)

    NASA Astrophysics Data System (ADS)

    Tsaousis, N.; Gee, A. H.; Treece, G. M.; Poole, K. E. S.

    2013-02-01

    Hip fracture is the leading cause of acute orthopaedic hospital admission amongst the elderly, with around a third of patients not surviving one year post-fracture. Although various preventative therapies are available, patient selection is difficult. The current state-of-the-art risk assessment tool (FRAX) ignores focal structural defects, such as cortical bone thinning, a critical component in characterizing hip fragility. Cortical thickness can be measured using CT, but this is expensive and involves a significant radiation dose. Instead, Dual-Energy X-ray Absorptiometry (DXA) is currently the preferred imaging modality for assessing hip fracture risk and is used routinely in clinical practice. Our ambition is to develop a tool to measure cortical thickness using multi-view DXA instead of CT. In this initial study, we work with digitally reconstructed radiographs (DRRs) derived from CT data as a surrogate for DXA scans: this enables us to compare directly the thickness estimates with the gold standard CT results. Our approach involves a model-based femoral shape reconstruction followed by a data-driven algorithm to extract numerous cortical thickness point estimates. In a series of experiments on the shaft and trochanteric regions of 48 proximal femurs, we validated our algorithm and established its performance limits using 20 views in the range 0°-171°: estimation errors were 0:19 +/- 0:53mm (mean +/- one standard deviation). In a more clinically viable protocol using four views in the range 0°-51°, where no other bony structures obstruct the projection of the femur, measurement errors were -0:07 +/- 0:79 mm.

  11. Relationships among dual-energy X-ray absorptiometry (DXA), bioelectrical impedance (BIA), and ultrasound measurements of body composition of swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In three separate studies (156 pigs total), DXA, BIA, and ultrasound were compared as methods for measuring live body composition of pigs at 60 and 100-110 kg BWt. DXA measured total body fat and lean content, BIA measurements of resistance (Rs) and reactance (Xc) were used to calculate total body l...

  12. Comparison of DXA and MRI methods for interpreting femoral neck bone mineral density.

    PubMed

    Arokoski, Merja H; Arokoski, Jari P A; Vainio, Pauli; Niemitukia, Lea H; Kröger, Heikki; Jurvelin, Jukka S

    2002-01-01

    The aim of the study was to improve the practical implementation of the dual X-ray absorptiometry (DXA) by converting the areal bone mineral density BMD (BMD(areal)) to volumetric BMD using magnetic resonance (MR) imaging (MRI) because a failure to control for the femoral neck size can lead to erroneous interpretation of BMD values. We also evaluated the feasibility of MR T2* relaxation time in assessing bone mineral status of the femoral neck. Twenty-eight randomly selected 47- to 64-yr-old healthy men were studied. The men had neither unilateral nor bilateral hip osteoarthritis according to radiographs. Bone width, mineral content (BMC), BMD(areal), and apparent volumetric BMD (BMD(vol)) of the right femoral neck were measured with DXA. The BMD(vol) was calculated by approximating the femoral neck to be cylindrical with a circular cross-section (Vol(dxa)). Volumetric measurements from MR (Vol(mri)) images of the femoral neck were also used to create a BMD measure that was corrected for the femoral neck volume (BMD(mri)). T2* measurements were performed with a 1.5-T scanner (Siemens Magnetom 63SP, Erlangen, Germany). A single 10-mm-thick coronal slice was generated on the femur with a repetition time of 60 ms, and nine echo times (4-20 ms) were used to derive T2* values. Vol(mri) correlated positively (r = 0.828, p < 0.001) with Vol(dxa). However, the Vol(mri) of the femoral neck was 18% lower than the Vol(dxa). Similarly, the BMD(mri) was related to the BMD(vol) (r = 0.737, p < 0.001). Because of the difference in the volumetric measures, the BMD(mri) of the femoral neck was 21% higher than the BMD(vol) (p < 0.001). T2* relaxation time showed a significant negative correlation with BMC, BMD(areal), BMD(vol), and BMD(mri) (r = -0.423 to -0.757, p < 0.05-0.001). In conclusion, these results are evidence that DXA-derived volume approximations by the cylinder with circular cross-section geometry may lead to lower DXA-derived BMD(vol) values, as compared to true MRI

  13. Volumetric measurements of bone mineral density of the lumbar spine: comparison of three geometrical approximations using dual-energy X-ray absorptiometry (DXA)

    PubMed

    Schreuder, M F; van Driel, A P; van Lingen, A; Roos, J C; de Ridder, C M; Manoliu, R A; David, E F; Netelenbos, J C

    1998-08-01

    Measurements of bone mineral density using dual-energy X-ray absorptiometry (DXA) gives area values (g cm-2) rather than true volumetric values (g cm-3). To calculate the vertebral volume using planar postero-anterior and lateral DXA values, several different geometrical approximations were used: cubic, cylindrical with a circular cross-section and cylindrical with an elliptical cross-section. The aim of this study was to compare these geometrical approximations with each other and with a reference standard, defined as the volume found on a computed tomographic (CT) scan. L2 and L3 were evaluated in a phantom study. Volume approximations by the cube or cylinder with circular cross-section geometry showed more than a 50% overestimation (range 54-74%). However, the elliptical cylinder approach showed very good agreement: 2.1% and 1.2% for L2 and L3, respectively, when compared to the CT volumes. In addition, we performed four patient studies with both CT and DXA to evaluate the elliptical cylinder estimate in a clinical setting. For L2 and L3, the mean relative difference was less than 2%. We conclude that the elliptical cylinder approach results in the most accurate bone volume estimates in both the phantom and patients. PMID:9751926

  14. DXA: Technical aspects and application.

    PubMed

    Bazzocchi, Alberto; Ponti, Federico; Albisinni, Ugo; Battista, Giuseppe; Guglielmi, Giuseppe

    2016-08-01

    The key role of dual-energy X-ray absorptiometry (DXA) in the management of metabolic bone diseases is well known. The role of DXA in the study of body composition and in the clinical evaluation of disorders which directly or indirectly involve the whole metabolism as they may induce changes in body mass and fat percentage is less known or less understood. DXA has a range of clinical applications in this field, from assessing associations between adipose or lean mass and the risk of disease to understanding and measuring the effects of pathophysiological processes or therapeutic interventions, in both adult and paediatric human populations as well as in pre-clinical settings. DXA analyses body composition at the molecular level that is basically translated into a clinical model made up of fat mass, non-bone lean mass, and bone mineral content. DXA allows total and regional assessment of the three above-mentioned compartments, usually by a whole-body scan. Since body composition is a hot topic today, manufacturers have steered the development of DXA technology and methodology towards this. New DXA machines have been designed to accommodate heavier and larger patients and to scan wider areas. New strategies, such as half-body assessment, permit accurate body scan and analysis of individuals exceeding scan field limits. Although DXA is a projective imaging technique, new solutions have recently allowed the differential estimate of subcutaneous and intra-abdominal visceral fat. The transition to narrow fan-beam densitometers has led to faster scan times and better resolution; however, inter- or intra-device variation exists depending on several factors. The purposes of this review are: (1) to appreciate the role of DXA in the study of body composition; (2) to understand potential limitations and pitfalls of DXA in the analysis of body composition; (3) to learn about technical elements and methods, and to become familiar with biomarkers in DXA. PMID:27157852

  15. Accuracy of DXA in estimating body composition changes in elite athletes using a four compartment model as the reference method

    PubMed Central

    2010-01-01

    Background Dual-energy x-ray absorptiometry (DXA) provides an affordable and practical assessment of multiple whole body and regional body composition. However, little information is available on the assessment of changes in body composition in top-level athletes using DXA. The present study aimed to assess the accuracy of DXA in tracking body composition changes (relative fat mass [%FM], absolute fat mass [FM], and fat-free mass [FFM]) of elite male judo athletes from a period of weight stability to prior to a competition, compared to a four compartment model (4C model), as the criterion method. Methods A total of 27 elite male judo athletes (age, 22.2 ± 2.8 yrs) athletes were evaluated. Measures of body volume by air displacement plethysmography, bone mineral content assessed by DXA, and total-body water assessed by deuterium dilution were used in a 4C model. Statistical analyses included examination of the coefficient of determinant (r2), standard error of estimation (SEE), slope, intercept, and agreement between models. Results At a group level analysis, changes in %FM, FM, and FFM estimates by DXA were not significantly different from those by the 4C model. Though the regression between DXA and the 4C model did not differ from the line of identity DXA %FM, FM, and FFM changes only explained 29%, 36%, and 38% of the 4C reference values, respectively. Individual results showed that the 95% limits of agreement were -3.7 to 5.3 for %FM, -2.6 to 3.7 for FM, and -3.7 to 2.7 for FFM. The relation between the difference and the mean of the methods indicated a significant trend for %FM and FM changes with DXA overestimating at the lower ends and underestimating at the upper ends of FM changes. Conclusions Our data indicate that both at group and individual levels DXA did not present an expected accuracy in tracking changes in adiposity in elite male judo athletes. PMID:20307312

  16. Prenatal pesticide exposure and PON1 genotype associated with adolescent body fat distribution evaluated by dual X-ray absorptiometry (DXA).

    PubMed

    Tinggaard, J; Wohlfahrt-Veje, C; Husby, S; Christiansen, L; Skakkebaek, N E; Jensen, T K; Grandjean, P; Main, K M; Andersen, H R

    2016-07-01

    Many modern pesticides have endocrine disrupting abilities and early-life exposure may affect growth and disease risk later in life. Previously, we reported associations between prenatal pesticide exposure and higher childhood body fat content measured by anthropometry. The associations were affected by child PON1 Q192R genotype. We aimed to study whether prenatal pesticide exposure was still associated with body fat content and distribution in the children at puberty and the potential impact of both maternal and child PON1 Q192R genotype. In this prospective cohort study of 247 children born by occupationally exposed or unexposed women (greenhouse workers and controls) two follow-up examinations (age 10-15 and 11-16 years) including simple anthropometry, skinfold measurements, pubertal staging and blood sampling were performed. Total and regional fat% was determined by dual X-ray absorptiometry (DXA) at age 10-15. Prenatal pesticide exposure was associated with increased total, android, and gynoid fat percentage (DXA) at age 10-15 years after adjustment for sex, socioeconomic status, and puberty (all β = 0.5 standard deviation score (SDS) p < 0.05). Stratified by sex, the associations were significant in girls (total fat: β = 0.7 SDS, android-gynoid ratio: β = 0.1, both p < 0.05), but not in boys. Carrying the R-allele (child or mother, separately, or both) augmented the differences between exposed and unexposed children (total fat: β = 1.0 SDS, β = 0.8 SDS, p < 0.05, respectively, and β = 1.2 SDS, p < 0.01). No exposure-related differences were found if either the child or mother had the QQ wild-type. At age 11-16, exposed children tended to have a higher total fat% estimated by skinfolds than unexposed children (p = 0.06). No significant associations between prenatal exposure and body mass index or waist circumference were found. Prenatal pesticide exposure was associated with higher adolescent body fat content, including android

  17. DXA: Can it be used as a criterion reference for body fat measurements in children?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dual-energy X-ray absorptiometry (DXA) is often cited as a criterion method for body composition measurements. We have previously shown that a new DXA software version (Hologic Discovery V12.1) will affect whole-body bone mineral results for subjects weighing less than 40 kg. We wished to re-analy...

  18. Assessment of adiposity in psoriatic patients by dual energy X-ray absorptiometry compared to conventional methods*

    PubMed Central

    Diniz, Michelle dos Santos; Bavoso, Nádia Couto; Kakehasi, Adriana Maria; Lauria, Márcio Weissheimer; Soares, Maria Marta Sarquis; Machado-Pinto, Jackson

    2016-01-01

    BACKGROUND Obesity is considered a chronic low-grade inflammatory disease that shares mediators of inflammation with psoriasis, such as TNF-α and IL-6. The relationship between these two conditions involves factors such as predisposition and response to therapy, in addition to an association with cardiovascular disease. OBJECTIVES The aim of the present study was to investigate the prevalence of adiposity as determined by body mass index (BMI), waist circumference (WC), and dual energy X-ray absorptiometry (DXA) evaluation in patients with psoriasis. METHODS BMI, WC and body composition by DXA were measured in 42 psoriatic patients without joint complaints and in 41 control patients using standard procedures. In the comparison between cases and controls, we used Pearson’s Χ2 test or Fisher’s exact test, and the nonparametric Mann-Whitney test. The difference between the diverse classification methods for obesity was evaluated using McNemar’s test. To test the level of agreement between those variables, we used the weighted kappa coefficient. RESULTS There was no difference in the prevalence of obesity among cases and controls. Both BMI and WC had low agreement with measures of body fat evaluated by DXA. With the use of DXA scanning, prevalence of overweight and obesity in patients with psoriasis was 83.3%, which constitutes a strong evidence of the need for intervention on this metabolic parameter. CONCLUSION Dual energy X-ray absorptiometry was more capable of identifying obesity compared with BMI and WC both in psoriatic and control patients. PMID:27192512

  19. Bone mineral density of skeletal remains: Discordant results between chemical analysis and DXA method.

    PubMed

    Sutlovic, Davorka; Boric, Igor; Sliskovic, Livia; Popovic, Marijana; Knezovic, Zlatka; Nikolic, Ivana; Vucinovic, Ana; Vucinovic, Zoran

    2016-05-01

    Dual-energy X-ray absorptiometry (DXA) scanning is a gold standard for bone mineral density measurement and diagnosis of primary and secondary osteoporosis in living persons. DXA is becoming widespread when analysing archaeological material, and is considered to provide an accurate diagnosis of osteoporosis in skeletal samples. The aim of this study was to explain the differences in results between bone mineral density (obtained with DXA) and chemical determination of calcium and phosphorus concentrations in skeletal remains. We examined bone mineral density (BMD) and mineral content of femoral bone samples exhumed from mass graves of the Second World War. BMD was determined by Hologic QDR 4500 C (S/N 48034) Bone Densitometer. Concentrations of calcium and phosphorus were determined with AAS (Atomic absorption spectroscopy) and UV/VIS (Ultraviolet-visible) spectroscopy. The results obtained in this study do not support the hypothesis according to which BMD measured by DXA scan has positive correlation with chemically determined concentrations of calcium and phosphorus in bones, especially in acidic soils where there was significant impact of diagenesis observed. PMID:27161916

  20. Pediatric DXA: technique and interpretation

    PubMed Central

    Henwood, Maria J.

    2006-01-01

    This article reviews dual X-ray absorptiometry (DXA) technique and interpretation with emphasis on the considerations unique to pediatrics. Specifically, the use of DXA in children requires the radiologist to be a “clinical pathologist” monitoring the technical aspects of the DXA acquisition, a “statistician” knowledgeable in the concepts of Z-scores and least significant changes, and a “bone specialist” providing the referring clinician a meaningful context for the numeric result generated by DXA. The patient factors that most significantly influence bone mineral density are discussed and are reviewed with respect to available normative databases. The effects the growing skeleton has on the DXA result are also presented. Most important, the need for the radiologist to be actively involved in the technical and interpretive aspects of DXA is stressed. Finally, the diagnosis of osteoporosis should not be made on DXA results alone but should take into account other patient factors. PMID:16715219

  1. A study on the effects of a calcium drug on the bone mineral density (BMD) by using dual-energy X-ray Absorptiometry (DXA)

    NASA Astrophysics Data System (ADS)

    Kim, Eun-Hye; Kim, Ho-Sung; Dong, Kyung-Rae; Park, Yong-Soon; Chung, Woon-Kwan; Cho, Jae-Hwan

    2012-12-01

    Measurements of osteoporosis might contain errors caused by the calcium drug used in the prevention and the treatment of osteoporosis. This study conducted a lumbar spine phantom experiment to examine whether a calcium drug can influence the measured values of the bone mineral density (BMD) because of the drug taken by a real patient remaining undigested in the stomach. Dual-energy X-ray Absorptiometry (DXA) was used to measure the BMD for a calcium-drug in an equipment-dedicated lumbar spine phantom and 10 patients selected for the BMD measurement. Three types of drugs that are prescribed in actual clinical practice calcium drugs were used for the phantom experiment, and the drugs were divided into a fixed dose, 1/2 of the fixed dose, 1/4 of the fixed dose and 1/8 of the fixed dose. Without the drugs included, the phantom was scanned 60 times continuously to calculate the baseline BMD. The BMD was measured as the calcium drug coated with paraffin was placed in the lumbar vertebra 2 and the soft tissue region of the phantom. To determine when the drug was invisible to the naked eye are measured, the BMD at different drug dilutions. The measurements were conducted three times to calculate the mean. In the patient experiment, patients were selected who visited hospital after taking the drug before measuring the BMD. After a certain time had passed, the BMD was measured again to examine the difference in images and the change in BMD values due to the calcium-drug intake. The BMD measurements of lumbar 1-4 in the phantom were higher, with statistical significant, than the least significant change (LSC) in the bone region for all three drugs (Ca carbonate, Ca citrate and Ca cholecalciferol), showing a significant increase. On the other hand, there was no significant change in the soft tissue. When Ca Cholecalciferol was used in a fixed dose, the BMD of L2 increased by 11.6%, showing the largest increase among the drugs examined, but only a 2.8% increase in the BMD of L1

  2. Measurement of the body composition of small piglets by quantitative magnetic resonance (QMR) and dual-energy X-ray absorptiometry (DXA)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During studies of the growth of neonatal piglets it is important to be able to accurately assess changes in body composition. The purpose of this study was to compare the in vivo measurements of body composition of small piglets using QMR and DXA and to validate those results by chemical analysis. A...

  3. Body Segment Inertial Parameters of elite swimmers Using DXA and indirect Methods

    PubMed Central

    Rossi, Marcel; LYTTLE, Andrew; EL-SALLAM, Amar; BENJANUVATRA, Nat; BLANKSBY, Brian

    2013-01-01

    As accurate body segment inertial parameters (BSIPs) are difficult to obtain in motion analysis, this study computed individual BSIPs from DXA scan images. Therefore, by co-registering areal density data with DXA grayscale image, the relationship between pixel color gradient and the mass within the pixel area could be established. Thus, one can calculate BSIPs, including segment mass, center of mass (COM) and moment of inertia about the sagittal axis (Ixx). This technique calculated whole body mass very accurately (%RMSE of < 1.5%) relatively to results of the generic DXA scanner software. The BSIPs of elite male and female swimmers, and young adult Caucasian males (n = 28), were computed using this DXA method and 5 other common indirect estimation methods. A 3D surface scan of each subject enabled mapping of key anthropometric variables required for the 5 indirect estimation methods. Mass, COM and Ixx were calculated for seven body segments (head, trunk, head + trunk, upper arm, forearm, thigh and shank). Between-group comparisons of BSIPs revealed that elite female swimmers had the lowest segment masses of the three groups (p < 0.05). Elite male swimmers recorded the greatest inertial parameters of the trunk and upper arms (p < 0.05). Using the DXA method as the criterion, the five indirect methods produced errors greater than 10% for at least one BSIP in all three populations. Therefore, caution is required when computing BSIPs for elite swimmers via these indirect methods, DXA accurately estimated BSIPs in the frontal plane. Key Points Elite swimmers have significantly different body segment inertial parameters than young adult Caucasian males. The errors computed from indirect BSIP estimation methods are large regardless whether applied to elite swimmers or young adult Caucasian males. No indirect estimation method consistently performed best. PMID:24421737

  4. Body Fat Mass Assessment: A Comparison between an Ultrasound-Based Device and a Discovery A Model of DXA

    PubMed Central

    Pineau, Jean-Claude; Lalys, Loïc; Pellegrini, Massimo; Battistini, Nino Carlo

    2013-01-01

    Objective. To examine measurement of body composition by ultrasound compared with a reference technique:dual energy X-ray absorptiometry (DXA). We evaluated the accuracy of a portable ultrasound-based device in estimating total body fat mass with those assessed by DXA in adult. Methods. Body fat mass has been estimated using a portable ultrasound-based device in comparison with a contemporary reference DXA apparatus: the Hologic Discovery A. Anthropometric data has been assessed in order to maximize the output of the software associated with the ultrasound-based device. A cross-validation between ultrasound technique (US) and DXA was developed in this study. Total body fat mass estimated by ultrasound was compared with this DXA model in a sample of 83 women and 41 men. Results. Ultrasound technique (US) of body fat (BF) was better correlated with DXA in both women (r2 = 0.97, P < 0.01) and men (r2 = 0.92, P < 0.01) with standard errors of estimates (SEE) being 2.1 kg and 2.2 kg, respectively. Conclusion. The use of a portable device based on a US produced a very accurate BF estimate in relation to DXA reference technique. As DXA absorptiometry techniques are not interchangeable, the use of our ultrasound-based device needs to be recalibrated on a more contemporary DXA. PMID:24575315

  5. In vivo measurement of body composition of chickens using quantitative magnetic resonance (QMR)and dual x-ray absorptiometry (DXA)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    QMR is a nuclear magnetic resonance based method for measuring the fat, lean and water content of the total body of the live animal. The purpose of this study was to evaluate the use of QMR for measuring the body composition of chickens while comparing QMR results to those obtained by dual X-ray ab...

  6. DXA parameters: beyond bone mineral density.

    PubMed

    Briot, Karine

    2013-05-01

    Dual-energy X-ray absorptiometry (DXA) is the reference standard for measuring bone mineral density (BMD) to diagnose osteoporosis. However, BMD measurement alone does not reliably predict the fracture risk. DXA can be used to assess other parameters (e.g. presence of vertebral fractures, bone microarchitecture, bone geometry, and body composition) simultaneously with BMD measurements, to help identify individuals at high fracture risk. Among these parameters, some are suitable for use in clinical practice, whereas others are reserved for research. Vertebral fracture assessment (VFA) is a very low radiation-dose method for detecting thoracic and lumbar vertebral fractures. Compared to standard radiography, VFA can be used in a broader population to detect asymptomatic vertebral fractures. The very good negative predictive value of VFA leads, in one-third of cases, to changes in patient management (drug treatment and prescription of radiographs). The trabecular bone score (TBS) is a noninvasively measured texture parameter that correlates with 3D bone microarchitecture parameters independently from BMD and that can be determined from lumbar-spine DXA images. Several cross-sectional studies and a prospective study established that the TBS was effective in identifying individuals with fractures. Additional studies will have to be performed to determine whether TBS determination can be recommended for everyday practice when treatment decisions are difficult. PMID:23622733

  7. Correlation between the values of bone measurements using DXA, QCT and USD methods and the bone strength in calcanei in vitro.

    PubMed

    Imamoto, K; Hamanaka, Y; Yamamoto, I; Niiho, C

    1998-10-01

    In this study we used the calcanei from 32 female and 29 male cadavers, ages 58 to 100. The bone mineral density (BMD) and average bone density (ABD) were measured using dual energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT) respectively, while speed of sound (SOS), broadband ultrasound attenuation (BUA) and stiffness index (SI) were measured using ultrasound densitometry (USD). Thereafter, the bone strength was measured using a compressor to cause bone fracture, and evaluated in comparison with the values of the three measurement methods. The scatter diagrams of the values of the three different methods versus age displayed a negative linear regression in both sexes. Values for BMD and ABD were generally about 20% higher in males than in females, while SOS, BUA and SI were a few percents higher in males than in females. A significantly high correlation existed between BMD and ABD (r = 0.95), and a moderate correlation between BMD and either SOS, BUA or SI (r = 0.65; r = 0.39; r = 0.57, respectively). Thus, among the values measured using USD, SOS most closely corresponded to BMD of the calcanei. The bone strength of the calcanei indicated a moderate correlation with BMD, ABD and SOS (r = 0.38, P < 0.01; r = 0.43, P < 0.001; r = 0.45, P < 0.001, respectively). However, 42 calcanei fractured under pressures of less than 40 kgf, although the other 19 calcanei endured pressure of 40 kgf or more. Two calcanei with high BMD over 0.7 g/cm2 by DXA were very fragile, whereas a few with low BMD less than 0.4 g/cm2 were not very fragile. Similarly, high SOS, BUA and SI values by USD did not always correspond to high bone strength. Thus, some discrepancies among the bone strength and measurement values remained to be solved in the future. PMID:9844342

  8. Comparison of DXA and CT in the assessment of body composition in premenopausal women with obesity and anorexia nervosa.

    PubMed

    Bredella, Miriam A; Ghomi, Reza Hosseini; Thomas, Bijoy J; Torriani, Martin; Brick, Danielle J; Gerweck, Anu V; Misra, Madhusmita; Klibanski, Anne; Miller, Karen K

    2010-11-01

    Accurate methods for assessing body composition in subjects with obesity and anorexia nervosa (AN) are important for determination of metabolic and cardiovascular risk factors and to monitor therapeutic interventions. The purpose of our study was to assess the accuracy of dual-energy X-ray absorptiometry (DXA) for measuring abdominal and thigh fat, and thigh muscle mass in premenopausal women with obesity, AN, and normal weight compared to computed tomography (CT). In addition, we wanted to assess the impact of hydration on DXA-derived measures of body composition by using bioelectrical impedance analysis (BIA). We studied a total of 91 premenopausal women (34 obese, 39 with AN, and 18 lean controls). Our results demonstrate strong correlations between DXA- and CT-derived body composition measurements in AN, obese, and lean controls (r = 0.77-0.95, P < 0.0001). After controlling for total body water (TBW), the correlation coefficients were comparable. DXA trunk fat correlated with CT visceral fat (r = 0.51-0.70, P < 0.0001). DXA underestimated trunk and thigh fat and overestimated thigh muscle mass and this error increased with increasing weight. Our study showed that DXA is a useful method for assessing body composition in premenopausal women within the phenotypic spectrum ranging from obesity to AN. However, it is important to recognize that DXA may not accurately assess body composition in markedly obese women. The level of hydration does not significantly affect most DXA body composition measurements, with the exceptions of thigh fat. PMID:20111013

  9. Correlation of visceral adipose tissue measured by Lunar Prodigy dual X-ray absorptiometry with MRI and CT in older men.

    PubMed

    Cheung, A S; de Rooy, C; Hoermann, R; Gianatti, E J; Hamilton, E J; Roff, G; Zajac, J D; Grossmann, M

    2016-08-01

    Quantification of abdominal visceral adipose tissue (VAT) is important to understand obesity-related comorbidities. We hypothesized that dual X-ray absorptiometry (DXA) measurements of VAT would correlate with traditional gold standards of magnetic resonance imaging (MRI) and computed tomography (CT) in older men. Deming regression and Bland-Altman plots were used to assess the agreement between VAT measured simultaneously by DXA and MRI (n=95) in a cohort of older males participating in a randomized trial of testosterone replacement for diabetes. We also correlated DXA with single-slice CT (n=102) in a cohort of older males undergoing testosterone deprivation for prostate cancer. Lunar Prodigy DXA scanners using enCORE software was used to measure VAT. DXA VAT volume strongly correlated with MRI VAT volume (r=0.90, P<0.0001) and CT VAT area (r=0.83, P<0.0001). As DXA assesses VAT volume in a smaller compartment than MRI, Bland-Altman analysis demonstrated DXA systematically underestimated VAT by an approximately 30% proportional bias. DXA VAT volume measured by Lunar Prodigy DXA scanners correlate well with gold standard MRI and CT quantification methods, and provides a low radiation, efficient, cost-effective option. Future clinical studies examining the effects of interventions on body composition and regional fat distribution may find DXA an appropriate volumetric method to quantify VAT. PMID:27003112

  10. Total-body calcium estimated by delayed gamma neutron activation analysis and dual-energy X-ray absorptiometry.

    PubMed

    Aloia, J F; Ma, R; Vaswani, A; Feuerman, M

    1999-01-01

    Total body calcium (TBCa) in 270 black and white women age 21-79 years was measured concurrently by delayed gamma neutron activation analysis (DGNA) and dual-energy X-ray absorptiometry (DXA). The mean value for TBCa calculated from DXA was 933 g compared with 730 g for DGNA. By regression, TBCa(DXA(g)) = 1.35 x TBCa(DGNA(g)) -54 (r = 0. 90, r(2) = 81.4%, SEE = 66.9 g). This remarkable difference of 203 g suggests that one or both these methods is not accurate. Adjustment of the regression of DXA versus DGNA for body mass index or trunk thickness explained 8.5-10% of the variability between methods. The unadjusted slope for the DXA values regressed against the DGNA values was 1.35, indicating significant discordance between the methods. There is greater agreement between the two DGNA facilities (Brookhaven National Laboratory and Baylor College of Medicine) and between the various DXA instruments. Either DGNA underestimates TBCa or DXA overestimates total-body bone mineral content. Resolution of these disparate results may possibly be achieved by concurrent measurement of whole human cadavers of different sizes with chemical determination of the calcium content of the ash. In the interim, cross-calibration equations between DGNA and standardized values for DXA for total-body bone mineral content may be used, which will permit reporting of consistent values for TBCa from the two technologies. PMID:10663353

  11. Assessment of Bone Mineral Density in Male Patients with Chronic Obstructive Pulmonary Disease by DXA and Quantitative Computed Tomography

    PubMed Central

    Fountoulis, George; Kerenidi, Theodora; Kokkinis, Constantinos; Georgoulias, Panagiotis; Thriskos, Paschal; Gourgoulianis, Konstantinos; Fezoulidis, Ioannis; Vassiou, Katerina

    2016-01-01

    The purpose of this study is to identify the prevalence of osteoporosis in male patients with chronic obstructive pulmonary disease (COPD) by dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT) and to compare the diagnostic abilities of the above methods. Thirty-seven male patients with established COPD were examined with DXA and standard QCT in lumbar spine, including L1, L2, and L3 vertebrae. T-scores and bone mineral density values were calculated by DXA and QCT method, respectively. Comparative assessment of the findings was performed and statistical analysis was applied. QCT measurements found more COPD patients with impaired bone mineral density compared to DXA, namely, 13 (35.1%) versus 12 (32.4%) patients with osteopenia and 16 (43.2%) versus 9 (16.2%) patients with osteoporosis (p = 0.04). More vertebrae were found with osteoporosis by QCT compared to DXA (p = 0.03). The prevalence of osteoporosis among male patients with COPD is increased and DXA may underestimate this risk. QCT measurements have an improved discriminating ability to identify low BMD compared to DXA measurements because QCT is able to overcome diagnostic pitfalls including aortic calcifications and degenerative spinal osteophytes. PMID:27087809

  12. Assessment of Bone Mineral Density in Male Patients with Chronic Obstructive Pulmonary Disease by DXA and Quantitative Computed Tomography.

    PubMed

    Fountoulis, George; Kerenidi, Theodora; Kokkinis, Constantinos; Georgoulias, Panagiotis; Thriskos, Paschal; Gourgoulianis, Konstantinos; Fezoulidis, Ioannis; Vassiou, Katerina; Vlychou, Marianna

    2016-01-01

    The purpose of this study is to identify the prevalence of osteoporosis in male patients with chronic obstructive pulmonary disease (COPD) by dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT) and to compare the diagnostic abilities of the above methods. Thirty-seven male patients with established COPD were examined with DXA and standard QCT in lumbar spine, including L1, L2, and L3 vertebrae. T-scores and bone mineral density values were calculated by DXA and QCT method, respectively. Comparative assessment of the findings was performed and statistical analysis was applied. QCT measurements found more COPD patients with impaired bone mineral density compared to DXA, namely, 13 (35.1%) versus 12 (32.4%) patients with osteopenia and 16 (43.2%) versus 9 (16.2%) patients with osteoporosis (p = 0.04). More vertebrae were found with osteoporosis by QCT compared to DXA (p = 0.03). The prevalence of osteoporosis among male patients with COPD is increased and DXA may underestimate this risk. QCT measurements have an improved discriminating ability to identify low BMD compared to DXA measurements because QCT is able to overcome diagnostic pitfalls including aortic calcifications and degenerative spinal osteophytes. PMID:27087809

  13. Bone age assessment by dual-energy X-ray absorptiometry in children: an alternative for X-ray?

    PubMed Central

    Heppe, D H M; Taal, H R; Ernst, G D S; Van Den Akker, E L T; Lequin, M M H; Hokken-Koelega, A C S; Geelhoed, J J M; Jaddoe, V W V

    2012-01-01

    Objective The aim of the study was to validate dual-energy X-ray absorptiometry (DXA) as a method to assess bone age in children. Methods Paired dual-energy X-ray absorptiometry (DXA) scans and X-rays of the left hand were performed in 95 children who attended the paediatric endocrinology outpatient clinic of University Hospital Rotterdam, the Netherlands. We compared bone age assessments by DXA scan with those performed by X-ray. Bone age assessment was performed by two blinded observers according to the reference method of Greulich and Pyle. Intra-observer and interobserver reproducibility were investigated using the intraclass correlation coefficient (ICC), and agreement was tested using Bland and Altman plots. Results The intra-observer ICCs for both observers were 0.997 and 0.991 for X-ray and 0.993 and 0.987 for DXA assessments. The interobserver ICC was 0.993 and 0.991 for X-ray and DXA assessments, respectively. The mean difference between bone age assessed by X-ray and DXA was 0.11 years. The limits of agreement ranged from −0.82 to 1.05 years, which means that 95% of all differences between the methods were covered by this range. Conclusions Results of bone age assessment by DXA scan are similar to those obtained by X-ray. The DXA method seems to be an alternative for assessing bone age in a paediatric hospital-based population. PMID:21586503

  14. Fundamental Movement Skill Proficiency and Body Composition Measured by Dual Energy X-Ray Absorptiometry in Eight-Year-Old Children

    ERIC Educational Resources Information Center

    Slotte, Sari; Sääkslahti, Arja; Metsämuuronen, Jari; Rintala, Pauli

    2015-01-01

    Objective: The main aim was to examine the association between fundamental movement skills (FMS) and objectively measured body composition using dual energy X-ray absorptiometry (DXA). Methods: A study of 304 eight-year-old children in Finland. FMS were assessed with the "Test of gross motor development," 2nd ed. Total body fat…

  15. Non-invasive methods for the determination of body and carcass composition in livestock: dual-energy X-ray absorptiometry, computed tomography, magnetic resonance imaging and ultrasound: invited review.

    PubMed

    Scholz, A M; Bünger, L; Kongsro, J; Baulain, U; Mitchell, A D

    2015-07-01

    The ability to accurately measure body or carcass composition is important for performance testing, grading and finally selection or payment of meat-producing animals. Advances especially in non-invasive techniques are mainly based on the development of electronic and computer-driven methods in order to provide objective phenotypic data. The preference for a specific technique depends on the target animal species or carcass, combined with technical and practical aspects such as accuracy, reliability, cost, portability, speed, ease of use, safety and for in vivo measurements the need for fixation or sedation. The techniques rely on specific device-driven signals, which interact with tissues in the body or carcass at the atomic or molecular level, resulting in secondary or attenuated signals detected by the instruments and analyzed quantitatively. The electromagnetic signal produced by the instrument may originate from mechanical energy such as sound waves (ultrasound - US), 'photon' radiation (X-ray-computed tomography - CT, dual-energy X-ray absorptiometry - DXA) or radio frequency waves (magnetic resonance imaging - MRI). The signals detected by the corresponding instruments are processed to measure, for example, tissue depths, areas, volumes or distributions of fat, muscle (water, protein) and partly bone or bone mineral. Among the above techniques, CT is the most accurate one followed by MRI and DXA, whereas US can be used for all sizes of farm animal species even under field conditions. CT, MRI and US can provide volume data, whereas only DXA delivers immediate whole-body composition results without (2D) image manipulation. A combination of simple US and more expensive CT, MRI or DXA might be applied for farm animal selection programs in a stepwise approach. PMID:25743562

  16. Method and apparatus for multiple-projection, dual-energy x-ray absorptiometry scanning

    NASA Technical Reports Server (NTRS)

    Charles, Jr., Harry K. (Inventor); Beck, Thomas J. (Inventor); Feldmesser, Howard S. (Inventor); Magee, Thomas C. (Inventor)

    2007-01-01

    Methods and apparatuses for advanced, multiple-projection, dual-energy X-ray absorptiometry scanning systems include combinations of a conical collimator; a high-resolution two-dimensional detector; a portable, power-capped, variable-exposure-time power supply; an exposure-time control element; calibration monitoring; a three-dimensional anti-scatter-grid; and a gantry-gantry base assembly that permits up to seven projection angles for overlapping beams. Such systems are capable of high precision bone structure measurements that can support three dimensional bone modeling and derivations of bone strength, risk of injury, and efficacy of countermeasures among other properties.

  17. Technical note: Prediction of chemical rib section composition by dual energy X-ray absorptiometry in Zebu beef cattle.

    PubMed

    Prados, L F; Zanetti, D; Amaral, P M; Mariz, L D S; Sathler, D F T; Filho, S C Valadares; Silva, F F; Silva, B C; Pacheco, M C; Alhadas, H M; Chizzotti, M L

    2016-06-01

    It is expensive and laborious to evaluate carcass composition in beef cattle. The objective of this study was to evaluate a method to predict the 9th to 11th rib section (rib) composition through empirical equations using dual energy X-ray absorptiometry (DXA). Dual energy X-ray absorptiometry is a validated method used to describe tissue composition in humans and other animals, but few studies have evaluated this technique in beef cattle, and especially in the Zebu genotype. A total of 116 rib were used to evaluate published prediction equations for rib composition and to develop new regression models using a cross-validation procedure. For the proposed models, 93 ribs were randomly selected to calculate the new regression equations, and 23 different ribs were randomly selected to validate the regressions. The rib from left carcasses were taken from Nellore and Nellore × Angus bulls from 3 different studies and scanned using DXA equipment (GE Healthcare, Madison, WI) in the Health Division at Universidade Federal de Viçosa (Viçosa, Brazil). The outputs of the DXA report were DXA lean (g), DXA fat free mass (g), DXA fat mass (g), and DXA bone mineral content (BMC; g). After being scanned, the rib were dissected, ground, and chemically analyzed for total ether extract (EE), CP, water, and ash content. The predictions of rib fat and protein from previous published equations were different ( < 0.01) from the observed composition. New equations were established through leave-one-out cross-validation using the REG procedure in SAS. The equations were as follows: lean (g) = 37.082 + 0.907× DXA lean ( = 0.95); fat free mass (g) = 103.224 + 0.869 × DXA fat free mass ( = 0.93); EE mass (g) = 122.404 + 1.119 × DXA fat mass ( = 0.86); and ash mass (g) = 18.722 + 1.016 × DXA BMC ( = 0.39). The equations were validated using Mayer's test, the concordance correlation coefficient, and the mean square error of prediction for decomposition. For both equations, Mayer's test

  18. Estimation of percentage body fat by dual-energy x-ray absorptiometry: evaluation by in vivo human elemental composition.

    PubMed

    Wang, ZiMian; Heymsfield, Steven B; Chen, Zhao; Zhu, Shankuan; Pierson, Richard N

    2010-05-01

    Dual-energy x-ray absorptiometry (DXA) is widely applied for estimating body fat. The percentage of body mass as fat (%fat) is predicted from a DXA-estimated R(ST) value defined as the ratio of soft tissue attenuation at two photon energies (e.g., 40 keV and 70 keV). Theoretically, the R(ST) concept depends on the mass of each major element in the human body. The DXA R(ST) values, however, have never been fully evaluated by measured human elemental composition. The present investigation evaluated the DXA R(ST) value by the total body mass of 11 major elements and the DXA %fat by the five-component (5C) model, respectively. Six elements (i.e. C, N, Na, P, Cl and Ca) were measured by in vivo neutron activation analysis, and potassium (i.e. K) by whole-body (40)K counting in 27 healthy adults. Models were developed for predicting the total body mass of four additional elements (i.e. H, O, Mg and S). The elemental content of soft tissue, after correction for bone mineral elements, was used to predict the R(ST) values. The DXA R(ST) values were strongly associated with the R(ST) values predicted from elemental content (r = 0.976, P < 0.001), although there was a tendency for the elemental-predicted R(ST) to systematically exceed the DXA-measured R(ST) (mean +/- SD, 1.389 +/- 0.024 versus 1.341 +/- 0.024). DXA-estimated %fat was strongly associated with 5C %fat (24.4 +/- 12.0% versus 24.9 +/- 11.1%, r = 0.983, P < 0.001). DXA R(ST) is evaluated by in vivo elemental composition, and the present study supports the underlying physical concept and accuracy of the DXA method for estimating %fat. PMID:20393230

  19. Estimation of percentage body fat by dual-energy x-ray absorptiometry: evaluation by in vivo human elemental composition

    NASA Astrophysics Data System (ADS)

    Wang, ZiMian; Heymsfield, Steven B.; Chen, Zhao; Zhu, Shankuan; Pierson, Richard N.

    2010-05-01

    Dual-energy x-ray absorptiometry (DXA) is widely applied for estimating body fat. The percentage of body mass as fat (%fat) is predicted from a DXA-estimated RST value defined as the ratio of soft tissue attenuation at two photon energies (e.g., 40 keV and 70 keV). Theoretically, the RST concept depends on the mass of each major element in the human body. The DXA RST values, however, have never been fully evaluated by measured human elemental composition. The present investigation evaluated the DXA RST value by the total body mass of 11 major elements and the DXA %fat by the five-component (5C) model, respectively. Six elements (i.e. C, N, Na, P, Cl and Ca) were measured by in vivo neutron activation analysis, and potassium (i.e. K) by whole-body 40K counting in 27 healthy adults. Models were developed for predicting the total body mass of four additional elements (i.e. H, O, Mg and S). The elemental content of soft tissue, after correction for bone mineral elements, was used to predict the RST values. The DXA RST values were strongly associated with the RST values predicted from elemental content (r = 0.976, P < 0.001), although there was a tendency for the elemental-predicted RST to systematically exceed the DXA-measured RST (mean ± SD, 1.389 ± 0.024 versus 1.341 ± 0.024). DXA-estimated %fat was strongly associated with 5C %fat (24.4 ± 12.0% versus 24.9 ± 11.1%, r = 0.983, P < 0.001). DXA RST is evaluated by in vivo elemental composition, and the present study supports the underlying physical concept and accuracy of the DXA method for estimating %fat.

  20. Estimation of percentage body fat by dual-energy x-ray absorptiometry: evaluation by in vivo human elemental composition

    PubMed Central

    Wang, ZiMian; Heymsfield, Steven B; Chen, Zhao; Zhu, Shankuan; Pierson, Richard N

    2010-01-01

    Dual-energy x-ray absorptiometry (DXA) is widely applied for estimating body fat. The percentage of body mass as fat (%fat) is predicted from a DXA-estimated RST value defined as the ratio of soft tissue attenuation at two photon energies (e.g., 40 keV and 70 keV). Theoretically, the RST concept depends on the mass of each major element in the human body. The DXA RST values, however, have never been fully evaluated by measured human elemental composition. The present investigation evaluated the DXA RST value by the total body mass of 11 major elements and the DXA %fat by the five-component (5C) model, respectively. Six elements (i.e. C, N, Na, P, Cl and Ca) were measured by in vivo neutron activation analysis, and potassium (i.e. K) by whole-body 40K counting in 27 healthy adults. Models were developed for predicting the total body mass of four additional elements (i.e. H, O, Mg and S). The elemental content of soft tissue, after correction for bone mineral elements, was used to predict the RST values. The DXA RST values were strongly associated with the RST values predicted from elemental content (r = 0.976, P < 0.001), although there was a tendency for the elemental-predicted RST to systematically exceed the DXA-measured RST (mean ± SD, 1.389 ± 0.024 versus 1.341 ± 0.024). DXA-estimated %fat was strongly associated with 5C %fat (24.4 ± 12.0% versus 24.9 ± 11.1%, r = 0.983, P < 0.001). DXA RST evaluated by in vivo elemental composition, and the present study supports the underlying physical concept and accuracy of the DXA method for estimating %fat. PMID:20393230

  1. The measurement of body segment inertial parameters using dual energy X-ray absorptiometry.

    PubMed

    Durkin, Jennifer L; Dowling, James J; Andrews, David M

    2002-12-01

    Accurate body segment parameter (BSP) information is required for dynamic analyses of motion and the current methods available for obtaining these BSPs have been criticized. The purpose of this study was to determine whether dual energy X-ray absorptiometry (DXA) could accurately measure the BSPs of scanned objects and thus be used as a tool for measuring the BSPs of human subjects. Whole body mass (WBM) of 11 males was measured from a DXA scan and the values were compared to criterion scale-measured values by calculating the mean percent error. Two objects (plastic cylinder, human cadaver leg) were also scanned and DXA measurements of mass, length, centre of mass location (CM) and moment of inertia about the centre of mass (I(CM)) were made using custom software. Criterion BSP measurements were then made and compared to DXA BSP values by calculating the percent error. Criterion I(CM) measurements of the two objects were made using a pendulum technique and a second criterion I(CM) calculation was made for the cylinder using a geometric formula. A mean percent error of -1.05% +/-1.32% was found for WBM measurements of the human subjects. Errors for the cylinder and cadaver leg were under 3.2% for all BSPs except for I(CM) when DXA was compared to the pendulum method (14.3% and 8.2% for cylinder and leg, respectively). The errors between DXA and the pendulum method were attributed to uncertainty in the pendulum technique (J. Biomech. 2002, in Review). I(CM) error of the cylinder when DXA was compared to the geometric calculation was 2.63%. This error, combined with the low errors for all other BSPs, indicated that DXA can be used as a simple and accurate means of obtaining direct BSP information on living humans. PMID:12445610

  2. Photon absorptiometry

    SciTech Connect

    Velchik, M.G.

    1987-01-01

    Recently, there has been a renewed interest in the detection and treatment of osteoporosis. This paper is a review of the merits and limitations of the various noninvasive modalities currently available for the measurement of bone mineral density with special emphasis placed upon the nuclear medicine techniques of single-photon and dual-photon absorptiometry. The clinicians should come away with an understanding of the relative advantages and disadvantages of photon absorptiometry and its optimal clinical application. 49 references.

  3. Generation of 3D shape, density, cortical thickness and finite element mesh of proximal femur from a DXA image.

    PubMed

    Väänänen, Sami P; Grassi, Lorenzo; Flivik, Gunnar; Jurvelin, Jukka S; Isaksson, Hanna

    2015-08-01

    Areal bone mineral density (aBMD), as measured by dual-energy X-ray absorptiometry (DXA), predicts hip fracture risk only moderately. Simulation of bone mechanics based on DXA imaging of the proximal femur, may help to improve the prediction accuracy. Therefore, we collected three (1-3) image sets, including CT images and DXA images of 34 proximal cadaver femurs (set 1, including 30 males, 4 females), 35 clinical patient CT images of the hip (set 2, including 27 males, 8 females) and both CT and DXA images of clinical patients (set 3, including 12 female patients). All CT images were segmented manually and landmarks were placed on both femurs and pelvises. Two separate statistical appearance models (SAMs) were built using the CT images of the femurs and pelvises in sets 1 and 2, respectively. The 3D shape of the femur was reconstructed from the DXA image by matching the SAMs with the DXA images. The orientation and modes of variation of the SAMs were adjusted to minimize the sum of the absolute differences between the projection of the SAMs and a DXA image. The mesh quality and the location of the SAMs with respect to the manually placed control points on the DXA image were used as additional constraints. Then, finite element (FE) models were built from the reconstructed shapes. Mean point-to-surface distance between the reconstructed shape and CT image was 1.0 mm for cadaver femurs in set 1 (leave-one-out test) and 1.4 mm for clinical subjects in set 3. The reconstructed volumetric BMD showed a mean absolute difference of 140 and 185 mg/cm(3) for set 1 and set 3 respectively. The generation of the SAM and the limitation of using only one 2D image were found to be the most significant sources of errors in the shape reconstruction. The noise in the DXA images had only small effect on the accuracy of the shape reconstruction. DXA-based FE simulation was able to explain 85% of the CT-predicted strength of the femur in stance loading. The present method can be used to

  4. Reproducibility and accuracy of body composition assessments in mice by dual energy x-ray absorptiometry and time domain nuclear magnetic resonance

    PubMed Central

    Halldorsdottir, Solveig; Carmody, Jill; Boozer, Carol N.; Leduc, Charles A.; Leibel, Rudolph L.

    2011-01-01

    Objective To assess the accuracy and reproducibility of dual-energy absorptiometry (DXA; PIXImus™) and time domain nuclear magnetic resonance (TD-NMR; Bruker Optics) for the measurement of body composition of lean and obese mice. Subjects and measurements Thirty lean and obese mice (body weight range 19–67 g) were studied. Coefficients of variation for repeated (x 4) DXA and NMR scans of mice were calculated to assess reproducibility. Accuracy was assessed by comparing DXA and NMR results of ten mice to chemical carcass analyses. Accuracy of the respective techniques was also assessed by comparing DXA and NMR results obtained with ground meat samples to chemical analyses. Repeated scans of 10–25 gram samples were performed to test the sensitivity of the DXA and NMR methods to variation in sample mass. Results In mice, DXA and NMR reproducibility measures were similar for fat tissue mass (FTM) (DXA coefficient of variation [CV]=2.3%; and NMR CV=2.8%) (P=0.47), while reproducibility of lean tissue mass (LTM) estimates were better for DXA (1.0%) than NMR (2.2%) (

    DXA overestimated (vs chemical composition) LTM (+1.7 ± 1.3 g [SD], ~ 8%, P <0.001) as well as FTM (+2.0 ± 1.2 g, ~ 46%, P <0.001). NMR estimated LTM and FTM virtually identical to chemical composition analysis (LTM: −0.05 ± 0.5 g, ~0.2%, P =0.79) (FTM: +0.02 ± 0.7 g, ~15%, P =0.93). DXA and NMR-determined LTM and FTM measurements were highly correlated with the corresponding chemical analyses (r2=0.92 and r2=0.99 for DXA LTM and FTM, respectively; r2=0.99 and r2=0.99 for NMR LTM and FTM, respectively.) Sample mass did not affect accuracy in assessing chemical composition of small ground meat samples by either DXA or NMR. Conclusion DXA and NMR provide comparable levels of reproducibility in measurements of body composition lean and obese mice. While DXA and NMR measures are highly correlated with chemical analysis measures, DXA consistently overestimates LTM

  5. Longitudinal DXA Studies: Minimum scanning interval for pediatric assessment of body fat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The increased prevalence of obesity in the United States, has led to the increased use of dual-energy X-ray absorptiometry (DXA) for assessment of body fat mass (TBF) in pediatric populations. We examined DXA precision, in order to determine suitable scanning intervals for the measurement of change...

  6. Clinical practice guidelines proposed by the Hellenic Foundation of Osteoporosis for the management of osteoporosis based on DXA results.

    PubMed

    Baltas, C S; Balanika, A P; Raptou, P D; Tournis, S; Lyritis, G P

    2005-01-01

    In recent years guidelines for the testing and treatment of osteoporotic patients have been published by recognised organisations, including the World Health Organisation (WHO), the National Osteoporosis Foundation (NOF) and the International Osteoporosis Foundation (IOF). Dual Energy X-ray Absorptiometry (DXA) has been considered the technique of choice because of its excellent precision and ability to predict osteoporotic fractures. Last December, based on the Appraisal of the Guidelines for Research and Evaluation (AGREE), the Hellenic Foundation of Osteoporosis, in collaboration with other scientific societies, provided guidelines for the use of DXA for the diagnosis, monitoring and treatment of osteoporosis and Quality Assurance (QA) of these systems. According to these guidelines, the adequacy of the present number of DXA units in Greece was assessed. There are 367 DXA units in Greece, and almost 50% are located in the capital city, Athens, where 34.1% of the population lives. The distribution of DXA devices per resident in the Greek provinces (except Attica) is between 4.2 units/100,000 heads (Ionian Islands) and 1.6 units/100,000 heads (Sterea Hellas). These guidelines have resulted in a suggestive yearly repeat of the measurements, to ensure the precision of the method, but mainly for reasons of compliance. Finally, these guidelines are viewed as a work in progress and will be updated periodically in response to advances in this field. PMID:16340144

  7. Comparison of Anthropometry to Dual Energy X-Ray Absorptiometry: A New Prediction Equation for Women

    ERIC Educational Resources Information Center

    Ball, Stephen; Swan, Pamela D.; DeSimone, Rosemarie

    2004-01-01

    The purpose of this study was to assess the accuracy of three recommended anthropometric equations for women and then develop an updated prediction equation using dual energy x-ray absorptiometry (DXA). The percentage of body fat (%BF) by anthropometry was significantly correlated (r = .896-. 929; p [is less than] .01) with DXA, but each equation…

  8. Body composition in taller individuals using DXA: A validation study for athletic and non-athletic populations.

    PubMed

    Santos, Diana A; Gobbo, Luís A; Matias, Catarina N; Petroski, Edio L; Gonçalves, Ezequiel M; Cyrino, Edilson S; Minderico, Claudia S; Sardinha, Luís B; Silva, Analiza M

    2013-01-01

    Dual energy X-ray absorptiometry (DXA) cannot be used to evaluate participants taller than the scan area. We aimed to analyse the accuracy of bone mineral content, fat mass, and lean mass assessed with DXA whole-body scan and from the sum of two scans (head and trunk plus limbs). Participants were 31 athletes (13 males and 18 females) and 65 non-athletes (34 males and 31 females), that fit within the DXA scan area. Three scans were performed using a Hologic Explorer-W fan-beam densitometer: a whole-body scan used as the reference; a head scan; and a trunk and limbs scan. The sum of the head scan and the trunk and limbs scan was used as the alternative procedure. Multiple regression and agreement analysis were performed. Non-significant differences between methods were observed for fat mass (0.06 kg) and lean mass (-0.07 kg) while bone mineral content from the alternative procedure differed from the reference scan (0.009 kg). The alternative procedure explained > 99% of the variance in the reference scan and low limits of agreement were observed. Precision analysis indicated low pure errors and the higher coefficients of variation were found for fat mass (whole-body: 3.70%; subtotal: 4.05%). The method proposed is a valid and simple solution to be used in individuals taller than the DXA scan area, including athletes engaged in sports recognised for including very tall competitors. PMID:23092580

  9. Radiographic morphometry and densitometry predict strength of cadaveric proximal humeri more reliably than age and DXA scan density.

    PubMed

    Skedros, John G; Knight, Alex N; Pitts, Todd C; O'Rourke, Peter J; Burkhead, Wayne Z

    2016-02-01

    Methods are needed for identifying poorer quality cadaver proximal humeri to ensure that they are not disproportionately segregated into experimental groups for fracture studies. We hypothesized that measurements made from radiographs of cadaveric proximal humeri are stronger predictors of fracture strength than chronological age or bone density values derived from dual-energy x-ray absorptiometry (DXA) scans. Thirty-three proximal humeri (range: 39-78 years) were analyzed for: (1) bone mineral density (BMD, g/cm(2)) using DXA, (2) bulk density (g/cm(3)) using DXA and volume displacement, (3) regional bone density in millimeters of aluminum (mmAl) using radiographs, and (4) regional mean (medial+lateral) cortical thickness and cortical index (CI) using radiographs. The bones were then fractured simulating a fall. Strongest correlations with ultimate fracture load (UFL) were: mean cortical thickness at two diaphyseal locations (r = 0.71; p < 0.001), and mean mmAl in the humeral head (r = 0.70; p < 0.001). Weaker correlations were found between UFL and DXA-BMD (r = 0.60), bulk density (r = 0.43), CI (r = 0.61), and age (r = -0.65) (p values <0.01). Analyses between UFL and the product of any two characteristics showed six combinations with r-values >0.80, but none included DXA-derived density, CI, or age. Radiographic morphometric and densitometric measurements from radiographs are therefore stronger predictors of UFL than age, CI, or DXA-derived density measurements. PMID:26218571

  10. BMI and an Anthropometry-Based Estimate of Fat Mass Percentage Are Both Valid Discriminators of Cardiometabolic Risk: A Comparison with DXA and Bioimpedance

    PubMed Central

    Völgyi, Eszter; Savonen, Kai; Tylavsky, Frances A.; Alén, Markku; Cheng, Sulin

    2013-01-01

    Objective. To determine whether categories of obesity based on BMI and an anthropometry-based estimate of fat mass percentage (FM% equation) have similar discriminative ability for markers of cardiometabolic risk as measurements of FM% by dual-energy X-ray absorptiometry (DXA) or bioimpedance analysis (BIA). Design and Methods. A study of 40–79-year-old male (n = 205) and female (n = 388) Finns. Weight, height, blood pressure, triacylglycerols, HDL cholesterol, and fasting blood glucose were measured. Body composition was assessed by DXA and BIA and a FM%-equation. Results. For grade 1 hypertension, dyslipidaemia, and impaired fasting glucose >6.1 mmol/L, the categories of obesity as defined by BMI and the FM% equation had 1.9% to 3.7% (P < 0.01) higher discriminative power compared to DXA. For grade 2 hypertension the FM% equation discriminated 1.2% (P = 0.05) lower than DXA and 2.8% (P < 0.01) lower than BIA. Receiver operation characteristics confirmed BIA as best predictor of grade 2 hypertension and the FM% equation as best predictor of grade 1 hypertension. All other differences in area under curve were small (≤0.04) and 95% confidence intervals included 0. Conclusions. Both BMI and FM% equations may predict cardiometabolic risk with similar discriminative ability as FM% measured by DXA or BIA. PMID:24455216

  11. Body composition in young female eating-disorder patients with severe weight loss and controls: evidence from the four-component model and evaluation of DXA

    PubMed Central

    Wells, J C K; Haroun, D; Williams, J E; Nicholls, D; Darch, T; Eaton, S; Fewtrell, M S

    2015-01-01

    Background/Objectives: Whether fat-free mass (FFM) and its components are depleted in eating-disorder (ED) patients is uncertain. Dual energy X-ray absorptiometry (DXA) is widely used to assess body composition in pediatric ED patients; however, its accuracy in underweight populations remains unknown. We aimed (1) to assess body composition of young females with ED involving substantial weight loss, relative to healthy controls using the four-component (4C) model, and (2) to explore the validity of DXA body composition assessment in ED patients. Subjects/Methods: Body composition of 13 females with ED and 117 controls, aged 10–18 years, was investigated using the 4C model. Accuracy of DXA for estimation of FFM and fat mass (FM) was tested using the approach of Bland and Altman. Results: Adjusting for age, height and pubertal stage, ED patients had significantly lower whole-body FM, FFM, protein mass (PM) and mineral mass (MM) compared with controls. Trunk and limb FM and limb lean soft tissue were significantly lower in ED patients. However, no significant difference in the hydration of FFM was detected. Compared with the 4C model, DXA overestimated FM by 5±36% and underestimated FFM by 1±9% in ED patients. Conclusion: Our study confirms that ED patients are depleted not only in FM but also in FFM, PM and MM. DXA has limitations for estimating body composition in individual young female ED patients. PMID:26173868

  12. Guidelines for Dual Energy X-Ray Absorptiometry Analysis of Trabecular Bone-Rich Regions in Mice: Improved Precision, Accuracy, and Sensitivity for Assessing Longitudinal Bone Changes.

    PubMed

    Shi, Jiayu; Lee, Soonchul; Uyeda, Michael; Tanjaya, Justine; Kim, Jong Kil; Pan, Hsin Chuan; Reese, Patricia; Stodieck, Louis; Lin, Andy; Ting, Kang; Kwak, Jin Hee; Soo, Chia

    2016-05-01

    Trabecular bone is frequently studied in osteoporosis research because changes in trabecular bone are the most common cause of osteoporotic fractures. Dual energy X-ray absorptiometry (DXA) analysis specific to trabecular bone-rich regions is crucial to longitudinal osteoporosis research. The purpose of this study is to define a novel method for accurately analyzing trabecular bone-rich regions in mice via DXA. This method will be utilized to analyze scans obtained from the International Space Station in an upcoming study of microgravity-induced bone loss. Thirty 12-week-old BALB/c mice were studied. The novel method was developed by preanalyzing trabecular bone-rich sites in the distal femur, proximal tibia, and lumbar vertebrae via high-resolution X-ray imaging followed by DXA and micro-computed tomography (micro-CT) analyses. The key DXA steps described by the novel method were (1) proper mouse positioning, (2) region of interest (ROI) sizing, and (3) ROI positioning. The precision of the new method was assessed by reliability tests and a 14-week longitudinal study. The bone mineral content (BMC) data from DXA was then compared to the BMC data from micro-CT to assess accuracy. Bone mineral density (BMD) intra-class correlation coefficients of the new method ranging from 0.743 to 0.945 and Levene's test showing that there was significantly lower variances of data generated by new method both verified its consistency. By new method, a Bland-Altman plot displayed good agreement between DXA BMC and micro-CT BMC for all sites and they were strongly correlated at the distal femur and proximal tibia (r=0.846, p<0.01; r=0.879, p<0.01, respectively). The results suggest that the novel method for site-specific analysis of trabecular bone-rich regions in mice via DXA yields more precise, accurate, and repeatable BMD measurements than the conventional method. PMID:26956416

  13. Pediatric DXA: clinical applications

    PubMed Central

    Sparke, Paul; Henwood, Maria J.

    2007-01-01

    Normal bone mineral accrual requires adequate dietary intake of calcium, vitamin D and other nutrients; hepatic and renal activation of vitamin D; normal hormone levels (thyroid, parathyroid, reproductive and growth hormones); and neuromuscular functioning with sufficient stress upon the skeleton to induce bone deposition. The presence of genetic or acquired diseases and the therapies that are used to treat them can also impact bone health. Since the introduction of clinical DXA in pediatrics in the early 1990s, there has been considerable investigation into the causes of low bone mineral density (BMD) in children. Pediatricians have also become aware of the role adequate bone mass accrual in childhood has in preventing osteoporotic fractures in late adulthood. Additionally, the availability of medications to improve BMD has increased with the development of bisphosphonates. These factors have led to the increased utilization of DXA in pediatrics. This review summarizes much of the previous research regarding BMD in children and is meant to assist radiologists and clinicians with DXA utilization and interpretation. PMID:17431606

  14. Dual-energy X-ray absorptiometry and body composition.

    PubMed

    Laskey, M A

    1996-01-01

    This review describes the advantages and limitations of dual-energy absorptiometry (DXA), a technique that is widely used clinically to assess a patient's risk of osteoporosis and to monitor the effects of therapy. DXA is also increasingly used to measure body composition in terms of fat and fat-free mass. There are three commercial manufacturers of DXA instruments: Lunar, Hologic, and Norland. All systems generate X-rays at two different energies and make use of the differential attenuation of the X-ray beam at these two energies to calculate the bone mineral content and soft tissue composition in the scanned region. Most DXA instruments measure bone mineral in the clinically important sites of the spine, hip, and forearm. More specialized systems also perform whole-body scans and can be used to determine the bone and soft tissue composition of the whole body and subregions such as arms, legs, and trunk. The effective dose incurred during DXA scanning is very small, and, consequently, DXA is a simple and safe technique that can be used for children and the old and frail. Precision of all DXA measurements is excellent but varies with the region under investigation. Precision is best for young healthy subjects (coefficient of variation is about 1% for the spine and whole body bone measurements) but is less good for osteoporotic and obese subjects. The accuracy of DXA measurements, however, can be problematic. Marked systematic differences in bone and soft tissue values are found between the three commercial systems due to differences in calibration, bone edge detection, and other factors. In addition, differences in reference data provided by each manufacturer can lead to an individual appearing normal on one machine but at risk of osteoporosis on another. At present, DXA cannot be regarded as a "gold standard" for body composition. However, the continuing development of DXA and the introduction of new software is greatly improving the performance of this

  15. Measurement of Percentage of Body Fat in 411 Children and Adolescents: A Comparison of Dual-Energy X-Ray Absorptiometry With a Four-Compartment Model

    PubMed Central

    Sopher, Aviva B.; Thornton, John C.; Wang, Jack; Pierson, Richard N.; Heymsfield, Steven B.; Horlick, Mary

    2015-01-01

    Objective Pediatricians are encountering body composition information more frequently, with percentage of body fat (%BF) measurement receiving particular attention as a result of the obesity epidemic. One confounding issue is that different methods may yield different %BF results in the same person. The objective of this study was to compare dual-energy X-ray absorptiometry (DXA) with the criterion 4-compartment model (4-CM) for measurement of %BF in a large pediatric cohort and to assist pediatricians in appropriate interpretation of body composition information by recognizing differences between techniques. Methods Height, weight, anthropometrics, body density by underwater weighing, total body water by deuterium dilution, and bone mineral content and %BF by DXA (Lunar DPX/DPX-L) were measured in 411 healthy subjects, aged 6 to 18 years. Values for %BF by 4-CM and DXA were compared using regression analysis. Results The mean ± standard deviation values for %BF by DXA (22.73% ± 11.23%) and by 4-CM (21.72% ± 9.42%) were different, but there was a strong relationship between the 2 methods (R2 = 0.85). DXA underestimated %BF in subjects with lower %BF and overestimated it in those with higher %BF. The relationship between the 2 methods was not affected by gender, age, ethnicity, pubertal stage, height, weight, or body mass index. The standard error of the estimate was 3.66%. Conclusion This analysis demonstrates a predictable relationship between DXA and 4-CM for %BF measurement. Because of its ease of use, consistent relationship with 4-CM, and availability, we propose that DXA has the capacity for clinical application including prediction of metabolic abnormalities associated with excess %BF in pediatrics. PMID:15121943

  16. Comparison of visceral fat mass measurement by dual-X-ray absorptiometry and magnetic resonance imaging in a multiethnic cohort: the Dallas Heart Study

    PubMed Central

    Neeland, I J; Grundy, S M; Li, X; Adams-Huet, B; Vega, G L

    2016-01-01

    Background/Objectives: Visceral adipose tissue (VAT) mass, a risk factor for cardiometabolic complications of obesity, is usually measured by magnetic resonance imaging (MRI) but this method is not practical in a clinical setting. In contrast, measurement of VAT by dual-x-ray absorptiometry (DXA) appears to circumvent the limitations of MRI. In this study, we compared measurements of VAT mass by MRI and DXA in the large, multiethnic cohort of the Dallas Heart Study (DHS). Subjects/Methods: About 2689 DHS participants underwent paired measurement of VAT by MRI and DXA. Sex-stratified analyses were performed to evaluate the correlation and agreement between DXA and MRI. Model validation was performed using bootstrapping and inter-reader variability was assessed. Results: Mean age of the cohort was 44 years, with 55% female, 48% Black and 75% overweight/obese participants. Regression analysis showed a linear relationship between DXA and MRI with R2=0.82 (95% confidence interval (CI) 0.81–0.84) for females and R2=0.86 (95% CI 0.85–0.88) for males. Mean difference between methods was 0.01 kg for females and 0.09 kg for males. Bland–Altman analysis showed that DXA tended to modestly underestimate VAT compared with MRI at lower VAT levels and overestimate it compared with MRI at higher VAT levels. Results were consistent in analyses stratified by race, body mass index status, waist girth and body fat. Inter-individual reader correlation among 50 randomly selected scans was excellent (inter-class correlation coefficient=0.997). Conclusions: VAT mass quantification by DXA was both accurate and valid among a large, multiethnic cohort within a wide range of body fatness. Further studies including repeat assessments over time will help determine its long-term applicability. PMID:27428873

  17. Utilization of DXA Bone Mineral Densitometry in Ontario

    PubMed Central

    2006-01-01

    Executive Summary Issue Systematic reviews and analyses of administrative data were performed to determine the appropriate use of bone mineral density (BMD) assessments using dual energy x-ray absorptiometry (DXA), and the associated trends in wrist and hip fractures in Ontario. Background Dual Energy X-ray Absorptiometry Bone Mineral Density Assessment Dual energy x-ray absorptiometry bone densitometers measure bone density based on differential absorption of 2 x-ray beams by bone and soft tissues. It is the gold standard for detecting and diagnosing osteoporosis, a systemic disease characterized by low bone density and altered bone structure, resulting in low bone strength and increased risk of fractures. The test is fast (approximately 10 minutes) and accurate (exceeds 90% at the hip), with low radiation (1/3 to 1/5 of that from a chest x-ray). DXA densitometers are licensed as Class 3 medical devices in Canada. The World Health Organization has established criteria for osteoporosis and osteopenia based on DXA BMD measurements: osteoporosis is defined as a BMD that is >2.5 standard deviations below the mean BMD for normal young adults (i.e. T-score <–2.5), while osteopenia is defined as BMD that is more than 1 standard deviation but less than 2.5 standard deviation below the mean for normal young adults (i.e. T-score< –1 & ≥–2.5). DXA densitometry is presently an insured health service in Ontario. Clinical Need   Burden of Disease The Canadian Multicenter Osteoporosis Study (CaMos) found that 16% of Canadian women and 6.6% of Canadian men have osteoporosis based on the WHO criteria, with prevalence increasing with age. Osteopenia was found in 49.6% of Canadian women and 39% of Canadian men. In Ontario, it is estimated that nearly 530,000 Ontarians have some degrees of osteoporosis. Osteoporosis-related fragility fractures occur most often in the wrist, femur and pelvis. These fractures, particularly those in the hip, are associated with increased

  18. Does Visceral Fat Estimated by Dual-Energy X-ray Absorptiometry Independently Predict Cardiometabolic Risks in Adults?

    PubMed Central

    Sasai, Hiroyuki; Brychta, Robert J.; Wood, Rachel P.; Rothney, Megan P.; Zhao, Xiongce; Skarulis, Monica C.; Chen, Kong Y.

    2015-01-01

    Background: Abdominal visceral fat, typically measured by computer tomography (CT) or magnetic resonance imaging (MRI), has been shown to correlate with cardiometabolic risks. The purpose of this study was to examine whether a newly developed and validated visceral fat measurement from dual-energy X-ray absorptiometry (DXA) provides added predictive value to the cross-sectional differences of cardiometabolic parameters beyond the traditional anthropometric and DXA adiposity parameters. Method: A heterogeneous cohort of 194 adults (81 males and 113 females) with a BMI of 19 to 54 kg/m2 participated in this cross-sectional study. Body composition was measured with a DXA densitometer. Visceral fat was then computed with a proprietary algorithm. Insulin sensitivity index (SI, measured by intravenous glucose tolerance test), blood pressures, and lipid profiles, and peak oxygen uptake were also measured as cardiometabolic risk parameters. Results: DXA-estimated visceral fat mass was associated with HDL cholesterol (regression coefficient [β] = −5.15, P < .01, adjusted R2 = .21), triglyceride (β = 26.01, P < .01, adjusted R2 = .14), and peak oxygen uptake (β = −3.15, P < .01, adjusted R2 = .57) after adjusting for age, gender, and ethnicity. A subanalysis stratifying gender-specific BMI tertiles showed visceral fat, together with ethnicity, was independently associated with SI in overweight men and moderately obese women (second tertile). Conclusions: Without requiring additional CT or MRI-based measurements, visceral fat detected by DXA might offer certain advantages over the traditional DXA adiposity parameters as means of assessing cardiometabolic risks. PMID:25802470

  19. Solid anthropomorphic infant whole body DXA phantom: Design, evaluation, and multisite testing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dual energy X-ray absorptiometry (DXA) requires phantoms for quality control and cross-calibration. No commercially available phantoms are designed specifically for infant whole-body scanning. We fabricated a phantom closely matching a 7-kg human infant in body habitus using PVC, nylon-mix, and poly...

  20. Generalized equations for estimating DXA percent fat of diverse young women and men: The Tiger Study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Popular generalized equations for estimating percent body fat (BF%) developed with cross-sectional data are biased when applied to racially/ethnically diverse populations. We developed accurate anthropometric models to estimate dual-energy x-ray absorptiometry BF% (DXA-BF%) that can be generalized t...

  1. Total body carbon and oxygen masses: evaluation of dual-energy x-ray absorptiometry estimation by in vivo neutron activation analysis.

    PubMed

    Wang, Zimian; Pierson, Richard N

    2010-10-01

    Oxygen and carbon are the first and second abundant elements, respectively, in the human body by mass. Although many physiological and pathological processes are accompanied with alteration of total body oxygen (TBO) and carbon (TBC) masses, in vivo measurements of the two elements are limited. Up to now, almost all available information of TBC and TBO is based on in vivo neutron activation (IVNA) analysis which is very expensive and involves moderate radiation exposure. The aim of the present study was to develop and evaluate an alternative strategy for TBC and TBO estimation. Mechanistic models were derived for predicting TBC and TBO masses from dual-energy x-ray absorptiometry (DXA) and total body water (TBW). Twenty-eight adult subjects were studied. IVNA-measured TBC and TBO masses were used as the criterion. TBC masses predicted by DXA-alone and by DXA-TBW models were 20.8 ± 7.1 kg and 20.6 ± 6.8 kg, respectively, close to the IVNA-measured value (19.5 ± 6.3 kg). There were strong correlations (both with r > 0.95, P < 0.001) between the predicted and measured TBC masses. TBO masses predicted by DXA-alone and by DXA-TBW models were 46.0 ± 9.8 kg and 46.5 ± 9.9 kg, respectively, close to the IVNA-measured value (48.0 ± 10.4 kg). Correlations (both with r > 0.97, P < 0.001) were strong between the predicted and measured TBO masses. Bland-Altman analysis validated the applicability of DXA-based models to predict TBC and TBO masses. As both DXA and TBW dilutions are widely available, low-risk, low-cost techniques, the present study provides a safe and practical method for estimating elemental composition in vivo. PMID:20858915

  2. Total body carbon and oxygen masses: evaluation of dual-energy x-ray absorptiometry estimation by in vivo neutron activation analysis

    NASA Astrophysics Data System (ADS)

    Wang, ZiMian; Pierson, Richard N., Jr.

    2010-10-01

    Oxygen and carbon are the first and second abundant elements, respectively, in the human body by mass. Although many physiological and pathological processes are accompanied with alteration of total body oxygen (TBO) and carbon (TBC) masses, in vivo measurements of the two elements are limited. Up to now, almost all available information of TBC and TBO is based on in vivo neutron activation (IVNA) analysis which is very expensive and involves moderate radiation exposure. The aim of the present study was to develop and evaluate an alternative strategy for TBC and TBO estimation. Mechanistic models were derived for predicting TBC and TBO masses from dual-energy x-ray absorptiometry (DXA) and total body water (TBW). Twenty-eight adult subjects were studied. IVNA-measured TBC and TBO masses were used as the criterion. TBC masses predicted by DXA-alone and by DXA-TBW models were 20.8 ± 7.1 kg and 20.6 ± 6.8 kg, respectively, close to the IVNA-measured value (19.5 ± 6.3 kg). There were strong correlations (both with r > 0.95, P < 0.001) between the predicted and measured TBC masses. TBO masses predicted by DXA-alone and by DXA-TBW models were 46.0 ± 9.8 kg and 46.5 ± 9.9 kg, respectively, close to the IVNA-measured value (48.0 ± 10.4 kg). Correlations (both with r > 0.97, P < 0.001) were strong between the predicted and measured TBO masses. Bland-Altman analysis validated the applicability of DXA-based models to predict TBC and TBO masses. As both DXA and TBW dilutions are widely available, low-risk, low-cost techniques, the present study provides a safe and practical method for estimating elemental composition in vivo.

  3. DXA Utilization Between 2006 and 2012 in Commercially Insured Younger Postmenopausal Women.

    PubMed

    Overman, Robert A; Farley, Joel F; Curtis, Jeffrey R; Zhang, Jie; Gourlay, Margaret L; Deal, Chad L

    2015-01-01

    Reimbursement for dual-energy X-ray absorptiometry (DXA) scans in the outpatient setting has declined significantly since 2006. Research through 2011 has suggested reimbursement reductions for DXA scans have corresponded with an overall decreased utilization of DXA. This study updates utilization estimates for DXAs through 2012 in patients with commercial insurance and compares DXA rates before and after reimbursement changes. We evaluated DXA utilization for women aged 50-64 yr from Marketscan Commercial Claims and Encounter database between January 2006 and December 2012 based on CPT codes. We estimated utilization rates per 1000 person years (PY). We also used segmented regression analysis of monthly rates to evaluate the change in utilization rates after a proposed reimbursement reduction in July 2009. In women aged 50-64 yr, 451,656 DXAs were performed in 2006, a rate of 144 DXAs per 1000 PY. This rate increased to 149 DXAs per 1000 PY in 2009 before decreasing to 110 DXAs per 1000 PY or 667,982 scans in 2012. DXA utilization increased by 2.24 per 1000 PY until July 2009 then declined by 12.98 DXAs per 1000 persons, resulting in 37.5 DXAs per PY fewer performed in 2012 compared with 2006. Since July 2009 a significant decline in DXA utilization occurred in a younger postmenopausal commercially insured population. This decline corresponds with a time period of reductions in Medicare DXA reimbursement. PMID:25700662

  4. Periprosthetic DXA after total hip arthroplasty with short vs. ultra-short custom-made femoral stems

    PubMed Central

    Santori, Francesco S; Pavan, Laura; Learmonth, Ian D; Passariello, Roberto

    2009-01-01

    Background and purpose Dual-energy X-ray absorptiometry (DXA) analysis of the 7 periprosthetic Gruen zones is the most commonly used protocol to evaluate bone remodeling after the implantation of conventional femoral stems. We assessed the value of DXA after cementless primary total hip arthroplasty (THA) by comparing the effect of progressive shortening of the stem of two femoral implants on periprosthetic bone remodeling using a specifically developed protocol of analysis with 5 periprosthetic regions of interest (ROIs). Patients and methods Bone mineral density (BMD) was evaluated in 37 patients in the plateau stage, 3 years after THA. Two femoral implants featuring conceptually new designs and surgical technique were tested: types 1 and 2, characterized by extremely short stem and virtual absence of distal stem, respectively. Results We found that progressive shortening of the femoral stem produces more proximal loading, which effectively preserves metaphyseal bone stock and increases periprosthetic BMD in the medial ROIs over time. In the type 2 group, higher absolute BMD values were observed in medial ROIs 4 and 5. No differences were found in ROIs 1, 2, and 3. Interpretation This study shows the flexibility of DXA in adapting the protocol of periprosthetic analysis to the specific requirements of new implant designs, and it shows its high sensitivity in evaluation of the biological response of bone to changes in implant shape. PMID:19562565

  5. The accuracy and precision of DXA for assessing body composition in team sport athletes.

    PubMed

    Bilsborough, Johann Christopher; Greenway, Kate; Opar, David; Livingstone, Steuart; Cordy, Justin; Coutts, Aaron James

    2014-01-01

    This study determined the precision of pencil and fan beam dual-energy X-ray absorptiometry (DXA) devices for assessing body composition in professional Australian Football players. Thirty-six professional Australian Football players, in two groups (fan DXA, N = 22; pencil DXA, N = 25), underwent two consecutive DXA scans. A whole body phantom with known values for fat mass, bone mineral content and fat-free soft tissue mass was also used to validate each DXA device. Additionally, the criterion phantom was scanned 20 times by each DXA to assess reliability. Test-retest reliability of DXA anthropometric measures were derived from repeated fan and pencil DXA scans. Fat-free soft tissue mass and bone mineral content from both DXA units showed strong correlations with, and trivial differences to, the criterion phantom values. Fat mass from both DXA showed moderate correlations with criterion measures (pencil: r = 0.64; fan: r = 0.67) and moderate differences with the criterion value. The limits of agreement were similar for both fan beam DXA and pencil beam DXA (fan: fat-free soft tissue mass = -1650 ± 179 g, fat mass = -357 ± 316 g, bone mineral content = 289 ± 122 g; pencil: fat-free soft tissue mass = -1701 ± 257 g, fat mass = -359 ± 326 g, bone mineral content = 177 ± 117 g). DXA also showed excellent precision for bone mineral content (coefficient of variation (%CV) fan = 0.6%; pencil = 1.5%) and fat-free soft tissue mass (%CV fan = 0.3%; pencil = 0.5%) and acceptable reliability for fat measures (%CV fan: fat mass = 2.5%, percent body fat = 2.5%; pencil: fat mass = 5.9%, percent body fat = 5.7%). Both DXA provide precise measures of fat-free soft tissue mass and bone mineral content in lean Australian Football players. DXA-derived fat-free soft tissue mass and bone mineral content are suitable for assessing body composition in lean team sport athletes. PMID:24914773

  6. DXA, bioelectrical impedance, ultrasonography and biometry for the estimation of fat and lean mass in cats during weight loss

    PubMed Central

    2012-01-01

    Background Few equations have been developed in veterinary medicine compared to human medicine to predict body composition. The present study was done to evaluate the influence of weight loss on biometry (BIO), bioimpedance analysis (BIA) and ultrasonography (US) in cats, proposing equations to estimate fat (FM) and lean (LM) body mass, as compared to dual energy x-ray absorptiometry (DXA) as the referenced method. For this were used 16 gonadectomized obese cats (8 males and 8 females) in a weight loss program. DXA, BIO, BIA and US were performed in the obese state (T0; obese animals), after 10% of weight loss (T1) and after 20% of weight loss (T2). Stepwise regression was used to analyze the relationship between the dependent variables (FM, LM) determined by DXA and the independent variables obtained by BIO, BIA and US. The better models chosen were evaluated by a simple regression analysis and means predicted vs. determined by DXA were compared to verify the accuracy of the equations. Results The independent variables determined by BIO, BIA and US that best correlated (p < 0.005) with the dependent variables (FM and LM) were BW (body weight), TC (thoracic circumference), PC (pelvic circumference), R (resistance) and SFLT (subcutaneous fat layer thickness). Using Mallows’Cp statistics, p value and r2, 19 equations were selected (12 for FM, 7 for LM); however, only 7 equations accurately predicted FM and one LM of cats. Conclusions The equations with two variables are better to use because they are effective and will be an alternative method to estimate body composition in the clinical routine. For estimated lean mass the equations using body weight associated with biometrics measures can be proposed. For estimated fat mass the equations using body weight associated with bioimpedance analysis can be proposed. PMID:22781317

  7. Dual-photon absorptiometry: Comparison of bone mineral and soft tissue mass measurements in vivo with established methods

    SciTech Connect

    Heymsfield, S.B.; Wang, J.; Heshka, S.; Kehayias, J.J.; Pierson, R.N.

    1989-06-01

    This study extended initial observations that indicated the potential of dual-photon absorptiometry (DPA) to measure total-body bone mineral (TBBM) and fat in vivo. DPA-derived TBBM and fat were compared with established methods in 13 subjects (aged 24-94 y) who underwent measurement of body density (Db), total-body water (TBW), potassium (TBK), calcium (TBCa, delayed-gamma neutron activation), and nitrogen (prompt-gamma neutron activation). TBBM was highly correlated with TBCa (r = 0.95, p less than 0.001) and the slope of TBCa vs TBBM (0.34) was similar to Ca content of ashed skeleton (0.34-0.38). DPA-measured fat (means +/- SD, 16.7 +/- 4.9 kg) correlated significantly (r = 0.79-0.94; p less than 0.01-0.001) with fat established by Db (16.3 +/- 5.4 kg), TBW (16.0 +/- 4.3 kg), TBK (17.7 +/- 4.6 kg), combined TBW-neutron activation (17.6 +/- 5.9 kg), and means of all four methods (16.9 +/- 4.8 kg). DPA thus offers a new opportunity to study human skeleton in vivo and to quantify fat by a method independent from the classical assumption that bone represents a fixed fraction of fat-free body mass.

  8. 3D bone mineral density distribution and shape reconstruction of the proximal femur from a single simulated DXA image: an in vitro study

    NASA Astrophysics Data System (ADS)

    Whitmarsh, Tristan; Humbert, Ludovic; De Craene, Mathieu; del Río Barquero, Luis M.; Fritscher, Karl; Schubert, Rainer; Eckstein, Felix; Link, Thomas; Frangi, Alejandro F.

    2010-03-01

    Area Bone Mineral Density (aBMD) measured by Dual-energy X-ray Absorptiometry (DXA) is an established criterion in the evaluation of hip fracture risk. The evaluation from these planar images, however, is limited to 2D while it has been shown that proper 3D assessment of both the shape and the Bone Mineral Density (BMD) distribution improves the fracture risk estimation. In this work we present a method to reconstruct both the 3D bone shape and 3D BMD distribution of the proximal femur from a single DXA image. A statistical model of shape and a separate statistical model of the BMD distribution were automatically constructed from a set of Quantitative Computed Tomography (QCT) scans. The reconstruction method incorporates a fully automatic intensity based 3D-2D registration process, maximizing the similarity between the DXA and a digitally reconstructed radiograph of the combined model. For the construction of the models, an in vitro dataset of QCT scans of 60 anatomical specimens was used. To evaluate the reconstruction accuracy, experiments were performed on simulated DXA images from the QCT scans of 30 anatomical specimens. Comparisons between the reconstructions and the same subject QCT scans showed a mean shape accuracy of 1.2mm, and a mean density error of 81mg/cm3. The results show that this method is capable of accurately reconstructing both the 3D shape and 3D BMD distribution of the proximal femur from DXA images used in clinical routine, potentially improving the diagnosis of osteoporosis and fracture risk assessments at a low radiation dose and low cost.

  9. Comparison of DXA Scans and Conventional X-rays for Spine Morphometry and Bone Age Determination in Children.

    PubMed

    Hoyer-Kuhn, Heike; Knoop, Kai; Semler, Oliver; Kuhr, Kathrin; Hellmich, Martin; Schoenau, Eckhard; Koerber, Friederike

    2016-01-01

    Conventional lateral spine and hand radiographs are the standard tools to evaluate vertebral morphometry and bone age in children. Beside bone mineral density analyses, dual-energy X-ray absorptiometry (DXA) measurements with lower radiation exposure provide high-resolution scans which are not approved for diagnostic purposes. Data about the comparability of conventional radiographs and DXA in children are missing yet. The purpose of the trial was to evaluate whether conventional hand and spine radiographs can be replaced by DXA scans to diminish radiation exposure. Thirty-eight children with osteogenesis imperfecta or secondary osteoporosis or short stature (male, n=20; age, 5.0-17.0 yr) were included and assessed once by additional DXA (GE iDXA) of the spine or the left hand. Intraclass correlation coefficients (ICCs) were used to express agreement between X-ray and iDXA assessment. Evaluation of the spine morphometry showed reasonable agreement between iDXA and radiography (ICC for fish-shape, 0.75; for wedge-shape, 0.65; and for compression fractures, 0.70). Bone age determination showed excellent agreement between iDXA and radiography (ICC, 0.97). IDXA-scans of the spine in a pediatric population should be used not only to assess bone mineral density but also to evaluate anatomic structures and vertebral morphometry. Therefore, iDXA can replace some radiographs in children with skeletal diseases. PMID:26059565

  10. On new opportunities for absorptiometry.

    PubMed

    Ferretti, J L; Schiessl, H; Frost, H M

    1998-01-01

    Mechanical loads cause bone strains; and muscle forces, not body weight, cause the largest strains. The strains help to control the effects of bone modeling and remodeling on bone strength and "mass." When strains exceed a threshold range, modeling increases bone strength and "mass." When strains stay below a smaller threshold range, remodeling begins removing bone next to marrow. As a result, increasing muscle strength increases bone strength and "mass," and decreasing muscle strength decreases bone strength and "mass." Estrogen apparently lowers the remodeling threshold, which reduces bone losses. Loss of estrogen raises that threshold to cause losses of bone next to marrow. Such facts help to explain: 1. Bone loss in aging adults. 2. An increase in bone "mass" in girls at menarche. 3. The loss of bone during menopause. 4. The greater bone "mass" in obese than in slender subjects, and in weightlifters than in marathon runners. 5. And the pathogenesis of physiologic osteopenias and true osteoporoses. Thus new standards are needed for the relationships between bone and muscle strengths, and as functions of sex, age, race, disease, endocrine status, nutrition, vitamin and mineral intakes, medications, puberty, and menopause. Obtaining those standards and studying such relationships provide many new opportunities for studies that involve dual energy X-ray absorptiometry (DXA) and peripheral quantitative computer tomography (pQCT) and, perhaps some day, ultrasound and magnetic resonance imaging (MRI) techniques. PMID:15304912

  11. Accuracy of DXA scanning of the thoracic spine: cadaveric studies comparing BMC, areal BMD and geometric estimates of volumetric BMD against ash weight and CT measures of bone volume.

    PubMed

    Sran, Meena M; Khan, Karim M; Keiver, Kathy; Chew, Jason B; McKay, Heather A; Oxland, Thomas R

    2005-12-01

    Biomechanical studies of the thoracic spine often scan cadaveric segments by dual energy X-ray absorptiometry (DXA) to obtain measures of bone mass. Only one study has reported the accuracy of lateral scans of thoracic vertebral bodies. The accuracy of DXA scans of thoracic spine segments and of anterior-posterior (AP) thoracic scans has not been investigated. We have examined the accuracy of AP and lateral thoracic DXA scans by comparison with ash weight, the gold-standard for measuring bone mineral content (BMC). We have also compared three methods of estimating volumetric bone mineral density (vBMD) with a novel standard-ash weight (g)/bone volume (cm3) as measured by computed tomography (CT). Twelve T5-T8 spine segments were scanned with DXA (AP and lateral) and CT. The T6 vertebrae were excised, the posterior elements removed and then the vertebral bodies were ashed in a muffle furnace. We proposed a new method of estimating vBMD and compared it with two previously published methods. BMC values from lateral DXA scans displayed the strongest correlation with ash weight (r=0.99) and were on average 12.8% higher (p<0.001). As expected, BMC (AP or lateral) was more strongly correlated with ash weight than areal bone mineral density (aBMD; AP: r=0.54, or lateral: r=0.71) or estimated vBMD. Estimates of vBMD with either of the three methods were strongly and similarly correlated with volumetric BMD calculated by dividing ash weight by CT-derived volume. These data suggest that readily available DXA scanning is an appropriate surrogate measure for thoracic spine bone mineral and that the lateral scan might be the scan method of choice. PMID:15616862

  12. Comparison of nuclear magnetic resonance spectroscopy with dual-photon absorptiometry and dual-energy X-ray absorptiometry in the measurement of thoracic vertebral bone mineral density: compressive force versus bone mineral.

    PubMed

    Myers, T J; Battocletti, J H; Mahesh, M; Gulati, M; Wilson, C R; Pintar, F; Reinartz, J

    1994-05-01

    31P nuclear magnetic resonance spectroscopy (NMRS) measurements were made on human T2 and T3 vertebral bodies. The bone mineral content (BMC) of isolated vertebral bodies minus the posterior elements and disks was measured using (1) NMRS on a 3.5 T, 85 mm bore GE Medical Systems NT-150 superconducting spectrometer, (2) a Lunar Corporation DPX-L dual-energy X-ray absorptiometry (DXA) scanner in an anterior-posterior (AP) orientation, (3) a Norland Corporation XR26 DXA scanner, also in an AP direction, and (4) a Norland Corporation model 2600 dual-photon absorptiometry (DPA) densitometer in both the AP and superior-inferior (SI) directions. Vertebral body volumes were measured using a water displacement technique to determine volume bone mineral densities (VBMD). They were then compressed to failure using an electrohydraulic testing device, followed by ashing in a muffle furnace at 700 degrees C for 18 h. Correlations of BMC between NMRS and DPA, DXA and ashing were excellent (0.96 < or = r < or = 0.99); in a one-way analysis of variance (ANOVA) test, means were not statistically different at a p level of 0.757. The correlations of VBMD between NMRS and the other methods were not as good (0.83 < or = r < or = 0.95); in a one-way ANOVA test, means were not statistically different at a p level of 0.089. BMC was a better predictor of ultimate compressive failure than VBMD for all six methods. For NMRS, the regression coefficient for BMC was r2 = 0.806, compared with r2 = 0.505 for VBMD. NMRS may prove an alternative to present methods of determining bone mineral. PMID:8069051

  13. Measurement of midfemoral shaft geometry: repeatability and accuracy using magnetic resonance imaging and dual-energy X-ray absorptiometry.

    PubMed

    Woodhead, H J; Kemp, A F; Blimkie CJR; Briody, J N; Duncan, C S; Thompson, M; Lam, A; Howman-Giles, R; Cowell, C T

    2001-12-01

    Although macroscopic geometric architecture is an important determinant of bone strength, there is limited published information relating to the validation of the techniques used in its measurement. This study describes new techniques for assessing geometry at the midfemur using magnetic resonance imaging (MRI) and dual-energy X-ray absorptiometry (DXA) and examines both the repeatability and the accuracy of these and previously described DXA methods. Contiguous transverse MRI (Philips 1.5T) scans of the middle one-third femur were made in 13 subjects, 3 subjects with osteoporosis. Midpoint values for total width (TW), cortical width (CW), total cross-sectional area (TCSA), cortical cross-sectional area (CCSA), and volumes from reconstructed three-dimensional (3D) images (total volume [TV] and cortical volume [CVol]) were derived. Midpoint TW and CW also were determined using DXA (Lunar V3.6, lumbar software) by visual and automated edge detection analysis. Repeatability was assessed on scans made on two occasions and then analyzed twice by two independent observers (blinded), with intra- and interobserver repeatability expressed as the CV (CV +/- SD). Accuracy was examined by comparing MRI and DXA measurements of venison bone (and Perspex phantom for MRI), against "gold standard" measures made by vernier caliper (width), photographic image digitization (area) and water displacement (volume). Agreement between methods was analyzed using mean differences (MD +/- SD%). MRI CVs ranged from 0.5 +/- 0.5% (TV) to 3.1 +/- 3.1% (CW) for intraobserver and 0.55 +/- 0.5% (TV) to 3.6 +/- 3.6% (CW) for interobserver repeatability. DXA results ranged from 1.6 +/- 1.5% (TW) to 4.4 +/- 4.5% (CW) for intraobserver and 3.8 +/- 3.8% (TW) to 8.3 +/- 8.1% (CW) for interobserver variation. MRI accuracy was excellent for TV (3.3 +/- 6.4%), CVol (3.5 +/- 4.0%), TCSA (1.8 +/- 2.6%), and CCSA (1.6 +/- 4.2%) but not TW (4.1 +/- 1.4%) or CW (16.4 +/14.9%). DXA results were TW (6.8 +/- 2

  14. Dual-energy x-ray absorptiometry using 2D digital radiography detector: application to bone densitometry

    NASA Astrophysics Data System (ADS)

    Dinten, Jean-Marc; Robert-Coutant, Christine; Darboux, Michel

    2001-06-01

    Dual Energy X-Rays Absorptiometry (DXA) is commonly used to separate soft tissues and bone contributions in radiographs. This decomposition leads to bone mineral density (BMD) measurement. Most clinical systems use pencil or fan collimated X-Rays beam with mono detectors or linear arrays. On these systems BMD is computed from bi-dimensional (2D) images obtained by scanning. Our objective is to take advantage of the newly available flat panels detectors and to propose a DXA approach without scanning, based on the use of cone beam X-Rays associated with a 2D detector. This approach yields bone densitometry systems with an equal X and Y resolution, a fast acquisition and a reduced risk of patient motion.Scatter in this case becomes an important issue. While scattering is insignificant on collimated systems, its level and geometrical structure may severely alter BMD measurement on cone beam systems. In our presentation an original DXA method taking into account scattering is proposed. This new approach leads to accurate BMD values.In order to evaluate the accuracy of our new approach, a phantom representative of the spine regions tissue composition (bone, fat , muscle) has been designed. The comparison between the expected theoretical and the reconstructed BMD values validates the accuracy of our method. Results on anthropomorphic spine and hip regions are also presented.

  15. Radial quantitative ultrasound and dual energy x-ray absorptiometry: intermethod agreement for bone status assessment in children.

    PubMed

    Chong, Kar Hau; Poh, Bee Koon; Jamil, Nor Aini; Kamaruddin, Nor Azmi; Deurenberg, Paul

    2015-01-01

    Aim. To validate a radial quantitative ultrasound (QUS) system with dual energy X-ray absorptiometry (DXA), a criterion technique in bone status assessment among children. Methods. Bone health was evaluated using a radial QUS system (Sunlight Omnisense 8000P) to measure the speed of sound (SOS) at one-third distal radius of the nondominant hand and DXA (Hologic QDR) was used to assess whole body bone mineral density (BMD). Results. Some 29.9% of the children were grossly misclassified according to quartiles of BMD and radial SOS. Poor agreement was observed between Z-scores of radial SOS and whole-body BMD (mean difference = 0.6 ± 0.9; 95% limits of agreement = -1.4 to 2.6). With a cut-off value of -1.0, radial SOS yielded satisfactory sensitivity (80%) and specificity (93%) for the detection of children with low BMD. Conclusion. The observed poor agreement in the present study suggests that radial QUS and DXA are not comparable and hence are not interchangeable in evaluating bone status of the children. PMID:25922831

  16. Measurement precision of body composition variables in elite wheelchair athletes, using dual-energy X-ray absorptiometry.

    PubMed

    Keil, Mhairi; Totosy de Zepetnek, Julia O; Brooke-Wavell, Katherine; Goosey-Tolfrey, Victoria L

    2016-01-01

    The purpose of this study was to assess the reproducibility of body composition measurements by dual-energy X-ray absorptiometry (DXA) in 12 elite male wheelchair basketball players (age 31 ± 7 years, BMI 21 ± 2 kg/m(2) and onset of disability 25 ± 9 years). Two whole body scans were performed on each participant in the supine position on the same day, using Lunar Prodigy Advance DXA (GE Lunar, Madison, WI, USA). Participants dismounted from the scanning table and were repositioned in-between the first and second scan. Whole body coefficient of variation (CV) values for bone mineral content (BMC), fat mass (FM) and soft tissue lean mass (LTM) were all <2.0%. With the exclusion of arm FM (CV = 7.8%), CV values ranged from 0.1 to 3.7% for all total body and segmental measurements of BMC, FM and LTM. The least significant change that can be attributed to the effect of treatment intervention in an individual is 1.0 kg, 1.1 kg, 0.12 kg for FM, LTM, and BMC, respectively. This information can be used to determine meaningful changes in body composition when assessed using the same methods longitudinally. Whilst there may be challenges in the correct positioning of an individual with disability that can introduce greater measurement error, DXA is a highly reproducible technique in the estimation of total and regional body composition of elite wheelchair basketball athletes. PMID:25307741

  17. Radial Quantitative Ultrasound and Dual Energy X-Ray Absorptiometry: Intermethod Agreement for Bone Status Assessment in Children

    PubMed Central

    Chong, Kar Hau; Poh, Bee Koon; Jamil, Nor Aini; Kamaruddin, Nor Azmi; Deurenberg, Paul

    2015-01-01

    Aim. To validate a radial quantitative ultrasound (QUS) system with dual energy X-ray absorptiometry (DXA), a criterion technique in bone status assessment among children. Methods. Bone health was evaluated using a radial QUS system (Sunlight Omnisense 8000P) to measure the speed of sound (SOS) at one-third distal radius of the nondominant hand and DXA (Hologic QDR) was used to assess whole body bone mineral density (BMD). Results. Some 29.9% of the children were grossly misclassified according to quartiles of BMD and radial SOS. Poor agreement was observed between Z-scores of radial SOS and whole-body BMD (mean difference = 0.6 ± 0.9; 95% limits of agreement = −1.4 to 2.6). With a cut-off value of −1.0, radial SOS yielded satisfactory sensitivity (80%) and specificity (93%) for the detection of children with low BMD. Conclusion. The observed poor agreement in the present study suggests that radial QUS and DXA are not comparable and hence are not interchangeable in evaluating bone status of the children. PMID:25922831

  18. DXA-derived abdominal fat mass, waist circumference, and blood lipids in postmenopausal women.

    PubMed

    Vatanparast, Hassanali; Chilibeck, Philip D; Cornish, Stephen M; Little, Jonathan P; Paus-Jenssen, Lisa S; Case, Allison M; Biem, H Jay

    2009-08-01

    The purpose of this study was to determine the utility of dual-energy X-ray absorptiometry (DXA)-derived fat mass indices for predicting blood lipid profile in postmenopausal women. A secondary purpose was to determine whether waist circumference is comparable with DXA-derived measurements in predicting blood lipid profile. Subjects were 423 postmenopausal women (age 58.1 +/- 6.3 years). Fat mass was assessed at abdomen, trunk, and total body using DXA. Anthropometric measurements included BMI and waist circumference. Blood samples were analyzed for total cholesterol (TC), triglyceride (TAG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and cholesterol/HDL ratio. Of the DXA-derived measures, abdominal-fat mass was the best predictor of blood lipid profiles. DXA-derived abdominal fat mass and waist girth explained 20 and 16.5% of variation in TC/HDL ratio, respectively, in univariate analysis, with no difference between the slopes of the regression coefficients. Eighty-four percent of subjects were common to the top quartiles of waist circumference and abdominal fat mass, and blood lipid profiles generally worsened across increasing quartiles. DXA-derived abdominal fat mass and waist circumference are of equivalent utility for predicting alterations in blood lipids. Waist circumference is, therefore, ideal as an inexpensive means in primary health-care services for predicting risk of cardiovascular diseases in postmenopausal women. PMID:19343013

  19. Fatness of female field hockey players: Comparison of estimates with different methods.

    PubMed

    Krzykała, M; Konarski, J M; Malina, R M; Rachwalski, K; Leszczyński, P; Ziółkowska-Łajp, E

    2016-06-01

    The aim of the study was to compare relative body fat (% fat) in female field hockey players using several methods with dual-energy X-ray absorptiometry (DXA) as the reference. Participants were 31 Polish hockey players 16-30 years of age, 17 national and 14 youth level. Percent body fat was estimated by DXA (reference method), conventional and segmental bioelectrical impedance analysis (BIA), and predicted from skinfolds (SKF). National and youth team members did not differ in estimated body fat. Correlations between BIA and skinfold estimates of % fat and DXA % fat though significant, were moderate. Both % fat SKF and % fat SBIA differed significantly from % fat DXA, while estimated % fat BIA and % fat DXA did not differ. Limits of agreement were narrow for conventional BIA (-1.20 to 1.71% fat), followed by segmental BIA (3.72-6.09% fat) and broadest for SKF (5.97-9.28% fat). Differences between DXA % fat and estimated % fat with SKF and SBIA increased from the leanest to fattest athletes, whereas conventional BIA overestimated % fat relative to DXA in the small sample of individuals with low relative fatness and underestimated % fat in individuals with elevated relative fatness. Estimated % fat from conventional BIA most closely approximated DXA % fat in this sample of female field hockey players suggesting that the method may be suitable for field surveys to monitor body composition during the season. PMID:27181627

  20. Neonatal body composition: dual-energy X-ray absorptiometry, magnetic resonance imaging, and three-dimensional chemical shift imaging versus chemical analysis in piglets.

    PubMed

    Fusch, C; Slotboom, J; Fuehrer, U; Schumacher, R; Keisker, A; Zimmermann, W; Moessinger, A; Boesch, C; Blum, J

    1999-10-01

    An animal study to evaluate dual-energy x-ray absorptiometry (DXA) and magnetic resonance (MR) imaging and spectroscopy for measurement of neonatal body composition was performed. Twenty-three piglets with body weights ranging from 848 to 7550 g were used. After measuring total body water, animals were killed and body composition was assessed using DXA and MR (1.5 T; MR imaging, T1-weighted sagittal spin-echo sequence; MR spectroscopy, three-dimensional chemical shift imaging) as well as chemical carcass analysis (standard methods) after homogenization. Body composition by chemical analysis (percent of body weight, mean +/- SD) was as follows: body water, 75.3 +/- 3.9%; total protein, 13.9 +/- 8.8%; and total fat, 6.5 +/- 3.7%. Absolute content of fat and total ash was 7-674 and 35-237 g, respectively. Mean hydration of fat-free mass was 0.804 +/- 0.011 g/kg and decreased with increasing body weight (r2 = 0.419) independent of age. Using DXA, bone mineral content was highly correlated with calcium content (r2 = 0.992), and calcium per bone mineral content was 44.1 +/- 4.2%. DXA fat mass correlated with total fat (r2 = 0.961). Using MR, spectroscopy and chemical analysis were highly correlated with fat-to-water ratio (r2 = 0.984) and absolute fat content (r2 = 0.988). Total fat by MR imaging volumetry showed a lower correlation (r2 = 0.913) and overestimated total fat by a factor of 2.46. Conversion equations for DXA were developed (total fat = 1.31 x fat mass measured by DXA--68.8; calcium = 0.402 x bone mineral content + 1.7), which improved precision and accuracy of DXA measurements. In conclusion, both DXA and MR spectroscopy give accurate and precise estimates of neonatal body composition and may become valuable tools for the noninvasive assessment of neonatal growth and nutritional status. PMID:10509370

  1. Prediction of fat-free body mass from bioelectrical impedance and anthropometry among 3-year-old children using DXA

    PubMed Central

    Ejlerskov, Katrine T.; Jensen, Signe M.; Christensen, Line B.; Ritz, Christian; Michaelsen, Kim F.; Mølgaard, Christian

    2014-01-01

    For 3-year-old children suitable methods to estimate body composition are sparse. We aimed to develop predictive equations for estimating fat-free mass (FFM) from bioelectrical impedance (BIA) and anthropometry using dual-energy X-ray absorptiometry (DXA) as reference method using data from 99 healthy 3-year-old Danish children. Predictive equations were derived from two multiple linear regression models, a comprehensive model (height2/resistance (RI), six anthropometric measurements) and a simple model (RI, height, weight). Their uncertainty was quantified by means of 10-fold cross-validation approach. Prediction error of FFM was 3.0% for both equations (root mean square error: 360 and 356 g, respectively). The derived equations produced BIA-based prediction of FFM and FM near DXA scan results. We suggest that the predictive equations can be applied in similar population samples aged 2–4 years. The derived equations may prove useful for studies linking body composition to early risk factors and early onset of obesity. PMID:24463487

  2. Dual-Energy X-Ray Absorptiometry: Beyond Bone Mineral Density Determination

    PubMed Central

    2016-01-01

    Significant improvements in dual-energy X-ray absorptiometry (DXA) concerning quality, image resolution and image acquisition time have allowed the development of various functions. DXA can evaluate bone quality by indirect analysis of micro- and macro-architecture of the bone, which and improve the prediction of fracture risk. DXA can also detect existing fractures, such as vertebral fractures or atypical femur fractures, without additional radiologic imaging and radiation exposure. Moreover, it can assess the metabolic status by the measurement of body composition parameters like muscle mass and visceral fat. Although more studies are required to validate and clinically use these parameters, it is clear that DXA is not just for bone mineral densitometry. PMID:26996419

  3. Dual-Energy X-Ray Absorptiometry: Beyond Bone Mineral Density Determination.

    PubMed

    Choi, Yong Jun

    2016-03-01

    Significant improvements in dual-energy X-ray absorptiometry (DXA) concerning quality, image resolution and image acquisition time have allowed the development of various functions. DXA can evaluate bone quality by indirect analysis of micro- and macro-architecture of the bone, which and improve the prediction of fracture risk. DXA can also detect existing fractures, such as vertebral fractures or atypical femur fractures, without additional radiologic imaging and radiation exposure. Moreover, it can assess the metabolic status by the measurement of body composition parameters like muscle mass and visceral fat. Although more studies are required to validate and clinically use these parameters, it is clear that DXA is not just for bone mineral densitometry. PMID:26996419

  4. Dual-energy X-ray absorptiometry for measuring total bone mineral content in the rat: study of accuracy and precision.

    PubMed

    Casez, J P; Muehlbauer, R C; Lippuner, K; Kelly, T; Fleisch, H; Jaeger, P

    1994-07-01

    Sequential studies of osteopenic bone disease in small animals require the availability of non-invasive, accurate and precise methods to assess bone mineral content (BMC) and bone mineral density (BMD). Dual-energy X-ray absorptiometry (DXA), which is currently used in humans for this purpose, can also be applied to small animals by means of adapted software. Precision and accuracy of DXA was evaluated in 10 rats weighing 50-265 g. The rats were anesthetized with a mixture of ketamine-xylazine administrated intraperitoneally. Each rat was scanned six times consecutively in the antero-posterior incidence after repositioning using the rat whole-body software for determination of whole-body BMC and BMD (Hologic QDR 1000, software version 5.52). Scan duration was 10-20 min depending on rat size. After the last measurement, rats were sacrificed and soft tissues were removed by dermestid beetles. Skeletons were then scanned in vitro (ultra high resolution software, version 4.47). Bones were subsequently ashed and dissolved in hydrochloric acid and total body calcium directly assayed by atomic absorption spectrophotometry (TBCa[chem]). Total body calcium was also calculated from the DXA whole-body in vivo measurement (TBCa[DXA]) and from the ultra high resolution measurement (TBCa[UH]) under the assumption that calcium accounts for 40.5% of the BMC expressed as hydroxyapatite. Precision error for whole-body BMC and BMD (mean +/- S.D.) was 1.3% and 1.5%, respectively. Simple regression analysis between TBCa[DXA] or TBCa[UH] and TBCa[chem] revealed tight correlations (n = 0.991 and 0.996, respectively), with slopes and intercepts which were significantly different from 1 and 0, respectively.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7950505

  5. Can the material properties of regenerate bone be predicted with non-invasive methods of assessment? Exploring the correlation between dual X-ray absorptiometry and compression testing to failure in an animal model of distraction osteogenesis.

    PubMed

    Monsell, Fergal; Hughes, Andrew William; Turner, James; Bellemore, Michael C; Bilston, Lynne

    2014-04-01

    Evaluation of the material properties of regenerate bone is of fundamental importance to a successful outcome following distraction osteogenesis using an external fixator. Plain radiographs are in widespread use for assessment of alignment and the distraction gap but are unable to detect bone formation in the early stages of distraction osteogenesis and do not quantify accurately the structural properties of the regenerate. Dual X-ray absorptiometry (DXA) is a widely available non-invasive imaging modality that, unlike X-ray, can be used to measure bone mineral content (BMC) and density quantitatively. In order to be useful as a clinical investigation; however, the structural two-dimensional geometry and density distributions assessed by DXA should reflect material properties such as modulus and also predict the structural mechanical properties of the regenerate bone formed. We explored the hypothesis that there is a relationship between DXA assessment of regenerate bone and structural mechanical properties in an animal model of distraction osteogenesis. Distraction osteogenesis was carried out on the tibial diaphysis of 41 male, 12 week old, New Zealand white rabbits as part of a larger study. Distraction started after a latent period of 24 h at a rate of 0.375 mm every 12 h and continued for 10-days, achieving average lengthening of 7.1 mm. Following an 18-day period of consolidation, the regenerate bone was subject to bone density measurements using a total body dual-energy X-ray densitometer. This produced measurement of BMC, bone mineral density (BMD) and volumetric bone mineral density (vBMD). The tibiae were then disarticulated and cleaned of soft tissue before loading in compression to failure using an Instron mechanical testing machine (Instron Corporation, Massachusetts USA). Using Spearman rank correlation and linear regression, there was a significant correlation between vBMD and the Modulus of Elasticity, Yield Stress and Failure Stress of the

  6. Assessing Body Fat of Children by Skinfold Thickness, Bioelectrical Impedance Analysis, and Dual-Energy X-Ray Absorptiometry: A Validation Study Among Malay Children Aged 7 to 11 Years.

    PubMed

    Noradilah, Mohd Jonit; Ang, Yeow Nyin; Kamaruddin, Nor Azmi; Deurenberg, Paul; Ismail, Mohd Noor; Poh, Bee Koon

    2016-07-01

    This study aims to validate skinfold (SKF) and bioelectrical impedance analysis (BIA) against dual-energy X-ray absorptiometry (DXA) in determining body fat percentage (BF%) of Malay children aged 7 to 11 years. A total of 160 children had their BF% assessed using SKF and BIA, with DXA as the criterion method. Four SKF equations (SKFBray, SKFJohnston, SKFSlaughter, and SKFGoran) and 4 BIA equations (BIAManufacturer, BIAHoutkooper, BIARush, and BIAKushner) were used to estimate BF%. Mean age, weight, and height were 9.4 ± 1.1years, 30.5 ± 9.9 kg, and 131.3 ± 8.4 cm. All equations significantly underestimated BF% (P < .05). BIA equations had reasonable agreement with DXA and were independent of BF% with BIAManufacturer being the best equation. Although BIA underestimates BF% as compared with DXA, BIA was more suitable to measure BF% in a population that is similar to this study sample than SKF, suggesting a need to develop new SKF equations that are population specific. PMID:27073201

  7. Calibration and Validation of EchoMRI Whole Body Composition Analysis Based on Chemical Analysis of Piglets, in comparison with the same for DXA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was conducted to evaluate the accuracy and precision of a new quantitative magnetic resonance (QMR) EchoMRI device body for composition analysis (BCA) of infants and to compare it with dual energy X-ray absorptiometry (DXA). The EchoMRI device measured fat, lean, free water, and total water,...

  8. Differences in geriatric anthropometric data between DXA-based subject-specific estimates and non-age-specific traditional regression models

    PubMed Central

    Sukits, Alison L.; McCrory, Jean L.; Cham, Rakié

    2016-01-01

    Age, obesity, and gender can have a significant impact on the anthropometrics of adults aged 65 and older. The aim of this study was to investigate differences in body segment parameters derived using two methods: (1) a dual-energy x-ray absorptiometry (DXA) subject-specific method (Chambers et al., 2010) and (2) traditional regression models (de Leva, 1996). The impact of aging, gender, and obesity on the potential differences between these methods was examined. Eighty-three healthy older adults were recruited for participation. Participants underwent a whole-body DXA scan (Hologic QDR 1000/W). Mass, length, center of mass, and radius of gyration were determined for each segment. In addition, traditional regressions were used to estimate these parameters (de Leva, 1996). A mixed linear regression model was performed (α = 0.05). Method type was significant in every variable of interest except forearm segment mass. The obesity and gender differences that we observed translate into differences associated with using traditional regressions to predict anthropometric variables in an aging population. Our data point to a need to consider age, obesity, and gender when utilizing anthropometric data sets and to develop regression models that accurately predict body segment parameters in the geriatric population, considering gender and obesity. PMID:21844608

  9. Differences in geriatric anthropometric data between DXA-based subject-specific estimates and non-age-specific traditional regression models.

    PubMed

    Chambers, April J; Sukits, Alison L; McCrory, Jean L; Cham, Rakie

    2011-08-01

    Age, obesity, and gender can have a significant impact on the anthropometrics of adults aged 65 and older. The aim of this study was to investigate differences in body segment parameters derived using two methods: (1) a dual-energy x-ray absorptiometry (DXA) subject-specific method (Chambers et al., 2010) and (2) traditional regression models (de Leva, 1996). The impact of aging, gender, and obesity on the potential differences between these methods was examined. Eighty-three healthy older adults were recruited for participation. Participants underwent a whole-body DXA scan (Hologic QDR 1000/W). Mass, length, center of mass, and radius of gyration were determined for each segment. In addition, traditional regressions were used to estimate these parameters (de Leva, 1996). A mixed linear regression model was performed (α = 0.05). Method type was significant in every variable of interest except forearm segment mass. The obesity and gender differences that we observed translate into differences associated with using traditional regressions to predict anthropometric variables in an aging population. Our data point to a need to consider age, obesity, and gender when utilizing anthropometric data sets and to develop regression models that accurately predict body segment parameters in the geriatric population, considering gender and obesity. PMID:21844608

  10. Experimental validation of DXA-based finite element models for prediction of femoral strength.

    PubMed

    Dall'Ara, E; Eastell, R; Viceconti, M; Pahr, D; Yang, L

    2016-10-01

    Osteoporotic fractures are a major clinical problem and current diagnostic tools have an accuracy of only 50%. The aim of this study was to validate dual energy X-rays absorptiometry (DXA)-based finite element (FE) models to predict femoral strength in two loading configurations. Thirty-six pairs of fresh frozen human proximal femora were scanned with DXA and quantitative computed tomography (QCT). For each pair one femur was tested until failure in a one-legged standing configuration (STANCE) and one by replicating the position of the femur in a fall onto the greater trochanter (SIDE). Subject-specific 2D DXA-based linear FE models and 3D QCT-based nonlinear FE models were generated for each specimen and used to predict the measured femoral strength. The outcomes of the models were compared to standard DXA-based areal bone mineral density (aBMD) measurements. For the STANCE configuration the DXA-based FE models (R(2)=0.74, SEE=1473N) outperformed the best densitometric predictor (Neck_aBMD, R(2)=0.66, SEE=1687N) but not the QCT-based FE models (R(2)=0.80, SEE=1314N). For the SIDE configuration both QCT-based FE models (R(2)=0.85, SEE=455N) and DXA neck aBMD (R(2)=0.80, SEE=502N) outperformed DXA-based FE models (R(2)=0.77, SEE=529N). In both configurations the DXA-based FE model provided a good 1:1 agreement with the experimental data (CC=0.87 for SIDE and CC=0.86 for STANCE), with proper optimization of the failure criteria. In conclusion we found that the DXA-based FE models are a good predictor of femoral strength as compared with experimental data ex vivo. However, it remains to be investigated whether this novel approach can provide good predictions of the risk of fracture in vivo. PMID:27341287

  11. A novel approach to fracture-risk-assessment in osteoporosis by ROI-oriented application of the Minkowski-functionals to dual x-ray absorptiometry scans of the hip

    NASA Astrophysics Data System (ADS)

    Boehm, Holger F.; Panteleon, Alexandra; Vogel, Tobias; Burklein, Dominik; Reiser, Maximilian

    2008-03-01

    Fractures of the proximal femur represent the worst complication in osteoporosis with a mortality rate of up to 50% during the first post-traumatic year. Bone mineral density (BMD) as obtained from dual energy x-ray absorptiometry (DXA) is a good predictor of fracture risk. However, there is a considerable overlap in the BMD-results between individuals who have fractured and those who have not. As DXA uses highly standardized radiographic projection images to obtain the densitometric information, it can be postulated that these images contain much more information than just mineral density. Lately, geometric dimensions, e.g. hip axis length (HAL) or femoral neck axis length (FNAL), are considered in conjunction with BMD, which may allow to enhance the predictive potential of bone mass measurements. In recent studies we sucessfully introduced a novel methodology for topological analysis of multi-dimensional graylevel datasets, that, for instance, allows to predict the ultimate mechanical strength of femoral bone specimens. The new topolocial parameters are based on the so called Minkowski Functionals (MF), which represent a set of topographical descriptors that can be used universally. Since the DXA-images are multi-graylevel datasets in 2D obtained in a standardized way, they are ideally suited to be processed by the new method. In this study we introduce a novel algorithm to evaluate DXA-scans of the proximal femur using quantitative image analysis procedures based on the MF in 2D. The analysis is conducted in four defined regions of interest in analogy to the standard densitometric evaluation. The objective is to provide a tool to identifiy individuals with critically reduced mechanical competence of the hip. The result of the new method is compared with the evaluation bone mineral density obtained by DXA, which - at present - is the clinical standard of reference.

  12. Comparison of body composition techniques before and after a 161-km ultramarathon using DXA, BIS and BIA.

    PubMed

    Hew-Butler, T; Holexa, B T; Fogard, K; Stuempfle, K J; Hoffman, M D

    2015-02-01

    The low cost, ease of application and portability of bioelectrical impedance analysis (BIA) and spectroscopy (BIS) devices make them attractive tools for measuring acute changes in body composition before and after exercise, despite potential limitations from active compartmental fluid shifts. The primary study aim was to evaluate use of dual energy x-ray absorptiometry (DXA) against BIA and BIS in measurements of percent body fat (%BF) and percent total body water (%TBW) before and after prolonged endurance exercise. 10 runners were measured pre-race and at race finish. Significant linear relationships were noted pre-race between DXA vs. BIS for %BF (r(2)=0.76; p<0.01) and %TBW (r(2)=0.74; p<0.01). Significant correlations were noted at race finish between DXA vs. BIS for %BF (r(2)=0.64; p<0.01) and %TBW (r(2)=0.66; p<0.05), but only when one outlier was removed. Limits of agreement (LOA) between DXA vs. BIS were wide for both %BF (mean difference of -3.6, LOA between 5.4 and -12.6) and %TBW (mean difference 2.4, LOA between 0.4 and -4.6). LOA was closer between the DXA vs. BIA with DXA measuring slightly higher than BIA for %BF (mean difference of 0.5, LOA between 2.1 and -3.1) and slightly lower than BIA for %TBW (mean difference 0.3, LOA between 3.3 and -2.7). Linear correlations between DXA vs. BIA were not statistically significant for %BF or %TBW before or after the race. DXA measurement of acute changes in %BF and %TBW are not congruent with BIA or BIS measurements. These 3 techniques should not be utilized interchangeably after prolonged endurance running. PMID:25285467

  13. Revised Pediatric Reference Data for the Lateral Distal Femur Measured by Hologic Discovery/Delphi Dual Energy X-Ray Absorptiometry

    PubMed Central

    Zemel, Babette S.; Stallings, Virginia A.; Leonard, Mary B.; Paulhamus, Donna R.; Kecskemethy, Heidi H.; Harcke, H. Theodore; Henderson, Richard C

    2015-01-01

    Background Lateral distal femur (LDF) scans by dual energy x-ray absorptiometry (DXA) are often feasible in children for whom other sites are not measurable. Pediatric reference data for LDF are not available for more recent DXA technology. Aims To assess older pediatric LDF reference data, construct new reference curves for LDF bone mineral density (BMD), and demonstrate the comparability of LDF BMD to other measures of BMD and strength assessed by DXA and by peripheral quantitative computed tomography (pQCT). Methods LDF, spine and whole body scans of 821 healthy children, 5 to 18 years of age, recruited at a single center were obtained using a Hologic Delphi/Discovery system. Tibia trabecular and total BMD (3% site), cortical geometry (38% site) (cortical thickness, section modulus, strain strength index) were assessed by pQCT. Sex and race-specific reference curves were generated using LMS-ChartMaker and Z-scores calculated and compared by correlation analysis. Results Z-scores for LDF BMD based on published findings demonstrated overestimation or underestimation of the prevalence of low BMD-for-age depending on the region of interest considered. Revised LDF reference curves were generated. The new LDF Z-scores were strongly and significantly associated with weight, BMI, spine and whole body BMD Z-scores, and all pQCT Z-scores. Conclusion These findings demonstrate the comparability of LDF measurements to other clinical and research bone density assessment modes, and enable assessment of BMD in children with disabilities, who are particularly prone to low trauma fractures of long bones, and for whom traditional DXA measurement sites are not feasible. PMID:19321369

  14. Best Practices for Dual-Energy X-ray Absorptiometry Measurement and Reporting: International Society for Clinical Densitometry Guidance.

    PubMed

    Lewiecki, E Michael; Binkley, Neil; Morgan, Sarah L; Shuhart, Christopher R; Camargos, Bruno Muzzi; Carey, John J; Gordon, Catherine M; Jankowski, Lawrence G; Lee, Joon-Kiong; Leslie, William D

    2016-01-01

    Dual-energy X-ray absorptiometry (DXA) is a technology that is widely used to diagnose osteoporosis, assess fracture risk, and monitor changes in bone mineral density (BMD). The clinical utility of DXA is highly dependent on the quality of the scan acquisition, analysis, and interpretation. Clinicians are best equipped to manage patients when BMD measurements are correct and interpretation follows well-established standards. Poor-quality acquisition, analysis, or interpretation of DXA data may mislead referring clinicians, resulting in unnecessary diagnostic evaluations, failure to evaluate when needed, inappropriate treatment, or failure to provide medical treatment, with potentially ineffective, harmful, or costly consequences. Misallocation of limited healthcare resources and poor treatment decisions can be minimized, and patient care optimized, through meticulous attention to DXA instrument calibration, data acquisition and analysis, interpretation, and reporting. This document from the International Society for Clinical Densitometry describes quality standards for BMD testing at DXA facilities worldwide to provide guidance for DXA supervisors, technologists, interpreters, and clinicians. High-quality DXA testing is necessary for correct diagnostic classification and optimal fracture risk assessment, and is essential for BMD monitoring. PMID:27020004

  15. TORSIONAL STIFFNESS AND STRENGTH OF THE PROXIMAL TIBIA ARE BETTER PREDICTED BY FINITE ELEMENT MODELS THAN DXA OR QCT

    PubMed Central

    Edwards, W. Brent; Schnitzer, Thomas J.; Troy, Karen L.

    2013-01-01

    Individuals with spinal cord injury experience a rapid loss of bone mineral below the neurological lesion. The clinical consequence of this bone loss is a high rate of fracture around regions of the knee. The ability to predict the mechanical competence of bones at this location may serve as an important clinical tool to assess fracture risk in the spinal cord injury population. The purpose of this study was to develop, and statistically compare, non-invasive methods to predict torsional stiffness (K) and strength (Tult) of the proximal tibia. Twenty-two human tibiae were assigned to either a “training set” or a “test set” (11 specimens each) and mechanically loaded to failure. The training set was used to develop subject-specific finite element (FE) models, and statistical models based on dual energy x-ray absorptiometry (DXA) and quantitative computed tomography (QCT), to predict K and Tult; the test set was used for cross-validation. Mechanical testing produced clinically relevant spiral fractures in all specimens. All methods were accurate and reliable predictors of K (cross-validation r2 ≥ 0.91; error ≤ 13%), however FE models explained an additional 15% of the variance in measured Tult and illustrated 12–16% less error than DXA and QCT models. Given the strong correlations between measured and FE predicted K (cross-validation r2= 0.95; error = 10%) and Tult (cross-validation r2= 0.91; error = 9%), we believe the FE modeling procedure has reached a level of accuracy necessary to answer clinically relevant questions. PMID:23680350

  16. Associations between pQCT-based fat and muscle area and density and DXA-based total and leg soft tissue mass in healthy women and men

    PubMed Central

    Sherk, Vanessa D; Thiebaud, Robert S; Chen, Zhaojing; Karabulut, Murat; Kim, So Jung; Bemben, Debra A

    2015-01-01

    Peripheral Quantitative Computed Tomography (pQCT) can be used for muscle and fat area and density assessments. These may independently influence muscle and fat mass measurements from Dual Energy X-ray Absorptiometry (DXA). Objective To determine associations between pQCT-derived soft tissue density and area measures and DXA-derived soft tissue mass. Methods Linear regression models were developed based on BMI and calf fat and muscle cross-sectional area (FCSA and MCSA) and density measured by pQCT in healthy women (n=76) and men (n=82) aged 20–59 years. Independent variables for these models were leg and total bone-free lean mass (BFLM) and fat mass (FM) measured by DXA. Results Sex differences (p<0.01) were found in both muscle (Mean±SE: Women: 78.6±0.4; Men: 79.9 ± 0.2 mg/cm3) and fat (Women: 0.8±0.4 Men: 9.1±0.6 mg/cm3) density. BMI, fat density, and age (R2=0.86, p<0.01) best accounted for the variability in total FM. FCSA, BMI, and fat density explained the variance in leg FM (R2=0.87, p<0.01). MCSA and muscle density explained the variance in total (R2=0.65, p<0.01) and leg BFLM (R2=0.70, p<0.01). Conclusion Calf muscle and fat area and density independently predict lean and fat tissue mass. PMID:25524966

  17. Point-of-Care Phalangeal Bone Mineral Density Measurement Can Reduce the Need of Dual-Energy X-Ray Absorptiometry Scanning in Danish Women at Risk of Fracture.

    PubMed

    Holmberg, Teresa; Bech, Mickael; Gram, Jeppe; Hermann, Anne Pernille; Rubin, Katrine Hass; Brixen, Kim

    2016-03-01

    Identifying persons with a high risk of osteoporotic fractures remains a challenge. DXA uptake in women with elevated risk of osteoporosis seems to be depending on distance to scanning facilities. This study aimed to investigate the ability of a small portable scanner in identifying women with reduced bone mineral density (BMD), and to define triage thresholds for pre-selection. Total hip and lumbar spine BMD was measured by dual-energy X-ray absorptiometry and phalangeal BMD by radiographic absorptiometry in 121 Danish women with intermediate or high 10-year fracture probability (aged 61-81 years). Correlation between the two methods was estimated using correlation coefficient (r) and Bland-Altman plots. A moderate correlation between phalangeal BMD versus total hip (r = 0.47) and lumbar spine (r = 0.51), and an AUC on 0.80 was found. The mean difference between phalangeal T score and total hip T score/lumbar spine T score was low, and ranged from -0.26 SD to -0.31 SD depending on site and reference database used for calculation of T scores, but, large variation was seen at an individual level. When applying a triage approach approx. one-third of all DXA scan could be avoided and only 6 % of women in the low-risk group would be false negatives. PMID:26590810

  18. RELIABILITY OF LATERAL DISTAL FEMUR DUAL ENERGY X-RAY ABSORPTIOMETRY MEASURES

    PubMed Central

    Mueske, Nicole M.; Chan, Linda S.; Wren, Tishya A. L.

    2013-01-01

    Dual-energy x-ray absorptiometry (DXA) of the lateral distal femur (LDF) has been suggested for patients with metal implants or joint contractures preventing DXA scanning at conventional anatomical sites. This study assessed variability in LDF DXA measures due to repeat scanning using data from 5 healthy young adults who had 3 unilateral scans with repositioning between scans. Variability due to image analysis was evaluated in 10 children who underwent bilateral LDF scans with each scan being analyzed 3 times by 2 raters. Regions of interest (ROIs) were defined in the anterior distal metaphysis (R1), metadiaphysis (R2), and diaphysis (R3) as described previously. An additional region (R4) was defined in the metaphysis similar to R1 but centered in the medullary canal. Variability was consistently lower for bone mineral density (BMD) than for bone mineral content (BMC) and bone area; R4 was more repeatable than R1; and variability due to repeat scanning was negligible. These results suggest that DXA measures of the lateral distal femur are reliable and may be useful when standard DXA measures cannot be obtained, but it is recommended that a central, rather than anterior, ROI be used in the metaphysis. PMID:23541123

  19. Skeletal Recovery Following Long-Duration Spaceflight Missions as Determined by Preflight and Postflight DXA Scans of 45 Crew Members

    NASA Technical Reports Server (NTRS)

    Sibonga, J. D.; Evans, H. J.; Sung, H. G.; Spector, E. R.; Lang, T. F.; Oganov, V. S.; Bakulin, A. V.; Shackelford, L. C.; LeBlanc, A. D.

    2006-01-01

    Introduction: The loss of bone mineral in astronauts during spaceflight has been investigated throughout the more than 40 years of bone research in space. Consequently, it is a medical requirement at NASA that changes in bone mass be monitored in crew members by measurements of bone mineral density (BMD) with dual-energy x-ray absorptiometry (DXA). This report is the first to evaluate medical data to address the recovery of bone mineral that is lost during spaceflight. Methods: DXA scans are performed before and after flight in astronauts who serve on long-duration missions (4-6 months) to ensure that medical standards for flight certification are met, to evaluate the effects of spaceflight and to monitor the restoration to preflight BMD status after return to Earth. Through cooperative agreements with the Russian Space Agency, the Bone and Mineral Lab at NASA Johnson Space Center (Houston, TX), also had access to BMD data from cosmonauts who had flown on long-duration missions yielding data from a total of 45 individual crew members. Changes in BMD (between 56 different sets of pre- and postflight measurements) were plotted as a function of time (days after landing); plotted data were fitted to an exponential mathematical model that determined i) BMD change at day 0 after landing and ii) the number of days after which 50% of the lost bone was recovered ("Recovery Half-Life"). These fits were performed for BMD of the lumbar spine, trochanter, pelvis, femoral neck and calcaneus. Results: In sum, averaged losses of bone mineral after spaceflight ranged between 2-9% for sites in the axial and appendicular skeleton. The fitted postflight BMD values predicted a 50% recovery of bone loss for all sites within 9 months.

  20. Comparison of Methods for Assessing Body Composition Changes during Weight Loss.

    ERIC Educational Resources Information Center

    Weyers, Anna M.; Mazzetti, Scott A.; Love, Dawn M.; Gomez, Ana L.; Kraemer, William J.; Volek, Jeff S.

    2002-01-01

    Investigated whether dual-energy x-ray absorptiometry (DXA) and air displacement plethysmography (ADP) would detect similar changes in body composition after moderate weight loss. Twenty adults had their body composition measured using DXA and ADP before and after an 8-week weight loss program. Overall, both DXA and ADP detected similar changes in…

  1. CAN DUAL ENERGY X-RAY ABSORPTIOMETRY PROVIDE A VALID ASSESSMENT OF CHANGES IN THIGH MUSCLE MASS WITH STRENGTH TRAINING IN OLDER ADULTS?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A longitudinal strength training (ST) intervention study was conducted in fifty previously sedentary, relatively healthy men (n = 23, 60 [SD=7.5] yr) and women (n = 27, 60 [SD=9.3] yr). One part of the study determined how dual-energy x-ray absorptiometry (DXA) compares to computed tomography (CT) f...

  2. Dual-energy X-ray absorptiometry body composition in patients with secondary osteoporosis.

    PubMed

    Messina, Carmelo; Monaco, Cristian Giuseppe; Ulivieri, Fabio Massimo; Sardanelli, Francesco; Sconfienza, Luca Maria

    2016-08-01

    Due to the tight relationship between bone and soft tissues, there has been an increased interest in body composition assessment in patients with secondary osteoporosis as well as other pathological conditions. Dual-energy X-ray absorptiometry (DXA) is primarily devoted to the evaluation of bone mineral status, but continuous scientific advances of body composition software made DXA a rapid and easily available technique to assess body composition in terms of fat mass and lean mass. As a result, the International Society for Clinical Densitometry (ISCD) recently developed Official Positions regarding the use of this technique for body composition analysis. According to ISCD paper, indications are mainly limited to three conditions: HIV patients treated with antiretroviral agents associated with a risk of lipoatrophy; obese patients undergoing treatment for high weight loss; patients with sarcopenia or muscle weakness. Nevertheless, there are several other interesting clinical applications that were not included in the ISCD position paper, such as body composition assessment in patients undergoing organ transplantation, pulmonary disease as well as all those chronic condition that may lead to malnutrition. In conclusion, DXA body composition offers new diagnostic and research possibilities for a variety of diseases; due to its high reproducibility, DXA has also the potential to monitor body composition changes with pharmacological, nutritional or physic therapeutic interventions. ISCD addressed and recommended a list of clinical condition, but the crescent availability of DXA scans and software improvements may open the use of DXA to other indication in the next future. This article provides an overview of DXA body composition indications in the management of secondary osteoporosis and other clinical indications in adults. PMID:27048946

  3. Muscle analysis using pQCT, DXA and MRI.

    PubMed

    Erlandson, M C; Lorbergs, A L; Mathur, S; Cheung, A M

    2016-08-01

    Skeletal muscle is one of the larger organs of the body and is integrally involved in metabolic processes in both health and disease. The ability to accurately and precisely measure skeletal muscle structure is essential for understanding the changes that occur naturally over the lifespan as well as those observed in chronic disease, and in response to targeted interventions. Musculoskeletal imaging allows for the quantification of skeletal muscle mass and select modalities are also able to determine muscle quality. The purpose of this paper is to review peripheral quantitative computed tomography (pQCT), dual X-ray energy absorptiometry (DXA) and magnetic resonance imaging (MRI) techniques used to assess skeletal muscle size and quality in-vivo. Each modality is briefly described and the strengths and limitations are provided. No single imaging technique will be able to best address every clinical and research question of interest. Selecting the most appropriate imaging device for measuring skeletal muscle depends on access to technology, availability of expertise required for image acquisition and analysis, characteristics of the population, anatomical site of interest, and the level of structural detail required. PMID:27005009

  4. Adaptation of the lateral distal femur DXA scan technique to adults with disabilities.

    PubMed

    Henderson, Richard C; Henderson, Brent A; Kecskemethy, Heidi H; Hidalgo, Sebastian T; Nikolova, Beth Ann; Sheridan, Kevin; Harcke, H Theodore; Thorpe, Deborah E

    2015-01-01

    The technique that best addresses the challenges of assessing bone mineral density in children with neuromuscular impairments is a dual-energy X-ray absorptiometry (DXA) scan of the lateral distal femur. The purpose of this study was to adapt this technique to adults with neuromuscular impairments and to assess the reproducibility of these measurements. Thirty-one adults with cerebral palsy had both distal femurs scanned twice, with the subject removed and then repositioned between each scan (62 distal femurs, 124 scans). Each scan was independently analyzed twice by 3 different technologists of varying experience with DXA (744 analyses). Precision of duplicate analyses of the same scan was good (range: 0.4%-2.3%) and depended on both the specific region of interest and the experience of the technologist. Precision was reduced when comparing duplicate scans, ranging from 7% in the metaphyseal (cancellous) region to 2.5% in the diaphyseal (cortical) region. The least significant change was determined as recommended by the International Society for Clinical Densitometry for each technologist and each region of interest. Obtaining reliable, reproducible, and clinically relevant assessments of bone mineral density in adults with neuromuscular impairments can be challenging. The technique of obtaining DXA scans of the lateral distal femur can be successfully applied to this population but requires a commitment to developing the necessary expertise. PMID:24932899

  5. Usefulness of calcaneal quantitative ultrasound stiffness for the evaluation of bone health in HIV-1-infected subjects: comparison with dual X-ray absorptiometry

    PubMed Central

    Fantauzzi, Alessandra; Floridia, Marco; Ceci, Fabrizio; Cacciatore, Francesco; Vullo, Vincenzo; Mezzaroma, Ivano

    2016-01-01

    Objectives With the development of effective treatments and the resulting increase in life expectancy, bone mineral density (BMD) alteration has emerged as an important comorbidity in human immunodeficiency virus type-1 (HIV-1)-infected individuals. The potential contributors to the pathogenesis of osteopenia/osteoporosis include a higher prevalence of risk factors, combined antiretroviral therapy (cART)-exposure, HIV-1 itself and chronic immune activation/inflammation. Dual-energy X-ray absorptiometry (DXA) is the “gold standard” technique for assessing bone status in HIV-1 population. Methods We conducted a cross-sectional study to investigate bone mineral status in a group of 158 HIV-1-infected subjects. The primary endpoint was the feasibility of calcaneal quantitative ultrasound (QUS) as a screening tool for BMD. All subjects were receiving stable cART and were virologically suppressed (HIV-RNA <37 copies/mL) from at least 12 months. Calcaneal QUS parameters were analyzed to obtain information on bone mass and microarchitecture. The results were compared with those obtained by DXA. Results No correlations were found between DXA/QUS parameters and demographic or HIV-1-specific characteristics, also including cART strategies. In the univariate analyses BMD, QUS indexes, and Fracture Risk Assessment Tool scores conversely showed significant associations with one or more demographic or HIV-1-related variables. Moreover, a significant relationship between calcaneal quantitative ultrasound index/stiffness and femoral/lumbar BMD values from DXA was described. The multivariate analysis showed an independent association between calcaneal quantitative ultrasound index/stiffness and body mass index, higher CD4+ T-cell numbers and low 25-OH D2/D3 vitamin D levels <10 ng/mL (P-values: 0.004, 0.016, and 0.015, respectively). Conclusion As an alternative and/or integrative examination to DXA, calcaneal QUS could be proposed as a useful screening in HIV-1-infected

  6. Cross-Calibration of GE Healthcare Lunar Prodigy and iDXA Dual-Energy X-Ray Densitometers for Bone Mineral Measurements.

    PubMed

    Saarelainen, J; Hakulinen, M; Rikkonen, T; Kröger, H; Tuppurainen, M; Koivumaa-Honkanen, H; Honkanen, R; Hujo, M; Jurvelin, J S

    2016-01-01

    In long-term prospective studies, dual-energy X-ray absorptiometry (DXA) devices need to be inevitably changed. It is essential to assess whether systematic differences will exist between measurements with the new and old device. A group of female volunteers (21-72 years) underwent anteroposterior lumbar spine L2-L4 (n = 72), proximal femur (n = 72), and total body (n = 62) measurements with the Prodigy and the iDXA scanners at the same visit. The bone mineral density (BMD) measurements with these two scanners showed a high linear association at all tested sites (r = 0.962-0.995; p < 0.0001). The average iDXA BMD values were 1.5%, 0.5%, and 0.9% higher than those of Prodigy for lumbar spine (L2-L4) (p < 0.0001), femoral neck (p = 0.048), and total hip (p < 0.0001), respectively. Total body BMD values measured with the iDXA were -1.3% lower (p < 0.0001) than those measured with the Prodigy. For total body, lumbar spine, and femoral neck, the BMD differences as measured with these two devices were independent of subject height and weight. Linear correction equations were developed to ensure comparability of BMD measurements obtained with both DXA scanners. Importantly, use of equations from previous studies would have increased the discrepancy between these particular DXA scanners, especially at hip and at spine. PMID:27239366

  7. Cross-Calibration of GE Healthcare Lunar Prodigy and iDXA Dual-Energy X-Ray Densitometers for Bone Mineral Measurements

    PubMed Central

    Saarelainen, J.; Hakulinen, M.; Rikkonen, T.; Kröger, H.; Tuppurainen, M.; Koivumaa-Honkanen, H.; Honkanen, R.; Hujo, M.; Jurvelin, J. S.

    2016-01-01

    In long-term prospective studies, dual-energy X-ray absorptiometry (DXA) devices need to be inevitably changed. It is essential to assess whether systematic differences will exist between measurements with the new and old device. A group of female volunteers (21–72 years) underwent anteroposterior lumbar spine L2–L4 (n = 72), proximal femur (n = 72), and total body (n = 62) measurements with the Prodigy and the iDXA scanners at the same visit. The bone mineral density (BMD) measurements with these two scanners showed a high linear association at all tested sites (r = 0.962–0.995; p < 0.0001). The average iDXA BMD values were 1.5%, 0.5%, and 0.9% higher than those of Prodigy for lumbar spine (L2–L4) (p < 0.0001), femoral neck (p = 0.048), and total hip (p < 0.0001), respectively. Total body BMD values measured with the iDXA were −1.3% lower (p < 0.0001) than those measured with the Prodigy. For total body, lumbar spine, and femoral neck, the BMD differences as measured with these two devices were independent of subject height and weight. Linear correction equations were developed to ensure comparability of BMD measurements obtained with both DXA scanners. Importantly, use of equations from previous studies would have increased the discrepancy between these particular DXA scanners, especially at hip and at spine. PMID:27239366

  8. Validation of dual x-ray absorptiometry for body-composition assessment of rats exposed to dietary stressors.

    PubMed

    Lukaski, H C; Hall, C B; Marchello, M J; Siders, W A

    2001-01-01

    Evidence of the validity and accuracy of dual x-ray absorptiometry (DXA) to measure soft-tissue composition of laboratory rats with altered body composition associated with nutritional perturbations is lacking. We compared DXA determinations made in prone and supine positions with measurements of chemical composition of 49 male, weanling Sprague-Dawley rats that were fed the basal AIN-93 growth diet, were fed the basal diet modified to contain 30% fat, were fasted for 2 d, were limit fed 6 g of the basal diet daily for 1 wk, or were treated with furosemide (10 mg/kg intraperitoneally 2 h before DXA). DXA produced similar estimates of body mass and soft-tissue composition in the prone and supine positions. DXA estimates of body composition were significantly correlated with reference composition values (R(2) = 0.371-0.999). DXA discriminated treatment effects on body mass, fat-free and bone-free mass, fat mass, and body fatness; it significantly underestimated body mass (1% to 2%) and fat-free and bone-free mass (3%) and significantly overestimated fat mass and body fatness (3% to 25%). The greatest errors occurred in treatment groups in which body mass was diminished and body hydration was decreased. These findings suggest that DXA can determine small changes in fat-free, bone-free mass in response to obesity and weight loss. Errors in DXA determination of fat mass and body fatness associated with extra corporeal fluid and dehydration indicate the need for revision of calculation algorithms for soft-tissue determination. PMID:11448581

  9. A novel DXA-based hip failure index captures hip fragility independent of BMD.

    PubMed

    Sievänen, H; Weynand, L S; Wacker, W K; Simonelli, C; Burke, P K; Ragi, S; Del Rio, L

    2008-01-01

    Capability of a novel dual-energy X-ray absorptiometry (DXA)-based hip failure index (HiFI) to discriminate between hip fracture cases and controls was evaluated. Given the constraints of planar DXA, the femoral neck was assumed a foam-filled ( approximately trabecular bone), thin-walled ( approximately cortical bone) sandwich structure, while HiFI estimated the critical force sufficient to buckle the wall of such a structure. Proximal femur DXA data from 1379 women aged 65yr and older, 268 with prior hip fracture were used. Comparison between standard areal bone mineral density (BMD), femur strength index (FSI), and HiFI was based on areas under receiver operatoring characteristic curves (AUC). The mean femoral neck BMD (SD) was 0.689 (0.109) g/cm(2) among the cases and 0.768 (0.119) g/cm(2) among the controls; the mean FSI 1.33 (0.36) and 1.54 (0.41), and the mean HiFI -0.28 (0.14) and -0.18 (0.15), respectively; all intergroup differences were highly significant (p<0.001). The intergroup difference for HiFI remained significant (p<0.002) after adjusting for age and BMD or FSI. The AUCs were 0.696 (95% confidence interval [CI]: 0.661-0.730) for BMD, 0.665 (0.630-0.700) for FSI, and 0.701 (0.666-0.736) for HiFI. In conclusion, HiFI may capture structural traits that account for femoral neck fragility independently of BMD or FSI. Obviously, the use of actual geometric and structural information from three-dimensional imaging of the femoral neck would help diminish the crude assumptions of the present DXA approach and reveal the true potential of the HiFI approach to gauge hip fragility and identify at-risk individuals for hip fractures. PMID:18456529

  10. Reliability of 2 Different Positioning Protocols for Dual-Energy X-ray Absorptiometry Measurement of Body Composition in Healthy Adults.

    PubMed

    Kerr, Ava; Slater, Gary J; Byrne, Nuala; Nana, Alisa

    2016-01-01

    Dual-energy X-ray absorptiometry (DXA) is an accepted time-efficient method of body composition assessment for total body and regional fat mass (FM), lean mass (LM), and bone mineral content (BMC), but for longitudinal monitoring the measurements must be sufficiently reliable. The aim of this study was to compare the reliability of a new positioning protocol (Nana et al) with the current reference (National Health and Nutrition Examination Survey [NHANES]) protocol and investigate their within-protocol precision. Thirty healthy adults (16 females and 14 males) underwent 4 whole-body DXA scans in succession with full repositioning between scans. The scan order was randomized, with 2 scans undertaken in accordance with the current NHANES protocol and 2 using the Nana et al protocol. Magnitudes of typical errors of measurement and changes in the mean of DXA body composition estimates were assessed as standardized effect sizes. The Nana et al protocol repositioning produced trivial typical errors for total body across all LM estimates except for FM in the arms and trunk which were moderately substantial. The NHANES protocol produced similar typical errors for all measurements in LM except for FM and BMC in the trunk and arms which were substantially larger than the smallest worthwhile effect. The difference between protocols produced substantially large typical errors in estimations of both total body FM and regional FM and BMC, but differences in LM were all less than the smallest worthwhile effect. Although both protocols demonstrated acceptable intratest reliability, the Nana et al protocol produced enhanced precision in regional (arms and trunk) FM and BMC. The protocols were substantially different in body composition assessment especially for FM and thus should not to be interchanged. Anecdotally, subjects felt more comfortable and supported during the scan with the Nana et al protocol. PMID:26343822

  11. Evaluation of mandibular bone mineral density using the dual-energy X-ray absorptiometry technique in edentulous subjects living in an endemic fluorosis region

    PubMed Central

    Buyukkaplan, US; Guldag, MU

    2012-01-01

    Objectives Fluoride is one of the biological trace elements with a strong affinity for osseous, cartilaginous and dental tissue. The dental and skeletal effects of high fluoride intake have already been studied in the literature, but little is known about the effects of high fluoride intake on edentulous mandibles. The purpose of this study was to evaluate the effects of high fluoride intake on mandibular bone mineral density (BMD) measured by the dual-energy X-ray absorptiometry (DXA) technique in edentulous individuals with systemic fluorosis. Methods 32 people who were living in an endemic fluorosis area since birth and 31 people who were living in a non-endemic fluorosis area since birth (control group) participated in this study. Systemic fluorosis was diagnosed in the patients using the sialic acid (NANA)/glycosaminoglycan (GAG) ratio. The BMDs of the mandibles were determined by the DXA technique. Results The serum NANA/GAG ratios in the fluorosis group were significantly lower than those in the control group (p < 0.001). There was also a statistically significant difference in mandibular BMD measurements (p < 0.05) between the systemic fluorosis and control groups, as measured by the DXA technique. Mandibular body BMD measurements were higher in the fluorosis group (1.25 ± 0.24 g cm−2) than in the control group (1.01 ± 0.31 g cm−2). Conclusions The results of the study showed that fluoride intake higher than the optimum level causes increased mandibular BMD in edentulous individuals. Further dose-related studies are needed to determine the effects of high fluoride intake on bony structures of the stomatognathic system. PMID:22241885

  12. Prediction and validation of DXA-derived appendicular lean soft tissue mass by ultrasound in older adults.

    PubMed

    Abe, Takashi; Thiebaud, Robert S; Loenneke, Jeremy P; Young, Kaelin C

    2015-12-01

    The purpose of this study was to develop regression-based prediction equations for estimating dual-energy X-ray absorptiometry (DXA)-derived appendicular lean soft tissue mass (aLM) using ultrasound and to investigate the validity of these equations in 102 Caucasian adults aged 50 to 76 years. The subjects were randomly separated into two groups: 71 in the model-development group (41 men and 30 women) and 31 in the cross-validation group (18 men and 13 women). aLM was measured using a DXA, and muscle thickness (MT) was measured using ultrasound at 9 sites. Stepwise linear regression analysis was used to determine predictive models for DXA-derived aLM from MT variables, sex, and age. A number of ultrasound prediction equations for estimation of aLM were developed and then cross-validated in a subsample of older adults. The results indicated that ultrasound MT and MT × height can be used to accurately and reliably estimate DXA-derived aLM in older Caucasian adults. PMID:26552906

  13. Screening for male osteoporosis at an academic medical center: retrospective analysis of DXA usage patterns over 5 years.

    PubMed

    Ivory, Dedri Markita; Siva, Chokkalingam; Velázquez, Celso; Abdinoor, Abdillahi Abdi

    2012-01-01

    Recent findings suggest that men have higher mortality rates than women after a hip fracture. Although the risk of osteoporotic fractures in men is increasing, male osteoporosis still remains underdiagnosed and undertreated. In general, male osteoporosis is given low priority by policy makers in public health initiatives. The purpose of this study is to examine the patterns of use and gender distribution of DXA (dual-energy X-ray absorptiometry) scan usage at a university medical center in the United States. The total number of DXA scans increased during the study period while the percentage of men studied actually declined. The results of this study may lead to heightened awareness among providers who are caring for male patients at risk for osteoporosis. PMID:21956247

  14. Provider Distribution Changes in Dual-Energy X-Ray Absorptiometry in the Medicare Population Over the Past Decade.

    PubMed

    Intenzo, Charles M; Parker, Laurence; Levin, David C; Kim, Sung M; Rao, Vijay M

    2016-01-01

    Both radiologists as well as nonimaging physicians perform dual-energy X-ray absorptiometry (DXA) imaging in the United States. This study aims to compare provider distribution between these physician groups on the Medicare population, which is the predominant age group of patients evaluated by this imaging procedure. Using the 2 relevant Current Procedural Terminology, Fourth Edition codes for DXA scans, source data were obtained from the CMS Physician Supplier Procedure Summary Master Files from 2003 through 2013. DXA scan procedure volumes for radiologists and nonradiologists on Medicare patients were tabulated. Utilization rates were calculated. From 2003 to 2013, the total number of DXA scans performed on Medicare patients decreased by 2%. However, over the same period, the number of scans performed by radiologists had increased by 25% over nonimaging specialists, whose utilization had declined by approximately the same amount. From 2003 to 2013, the rate of utilization of DXA scans in the Medicare fee-for-service population declined somewhat. However, radiologists continue to gain market share from other specialists and now predominate in this type of imaging by a substantial margin. PMID:26670626

  15. Quantitative Comparison of 2 Dual-Energy X-ray Absorptiometry Systems in Assessing Body Composition and Bone Mineral Measurements.

    PubMed

    Xu, Wenhua; Chafi, Hatim; Guo, Beibei; Heymsfield, Steven B; Murray, Kori B; Zheng, Jolene; Jia, Guang

    2016-01-01

    Dual-energy X-ray absorptiometry (DXA) is widely used in body composition measurement and evaluation. Because of its numerous applications, the probability of instrument discrepancies has increased dramatically. This study quantitatively compares 2 different DXA systems. In this study, 96 subjects (60 female and 36 male, aged 19-82 years) were recruited and scanned using a General Electric Lunar iDXA and a Hologic Discovery scanner. Four measurements (percent fat, total mass, bone mineral density [BMD], and bone mineral content [BMC]) were quantitatively compared in the whole body and in specific anatomic regions (arms, legs, trunk, android, gynoid, head, ribs, and pelvis). A simple linear regression of each measurement was performed to examine the correlation between the 2 systems. Percent fat, total mass, BMC, and BMD were highly correlated between the 2 DXA systems, with correlation r values greater than 0.854 for both the whole body and the individual anatomic regions except for BMC and BMD in ribs. The high correlation between the 2 DXA systems with systematic differences enabled development of calibration equations for extending the multisystem measurements to advanced quantitative analyses. PMID:26206525

  16. The long-term performance of DXA bone densitometers.

    PubMed

    Wells, J; Ryan, P J

    2000-07-01

    Long-term performance of a bone mass measuring device is an important criterion when considering the purchase of such equipment and has been regarded as an important feature of dual X-ray absorptiometry (DXA). The performance of a 6-year-old bone densitometer, the Lunar DPX alpha, which has undertaken 1500 scans annually over this period, was assessed. The short-term coefficient of variation calculated from 15 measurements with repositioning on a single day, using the Lunar aluminium phantom, was 0.242%. Long-term precision, also calculated by the coefficient of variation, was 0.548%. The manufacturer's quality control (QC) procedure was performed daily and allowed the machine to be used except on 15 occasions when bone density measurements could be acquired after rebooting. However, a 2.2% shift in phantom values occurred in July 1996 owing to a photomultiplier tube failure, but this did not produce a failure in the Lunar QC. The optical disc drive was replaced in July 1997. The machine failed to back up on six occasions over the last 2 years owing to software corruption and the acquired femur data were not saved on seven occasions owing to overloading of the memory buffer. In conclusion, expected hardware failure and minor software problems have occurred. We were concerned that the manufacturer's QC failed to detect a 2% shift in the phantom bone mineral density values and recommend regular measurements of the Lunar aluminum phantom in addition to the daily QC measurement of the tissue-equivalent block. We were nevertheless impressed by the long-term stability and reproducibility of the Lunar DPX alpha. PMID:11089465

  17. Predicting visceral adipose tissue by MRI using DXA and anthropometry in adolescents and young adults

    PubMed Central

    Laddu, Deepika R.; Lee, Vinson R.; Blew, Robert M.; Sato, Tetsuya; Lohman, Timothy G.; Going, Scott B.

    2015-01-01

    Objective Accumulation of intra-abdominal (visceral) adipose tissue, independent of total adiposity, is associated with development of metabolic abnormalities such as insulin resistance and type-2 diabetes in children and adults. The objective of this study was to develop prediction equations for estimating visceral adiposity (VAT) measured by magnetic resonance imaging (MRI) using anthropometric variables and measures of abdominal fat mass from DXA in adolescents and young adults. Methods Cross-sectional data was collected from a multiethnic population of seventy males and females, aged 12–25 years, with BMI ranging from 14.5–38.1 kg/m2. Android (AFM; android region as defined by manufacturers instruction) and lumbar L1-L4 regional fat masses were assessed using DXA (GE Lunar Prodigy; GE Lunar Corp, Madison, WI, USA). Criterion measures of intra-abdominal visceral fat were obtained using single-slice MRI (General Electric Signa Model 5x 1.5T) and VAT area was analyzed at the level OF L4–L5. Image analysis was carried out using ZedView 3.1. Results DXA measures of AFM (r=0.76) and L1-L4 (r=0.71) were significantly (P<0.0001) correlated with MRI-measured VAT. DXA AFM, together with gender and weight, explained 62% of the variance in VAT (SEE=10.06 cm2). DXA L1-L4 fat mass with gender explained 54% of the variance in VAT (SEE=11.08 cm2). Addition of the significant interaction, gender × DXA fat mass, improved prediction of VAT from AFM (Radj2=0.61, SEE=10.10cm2) and L1-L4 (Radj2=0.59, SEE=10.39cm2). Conclusion These results demonstrate that VAT is accurately estimated from regional fat masses measured by DXA in adolescents and young adults. PMID:26097436

  18. Errors in dual energy x-ray absorptiometry estimation of body composition induced by hypohydration.

    PubMed

    Rodriguez-Sanchez, Nidia; Galloway, Stuart D R

    2015-02-01

    Dual energy x-ray absorptiometry (DXA) is a popular tool to determine body composition (BC) in athletes, and is used for analysis of fat-free soft tissue mass (FFST) or fat mass (FM) gain/loss in response to exercise or nutritional interventions. The aim of the current study was to assess the effect of exercise-heat stress induced hypohydration (HYP, >2% of body mass (BM) loss) vs. maintenance of euhydration (EUH) on DXA estimates of BC, sum of skinfolds (SF), and impedance (IMP) measurements in athletes. Competitive athletes (23 males and 15 females) recorded morning nude BM for 7 days before the first main trial. Measurements on the first trial day were conducted in a EUH condition, and again after exercise-heat stress induced HYP. On the second trial day, fluid and electrolyte losses were replaced during exercise using a sports drink. A reduction in total BM (1.6 ± 0.4 kg; 2.3 ± 0.4% HYP) and total FFST (1.3 ± 0.4 kg), mainly from trunk (1.1 ± 0.5 kg), was observed using DXA when participants were HYP, reflecting the sweat loss. Estimated fat percent increased (0.3 ± 0.3%), however, total FM did not change (0.1 ± 0.2 kg). SF and IMP declined with HYP (losses of 1.5 ± 2.9% and 1.6 ± 3% respectively) suggesting FM loss. When EUH was maintained there were no significant changes in BM, DXA estimates, or SF values pre to post exercise, but IMP still declined. We conclude that use of DXA for FFST assessment in athletes must ensure a EUH state, particularly when considering changes associated with nutritional or exercise interventions. PMID:25029477

  19. Association between low-frequency ultrasound and hip fractures - comparison with DXA-based BMD

    PubMed Central

    2014-01-01

    Background New methods for diagnosing osteoporosis and evaluating fracture risk are being developed. We aim to study the association between low-frequency (LF) axial transmission ultrasound and hip fracture risk in a population-based sample of older women. Methods The study population consisted of 490 community-dwelling women (78–82 years). Ultrasound velocity (VLF) at mid-tibia was measured in 2006 using a low-frequency scanning axial transmission device. Bone mineral density (BMD) at proximal femur measured using dual-energy x-ray absorptiometry (DXA) was used as the reference method. The fracture history of the participants was collected from December 1997 until the end of 2010. Lifestyle-related risk factors and mobility were assessed at 1997. Results During the total follow-up period (1997–2010), 130 women had one or more fractures, and 20 of them had a hip fracture. Low VLF (the lowest quartile) was associated with increased hip fracture risk when compared with VLF in the normal range (Odds ratio, OR = 3.3, 95% confidence interval (CI) 1.3-8.4). However, VLF was not related to fracture risk when all bone sites were considered. Osteoporotic femoral neck BMD was associated with higher risk of a hip fracture (OR = 4.1, 95% CI 1.6-10.5) and higher risk of any fracture (OR = 2.4, 95% CI 1.6-3.8) compared to the non-osteoporotic femoral neck BMD. Decreased VLF remained a significant risk factor for hip fracture when combined with lifestyle-related risk factors (OR = 3.3, 95% CI 1.2-9.0). Conclusion Low VLF was associated with hip fracture risk in older women even when combined with lifestyle-related risk factors. Further development of the method is needed to improve the measurement precision and to confirm the results. PMID:24934318

  20. 3D structural measurements of the proximal femur from 2D DXA images using a statistical atlas

    NASA Astrophysics Data System (ADS)

    Ahmad, Omar M.; Ramamurthi, Krishna; Wilson, Kevin E.; Engelke, Klaus; Bouxsein, Mary; Taylor, Russell H.

    2009-02-01

    A method to obtain 3D structural measurements of the proximal femur from 2D DXA images and a statistical atlas is presented. A statistical atlas of a proximal femur was created consisting of both 3D shape and volumetric density information and then deformably registered to 2D fan-beam DXA images. After the registration process, a series of 3D structural measurements were taken on QCT-estimates generated by transforming the registered statistical atlas into a voxel volume. These measurements were compared to the equivalent measurements taken on the actual QCT (ground truth) associated with the DXA images for each of 20 human cadaveric femora. The methodology and results are presented to address the potential clinical feasibility of obtaining 3D structural measurements from limited angle DXA scans and a statistical atlas of the proximal femur in-vivo.

  1. DXA estimates of fat in abdominal, trunk and hip regions varies by ethnicity in men

    PubMed Central

    Stults-Kolehmainen, M A; Stanforth, P R; Bartholomew, J B; Lu, T; Abolt, C J; Sinha, R

    2013-01-01

    Objective: The aim of this study was to determine whether the quantity of fat is different across the central (that is, android, trunk) and peripheral (that is, arm, leg and gynoid) regions among young African-American (AA), Asian (AS), Hispanic (HI) and non-Hispanic White (NHW) men. Subjects and Methods: A cohort of 852 men (18–30 years; mean total body fat percent (TBF%)=18.8±7.9, range=3.7–45.4) were assessed for body composition in five body regions via dual-emission X-ray absorptiometry (DXA). Results: HI men (21.8±8.3) had higher TBF% than AA (17.0±10.0), NHW (17.9±7.2) and AS (18.9±8.0) groups (P-values <0.0001). AS had a lower BMI (23.9±3.4) than all other groups, and NHW (24.7±3.2) had a lower BMI than HI (25.7±3.9) and AA (26.5±4.7; P-values<0.0001). A linear mixed model (LMM) revealed a significant ethnicity by region fat% interaction (P<0.0001). HI men had a greater fat% than NHW for every region (adjusted means (%); android: 29.6 vs 23.3; arm: 13.3 vs 10.6; gynoid: 27.2 vs 23.8; leg: 21.2 vs 18.3; trunk: 25.5 vs 20.6) and a greater fat% than AA for every region except the arm. In addition, in the android and trunk regions, HI had a greater fat% than AS, and AS had a higher fat% than AA. Finally, the android fat% for AS was higher than that of NHW. When comparing the region fat% within ethnicities, the android region was greater than the gynoid region for AS and HI, but did not differ for AA and NHW, and the arm region had the least fat% in all ethnicities. Conclusions: Fat deposition and body fat patterning varies by ethnicity. PMID:23507968

  2. Development of a phantom for morphometric X-ray absorptiometry.

    PubMed

    Rea, J A; Blake, G M; Fogelman, I

    2001-04-01

    Morphometric X-ray absorptiometry (MXA) has recently been developed to assess vertebral deformity status using dual energy X-ray absorptiometry (DXA) machines. In contrast to bone densitometry, a vertebral morphometry phantom is not supplied by any machine manufacturer. The aim of this study was to develop a suitable phantom to quantify the accuracy and precision of the vertebral measurement software on three DXA scanners in vitro and to perform a weekly quality control (QC) scan over a 30-month period to evaluate any drift or changes in measurement accuracy over time. The phantom was constructed from Perspex and aluminium to simulate soft tissue and bone, respectively. 13 aluminium rectangles (each 30 mm wide, 25 mm high and 3 mm thick, with edges ("endplates") 6 mm thick) were set into one side of a solid Perspex block to represent the vertebral bodies from the fourth thoracic (T4) to the fourth lumbar (L4). The phantom was scanned on both the Hologic QDR2000plus and the QDR-4500A as well as the Lunar Expert-XL. Three consecutive lateral MXA scans were acquired on the Hologic machines using each of the scan modes available. On the QDR-2000plus, the lateral scan modes available are fast, array and high definition, which are all dual energy modes. These three scan modes are also available on the QDR-4500A, with the addition of a single energy scan mode. Four lateral scans were acquired on the Expert-XL machine using the single scan mode available. Each MXA scan was analysed twice by a trained operator using the standard software supplied by each manufacturer. A QC scan was performed approximately weekly over a 30-month period on only the QDR-4500A machine, and total phantom height was measured from the inferior edge of L4 to the superior edge of T4. Accuracy of "vertebral" height measurement varied between the three DXA machines and between the scan modes available. All underestimated "true" vertebral height by between 0.4% and 8.6%, with the scan modes using finer

  3. Current methods and advances in bone densitometry

    NASA Technical Reports Server (NTRS)

    Guglielmi, G.; Gluer, C. C.; Majumdar, S.; Blunt, B. A.; Genant, H. K.

    1995-01-01

    Bone mass is the primary, although not the only, determinant of fracture. Over the past few years a number of noninvasive techniques have been developed to more sensitively quantitate bone mass. These include single and dual photon absorptiometry (SPA and DPA), single and dual X-ray absorptiometry (SXA and DXA) and quantitative computed tomography (QCT). While differing in anatomic sites measured and in their estimates of precision, accuracy, and fracture discrimination, all of these methods provide clinically useful measurements of skeletal status. It is the intent of this review to discuss the pros and cons of these techniques and to present the new applications of ultrasound (US) and magnetic resonance (MRI) in the detection and management of osteoporosis.

  4. Current methods and advances in bone densitometry.

    PubMed

    Guglielmi, G; Gluer, C C; Majumdar, S; Blunt, B A; Genant, H K

    1995-01-01

    Bone mass is the primary, although not the only, determinant of fracture. Over the past few years a number of noninvasive techniques have been developed to more sensitively quantitate bone mass. These include single and dual photon absorptiometry (SPA and DPA), single and dual X-ray absorptiometry (SXA and DXA) and quantitative computed tomography (QCT). While differing in anatomic sites measured and in their estimates of precision, accuracy, and fracture discrimination, all of these methods provide clinically useful measurements of skeletal status. It is the intent of this review to discuss the pros and cons of these techniques and to present the new applications of ultrasound (US) and magnetic resonance (MRI) in the detection and management of osteoporosis. PMID:11539928

  5. The Performance of Five Bioelectrical Impedance Analysis Prediction Equations against Dual X-ray Absorptiometry in Estimating Appendicular Skeletal Muscle Mass in an Adult Australian Population

    PubMed Central

    Yu, Solomon C. Y.; Powell, Alice; Khow, Kareeann S. F.; Visvanathan, Renuka

    2016-01-01

    Appendicular skeletal muscle mass (ASM) is a diagnostic criterion for sarcopenia. Bioelectrical impedance analysis (BIA) offers a bedside approach to measure ASM but the performance of BIA prediction equations (PE) varies with ethnicities and body composition. We aim to validate the performance of five PEs in estimating ASM against estimation by dual-energy X-ray absorptiometry (DXA). We recruited 195 healthy adult Australians and ASM was measured using single-frequency BIA. Bland-Altman analysis was used to assess the predictive accuracy of ASM as determined by BIA against DXA. Precision (root mean square error (RMSE)) and bias (mean error (ME)) were calculated according to the method of Sheiner and Beal. Four PEs (except that by Kim) showed ASM values that correlated strongly with ASMDXA (r ranging from 0.96 to 0.97, p < 0.001). The Sergi equation performed the best with the lowest ME of −1.09 kg (CI: −0.84–−1.34, p < 0.001) and the RMSE was 2.09 kg (CI: 1.72–2.47). In men, the Kyle equation performed better with the lowest ME (−0.32 kg (CI: −0.66–0.02) and RMSE (1.54 kg (CI: 1.14–1.93)). The Sergi equation is applicable in adult Australians (Caucasian) whereas the Kyle equation can be considered in males. The need remains to validate PEs in other ethnicities and to develop equations suitable for multi-frequency BIA. PMID:27043617

  6. Bone mineralisation of weaned piglets fed a diet free of inorganic phosphorus and supplemented with phytase, as assessed by dual-energy X-ray absorptiometry.

    PubMed

    Skiba, Grzegorz; Weremko, Dagmara; Sobol, Monika; Raj, Stanisława

    2015-01-01

    Sixteen female piglets (58 d of age, 16.8 ± 0.8 kg body weight [BW]) were assigned to two groups (n = 8) and received until day 100 of age (50.3 ± 1.2 kg BW) ad libitum either a diet with a standard (diet C) or low (diet L) total phosphorus (P) content (5.38 and 4.23 g/kg, respectively). Diet C was supplemented with mineral P (1.15 g/kg) and did not contain microbial phytase. Diet L did not contain any inorganic P but 750 FTU/kg of microbial phytase. Despite these treatments, both diets were composed with the same ingredients. Body mineralisation of each gilt was assessed by determining the bone mineral content (BMC), area bone mineral density (BMD) by the dual-energy X-ray absorptiometry (DXA) at days 58, 72, 86 and 100 of age. Feeding diet L caused a higher P digestibility (p = 0.008) measured from days 72 to 86 of age and at 100 days of age a higher BMC and BMD (p ≤ 0.01). Furthermore, the gilts of group L deposited more minerals in the body than control pigs (by 2.4 g/d, p = 0.008). It was found that BMD and BMC were positively correlated with body lean mass and digestible P intake. The results indicated that, even for very young pigs, the addition of microbial phytase instead of inorganic P increases the amount of digestible P covering the requirements of piglets for proper bone mineralisation. Furthermore, it was proved that the DXA method can be successfully applied to measure body fat and lean mass contents as well as bone mineralisation of growing pigs using the same animals. PMID:26062598

  7. Bioelectrical impedance is an accurate method to assess body composition in obese but not severely obese adolescents.

    PubMed

    Verney, Julien; Metz, Lore; Chaplais, Elodie; Cardenoux, Charlotte; Pereira, Bruno; Thivel, David

    2016-07-01

    The aim of this study was to compare total and segmental body composition results between bioimpedance analysis (BIA) and dual x-ray absorptiometry (DXA) scan and to test the reproducibility of BIA in obese adolescents. We hypothesized that BIA offers an accurate and reproducible method to assess body composition in adolescents with obesity. Whole-body and segmental body compositions were assessed by BIA (Tanita MC-780) and DXA (Hologic) among 138 (110 girls and 28 boys) obese adolescents (Tanner stage 3-5) aged 14±1.5years. The BIA analysis was replicated on 3 identical occasions in 32 participants to test the reproducibility of the methods. Whole-body fat mass percentage was significantly higher using the BIA method compared with DXA (40.6±7.8 vs 38.8±4.9%, P<.001), which represents a 4.8% overestimation of the BIA technique compared with DXA. Similarly, fat mass expressed in kilograms is overestimated by 2.8% using BIA (35.8±11.7kg) compared with the DXA measure (34.3±8.7kg) (P<.001), and fat-free mass is underestimated by -6.1% using BIA (P<.001). Except for the right arm and leg percentage of fat mass, all the segmental measures of body composition are significantly different between the 2 methods. Intraclass correlation coefficient and Lin coefficient showed great agreement and concordance between both methods in assessing whole-body composition. Intraclass correlation coefficient between the 3 BIA measures ranged from 0.99 to 1 for body weight, body fat, and fat-free mass. Bioimpedance analysis offers an acceptable and reproducible alternative to assess body composition in obese adolescents, with however a loss of correlation between BIA and DXA with increasing body fat; its validity remains uncertain for segmental analysis among obese youth. PMID:27333957

  8. Comparison of Standing Posture Bioelectrical Impedance Analysis with DXA for Body Composition in a Large, Healthy Chinese Population

    PubMed Central

    Chen, Kuen-Tsann; Chen, Yu-Yawn; Wang, Chia-Wei; Chuang, Chih-Lin; Chiang, Li-Ming; Lai, Chung-Liang; Lu, Hsueh-Kuan; Dwyer, Gregory B.; Chao, Shu-Ping; Shih, Ming-Kuei; Hsieh, Kuen-Chang

    2016-01-01

    Bioelectrical impedance analysis (BIA) is a common method for assessing body composition in research and clinical trials. BIA is convenient but when compared with other reference methods, the results have been inconclusive. The level of obesity degree in subjects is considered to be an important factor affecting the accuracy of the measurements. A total of 711 participants were recruited in Taiwan and were sub-grouped by gender and levels of adiposity. Regression analysis and Bland-Altman analysis were used to evaluate the agreement of the measured body fat percentage (BF%) between BIA and DXA. The BF% measured by the DXA and BIA methods (Tanita BC-418) were expressed as BF%DXA and BF%BIA8, respectively. A one-way ANOVA was used to test the differences in BF% measurements by gender and levels of adiposity. The estimated BF%BIA8 and BF%DXA in the all subjects, male and female groups were all highly correlated (r = 0.934, 0.901, 0.916, all P< 0.001). The average estimated BF%BIA8 (22.54 ± 9.48%) was significantly lower than the average BF%DXA (26.26 ± 11.18%). The BF%BIA8 was overestimated in the male subgroup (BF%DXA< 15%), compared to BF%DXA by 0.45%, respectively. In the other subgroups, the BF%BIA8 values were all underestimated. Standing BIA estimating body fat percentage in Chinese participants have a high correlation, but underestimated on normal and high obesity degree in both male and female subjects. PMID:27467065

  9. Comparison of Standing Posture Bioelectrical Impedance Analysis with DXA for Body Composition in a Large, Healthy Chinese Population.

    PubMed

    Chen, Kuen-Tsann; Chen, Yu-Yawn; Wang, Chia-Wei; Chuang, Chih-Lin; Chiang, Li-Ming; Lai, Chung-Liang; Lu, Hsueh-Kuan; Dwyer, Gregory B; Chao, Shu-Ping; Shih, Ming-Kuei; Hsieh, Kuen-Chang

    2016-01-01

    Bioelectrical impedance analysis (BIA) is a common method for assessing body composition in research and clinical trials. BIA is convenient but when compared with other reference methods, the results have been inconclusive. The level of obesity degree in subjects is considered to be an important factor affecting the accuracy of the measurements. A total of 711 participants were recruited in Taiwan and were sub-grouped by gender and levels of adiposity. Regression analysis and Bland-Altman analysis were used to evaluate the agreement of the measured body fat percentage (BF%) between BIA and DXA. The BF% measured by the DXA and BIA methods (Tanita BC-418) were expressed as BF%DXA and BF%BIA8, respectively. A one-way ANOVA was used to test the differences in BF% measurements by gender and levels of adiposity. The estimated BF%BIA8 and BF%DXA in the all subjects, male and female groups were all highly correlated (r = 0.934, 0.901, 0.916, all P< 0.001). The average estimated BF%BIA8 (22.54 ± 9.48%) was significantly lower than the average BF%DXA (26.26 ± 11.18%). The BF%BIA8 was overestimated in the male subgroup (BF%DXA< 15%), compared to BF%DXA by 0.45%, respectively. In the other subgroups, the BF%BIA8 values were all underestimated. Standing BIA estimating body fat percentage in Chinese participants have a high correlation, but underestimated on normal and high obesity degree in both male and female subjects. PMID:27467065

  10. Seasonal DXA-measured body composition changes in professional male soccer players.

    PubMed

    Milanese, Chiara; Cavedon, Valentina; Corradini, Giuliano; De Vita, Francesco; Zancanaro, Carlo

    2015-01-01

    This work investigated changes in body composition of professional soccer players attending an Italian Serie A club across the competitive season; it is original insofar as body composition was assessed at multiple time points across the season using the accurate three-compartment model provided by Dual-Energy X-Ray Absorptiometry (DXA). Thirty-one players (4 goalkeepers, 13 defenders, 8 midfielders, 6 forwards) underwent DXA and anthropometry at pre-, mid- and end-season. One operator measured whole body and regional body composition (fat mass, FM; fat-free soft tissue mass, FFSTM; mineral mass). Two players were excluded from analysis due to serious injury. Data were analysed with repeated measures ANOVA; factors were season time point and playing position. Results showed that whole-body FM and %FM significantly (P < 0.001) decrease at mid-season (-11.9%; -1.3%, respectively) and end-season (-8.3%; -0.8%, respectively) whereas FFSTM significantly (P < 0.001) increase at mid-season (+1.3%) and end-season (+1.5%). Limited, but significant changes took place in bone mineral content. Some regional (upper and lower limbs, trunk) differences in the pattern of body composition changes across the season were also found. Changes were similar for all playing positions. It was concluded that professional soccer players undergo changes in their FM, FFSTM, and mineral mass across the season with some regional variations, irrespective of the playing position. Changes are mostly positive at mid-season, possibly due to difference in training between the first and second phase of the season. PMID:25773172

  11. Dual X-Ray Absorptiometry Whole Body Composition of Bone Tissue in Rheumatoid Arthritis – a Cross-Sectional Study

    PubMed Central

    POPESCU, Claudiu; BOJINCA, Violeta; OPRIS, Daniela; IONESCU, Ruxandra

    2015-01-01

    Objectives: Previous studies of bone tissue in rheumatoid arthritis (RA) using dual X-ray absorptiometry (DXA) concentrated on regions of interest that were used to diagnose osteoporosis. This study aimed to compare the whole body bone tissue (wbBT) of RA patients with healthy subjects and to identify the RA variables which significantly predict wbBT. Methods: The study was cross-sectionally designed to include postmenopausal RA patients and age-matched healthy female controls. All 107 RA patients and all 104 controls underwent clinical examination, laboratory tests and whole body DXA composition, which recorded total and regional bone indices. Non-parametric standard statistical test and regression models after data normalization were used to assess correlations, associations and differences. Results: Compared to controls, RA patients had significantly lower whole body and regional bone mass (14.9 kg compared to 15.5 kg; p = 0.031). Disease duration (r = -0.402 ; p < 0.001), C-reactive protein (r = -0.279; p = 0.015) and inflammation (2.5% wbBT compared to 2.9%; p = 0.043), radiographic damage (14.3 kg compared to 16.2 kg; p < 0.001), disease activity scores (r = -0.275 ; p = 0.018 for HAQ) are significantly correlated/associated with lower wbBT. Clinical structural damage is associated with lower wbBT and it can significantly predict them (R2 = 0.014; p = 0.001), while glucocorticoid treatment, even in low doses, was associated with lower wbBT percent (2.6% compared to 2.8%; p = 0.045). Treatment with biologics was associated with a lower rate of whole body osteoporosis (0% compared to 22.2%; p = 0.013). Conclusions: The main associated factors with the generalized bone loss in female RA patients are disease duration and disease activity. Clinical structural damage is the most powerful predictor of the whole body bone loss. These results suggest a general disturbance of skeletal bone metabolism in RA and could explain a greater risk of fragility fractures of non

  12. Comparisons of a Multi-Frequency Bioelectrical Impedance Analysis to the Dual-Energy X-Ray Absorptiometry Scan in Healthy Young Adults Depending on their Physical Activity Level

    PubMed Central

    Verney, Julien; Schwartz, Chloé; Amiche, Saliha; Pereira, Bruno; Thivel, David

    2015-01-01

    This study aimed at comparing BIA and DXA results in assessing body composition in young adults depending on their physical activity level. Eighty healthy 19–30 years old subjects were enrolled and their body composition (Fat Mass and Fat-Free Mass) was assessed by dual-energy X-ray absorptiometry (DXA) and by a newly developed Bioelectrical Impedance Analyzer (BIA - Tanita MC780). A seven-day physical activity level was assessed using a 3-axial accelerometer. DXA-FM% and BIA-FM% were correlated (p<0.001; r= 0.852; ICC [IC95%]: 0.84 [0.75 – 0.90]; concordance coefficient: 0.844). DXA-FFM and BIA FFM were correlated (p<0.001; r=0.976; ICC [IC95%]: 0.95 [0.93 – 0.97], concordance coefficient: 0.955). DXA and BIA measurements of FM% and FFM were highly correlated in both boys and girls regardless of the physical activity level. Compared with DXA scans, newly developed bioelectrical impedance analyzers provide satisfactory fat mass and lean mass measures in healthy young women and men, despite their physical activity level. PMID:26557191

  13. Efficiency of energy and protein deposition in swine during compensatory growth measured by dual energy X-ray absorptiometry (DXA)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was conducted to examine the effects of controlled intake, dietary protein (CP) level, and ractopamine supplementation on growth, body composition, and the efficiency of energy and protein deposition in pigs during uninterrupted or compensatory growth from 60 to 100 kg. Seven groups of pigs ...

  14. Measuring body composition in dogs using multifrequency bioelectrical impedance analysis and dual energy X-ray absorptiometry.

    PubMed

    Rae, L S; Vankan, D M; Rand, J S; Flickinger, E A; Ward, L C

    2016-06-01

    Thirty-five healthy, neutered, mixed breed dogs were used to determine the ability of multifrequency bioelectrical impedance analysis (MFBIA) to predict accurately fat-free mass (FFM) in dogs using dual energy X-ray absorptiometry (DXA)-measured FFM as reference. A second aim was to compare MFBIA predictions with morphometric predictions. MFBIA-based predictors provided an accurate measure of FFM, within 1.5% when compared to DXA-derived FFM, in normal weight dogs. FFM estimates were most highly correlated with DXA-measured FFM when the prediction equation included resistance quotient, bodyweight, and body condition score. At the population level, the inclusion of impedance as a predictor variable did not add substantially to the predictive power achieved with morphometric variables alone; in individual dogs, impedance predictors were more valuable than morphometric predictors. These results indicate that, following further validation, MFBIA could provide a useful tool in clinical practice to objectively measure FFM in canine patients and help improve compliance with prevention and treatment programs for obesity in dogs. PMID:27256027

  15. Executive Summary of the 2015 ISCD Position Development Conference on Advanced Measures From DXA and QCT: Fracture Prediction Beyond BMD.

    PubMed

    Shepherd, John A; Schousboe, John T; Broy, Susan B; Engelke, Klaus; Leslie, William D

    2015-01-01

    There have been many scientific advances in fracture risk prediction beyond bone density. The International Society for Clinical Densitometry (ISCD) convened a Position Development Conference (PDC) on the use of dual-energy X-ray absorptiometry beyond measurement of bone mineral density for fracture risk assessment, including trabecular bone score and hip geometry measures. Previously, no guidelines for nonbone mineral density DXA measures existed. Furthermore, there have been advances in the analysis of quantitative computed tomography (QCT) including finite element analysis, QCT of the hip, DXA-equivalent hip measurements, and opportunistic screening that were not included in the previous ISCD positions. The topics and questions for consideration were developed by the ISCD Board of Directors and the Scientific Advisory Committee and were designed to address the needs of clinical practitioners. Three task forces were created and asked to conduct comprehensive literature reviews to address specific questions. The task forces included participants from many countries and a variety of interests including academic institutions and private health care delivery organizations. Representatives from industry participated as consultants to the task forces. Task force reports with proposed position statements were then presented to an international panel of experts with backgrounds in bone densitometry. The PDC was held in Chicago, Illinois, USA, contemporaneously with the Annual Meeting of the ISCD, February 26 through February 28, 2015. This Executive Summary describes the methodology of the 2015 PDC on advanced measures from DXA and QCT and summarizes the approved official positions. Six separate articles in this issue will detail the rationale, discussion, and additional research topics for each question the task forces addressed. PMID:26277847

  16. Assessment of bone mineral density by DXA and the trabecular microarchitecture of the calcaneum by texture analysis in pre- and postmenopausal women in the evaluation of osteoporosis.

    PubMed

    Karunanithi, R; Ganesan, S; Panicker, T M R; Korath, M Paul; Jagadeesan, K

    2007-10-01

    The in vivo evaluation of trabecular bone structure could be useful in the diagnosis of osteoporosis for the characterization of therapeutic response and understanding the role of parameters other than bone mineral density (BMD) in defining skeletal status. This study was made to evaluate changes taking place in the trabecular architecture of bone with age and menopausal status in women. The findings are compared with the femoral neck bone as well as the trochantar bone mineral density determined by dual energy X-ray absorptiometry (DXA), which is a standard reference test for evaluation of osteoporosis. Seventy females were recruited for the study, 25 premenopausal (mean age ± SD: 39.4 ± 3.8) and 45 postmenopausal (mean age ± SD: 57.9 ± 7.9) women. The right femoral neck bone mineral density was measured for them by dual energy X-ray absorptiometry (DXA). For the same individuals, lateral view radiographs of the right calcaneum were taken as well. The radiographs were digitized and the region of interest (ROI) of 256 × 256 pixels was selected, the run length matrix was computed for calculating seven parameters [Table 1] and the two dimensional fast Fourier transform of the image was calculated. Using the FFT, the power spectral density (PSD) was derived and the root mean square (RMS) value was determined. Our results confirm that age has a significant influence on the texture of the trabecular bone and bone mineral density. PMID:21224926

  17. Agreement between bioelectrical impedance and dual energy X-ray absorptiometry in assessing fat, lean and bone mass changes in adults after a lifestyle intervention.

    PubMed

    Macfarlane, Duncan J; Chan, Natalie T-Y; Tse, Michael A; Joe, Glen M

    2016-06-01

    We aimed to assess the agreement of a commercially available bioelectrical impedance analysis (BIA) device in measuring changes in fat, lean and bone mass over a 10-week lifestyle intervention, with dual energy X-ray absorptiometry (DXA) as reference. A sample of 136 volunteers (18-66 years) underwent a physical activity intervention to enhance lean mass and reduce fat mass. BIA (Tanita BC545) and DXA (Hologic Explorer) measures of whole-body composition were taken at baseline and at the end of the intervention. After an average of 74 ± 18 days intervention, DXA showed significant changes in 2 of 3 outcome variables: reduced fat mass of 0.802 ± 1.092 kg (P < 0.001), increased lean mass of 0.477 ± 0.966 kg (P < 0.001); minor non-significant increase of 0.007 ± 0.041 kg of bone mass (P = 0.052). The respective changes in BIA measures were a significant reduction of 0.486 ± 1.539 kg fat (P < 0.001), but non-significant increases of 0.084 ± 1.201 kg lean mass (P = 0.425), and 0.014 ± 0.091 kg bone (P = 0.074). Significant, but moderately weak, correlations were seen in absolute mass changes between DXA and BIA: 0.511 (fat), 0.362 (lean) and 0.172 (bone). Compared to DXA, BIA demonstrated mediocre agreement to changes in fat mass, but poor agreement to lean mass changes. BIA significantly underestimated the magnitude of changes in fat and lean mass compared to DXA. PMID:26451461

  18. Changes in fat and skeletal muscle with exercise training in obese adolescents: comparison of whole-body MRI and dual energy X-ray absorptiometry

    PubMed Central

    Lee, SoJung; Kuk, Jennifer L.

    2013-01-01

    Objective We examined skeletal muscle (SM) and fat distribution using whole-body MRI in response to aerobic (AE) versus resistance exercise (RE) training in obese adolescents and whether DXA provides similar estimates of fat and SM change as MRI. Design and Methods Thirty-nine obese boys (12–18 yr) were randomly assigned to one of three 3-month interventions: AE (n=14), RE (n=14) or a control (n=11). Results At baseline, MRI-measured total fat was significantly greater than DXA-measured total fat [Δ=3.1 kg (95% CI: −0.4 to 7.4 kg, P<0.05)], wherein underestimation by DXA was greatest in those with the highest total fat. Overall, the changes in total fat were not significantly different between MRI and DXA [Δ= −0.4 kg (95% CI: −3.5 to 2.6 kg, P>0.05)], but DXA tended to overestimate MRI fat losses in those with larger fat losses. MRI-measured SM and DXA-measured LBM (lean body mass) were significantly correlated, but as expected the absolute values were different at baseline [Δ= −28.4 kg (95% CI: −35.4 to −21.3 kg, P<0.05)]. Further, DXA overestimated MRI gains in SM in those with larger SM gains. Conclusions Although DXA and MRI-measured total and regional measures tended to be correlated at baseline and changes with exercise, there were substantial differences in the absolute values derived using DXA versus MRI. Further, there were systemic biases in the estimation between the methods wherein DXA tended to overestimate fat losses and SM gains compared to MRI. Thus, the changes in body composition observed are influenced by the method employed. PMID:23512818

  19. Discriminatory Performance of the Calcaneal Quantitative Ultrasound and Osteoporosis Self-Assessment Tool to Select Older Women for Dual-Energy X-ray Absorptiometry.

    PubMed

    McLeod, Katherine M; Johnson, Shanthi; Rasali, Drona; Verma, Ashok

    2015-01-01

    The objective of this cross-sectional study was to evaluate the accuracy of the calcaneal quantitative ultrasound (QUS) and the Osteoporosis Self-Assessment Tool (OST) in identifying older women with osteoporosis as defined by dual-energy X-ray absorptiometry (DXA), and to establish optimal cutoffs to determine risk. We assessed bone mineral density of the femoral neck and lumbar spine using DXA and subsequent calcaneal QUS and OST measurements in 174 women aged 50-80 years. Pearson product correlation coefficients between QUS, OST, and DXA parameters were calculated. Receiver operating characteristic curves were constructed and areas under the curves (AUCs) and optimal thresholds for QUS and OST were defined based on sensitivity, specificity, and likelihood ratio analysis. The ability of calcaneal QUS to identify women with a T-score ≤-2.5 at the femoral neck (AUC = 0.892) consistently outperformed a T-score ≤-2.5 at the lumbar spine (AUC = 0.696) and OST at both the femoral neck and lumbar spine (AUC = 0.706-0.807). Stiffness index cutoff values that fall between 65 and 78 were found to warrant DXA screening, with a cutoff <65 indicating high likelihood of osteoporosis. Further prospective research is needed to examine the gender-related differences of QUS and OST diagnostic performance and their usefulness in clinical practice. PMID:25937306

  20. Effect of ¹⁸F-FDG administration on measurements of bone mineral density and body composition by dual-energy X-ray absorptiometry.

    PubMed

    Kim, Dae-Weung; Kim, Woo Hyoung; Kim, Myoung Hyoun; Kim, Seong Su; Mo, Eun Hee; Lee, Chun Ho; Kim, Chang Guhn

    2013-01-01

    The purpose of this study was to determine whether antecedent administration of ¹⁸F-fluorodeoxyglucose (FDG) used in positron emission tomography (PET) scanning results in corruption of bone mineral density (BMD) and body composition measured by dual-energy X-ray absorptiometry (DXA) system. DXA measurements of BMD and body composition had been performed twice, before and after ¹⁸F-FDG PET scan in 30 patients. The comparison of pre-values and post-values of all BMD values showed a decrease after the injection. However, only the decrease of whole-body BMD (WB-BMD) was statistically significant (p < 0.05). Whole-body fat mass had increased and whole-body lean body mass had decreased after the injection of ¹⁸F-FDG, and these were statistically significant (p < 0.05). There is statistically significant correlation between the injected ¹⁸F-FDG dose and a decrease of WB-BMD (r = -0.405; p < 0.05). The findings of this study suggest that when both ¹⁸F-FDG PET and DXA measurements for whole-body composition are performed in close-time proximity, ¹⁸F-FDG PET scans should follow the DXA measurement. Otherwise, BMD measurements of total femur or lumbar spine could be followed by ¹⁸F-FDG PET in close-time proximity. PMID:23562363

  1. Comparison of phalangeal ultrasound and dual energy X-ray absorptiometry in healthy male and female adolescents.

    PubMed

    Halaba, Zenon P; Konstantynowicz, Jerzy; Pluskiewicz, Wojciech; Kaczmarski, Maciej; Piotrowska-Jastrzebska, Janina

    2005-12-01

    The aims of this study were to determine if there is a correlation between dual energy X-ray absorptiometry (DXA) and phalangeal quantitative ultrasound (QUS) in identifying children and adolescents with low bone density, and to assess if body size influences the results of the two techniques to the same degree. Measurements were performed in 67 girls and 83 boys aged 14 to 19 y using DBM Sonic 1200 (IGEA, Carpi, Italy) and the DXA equipment (LUNAR Radiation Corp., Madison, WI, USA). Twelve adolescents (eight males and four females) reported a past history of nonosteoporotic fractures. Lumbar spine bone mineral density (LS BMD), total body bone mineral density (TB BMD) and total body bone mineral content (TB BMC) correlated positively with age, height, BMI and weight, in both genders. Amplitude-dependent speed of sound (Ad-SOS) was positively correlated with age, height and Tanner stages in both genders and negatively correlated with BMI in females. TB BMD, TB BMC and LS BMD positively correlated with Ad-SOS only in males. In females, there were no significant correlations between Ad-SOS, TB BMD, TB BMC and LS BMD measurements. Twelve teenagers with previous fractures (high impact fractures) were found to have lower DXA and QUS values than age-matched teenagers without fractures but the statistical significance was found only in relation to TB BMD values (p = 0.02). In conclusion, we obtained results similar to those that have been reported by other authors using different QUS techniques. Furthermore, the Ad-SOS measurements taken at the distal metaphysis of the proximal phalanges correlate poorly with LS BMD and TB BMD measured by DXA in growing subjects. PMID:16344124

  2. Estimates of volumetric bone density from projectional measurements improve the discriminatory capability of dual X-ray absorptiometry

    NASA Technical Reports Server (NTRS)

    Jergas, M.; Breitenseher, M.; Gluer, C. C.; Yu, W.; Genant, H. K.

    1995-01-01

    To determine whether estimates of volumetric bone density from projectional scans of the lumbar spine have weaker associations with height and weight and stronger associations with prevalent vertebral fractures than standard projectional bone mineral density (BMD) and bone mineral content (BMC), we obtained posteroanterior (PA) dual X-ray absorptiometry (DXA), lateral supine DXA (Hologic QDR 2000), and quantitative computed tomography (QCT, GE 9800 scanner) in 260 postmenopausal women enrolled in two trials of treatment for osteoporosis. In 223 women, all vertebral levels, i.e., L2-L4 in the DXA scan and L1-L3 in the QCT scan, could be evaluated. Fifty-five women were diagnosed as having at least one mild fracture (age 67.9 +/- 6.5 years) and 168 women did not have any fractures (age 62.3 +/- 6.9 years). We derived three estimates of "volumetric bone density" from PA DXA (BMAD, BMAD*, and BMD*) and three from paired PA and lateral DXA (WA BMD, WA BMDHol, and eVBMD). While PA BMC and PA BMD were significantly correlated with height (r = 0.49 and r = 0.28) or weight (r = 0.38 and r = 0.37), QCT and the volumetric bone density estimates from paired PA and lateral scans were not (r = -0.083 to r = 0.050). BMAD, BMAD*, and BMD* correlated with weight but not height. The associations with vertebral fracture were stronger for QCT (odds ratio [QR] = 3.17; 95% confidence interval [CI] = 1.90-5.27), eVBMD (OR = 2.87; CI 1.80-4.57), WA BMDHol (OR = 2.86; CI 1.80-4.55) and WA-BMD (OR = 2.77; CI 1.75-4.39) than for BMAD*/BMD* (OR = 2.03; CI 1.32-3.12), BMAD (OR = 1.68; CI 1.14-2.48), lateral BMD (OR = 1.88; CI 1.28-2.77), standard PA BMD (OR = 1.47; CI 1.02-2.13) or PA BMC (OR = 1.22; CI 0.86-1.74). The areas under the receiver operating characteristic (ROC) curves for QCT and all estimates of volumetric BMD were significantly higher compared with standard PA BMD and PA BMC. We conclude that, like QCT, estimates of volumetric bone density from paired PA and lateral scans are

  3. Relationship between the Bertin index to estimate visceral adipose tissue from dual-energy X-ray absorptiometry and cardiometabolic risk factors before and after weight loss.

    PubMed

    Karelis, Antony D; Rabasa-Lhoret, Rémi; Pompilus, Roseline; Messier, Virginie; Strychar, Irene; Brochu, Martin; Aubertin-Leheudre, Mylene

    2012-04-01

    The purpose of this study was to investigate the relationship between visceral adipose tissue (VAT), estimated with the Bertin index obtained from dual-energy X-ray absorptiometry (DXA), with cardiometabolic risk factors before and after a weight loss program and compare it with VAT measured with computed tomography (CT) scan. The study population for this analysis included 92 nondiabetic overweight and obese sedentary postmenopausal women (age: 58.1 ± 4.7 years, BMI: 31.8 ± 4.2 kg/m(2)) participating in a weight loss intervention that consisted of a caloric restricted diet with and without resistance training (RT). We measured (i) VAT using CT scan, (ii) body composition (using DXA) from which the Bertin index was calculated, (iii) cardiometabolic risk factors such as insulin sensitivity (using the hyperinsulinenic-euglycemic clamp technique), peak oxygen consumption, blood pressure, plasma lipids, C-reactive protein as well as fasting glucose and insulin. VAT levels for both methods significantly decreased after the weight loss intervention. Furthermore, no differences in VAT levels between both methods were observed before (88.0 ± 25.5 vs. 83.8 ± 22.0 cm(2)) and after (76.8 ± 27.8 vs. 73.6 ± 23.2 cm(2)) the weight loss intervention. In addition, the percent change in VAT levels after the weight loss intervention was similar between both methods (-13.0 ± 16.5 vs. -12.5 ± 12.6%). Moreover, similar relationships were observed between both measures of VAT with cardiometabolic risk factors before and after the weight loss intervention. Finally, results from the logistic regression analysis consistently showed that fat mass and lean body mass were independent predictors of pre- and post-VAT levels for both methods in our cohort. In conclusion, estimated visceral fat levels using the Bertin index may be able to trace variations of VAT after weight loss. This index also shows comparable relationships with cardiometabolic risk factors when compared to VAT

  4. Is bone mineral density measurement using dual-energy X-ray absorptiometry affected by gamma rays?

    PubMed

    Xie, Liang-Jun; Li, Jian-Fang; Zeng, Feng-Wei; Jiang, Hang; Cheng, Mu-Hua; Chen, Yi

    2013-01-01

    The objective of this study was to determine whether the gamma rays emitted from the radionuclide effect bone mineral density (BMD) measurement. Nine subjects (mean age: 56 ± 17.96 yr) scheduled for bone scanning underwent BMD measurement using dual-energy X-ray absorptiometry (DXA) (Hologic/Discovery A) before and 1, 2, and 4 h after injection of technetium-99m-methylene diphosphonate (99mTc-MDP). Ten subjects (mean age: 41 ± 15.47 yr) scheduled for therapy of differentiated thyroid carcinoma with iodine-131 underwent BMD measurement before and 2 h after therapeutic radionuclide administration. All patients were given whole body BMD measurement, including head, arm, ribs, lumbar spine, pelvis, and leg sites. Besides, patients who referred to radioiodine therapy were given total hip and femoral neck BMD measurement as well. No statistically significant changes in BMD values were detected after 99mTc-MDP and iodine-131 administration for all measurement sites (p > 0.05), and individual difference of BMD before and after radionuclide imaging or therapy was less than the least significant change in lumbar spine, total hip, and femoral neck. In conclusion, BMD measurements are not influenced by the gamma rays emitted from technetium-99m and iodine-131. DXA bone densitometry may be performed simultaneously with bone scanning and radioiodine therapy. PMID:23473956

  5. High resolution magnetic resonance imaging of the calcaneus: age-related changes in trabecular structure and comparison with dual X-ray absorptiometry measurements

    NASA Technical Reports Server (NTRS)

    Ouyang, X.; Selby, K.; Lang, P.; Engelke, K.; Klifa, C.; Fan, B.; Zucconi, F.; Hottya, G.; Chen, M.; Majumdar, S.; Genant, H. K.

    1997-01-01

    A high-resolution magnetic resonance imaging (MRI) protocol, together with specialized image processing techniques, was applied to the quantitative measurement of age-related changes in calcaneal trabecular structure. The reproducibility of the technique was assessed and the annual rates of change for several trabecular structure parameters were measured. The MR-derived trabecular parameters were compared with calcaneal bone mineral density (BMD), measured by dual X-ray absorptiometry (DXA) in the same subjects. Sagittal MR images were acquired at 1.5 T in 23 healthy women (mean age: 49.3 +/- 16.6 [SD]), using a three-dimensional gradient echo sequence. Image analysis procedures included internal gray-scale calibration, bone and marrow segmentation, and run-length methods. Three trabecular structure parameters, apparent bone volume (ABV/TV), intercept thickness (I.Th), and intercept separation (I.Sp) were calculated from the MR images. The short- and long-term precision errors (mean %CV) of these measured parameters were in the ranges 1-2% and 3-6%, respectively. Linear regression of the trabecular structure parameters vs. age showed significant correlation: ABV/TV (r2 = 33.7%, P < 0.0037), I.Th (r2 = 26.6%, P < 0.0118), I.Sp (r2 = 28.9%, P < 0.0081). These trends with age were also expressed as annual rates of change: ABV/TV (-0.52%/year), I.Th (-0.33%/year), and I.Sp (0.59%/year). Linear regression analysis also showed significant correlation between the MR-derived trabecular structure parameters and calcaneal BMD values. Although a larger group of subjects is needed to better define the age-related changes in trabecular structure parameters and their relation to BMD, these preliminary results demonstrate that high-resolution MRI may potentially be useful for the quantitative assessment of trabecular structure.

  6. Automatic location of vertebrae on DXA images using random forest regression.

    PubMed

    Roberts, M G; Cootes, Timothy F; Adams, J E

    2012-01-01

    We provide a fully automatic method of segmenting vertebrae in DXA images. This is of clinical relevance to the diagnosis of osteoporosis by vertebral fracture, and to grading fractures in clinical trials. In order to locate the vertebrae we train detectors for the upper and lower vertebral endplates. Each detector uses random forest regressor voting applied to Haar-like input features. The regressors are applied at a grid of points across the image, and each tree votes for an endplate centre position. Modes in the smoothed vote image are endplate candidates, some of which are the neighbouring vertebrae of the one sought. The ambiguity is resolved by applying geometric constraints to the connections between vertebrae, although there can be some ambiguity about where the sequence starts (e.g., is the lowest vertebra L4 or L5, fig 2a). The endplate centres are used to initialise a final phase of active appearance model search for a detailed solution. The method is applied to a dataset of 320 DXA images. Accuracy is comparable to manually initialised AAM segmentation in 91% of images, but multiple grade 3 fractures can cause some edge confusion in severely osteoporotic cases. PMID:23286151

  7. Random field assessment of inhomogeneous bone mineral density from DXA scans can enhance the differentiation between postmenopausal women with and without hip fractures

    PubMed Central

    Dong, Xuanliang Neil; Pinninti, Rajeshwar; Lowe, Timothy; Cussen, Patricia; Ballard, Joyce E.; Paolo, David Di; Shirvaikar, Mukul

    2015-01-01

    Bone mineral density (BMD) measurements from Dual-energy X-ray Absorptiometry (DXA) alone cannot account for all factors associated with the risk of hip fractures. For example, the inhomogeneity of bone mineral density in the hip region also contributes to bone strength. In the stochastic assessment of bone inhomogeneity, the BMD map in the hip region is considered as a random field and stochastic predictors can be calculated by fitting a theoretical model onto the experimental variogram of the BMD map. The objective of this study was to compare the ability of bone mineral density and stochastic assessment of inhomogeneous distribution of bone mineral density in predicting hip fractures for postmenopausal women. DXA scans in the hip region were obtained from postmenopausal women with hip fractures (N=47, Age: 71.3±11.4 years) and without hip fractures (N=45, Age: 66.7±11.4 years). Comparison of BMD measurements and stochastic predictors in assessing bone fragility was based on the area under the receiver operating characteristic curves (AUC) from logistic regression analyses. Although stochastic predictors offered higher accuracy (AUC=0.675) in predicting the risk of hip fractures than BMD measurements (AUC=0.625), such difference was not statistically significant (p=0.548). Nevertheless, the combination of stochastic predictors and BMD measurements had significantly (p=0.039) higher prediction accuracy (AUC=0.748) than BMD measurements alone. This study demonstrates that stochastic assessment of bone mineral distribution from DXA scans can serve as a valuable tool in enhancing the prediction of hip fractures for postmenopausal women in addition to BMD measurements. PMID:25683520

  8. Random field assessment of inhomogeneous bone mineral density from DXA scans can enhance the differentiation between postmenopausal women with and without hip fractures.

    PubMed

    Dong, Xuanliang Neil; Pinninti, Rajeshwar; Lowe, Timothy; Cussen, Patricia; Ballard, Joyce E; Di Paolo, David; Shirvaikar, Mukul

    2015-04-13

    Bone mineral density (BMD) measurements from Dual-energy X-ray Absorptiometry (DXA) alone cannot account for all factors associated with the risk of hip fractures. For example, the inhomogeneity of bone mineral density in the hip region also contributes to bone strength. In the stochastic assessment of bone inhomogeneity, the BMD map in the hip region is considered as a random field and stochastic predictors can be calculated by fitting a theoretical model onto the experimental variogram of the BMD map. The objective of this study was to compare the ability of bone mineral density and stochastic assessment of inhomogeneous distribution of bone mineral density in predicting hip fractures for postmenopausal women. DXA scans in the hip region were obtained from postmenopausal women with hip fractures (N=47, Age: 71.3±11.4 years) and without hip fractures (N=45, Age: 66.7±11.4 years). Comparison of BMD measurements and stochastic predictors in assessing bone fragility was based on the area under the receiver operating characteristic curves (AUC) from logistic regression analyses. Although stochastic predictors offered higher accuracy (AUC=0.675) in predicting the risk of hip fractures than BMD measurements (AUC=0.625), this difference was not statistically significant (p=0.548). Nevertheless, the combination of stochastic predictors and BMD measurements had significantly (p=0.039) higher prediction accuracy (AUC=0.748) than BMD measurements alone. This study demonstrates that stochastic assessment of bone mineral distribution from DXA scans can serve as a valuable tool in enhancing the prediction of hip fractures for postmenopausal women in addition to BMD measurements. PMID:25683520

  9. Revised pediatric reference data for the lateral distal femur measured by Hologic Discovery/Delphi dual-energy X-ray absorptiometry.

    PubMed

    Zemel, Babette S; Stallings, Virginia A; Leonard, Mary B; Paulhamus, Donna R; Kecskemethy, Heidi H; Harcke, H Theodore; Henderson, Richard C

    2009-01-01

    Lateral distal femur (LDF) scans by dual-energy X-ray absorptiometry (DXA) are often feasible in children for whom other sites are not measurable. Pediatric reference data for LDF are not available for more recent DXA technology. The objective of this study was to assess older pediatric LDF reference data, construct new reference curves for LDF bone mineral density (BMD), and demonstrate the comparability of LDF BMD to other measures of BMD and strength assessed by DXA and by peripheral quantitative computed tomography (pQCT). LDF, spine and whole body scans of 821 healthy children, 5-18 yr of age, recruited at a single center were obtained using a Hologic Discovery/Delphi system (Hologic, Inc., Bedford, MA). Tibia trabecular and total BMD (3% site), cortical geometry (38% site) (cortical thickness, section modulus, and strain-strength index) were assessed by pQCT. Sex- and race-specific reference curves were generated using LMS Chartmaker (LMS Chartmaker Pro, version 2.3. Tim Cole and Huiqi Pan. Copyright 1997-2006, Medical Research Council, UK) and Z-scores calculated and compared by correlation analysis. Z-scores for LDF BMD based on published findings demonstrated overestimation or underestimation of the prevalence of low BMD-for-age depending on the region of interest considered. Revised LDF reference curves were generated. The new LDF Z-scores were strongly and significantly associated with weight, body mass index, spine and whole body BMD Z-scores, and all pQCT Z-scores. These findings demonstrate the comparability of LDF measurements to other clinical and research bone density assessment modes, and enable assessment of BMD in children with disabilities, who are particularly prone to low trauma fractures of long bones, and for whom traditional DXA measurement sites are not feasible. PMID:19321369

  10. Dual-energy X-ray absorptiometry, peripheral quantitative computed tomography, and micro-computed tomography techniques are discordant for bone density and geometry measurements in the guinea pig.

    PubMed

    Mak, Ivy L; DeGuire, Jason R; Lavery, Paula; Agellon, Sherry; Weiler, Hope A

    2016-05-01

    This study aims to examine agreement among bone mineral content (BMC) and density (BMD) estimates obtained using dual-energy X-ray absorptiometry (DXA), peripheral quantitative computed tomography (pQCT), and micro-computed tomography (μCT) against high-resolution μCT and bone ash of the guinea pig femur. Middle-aged (n = 40, 86 weeks) male guinea pigs underwent in vivo followed by ex vivo DXA (Hologic QDR 4500A) scanning for intact and excised femur BMC and areal density. To assess bone architecture and strength, excised femurs were scanned on pQCT (Stratec XCT 2000L) as well as on two μCT scanners (LaTheta LCT-200; Skyscan 1174), followed by three-point bending test. Reproducibility was determined using triplicate scans; and agreement assessed using Bland-Altman plots with reference methods being high-resolution μCT (Skyscan) for BMD and bone ashing for BMC. All techniques showed satisfactory ex vivo precision (CV 0.05-4.3 %). However, bias compared to the reference method was highest (207.5 %) in trabecular bone volume fraction (BV/TV) measured by LaTheta, and unacceptable in most total femur and cortical bone measurements. Volumetric BMD (vBMD) and BV/TV derived by LaTheta and pQCT at the distal metaphysis were biased from the Skyscan by an average of 49.3 and 207.5 %, respectively. Variability of vBMD, BV/TV and cross-sectional area at the diaphysis ranged from -5.5 to 30.8 %. LaTheta best quantified total femur BMC with an upper bias of 3.3 %. The observed differences among imaging techniques can be attributable to inherent dissimilarity in construction design, calibration, segmentation and scanning resolution used. These bone imaging tools are precise but are not comparable, at least when assessing guinea pig bones. PMID:26058491

  11. Ultrasound-Derived Forearm Muscle Thickness Is a Powerful Predictor for Estimating DXA-Derived Appendicular Lean Mass in Japanese Older Adults.

    PubMed

    Abe, Takashi; Fujita, Eiji; Thiebaud, Robert S; Loenneke, Jeremy P; Akamine, Takuya

    2016-09-01

    To test the validity of published equations, anterior forearm muscle thickness (MT-ulna) of 158 Japanese older adults (72 men and 86 women) aged 50-79 y was measured with ultrasound. Appendicular lean soft tissue mass (aLM) was estimated from MT-ulna using two equations (body height without [eqn 1] and with [eqn 2]) previously published in the literature. Appendicular lean mass was measured using dual-energy X-ray absorption (DXA), and this method served as the reference criterion. There was a strong correlation between DXA-derived and ultrasound-estimated aLM in both equations (r = 0.882 and r = 0.944). Total error was 2.60 kg for eqn (1) and 1.38 kg for eqn (2). A Bland-Altman plot revealed that there was no systematic bias between DXA-derived and ultrasound-estimated aLM; however, eqn (1) overestimated aLM compared with DXA-derived aLM. Our results suggest that an ultrasound MT-ulna equation that includes body height is appropriate and useful for estimating aLM in Japanese adults. PMID:27321173

  12. Estimation of the sensitivity in dual wave X-ray absorptiometry

    NASA Astrophysics Data System (ADS)

    Gogolev, A.; Rezaev, R.; Cherepennikov, Yu; Vukolov, A.; Gogoleva, T.

    2016-07-01

    Dual wave X-ray absorptiometry is considered theoretically and the application of suggested technique extends to the multiphase flow analysis. Proposed method allows for specifying dynamically the percentage of fluid components with the resolution as high as 0.25% (according to the mathematical simulating). The accuracy of this measurement is one order higher by magnitude than that provided by the state of the art flow analyzing devices.

  13. Associations Between Sedentary Time, Physical Activity, and Dual-Energy X-ray Absorptiometry Measures of Total Body, Android, and Gynoid Fat Mass in Children.

    PubMed

    McCormack, Lacey; Meendering, Jessica; Specker, Bonny; Binkley, Teresa

    2016-01-01

    Negative health outcomes are associated with excess body fat, low levels of physical activity (PA), and high sedentary time (ST). Relationships between PA, ST, and body fat distribution, including android and gynoid fat, assessed using dual-energy X-ray absorptiometry (DXA) have not been measured in children. The purpose of this study was to test associations between levels of activity and body composition in children and to evaluate if levels of activity predict body composition by DXA and by body mass index percentile in a similar manner. PA, ST, and body composition from 87 children (8.8-11.8 yr, grades 3-5, 44 boys) were used to test the association among study variables. Accelerometers measured PA and ST. Body composition measured by DXA included bone mineral content (BMC) and fat and lean mass of the total body (TB, less head), android, and gynoid regions. ST (range: 409-685 min/wk) was positively associated with TB percent fat (0.03, 95% confidence interval [CI]: 0.00-0.05) and android fat mass (1.5 g, 95% CI: 0.4-3.0), and inversely associated with the lean mass of the TB (-10.7 g, 95% CI: -20.8 to -0.63) and gynoid regions (-2.2 g, 95% CI: -4.3 to -0.2), and with BMC (-0.43 g, 95% CI: 0.77-0.09). Moderate-to-vigorous PA was associated with lower TB (-53 g, 95% CI: -87 to -18), android (-5 g, 95% CI: -8 to -2]), and gynoid fat (-6 g, 95% CI: -11 to -0.5). Vigorous activity results were similar. Light PA was associated with increased TB (17.1 g, 95% CI: 3.0-31.3) and gynoid lean mass (3.9 g, 95% CI: 1.0-6.8) and BMC (0.59 g, 95% CI: 0.10-1.07). In boys, there were significant associations between activity and DXA percent body fat measures that were not found with the body mass index percentile. Objective measures of PA were inversely associated with TB, android, and gynoid fat, whereas ST was directly associated with TB percent fat and, in particular, android fat. Activity levels predict body composition measures by DXA and, in

  14. A DXA Whole Body Composition Cross-Calibration Experience: Evaluation With Humans, Spine, and Whole Body Phantoms.

    PubMed

    Krueger, Diane; Libber, Jessie; Sanfilippo, Jennifer; Yu, Hui Jing; Horvath, Blaine; Miller, Colin G; Binkley, Neil

    2016-01-01

    New densitometer installation requires cross-calibration for accurate longitudinal assessment. When replacing a unit with the same model, the International Society for Clinical Densitometry recommends cross-calibrating by scanning phantoms 10 times on each instrument and states that spine bone mineral density (BMD) should be within 1%, whereas total body lean, fat, and %fat mass should be within 2% of the prior instrument. However, there is limited validation that these recommendations provide adequate total body cross-calibration. Here, we report a total body cross-calibration experience with phantoms and humans. Cross-calibration between an existing and new Lunar iDXA was performed using 3 encapsulated spine phantoms (GE [GE Lunar, Madison, WI], BioClinica [BioClinica Inc, Princeton, NJ], and Hologic [Hologic Inc, Bedford, MA]), 1 total body composition phantom (BioClinica), and 30 human volunteers. Thirty scans of each phantom and a total body scan of human volunteers were obtained on each instrument. All spine phantom BMD means were similar (within 1%; <-0.010 g/cm2 bias) between the existing and new dual-energy X-ray absorptiometry unit. The BioClinica body composition phantom (BBCP) BMD and bone mineral content (BMC) values were within 2% with biases of 0.005 g/cm2 and -3.4 g. However, lean and fat mass and %fat differed by 4.6%-7.7% with biases of +463 g, -496 g, and -2.8%, respectively. In vivo comparison supported BBCP data; BMD and BMC were within ∼2%, but lean and fat mass and %fat differed from 1.6% to 4.9% with biases of +833 g, -860 g, and -1.1%. As all body composition comparisons exceeded the recommended 2%, the new densitometer was recalibrated. After recalibration, in vivo bias was lower (<0.05%) for lean and fat; -23 and -5 g, respectively. Similarly, BBCP lean and fat agreement improved. In conclusion, the BBCP behaves similarly, but not identical, to human in vivo measurements for densitometer cross-calibration. Spine phantoms, despite good

  15. Measurement of the subcutaneous fat in the distal forearm by single photon absorptiometry

    SciTech Connect

    Hassager, C.; Borg, J.; Christiansen, C.

    1989-02-01

    The influence of subcutaneous fat on single photon (/sup 125/I) absorptiometry (SPA) measurement of bone mineral content of the distal forearm was investigated. A fat correction model was tested by measurements on eight lean subjects with different amounts of porcine fat around their forearm, and further validated from measurements on 128 females. In addition, it is shown that the fat content in the distal forearm can be measured by SPA with a short-term precision at 1.9% in an obese subject and that it correlates well with total body fat (r2 = .7) measured by dual photon absorptiometry, skinfold thickness (r2 = .5), and body mass index (r2 = .6). By using this method in a double-blind placebo-controlled trial, hormonal substitutional therapy significantly decreased the forearm fat content without affecting the body weight in postmenopausal osteoporotic women.

  16. Ultrasound-Derived Abdominal Muscle Thickness Better Detects Metabolic Syndrome Risk in Obese Patients than Skeletal Muscle Index Measured by Dual-Energy X-Ray Absorptiometry.

    PubMed

    Ido, Ayumi; Nakayama, Yuki; Ishii, Kojiro; Iemitsu, Motoyuki; Sato, Koji; Fujimoto, Masahiro; Kurihara, Toshiyuki; Hamaoka, Takafumi; Satoh-Asahara, Noriko; Sanada, Kiyoshi

    2015-01-01

    Sarcopenia has never been diagnosed based on site-specific muscle loss, and little is known about the relationship between site-specific muscle loss and metabolic syndrome (MetS) risk factors. To this end, this cross-sectional study aimed to investigate the relationship between site-specific muscle size and MetS risk factors. Subjects were 38 obese men and women aged 40-82 years. Total body fat and lean body mass were assessed by whole-body dual-energy X-ray absorptiometry (DXA) scan. Muscle thickness (MTH) was measured using B-mode ultrasound scanning in six body regions. Subjects were classified into general obesity (GO) and sarcopenic obesity (SO) groups using the threshold values of one standard deviation below the sex-specific means of either MTH or skeletal muscle index (SMI) measured by DXA. MetS risk score was acquired by standardizing and summing the following continuously distributed variables: visceral fat area, mean blood pressure, HbA1c, and serum triglyceride / high density lipoprotein cholesterol, to obtain the Z-score. Multiple regression analysis revealed that the MetS risk score was independently associated with abdominal MTH in all subjects, but not with MTH in other muscle regions, including the thigh. Although HbA1c and the number of MetS risk factors in the SO group were significantly higher than those in the GO group, there were no significant differences between GO and SO groups as defined by SMI. Ultrasound-derived abdominal MTH would allow a better assessment of sarcopenia in obese patients and can be used as an alternative to the conventionally-used SMI measured by DXA. PMID:26700167

  17. Ultrasound-Derived Abdominal Muscle Thickness Better Detects Metabolic Syndrome Risk in Obese Patients than Skeletal Muscle Index Measured by Dual-Energy X-Ray Absorptiometry

    PubMed Central

    Ido, Ayumi; Nakayama, Yuki; Ishii, Kojiro; Iemitsu, Motoyuki; Sato, Koji; Fujimoto, Masahiro; Kurihara, Toshiyuki; Hamaoka, Takafumi; Satoh-Asahara, Noriko; Sanada, Kiyoshi

    2015-01-01

    Sarcopenia has never been diagnosed based on site-specific muscle loss, and little is known about the relationship between site-specific muscle loss and metabolic syndrome (MetS) risk factors. To this end, this cross-sectional study aimed to investigate the relationship between site-specific muscle size and MetS risk factors. Subjects were 38 obese men and women aged 40–82 years. Total body fat and lean body mass were assessed by whole-body dual-energy X-ray absorptiometry (DXA) scan. Muscle thickness (MTH) was measured using B-mode ultrasound scanning in six body regions. Subjects were classified into general obesity (GO) and sarcopenic obesity (SO) groups using the threshold values of one standard deviation below the sex-specific means of either MTH or skeletal muscle index (SMI) measured by DXA. MetS risk score was acquired by standardizing and summing the following continuously distributed variables: visceral fat area, mean blood pressure, HbA1c, and serum triglyceride / high density lipoprotein cholesterol, to obtain the Z-score. Multiple regression analysis revealed that the MetS risk score was independently associated with abdominal MTH in all subjects, but not with MTH in other muscle regions, including the thigh. Although HbA1c and the number of MetS risk factors in the SO group were significantly higher than those in the GO group, there were no significant differences between GO and SO groups as defined by SMI. Ultrasound-derived abdominal MTH would allow a better assessment of sarcopenia in obese patients and can be used as an alternative to the conventionally-used SMI measured by DXA. PMID:26700167

  18. Dual-Energy X-Ray Absorptiometry, Skinfold Thickness, and Waist Circumference for Assessing Body Composition in Ambulant and Non-Ambulant Wheelchair Games Players

    PubMed Central

    Willems, Annika; Paulson, Thomas A. W.; Keil, Mhairi; Brooke-Wavell, Katherine; Goosey-Tolfrey, Victoria L.

    2015-01-01

    Field-based assessments provide a cost–effective and accessible alternative to dual-energy X-ray absorptiometry (DXA) for practitioners determining body composition in athletic populations. It remains unclear how the range of physical impairments classifiable in wheelchair sports may affect the utility of field-based body composition techniques. The present study assessed body composition using DXA in 14 wheelchair games players who were either wheelchair dependent (non-walkers; n = 7) or relied on a wheelchair for sports participation only (walkers; n = 7). Anthropometric measurements were used to predict body fat percentage with existing regression equations established for able-bodied persons by Sloan and Weir, Durnin and Womersley, Lean et al, Gallagher et al, and Pongchaiyakul et al. In addition, linear regression analysis was performed to calculate the association between body fat percentage and BMI, waist circumference, sum of 6 skinfold thickness and sum of 8 skinfold thickness. Results showed that non-walkers had significantly lower total lean tissue mass (46.2 ± 6.6 kg vs. 59.4 ± 8.2 kg, P = 0.006) and total body mass (65.8 ± 4.2 kg vs. 79.4 ± 14.9 kg; P = 0.05) than walkers. Body fat percentage calculated from most existing regression equations was significantly lower than that from DXA, by 2 to 9% in walkers and 8 to 14% in non-walkers. Of the anthropometric measurements, the sum of 8 skinfold thickness had the lowest standard error of estimation in predicting body fat content. In conclusion, existing anthropometric equations developed in able-bodied populations substantially underestimated body fat content in wheelchair athletes, particularly non-walkers. Impairment specific equations may be needed in wheelchair athletes. PMID:26640442

  19. Measurement of bone mineral content in vivo using photon absorptiometry

    PubMed Central

    Boyd, R. M.; Cameron, E. C.; McIntosh, H. W.; Walker, V. R.

    1974-01-01

    Progress in evaluating treatment of systemic bone disease has been hampered in the past by lack of precise in vivo quantitative techniques. Recently a method has been developed for measurement of bone mineral content (BMC), based on bone absorption of low-energy monochromatic radiation. This paper discusses a technique of photon absorptiometry using 125l as a collimated point source. The technique is simple, with accuracy and precision within 2%. BMC and bone width (W) were measured in the distal radius of 359 normal subjects ranging in age from 5 to 82 years. A “normal” curve of BMC/W with age as the independent variable was then obtained from this population and was constructed for each sex. A positive correlation of BMC/W with height and body weight was found in a group of normal males. A series of patients with osteoporosis or malabsorption, or undergoing hemodialysis or steroid treatment, was then assessed in order to demonstrate changes in BMC/W that may occur secondary to disease or disturbances in calcium metabolism. Many of these patients were found to have a BMC/W below the normal mean value for their age and sex. PMID:4434288

  20. The relationship between fractures and DXA measures of BMD in the distal femur of children and adolescents with cerebral palsy or muscular dystrophy.

    PubMed

    Henderson, Richard C; Berglund, Lisa M; May, Ryan; Zemel, Babette S; Grossberg, Richard I; Johnson, Julie; Plotkin, Horacio; Stevenson, Richard D; Szalay, Elizabeth; Wong, Brenda; Kecskemethy, Heidi H; Harcke, H Theodore

    2010-03-01

    Children with limited or no ability to ambulate frequently sustain fragility fractures. Joint contractures, scoliosis, hip dysplasia, and metallic implants often prevent reliable measures of bone mineral density (BMD) in the proximal femur and lumbar spine, where BMD is commonly measured. Further, the relevance of lumbar spine BMD to fracture risk in this population is questionable. In an effort to obtain bone density measures that are both technically feasible and clinically relevant, a technique was developed involving dual-energy X-ray absorptiometry (DXA) measures of the distal femur projected in the lateral plane. The purpose of this study is to test the hypothesis that these new measures of BMD correlate with fractures in children with limited or no ability to ambulate. The relationship between distal femur BMD Z-scores and fracture history was assessed in a cross-sectional study of 619 children aged 6 to 18 years with muscular dystrophy or moderate to severe cerebral palsy compiled from eight centers. There was a strong correlation between fracture history and BMD Z-scores in the distal femur; 35% to 42% of those with BMD Z-scores less than -5 had fractured compared with 13% to 15% of those with BMD Z-scores greater than -1. Risk ratios were 1.06 to 1.15 (95% confidence interval 1.04-1.22), meaning a 6% to 15% increased risk of fracture with each 1.0 decrease in BMD Z-score. In clinical practice, DXA measure of BMD in the distal femur is the technique of choice for the assessment of children with impaired mobility. PMID:19821773

  1. The Relationship Between Fractures and DXA Measures of BMD in the Distal Femur of Children and Adolescents With Cerebral Palsy or Muscular Dystrophy

    PubMed Central

    Henderson, Richard C; Berglund, Lisa M; May, Ryan; Zemel, Babette S; Grossberg, Richard I; Johnson, Julie; Plotkin, Horacio; Stevenson, Richard D; Szalay, Elizabeth; Wong, Brenda; Kecskemethy, Heidi H; Harcke, H Theodore

    2010-01-01

    Children with limited or no ability to ambulate frequently sustain fragility fractures. Joint contractures, scoliosis, hip dysplasia, and metallic implants often prevent reliable measures of bone mineral density (BMD) in the proximal femur and lumbar spine, where BMD is commonly measured. Further, the relevance of lumbar spine BMD to fracture risk in this population is questionable. In an effort to obtain bone density measures that are both technically feasible and clinically relevant, a technique was developed involving dual-energy X-ray absorptiometry (DXA) measures of the distal femur projected in the lateral plane. The purpose of this study is to test the hypothesis that these new measures of BMD correlate with fractures in children with limited or no ability to ambulate. The relationship between distal femur BMD Z-scores and fracture history was assessed in a cross-sectional study of 619 children aged 6 to 18 years with muscular dystrophy or moderate to severe cerebral palsy compiled from eight centers. There was a strong correlation between fracture history and BMD Z-scores in the distal femur; 35% to 42% of those with BMD Z-scores less than −5 had fractured compared with 13% to 15% of those with BMD Z-scores greater than −1. Risk ratios were 1.06 to 1.15 (95% confidence interval 1.04–1.22), meaning a 6% to 15% increased risk of fracture with each 1.0 decrease in BMD Z-score. In clinical practice, DXA measure of BMD in the distal femur is the technique of choice for the assessment of children with impaired mobility. © 2010 American Society for Bone and Mineral Research PMID:19821773

  2. Treatment of subclinical hypothyroidism does not affect bone mass as determined by dual-energy X-ray absorptiometry, peripheral quantitative computed tomography and quantitative bone ultrasound in Spanish women

    PubMed Central

    Roncero-Martin, Raul; Calderon-Garcia, Julian F.; Santos-Vivas, Mercedes; Vera, Vicente; Martínez-Alvárez, Mariana; Rey-Sanchez, Purificación

    2015-01-01

    Introduction The results of studies examining the influence of subclinical hypothyroidism (SCH) and levothyroxine (L-T4) replacement therapy on bone have generated considerable interest but also controversy. The present research aims to evaluate the effects of L-T4 treatment on different skeletal sites in women. Material and methods A group of 45 premenopausal (mean age: 43.62 ±6.65 years) and 180 postmenopausal (mean age: 59.51 ±7.90 years) women with SCH who were undergoing L-T4 replacement therapy for at least 6 months were compared to 58 pre- and 180 postmenopausal women with SCH (untreated) matched for age. The mean doses of L-T4 were 90.88 ±42.59 µg/day in the premenopausal women and 86.35 ±34.11 µg/day in the postmenopausal women. Bone measurements were obtained using quantitative bone ultrasound (QUS) for the phalanx, dual-energy X-ray absorptiometry (DXA) for the lumbar spine and hip, and peripheral quantitative computed tomography (pQCT) for the non-dominant distal forearm. Results No differences were observed between patients and untreated controls in these bone measurements except in the bone mineral density (BMD) of the spine (p = 0.0214) in postmenopausal women, which was greater in treated women than in untreated controls. Conclusions Our results indicate that adequate metabolic control through replacement treatment with L-T4 in pre- and postmenopausal women does not affect bone mass. PMID:26528344

  3. Body composition analysis of inter-county Gaelic athletic association players measured by dual energy X-ray absorptiometry.

    PubMed

    Davies, Robert W; Toomey, Clodagh; McCormack, William; Hughes, Katie; Cremona, Alexandra; Jakeman, Philip

    2016-06-01

    Gaelic Football and Hurling are two sporting codes within the Gaelic Athletic Association. The purpose of this study was to report the body composition phenotype of inter-county Gaelic athletic association players, comparing groups by code and field position. 190 senior, male, outfield inter-county players (144 hurlers and 46 Gaelic footballers) were recruited. Stature and body mass was measured, estimates of three components of body composition, i.e. lean mass, fat mass and bone mineral content was obtained by dual energy X-ray absorptiometry (DXA), and normative data for Gaelic athletic association athletes by code and position was compared. Other than in the midfield, there was limited difference in body composition between codes or playing position. Stature-corrected indices nullified any existing group differences between midfielders for both codes. Further comparisons with a non-athletic control group (n = 431) showed no difference for body mass index (BMI); however, the athletic group has a lower fat mass index, with a greater lean mass in accounting for the matched BMI between groups. In addition to providing previously unknown normative data for the Gaelic athletic association athlete, a proportional and independent tissue evaluation of body composition is given. PMID:26343788

  4. Prediction of Hip Failure Load: In Vitro Study of 80 Femurs Using Three Imaging Methods and Finite Element Models-The European Fracture Study (EFFECT).

    PubMed

    Pottecher, Pierre; Engelke, Klaus; Duchemin, Laure; Museyko, Oleg; Moser, Thomas; Mitton, David; Vicaut, Eric; Adams, Judith; Skalli, Wafa; Laredo, Jean Denis; Bousson, Valérie

    2016-09-01

    Purpose To evaluate the performance of three imaging methods (radiography, dual-energy x-ray absorptiometry [DXA], and quantitative computed tomography [CT]) and that of a numerical analysis with finite element modeling (FEM) in the prediction of failure load of the proximal femur and to identify the best densitometric or geometric predictors of hip failure load. Materials and Methods Institutional review board approval was obtained. A total of 40 pairs of excised cadaver femurs (mean patient age at time of death, 82 years ± 12 [standard deviation]) were examined with (a) radiography to measure geometric parameters (lengths, angles, and cortical thicknesses), (b) DXA (reference standard) to determine areal bone mineral densities (BMDs), and (c) quantitative CT with dedicated three-dimensional analysis software to determine volumetric BMDs and geometric parameters (neck axis length, cortical thicknesses, volumes, and moments of inertia), and (d) quantitative CT-based FEM to calculate a numerical value of failure load. The 80 femurs were fractured via mechanical testing, with random assignment of one femur from each pair to the single-limb stance configuration (hereafter, stance configuration) and assignment of the paired femur to the sideways fall configuration (hereafter, side configuration). Descriptive statistics, univariate correlations, and stepwise regression models were obtained for each imaging method and for FEM to enable us to predict failure load in both configurations. Results Statistics reported are for stance and side configurations, respectively. For radiography, the strongest correlation with mechanical failure load was obtained by using a geometric parameter combined with a cortical thickness (r(2) = 0.66, P < .001; r(2) = 0.65, P < .001). For DXA, the strongest correlation with mechanical failure load was obtained by using total BMD (r(2) = 0.73, P < .001) and trochanteric BMD (r(2) = 0.80, P < .001). For quantitative CT, in both configurations

  5. Predicting Bone Mechanical Properties of Cancellous Bone from DXA, MRI, and Fractal Dimensional Measurements

    NASA Technical Reports Server (NTRS)

    Harrigan, Timothy P.; Ambrose, Catherine G.; Hogan, Harry A.; Shackleford, Linda; Webster, Laurie; LeBlanc, Adrian; Lin, Chen; Evans, Harlan

    1997-01-01

    This project was aimed at making predictions of bone mechanical properties from non-invasive DXA and MRI measurements. Given the bone mechanical properties, stress calculations can be made to compare normal bone stresses to the stresses developed in exercise countermeasures against bone loss during space flight. These calculations in turn will be used to assess whether mechanical factors can explain bone loss in space. In this study we assessed the use of T2(sup *) MRI imaging, DXA, and fractal dimensional analysis to predict strength and stiffness in cancellous bone.

  6. Total body composition by dual-photon (153Gd) absorptiometry

    SciTech Connect

    Mazess, R.B.; Peppler, W.W.; Gibbons, M.

    1984-10-01

    The lean-fat composition (%FATR) of soft tissue and the mineral mass of the skeleton were determined in vivo using dual-photon (153Gd) absorptiometry (dose under 2 mrem). A rectilinear raster scan was made over the entire body in 18 subjects (14 female, 4 male). Single-photon absorptiometry (125I) measured bone mineral content on the radius. Percentage fat (%FATD) was determined in the same subjects using body density (from underwater weighing with correction for residual lung volume). Lean body mass (LBM) was determined using both %FATR and %FATD. Percentage fat from absorptiometry and from underwater density were correlated (r . 0.87). The deviation of %FATD from %FATR was due to the amount of skeletal mineral as a percentage of the LBM (r . 0.90). Therefore, skeletal variability, even in normal subjects, where mineral ranges only from 4 to 8% of the LBM, essentially precludes use of body density as a composition indicator unless skeletal mass is measured. Anthropometry (fatfolds and weight) predicted %FATR and LBM at least as well as did underwater density. The predictive error of %FATR from fatfolds was 5% while the predictive error in predicting LBM from anthropometry was 2 to 3 kg (3%).

  7. Population-based geographic variations in DXA bone density in Europe: the EVOS Study. European Vertebral Osteoporosis.

    PubMed

    Lunt, M; Felsenberg, D; Adams, J; Benevolenskaya, L; Cannata, J; Dequeker, J; Dodenhof, C; Falch, J A; Johnell, O; Khaw, K T; Masaryk, P; Pols, H; Poor, G; Reid, D; Scheidt-Nave, C; Weber, K; Silman, A J; Reeve, J

    1997-01-01

    The purpose of this study was to investigate variations in bone density between 16 European populations, 13 of which were participants in the European Vertebral Osteoporosis Study (EVOS). Men and women aged 50-80 years were recruited randomly from local population registers, stratified in 5-year age bands. The other three centres recruited similarly. Random samples of 20-100% of EVOS subjects were invited for dual-energy X-ray absorptiometry (DXA) densitometry of the lumbar spine and/or proximal femur using Hologic, Lunar or Norland pencil beam machines or, in one centre, a Sopha fan-beam machine. Cross-calibration of the different machines was undertaken using the European Spine Phantom prototype (ESPp). Highly significant differences in mean bone density were demonstrated between centres, giving rise to between centre SDs in bone density that were about a quarter of a population SD. These differences persisted when centres using Hologic machines and centres using Lunar machines were considered separately. The centres were ranked differently according to whether male or female subjects were being considered and according to site of measurement (L2-4, femoral neck or femoral trochanter). As expected, bone mineral density (BMD) had a curvilinear relationship with age, and apparent rates of decrease slowed as age advanced past 50 years in both sexes. In the spine, not only did male BMD usually appear to increase with age, but there was a highly significant difference between centres in the age effect in both sexes, suggesting a variability in the impact of osteoarthritis between centres. Weight was consistently positively associated with BMD, but the effects of height and armspan were less consistent. Logarithmic transformation was needed to normalize the regressions of BMD on the independent variates, and after transformation, all sites except the femoral neck in females showed significant increases in SD with age. Interestingly, the effect of increasing weight was

  8. Estimating the Absorbed Dose to Critical Organs During Dual X-ray Absorptiometry

    PubMed Central

    Sharafi, A A; Larijani, B; Mokhlesian, N; Hasanzadeh, H

    2008-01-01

    Objective The purpose of this study is to estimate a patient's organ dose (effective dose) during performance of dual X-ray absorptiometry by using the correlations derived from the surface dose and the depth doses in an anthropomorphic phantom. Materials and Methods An anthropomorphic phantom was designed and TLDs (Thermoluminescent Dosimeters) were placed at the surface and these were also inserted at different depths of the thyroid and uterus of the anthropomorphic phantom. The absorbed doses were measured on the phantom for the spine and femur scan modes. The correlation coefficients and regression functions between the absorbed surface dose and the depth dose were determined. The derived correlation was then applied for 40 women patients to estimate the depth doses to the thyroid and uterus. Results There was a correlation between the surface dose and depth dose of the thyroid and uterus in both scan modes. For the women's dosimetry, the average surface doses of the thyroid and uterus were 1.88 µGy and 1.81 µGy, respectively. Also, the scan center dose in the women was 5.70 µGy. There was correlation between the thyroid and uterus surface doses, and the scan center dose. Conclusion We concluded that the effective dose to the patient's critical organs during dual X-ray absorptiometry can be estimated by the correlation derived from phantom dosimetry. PMID:18385556

  9. Cross-mode bioelectrical impedance analysis in a standing position for estimating fat-free mass validated against dual-energy x-ray absorptiometry.

    PubMed

    Huang, Ai-Chun; Chen, Yu-Yawn; Chuang, Chih-Lin; Chiang, Li-Ming; Lu, Hsueh-Kuan; Lin, Hung-Chi; Chen, Kuen-Tsann; Hsiao, An-Chi; Hsieh, Kuen-Chang

    2015-11-01

    Bioelectrical impedance analysis (BIA) is commonly used to assess body composition. Cross-mode (left hand to right foot, Z(CR)) BIA presumably uses the longest current path in the human body, which may generate better results when estimating fat-free mass (FFM). We compared the cross-mode with the hand-to-foot mode (right hand to right foot, Z(HF)) using dual-energy x-ray absorptiometry (DXA) as the reference. We hypothesized that when comparing anthropometric parameters using stepwise regression analysis, the impedance value from the cross-mode analysis would have better prediction accuracy than that from the hand-to-foot mode analysis. We studied 264 men and 232 women (mean ages, 32.19 ± 14.95 and 34.51 ± 14.96 years, respectively; mean body mass indexes, 24.54 ± 3.74 and 23.44 ± 4.61 kg/m2, respectively). The DXA-measured FFMs in men and women were 58.85 ± 8.15 and 40.48 ± 5.64 kg, respectively. Multiple stepwise linear regression analyses were performed to construct sex-specific FFM equations. The correlations of FFM measured by DXA vs. FFM from hand-to-foot mode and estimated FFM by cross-mode were 0.85 and 0.86 in women, with standard errors of estimate of 2.96 and 2.92 kg, respectively. In men, they were 0.91 and 0.91, with standard errors of the estimates of 3.34 and 3.48 kg, respectively. Bland-Altman plots showed limits of agreement of -6.78 to 6.78 kg for FFM from hand-to-foot mode and -7.06 to 7.06 kg for estimated FFM by cross-mode for men, and -5.91 to 5.91 and -5.84 to 5.84 kg, respectively, for women. Paired t tests showed no significant differences between the 2 modes (P > .05). Hence, cross-mode BIA appears to represent a reasonable and practical application for assessing FFM in Chinese populations. PMID:26409342

  10. Comparison of Speed of Sound Measures Assessed by Multisite Quantitative Ultrasound to Bone Mineral Density Measures Assessed by Dual-Energy X-Ray Absorptiometry in a Large Canadian Cohort: the Canadian Multicentre Osteoporosis Study (CaMos).

    PubMed

    Olszynski, Wojciech P; Adachi, Jonathon D; Hanley, David A; Davison, Kenneth S; Brown, Jacques P

    2016-01-01

    Dual-energy X-ray absorptiometry (DXA) is an important tool for the estimate of fracture risk through the measurement of bone mineral density (BMD). Similarly, multisite quantitate ultrasound can prospectively predict future fracture through the measurement of speed of sound (SOS). This investigation compared BMD (at the femoral neck, total hip, and lumbar spine) and SOS measures (at the distal radius, tibia, and phalanx sites) in a large sample of randomly-selected and community-based individuals from the Canadian Multicentre Osteoporosis Study. Furthermore, mass, height, and age were also compared with both measures. There were 4123 patients included with an age range of 30-96.8 yr. Pearson product moment correlations between BMD and SOS measures were low (0.21-0.29; all p<0.001), irrespective of site. Mass was moderately correlated with BMD measures (0.40-0.58; p<0.001), but lowly correlated with SOS measures (0.03-0.13; p<0.05). BMD and SOS were negatively correlated to age (-0.17 to -0.44; p<0.001). When regression analyses were performed to predict SOS measures at the 3 sites, the models predicted 20%-23% of the variance, leaving 77%-80% unaccounted for. The SOS measures in this study were found to be largely independent from BMD measures. In areas with no or limited access to DXA, the multisite quantitative ultrasound may act as a valuable tool to assess fracture risk. In locales with liberal access to DXA, the addition of SOS to BMD and other clinical risk factors may improve the identification of those patients at high risk for future fracture. PMID:26050876

  11. Body composition assessment of English Premier League soccer players: a comparative DXA analysis of first team, U21 and U18 squads.

    PubMed

    Milsom, Jordan; Naughton, Robert; O'Boyle, Andy; Iqbal, Zafar; Morgans, Ryland; Drust, Barry; Morton, James P

    2015-01-01

    Professional soccer players from the first team (1st team, n = 27), under twenty-one (U21, n = 21) and under eighteen (U18, n = 35) squads of an English Premier League soccer team were assessed for whole body and regional estimates of body composition using dual-energy X-ray absorptiometry (DXA). Per cent body fat was lower in 1st team (10.0 ± 1.6) compared with both U21 (11.6 ± 2.5, P = 0.02) and U18 (11.4 ± 2.6, P = 0.01) players. However, this difference was not due to variations (P = 0.23) in fat mass between squads (7.8 ± 1.6 v. 8.8 ± 2.1 v. 8.2 ± 2.4 kg, respectively) but rather the presence of more lean mass in 1st team (66.9 ± 7.1 kg, P < 0.01) and U21 (64.6 ± 6.5 kg, P = 0.02) compared with U18 (60.6 ± 6.3 kg) players. Accordingly, fat mass index was not different (P = 0.138) between squads, whereas lean mass index was greater (P < 0.01) in 1st team players (20.0 ± 1.1 kg · m(-2)) compared with U18 players (18.8 ± 1.4 kg · m(-2)). Differences in lean mass were also reflective of higher lean tissue mass in all regions, for example, upper limbs/lower limbs and trunk. Data suggest that training and nutritional interventions for younger players should therefore be targeted to lean mass growth as opposed to body fat loss. PMID:25686107

  12. Comparison of single- and dual-photon absorptiometry in postmenopausal bone mineral loss

    SciTech Connect

    Nilas, L.; Borg, J.; Gotfredsen, A.; Christiansen, C.

    1985-11-01

    The authors describe a single photon absorptiometric (SPA) technique, which enables differential estimation of the rates of loss from trabecular and cortical bone. Ten scans are obtained in the forearm: six in an area with about 7% trabecular bone and four scans in the adjacent distal area with a trabecular bone content of 25%. By comparing bone masses of these two sites in 19 postmenopausal and 53 premenopausal women, the postmenopausal trabecular bone loss was estimated to be approximately seven times greater than cortical loss within the first years of cessation of regular vaginal bleeding. On a group basis the bone loss at the distal forearm scan site (by SPA) corresponded closely to the spinal bone loss (by dual-photon absorptiometry). The reproducibility of the two scan sites in the forearm was 1-1.5% (CV%), which makes the method suitable for longitudinal studies. Corrections for variations in fatty tissue covering can be made without deterioration of the reproducibility.

  13. Bone mineral measurements: a comparison of delayed gamma neutron activation, dual-energy X-ray absorptiometry and direct chemical analysis.

    PubMed

    Economos, C D; Nelson, M E; Fiatarone Singh, M A; Kehayias, J J; Dallal, G E; Heymsfield, S B; Wang, J; Yasumura, S; Ma, R; Pierson, R N

    1999-01-01

    A system in vitro consisting of a femur from a cadaver and soft-tissue equivalent material was used to test the agreement between several techniques for measuring bone mineral. Calcium values measured by delayed gamma neutron activation (DGNA) and bone mineral content (BMC) by Lunar, Hologic and Norland dual-energy X-ray absorptiometers (DXA) were compared with calcium and ash content determined by direct chemical analysis. To assess the effect of soft-tissue thickness on measurements of bone mineral, we had three phantom configurations ranging from 15.0 to 26.0 cm in thickness, achieved by using soft-tissue equivalent overlays. Chemical analysis of the femur gave calcium and ash content values of 61.83 g +/- 0.51 g and 154.120 +/- 0.004 g, respectively. Calcium measured by DGNA did not differ from the ashed amount of calcium at any of the phantom configurations. The BMC measured by DXA was significantly higher, by 3-5%, than the amount determined by chemical analysis for the Lunar densitometer and significantly lower, by 3-6%, for the Norland densitometer (p<0.001-0.024), but only 1% lower (not significant) for the Hologic densitometer. DXA instruments showed a decreasing trend in BMC as the thickness increased from 20.5 to 26.0 cm (p<0.05). However, within the entire thickness range (15.0-26.0 cm), the overall influence of thickness on BMC by DXA was very small. These findings offer insight into the differences in these currently available methods for bone mineral measurement and challenge the comparability of different methods. PMID:10525711

  14. Comparison of Body Composition Assessment Methods in Pediatric Intestinal Failure

    PubMed Central

    Mehta, Nilesh M.; Raphael, Bram; Guteirrez, Ivan; Quinn, Nicolle; Mitchell, Paul D.; Litman, Heather J.; Jaksic, Tom; Duggan, Christopher P.

    2015-01-01

    Objectives To examine the agreement of multifrequency bioelectric impedance analysis (BIA) and anthropometry with reference methods for body composition assessment in children with intestinal failure (IF). Methods We conducted a prospective pilot study in children 14 years of age or younger with IF resulting from either short bowel syndrome (SBS) or motility disorders. Bland Altman analysis was used to examine the agreement between BIA and deuterium dilution in measuring total body water (TBW) and lean body mass (LBM); and between BIA and dual X-ray absorptiometry (DXA) techniques in measuring LBM and FM. Fat mass (FM) and percent body fat (%BF) measurements by BIA and anthropometry, were also compared in relation to those measured by deuterium dilution. Results Fifteen children with IF, median (IQR) age 7.2 (5.0, 10.0) years, 10 (67%) male, were studied. BIA and deuterium dilution were in good agreement with a mean bias (limits of agreement) of 0.9 (-3.2, 5.0) for TBW (L) and 0.1 (-5.4 to 5.6) for LBM (kg) measurements. The mean bias (limits) for FM (kg) and %BF measurements were 0.4 (-3.8, 4.6) kg and 1.7 (-16.9, 20.3)% respectively. The limits of agreement were within 1 SD of the mean bias in 12/14 (86%) subjects for TBW and LBM, and in 11/14 (79%) for FM and %BF measurements. Mean bias (limits) for LBM (kg) and FM (kg) between BIA and DXA were 1.6 (-3.0 to 6.3) kg and -0.1 (-3.2 to 3.1) kg, respectively. Mean bias (limits) for FM (kg) and %BF between anthropometry and deuterium dilution were 0.2 (-4.2, 4.6) and -0.2 (-19.5 to 19.1), respectively. The limits of agreement were within 1 SD of the mean bias in 10/14 (71%) subjects. Conclusions In children with intestinal failure, TBW and LBM measurements by multifrequency BIA method were in agreement with isotope dilution and DXA methods, with small mean bias. In comparison to deuterium dilution, BIA was comparable to anthropometry for FM and %BF assessments with small mean bias. However, the limits of agreement

  15. Performance of calcaneus quantitative ultrasound and dual-energy X-ray absorptiometry in the discrimination of prevalent asymptomatic osteoporotic fractures in postmenopausal women.

    PubMed

    El Maghraoui, A; Morjane, F; Mounach, A; Ghazi, M; Nouijai, A; Achemlal, L; Bezza, A; Ghozlani, I

    2009-03-01

    Due to its low cost, portability, and nonionizing radiation, quantitative ultrasound (QUS) of the heel is an alternative to the measurement with dual X-ray absorptiometry (DXA) in the evaluation of bone status. The objective of the study is to compare in asymptomatic postmenopausal women the ability of QUS and DXA to discriminate between those with and without prevalent vertebral fractures (VFs). The study cohort consists of a population of 295 postmenopausal women aged between 60 and 84 (mean age, weight and BMI of 66.3 years, 72.0 kg and 29.4 kg/m(2), respectively). Lateral VFA images and scans of the lumbar spine and proximal femur were obtained by two technologists using a GE Healthcare Lunar Prodigy densitometer. VFs were defined using a combination of Genant semiquantitative (SQ) approach and morphometry. All women had a calcaneous QUS examination. The mean age of the women in our sample was 66.3 (+/-5.3) years, ranging from 60 to 84 years. Eighty-seven (29.3%) women had VFs Genant grade 2 and 3. Patients with VFs had an age and a number of years of menopause higher to those without VFs, but showed lower height, weight, and BMI. All densitometric and ultrasonometric measurements were significantly reduced in women with VFs. The intercorrelations of BMD at different sites were high, and the correlations of BUA with BMD were lower. BUA correlated weakly with total hip BMD (r = 0.36), lumbar spine BMD (r = 0.32), and much less with femur BMD (r = 0.30); all correlations were significant (P < 0.01). Analysis of the AUC for the ROC curves showed lumbar spine T-score below -2.5 to provide consistently the highest AUC (0.64). Age-adjusted ORs after correction for confounding variables (years of menopause, weight, height, and BMI) for QUS and BMD measurements showed that only lumbar spine T-score below -2.5 could predict significantly the presence of VFs (OR, 1.94; 95%CI, 1.02-3.41). Lumbar spine BMD (and not QUS) was able to discriminate asymptomatic postmenopausal

  16. Reproducibility of dual-photon absorptiometry using a clinical phantom

    SciTech Connect

    DaCosta, M.; DeLaney, M.; Goldsmith, S.J.

    1985-05-01

    The use of dual-photon absorptiometry (DPA) bone mineral density (BMD) to monitor bone for diagnosis and monitoring therapy of osteoporosis has been established. The objective of this study is to determine the reproducibility of DPA measurements. A phantom was constructed using a section of human boney pelvis and lumbo-sacral spine. Provisions were made to mimic changes in patient girth. To evaluate the DPA reproducibility within a single day, 12 consecutive studies were performed on the phantom using standard acquisition and processing procedures. The mean BMD +-1 SD in gms/cm/sup 2/ (BMD-bar)of lumbar vertebrae 2-4 was 0.771 +- 0.007 with a 0.97% coefficient of variation (1SD) (CV). This evaluation was repeated 7 times over the next 4 months with the performance of 3 to 6 studies each time, the maximum CV found was 1.93. In order to evaluate the DPA reproducibility with time, phantom studies were performed over a 7 month period which included a 153-Gd source change. The BMD-bar was 0.770 +- 0.017 with a 2.15CV. DPA reproducibility with patient girth changes was evaluated by performing the phantom studies at water depths of 12.5, 17.0 and 20.0cm. Five studies of each were performed using standard acquisition and processing procedures. The BMD-bar was 0.779 +- 0.012 with a 1.151CV. based on these results, BMD measurements by DPA are reproducible within 2%. This reliability is maintained for studies performed over extended period of time and are independent of changes in patient girth.

  17. Use of DXA-Based Structural Engineering Models of the Proximal Femur to Discriminate Hip Fracture

    PubMed Central

    Yang, Lang; Peel, Nicola; Clowes, Jackie A; McCloskey, Eugene V; Eastell, Richard

    2011-01-01

    Several DXA-based structural engineering models (SEMs) of the proximal femur have been developed to estimate stress caused by sideway falls. Their usefulness in discriminating hip fracture has not yet been established and we therefore evaluated these models. The hip DXA scans of 51 postmenopausal women with hip fracture (30 femoral neck, 17 trochanteric, and 4 unspecified) and 153 age-, height-, and weight-matched controls were reanalyzed using a special version of Hologic’s software that produced a pixel-by-pixel BMD map. For each map, a curved-beam, a curved composite-beam, and a finite element model were generated to calculate stress within the bone when falling sideways. An index of fracture risk (IFR) was defined over the femoral neck, trochanter, and total hip as the stress divided by the yield stress at each pixel and averaged over the regions of interest. Hip structure analysis (HSA) was also performed using Hologic APEX analysis software. Hip BMD and almost all parameters derived from HSA and SEM were discriminators of hip fracture on their own because their ORs were significantly >1. Because of the high correlation of total hip BMD to HSA and SEM-derived parameters, only the bone width discriminated hip fracture independently from total hip BMD. Judged by the area under the receiver operating characteristics curve, the trochanteric IFR derived from the finite element model was significant better than total hip BMD alone and similar to the total hip BMD plus bone width in discriminating all hip fracture and femoral neck fracture. No index was better than total hip BMD for discriminating trochanteric fractures. In conclusion, the finite element model has the potential to replace hip BMD in discriminating hip fractures. PMID:18767924

  18. Combining 3D optical imaging and dual energy absorptiometry to measure three compositional components

    NASA Astrophysics Data System (ADS)

    Malkov, Serghei; Shepherd, John

    2014-02-01

    We report on the design of the technique combining 3D optical imaging and dual-energy absorptiometry body scanning to estimate local body area compositions of three compartments. Dual-energy attenuation and body shape measures are used together to solve for the three compositional tissue thicknesses: water, lipid, and protein. We designed phantoms with tissue-like properties as our reference standards for calibration purposes. The calibration was created by fitting phantom values using non-linear regression of quadratic and truncated polynomials. Dual-energy measurements were performed on tissue-mimicking phantoms using a bone densitometer unit. The phantoms were made of materials shown to have similar x-ray attenuation properties of the biological compositional compartments. The components for the solid phantom were tested and their high energy/low energy attenuation ratios are in good correspondent to water, lipid, and protein for the densitometer x-ray region. The three-dimensional body shape was reconstructed from the depth maps generated by Microsoft Kinect for Windows. We used open-source Point Cloud Library and freeware software to produce dense point clouds. Accuracy and precision of compositional and thickness measures were calculated. The error contributions due to two modalities were estimated. The preliminary phantom composition and shape measurements are found to demonstrate the feasibility of the method proposed.

  19. Combining 3D optical imaging and dual energy absorptiometry to measure three compositional components

    PubMed Central

    Malkov, Serghei; Shepherd, John

    2014-01-01

    We report on the design of the technique combining 3D optical imaging and dual-energy absorptiometry body scanning to estimate local body area compositions of three compartments. Dual-energy attenuation and body shape measures are used together to solve for the three compositional tissue thicknesses: water, lipid, and protein. We designed phantoms with tissue-like properties as our reference standards for calibration purposes. The calibration was created by fitting phantom values using non-linear regression of quadratic and truncated polynomials. Dual-energy measurements were performed on tissue-mimicking phantoms using a bone densitometer unit. The phantoms were made of materials shown to have similar x-ray attenuation properties of the biological compositional compartments. The components for the solid phantom were tested and their high energy/low energy attenuation ratios are in good correspondent to water, lipid, and protein for the densitometer x-ray region. The three-dimensional body shape was reconstructed from the depth maps generated by Microsoft Kinect for Windows. We used open-source Point Cloud Library and freeware software to produce dense point clouds. Accuracy and precision of compositional and thickness measures were calculated. The error contributions due to two modalities were estimated. The preliminary phantom composition and shape measurements are found to demonstrate the feasibility of the method proposed. PMID:25083118

  20. Digital X-ray radiogrammetry in the study of osteoporotic fractures: Comparison to dual energy X-ray absorptiometry and FRAX.

    PubMed

    Kälvesten, Johan; Lui, Li-Yung; Brismar, Torkel; Cummings, Steven

    2016-05-01

    Osteoporosis is often underdiagnosed and undertreated. Screening of post-menopausal women for clinical risk factors and/or low bone mineral density (BMD) has been proposed to overcome this. Digital X-ray radiogrammetry (DXR) estimates hand BMD from standard hand X-ray images and have shown to predict fractures and osteoporosis. Recently, digital radiology and the internet have opened up the possibility of conducting automated opportunistic screening with DXR in post-fracture care or in combination with mammography. This study compared the performance of DXR with FRAX® and DXA in discriminating major osteoporotic fracture (MOF) (hip, clinical spine, forearm or shoulder), hip fracture and femoral neck osteoporosis. This prospective cohort study was conducted on 5278 women 65years and older in the Study of Osteoporotic Fractures (SOF) cohort. Baseline hand X-ray images were analyzed and fractures were ascertained during 10years of follow up. Age-adjusted area under receiver operating characteristic curve (AUC) for MOF and hip fracture and for femoral neck osteoporosis (DXA FN BMD T-score ≤-2.5) was used to compare the methods. Sensitivity to femoral neck osteoporosis at equal selection rates was tabulated for FRAX and DXR. DXR-BMD, FRAX (no BMD) and lumbar spine DXA BMD were all similar in fracture discriminative performance with an AUC around 0.65 for MOF and 0.70 for hip fractures for all three methods. As expected femoral neck DXA provided fracture discrimination superior both to other BMD measurements and to FRAX. AUC for selection of patients with femoral neck osteoporosis was higher with DXR-BMD, 0.76 (0.74-0.77), than with FRAX, 0.69 (0.67-0.71), (p<0.0001). In conclusion, DXR-BMD discriminates incident fractures to a similar degree as FRAX and predicts femoral neck osteoporosis to a larger degree than FRAX. DXR shows promise as a method to automatically flag individuals who might benefit from an osteoporosis assessment. PMID:26921822

  1. Photon absorptiometry for non-invasive measurement of bone mineral content

    SciTech Connect

    Gupta, S.; Luna, E.; Belsky, J.; Gelfman, N.; Miller, K.; Davies, T.

    1984-08-01

    Bone mineral content of the distal radius was determined in 106 patients by single photon absorptiometry using iodine-125 monochromatic source. The technique provided a reliable means to assess the degree of mineral loss in conditions such as osteoporosis, renal osteodystrophy in patients on chronic maintenance dialysis, subjects on long-term steroid therapy, and those with diabetes mellitus. It is more sensitive than conventional radiography and completely noninvasive compared to bone biopsy. It is suggested that photon absorptiometry is a simple, sensitive, and reliable technique for assessment and follow-up of the bone mineral content in a host of disorders associated with bone demineralization.

  2. Magnetic resonance imaging of the calcaneus: preliminary assessment of trabecular bone-dependent regional variations in marrow relaxation time compared with dual X-ray absorptiometry

    NASA Technical Reports Server (NTRS)

    Guglielmi, G.; Selby, K.; Blunt, B. A.; Jergas, M.; Newitt, D. C.; Genant, H. K.; Majumdar, S.

    1996-01-01

    RATIONALE AND OBJECTIVES: Marrow transverse relaxation time (T2*) in magnetic resonance (MR) imaging may be related to the density and structure of the surrounding trabecular network. We investigated regional variations of T2* in the human calcaneus and compared the findings with bone mineral density (BMD), as measured by dual X-ray absorpiometry (DXA). Short- and long-term precisions were evaluated first to determine whether MR imaging would be useful for the clinical assessment of disease status and progression in osteoporosis. METHODS: Gradient-recalled echo MR images of the calcaneus were acquired at 1.5 T from six volunteers. Measurements of T2* were compared with BMD and (for one volunteer) conventional radiography. RESULTS: T2* values showed significant regional variation; they typically were shortest in the superior region of the calcaneus. There was a linear correlation between MR and DXA measurements (r = .66 for 1/T2* versus BMD). Differences in T2* attributable to variations in analysis region-of-interest placement were not significant for five of the six volunteers. Sagittal MR images had short- and long-term precision errors of 4.2% and 3.3%, respectively. For DXA, the precision was 1.3% (coefficient of variation). CONCLUSION: MR imaging may be useful for trabecular bone assessment in the calcaneus. However, given the large regional variations in bone density and structure, the choice of an ROI is likely to play a major role in the accuracy, precision, and overall clinical efficacy of T2* measurements.

  3. Comparison of dual-energy x-ray absorptiometry and dual photon absorptiometry for bone mineral measurements of the lumbar spine

    SciTech Connect

    Wahner, H.W.; Dunn, W.L.; Brown, M.L.; Morin, R.L.; Riggs, B.L.

    1988-11-01

    A new x-ray-based (dual-energy x-ray absorptiometry (DEXA)) instrument for measurement of bone mineral in the spine and hips was compared with a commercial dual photon absorptiometry (DPA) instrument that uses a 153Gd source (DP3, Lunar Radiation Corporation). Measurements were made on phantoms and lumbar spines of patients to study accuracy, precision, limitations, and compatibility of results between instruments. Both instruments measure bone mineral of integral bone in terms of area bone density with an entrance exposure of less than 5 mR. For spinal bone mineral measurements, the DEXA instrument had a shorter scanning time and higher resolution images than the DPA system. The DEXA instrument also showed better precision in a spine phantom and reduced influence of thickness for patient measurement. For bone mineral content, accuracy was about equal for both instruments; for measurements of the area of the region of interest, accuracy was better with the DEXA instrument. With both instruments, fat had little effect on bone mineral density in bone phantom studies. Measurements on both instruments were influenced by the location of a bone phantom within the photon beam. Results in patients showed good correlation (r = 0.988) for bone mineral density. Measurements of bone mineral density in patients were consistently lower with the DEXA instrument because of better accuracy in area measurements. The new x-ray-based instrument is a major advance in bone mineral absorptiometry and provides improved, yet less expensive, measurements in research and clinical applications.

  4. Imaging-Based Methods for Non-invasive Assessment of Bone Properties Influenced by Mechanical Loading

    PubMed Central

    Lorbergs, Amanda L.

    2012-01-01

    ABSTRACT Purpose: To describe the most common in vivo imaging-based research tools used to assess bone properties that are influenced by mechanical loading associated with exercise, habitual physical activity, or disease states. Bone is a complex metabolically active tissue that adapts to changes in mechanical loading by altering the amount and spatial organization of mineral. Method: Using a narrative review design, the authors provide an overview of bone biology and biomechanics to emphasize the importance of bone size scale, porosity, and degree of mineralization when interpreting measures acquired using quantitative ultrasound (QUS), dual-energy X-ray absorptiometry (DXA), computed tomography (CT), magnetic resonance imaging (MRI), and finite element analysis (FEA). For each imaging modality, basic imaging principles, typical outcome measures associated with changes in mechanical loading, and salient features for physiotherapists are described. Main Results: While each imaging modality has strengths and limitations, currently CT-based methods are best suited for determining the effects of mechanical loading on bone properties—particularly in the peripheral skeleton. Conclusions: Regardless of the imaging technology used, the physiotherapist must carefully consider the assumptions of the imaging-based method, the clinical context, the nature of the change in mechanical loading, and the expected time course for change in bone properties. PMID:23449969

  5. Simplified method of clinical phenotyping for older men and women using established field-based measures.

    PubMed

    Fukuda, David H; Smith-Ryan, Abbie E; Kendall, Kristina L; Moon, Jordan R; Stout, Jeffrey R

    2013-12-01

    The purpose of this investigation was to determine body composition classification using field-based testing measurements in healthy elderly men and women. The use of isoperformance curves is presented as a method for this determination. Baseline values from 107 healthy Caucasian men and women, over the age of 65years old, who participated in a separate longitudinal study, were used for this investigation. Field-based measurements of age, height, weight, body mass index (BMI), and handgrip strength were recorded on an individual basis. Relative skeletal muscle index (RSMI) and body fat percentage (FAT%) were determined by dual-energy X-ray absorptiometry (DXA) for each participant. Sarcopenia cut-off values for RSMI of 7.26kg·m(-2) for men and 5.45kg·m(-2) for women and elderly obesity cut-off values for FAT% of 27% for men and 38% for women were used. Individuals above the RSMI cut-off and below the FAT% cut-off were classified in the normal phenotype category, while individuals below the RSMI cut-off and above the FAT% cut-off were classified in the sarcopenic-obese phenotype category. Prediction equations for RSMI and FAT% from sex, BMI, and handgrip strength values were developed using multiple regression analysis. The prediction equations were validated using double cross-validation. The final regression equation developed to predict FAT% from sex, BMI, and handgrip strength resulted in a strong relationship (adjusted R(2)=0.741) to DXA values with a low standard error of the estimate (SEE=3.994%). The final regression equation developed to predict RSMI from the field-based testing measures also resulted in a strong relationship (adjusted R(2)=0.841) to DXA values with a low standard error of the estimate (SEE=0.544kg·m(-2)). Isoperformance curves were developed from the relationship between BMI and handgrip strength for men and women with the aforementioned clinical phenotype classification criteria. These visual representations were used to aid in the

  6. Validation of a New Skinfold Prediction Equation Based on Dual-Energy X-Ray Absorptiometry

    ERIC Educational Resources Information Center

    Ball, Stephen; Cowan, Celsi; Thyfault, John; LaFontaine, Tom

    2014-01-01

    Skinfold prediction equations recommended by the American College of Sports Medicine underestimate body fat percentage. The purpose of this research was to validate an alternative equation for men created from dual energy x-ray absorptiometry. Two hundred ninety-seven males, aged 18-65, completed a skinfold assessment and dual energy x-ray…

  7. Urinary Deoxypyridinoline Level Reveals Bone Resorption, Predicts Fracture Risk, And Enhances the Results of Dual Energy X-ray Absorptiometry.

    PubMed

    Kells, John; Dollbaum, Charles M

    2009-01-01

    Bone loss leads to an increased incidence of fracture and is associated with the development of osteoporosis, which can strike people of any age and afflicts 10 million individuals in the U.S. today. Research indicates that osteoporosis causes more than 1.5 million fractures annually, including approximately 300,000 fractures at other sites. Early detection of bone loss (resorption), like that revealed by a combination of dual energy X-ray absorptiometry and monitoring the level of deoxypyridinoline in urine, provides the most complete picture of long-term and short-term bone health. In this reports, we examine the effects of increased bone resorption and various methods of testing for bone loss, present findings from the literature on the effects of and monitorying for bone resorption, and profile individuals most likely to benefit from testing for a decrease in bone mass. PMID:23965324

  8. Comparison of the Lunar Prodigy and iDXA Dual-Energy X-ray Absorptiometers for Assessing Total and Regional Body Composition.

    PubMed

    Morrison, Shannon A; Petri, Robert M; Hunter, Heather L; Raju, Dheeraj; Gower, Barbara

    2016-01-01

    The objective of the study was to assess the agreement of the Lunar Prodigy with the newer Lunar iDXA dual-energy X-ray absorptiometer for determining total body and regional (arms, legs, trunk) bone mineral density (BMD), bone mineral content (BMC), fat mass (FM), lean tissue mass (LTM), total body mass, and percent fat. Ninety-two healthy adult males (n = 36) and females (n = 56) were scanned consecutively on the iDXA and the Prodigy dual-energy X-ray absorptiometers. For iDXA, relative to Prodigy, paired t tests indicated significantly lower estimates for total body and regional BMD and BMC (p < 0.001). Measures of total body and trunk FM, LTM, and percent fat did not differ between the instruments. In regional analyses, estimates of FM and percent fat were greater, and that of LTM was lower, in the arms (p < 0.001). In contrast, iDXA estimates of LTM were higher in the legs (p < 0.001). All body composition measures were significantly correlated (p < 0.001). Bland-Altman analyses indicated that significant bias existed between iDXA and Prodigy for total body and regional BMD estimates (p < 0.001) such that iDXA underestimated BMD to a greater extent in persons with higher values. In addition, iDXA overestimation bias existed for FM in total body, arms, and legs, and the overestimation was primarily observed in participants with greater body fat (p < 0.001). When combining or comparing data from iDXA with those from Prodigy, investigators should be aware that certain total body and regional estimates are significantly different. The greatest percent differences were observed for arm BMD, FM, and percent fat. PMID:26209017

  9. Measurement of spine and total body mineral by dual-photon absorptiometry

    NASA Technical Reports Server (NTRS)

    Mazess, R. B.; Young, D.

    1983-01-01

    The use of Gd-153 dual-photon absorptiometry at 43 and 100 keV to measure individual-bone and total-body bone minerals is discussed in a survey of recent studies on humans, phantoms, and monkeys. Precision errors of as low as 1 percent have been achieved in vivo, suggesting the use of sequential measurements in studies of immobilization and space-flight effects.

  10. Precision error in dual-photon absorptiometry related to source age

    SciTech Connect

    Ross, P.D.; Wasnich, R.D.; Vogel, J.M.

    1988-02-01

    An average, variable precision error of up to 6% related to source age was observed for dual-photon absorptiometry of the spine in a longitudinal study of bone mineral content involving 393 women. Application of a software correction for source decay compensated for only a portion of this error. The authors conclude that measurement of bone-loss rates using serial dual-photon bone mineral measurements must be interpreted with caution.

  11. Application of the scaling index method to μCT images of human trabecular bone for the characterization of biomechanical strength

    NASA Astrophysics Data System (ADS)

    Monetti, Roberto A.; Bauer, Jan; Müller, Dirk; Rummeny, Ernst; Matsuura, Maiko; Eckstein, Felix; Link, Thomas; Räth, Christoph

    2007-03-01

    Osteoporosis is a metabolic bone disorder characterized by the loss of bone mineral density (BMD) and the deterioration of the bone micro-architecture. Rarefied bone structures are more susceptible to fractures which are the worst complications of osteoporosis. Here, we apply a structure characterization method, namely the Scaling Index Method, to micro-computed tomographic (μ-CT) images of the distal radius and extract 3D nonlinear structure measures to assess the biomechanical properties of trabecular bone. Biomechanical properties were quantified by the maximum compressive strength (MCS) obtained in a biomechanical test and bone mineral density (BMD) was calculated using dual X-ray absorptiometry (DXA). μ-CT images allow for the application of two different modalities of the SIM which differ in the dimensional embedding of the image. Both representations lead to similar correlation coefficients with MCS which are significantly better than the ones obtained using standard 3D morphometric parameters and comparable to the result given by BMD. The analysis of μ-CT images based on the SIM allows for a sharp distinction of the different structural elements which compose the trabecular bone network.

  12. Single- and dual-photon absorptiometry in osteoporosis and osteomalacia

    SciTech Connect

    Wahner, H.W.

    1987-10-01

    Single- and dual-photon absorptiometric methods have been used in the past to identify populations at risk for bone loss, to define the osteoporotic syndrome in terms of bone mass, and to evaluate treatment regimens to prevent bone loss. Technical improvements have made these procedures available for the nontraumatic measurement of bone mineral in the management of the individual patient suspected of having osteoporosis or other bone loss. This requires a different approach to data interpretation because decisions have to be made on the basis of a single measurement. Osteoporosis and osteomalacia cannot be distinguished by bone mineral measurements because both are characterized by a decrease in content of bone mineral. Bone mineral measurements can be used to assess the risk of fracture and, with it, the severity of bone loss. This allows treatment decisions to be made. Repeated measurements made under well-defined conditions allow estimation of long-term rate of bone loss and monitoring of treatment effect. 38 references.

  13. Quantitative computed tomographic evaluation of femoral bone mineral content in renal osteodystrophy compared with radial photon absorptiometry

    SciTech Connect

    Sakurai, K.; Marumo, F.; Iwanami, S.; Uchida, H.; Matsubayashi, T.

    1989-05-01

    The computed tomography (CT) numbers of cortical bone at the level of 20 cm (CT20) and of spongiosa in the lateral condyle at the level of 2 cm (CT02) from the distal end of the femur were obtained by a quantitative CT method and compared with the bone mineral density of mostly cortical bone within the radius (BMD) by photon absorptiometry. The study included 47 patients with chronic renal failure not dialyzed or induced to regular hemodialysis within 4 weeks of the study (group 1), 28 patients on regular hemodialysis for more than one month (group 2), and ten healthy volunteers (group 3). The measures of bone mineral content (BMC), namely CT20, CT02, and BMD, were compared in terms of their abilities to distinguish members in the various groups. For group 1 and group 3, the greatest variation in BMC was in the difference in CT02, which was primarily a measurement of the BMC of spongiosa. For groups 1 and 2, the greatest variation was in the difference in BMD, which was primarily a measurement of the BMC of cortex. The reproducibility of CT02 was estimated as almost equal to the difference in CT02 values at intervals of 10 months' duration of hemodialysis. The results indicated that CT02 was a useful measurement for evaluating the progress in the early stage of the renal osteodystrophy, and it is recommended that the bone mineral measurement with this QCT method should be performed once or twice a year.

  14. X-ray absorptiometry of the breast using mammographic exposure factors: application to units featuring automatic beam quality selection.

    PubMed

    Kotre, C J

    2010-06-01

    A number of studies have identified the relationship between the visual appearance of high breast density at mammography and an increased risk of breast cancer. Approaches to quantify the amount of glandular tissue within the breast from mammography have so far concentrated on image-based methods. Here, it is proposed that the X-ray parameters automatically selected by the mammography unit can be used to estimate the thickness of glandular tissue overlying the automatic exposure sensor area, provided that the unit can be appropriately calibrated. This is a non-trivial task for modern mammography units that feature automatic beam quality selection, as the number of tube potential and X-ray target/filter combinations used to cover the range of breast sizes and compositions can be large, leading to a potentially unworkable number of curve fits and interpolations. Using appropriate models for the attenuation of the glandular breast in conjunction with a constrained set of physical phantom measurements, it is demonstrated that calibration for X-ray absorptiometry can be achieved despite the large number of possible exposure factor combinations employed by modern mammography units. The main source of error on the estimated glandular tissue thickness using this method is shown to be uncertainty in the measured compressed breast thickness. An additional correction for this source of error is investigated and applied. Initial surveys of glandular thickness for a cohort of women undergoing breast screening are presented. PMID:20505033

  15. Assessment of Body Composition Using Dual Energy X-Ray Absorptiometry in Patients with Liver Cirrhosis: Comparison with Anthropometry

    PubMed Central

    Jeong, Seong Han; Lee, Jeong A; Kim, Jin A; Lee, Mun Woo; Chae, Hee Bok; Choi, Won Jun; Shin, Hyoung Shik; Lee, Ki Hyeong; Youn, Sei Jin; Koong, Sung Soo; Park, Seon Mee

    1999-01-01

    Objectives The aim of this study was to evaluate changes of body composition in cirrhotic patients. Dual energy x-ray absorptiometry (DEXA) and anthropometry were used, and the values obtained were compared. Methods Mid-arm fat and muscle areas were calculated by anthropometry in 66 cirrhotic patients and 94 healthy controls. In 37 of the cirrhotic patients and 39 of the controls, fat mass, lean soft tissue mass and bone mineral contents were measured with DEXA. Results The number of cirrhotic patients with measured values below the fifth percentile of normal controls was 21 (31.8%) by mid-arm fat area, six (9.1%) by mid-arm muscle area, 15 (40.5%) by fat mass and 0 (0%) by lean soft tissue mass. The fat mass in cirrhotic patients was less than in controls, whereas lean soft tissue mass and bone mineral content were not different. Fat depletion was severe in Child-class C patients and with severe ascites. Mid-arm fat area and fat mass showed close correlation (r = 0.85, p<0.01), but mid-arm muscle area and lean soft tissue mass showed poor correlation (r = 0.32, p<0.05). Conclusion Cirrhotic patients showed lower fat component, with preserved lean soft tissue mass and bone mineral content. In clinical practice, the measurement of mid-arm fat area was useful for the assessment of fat mass. PMID:10461427

  16. Techniques for deriving tissue structure from multiple projection dual-energy x-ray absorptiometry

    NASA Technical Reports Server (NTRS)

    Charles, Jr., Harry K. (Inventor); Beck, Thomas J. (Inventor); Feldmesser, Howard S. (Inventor); Magee, Thomas C. (Inventor)

    2004-01-01

    Techniques for deriving bone properties from images generated by a dual-energy x-ray absorptiometry apparatus include receiving first image data having pixels indicating bone mineral density projected at a first angle of a plurality of projection angles. Second image data and third image data are also received. The second image data indicates bone mineral density projected at a different second angle. The third image data indicates bone mineral density projected at a third angle. The third angle is different from the first angle and the second angle. Principal moments of inertia for a bone in the subject are computed based on the first image data, the second image data and the third image data. The techniques allow high-precision, high-resolution dual-energy x-ray attenuation images to be used for computing principal moments of inertia and strength moduli of individual bones, plus risk of injury and changes in risk of injury to a patient.

  17. Assessing Body Composition of Children and Adolescents Using Dual-Energy X-Ray Absorptiometry, Skinfolds, and Electrical Impedance

    ERIC Educational Resources Information Center

    Mooney, Angela; Kelsey, Laurel; Fellingham, Gilbert W.; George, James D.; Hager, Ron L.; Myrer, J. William; Vehrs, Pat R.

    2011-01-01

    To determine the validity and reliability of percent body fat estimates in 177 boys and 154 girls between 12-17 years of age, percent body fat was assessed once using dual-energy X-ray absorptiometry and twice using the sum of two skinfolds and three bioelectrical impedance analysis devices. The assessments were repeated on 79 participants on a…

  18. Relationship between alveolar bone measured by /sup 125/I absorptiometry with analysis of standardized radiographs: 2. Bjorn technique

    SciTech Connect

    Ortman, L.F.; McHenry, K.; Hausmann, E.

    1982-05-01

    The Bjorn technique is widely used in periodontal studies as a standardized measure of alveolar bone. Recent studies have demonstrated the feasibility of using /sup 125/I absorptiometry to measure bone mass. The purpose of this study was to compare /sup 125/I absorptiometry with the Bjorn technique in detecting small sequential losses of alveolary bone. Four periodontal-like defects of incrementally increasing size were produced in alveolar bone in the posterior segment of the maxilla of a human skull. An attempt was made to sequentially reduce the amount of bone in 10% increments until no bone remained, a through and through defect. The bone remaining at each step was measured using /sup 125/I absorptiometry. At each site the /sup 125/I absorptiometry measurements were made at the same location by fixing the photon source to a prefabricated precision-made occlusal splint. This site was just beneath the crest and midway between the borders of two adjacent teeth. Bone loss was also determined by the Bjorn technique. Standardized intraoral films were taken using a custom-fitted acrylic clutch, and bone measurements were made from the root apex to coronal height of the lamina dura. A comparison of the data indicates that: (1) in early bone loss, less than 30%, the Bjorn technique underestimates the amount of loss, and (2) in advanced bone loss, more than 60% the Bjorn technique overestimates it.

  19. Body Composition Comparison: Bioelectric Impedance Analysis with Dual-Energy X-Ray Absorptiometry in Adult Athletes

    ERIC Educational Resources Information Center

    Company, Joe; Ball, Stephen

    2010-01-01

    The primary purpose of this study was to investigate the accuracy of the DF50 (ImpediMed Ltd, Eight Mile Plains, Queensland, Australia) bioelectrical impedance analysis device using dual-energy x-ray absorptiometry as the criterion in two groups: endurance athletes and power athletes. The secondary purpose was to develop accurate body fat…

  20. MRI-measured pelvic bone marrow adipose tissue is inversely related to DXA-measured bone mineral in younger and older Adults

    PubMed Central

    Shen, Wei; Chen, Jun; Gantz, Madeleine; Punyanitya, Mark; Heymsfield, Steven B; Gallagher, Dympna; Albu, Jeanine; Engelson, Ellen; Kotler, Donald; Pi-Sunyer, Xavier; Gilsanz, Vicente

    2012-01-01

    Background/Objective Recent research has shown an inverse relationship between bone marrow adipose tissue (BMAT) and bone mineral density (BMD). There is a lack of evidence at the macro-imaging level to establish whether increased BMAT is a cause or effect of bone loss. This cross-sectional study compared the BMAT and BMD relationship between a younger adult group at or approaching peak bone mass (PBM) (age 18.0-39.9 yrs) and an older group with potential bone loss (PoBL) (age 40.0-88 yrs). Subjects/Methods Pelvic BMAT was evaluated in 560 healthy men and women with T1-weighted whole body magnetic resonance imaging. BMD was measured using whole body dual-energy x-ray absorptiometry. Results An inverse correlation was observed between pelvic BMAT and pelvic, total, and spine BMD in the younger PBM group (r=-0.419 to -0.461, P<0.001) and in the older PoBL group (r=-0.405 to -0.500, P<0.001). After adjusting for age, sex, ethnicity, menopausal status, total body fat, skeletal muscle, subcutaneous and visceral adipose tissue, neither subject group (younger PBM vs. older PoBL) nor its interaction with pelvic BMAT significantly contributed to the regression models with BMD as dependent variable and pelvic BMAT as independent variable (P=0.434 to 0.928). Conclusion Our findings indicate that an inverse relationship between pelvic BMAT and BMD is present both in younger subjects who have not yet experienced bone loss and also in older subjects. These results provide support at the macro-imaging level for the hypothesis that low BMD may be a result of preferential differentiation of mesenchymal stem cells from osteoblasts to adipocytes. PMID:22491495

  1. RACE AND ETHNIC EFFECT OF ESTIMATING DXA PERCENT FAT FROM BMI: THE TIGER STUDY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    PURPOSE Body mass index (BMI) has become the accepted public health standard of determining overweight (BMI = 25 kg/m2) and obese (BMI = 30 kg/m2). This study examined the effect of race and sex on estimating percent fat (%fat) using BMI. METHODS The subjects were 85 women and 39 men who ranged in ...

  2. Dual photon absorptiometry using a gadolinium-153 source applied to measure equine bone mineral content

    NASA Astrophysics Data System (ADS)

    Moure, Alessandro; Reichmann, Peter; Remigio Gamba, Humberto

    2003-12-01

    The application of the dual photon absorptiometry (DPA) technique, using gadolinium-153 as the photon source, to evaluate the bone mineral density (BMD) of the third metacarpal bone of horses is presented. The radiation detector was implemented with a NaI(TI) scintillator coupled to a 14 stage photomultiplier. A modular mechanical system allows the position of the prototype to be adjusted in relation to the animal. A moveable carrier makes it possible to scan the third metacarpal with a velocity adjustable between 1 and 12 mm s-1, in steps of 1 mm s-1, for a total distance of 250 mm. The prototype was evaluated with a phantom of the third metacarpal bone made of perspex and aluminium, and in vitro with a transverse slice of the third metacarpal bone of a horse. The tests showed that the prototype has an accuracy and precision of, approximately, 10% and 6%, respectively, for a 6 s acquisition time. Preliminary studies carried out in three foals from birth to one year of age indicated that the prototype is well suited to in vivo and in situ analysis of the BMD of the third metacarpal bones of horses, making it possible to evaluate the changes of BMD levels on a monthly basis. Also, results indicated an exponential behaviour of the BMD curve during the first year of life of the studied horses.

  3. Body fat from body density: underwater weighing vs. dual-photon absorptiometry.

    PubMed

    Wang, J; Heymsfield, S B; Aulet, M; Thornton, J C; Pierson, R N

    1989-06-01

    We measured fat in 286 healthy volunteers by underwater weighing (FUWW) and dual-photon absorptiometry (FDPA) to develop a translation table for the differing results from these entirely different techniques and to study the sources of these differences. In 99 males and 187 females aged 19-94 yr, fatness was 7-47%. Prediction equations are presented for FUWW-FDPA (delta F), density of lean body mass (DLBM), and FDPA. FUWW and FDPA were significantly different from each other (P less than 0.01). Calculated DLBM is less than the assumed constant of 1.10 (P less than 0.01), ranging widely from 1.05 to 1.13 and being highly correlated with the ratio of total body bone mineral to lean body mass (TBBM/LBM). delta F, the differences between FUWW and FDPA measurements in individual subjects, varied widely (-7 to +11% in males and -18 to +13% in females). The difference was positively correlated with the DLBM. FUWW was no better than anthropometrics in equations for predicting FDPA. The FDPA predicted from anthropometrics showed smaller standard errors than when FUWW was used. Neither anthropometrics nor FUWW equations are clearly superior to those previously available. PMID:2735405

  4. Accuracy of lumbar spine bone mineral content by dual photon absorptiometry

    SciTech Connect

    Gotfredsen, A.; Podenphant, J.; Norgaard, H.; Nilas, L.; Nielsen, V.A.; Christiansen, C.

    1988-02-01

    The accuracy of measurement of the bone mineral content (BMC, g) and bone mineral density (BMD, g/cm/sup 2/) of the lumbar spine by dual photon absorptiometry (DPA) was estimated by means of two different spine scanners (a Nuclear Data 2100 and a Lunar Radiation DP3). The lumbar spines of 13 cadavers were used. BMC and BMD were measured in situ and on the excised vertebrae in a solution of water/ethanol; and covered with ox muscle/porcine muscle/lard. The actual mineral weight and areal density were determined after chemical maceration, fat extraction, drying to a constant weight, ashing for 24 hr at 600 degrees C, and correction for the transverse processes. The true are was measured by parallax free X rays and planimetry. All measurements of BMC or BMD were highly interrelated (r = 0.94-0.99). The standard error of estimate (s.e.e.) of BMC in situ versus BMC in water/ethanol was 5.2%. The agreement between the BMD values of the two scanners was very good (s.e.e. = 2.9%). BMC in situ predicted the actual vertebral mineral mass with an s.e.e. of 8.1%. BMD in situ and BMD in water/ethanol predicted the actual area density with s.e.e.s of 10.3% and 5.0%, respectively. This study discloses the correlation and accuracy error of spinal DPA measurements in situ in whole cadavers versus the actual BMC and BMD. The error, which is underestimated in in vitro studies, amounts to 10%.

  5. Accuracy of dual-photon absorptiometry compared to computed tomography of the spine

    SciTech Connect

    Mazess, R.; Vetter, J.; Towsley, M.; Perman, W.; Holden, J.

    1984-01-01

    Dual-photon absorptiometry (DPA) was done using Gd-153 (44 and 100keV) in vivo and on various bone specimens including 39 vertebrae and 24 femora. The precision error for triplicate determinations on individual vertebrae was 3.3%, 2.9%, and 1.7% for bone mineral content (BMC), projected area, and areal density of bone mineral (BMD) respectively. The accuracy of determinations was 3-4% on the femora and 5% on the vertebrae. Computed tomography (CT) determinations were done on seven vertebrae immersed in alcohol (50%) to simulate the effects of marrow fat. CT measurements were done using a dual-energy scanner (Siemens) from which single-energy data files also were analyzed. There was a high correlation between Gd-153 DPA scans and either single- or dual-energy CT scans of the same vertebrae (rapprox. =0.97). For dual-energy CT the determined bone values were only 2% higher than the Gd-153 DPA values; however, single-energy CT scans showed a marked deviation. The CT values at 75kVp were 38% lower than those obtained from dual-energy CT scans or from Gd-153 DPA scans, while the values at 125kVp were 46% lower. Calcium chloride solutions made up with 50% alcohol showed the same systematic error of single-energy CT. Dual-energy determinations are mandatory on trabecular bone in order to avoid the errors introduced by variable marrow fat. The magnitude of the latter error depends upon the energy of the CT scan.

  6. Study of sex differences in the association between hip fracture risk and body parameters by DXA-based biomechanical modeling.

    PubMed

    Nasiri, Masoud; Luo, Yunhua

    2016-09-01

    There is controversy about whether or not body parameters affect hip fracture in men and women in the same way. In addition, although bone mineral density (BMD) is currently the most important single discriminator of hip fracture, it is unclear if BMD alone is equally effective for men and women. The objective of this study was to quantify and compare the associations of hip fracture risk with BMD and body parameters in men and women using our recently developed two-level biomechanical model that combines a whole-body dynamics model with a proximal-femur finite element model. Sideways fall induced impact force of 130 Chinese clinical cases, including 50 males and 80 females, were determined by subject-specific dynamics modeling. Then, a DXA-based finite element model was used to simulate the femur bone under the fall-induced loading conditions and calculate the hip fracture risk. Body weight, body height, body mass index, trochanteric soft tissue thickness, and hip bone mineral density were determined for each subject and their associations with impact force and hip fracture risk were quantified. Results showed that the association between impact force and hip fracture risk was not strong enough in both men (r=-0.31,p<0.05) and women (r=0.42,p<0.001) to consider the force as a sole indicator of hip fracture risk. The correlation between hip BMD and hip fracture risk in men (r=-0.83,p<0.001) was notably stronger than that in women (r=-0.68,p<0.001). Increased body mass index was not a protective factor against hip fracture in men (r=-0.13,p>0.05), but it can be considered as a protective factor among women (r=-0.28,p<0.05). In contrast to men, trochanteric soft tissue thickness can be considered as a protective factor against hip fracture in women (r=-0.50,p<0.001). This study suggested that the biomechanical risk/protective factors for hip fracture are sex-specific. Therefore, the effect of body parameters should be considered differently for men and women in hip

  7. Validation of dual-energy X-ray absorptiometry in live White Leghorns.

    PubMed

    Schreiweis, M A; Orban, J I; Ledur, M C; Moody, D E; Hester, P Y

    2005-01-01

    Dual energy x-ray absorptiometry (DEXA) was evaluated for use as a noninvasive tool to monitor skeletal integrity in live laying hens. The objectives of the current study were 1) to validate the use of DEXA in evaluating bone integrity in live birds as compared with excised bones under a normal nutritional regimen as well as in hens fed varying levels of dietary Ca and 2) to correlate densitometric scans with other bone strength criteria and egg traits. Densitometric scans were conducted on the tibia and humerus of live hens at 10-wk intervals from 17 to 67 wk of age. After each scan, bones were excised from euthanized hens to measure breaking strength characteristics and bone ash (experiment 1). Similar measurements were collected at 38, 48, and 58 wk of age from hens fed hypercalcemic (5.4%), control (3.6%), and hypocalcemic (1.8%) diets from 32 to 58 wk of age (experiment 2). The bone mineral density (BMD) and bone mineral content (BMC) between live and excised bone scans were highly correlated (r = 0.85 and 0.92, respectively, P < 0.0001, experiment 1). Densitometric scans of live birds were positively correlated with bone breaking force and bone ash (r = 0.68 and 0.73, respectively, P < 0.001) with little to no correlation with shell traits. In experiment 2, the excised tibial scan had lower BMD and BMC than the live bird (P < 0.01), whereas no difference was detected in densitometric scans of the humerus. The live and excised BMD and BMC of the tibia (r = 0.87 and 0.82, respectively, P < 0.001) and humerus (r = 0.94 and 0.93, respectively, P < 0.001) were highly correlated. Due to the high correlations between live and excised bone scans and the significant correlations of live scans to more traditional invasive bone measurement tests such as bone breaking force and bone ash, we concluded that DEXA is a useful noninvasive tool for evaluating skeletal integrity in live birds. PMID:15685947

  8. Errors in longitudinal measurements of bone mineral: effect of source strength in single and dual photon absorptiometry

    SciTech Connect

    Dunn, W.L.; Kan, S.H.; Wahner, H.W.

    1987-11-01

    The effect of changing strength during the useful life of a radiation source was evaluated in studies performed on four dual photon (DPA) and two single photon (SPA) bone absorptiometry instruments. Two DPA units and one SPA unit did not show any systematic dependence of measured bone mineral content or bone mineral areal density (BMD) on source activity when evaluated over an entire source life. One DPA and one SPA instrument, however, showed significant time trends associated with source activity. The fourth DPA instrument had a significant linear decrease in BMD over a source life in the automatic mode but performed better in the manual mode.

  9. Comparison of Body Composition Assessed by Dual-Energy X-Ray Absorptiometry and BMI in Current and Former U.S. Navy Service Members

    PubMed Central

    Gasier, Heath G.; Hughes, Linda M.; Young, Colin R.; Richardson, Annely M.

    2015-01-01

    Background Little is known of the diagnostic accuracy of BMI in classifying obesity in active duty military personnel and those that previously served. Thus, the primary objectives were to determine the relationship between lean and fat mass, and body fat percentage (BF%) with BMI, and assess the agreement between BMI and BF% in defining obesity. Methods Body composition was measured by dual-energy X-ray absorptiometry in 462 males (20–91 years old) who currently or previously served in the U.S. Navy. A BMI of ≥ 30 kg/m2 and a BF% ≥ 25% were used for obesity classification. Results The mean BMI (± SD) and BF% were 28.8 ± 4.1 and 28.9 ± 6.6%, respectively, with BF% increasing with age. Lean mass, fat mass, and BF% were significantly correlated with BMI for all age groups. The exact agreement of obesity defined by BMI and BF% was fair (61%), however, 38% were misclassified by a BMI cut-off of 30 when obesity was defined by BF%. Conclusions From this data we determined that there is a good correlation between body composition and BMI, and fair agreement between BMI and BF% in classifying obesity in a group of current and former U.S. Navy service members. However, as observed in the general population, a significant proportion of individuals with excess fat are misclassified by BMI cutoffs. PMID:26197480

  10. Validity of segmental multiple-frequency bioelectrical impedance analysis to estimate body composition of adults across a range of body mass indexes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Objective: Compare estimates of body composition using segmental, multiple frequency bioelectrical impedance analysis (MF-BIA) with dual x-ray absorptiometry (DXA) in healthy adults across a range of body mass index (BMI). Methods: Percent body fat (%BF), fat-mass (FM), and fat-free mass (FFM) asses...

  11. Risk Factors for Osteoporosis Among Middle-Aged Women

    ERIC Educational Resources Information Center

    Turner, Lori W.; Wallace, Lorraine Silver; Perry, Blake Allen; Bleeker, Jeanne

    2004-01-01

    Objective: To investigate the risk factors for osteoporosis among a sample of middle-aged women. Methods: Adipose tissue and bone mineral density levels at the left femur, lumbar spine, and total body were assessed using dual-energy x-ray absorptiometry (DXA). Subjects (n=342) were surveyed regarding a variety of osteoporosis-related risk factors.…

  12. Maintenance of proximal bone mass with an uncemented femoral stem analysis with dual-energy x-ray absorptiometry.

    PubMed

    Wixson, R L; Stulberg, S D; Van Flandern, G J; Puri, L

    1997-06-01

    Bone ingrowth into uncemented femoral implants with proximal porous coatings has been designed to avoid proximal stress shielding and preserve femoral strength. Dual-energy x-ray absorptiometry allows repeated quantitative analysis of anteroposterior scans of the proximal femur. By use of dual-energy x-ray absorptiometry and qualitative radiographic changes, 31 total hip arthroplasties with an individually designed, proximally porous-coated prosthesis were evaluated after surgery and at intervals up to 2 years. All implants appeared to achieve successful bone ingrowth and subsequent remodeling. At the most proximal level around the neck osteotomy, the postoperative loss of bone density at 6 months was -14.5%, which persisted at 24 months with -11.6%. At the level of the distal portion of the porous coating in the lower metaphysis, the density change was -8.7%, but bone had remodeled at 24 months with a change in density of only -1.0% compared with the immediate postoperative scan. With a design that results in reliable proximal ingrowth, this study predicts that after an initial decline in bone density, a positive bone remodeling response occurs that could lead to long-term stable fixation of the femoral implant. PMID:9195311

  13. Experimental assessment of bone mineral density using quantitative computed tomography in holstein dairy cows.

    PubMed

    Maetani, Ayami; Itoh, Megumi; Nishihara, Kahori; Aoki, Takahiro; Ohtani, Masayuki; Shibano, Kenichi; Kayano, Mitsunori; Yamada, Kazutaka

    2016-08-01

    The aim of this study was to assess the measurement of bone mineral density (BMD) by quantitative computed tomography (QCT), comparing the relationships of BMD between QCT and dual-energy X-ray absorptiometry (DXA) and between QCT and radiographic absorptiometry (RA) in the metacarpal bone of Holstein dairy cows (n=27). A significant positive correlation was found between QCT and DXA measurements (r=0.70, P<0.01), and a significant correlation was found between QCT and RA measurements (r=0.50, P<0.01). We conclude that QCT provides quantitative evaluation of BMD in dairy cows, because BMD measured by QCT showed positive correlations with BMD measured by the two conventional methods: DXA and RA. PMID:27075115

  14. Experimental assessment of bone mineral density using quantitative computed tomography in holstein dairy cows

    PubMed Central

    MAETANI, Ayami; ITOH, Megumi; NISHIHARA, Kahori; AOKI, Takahiro; OHTANI, Masayuki; SHIBANO, Kenichi; KAYANO, Mitsunori; YAMADA, Kazutaka

    2016-01-01

    The aim of this study was to assess the measurement of bone mineral density (BMD) by quantitative computed tomography (QCT), comparing the relationships of BMD between QCT and dual-energy X-ray absorptiometry (DXA) and between QCT and radiographic absorptiometry (RA) in the metacarpal bone of Holstein dairy cows (n=27). A significant positive correlation was found between QCT and DXA measurements (r=0.70, P<0.01), and a significant correlation was found between QCT and RA measurements (r=0.50, P<0.01). We conclude that QCT provides quantitative evaluation of BMD in dairy cows, because BMD measured by QCT showed positive correlations with BMD measured by the two conventional methods: DXA and RA. PMID:27075115

  15. Dual-energy X-ray absorptiometry–based body volume measurement for 4-compartment body composition123

    PubMed Central

    Wilson, Joseph P; Mulligan, Kathleen; Fan, Bo; Sherman, Jennifer L; Murphy, Elizabeth J; Tai, Viva W; Powers, Cassidy L; Marquez, Lorena; Ruiz-Barros, Viviana

    2012-01-01

    Background: Total body volume (TBV), with the exclusion of internal air voids, is necessary to quantify body composition in Lohman's 4-compartment (4C) model. Objective: This investigation sought to derive a novel, TBV measure with the use of only dual-energy X-ray absorptiometry (DXA) attenuation values for use in Lohman's 4C body composition model. Design: Pixel-specific masses and volumes were calculated from low- and high-energy attenuation values with the use of first principle conversions of mass attenuation coefficients. Pixel masses and volumes were summed to derive body mass and total body volume. As proof of concept, 11 participants were recruited to have 4C measures taken: DXA, air-displacement plethysmography (ADP), and total body water (TBW). TBV measures with the use of only DXA (DXA-volume) and ADP-volume measures were compared for each participant. To see how body composition estimates were affected by these 2 methods, we used Lohman's 4C model to quantify percentage fat measures for each participant and compared them with conventional DXA measures. Results: DXA-volume and ADP-volume measures were highly correlated (R2 = 0.99) and showed no statistically significant bias. Percentage fat by DXA volume was highly correlated with ADP-volume percentage fat measures and DXA software-reported percentage fat measures (R2 = 0.96 and R2 = 0.98, respectively) but were slightly biased. Conclusions: A novel method to calculate TBV with the use of a clinical DXA system was developed, compared against ADP as proof of principle, and used in Lohman's 4C body composition model. The DXA-volume approach eliminates many of the inherent inaccuracies associated with displacement measures for volume and, if validated in larger groups of participants, would simplify the acquisition of 4C body composition to a single DXA scan and TBW measure. PMID:22134952

  16. Ethnic Variation in Body Composition Assessment in a Sample of Adolescent Girls

    PubMed Central

    Meyer, Katie A.; Friend, Sarah; Hannan, Peter J.; Himes, John H.; Demerath, Ellen W.; Neumark-Sztainer, Dianne

    2011-01-01

    Objective To examine whether bioelectrical impedance analysis (BIA) is a valid measure of body composition in a multiethnic sample of adolescent girls, as compared to dual-energy X-ray absorptiometry (DXA). Method Data were from a physical activity intervention study among 276 14–20 year-old sedentary American girls, including 74 whites, 85 blacks, 46 Hispanics, and 71 Asians. Height and weight were objectively measured. Body composition was assessed using a foot-to-foot BIA and a fan-beam DXA. Linear regression models quantified baseline cross-sectional estimates of percent body fat, fat mass, fat-free mass, fat mass index, and fat-free mass index and their BIA-DXA differences, which we considered an estimate of bias. Variation in BIA-DXA by ethnicity and DXA-assessed adiposity was examined with tests of statistical interaction. Results Compared to DXA measurement, BIA significantly underestimated percent body fat, fat mass, and fat mass index, and overestimated fat-free mass and fat-free mass index in each ethnic group. There was significant ethnic variation in BIA-DXA bias: percent body fat was underestimated by between 4.8% in blacks and 8.6% in Asians (p-value, interaction<0.001), as were fat mass (p-value=0.012) and fat mass index (p-value<0.001); fat-free mass index was overestimated (p-value=0.002). The degree of ethnic-specific bias varied according to DXA-assessed body composition values. For example, there was relatively greater ethnic variation in bias estimating percent body fat at lower DXA-assessed percent body fat values. Conclusion Compared to DXA, BIA underestimated measures of adiposity in a multiethnic adolescent sample. Further, BIA-DXA bias varied by ethnicity and across measures of adiposity. PMID:21749194

  17. Position statement: introduction, methods, and participants. The Writing Group for the International Society for Clinical Densitometry (ISCD) Position Development Conference.

    PubMed

    2004-01-01

    Following publication of the proceedings from the first Position Development Conference (PDC) of the International Society for Clinical Densitometry (ISCD), members of the ISCD Scientific Advisory Committee (SAC) addressed additional topics of interest in the field of bone densitometry. These topics were addressed at a subsequent PDC, which was held in Cincinnati, Ohio, July 25-27, 2003. Five topics were chosen for discussion: (1) the diagnosis of osteoporosis in men, premenopausal women, and children; (2) technical standardization for dual-energy X-ray absorptiometry (DXA); (3) indications for bone densitometry; (4) reporting of bone density results; and (5) nomenclature and decimal places for bone densitometry. This report describes the methodology used for the development, presentation, and finalization of PDC positions. These positions are discussed in the following papers. PMID:14742883

  18. Quick benefits of interval training versus continuous training on bone: a dual-energy X-ray absorptiometry comparative study.

    PubMed

    Boudenot, Arnaud; Maurel, Delphine B; Pallu, Stéphane; Ingrand, Isabelle; Boisseau, Nathalie; Jaffré, Christelle; Portier, Hugues

    2015-12-01

    To delay age-related bone loss, physical activity is recommended during growth. However, it is unknown whether interval training is more efficient than continuous training to increase bone mass both quickly and to a greater extent. The aim of this study was to compare the effects of a 10-week interval training regime with a 14-week continuous training regime on bone mineral density (BMD). Forty-four male Wistar rats (8 weeks old) were separated into four groups: control for 10 weeks (C10), control for 14 weeks (C14), moderate interval training for 10 weeks (IT) and moderate continuous training for 14 weeks (CT). Rats were exercised 1 h/day, 5 day/week. Body composition and BMD of the whole body and femur respectively were assessed by dual-energy X-ray absorptiometry at baseline and after training to determine raw gain and weight-normalized BMD gain. Both trained groups had lower weight and fat mass gain when compared to controls. Both trained groups gained more BMD compared to controls when normalized to body weight. Using a 30% shorter training period, the IT group showed more than 20% higher whole body and femur BMD gains compared to the CT. Our data suggest that moderate IT was able to produce faster bone adaptations than moderate CT. PMID:26754273

  19. The role of dual energy x-ray absorptiometry in aiding the diagnosis of pediatric osteogenesis imperfecta.

    PubMed

    Moore, M S; Minch, C M; Kruse, R W; Harcke, H T; Jacobson, L; Taylor, A

    1998-12-01

    The role of dual energy x-ray absorptiometry (DEXA) in the evaluation of the pediatric patient with multiple fractures has not been well established. We retrospectively examined the medical records of 45 patients who had presented to our institution with multiple fractures of unknown cause, who were not known to have osteogenesis imperfecta, and who had obtained DEXA as part of their evaluation. Of these, 26 patients had sufficient clinical data for inclusion in this study. Patients underwent DEXA of the anteroposterior spine and whole body. A z score was calculated to normalize the DEXA values for age. The diagnosis of osteogenesis imperfecta was correlated with the outcome of each DEXA scan to assess the validity of DEXA as a diagnostic tool. The DEXA of the anteroposterior spine had the highest sensitivity at 91.7%, while DEXA of the whole body had the highest specificity at 100.0%. Decreased bone mineral density may be associated with osteogenesis imperfecta, and DEXA is helpful in detecting low bone mineral density that may be missed on plain radiographs of children with milder forms of osteogenesis imperfecta. PMID:9880097

  20. Correspondence between theoretical models and dual energy x-ray absorptiometry measurements of femoral cross-sectional growth during adolescence

    NASA Technical Reports Server (NTRS)

    van der Meulen, M. C.; Marcus, R.; Bachrach, L. K.; Carter, D. R.

    1997-01-01

    We have developed an analytical model of long bone cross-sectional ontogeny in which appositional growth of the diaphysis is primarily driven by mechanical stimuli associated with increasing body mass during growth and development. In this study, our goal was to compare theoretical predictions of femoral diaphyseal structure from this model with measurements of femoral bone mineral and geometry by dual energy x-ray absorptiometry. Measurements of mid-diaphyseal femoral geometry and structure were made previously in 101 Caucasian adolescents and young adults 9-26 years of age. The data on measured bone mineral content and calculated section modulus were compared with the results of our analytical model of cross-sectional development of the human femur over the same age range. Both bone mineral content and section modulus showed good correspondence with experimental measurements when the relationships with age and body mass were examined. Strong linear relationships were evident for both parameters when examined as a function of body mass.

  1. Reducing the need for central dual-energy X-ray absorptiometry in postmenopausal women: efficacy of a clinical algorithm including peripheral densitometry.

    PubMed

    Jiménez-Núñez, Francisco Gabriel; Manrique-Arija, Sara; Ureña-Garnica, Inmaculada; Romero-Barco, Carmen María; Panero-Lamothe, Blanca; Descalzo, Miguel Angel; Carmona, Loreto; Rodríguez-Pérez, Manuel; Fernández-Nebro, Antonio

    2013-07-01

    We evaluated the efficacy of a triage approach based on a combination of osteoporosis risk-assessment tools plus peripheral densitometry to identify low bone density accurately enough to be useful for clinical decision making in postmenopausal women. We conducted a cross-sectional diagnostic study in postmenopausal Caucasian women from primary and tertiary care. All women underwent dual-energy X-ray absorptiometric (DXA) measurement at the hip and lumbar spine and were categorized as osteoporotic or not. Additionally, patients had a nondominant heel densitometry performed with a PIXI densitometer. Four osteoporosis risk scores were tested: SCORE, ORAI, OST, and OSIRIS. All measurements were cross-blinded. We estimated the area under the curve (AUC) to predict the DXA results of 16 combinations of PIXI plus risk scores. A formula including the best combination was derived from a regression model and its predictability estimated. We included 505 women, in whom the prevalence of osteoporosis was 20 %, similar in both settings. The best algorithm was a combination of PIXI + OST + SCORE with an AUC of 0.826 (95 % CI 0.782-0.869). The proposed formula is Risk = (-12) × [PIXI + (-5)] × [OST + (-2)] × SCORE and showed little bias in the estimation (0.0016). If the formula had been implemented and the intermediate risk cutoff set at -5 to 20, the system would have saved 4,606.34 in the study year. The formula proposed, derived from previously validated risk scores plus a peripheral bone density measurement, can be used reliably in primary care to avoid unnecessary central DXA measurements in postmenopausal women. PMID:23608922

  2. Estimation of length or height in infants and young children using ulnar and lower leg length with dual-energy X-ray absorptiometry validation

    PubMed Central

    Weidauer, Lee; Wey, Howard; Slater, Hillarie; Moyer-Mileur, Laurie; Specker, Bonny

    2014-01-01

    AIM We compared the accuracy and reproducibility of using ulnar and lower leg length measurements to predict length and height in infants and children aged 0–6 years. METHOD Length/height and ulnar and lower leg length were measured in 352 healthy preterm and term -born children (16 males, 185 females). Ulna length was measured as the distance between the proximal olecranon process and the distal styloid process of the ulna. Tibia length was measured as the distance from the proximal aspect of the medial condyle and the most distal aspect of the medial malleolus of the tibia using a segmometer. Length measurements were taken using an infant length board in children less than 24 months of age, whereas a portable stadiometer was used to measure height in older children. Equations were developed using ulnar and lower leg length and age. Intra- and inter-examiner variability (n=167) was calculated, and dual-energy X-ray absorptiometry scans (n=126) were used to determine accuracy of limb lengths. Results Ulnar and lower leg length explained over 95% of the variability in length/height in term infants and children, but less in preterm infants (R2=0.80–0.87). In preterm infants, the limits of agreement (LOA) for males were −2.44 to 2.44cm and −2.88 to 2.88cm for the ulna and lower leg respectively, whereas the LOA for females were −1.90 to 1.90cm and −1.87 to 1.87cm respectively. In older children, the LOA for males were −5.53 to 4.48cm and −5.59 to 4.62cm for the ulna and lower leg respectively, whereas the LOA for females were −5.57 to 5.01cm and −6.02 to 5.02cm respectively. Intra- and inter-examiner variability was low for all measurements in both sexes and age groups. INTERPRETATION Length and height measurements using infant length board or stadiometer are reproducible. Because of the wide limits of agreement, estimation of length and height in children using ulnar and lower leg length is not an acceptable alternative to traditional methods

  3. Bone microarchitecture and bone fragility in men: DXA and histomorphometry in humans and in the orchidectomized rat model.

    PubMed

    Audran, M; Chappard, D; Legrand, E; Libouban, H; Baslé, M F

    2001-10-01

    In men, the risk of fragility fractures increases as bone mineral declines but there is an overlap in the bone mineral density (BMD) measurements between patients with and those without fractures. Biomechanical competence of trabecular (Tb) bone depends on the amount of bone and on microarchitecture. We have developed new histomorphometric methods for evaluating microarchitecture on histological sections. These methods were used in the orchidectomized male rat (ORX--a model of hypogonadism-induced osteoporosis) and on transiliac bone biopsies performed in male osteoporotic patients. ORX rats were studied at 2, 4, 8, and 16 weeks post-ORX. Bone mineral content (BMC) was reduced at 16 weeks. Trabecular bone volume (BV/TV) was significantly decreased from the 4th week. Differences in the sensitivity of the methods were found. Fractal dimension was modified as early as 2 weeks and appeared the most potent descriptor of Tb disorganization. The architectural changes in this model mimic those observed in hypogonadic men. We examined the relationships among BMD, micro-architecture, and vertebral fracture in 108 men with lumbar osteopenia (T-score <-2.5). At least one vertebral fracture was observed in 62 patients and none in 46 patients. After adjusting for age, body mass index (BMI), and BMD, there was no significant difference between the two groups in BV/TV, Tb.Th, and Star volume. In contrast, the mean values of ICI and Tb.Sp were significantly higher whereas Tb.N and nodes were lower in patients with vertebral fracture. Logistic regression analysis showed that ICI, strut analysis, and Tb.N were significant predictors of the presence of vertebral fracture: odds ratios for an alteration of I SD ranged from 1.7 for nodes to 3.2 for ICI. These results strongly suggest that bone Tb microarchitecture is a major and independent determinant of vertebral fracture in men with osteoporosis. PMID:11730253

  4. Recommended Methods for Monitoring Skeletal Health in Astronauts to Distinguish Specific Effects of Prolonged Spaceflight

    NASA Technical Reports Server (NTRS)

    Vasadi, Lukas J.; Spector, Elizabeth R.; Smith, Scott A.; Yardley, Gregory L.; Evans, Harlan J.; Sibonga, Jean D.

    2016-01-01

    NASA uses areal bone mineral density (aBMD) by dual-energy X-ray absorptiometry (DXA) to monitor skeletal health in astronauts after typical 180-day spaceflights. The osteoporosis field and NASA, however, recognize the insufficiency of DXA aBMD as a sole surrogate for fracture risk. This is an even greater concern for NASA as it attempts to expand fracture risk assessment in astronauts, given the complicated nature of spaceflight-induced bone changes and the fact that multiple 1-year missions are planned. In the past decade, emerging analyses for additional surrogates have been tested in clinical trials; the potential use of these technologies to monitor the biomechanical integrity of the astronaut skeleton will be presented. OVERVIEW: An advisory panel of osteoporosis policy-makers provided NASA with an evidence-based assessment of astronaut biomedical and research data. The panel concluded that spaceflight and terrestrial bone loss have significant differences and certain factors may predispose astronauts to premature fractures. Based on these concerns, a proposed surveillance program is presented which a) uses Quantitative Computed Tomography (QCT) scans of the hip to monitor the recovery of spaceflight-induced deficits in trabecular BMD by 2 years after return, b) develops Finite Element Models [FEM] of QCT data to evaluate spaceflight effect on calculated hip bone strength and c) generates Trabecular Bone Score [TBS] from serial DXA scans of the lumbar spine to evaluate the effect of age, spaceflight and countermeasures on this novel index of bone microarchitecture. SIGNIFICANCE: DXA aBMD is a widely-applied, evidence-based predictor for fractures but not applicable as a fracture surrogate for premenopausal females and males <50 years. Its inability to detect structural parameters is a limitation for assessing changes in bone integrity with and without countermeasures. Collective use of aBMD, TBS, QCT, and FEM analysis for astronaut surveillance could

  5. Comparison of dual-photon absorptiometry systems for total-body bone and soft tissue measurements: Dual-energy X-rays versus gadolinium 153

    SciTech Connect

    Russell-Aulet, M.; Wang, J.; Thornton, J.; Pierson, R.N. Jr. )

    1991-04-01

    A total of 81 subjects (41 males and 40 females) were scanned by dual-photon absorptiometry by 153Gd source (DPA; Lunar DP4) and by dual-energy x-ray absorptiometry (DEXA; Lunar-DPX) within a 24 h period. Total-body bone mineral density (TBMD), calcium content (Ca), and soft tissue mass (ST) were determined with a precision of about 1-1.5% using DPA and 0.5-1.0% using DEXA. Measurements of TBMD, Ca, ST, bone area (area), percentage fat, and regional bone mineral densities (BMD) were compared. Paired t-tests showed small but significant differences between all measurements. Correlations (r) for TBMD, Ca, area, ST, percentage fat, arm BMD, leg BMD, and trunk BMD were 0.99, 0.99, 0.97, 0.99, 0.97, 0.99, 0.99, and 0.98. There were small systematic differences for TBMD (less than 1%), calcium (3%), bone area (3%), soft tissue mass (7%), and percentage fat (9%) between the two approaches. Regression equations are given relating these measurements.

  6. Methods for nurses to measure body composition.

    PubMed

    Moran, Jose Maria; Lavado-Garcia, Jesus Maria; Pedrera-Zamorano, Juan Diego

    2011-01-01

    Among the methods available for assessing body composition, traditional methods like hydrodensitometry and skin-fold measurements are well known. In this review, we focus on the impedance and interactance methods, which use systems that are usually inexpensive, easily transportable and simple to operate. We also discuss the usefulness of dual energy X-ray absorptiometry, particularly for the measurement of fat distribution. Nurses need to be skilled in the use of the equipment and familiar with the techniques. PMID:21876958

  7. [Possible methods for evaluating bone density in the maxillofacial region].

    PubMed

    Koppány, Ferenc; Joób-Fancsaly, Arpád; Szabo, György

    2007-04-01

    Bone densitometry is a commonly used procedure in general medicine to measure the mineral content of the bone. The method helps in establishing an early diagnosis of metabolic diseases of the bone (especially osteoporosis), which decreases the incidence of pathological fractures in a high degree. Recent studies have shown that significant correlation can be found between the optical densitometric evaluations of the jaws and the densitometric figures of other bones of the skeleton (spine, hip). These results point out the possible role of the dentist in the early diagnosis of osteoporosis. The recent methods in general medicine are based on the measurement of photon and x-ray absorption followed by computerized analysis (single photon absorptiometry, single energy x-ray absorptiometry, dual photon absorptiometry, dual energy x-ray absorptiometry). Besides the previously mentioned techniques ultrasound attenuation detection (quantitative ultrasound) and computed tomographic approaches are also widely spread. Methods utilizing the developed panoramic x-ray films are also being used for densitometric evaluations. The results given by these measurements seem to be promising as a unique detection of the early signs of osteoporosis. PMID:17546899

  8. The Effect of the Lumbar Vertebral Malpositioning on Bone Mineral Density Measurements of the Lumbar Spine by Dual-Energy X-Ray Absorptiometry.

    PubMed

    Izadyar, Sina; Golbarg, Shima; Takavar, Abbas; Zakariaee, Seyed Salman

    2016-01-01

    A significant discrepancy between the results of previous human and phantoms studies is identified regarding the effects of vertebral positioning on bone mineral density (BMD) measurements. We aimed to evaluate the effects of lumbar vertebral positioning on BMD measurements by dual-energy X-ray absorptiometry in a human cadaveric spine phantom. A spine phantom was designed using L1-L4 vertebrae harvested from a 48-year-old male cadaver without coronal or sagittal deformity. The spine phantom was scanned by DEXXUM T bone densitometer in a constant scanning speed of 30 mm/s and resolution of 1.0 × 1.0 mm. BMD values were measured in a positive and negative lumbar lordosis and kyphosis tilt angles in the sagittal plane, from 0° to 35°, with 7° increments. Also BMD values were measured in axial and lateral rotations with 5° increments. Projectional dual-energy X-ray absorptiometry measurements are significantly affected by positioning of the lumbar spine, more severely affected by kyphotic curvature, but also by axial and lateral rotational scoliosis as well as lordotic curvature. Increasing the severity of lordosis and kyphosis curvatures leads to false reduction of BMD value up to 17.5% and 11.5%, respectively. Increasing the degree of lateral and axial rotational scolioses results in a false decrease in BMD measurements by up to 10.8% and 9.6%, respectively. To achieve the most accurate scanning results, error sources and abnormal positioning should be identified and minimized as much as possible. If not correctable, they should be taken into consideration while interpreting the results. PMID:26778450

  9. Dual Energy X-Ray Absorptiometry of the Distal Femur May Be More Reliable than the Proximal Tibia in Spinal Cord Injury

    PubMed Central

    Morse, Leslie R.; Lazzari, Antonio A.; Battaglino, Ricardo; Stolzmann, Kelly L.; Matthess, Kirby R.; Gagnon, David R.; Davis, Samuel A.; Garshick, Eric

    2009-01-01

    Objective Although spinal cord injury frequently results in low impact fractures at the distal femur and proximal tibia, there are no standard clinical protocols for assessing bone mineral density at these sites. We evaluated the precision of dual energy x-ray absorptiometry scanning at two skeletal sites at the knee (proximal femur and distal tibia) in individuals with spinal cord injury. Design Cross-sectional. Setting VA Medical Center. Participants 20 subjects with chronic SCI. Interventions Not Applicable. Main Outcome Measures Precision as determined by root mean square coefficient of variation (RMS-CV) and root mean standard deviation (RMS-SD). Results At the distal femur the root RMS-CV was 3.01% and the RMS-SD was 0.025 g/cm2. At the proximal tibia the RMS-CV was 5.91% and the RMS-SD was 0.030 g/cm2. Conclusions Precision at the distal femur is greater than the proximal tibia and we recommend it as the preferred site for the longitudinal assessment of bone mineral density at the knee in chronic spinal cord injury. PMID:19406303

  10. Evaluation of the effects of hypergravity exposure and caging restraint on bone mineralization in the Beagle by in vivo photon absorptiometry

    NASA Technical Reports Server (NTRS)

    Fisher, G. L.; Berding, K. L.; Goldman, M.

    1975-01-01

    Photon absorptiometry was used to evaluate bone mineral kinetics associated with normal development and the possible perturbations to bone development resulting from hypergravity exposure over a period of six months in developing Beagles. A series of seven measurements were performed at specific times with the first measurement prior to treatment and subsequent measurements at 2, 5, 9, 14, 20 and 26 weeks from the onset of the experiment. Four groups of six male Beagle pups, ranging in age from 85 to 92 days were studied. Two groups were chronically exposed to hypergravity treatments by centrifugation of 2.0 G (18.0 RPM, 11.7 ft radius) and 2.6 G (18.0 RPM, 19.8 ft radius) for the 26 week period. A third group of six dogs served as a caged control to evaluate possible changes due to confinement in small plexiglass cages similar to those of the centrifuge. Thus this control group was subjected to limited exercise due to caging restraint. The fourth group of animals was housed in open runs to allow exercise without the spatial confinement of the smaller plexiglass cages. Results show highly significant differences in body weight, bone length, increase in bone density of control group relative to other groups, and a decrease in bone mineral content in the two gravity treated groups.

  11. Skeletal status and soft tissue composition in astronauts. Tissue and fluid changes by radionuclide absorptiometry in vivo

    NASA Technical Reports Server (NTRS)

    Cameron, J. R.; Mazess, R. B.; Wilson, C. R.

    1974-01-01

    Research on the measurement of bone mineral content and body composition ranges from isotopic tracer methods and the adoption of clinical standards to osteoporosis therapy and the effects of nutritional factors on bone loss.

  12. Using Magnetic Resonance for Predicting Femoral Strength: Added Value with respect to Bone Densitometry

    PubMed Central

    Louis, Olivia; Fierens, Yves; Strantza, Maria; Luypaert, Robert; de Mey, Johan; Cattrysse, Erik

    2015-01-01

    Background and Purpose. To evaluate the added value of MRI with respect to peripheral quantitative computed tomography (pQCT) and dual energy X-ray absorptiometry (DXA) for predicting femoral strength. Material and Methods. Bone mineral density (BMD) of eighteen femur specimens was assessed with pQCT, DXA, and MRI (using ultrashort echo times (UTE) and the MicroView software). Subsequently biomechanical testing was performed to assess failure load. Simple and multiple linear regression were used with failure load as the dependent variable. Results. Simple linear regression allowed a prediction of failure load with either pQCT, DXA, or MRI in an r2 range of 0.41–0.48. Multiple linear regression with pQCT, DXA, and MRI yielded the best prediction (r2 = 0.68). Conclusions. The accuracy of MRI, using UTE and MicroView software, to predict femoral strength compares well with that of pQCT or DXA. Furthermore, the inclusion of MRI in a multiple-regression model yields the best prediction. PMID:26413544

  13. Evaluation of growth patterns and body composition in C57Bl/6J mice using dual energy X-ray absorptiometry.

    PubMed

    Gargiulo, Sara; Gramanzini, Matteo; Megna, Rosario; Greco, Adelaide; Albanese, Sandra; Manfredi, Claudio; Brunetti, Arturo

    2014-01-01

    The normal growth pattern of female C57BL/6J mice, from 5 to 30 weeks of age, has been investigated in a longitudinal study. Weight, body surface area (BS), and body mass index (BMI) were evaluated in forty mice. Lean mass and fat mass, bone mineral content (BMC), and bone mineral density (BMD) were monitored by dual energy X-ray absorptiometry (DEXA). Weight and BS increased linearly (16.15 ± 0.64-27.64 ± 1.42 g; 51.13 ± 0.74-79.57 ± 2.15 cm(2), P < 0.01), more markedly from 5 to 9 weeks of age (P < 0.001). BMD showed a peak at 17 weeks (0.0548 ± 0.0011 g/cm(2) ∗ m, P < 0.01). Lean mass showed an evident gain at 9 (15.8 ± 0.8 g, P < 0.001) and 25 weeks (20.5 ± 0.3 g, P < 0.01), like fat mass from 13 to 17 weeks (2.0 ± 0.4-3.6 ± 0.7 g, P < 0.01). BMI and lean mass index (LMI) reached the highest value at 21 weeks (3.57 ± 0.02-0.284 ± 0.010 g/cm(2), resp.), like fat mass index (FMI) at 17 weeks (0.057 ± 0.009 g/cm(2)) (P < 0.01). BMI, weight, and BS showed a moderate positive correlation (0.45-0.85) with lean mass from 5 to 21 weeks. Mixed linear models provided a good prediction for lean mass, fat mass, and BMD. This study may represent a baseline reference for a future comparison of wild-type C57BL/6J mice with models of altered growth. PMID:25110666

  14. Reproducibility of Vertebral Fracture Assessment Readings From Dual-energy X-ray Absorptiometry in Both a Population-based and Clinical Cohort: Cohen's and Uniform Kappa.

    PubMed

    Aubry-Rozier, Bérengère; Chapurlat, Roland; Duboeuf, François; Iglesias, Katia; Krieg, Marc-Antoine; Lamy, Olivier; Burnand, Bernard; Hans, Didier

    2015-01-01

    Vertebral fracture assessments (VFAs) using dual-energy X-ray absorptiometry increase vertebral fracture detection in clinical practice and are highly reproducible. Measures of reproducibility are dependent on the frequency and distribution of the event. The aim of this study was to compare 2 reproducibility measures, reliability and agreement, in VFA readings in both a population-based and a clinical cohort. We measured agreement and reliability by uniform kappa and Cohen's kappa for vertebral reading and fracture identification: 360 VFAs from a population-based cohort and 85 from a clinical cohort. In the population-based cohort, 12% of vertebrae were unreadable. Vertebral fracture prevalence ranged from 3% to 4%. Inter-reader and intrareader reliability with Cohen's kappa was fair to good (0.35-0.71 and 0.36-0.74, respectively), with good inter-reader and intrareader agreement by uniform kappa (0.74-0.98 and 0.76-0.99, respectively). In the clinical cohort, 15% of vertebrae were unreadable, and vertebral fracture prevalence ranged from 7.6% to 8.1%. Inter-reader reliability was moderate to good (0.43-0.71), and the agreement was good (0.68-0.91). In clinical situations, the levels of reproducibility measured by the 2 kappa statistics are concordant, so that either could be used to measure agreement and reliability. However, if events are rare, as in a population-based cohort, we recommend evaluating reproducibility using the uniform kappa, as Cohen's kappa may be less accurate. PMID:25439454

  15. Calcification content quantification by dual-energy x-ray absorptiometry with a 2D digital radiographic detector

    NASA Astrophysics Data System (ADS)

    Dinten, Jean M.; Robert-Coutant, Christine; Darboux, Michel; Gonon, Georges; Bordy, Thomas

    2003-06-01

    In a previous paper (SPIE Medical Imaging 2001), a dual energy method for bone densitometry using a 2D digital radiographic detector has been presented. In this paper, calcium content quantification performance of the approach is precised. The main challenge is to achieve quantification using scatter-corrected dual energy acquisitions. Therefore a scatter estimation approach, based on an expression of scatter as a functional of the primary flux, has been developed. This expression is derived from the Klein and Nishina equation and includes tabulated scatter level values. The calcium quantification performances are validated on two configurations. A first one is issued from criteria developed by the French "Groupe de Recherche et d'Information sur les Osteoporoses." It is based on the use of a phantom made of five 3mm thick PVC sheets in the form of five steps, representing five different bone mineral density values, included in a lucite container filled with water. Additional lucite plates can be put over the phantom. This phantom has been used for evaluation of quantification robustness versus patient thickness and composition variations, and for accuracy evaluation. The second configuration, composed of small calcified objects (representative of lung nodules), is used for evaluating capacities to differentiate calcified from non calcified nodules and to test calcium content quantification performance.

  16. X-ray scatter correction for dual-energy x-ray absorptiometry: compensation of patient's lean/fat composition

    NASA Astrophysics Data System (ADS)

    Dinten, Jean-Marc; Darboux, Michel; Bordy, Thomas; Robert-Coutant, Christine; Gonon, Georges

    2004-05-01

    At CEA-LETI, a DEXA approach for systems using a digital 2D radiographic detector has been developed. It relies on an original X-rays scatter management method, based on a combined use of an analytical model and of scatter calibration data acquired through different thicknesses of Lucite slabs. Since Lucite X-rays interaction properties are equivalent to fat, the approach leads to a scatter flux map representative of a 100% fat region. However, patients" soft tissues are composed of lean and fat. Therefore, the obtained scatter map has to be refined in order to take into account the various fat ratios that can present patients. This refinement consists in establishing a formula relating the fat ratio to the thicknesses of Low and High Energy Lucite slabs leading to same signal level. This proportion is then used to compute, on the basis of X-rays/matter interaction equations, correction factors to apply to Lucite equivalent X-rays scatter map. Influence of fat ratio correction has been evaluated, on a digital 2D bone densitometer, with phantoms composed of a PVC step (simulating bone) and different Lucite/water thicknesses as well as on patients. The results show that our X-rays scatter determination approach can take into account variations of body composition.

  17. Bone mineral density test

    MedlinePlus

    BMD test; Bone density test; Bone densitometry; DEXA scan; DXA; Dual-energy x-ray absorptiometry; p-DEXA; Osteoporosis-BMD ... need to undress. This scan is the best test to predict your risk of fractures. Peripheral DEXA ( ...

  18. Evaluation of Growth Patterns and Body Composition in C57Bl/6J Mice Using Dual Energy X-Ray Absorptiometry

    PubMed Central

    Albanese, Sandra; Manfredi, Claudio; Brunetti, Arturo

    2014-01-01

    The normal growth pattern of female C57BL/6J mice, from 5 to 30 weeks of age, has been investigated in a longitudinal study. Weight, body surface area (BS), and body mass index (BMI) were evaluated in forty mice. Lean mass and fat mass, bone mineral content (BMC), and bone mineral density (BMD) were monitored by dual energy X-ray absorptiometry (DEXA). Weight and BS increased linearly (16.15 ± 0.64–27.64 ± 1.42 g; 51.13 ± 0.74–79.57 ± 2.15 cm2, P < 0.01), more markedly from 5 to 9 weeks of age (P < 0.001). BMD showed a peak at 17 weeks (0.0548 ± 0.0011 g/cm2∗ m, P < 0.01). Lean mass showed an evident gain at 9 (15.8 ± 0.8 g, P < 0.001) and 25 weeks (20.5 ± 0.3 g, P < 0.01), like fat mass from 13 to 17 weeks (2.0 ± 0.4–3.6 ± 0.7 g, P < 0.01). BMI and lean mass index (LMI) reached the highest value at 21 weeks (3.57 ± 0.02–0.284 ± 0.010 g/cm2, resp.), like fat mass index (FMI) at 17 weeks (0.057 ± 0.009 g/cm2) (P < 0.01). BMI, weight, and BS showed a moderate positive correlation (0.45–0.85) with lean mass from 5 to 21 weeks. Mixed linear models provided a good prediction for lean mass, fat mass, and BMD. This study may represent a baseline reference for a future comparison of wild-type C57BL/6J mice with models of altered growth. PMID:25110666

  19. PRECISION OF SINGLE VERSUS BILATERAL HIP BONE MINERAL DENSITY SCANS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dual-energy X-ray absorptiometry (DXA) scans of the hip and lumbar spine are currently the "gold standard" for measurement of bone mineral density (BMD). DXA allows swift, noninvasive measurements with minimal radiation for both clinical practice and research. Traditional testing has used results ...

  20. A device for in vivo measurements of quantitative ultrasound variables at the human proximal femur.

    PubMed

    Barkmann, Reinhard; Laugier, Pascal; Moser, Urs; Dencks, Stefanie; Klausner, Michael; Padilla, Frédéric; Haïat, Guilleaume; Glüer, Claus-C

    2008-01-01

    Quantitative ultrasound (QUS) at the calcaneus has similar power as a bone mineral density (BMD)- measurement using DXA for the prediction of osteoporotic fracture risk. Ultrasound equipment is less expensive than DXA and free of ionizing radiation. As a mechanical wave, QUS has the potential of measuring different bone properties than dual X-ray absorptiometry (DXA,) which depends on X-ray attenuation and might be developed into a tool of comprehensive assessment of bone strength. However, site-specific DXA at the proximal femur shows best performance in the prediction of hip fractures. To combine the potential of QUS with measurements directly at the femur, we developed a device for in vivo QUS measurements at this site. Methods comprise ultrasound transmission through the bone, reflection from the bone surface, and backscatter from the inner trabecular structure. The complete area of the proximal femur can be scanned except at the femoral head, which interferes with the ilium. To avoid edge artifacts, a subregion of the proximal femur in the trochanteric region was selected as measurement region. First, in vivo measurements demonstrate a good signal to noise ratio and proper depiction of the proximal femur on an attenuation image. Our results demonstrate the feasibility of in vivo measurements. Further improvements can be expected by refinement of the scanning technique and data evaluation method to enhance the potential of the new method for the estimation of bone strength. PMID:18599408

  1. Use of prediction equations to determine the accuracy of whole-body fat and fat-free mass and appendicular skeletal muscle mass measurements from a single abdominal image using computed tomography in advanced cancer patients.

    PubMed

    Kilgour, Robert D; Cardiff, Katrina; Rosenthall, Leonard; Lucar, Enriqueta; Trutschnigg, Barbara; Vigano, Antonio

    2016-01-01

    Measurements of body composition using dual-energy X-ray absorptiometry (DXA) and single abdominal images from computed tomography (CT) in advanced cancer patients (ACP) have important diagnostic and prognostic value. The question arises as to whether CT scans can serve as surrogates for DXA in terms of whole-body fat-free mass (FFM), whole-body fat mass (FM), and appendicular skeletal muscle (ASM) mass. Predictive equations to estimate body composition for ACP from CT images have been proposed (Mourtzakis et al. 2008; Appl. Physiol. Nutr. Metabol. 33(5): 997-1006); however, these equations have yet to be validated in an independent cohort of ACP. Thus, this study evaluated the accuracy of these equations in estimating FFM, FM, and ASM mass using CT images at the level of the third lumbar vertebrae and compared these values with DXA measurements. FFM, FM, and ASM mass were estimated from the prediction equations proposed by Mourtzakis and colleagues (2008) using single abdominal CT images from 43 ACP and were compared with whole-body DXA scans using Spearman correlations and Bland-Altman analyses. Despite a moderate to high correlation between the actual (DXA) and predicted (CT) values for FM (rho = 0.93; p ≤ 0.001), FFM (rho = 0.78; p ≤ 0.001), and ASM mass (rho = 0.70; p ≤ 0.001), Bland-Altman analyses revealed large range-of-agreement differences between the 2 methods (29.39 kg for FFM, 15.47 kg for FM, and 3.99 kg for ASM mass). Based on the magnitude of these differences, we concluded that prediction equations using single abdominal CT images have poor accuracy, cannot be considered as surrogates for DXA, and may have limited clinical utility. PMID:26695688

  2. Gender Differences in Assessment of Obesity in Rheumatoid Arthritis

    PubMed Central

    PKatz, Patricia; Yazdany, Jinoos; Trupin, Laura; Schmajuk, Garbriela; Margaretten, Mary; Criswell, Lindsey A.; Yelin, Edward H.

    2012-01-01

    Objective Determine prevalence of obesity and how accurately standard anthropometric measures identify obesity among men and women with RA. Methods Dual-energy x-ray absorptiometry (DXA) was performed for 141 persons with RA (56 men, 85 women). Two anthropometric proxies of obesity (body mass index [BMI], waist circumference [WC]) were compared to a DXA-based obesity criterion. Receiver operating characteristic (ROC) curves determined optimal cut-points for each anthropometric measure, relative to DXA. Association of body fat and anthropometric obesity measures with disease status and cardiovascular risk was assessed in multiple regression analyses, controlling for age and glucocorticoid use. All analyses were performed separately for men and women. Results 20%, 32%, and 44% of women, and 41%, 36%, and 80% of men were classified as obese by BMI, WC, and DXA, respectively. Cut-points were identified for anthropometric measures to better approximate DXA estimates of percent body fat (BMI: women, ≥26.1 kg/m2; men ≥24.7 kg/m2. WC: women, ≥83 cm; men, ≥96 cm). For women and men, higher % fat was associated with poorer RA status. Anthropometric measures were more closely linked to RA status for women, but identified cardiovascular risk for both women and men. Conclusions A large percentage of this RA sample was overfat; DXA-defined obesity was twice as common in men than in women. Utility of revised BMI and WC cut-points compared to traditional cut-points remains to be examined in prospective studies, but results suggest that lower, sex-specific cut-points may be warrented to better identify individuals at risk for poor RA and/or cardiovascular outcomes. PMID:22833513

  3. Instrumental diagnosis of osteoporosis.

    PubMed

    Rossini, M; Viapiana, O; Adami, S

    1998-06-01

    Considerable progress in the development of methods for assessing the skeleton now makes it possible to detect osteoporosis non-invasively and early. There is a variety of techniques available at present: single-photon (SPA) and single X-ray absorptiometry (SXA), dual-photon (DPA) and dual X-ray absorptiometry (DXA), quantitative computed tomography (QCT), radiographic absorptiometry (RA), and quantitative ultrasound (QUS), and their development has certainly been driven by the need to overcome the inherent shortcomings of plain radiography for this purpose. Both SPA and SXA methods make a quantitative assessment of the bone mineral content (BMC) or density (BMD) at peripheral sites of the skeleton possible. Single energy measurements are not possible at sites with variable soft tissue thickness and composition, i.e., the axial skeleton. For these purposes, DPA and DXA techniques were introduced. The main advantages of an X-ray system over a radionuclide system are shortened examination time, greater accuracy and precision limited to higher resolution, and removal of errors due to source decay correction. Low radiation dose, availability, capacity to evaluate multiple sites, and ease of use have made DXA the most widely used technique for measuring bone mineral density. QCT can determine the true volumetric density of trabecular or cortical bone in three dimensions at any skeletal site. Recently developed new computer-assisted methods have improved RA precision, thus providing a simple and inexpensive technique for screening of bone mineral status of large populations. QUS was reported to provide information regarding the structural characteristics of bone, which may be relevant to the appearance of osteoporotic fractures; indeed, some studies suggest a relationship between QUS and bone strength beyond that which can be explained by BMD. Recent experimental studies suggested that magnetic resonance might also constitute a promising tool for assessing osteoporosis

  4. Accuracy of Body Mass Index Cutoffs for Classifying Obesity in Chilean Children and Adolescents

    PubMed Central

    Gómez-Campos, Rossana; David Langer, Raquel; de Fátima Guimarães, Roseane; Contiero San Martini, Mariana; Cossio-Bolaños, Marco; de Arruda, Miguel; Guerra-Júnior, Gil; Moreira Gonçalves, Ezequiel

    2016-01-01

    Objective: To determine the accuracy of two international Body Mass Index (BMI) cut-offs for classifying obesity compared to the percentage of fat mass (%FM) assessed by Dual-Energy X-ray Absorptiometry (DXA) in a Chilean sample of children and adolescents; Material and Methods: The subjects studied included 280 children and adolescents (125 girls and 155 boys) aged 8 to 17 years. Weight and height were measured. The BMI was calculated. Two international references (IOFT and WHO) were used as cut-off points. The %FM was assessed by DXA. The receiver operating characteristic (ROC) curve was used to assess the performance of BMI in detecting obesity on the basis of %FM; Results: A high correlation was observed between the %FM measured by the DXA and the Z-scores of IOTF and WHO scores in the Chilean adolescents separated by sex (r = 0.78–0.80). Differences occurred in both references (IOFT and WHO) in relation to the criteria (p < 0.001). Both references demonstrated a good ability to predict sensitivity (between 84% and 93%) and specificity (between 83% and 88%) in both sexes of children and adolescents; Conclusions: A high correlation was observed between the Z-score of the BMI with the percentage of fat determined by the DXA. Despite this, the classifications using the different BMI cut-off points showed discrepancies. This suggests that the cut-off points selected to predict obesity in this sample should be viewed with caution. PMID:27164119

  5. How well do skinfold equations predict percent body fat in elite soccer players?

    PubMed

    Reilly, T; George, K; Marfell-Jones, M; Scott, M; Sutton, L; Wallace, J A

    2009-08-01

    The use of generic equations for estimating percent body fat from skinfold thicknesses can be criticised when applied to specific sports. The present aims were to compare existing methods of using skinfold data and to derive an equation for predicting body fat values in professional soccer players. Forty-five professional soccer players (24.2 +/- 5.0 years; 82.0 +/- 8.5 kg; 1.82 +/- 0.07 m) participated. Skinfold thicknesses were assessed at eight sites for the application of existing prediction equations. Skinfold data were also utilised to determine a novel soccer-specific equation. All players had a reference estimate of percent fat by dual-energy x-ray absorptiometry (DXA). The existing skinfold equations differed from the DXA-referenced values by varying degrees, the equation of Withers et al. (1987) demonstrating the lowest bias and highest relationship and agreement with DXA. Regression analysis resulted in an equation incorporating anterior thigh, abdominal, triceps and medial calf sites, accounting for 78.4% variance in DXA criterion values. PMID:19301213

  6. A systematic quality assurance study in bone densitometry devices

    NASA Astrophysics Data System (ADS)

    Tuncman, Duygu; Kovan, Hatice; Kovan, Bilal; Demir, Bayram; Turkmen, Cuneyt

    2015-07-01

    Osteoporosis is the most common metabolic bone disease and can result in devastating physical, psychosocial, and economic consequences. It occurs in women after menopause and affects most elderly. Dual-energy x-ray absorptiometry (DXA) is currently the most widely used method for the measurement of areal Bone Mineral Density (BMD) (g/cm2) .DXA is based on the variable absorption of X-ray by the different body components and uses high and low energy X-ray photons. There are two important values in the assessment of the DXA. These values are T-score and Z-score. The T-score is calculated by taking the difference between a patient's measured BMD with the mean BMD of the young normal population, matched for gender and ethnicity, and then by dividing the difference with the standard deviation (SD) of the BMD of the young normal population. T-score and also Z-score are directly depends on the Bone Mineral Density (BMD). BMD measurements should be made periodically in a patient life. But mostly, it is not possible with the same device. Therefore, in this study, for the quality assurance of bone densitometry devices, we evaluated the BMD results measured in the different Bone Densitometry (DXA) devices using a spine phantom.

  7. Effect of hydroxyapatite-coated tibial components on changes in bone mineral density of the proximal tibia after uncemented total knee arthroplasty: a prospective randomized study using dual-energy x-ray absorptiometry.

    PubMed

    Petersen, Michael M; Gehrchen, P Martin; Ostgaard, Svend E; Nielsen, Palle K; Lund, Bjarne

    2005-06-01

    Sixteen patients scheduled for an uncemented total knee arthroplasty (TKA) were randomized to receive a tibial component either with (n = 8) or without (n = 8) hydroxyapatite (HA) coating. In 4 regions of interest, prospective measurements of bone mineral density (BMD) using dual-energy x-ray absorptiometry were performed in the proximal tibia. Two years after the operation, the only significant change in BMD was in the lateral tibial condyle, where BMD had increased by 6.1% (95% confidence interval: 2.3%-9.9%) in patients with tibial components without HA. The intragroup changes (0-24 months) in the uncoated group and HA-coated group were significantly different (P = .003) in these regions of interest. There was no significant effect of HA coating on bone remodeling pattern of the proximal tibia. PMID:16124970

  8. Application of a model based on dual-energy X-ray absorptiometry and finite element simulation for predicting the probability of osteoporotic hip fractures to a sample of people over 60 years.

    PubMed

    López, Enrique; Casajús, José A; Ibarz, Elena; Gómez-Cabello, Alba; Ara, Ignacio; Vicente-Rodríguez, Germán; Mateo, Jesús; Herrera, Antonio; Gracia, Luis

    2015-05-01

    The aim of this work is the application of a mechanical predictive model to a sample of people over 60 years of age, in order to analyze the fracture probability related to age and sex. A total of 223 elderly people (63 men, aged 63-88, 72.32±6.10; 157 women, aged 61-89, 73.28±5.73) participated in the study. A dual-energy X-ray absorptiometry scanner was used to measure the bone mineral content and bone mineral density at total hip and femoral neck. The application of the predictive model also required a finite element simulation of the proximal femur, obtaining the mechanical damage and fracture probability maps corresponding to each sex and age groups analyzed. Statistical analysis shows higher values of bone mineral density, and consequently of Young's modulus, for men than for women. In general, a decrease of BMD is observed since 65 years old. The maximum mechanical damage value is always located at the femoral neck. The results indicate that mechanical damage tends to increase with age. Coherently with mechanical damage, the maximum fracture probability value is always located at the femoral neck and tends to increase with age. The simulation model to determine the probability of fracture is more complete than the simple measurement of bone mineral density, because provides additional information about mechanical properties of bone, and allows for a prospective detection of fracture risk. The model may be used for risk evaluation in specific patients, if anatomical and dual-energy X-ray absorptiometry measurements are available, helping us to decide about preventive pharmacological treatment for hip fracture. PMID:25963384

  9. Osteoporosis services in secondary care: a UK survey.

    PubMed Central

    Rowe, R E; Cooper, C C

    2000-01-01

    A 1994 survey indicated that only 13 health authorities in the UK were purchasing access to dual X-ray absorptiometry (DXA), the most accurate measure of osteoporosis risk. By 1998 the number of centres (including private facilities providing DXA) was 161. All these were sent a questionnaire concerning their activities. 124 (77%) responded, and the survey found that DXA machines operate, on average, for only 3.6 days a week. Funding of and access to diagnostic services for osteoporosis varies greatly. There is clear scope for greater efficiency in the use of existing DXA machines and more equitable access to diagnostic services is required for effective management of osteoporosis. PMID:10700842

  10. Contemporary methods of body composition measurement.

    PubMed

    Fosbøl, Marie Ø; Zerahn, Bo

    2015-03-01

    Reliable and valid body composition assessment is important in both clinical and research settings. A multitude of methods and techniques for body composition measurement exist, all with inherent problems, whether in measurement methodology or in the assumptions upon which they are based. This review is focused on currently applied methods for in vivo measurement of body composition, including densitometry, bioimpedance analysis, dual-energy X-ray absorptiometry, computed tomography (CT), magnetic resonance techniques and anthropometry. Multicompartment models including quantification of trace elements by in vivo neutron activation analysis, which are regarded as gold standard methods, are also summarized. The choice of a specific method or combination of methods for a particular study depends on various considerations including accuracy, precision, subject acceptability, convenience, cost and radiation exposure. The relative advantages and disadvantages of each method are discussed with these considerations in mind. PMID:24735332

  11. Improving bone strength prediction in human proximal femur specimens through geometrical characterization of trabecular bone microarchitecture and support vector regression

    PubMed Central

    Huber, Markus B.; Carballido-Gamio, Julio; Bauer, Jan S.; Baum, Thomas; Eckstein, Felix; Lochmüller, Eva; Majumdar, Sharmila; Link, Thomas M.; Wismüller, Axel

    2014-01-01

    We investigate the use of different trabecular bone descriptors and advanced machine learning tech niques to complement standard bone mineral density (BMD) measures derived from dual-energy x-ray absorptiometry (DXA) for improving clinical assessment of osteoporotic fracture risk. For this purpose, volumes of interest were extracted from the head, neck, and trochanter of 146 ex vivo proximal femur specimens on multidetector computer tomography. The trabecular bone captured was characterized with (1) statistical moments of the BMD distribution, (2) geometrical features derived from the scaling index method (SIM), and (3) morphometric parameters, such as bone fraction, trabecular thickness, etc. Feature sets comprising DXA BMD and such supplemental features were used to predict the failure load (FL) of the specimens, previously determined through biomechanical testing, with multiregression and support vector regression. Prediction performance was measured by the root mean square error (RMSE); correlation with measured FL was evaluated using the coefficient of determination R2. The best prediction performance was achieved by a combination of DXA BMD and SIM-derived geometric features derived from the femoral head (RMSE: 0.869 ± 0.121, R2: 0.68 ± 0.079), which was significantly better than DXA BMD alone (RMSE: 0.948 ± 0.119, R2: 0.61 ± 0.101) (p < 10−4). For multivariate feature sets, SVR outperformed multiregression (p < 0.05). These results suggest that supplementing standard DXA BMD measurements with sophisticated femoral trabecular bone characterization and supervised learning techniques can significantly improve biomechanical strength prediction in proximal femur specimens. PMID:24860245

  12. Texture analysis of clinical radiographs using radon transform on a local scale for differentiation between post-menopausal women with and without hip fracture

    NASA Astrophysics Data System (ADS)

    Boehm, Holger F.; Körner, Markus; Baumert, Bernhard; Linsenmaier, Ulrich; Reiser, Maximilian

    2011-03-01

    Osteoporosis is a chronic condition characterized by demineralization and destruction of bone tissue. Fractures associated with the disease are becoming an increasingly relevant issue for public health institutions. Prediction of fracture risk is a major focus research and, over the years, has been approched by various methods. Still, bone mineral density (BMD) obtained by dual-energy X-ray absorptiometry (DXA) remains the clinical gold-standard for diagnosis and follow-up of osteoporosis. However, DXA is restricted to specialized diagnostic centers and there exists considerable overlap in BMD results between populations of individuals with and without fractures. Clinically far more available than DXA is conventional x-ray imaging depicting trabecular bone structure in great detail. In this paper, we demonstrate that bone structure depicted by clinical radiographs can be analysed quantitatively by parameters obtained from the Radon Transform (RT). RT is a global analysis-tool for detection of predefined, parameterized patterns, e.g. straight lines or struts, representing suitable approximations of trabecular bone texture. The proposed algorithm differentiates between patients with and without fractures of the hip by application of various texture-metrics based on the Radon-Transform to standard x-ray images of the proximal femur. We consider three different regions-of-interest in the proximal femur (femoral head, neck, and inter-trochanteric area), and conduct an analysis with respect to correct classification of the fracture status. Performance of the novel approach is compared to DXA. We draw the conclusion that performance of RT is comparable to DXA and may become a useful supplement to densitometry for the prediction of fracture risk.

  13. Validity of Bioelectrical Impedance Analysis to Estimation Fat-Free Mass in the Army Cadets

    PubMed Central

    Langer, Raquel D.; Borges, Juliano H.; Pascoa, Mauro A.; Cirolini, Vagner X.; Guerra-Júnior, Gil; Gonçalves, Ezequiel M.

    2016-01-01

    Background: Bioelectrical Impedance Analysis (BIA) is a fast, practical, non-invasive, and frequently used method for fat-free mass (FFM) estimation. The aims of this study were to validate predictive equations of BIA to FFM estimation in Army cadets and to develop and validate a specific BIA equation for this population. Methods: A total of 396 males, Brazilian Army cadets, aged 17–24 years were included. The study used eight published predictive BIA equations, a specific equation in FFM estimation, and dual-energy X-ray absorptiometry (DXA) as a reference method. Student’s t-test (for paired sample), linear regression analysis, and Bland–Altman method were used to test the validity of the BIA equations. Results: Predictive BIA equations showed significant differences in FFM compared to DXA (p < 0.05) and large limits of agreement by Bland–Altman. Predictive BIA equations explained 68% to 88% of FFM variance. Specific BIA equations showed no significant differences in FFM, compared to DXA values. Conclusion: Published BIA predictive equations showed poor accuracy in this sample. The specific BIA equations, developed in this study, demonstrated validity for this sample, although should be used with caution in samples with a large range of FFM. PMID:26978397

  14. Fracture Prediction After Discontinuation of 4 to 5 Years of Alendronate Therapy

    PubMed Central

    Bauer, Douglas C.; Schwartz, Ann; Palermo, Lisa; Cauley, Jane; Hochberg, Marc; Santora, Art; Cummings, Steven R.; Black, Dennis M.

    2015-01-01

    IMPORTANCE Discontinuation of bisphosphonate therapy after 3 to 5 years is increasingly considered, but methods to monitor fracture risk after discontinuation have not been established. OBJECTIVE To test methods of predicting fracture risk among women who have discontinued alendronate therapy after 4 to 5 years. DESIGN, SETTING, AND PARTICIPANTS The prospective Fracture Intervention Trial Long-term Extension (FLEX) study randomized postmenopausal women aged 61 to 86 years previously treated with 4 to 5 years of alendronate therapy to 5 more years of alendronate or placebo from 1998 through 2003; the present analysis includes only the placebo group. Hip and spine dual-energy x-ray absorptiometry (DXA) were measured when placebo was begun (FLEX baseline) and after 1 to 3 years of follow-up. Two biochemical markers of bone turnover, urinary type 1 collagen cross-linked N-telopeptide (NTX) and serum bone-specific alkaline phosphatase (BAP), were measured at FLEX baseline and after 1 and 3 years. MAIN OUTCOMES AND MEASURES Symptomatic spine and nonspine fractures occurring after the follow-up measurement of DXA or bone turnover. RESULTS During 5 years of placebo, 94 of 437 women (22%) experienced 1 or more symptomatic fractures; 82 had fractures after 1 year. One-year changes in hip DXA, NTX, and BAP were not related to subsequent fracture risk, but older age and lower hip DXA at time of discontinuation were significantly related to increased fracture risk (lowest tertile of baseline femoral neck DXA vs other 2 tertiles relative hazard ratio, 2.17 [95%CI, 1.38–3.41]; total hip DXA relative hazard ratio, 1.87 [95%CI, 1.20–2.92]). CONCLUSIONS AND RELEVANCE Among postmenopausal women who discontinue alendronate therapy after 4 to 5 years, age and hip BMD at discontinuation predict clinical fractures during the subsequent 5 years. Follow-up measurements of DXA 1 year after discontinuation and of BAP or NTX 1 to 2 years after discontinuation are not associated with

  15. Prospective cohort study of spinal muscular atrophy types 2 and 3

    PubMed Central

    Kaufmann, Petra; McDermott, Michael P.; Darras, Basil T.; Finkel, Richard S.; Sproule, Douglas M.; Kang, Peter B.; Oskoui, Maryam; Constantinescu, Andrei; Gooch, Clifton L.; Foley, A. Reghan; Yang, Michele L.; Tawil, Rabi; Chung, Wendy K.; Martens, William B.; Montes, Jacqueline; Battista, Vanessa; O'Hagen, Jessica; Dunaway, Sally; Flickinger, Jean; Quigley, Janet; Riley, Susan; Glanzman, Allan M.; Benton, Maryjane; Ryan, Patricia A.; Punyanitya, Mark; Montgomery, Megan J.; Marra, Jonathan; Koo, Benjamin

    2012-01-01

    Objective: To characterize the natural history of spinal muscular atrophy type 2 and type 3 (SMA 2/3) beyond 1 year and to report data on clinical and biological outcomes for use in trial planning. Methods: We conducted a prospective observational cohort study of 79 children and young adults with SMA 2/3 who participated in evaluations for up to 48 months. Clinically, we evaluated motor and pulmonary function, quality of life, and muscle strength. We also measured SMN2 copy number, hematologic and biochemical profiles, muscle mass by dual x-ray absorptiometry (DXA), and the compound motor action potential (CMAP) in a hand muscle. Data were analyzed for associations between clinical and biological/laboratory characteristics cross-sectionally, and for change over time in outcomes using all available data. Results: In cross-sectional analyses, certain biological measures (specifically, CMAP, DXA fat-free mass index, and SMN2 copy number) and muscle strength measures were associated with motor function. Motor and pulmonary function declined over time, particularly at time points beyond 12 months of follow-up. Conclusion: The intermediate and mild phenotypes of SMA show slow functional declines when observation periods exceed 1 year. Whole body muscle mass, hand muscle compound motor action potentials, and muscle strength are associated with clinical measures of motor function. The data from this study will be useful for clinical trial planning and suggest that CMAP and DXA warrant further evaluation as potential biomarkers. PMID:23077013

  16. Panoramic images of white and black post-menopausal females evidencing carotid calcifications are at high risk of comorbid osteopenia of the femoral neck

    PubMed Central

    Friedlander, AH; Chang, TI; Aghazadehsanai, N; Berenji, GR; Harada, ND; Garrett, NR

    2013-01-01

    Objectives: Femoral neck fractures in older females resulting from decreased bone mineral density (BMD; osteopenia) are associated with increased morbidity and mortality. Bone mineralization inhibition is probably controlled by proteins which also foster vascular calcification. Therefore, we evaluated the relationship between calcified carotid artery plaque (CCAP) on panoramic images and BMD on dual energy X-ray absorptiometry (DXA) bone scans. Methods: Images and hospital records identified by dentists defined two study groups (20 white females and 24 black females) having CCAP and an incidentally obtained bone scan. Ethnically matched (age±7 years, body mass index ±3 units) control groups with panoramic images devoid of CCAP and accompanying DXA scan were likewise constituted. A physician determined the BMD on the DXA. Results: Females with CCAP had significantly (p = 0.03) poorer BMD at the femoral neck than those without CCAP. Although mean femoral neck BMD was significantly lower (p = 0.009) for white than for black females, there was no significant interaction between race and CCAP (p = 0.80). Conclusion: We observed a significant inverse association between the CCAP on panoramic images and femoral neck BMD in post-menopausal white females. PMID:23571481

  17. An Advanced Quantitative Echosound Methodology for Femoral Neck Densitometry.

    PubMed

    Casciaro, Sergio; Peccarisi, Marco; Pisani, Paola; Franchini, Roberto; Greco, Antonio; De Marco, Tommaso; Grimaldi, Antonella; Quarta, Laura; Quarta, Eugenio; Muratore, Maruizio; Conversano, Francesco

    2016-06-01

    The aim of this paper was to investigate the clinical feasibility and the accuracy in femoral neck densitometry of the Osteoporosis Score (O.S.), an ultrasound (US) parameter for osteoporosis diagnosis that has been recently introduced for lumbar spine applications. A total of 377 female patients (aged 61-70 y) underwent both a femoral dual X-ray absorptiometry (DXA) and an echographic scan of the proximal femur. Recruited patients were sub-divided into a reference database used for ultrasound spectral model construction and a study population for repeatability assessments and accuracy evaluations. Echographic images and radiofrequency signals were analyzed through a fully automatic algorithm that performed a series of combined spectral and statistical analyses, providing as a final output the O.S. value of the femoral neck. Assuming DXA as a gold standard reference, the accuracy of O.S.-based diagnoses resulted 94.7%, with k = 0.898 (p < 0.0001). Significant correlations were also found between O.S.-estimated bone mineral density and corresponding DXA values, with r(2) up to 0.79 and root mean square error = 5.9-7.4%. The reported accuracy levels, combined with the proven ease of use and very good measurement repeatability, provide the adopted method with a potential for clinical routine application in osteoporosis diagnosis. PMID:27033331

  18. Body Composition, Muscle Quality and Scoliosis in Female Collegiate Gymnasts: A Pilot Study.

    PubMed

    Trexler, E T; Smith-Ryan, A E; Roelofs, E J; Hirsch, K R

    2015-11-01

    Research has demonstrated an elevated prevalence of body weight concerns and scoliosis among female gymnasts. The purpose of the current pilot study was to evaluate the utility of ultrasonography and dual-energy X-ray absorptiometry (DXA) as practical imaging modalities to measure body composition and spinal curvature variables that may correlate with performance in female collegiate gymnasts (n=15). DXA was used to evaluate body composition and lateral spinal curvature, utilizing a modified Ferguson method. Echo intensity (EI) and cross-sectional area (CSA) of the vastus lateralis were determined from a panoramic cross-sectional ultrasound image. For returning athletes (n=9), performance scores from the previous season were averaged to quantify performance. The average performance score was correlated with lean mass of the arms (R=0.714; P=0.03) and right leg (R=0.680; P=0.04). Performance was not correlated with total mass, fat mass or body fat percentage (P>0.10). Scoliosis was identified in 3 of 15 scans (20%). Echo intensity and CSA of the vastus lateralis were inversely correlated with each other (R=-0.637, P=0.01), but not with other measures of body composition or performance. Results suggest that limb LBM may be a determinant of gymnastics performance, and DXA may provide important health and performance-related information for female collegiate gymnasts. PMID:26332905

  19. Comparison of Gross Body Fat-Water Magnetic Resonance Imaging at 3 Tesla to Dual Energy X-Ray Absorptiometry in Obese Women

    PubMed Central

    Silver, HJ; Niswender, KD; Kullberg, J; Berglund, J; Johansson, L; Bruvold, M; Avison, MJ; Welch, EB.

    2012-01-01

    Improved understanding of how depot-specific adipose tissue mass predisposes to obesity-related comorbidities could yield new insights into the pathogenesis and treatment of obesity as well as metabolic benefits of weight loss. We hypothesized that three-dimensional contiguous “fat-water” MR imaging (FWMRI) covering the majority of a whole-body field of view (FOV) acquired at 3 Tesla (3T) and coupled with automated segmentation and quantification of amount, type and distribution of adipose and lean soft tissue would show great promise in body composition methodology. Precision of adipose and lean soft tissue measurements in body and trunk regions were assessed for 3T FWMRI and compared to DEXA. Anthropometric, FWMRI and DEXA measurements were obtained in twelve women with BMI 30–39.9 kg/m2. Test-retest results found coefficients of variation for FWMRI that were all under 3%: gross body adipose tissue (GBAT) 0.80%, total trunk adipose tissue (TTAT) 2.08%, visceral adipose tissue (VAT) 2.62%, subcutaneous adipose tissue (SAT) 2.11%, gross body lean soft tissue (GBLST) 0.60%, and total trunk lean soft tissue (TTLST) 2.43%. Concordance correlation coefficients between FWMRI and DEXA were 0.978, 0.802, 0.629, and 0.400 for GBAT, TTAT, GBLST and TTLST, respectively. While Bland Altman plots demonstrated agreement between FWMRI and DEXA for GBAT and TTAT, a negative bias existed for GBLST and TTLST measurements. Differences may be explained by the FWMRI FOV length and potential for DEXA to overestimate lean soft tissue. While more development is necessary, the described 3T FWMRI method combined with fully-automated segmentation is fast (<30 minutes total scan and post-processing time), noninvasive, repeatable and cost effective. PMID:23712980

  20. Multiple frequency bioimpedance is an adequate tool to assess total and regional fat mass in HIV-positive patients but not to diagnose HIV-associated lipoatrophy: a pilot study

    PubMed Central

    Pérez-Matute, Patricia; Pérez-Martínez, Laura; Blanco, José R; Ibarra, Valvanera; Metola, Luis; Sanz, Mercedes; Hernando, Luis; Martínez, Sagrario; Ramírez, Arsenio; Ramalle-Gomara, Enrique; Oteo, José A

    2013-01-01

    Introduction HIV-associated lipodystrophy syndrome causes systemic metabolic alterations and psychological distress that worsen the quality of life of these patients. An early detection should be considered to efficiently treat it. Objective criteria or reference indices are needed for an early diagnosis. Bioelectrical Impedance Analysis (BIA) is an operator-independent, repeatable and non-invasive method of body composition evaluation that is less expensive than dual-energy X-ray absorptiometry (DXA) and/or CT scans. The aims of this pilot study were to validate the data obtained by BIA to measure fat mass in HIV-positive patients with/without lipoatrophy and to determine if BIA correctly diagnoses lipoatrophy in HIV-positive patients. Methods Thirty-nine participants were included in this preliminary study. Fourteen were HIV-negative (eight men) whereas 25 were HIV-positive patients (17 men). Eleven of the HIV-positive patients were classified as lipoatrophic according to subjective evaluation by the physicians. Total and regional body composition was measured in basal conditions by DXA and by BIA. To obtain abdominal CT scan fat values, transverse slices with 6-mm thickness were acquired at the L4-L5 intervertebral space. Results BIA measurements of total and regional body fat were significantly correlated with those obtained by DXA (p < 0.05 to <0.01) in HIV-positive patients. However, agreement between methods was poor as not very high ICC (intraclass correlation coefficient) values were observed. BIA and DXA showed higher ICC values in lipoatrophic patients. The visceral index obtained by BIA was correlated with total and visceral fat in L4 measured by CT scan (r = 0.607 and r = 0.617, respectively, p < 0.01) in HIV-positive patients. The Fat Mass Ratio (FMR) calculated by BIA did not correlate or agree with DXA values. Conclusions Multi-frequency BIA could be an effective method to evaluate the evolution of total and regional fat composition in HIV

  1. REVIEW: Development of methods for body composition studies

    NASA Astrophysics Data System (ADS)

    Mattsson, Sören; Thomas, Brian J.

    2006-07-01

    This review is focused on experimental methods for determination of the composition of the human body, its organs and tissues. It summarizes the development and current status of fat determinations from body density, total body water determinations through the dilution technique, whole and partial body potassium measurements for body cell mass estimates, in vivo neutron activation analysis for body protein measurements, dual-energy absorptiometry (DEXA), computed tomography (CT) and magnetic resonance imaging (MRI, fMRI) and spectroscopy (MRS) for body composition studies on tissue and organ levels, as well as single- and multiple-frequency bioimpedance (BIA) and anthropometry as simple easily available methods. Methods for trace element analysis in vivo are also described. Using this wide range of measurement methods, together with gradually improved body composition models, it is now possible to quantify a number of body components and follow their changes in health and disease.

  2. Bone mineral content in early-postmenopausal and postmenopausal osteoporotic women: comparison of measurement methods

    SciTech Connect

    Reinbold, W.D.; Genant, H.K.; Reiser, U.J.; Harris, S.T.; Ettinger, B.

    1986-08-01

    To investigate associations among methods for noninvasive measurement of skeletal bone mass, we studied 40 healthy early postmenopausal women and 68 older postmenopausal women with osteoporosis. Methods included single- and dual-energy quantitative computed tomography (QCT) and dual-photon absorptiometry (DPA) of the lumbar spine, single-photon absorptiometry (SPA) of the distal third of the radius, and combined cortical thickness (CCT) of the second metacarpal shaft. Lateral thoracolumbar radiography was performed, and a spinal fracture index was calculated. There was good correlation between QCT and DPA methods in early postmenopausal women and modest correlation in postmenopausal osteoporotic women. Correlations between spinal measurements (QCT or DPA) and appendicular cortical measurements (SPA or CCT) were modest in healthy women and poor in osteoporotic women. Measurements resulting from one method are not predictive of those by another method for the individual patient. The strongest correlation with severity of vertebral fracture is provided by QCT; the weakest, by SPA. There was a high correlation between single- and dual-energy QCT results, indicating that errors due to vertebral fat are not substantial in these postmenopausal women. Single-energy QCT may be adequate and perhaps preferable for assessing postmenopausal women. The measurement of spinal trabecular bone density by QCT discriminates between osteoporotic women and younger healthy women with more sensitivity than measurements of spinal integral bone by DPA or of appendicular cortical bone by SPA or CCT.

  3. The effect of fat on the measurement of bone mineral density by digital X-ray radiogrammetry (DXR-BMD).

    PubMed

    Colt, Edward; Kälvesten, Johan; Cook, Kenneth; Khramov, Nata; Javed, Fahad

    2010-01-01

    OBJECTIVE: We have previously shown that surrounding fat causes an increase of up to 21% in bone mineral density (BMD) measured by Lunar 'Intelligent DXA' (iDXA), one of the latest generation dual energy X-ray absorptiometry (DXA) scanners [1]. The purpose of our study was to see if it was possible to avoid this artifact when measuring the BMD of metacarpals II, III, and IV by digital X-ray radiogrammetry (DXR). METHODS: We took X-rays of the bones of a cadaveric left hand which were immobilized in a wooden cradle to preserve an approximate in vivo configuration. The X-rays were digitized into Digital Imaging and Communications in Medicine (DICOM) files which were analyzed using dxr-online (dxr-online, Sectra, Sweden) which uses the same DXR-BMD algorithm previously used by Pronosco X-posure v2 and Sectra Osteoporosis package. The X-rays were repeated four times. We then surrounded the bones with a layer of lard, and again X-rayed four times. This process was repeated with the bones were covered by two layers, and then three layers of lard. RESULTS: The measured DXR-BMD increased by a maximum of 0.44% when the metacarpals were covered by either two or three layers of lard compared with when the metacarpals were not covered by lard. CONCLUSION: The measurement of metacarpal BMD measured by DXR is minimally affected by surrounding lard. The measurement of metacarpal BMD by DXR seems to be a way of avoiding the artifactual change in BMD caused by fat, when it is measured by DXA. PMID:21403849

  4. [Methods of imaging and bone densitometry in osteoporosis of patients with inflammatory rheumatoid diseases].

    PubMed

    Lingg, G

    2006-09-01

    Besides clinical history and clinical findings conventional X-ray is important in the evaluation of osteoporosis as the third diagnostic tool. Its purpose is mainly excluding other diseases and proof of fractures as well as their follow up. Also X-ray is able to demonstrate complications of osteoporosis such as insuffiency fractures and effects of therapy as for example fluorosis. For very early diagnosis bone densitometry is used. Today the improved methods deliver fracture prediction percentages of high value. As a planar measurement method DXA of the spine and of the femoral neck can be used. Volumetric tools, which can measure trabecular bone, without overlying cortical bone, are computed tomography of the spine and of the distal radius. Quantitative ultrasound is an interesting approach, but which does not really measure bone densitometry and which is net yet suited for clinical follow up. Quantitative Magnetic Resonance is far from routine clinical application. PMID:16947037

  5. Nuclear magnetic resonance for measurement of body composition in infants and children

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Measurement of body composition in infants and children is currently challenging. Air Displacement Plethysmography (ADP) has not been validated between ages 6 mo and 6 y and the requirement for stillness of the Dual-energy X-ray Absorptiometry (DXA) technique limits its use. Quantitative Nuclear Ma...

  6. Interaction of clothing and body mass index affects validity of air displacement plethysmography in adults

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Objective: Examine the effect of alternate clothing schemes on validity of Bod Pod to estimate percent body fat (BF) compared to dual x-ray absorptiometry (DXA), and determine if these effects differ by body mass index (BMI). Design: Cross-sectional Subjects: 132 healthy adults aged 19-81 classifi...

  7. Fat and Lean Masses in Youths with Down Syndrome: Gender Differences

    ERIC Educational Resources Information Center

    Gonzalez-Aguero, Alejandro; Ara, Ignacio; Moreno, Luis A.; Vicente-Rodriguez, German; Casajus, Jose A.

    2011-01-01

    The present study aimed at comparing fat and lean masses between children and adolescents with and without Down syndrome (DS) and evaluating the presence of sexual dimorphism. Total and regional fat and lean masses were assessed by dual energy X-ray absorptiometry (DXA) and the percentage of body fat (%BF) by air-displacement plethysmography (ADP)…

  8. Effects of Whole Body Vibration Training on Body Composition in Adolescents with Down Syndrome

    ERIC Educational Resources Information Center

    Gonzalez-Aguero, Alejandro; Matute-Llorente, Angel; Gomez-Cabello, Alba; Casajus, Jose A.; Vicente-Rodriguez, German

    2013-01-01

    The present study aimed to determine the effect of 20 weeks of whole body vibration (WBV) on the body composition of adolescents with Down syndrome (DS). Thirty adolescent with DS were divided into two groups: control and WBV. Whole body, upper and lower limbs body fat and lean body mass were measured with dual energy X-ray absorptiometry (DXA)…

  9. TIBIAL PLATEAU PROXIMAL AND DISTAL BONE BEHAVE SIMILARLY: BOTH ARE ASSOCIATED WITH FEATURES OF KNEE OSTEOARTHRITIS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is a growing imperative to understand how changes in peri-articular bone relate to pathological progression of knee osteoarthritis (KOA). Peri-articular bone density can be measured using dual x-ray absorptiometry (DXA). The medial:lateral tibial BMD ratio (M:L BMD) is associated with MRI and...

  10. Baseline Vitamin D Status is Predictive of Longitudinal Change in Tibial BMD in Knee Osteoarthritis (OA)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With its lack of effective treatment and high prevalence, the public health impact of OA is substantial. Peri-articular bone in OA can be evaluated with the medial:lateral tibial BMD ratio (M:L BMD) obtained from dual x-ray absorptiometry (DXA). Higher M:L BMD is associated with medial OA features...

  11. Body mass index bias in defining obesity of diverse young adults: The Training Intervention and Genetics of Exercise Response (TIGER) Study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The BMI cut-score used to define overweight and obesity was derived primarily using data from Caucasian men and women. The present study evaluated the racial/ethnic bias of BMI to estimate the adiposity of young men and women (aged 17–35 years) using dual-energy X-ray absorptiometry (DXA) determinat...

  12. Effect or ractopamine on growth and body composition of pigs during compensatory growth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The purpose of this study was to measure the growth and body composition of pigs during normal or compensatory growth from 60 to 100 kg, without (cont) or with ractopamine (rac) supplementation (20 mg/kg of diet). Thirty-four pigs were scanned by dual X-ray absorptiometry (DXA) for body composition...

  13. Bone mineral density test

    MedlinePlus

    BMD test; Bone density test; Bone densitometry; DEXA scan; DXA; Dual-energy x-ray absorptiometry; p-DEXA; Osteoporosis-BMD ... Bone density testing can be done several ways. The most common and accurate way uses a dual-energy x- ...

  14. Factors that influence bone mass of healthy children and adolescents measured by quantitative ultrasound at the hand phalanges: a systematic review☆

    PubMed Central

    Krahenbühl, Tathyane; Gonçalves, Ezequiel Moreira; Costa, Eduardo Tavares; Barros, Antonio de Azevedo

    2014-01-01

    Objective: To analyze the main factors that influence bone mass in children and teenagers assessed by quantitative ultrasound (QUS) of the phalanges. Data source: A systematic literature review was performed according to the PRISMA method with searches in databases Pubmed/Medline, SciELO and Bireme for the period 2001-2012, in English and Portuguese languages, using the keywords: children, teenagers, adolescent, ultrasound finger phalanges, quantitative ultrasound of phalanges, phalangeal quantitative ultrasound. Data synthesis: 21 articles were included. Girls had, in QUS, Amplitude Dependent Speed of Sound (AD-SoS) values higher than boys during pubertal development. The values of the parameters of QUS of the phalanges and dual-energy X-ray Absorptiometry (DXA) increased with the increase of the maturational stage. Anthropometric variables such as age, weight, height, body mass index (BMI), lean mass showed positive correlations with the values of QUS of the phalanges. Physical activity has also been shown to be positively associated with increased bone mass. Factors such as ethnicity, genetics, caloric intake and socioeconomic profile have not yet shown a conclusive relationship and need a larger number of studies. Conclusions: QUS of the phalanges is a method used to evaluate the progressive acquisition of bone mass during growth and maturation of individuals in school phase, by monitoring changes that occur with increasing age and pubertal stage. There were mainly positive influences variables of sex, maturity, height, weight and BMI, with similar data when compared to the gold standard method, the DXA. PMID:25479860

  15. Screening and early diagnosis of osteoporosis through X-ray and ultrasound based techniques

    PubMed Central

    Pisani, Paola; Renna, Maria Daniela; Conversano, Francesco; Casciaro, Ernesto; Muratore, Maurizio; Quarta, Eugenio; Paola, Marco Di; Casciaro, Sergio

    2013-01-01

    Effective prevention and management of osteoporosis would require suitable methods for population screenings and early diagnosis. Current clinically-available diagnostic methods are mainly based on the use of either X-rays or ultrasound (US). All X-ray based methods provide a measure of bone mineral density (BMD), but it has been demonstrated that other structural aspects of the bone are important in determining fracture risk, such as mechanical features and elastic properties, which cannot be assessed using densitometric techniques. Among the most commonly used techniques, dual X-ray absorptiometry (DXA) is considered the current “gold standard” for osteoporosis diagnosis and fracture risk prediction. Unfortunately, as other X-ray based techniques, DXA has specific limitations (e.g., use of ionizing radiation, large size of the equipment, high costs, limited availability) that hinder its application for population screenings and primary care diagnosis. This has resulted in an increasing interest in developing reliable pre-screening tools for osteoporosis such as quantitative ultrasound (QUS) scanners, which do not involve ionizing radiation exposure and represent a cheaper solution exploiting portable and widely available devices. Furthermore, the usefulness of QUS techniques in fracture risk prediction has been proven and, with the last developments, they are also becoming a more and more reliable approach for assessing bone quality. However, the US assessment of osteoporosis is currently used only as a pre-screening tool, requiring a subsequent diagnosis confirmation by means of a DXA evaluation. Here we illustrate the state of art in the early diagnosis of this “silent disease” and show up recent advances for its prevention and improved management through early diagnosis. PMID:24349644

  16. Optimizing Bone Health in Duchenne Muscular Dystrophy

    PubMed Central

    Buckner, Jason L.; Bowden, Sasigarn A.; Mahan, John D.

    2015-01-01

    Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder characterized by progressive muscle weakness, with eventual loss of ambulation and premature death. The approved therapy with corticosteroids improves muscle strength, prolongs ambulation, and maintains pulmonary function. However, the osteoporotic impact of chronic corticosteroid use further impairs the underlying reduced bone mass seen in DMD, leading to increased fragility fractures of long bones and vertebrae. These serious sequelae adversely affect quality of life and can impact survival. The current clinical issues relating to bone health and bone health screening methods in DMD are presented in this review. Diagnostic studies, including biochemical markers of bone turnover and bone mineral density by dual energy X-ray absorptiometry (DXA), as well as spinal imaging using densitometric lateral spinal imaging, and treatment to optimize bone health in patients with DMD are discussed. Treatment with bisphosphonates offers a method to increase bone mass in these children; oral and intravenous bisphosphonates have been used successfully although treatment is typically reserved for children with fractures and/or bone pain with low bone mass by DXA. PMID:26124831

  17. A New Equation to Estimate Muscle Mass from Creatinine and Cystatin C

    PubMed Central

    Kim, Cheol-Ho; Kim, Kwang-il; Chin, Ho Jun; Lee, Hajeong

    2016-01-01

    Background With evaluation for physical performance, measuring muscle mass is an important step in detecting sarcopenia. However, there are no methods to estimate muscle mass from blood sampling. Methods To develop a new equation to estimate total-body muscle mass with serum creatinine and cystatin C level, we designed a cross-sectional study with separate derivation and validation cohorts. Total body muscle mass and fat mass were measured using dual-energy x-ray absorptiometry (DXA) in 214 adults aged 25 to 84 years who underwent physical checkups from 2010 to 2013 in a single tertiary hospital. Serum creatinine and cystatin C levels were also examined. Results Serum creatinine was correlated with muscle mass (P < .001), and serum cystatin C was correlated with body fat mass (P < .001) after adjusting glomerular filtration rate (GFR). After eliminating GFR, an equation to estimate total-body muscle mass was generated and coefficients were calculated in the derivation cohort. There was an agreement between muscle mass calculated by the novel equation and measured by DXA in both the derivation and validation cohort (P < .001, adjusted R2 = 0.829, β = 0.95, P < .001, adjusted R2 = 0.856, β = 1.03, respectively). Conclusion The new equation based on serum creatinine and cystatin C levels can be used to estimate total-body muscle mass. PMID:26849842

  18. Can ultrasound be used to estimate bone mineral density in children with growth problems?

    PubMed Central

    Khan, Khalid M; Sarafoglou, Kyriakie; Somani, Arif; Frohnert, Brigitte; Miller, Bradley S.

    2016-01-01

    Aim To assess predictability of bone mineral density (BMD) of the lumbar spine (LS) determined by duel energy x-ray absorptiometry (DXA) using by ultrasound- speed of sound of the right and left radii (SOS-R and SOS-L) in patients with growth problems. Methods Ultrasound and DXA were compared in patients with advanced, normal and delayed bone ages assessed by Greulich and Pyle (GP) and Tanner and Whitehouse (TW3) methods. Results There was a strong correlation (r), of raw scores, between SOS-R and SOS-L, r=0.81, P=0.000, and their respective Z-scores, r=0.78, P=0.000. Z-score correlations were poor between SOS-R or SOS-L and LS-BMD. Sensitivity, specificity, positive- and negative predictive value of SOS-R, Z-scores for predicting normal (>−1 to < 1) and low (< −1) LS-BMD, Z scores were poor. For high (> 1) LS-BMD, Z scores were 22%, 93%, 29%, and 90% respectively for SOS-R and for SOS-L, 25%, 89%, 20%, and 91%. For very low (< −2) LS-BMD, SOS-R and SOS-L were the same, respectively 29%, 91%, 40%, and 86%. Conclusion Ultrasound of the radius is a poor predictor of radiologically assessed BMD at the lumbar spine, especially with delayed bone age. PMID:23750846

  19. Survey of risk factors for osteoporosis and osteoprotective behaviors among patients with epilepsy.

    PubMed

    Fedorenko, Marianna; Wagner, Mary L; Wu, Brenda Y

    2015-04-01

    The prevalence of risk factors for osteoporosis in persons with epilepsy, patients' awareness of their risk, and their engagement in osteoprotective behaviors were assessed in this study. Two hundred and sixty patients with epilepsy (F=51.5%, average age=42) completed a survey tool. Of 106 patients with a dual energy X-ray absorptiometry (DXA) result, 52% had low bone mineral density, and 11% had osteoporosis. The results suggest that the majority of patients with epilepsy do not engage in bone-protective behaviors. Those who have undergone a DXA scan may be more likely to take calcium and vitamin D supplementation compared with those who did not undergo a DXA scan, but they do not engage in other osteoprotective behaviors. Many patients did not accurately report their DXA results, indicating that better patient education is warranted. PMID:25812937

  20. Use of fast neutrons for assessing sarcopenia by measuring body phosphorus: relevance to health and quality of life of the elderly

    NASA Astrophysics Data System (ADS)

    Kehayias, Joseph J.; Zhuang, Hong; Doherty, Patricia L.

    1997-02-01

    Sarcopenia, defined as the loss of skeletal muscle with age, may lead to frailty, fractures due to falls, and reduced immunity to disease. By understanding the causes of muscle loss with age we will be able to develop ways of maintaining functional capacity and quality of life for the elderly. Elemental Partition Analysis (EPA) is a new approach to body composition assessment. A major element of the body is measured and then, by means of other measurements, is partitioned to the contributing body compartments. We developed a model for measuring total body muscle by applying the EPA method to total body phosphorus (TBP). We measure TBP by in vivo fast neutron activation analysis using the reaction 31P(n,(alpha) )28Al. The main contributors to TBP are bone and skeletal muscle. Adipose tissue and the liver contribute less than 3 percent. We use dual-energy x-ray absorptiometry (DXA) to evaluate the contribution of bone to TBP. COrrections are applied for the small contributions of the liver and adipose tissue to TBP to derive muscle phosphorus. The technique requires high precision measurements for both TBP and DXA. The total body radiation exposure for measuring human subjects is 0.30 mSv.

  1. Smart Multi-Frequency Bioelectrical Impedance Spectrometer for BIA and BIVA Applications.

    PubMed

    Harder, Rene; Diedrich, Andre; Whitfield, Jonathan S; Buchowski, Macie S; Pietsch, John B; Baudenbacher, Franz J

    2016-08-01

    Bioelectrical impedance analysis (BIA) is a noninvasive and commonly used method for the assessment of body composition including body water. We designed a small, portable and wireless multi-frequency impedance spectrometer based on the 12 bit impedance network analyzer AD5933 and a precision wide-band constant current source for tetrapolar whole body impedance measurements. The impedance spectrometer communicates via Bluetooth with mobile devices (smart phone or tablet computer) that provide user interface for patient management and data visualization. The export of patient measurement results into a clinical research database facilitates the aggregation of bioelectrical impedance analysis and biolectrical impedance vector analysis (BIVA) data across multiple subjects and/or studies. The performance of the spectrometer was evaluated using a passive tissue equivalent circuit model as well as a comparison of body composition changes assessed with bioelectrical impedance and dual-energy X-ray absorptiometry (DXA) in healthy volunteers. Our results show an absolute error of 1% for resistance and 5% for reactance measurements in the frequency range of 3 kHz to 150 kHz. A linear regression of BIA and DXA fat mass estimations showed a strong correlation (r(2)=0.985) between measures with a maximum absolute error of 6.5%. The simplicity of BIA measurements, a cost effective design and the simple visual representation of impedance data enables patients to compare and determine body composition during the time course of a specific treatment plan in a clinical or home environment. PMID:26863670

  2. Visceral Fat Mass Has Stronger Associations with Diabetes and Prediabetes than Other Anthropometric Obesity Indicators among Korean Adults

    PubMed Central

    Jung, Suk Hwa; Ha, Kyoung Hwa

    2016-01-01

    Purpose This study determined which obesity measurement correlates the best with diabetes and prediabetes. Materials and Methods This cross-sectional study enrolled 1603 subjects (611 men, 992 women; age 30–64 years) at the Cardiovascular and Metabolic Diseases Etiology Research Center. Body mass index, waist circumference, waist-height ratio, waist-hip ratio, waist-thigh ratio, and visceral fat were used as measures of obesity. Visceral fat was acquired using dual-energy X-ray absorptiometry (DXA). The prevalences of diabetes and prediabetes were defined using the criteria in the American Diabetes Association 2015 guidelines. Results After adjusting for age and other potential confounding factors, participants with a visceral fat mass in the upper 10th percentile had a higher odds ratio (OR) for diabetes and prediabetes than the upper 10th percentile of other adiposity indices [men, OR=15.9, 95% confidence interval (CI)=6.4–39.2; women, OR=6.9, 95% CI=3.5–13.7]. Visceral fat mass also had the highest area under the curve with diabetes and prediabetes in both men (0.69, 95% CI=0.64–0.73) and women (0.70, 95% CI=0.67–0.74) compared to other anthropometric measurements of obesity. Conclusion Visceral fat mass measured using DXA is an indicator of diabetes or prediabetes, due to its ability to differentiate between abdominal visceral and subcutaneous fat. PMID:26996568

  3. Impact of creatine supplementation in combination with resistance training on lean mass in the elderly

    PubMed Central

    Pinto, Camila Lemos; Botelho, Patrícia Borges; Carneiro, Juliana Alves

    2016-01-01

    Abstract Background Human ageing is a process characterized by loss of muscle mass, strength, and bone mass. We aimed to examine the efficacy of low‐dose creatine supplementation associated with resistance training on lean mass, strength, and bone mass in the elderly. Methods This was a 12‐week, parallel‐group, double‐blind, randomized, placebo‐controlled trial. The individuals were randomly allocated into one of the following groups: placebo plus resistance training (PL + RT) and creatine supplementation plus resistance training (CR + RT) . The participants were assessed at baseline and after 12 weeks. The primary outcomes were lean mass and strength, assessed by dual energy X‐ray absorptiometry (DXA) and ten‐repetition maximal tests (10 RM), respectively. Secondary outcomes included the lumbar spine, right and left femoral neck, both femur and whole body bone mineral density (BMD), and whole body bone mineral content (BMC), assessed by DXA. Results The CR + RT group had superior gains in lean mass when compared with the PL + RT group (P = 0.02). Changes in the 10 RM tests in bench press and leg press exercises, body composition, BMD, and BMC of all assessed sites did not significantly differ between the groups (P > 0.05). Conclusions Twelve weeks of low‐dose creatine supplementation associated with resistance training resulted in increases in lean mass in the elderly. PMID:27239423

  4. Fat distribution in children and adolescents with myelomeningocele

    PubMed Central

    Mueske, Nicole M; Ryan, Deirdre D; Van Speybroeck, Alexander L; Chan, Linda S; Al Wren, Tishya

    2014-01-01

    AIM To evaluate quantitatively fat distribution in children and adolescents with myelomeningocele using dual-energy X-ray absorptiometry (DXA). METHOD Cross-sectional DXA measurements of the percentage of fat in the trunk, arms, legs, and whole body were compared between 82 children with myelomeningocele (45 males, 37 females; mean age 9y 8mo, SD 2y 7mo; 22 sacral, 13 low lumbar, 47 mid lumbar and above) and 119 comparison children (65 males, 54 females; mean age 10y 4mo, SD 2y 4mo). Differences in fat distribution between groups were evaluated using univariate and multivariate analyses. RESULTS Children with myelomeningocele had higher total body fat (34% vs 31%, p=0.02) and leg fat (42% vs 35%, p<0.001than comparison children, but no differences in trunk or arm fat after adjustment for anthropometric measures. INTERPRETATION Children with myelomeningocele have higher than normal total body and leg fat, but only children with higher level lesions have increased trunk fat, which may be caused by greater obesity in this group. Quantifying segmental fat distribution may aid in better assessment of excess weight and, potentially, the associated health risks. PMID:25251828

  5. Concordance between measured and estimated appendicular muscle mass in adult females.

    PubMed

    Lekamwasam, S; Nanayakkara, J

    2015-09-01

    This study assessed the accuracy of a selected formula used to estimate the appendicular muscle mass (AMM) which is linked with many clinical outcomes. A group of community-dwelling adult women (n=80) had their AMM measured using dual energy x-ray absorptiometry (DXA). The same was estimated using a formula already published {Skeletal muscle mass = (0.244 × BW in kg) + (7.80 × Ht in meters) + (6.6 × Sex) - (0.098 × Age) + race - 3.3} (sex=0 for female and 1 for male, race =-1.2 for Asian, 1.4 for African American and 0 for White and Hispanic).The two datasets were compared for accuracy and precision. Mean AMM measured by DXA and estimated by the formula were very close (14.8 and 14.5 kg) and the difference ranged from -1.2 to 3.6 kg. Correlation between the two datasets was high (r=0.92) and the Bland-Altman plot showed an acceptable measurement agreement between the two methods. Results were independent of age and BMI. The formula used in this analysis gave an accurate estimation of the absolute AMM in women included in this study. PMID:26520864

  6. Total body skeletal muscle mass: estimation by creatine (methyl-d3) dilution in humans

    PubMed Central

    Walker, Ann C.; O'Connor-Semmes, Robin L.; Leonard, Michael S.; Miller, Ram R.; Stimpson, Stephen A.; Turner, Scott M.; Ravussin, Eric; Cefalu, William T.; Hellerstein, Marc K.; Evans, William J.

    2014-01-01

    Current methods for clinical estimation of total body skeletal muscle mass have significant limitations. We tested the hypothesis that creatine (methyl-d3) dilution (D3-creatine) measured by enrichment of urine D3-creatinine reveals total body creatine pool size, providing an accurate estimate of total body skeletal muscle mass. Healthy subjects with different muscle masses [n = 35: 20 men (19–30 yr, 70–84 yr), 15 postmenopausal women (51–62 yr, 70–84 yr)] were housed for 5 days. Optimal tracer dose was explored with single oral doses of 30, 60, or 100 mg D3-creatine given on day 1. Serial plasma samples were collected for D3-creatine pharmacokinetics. All urine was collected through day 5. Creatine and creatinine (deuterated and unlabeled) were measured by liquid chromatography mass spectrometry. Total body creatine pool size and muscle mass were calculated from D3-creatinine enrichment in urine. Muscle mass was also measured by magnetic resonance imaging (MRI), dual-energy x-ray absorptiometry (DXA), and traditional 24-h urine creatinine. D3-creatine was rapidly absorbed and cleared with variable urinary excretion. Isotopic steady-state of D3-creatinine enrichment in the urine was achieved by 30.7 ± 11.2 h. Mean steady-state enrichment in urine provided muscle mass estimates that correlated well with MRI estimates for all subjects (r = 0.868, P < 0.0001), with less bias compared with lean body mass assessment by DXA, which overestimated muscle mass compared with MRI. The dilution of an oral D3-creatine dose determined by urine D3-creatinine enrichment provides an estimate of total body muscle mass strongly correlated with estimates from serial MRI with less bias than total lean body mass assessment by DXA. PMID:24764133

  7. Quantitative ultrasound does not identify patients with an inflammatory disease at risk of vertebral deformities

    PubMed Central

    Heijckmann, A Caroline; Dumitrescu, Bianca; Nieuwenhuijzen Kruseman, Arie C; Geusens, Piet; Wolffenbuttel, Bruce HR; De Vries, Jolanda; Drent, Marjolein; Huijberts, Maya SP

    2008-01-01

    Background Previous studies from our group have shown that a high prevalence of vertebral deformities suggestive of fracture can be found in patients with an inflammatory disease, despite a near normal bone mineral density (BMD). As quantitative ultrasound (QUS) of the heel can be used for refined assessment of bone strength, we evaluated whether QUS can be used to identify subjects with an inflammatory disease with an increased chance of having a vertebral fracture. Methods 246 patients (mean age: 44 ± 12.4 years) with an inflammatory disease (sarcoidosis or inflammatory bowel disease (IBD)) were studied. QUS of the heel and BMD of the hip (by dual X-ray absorptiometry (DXA)) were measured. Furthermore lateral single energy densitometry of the spine for assessment of vertebral deformities was done. Logistic regression analysis was performed to assess the strength of association between the prevalence of a vertebral deformity and BMD and QUS parameters, adjusted for gender and age. Results Vertebral deformities (ratio of <0.80) were found in 72 vertebrae of 54 subjects (22%). In contrast to the QUS parameters BUA (broadband ultrasound attenuation) and SOS (speed of sound), T-score of QUS and T-scores of the femoral neck and trochanter (DXA) were lower in the group of patients with vertebral deformities. Logistic regression analysis showed that the vertebral deformity risk increases by about 60 to 90% per 1 SD reduction of BMD (T-score) determined with DXA but not with QUS. Conclusion Our findings imply that QUS measurements of the calcaneus in patients with an inflammatory condition, such as sarcoidosis and IBD, are likely of limited value to identify patients with a vertebral fracture. PMID:18492278

  8. Expanding the Description of Spaceflight Effects beyond Bone Mineral Density [BMD]: Trabecular Bone Score [TBS] in ISS Astronauts

    NASA Technical Reports Server (NTRS)

    Sibonga, J. D.; Spector, E. R.; King, L. J.; Evans, H. J.; Smith, S. A.

    2014-01-01

    Dual-energy x-ray absorptiometry [DXA] is the widely-applied bone densitometry method used to diagnose osteoporosis in a terrestrial population known to be at risk for age-related bone loss. This medical test, which measures areal bone mineral density [aBMD] of clinically-relevant skeletal sites (e.g., hip and spine), helps the clinician to identify which persons, among postmenopausal women and men older than 50 years, are at high risk for low trauma or fragility fractures and might require an intervention. The most recognized osteoporotic fragility fracture is the vertebral compression fracture which can lead to kyphosis or hunched backs typically seen in the elderly. DXA measurement of BMD however is recognized to be insufficient as a sole index for assessing fracture risk. DXA's limitation may be related to its inability to monitor changes in structural parameters, such as trabecular vs. cortical bone volumes, bone geometry or trabecular microarchitecture. Hence, in order to understand risks to human health and performance due to space exposure, NASA needs to expand its measurements of bone to include other contributors to skeletal integrity. To this aim, the Bone and Mineral Lab conducted a pilot study for a novel measurement of bone microarchitecture that can be obtained by retrospective analysis of DXA scans. Trabecular Bone Score (TBS) assesses changes to trabecular microarchitecture by measuring the grey color "texture" information extracted from DXA images of the lumbar spine. An analysis of TBS in 51 ISS astronauts was conducted to assess if TBS could detect 1) an effect of spaceflight and 2) a response to countermeasures independent of DXA BMD. In addition, changes in trunk body lean tissue mass and in trunk body fat tissue mass were also evaluated to explore an association between body composition, as impacted by ARED exercise, and bone microarchitecture. The pilot analysis of 51 astronaut scans of the lumbar spine suggests that, following an ISS

  9. Effect of Self-Referral on Bone Mineral Density Testing and Osteoporosis Treatment

    PubMed Central

    Warriner, Amy H.; Outman, Ryan C.; Feldstein, Adrianne C.; Roblin, Douglas W.; Allison, Jeroan J.; Curtis, Jeffrey R.; Redden, David T.; Rix, Mary M.; Robinson, Brandi E.; Rosales, A. Gabriela; Safford, Monika M.; Saag, Kenneth G.

    2014-01-01

    Background Despite national guidelines recommending bone mineral density screening with dual-energy xray absorptiometry (DXA) in women ≥65 years old, many women do not receive initial screening. Objective To determine the effectiveness of health system and patient-level interventions designed to increase appropriate DXA testing and osteoporosis treatment through (1) an invitation to self-refer for DXA (self-referral), (2) self-referral plus patient educational materials, and (3) usual care (UC, physician referral). Research Design Parallel, group-randomized, controlled trials performed at Kaiser Permanente Northwest (KPNW) and Kaiser Permanente Georgia (KPG). Subjects Women ≥ 65 years old without a DXA in past 5 years. Measures DXA completion rates 90 days after intervention mailing and osteoporosis medication receipt 180 days after initial intervention mailing. Results From >12,000 eligible women, those randomized to self-referral were significantly more likely to receive a DXA than UC (13.0 – 24.1% self-referral vs. 4.9 – 5.9% UC, p < 0.05). DXA rates did not significantly increase with patient educational materials. Osteoporosis was detected in a greater proportion of self-referral women compared to UC (p < 0.001). The number needed to receive an invitation to result in a DXA in KPNW and KPG regions was approximately 5 and 12, respectively. New osteoporosis prescription rates were low (0.8 – 3.4%) but significantly greater among self-referral versus UC in KPNW. Conclusions DXA rates significantly improved with a mailed invitation to schedule a scan without physician referral. Providing women the opportunity to self-refer may be an effective, low-cost strategy to increase access for recommended osteoporosis screening. PMID:24984211

  10. BFH-OST, a new predictive screening tool for identifying osteoporosis in postmenopausal Han Chinese women

    PubMed Central

    Ma, Zhao; Yang, Yong; Lin, JiSheng; Zhang, XiaoDong; Meng, Qian; Wang, BingQiang; Fei, Qi

    2016-01-01

    Purpose To develop a simple new clinical screening tool to identify primary osteoporosis by dual-energy X-ray absorptiometry (DXA) in postmenopausal women and to compare its validity with the Osteoporosis Self-Assessment Tool for Asians (OSTA) in a Han Chinese population. Methods A cross-sectional study was conducted, enrolling 1,721 community-dwelling postmenopausal Han Chinese women. All the subjects completed a structured questionnaire and had their bone mineral density measured using DXA. Using logistic regression analysis, we assessed the ability of numerous potential risk factors examined in the questionnaire to identify women with osteoporosis. Based on this analysis, we build a new predictive model, the Beijing Friendship Hospital Osteoporosis Self-Assessment Tool (BFH-OST). Receiver operating characteristic curves were generated to compare the validity of the new model and OSTA in identifying postmenopausal women at increased risk of primary osteoporosis as defined according to the World Health Organization criteria. Results At screening, it was found that of the 1,721 subjects with DXA, 22.66% had osteoporosis and a further 47.36% had osteopenia. Of the items screened in the questionnaire, it was found that age, weight, height, body mass index, personal history of fracture after the age of 45 years, history of fragility fracture in either parent, current smoking, and consumption of three of more alcoholic drinks per day were all predictive of osteoporosis. However, age at menarche and menopause, years since menopause, and number of pregnancies and live births were irrelevant in this study. The logistic regression analysis and item reduction yielded a final tool (BFH-OST) based on age, body weight, height, and history of fracture after the age of 45 years. The BFH-OST index (cutoff =9.1), which performed better than OSTA, had a sensitivity of 73.6% and a specificity of 72.7% for identifying osteoporosis, with an area under the receiver operating

  11. Bone loss: Quantitative imaging techniques for assessing bone mass in rheumatoid arthritis

    PubMed Central

    Njeh, Christopher F; Genant, Harry K

    2000-01-01

    Osteoporosis is associated with low bone mass and microarchitectural deterioration of bone tissue with clinical manifestation of low trauma fractures. Rheumatoid arthritis (RA) is a risk factor due to generalized and articular bone loss. This minireview presents past and current bone mass measurement techniques in RA. These techniques include: plain radiographs, absorptiometry, quantitative computed tomography (QCT) and ultrasound. The most widely used technique is dual x-ray absorptiometry (DXA). RA patients have lower bone mass as compared with normals and substantial bone loss may occur early after the onset of disease. Measurement of bone mineral density (BMD) at the hand using either DXA or ultrasound maybe a useful tool in the management of RA patients. PMID:11094457

  12. [Dual x-ray absorptiometry in the diagnosis of osteoporosis].

    PubMed

    Vojtassák, J

    1993-01-01

    The author presents a review providing information on contemporary modern radiological possibilities as regards the diagnosis of osteoporosis at the First Orthopaedic Clinic in Bratislava. At present this department possesses a densitometer LUNAR DPX-L. This apparatus assesses the bone density on the basis of double X-ray absorption. The software available at present makes it possible to assess the bone density of the lumbar spine in the anterio-posterior and lateral projection, as well as the proximal femur and whole body. The mean time required for assessment is 4 mins. 24 secs. to 16 mins. 30 secs. The mean radiation load of the patient is 1.5 mrem, the maximal load 3.5 mrem. The apparatus compares the assessed density values with mean values of the healthy population, it evaluates automatically statistical values of the Z and T score. These results are presented either as a coloured graph or as values of bone mineral density and bone mineral content. The author explains in more detail the principle of modern densitometry and its development during the past three decades. PMID:8346691

  13. Dual photon absorptiometry: Validation of mineral and fat measurements

    SciTech Connect

    Heymsfield, S.B.; Wang, J.; Sulet, M.; Lichtman, S.; Pierson, R.N. Jr. ); Kehayias, J. . USDA Human Nutrition Research Center on Aging at Tufts Univ.); Kamen, Y.; Dilmanian, F.A. ); Lindsay, R. . Coll. of Physicians and Surgeons)

    1989-01-01

    Photons passing through human tissue undergo attenuation in relation to the specific chemical substances with which they interact. By selecting two appropriate photon energies and recording their attenuation, the investigator can solve simultaneous equations that subdivide body mass into two components: soft tissue and bone mineral ash. The aim of this paper is to describe and to validate the estimates of body composition derived by dual photon systems. The initial studies largely involved dual photon absorptiometers, although the discussion will also include the more recently developed dual energy x-ray absorptiometers. 13 refs., 7 figs., 4 tabs.

  14. [Methods of nutritional assessment in chronic obstructive lung diseases].

    PubMed

    Doré, M F; Laaban, J P

    1999-06-01

    A poor nutritional state is often encountered in the course of chronic obstructive lung disease (COLD) and worsens the prognosis. The methods used to assess nutritional status proposed in the literature vary greatly. We detail here the methods used in clinical practice and in research, describing results obtained in patients with COLD. Appropriate routine tests are discussed. Body weight should be followed in this population, but weight loss may be masked by sodium-water retention. Bioelectric impedancemetry or biphotonic absorptiometry are used to define body composition in patients with COLD. Lean mass can be measured with the creatinine/height index but is difficult in the ambulatory patient. Plasma levels of visceral proteins are often normal and do not appear to be useful markers in these patients. Immunology tests (delayed hypersensitivity, total lymphocyte counts) are not sensitive screening tests. An evaluation of skeletal muscle function using the walking test or an exercise test is recommended before starting a renutrition program and to evaluate its efficacy. PMID:10486837

  15. Bone Density in Peripubertal Boys with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Neumeyer, Ann M.; Gates, Amy; Ferrone, Christine; Lee, Hang; Misra, Madhusmita

    2013-01-01

    We determined whether bone mineral density (BMD) is lower in boys with autism spectrum disorders (ASD) than controls, and also assessed variables that may affect BMD in ASD. BMD was measured using dual energy X-ray absorptiometry (DXA) in 18 boys with ASD and 19 controls 8-14 years old. Boys with ASD had lower BMD Z-scores at the spine, hip and…

  16. [Is it possible to-predict fracture in CKD patients?].

    PubMed

    Tsukamoto, Yusuke

    2016-09-01

    Routine examination of bone mineral density(BMD)by DXA(dual energy X-ray absorptiometry)is useful to predict bone fracture in both CKD nondialysis and dialysis patients. The cutoff value of BMD to predict bone fracture is different between genders and its predictive power is better in patients with lower serum PTH levels than higher counterpart. Increase in serum bone specific alkaline phosphatase is a better predictor of the bone fracture than serum PTH levels. PMID:27561344

  17. Improving Rural Bone Health and Minimizing Fracture Risk in West Virginia: Validation of the World Health Organization FRAX Assessment Tool as a Phone Survey for Osteoporosis Detection.

    PubMed

    Shuler, Franklin D; Scott, Kelly; Wilson-Byrne, Timothy; Morgan, Linda; Olajide, Omolola B

    2016-01-01

    West Virginia ranks second nationally in population ≥ 65 years old placing our state at greater risk for osteoporosis and fracture. The gold standard for detecting osteoporosis is dual X-ray absorptiometry (DXA), yet over half of West Virginia's counties do not have this machine. Due to access barriers, a validated phone-administered fracture prediction tool would be beneficial for osteoporosis screening. The World Health Organization's FRAX fracture prediction tool was administered as a phone survey to 45 patients; these results were compared to DXA bone mineral density determination. Results confirmed that the FRAX phone survey is as reliable as DXA in detecting osteoporosis or clinically significant osteopenia: 92% positive predictive value, 100% negative predictive value, 100% sensitivity and 91% specificity when compared to the gold standard. These promising results allow for the development of telephone-based protocols to improve osteoporosis detection, referral and treatment especially in areas with health care access barriers. PMID:27301160

  18. Prediction of body fat percentage from skinfold and bio-impedance measurements in Indian school children

    PubMed Central

    Kehoe, Sarah H.; Krishnaveni, Ghattu V.; Lubree, Himangi G.; Wills, Andrew K.; Guntupalli, Aravinda M.; Veena, Sargoor R.; Bhat, Dattatray S.; Kishore, Ravi; Fall, Caroline H.D.; Yajnik, Chittaranjan S.; Kurpad, Anura

    2011-01-01

    Background Few equations for calculating body fat percentage (BF%) from field methods have been developed in South Asian children. Objective To assess agreement between BF% derived from primary reference methods and that from skinfold equations and bio-impedance analysis (BIA) in Indian children. Methods We measured BF% in two groups of Indian children. In Pune, 570 rural children aged 6-8 years underwent dual-energy X-ray absorptiometry (DXA) scans. In Mysore 18O was administered to 59 urban children aged 7-9 years. We conducted BIA at 50kHz and anthropometry including subscapular and triceps skinfold thicknesses. We used the published equations of Wickramasinghe, Shaikh, Slaughter and Dezenburg to calculate BF% from anthropometric data and the manufacturer’s equation for BIA measurements. We assessed agreement with values derived from DXA and DLW using Bland Altman analysis. Results Children were light and thin compared to international standards. There was poor agreement between the reference BF% values and those from all equations. Assumptions for Bland Altman analysis were not met for Wickramasinghe, Shaikh and Slaughter equations. The Dezenberg equations under-predicted BF% for most children (mean difference in Pune −13.4, LOA −22.7, −4.0 and in Mysore −7.9, LOA −13.7 and −2.2). The mean bias for the BIA equation in Pune was +5.0% and in Mysore +1.95% and the LOA were wide; −5.0, 15.0 and −7.8, 11.7 respectively. Conclusions Currently available skinfold equations do not accurately predict BF% in Indian children. We recommend development of BIA equations in this population using a 4-compartment model. PMID:21731039

  19. Relationship Between Femur Bone Mineral Density, Body Mass Index and Dental Panoramic Mandibular Cortical Width in Diagnosis of Elderly Postmenopausal Women With Osteoporosis

    PubMed Central

    Devi B.K., Yashoda; Rakesh, N.; Reddy, Sujatha S.; Santana, N.; Shetty, Naresh

    2014-01-01

    Objectives: To measure and determine mandibular cortical width (MCW) on the panoramic radiographs, to evaluate the usefulness of the method in identifying postmenopausal women with low femoral bone mineral densities (f- BMD) and to correlate the radiographic findings on panoramic radiographs with the f-BMD assessed by dual X-ray absorptiometry (DXA) to predict the efficacy of the radiographic method in diagnosing osteoporosis. Materials and Methods: One hundred and twenty postmenopausal women (60 normal and 60 osteoporotic) in the age group of 50-75 y with f-BMD assessed by DXA had undergone panoramic radiographic examination. The patients were classified as normal (T-score ≥ -1.0) and osteoporotic (T-score ≤ -2.5). MCW on panoramic radiographs was measured bilaterally at the mental foramen region with a caliper and their mean was used as the exposure measure in the analysis. Results: Student t-test showed that mean f-BMD, BMI and MCW was found be less in osteoporotic patients as compared to normal group with a statistically significant p-value < 0.001. Pearson correlation coefficient test revealed that MCW correlated positively with f-BMD and showed a significant decrease with age of the patient. Conclusion: Postmenopausal women with low f-BMD had thinner mandibular cortex at the mental foramen region when compared to normal subjects and are more susceptible to femoral neck fractures. Mandibular inferior cortical width at the mental foramen region could be used to identify postmenopausal women with low f- BMD. Hence, dental panoramic radiographs serve as a useful screening tool for early diagnosis of osteoporotic fractures. PMID:25302265

  20. Onion peel extract reduces the percentage of body fat in overweight and obese subjects: a 12-week, randomized, double-blind, placebo-controlled study

    PubMed Central

    Lee, Ji-Sook; Cha, Yong-Jun; Lee, Kyung-Hea

    2016-01-01

    BACKGROUND/OBJECTIVES The anti-obesity effect of quercetin-rich onion peel extract (OPE) was suggested in rats, but information from human studies is limited. This study aimed to investigate the effects of OPE on the body composition of overweight and obese subjects. MATERIALS/METHODS In this 12-week, randomized, double-blind, placebo-controlled study, parallel clinical trials were performed in overweight and obese Korean subjects. Randomly assigned subjects were instructed to take daily either the placebo (male, 6 and female, 30) or OPE capsules containing 100 mg of quercetin (male, 5 and female, 31). Body composition was measured by using bioimpedance and dual-energy X-ray absorptiometry (DXA). Resting energy expenditure (REE) and respiratory quotient (RQ) were evaluated by using indirect calorie measurement methods. Fasting blood levels of glucose, insulin, lipids, and leptin were determined. RESULTS Quercetin-rich OPE supplementation significantly reduced the weight and percentage of body fat as measured by DXA (P = 0.02). These effects were not shown in the control group. Levels of blood glucose (P = 0.04) and leptin (P = 0.001 for placebo, P = 0.002 for OPE) decreased in both groups. Significant increases in REE and RQ were observed in both groups (P = 0.003 for placebo, P = 0.006 for OPE) and in the OPE group alone (P = 0.02), respectively. CONCLUSIONS Quercetin-rich OPE supplementation changed the body composition of the overweight and obese subjects. This result suggests a beneficial role of the anti-obesity effect of OPE human subjects. PMID:27087901

  1. REVIEW: A review of in vivo experimental methods to determine the composition of the human body

    NASA Astrophysics Data System (ADS)

    Sutcliffe, J. F.

    1996-05-01

    This review of experimental methods employed in the measurement of the composition of the human body covers the developments that have occurred over the past 30 years. Early methods such as hydrodensitometry and skinfold anthropometry have been superseded by dual-energy x-ray absorptiometry and bioelectrical impedance spectroscopy. The measurement of the whole-body abundance of certain elements by isotopic dilution, neutron activation analysis and x-ray fluorescence can give important information of clinical significance, but neutron activation facilities remain available in only a few centres worldwide. The relatively simple, rapid and risk-free electrical methods such as multifrequency bioelectrical impedance analysis, which can be employed at the bedside, have been found to be more complicated in their interpretation. Electromagnetic methods may only measure the composition of the human body at its surface. X-ray computed tomography and magnetic resonance imaging have not yet been employed much in body composition measurements. Some models for the composition of the human body are reviewed.

  2. Body composition measurements during infancy.

    PubMed

    Koo, W W

    2000-05-01

    Infancy is the period of most rapid postnatal growth and is accompanied by major changes in body composition (BC). There are many challenges to successfully measuring BC of infants in vivo, which include the inherent limitations in the underlying assumptions for each technique. The small body mass and rapid nonuniform changes in body parts, that is, the components of BC during infancy, can strain the technical limits of all methods. Many techniques for in vivo BC measurement used in older people have been applied to infants. However, the vast majority of them either are difficult to adapt for widespread use in infants, or the roles and limitations for using them during infancy are ill-defined because of limited or no critical validation and cross-calibration studies. Based on validation data from animals, well-defined methodological issues in data acquisition and analyses, availability of normative data, and pertinent accuracy and precision of the technique to allow us to determinate clinically relevant changes in BC within a reasonable time interval, three techniques appear to be most suitable for in vivo BC measurement in infants. Anthropometric measurements can be used in field studies or for group comparisons, and total body electrical conductivity (TOBEC) and selected dual-energy X-ray absorptiometry (DXA) measurements can be used to compare BC in individual infants. DXA has the advantages of being able to measure bone mass and the potential to be adaptable to the widely available existing instruments. However, regardless of the techniques used in measuring BC in infants, meticulous attention to details in data acquisition and data analysis, and a knowledge of the limitations of the particular technique are the prerequisites for generating valid data. PMID:10865776

  3. Assessment of bone mineral density in the jaws and its relationship to radiomorphometric indices

    PubMed Central

    Gulsahi, A; Paksoy, CS; Ozden, S; Kucuk, NO; Cebeci, ARI; Genc, Y

    2010-01-01

    Objectives The aim of this study was to evaluate maxillary, mandibular and femoral neck bone mineral density using dual energy X-ray absorptiometry (DXA) and to determine any correlation between the bone mineral density of the jaws and panoramic radiomorphometric indices. Methods 49 edentulous patients (18 males and 31 females) aged between 41 and 78 years (mean age 60.2 ± 11.04) were examined by panoramic radiography. Bone mineral density (BMD) of the jaws and femoral neck was measured with a DXA; bone mineral density was calculated at the anterior, premolar and molar regions of the maxilla and mandible. Results The mean maxillary molar BMD (0.45 g cm−2) was significantly greater than the maxillary anterior and premolar BMD (0.31 g cm−2, P < 0.05). Furthermore, the mean mandibular anterior and premolar BMD (1.39 g cm−2 and 1.28 g cm−2, respectively) was significantly greater than the mean mandibular molar BMD (1.09 g cm−2, P < 0.01). Although BMD in the maxillary anterior and premolar regions were correlated, BMD in all the mandibular regions were highly correlated. Maxillary and mandibular BMD were not correlated with femoral BMD. In addition, mandibular cortical index (MCI) classification, mental index (MI) or panoramic mandibular index (PMI) values were not significantly correlated with the maxillary and mandibular BMDs (P > 0.05). Conclusions The BMD in this study was highest in the mandibular anterior region and lowest in the maxillary anterior and premolar regions. The BMD of the jaws was not correlated with either femoral BMD or panoramic radiomorphometric indices. PMID:20587652

  4. Toward Body Composition Reference Data for Infants, Children, and Adolescents123

    PubMed Central

    Wells, Jonathan C. K.

    2014-01-01

    Growth charts for weight and height have provided the basis for assessment of children’s nutritional status for over half a century, with charts for body mass index (BMI) introduced in the 1990s. However, BMI does not provide information on the proportions of fat and lean mass; and within the past decade, growth charts for children’s body composition have been produced by using techniques such as skinfold thicknesses, body circumferences, bioelectrical impedance analysis (BIA), and dual-energy X-ray absorptiometry (DXA). For public health research, BIA and skinfold thicknesses show negligible average bias but have wider limits of agreement than specialized techniques. For patients, DXA is the best individual method, but multicomponent models remain ideal because they address perturbations in lean mass composition. Data can be expressed in age- and sex-specific SD scores, in some cases adjusting for height. Most such reference data derive from high-income countries, but techniques such as air-displacement plethysmography allow infant body composition growth charts to be developed in low- and middle-income settings, where the data may improve understanding of the effects of low birth weight, wasting, and stunting on body composition. Recent studies suggest that between-population variability in body composition may derive in part from genetic factors, suggesting a universal human body composition reference may not be viable. Body composition growth charts may be extended into adult life to evaluate changes in fat and lean mass through the entire life course. These reference data will improve the understanding of the association between growth, body composition, health, and disease. PMID:24829484

  5. Trabecular homogeneity index derived from plain radiograph to evaluate bone quality.

    PubMed

    Thevenot, Jérôme; Hirvasniemi, Jukka; Finnilä, Mikko; Pulkkinen, Pasi; Kuhn, Volker; Link, Thomas; Eckstein, Felix; Jämsä, Timo; Saarakkala, Simo

    2013-12-01

    Radiographic texture analysis has been developed lately to improve the assessment of bone architecture as a determinant of bone quality. We validate here an algorithm for the evaluation of trabecular homogeneity index (HI) in the proximal femur from hip radiographs, with a focus on the impact of the principal compressive system of the trabecular bone, and evaluate its correlation with femoral strength, bone mineral density (BMD), and volumetric trabecular structure parameters. A semiautomatic custom-made algorithm was applied to calculate the HI in the femoral neck and trochanteric areas from radiographs of 178 femoral bone specimens (mean age 79.3 ± 10.4 years). Corresponding neck region was selected in CT scans to calculate volumetric parameters of trabecular structure. The site-specific BMDs were assessed from dual-energy X-ray absorptiometry (DXA), and the femoral strength was experimentally tested in side-impact configuration. Regression analysis was performed between the HI and biomechanical femoral strength, BMD, and volumetric parameters. The correlation between HI and failure load was R(2)  = 0.50; this result was improved to R(2)  = 0.58 for cervical fractures alone. The discrimination of bones with high risk of fractures (load <3000 N) was similar for HI and BMD (AUC = 0.87). Regression analysis between the HIs versus site-specific BMDs yielded R(2)  = 0.66 in neck area, R(2)  = 0.60 in trochanteric area, and an overall of R(2)  = 0.66 for the total hip. Neck HI and BMD correlated significantly with volumetric structure parameters. We present here a method to assess HI that can explain 50% of an experimental failure load and determines bones with high fracture risk with similar accuracy as BMD. The HI also had good correlation with DXA and computed tomography-derived data. PMID:23677814

  6. Difference in Bone Mineral Density Change at the Lateral Femoral Cortices according to Administration of Different Bisphosphonate Agents

    PubMed Central

    Kim, Sungjun; Bang, Hyun Hee; Yoo, Hanna; Lim, Hyunsun; Jung, Woo Seok

    2016-01-01

    Background To retrospectively assess whether the response of subtrochanteric lateral cortex (STLC) is different according to the bisphosphonate agents in terms of bone mineral density (BMD) change. Methods A total of 149 subjects, who had 2- to 4-year interval follow-up of BMD using dual energy X-ray absorptiometry (DXA), were included in this retrospective study divided into following 3 groups: control group (no consumption of any anti-osteoporotic drugs, n=38), alendronate group (naïve alendronate users, n=48), risedronate group (naïve risedronate users, n=63). BMD was measured at the STLC and subtrochanteric medial cortex (STMC) in each patient by drawing rectangular ROIs at the bone cortices. The percent change of BMD at the STLC were compared between the aforementioned 3 groups by using analysis of covariance model to control five independent variables of age, body mass index, percent change of STMC, hip axis length, time interval between DXA examinations. Results The least square mean values±standard deviation of the percent change of BMD in the control, alendronate, and risedronate groups were 1.46±1.50, 2.23±1.26, and 6.96±1.11, respectively. The risedronate group showed significantly higher change of BMD percentage compared with the control (adjusted P=0.012) or alendronate (adjusted P=0.016) groups. Conclusions The percent change of BMD at the STLC in the risedronate user group was greater than the alendronate and control groups. The implication of these changes needs to be further verified. PMID:27294080

  7. Comparison of bone histomorphometry and μCT for evaluating bone quality in tail-suspended rats

    NASA Astrophysics Data System (ADS)

    Sun, Lian-Wen; Huang, Yun-Fei; Wang, Ying; Luan, Hui-Qin; Fan, Yu-Bo

    2014-10-01

    Astronauts often suffer from microgravity-induced osteoporosis due to their time in space. Bone histomorphometry, the 'gold standard' technique for detecting bone quality, is widely used in the evaluation of osteoporosis. This study investigates whether μCT has the same application value as histomorphometry in the evaluation of weightlessness-induced bone loss. A total of 24 SD rats were distributed into three groups (n = 8, each): tail-suspension (TS), TS plus active exercise (TSA), and control (CON). After 21 days, bone mineral density (BMD) was measured by dual energy X-ray absorptiometry (DXA) and μCT, and microstructure was measured by μCT and histomorphometry. BMD was found to have decreased significantly in TS and TSA compared with the CON group. The results of the μCT measurements showed that a change in BMD mainly occurred in the trabecular bone, and the trabecular BMD increased significantly in the TSA compared with the TS group. The comparison of μCT and histomorphometry showed that TS led to a significant decrease in bone volume (BV/TV), trabecular thickness (Tb.Th) and trabecular number (Tb.N), and it led to an increase in trabecular separation (Tb.Sp). However, active exercise can prevent these changes. Significant differences in most parameters between TSA and CON were found by μCT but not by histomorphometry. Additionally, the parameters of these two methods are highly correlated. Therefore, the application value of μCT is as good as histomorphometry and DXA in the diagnosis of weightlessness-induced osteoporosis and is even better in evaluating the efficacy of exercise.

  8. Reference Values for Body Composition and Anthropometric Measurements in Athletes

    PubMed Central

    Santos, Diana A.; Dawson, John A.; Matias, Catarina N.; Rocha, Paulo M.; Minderico, Cláudia S.; Allison, David B.; Sardinha, Luís B.; Silva, Analiza M.

    2014-01-01

    Background Despite the importance of body composition in athletes, reference sex- and sport-specific body composition data are lacking. We aim to develop reference values for body composition and anthropometric measurements in athletes. Methods Body weight and height were measured in 898 athletes (264 female, 634 male), anthropometric variables were assessed in 798 athletes (240 female and 558 male), and in 481 athletes (142 female and 339 male) with dual-energy X-ray absorptiometry (DXA). A total of 21 different sports were represented. Reference percentiles (5th, 25th, 50th, 75th, and 95th) were calculated for each measured value, stratified by sex and sport. Because sample sizes within a sport were often very low for some outcomes, the percentiles were estimated using a parametric, empirical Bayesian framework that allowed sharing information across sports. Results We derived sex- and sport-specific reference percentiles for the following DXA outcomes: total (whole body scan) and regional (subtotal, trunk, and appendicular) bone mineral content, bone mineral density, absolute and percentage fat mass, fat-free mass, and lean soft tissue. Additionally, we derived reference percentiles for height-normalized indexes by dividing fat mass, fat-free mass, and appendicular lean soft tissue by height squared. We also derived sex- and sport-specific reference percentiles for the following anthropometry outcomes: weight, height, body mass index, sum of skinfold thicknesses (7 skinfolds, appendicular skinfolds, trunk skinfolds, arm skinfolds, and leg skinfolds), circumferences (hip, arm, midthigh, calf, and abdominal circumferences), and muscle circumferences (arm, thigh, and calf muscle circumferences). Conclusions These reference percentiles will be a helpful tool for sports professionals, in both clinical and field settings, for body composition assessment in athletes. PMID:24830292

  9. The Benefit of Bone Health by Drinking Coffee among Korean Postmenopausal Women: A Cross-Sectional Analysis of the Fourth & Fifth Korea National Health and Nutrition Examination Surveys

    PubMed Central

    Park, Sang Min; Shin, Doosup; Joh, Hee-Kyung; Cho, Eunyoung

    2016-01-01

    Purpose Although the concern about coffee-associated health problems is increasing, the effect of coffee on osteoporosis is still conflicting. This study aimed to determine the relationship between coffee consumption and bone health in Korean postmenopausal women. Methods A population-based, cross-sectional study was performed using a nationally representative sample of the Korean general population. All 4,066 postmenopausal women (mean age 62.6 years) from the fourth and fifth Korean National Health and Nutrition Examination Survey (2008–2011), who completed the questionnaire about coffee consumption and had data of dual-energy X-ray absorptiometry (DXA) examination. Bone mineral density (BMD) was measured using DXA at the femoral neck and lumbar spine and osteoporosis was defined by World Health Organization T-score criteria in addition to self-report of current anti-osteoporotic medication use. Results After adjusting for various demographic and lifestyle confounders (including hormonal factors), subjects in the highest quartile of coffee intake had 36% lower odds for osteoporosis compared to those in the lowest quartile (Adjusted odds ratio [aOR] = 0.64; 95% confidence interval [CI], 0.43–0.95; P for trend = 0.015). This trend was consistent in osteoporosis of lumbar spine and femoral neck (aOR = 0.65 and 0.55; P for trend = 0.026 and 0.003, respectively). In addition, age- and body mass index (BMI)-adjusted BMD of the femoral neck and lumbar spine increased with higher coffee intake (P for trend = 0.019 and 0.051, respectively). Conclusions Coffee consumption may have protective benefits on bone health in Korean postmenopausal women in moderate amount. Further, prospective studies are required to confirm this association. PMID:26816211

  10. Familial resemblance of body composition, physical activity, and resting metabolic rate in pre-school children

    PubMed Central

    Djafarian, Kurosh; Speakman, John R; Stewart, Joanne; M Jackson, Diane

    2013-01-01

    Background: Although parental obesity is a well-established predisposing factor for the development of obesity, associations between regional body compositions, resting metabolic rates (RMR), and physical activity (PA) of parents and their pre-school children remain unknown. The objective of this study was to investigate parent-child correlations for total and regional body compositions, resting energy expenditures, and physical activity. Methods: Participants were 89 children aged 2-6 years and their parents, consisting of 61 families. Resting metabolic rate was assessed using indirect calorimetry. Total and regional body compositions were measured by both dual energy X-ray absorptiometry (DXA) and deuterium dilution. Physical activity was assessed by an accelerometer. Results: There was a significant parent-offspring regression for total fat free mass (FFM) between children and their mothers (P=0.02), fathers (P=0.02), and mid-parent (average of father and mother value) (P=0.002) when measured by DXA. The same was true for fat mass (FM) between children and mothers (P<0.01), fathers (P=0.02), and mid-parent (P=0.001). There was no significant association between children and parents for physical activity during the entire week, weekend, weekdays, and different parts of days, except for morning activity, which was positively related to the mothers’ morning activities (P<0.01) and mid-parent (P=0.009). No association was found between RMR of children and parents before and after correction for FFM and FM. Conclusion: These data suggest a familial resemblance for total body composition between children and their parents. Our data showed no familial resemblance for PA and RMR between children and their parents. PMID:26989715

  11. Development of an Automated Bone Mineral Density Software Application: Facilitation Radiologic Reporting and Improvement of Accuracy.

    PubMed

    Tsai, I-Ta; Tsai, Meng-Yuan; Wu, Ming-Ting; Chen, Clement Kuen-Huang

    2016-06-01

    The conventional method of bone mineral density (BMD) report production by dictation and transcription is time consuming and prone to error. We developed an automated BMD reporting system based on the raw data from a dual energy X-ray absorptiometry (DXA) scanner for facilitating the report generation. The automated BMD reporting system, a web application, digests the DXA's raw data and automatically generates preliminary reports. In Jan. 2014, 500 examinations were randomized into an automatic group (AG) and a manual group (MG), and the speed of report generation was compared. For evaluation of the accuracy and analysis of errors, 5120 examinations during Jan. 2013 and Dec. 2013 were enrolled retrospectively, and the context of automatically generated reports (AR) was compared with the formal manual reports (MR). The average time spent for report generation in AG and in MG was 264 and 1452 s, respectively (p < 0.001). The accuracy of calculation of T and Z scores in AR is 100 %. The overall accuracy of AR and MR is 98.8 and 93.7 %, respectively (p < 0.001). The mis-categorization rate in AR and MR is 0.039 and 0.273 %, respectively (p = 0.0013). Errors occurred in AR and can be grouped into key-in errors by technicians and need for additional judgements. We constructed an efficient and reliable automated BMD reporting system. It facilitates current clinical service and potentially prevents human errors from technicians, transcriptionists, and radiologists. PMID:26644156

  12. Effects of delaying puberty on bone mineralization in female rats.

    PubMed

    Rakover, Y; Lu, P; Briody, J N; Tao, C; Weiner, E; Ederveen, A G; Cowell, C T; Ben-Shlomo, I

    2000-07-01

    The effect of delaying puberty on bone mineralization was studied using female rats as a model. Repeated injections of gonadotrophin-releasing hormone antagonist (GnRHa) were used to suppress the onset of puberty from the age of 6-10 weeks. A group of control female rats was given aqueous solution injections at the same age and for the same duration. The effect of delaying puberty on bone mineralization was examined using dual energy X-ray absorptiometry (DXA) and peripheral quantitative computerized tomography (QCT), both methods being adapted for small animals. Bone mineral parameters were measured at baseline and at the ages of 10, 17 and 24 weeks in total body, femur and spine. Compared to controls, bone mineral content (BMC) and bone mineral density (BMD), as measured by DXA, were significantly decreased in GnRHa-treated rats in total body and femur at 10 and 24 weeks of age (P < 0.05). The results were even more significant after adjusting for weight. After this adjustment, spine BMC and BMD at 10, 17 and 24 weeks were significantly lower in the treatment group (P < 0.05). Trabecular BMD at the distal femur in the GnRHa treated group as measured by peripheral QCT was significantly lower (P < 0.05). However, cortical bone in the mid-femur had higher BMD, concurrent with lower cortical thickness in the treatment group. In conclusion, a delay in the onset of sexual maturation may cause prolonged, possibly irreversible defect in bone mineralization. PMID:10875850

  13. Wavelet-based signal processing of in vitro ultrasonic measurements at the proximal femur.

    PubMed

    Dencks, Stefanie; Barkmann, Reinhard; Padilla, Frédéric; Haïat, Guillaume; Laugier, Pascal; Glüer, Claus-C

    2007-06-01

    To estimate osteoporotic fracture risk, several techniques for quantitative ultrasound (QUS) measurements at peripheral sites have been developed. As these techniques are limited in the prediction of fracture risk of the central skeleton, such as the hip, we are developing a QUS device for direct measurements at the femur. In doing so, we noticed the necessity to improve the conventional signal processing because it failed in a considerable number of measurements due to multipath transmission. Two sets of excised human femurs (n = 6 + 34) were scanned in transmission mode. Instead of using the conventional methods, the radio-frequency signals were processed with the continuous wavelet transform to detect their time-of-flights for the calculation of speed-of-sound (SOS) in bone. The SOS-values were averaged over a region similar to the total hip region of dual X-ray absorptiometry (DXA) measurements and compared with bone mineral density (BMD) measured with DXA. Testing six standard wavelets, this algorithm failed for only 0% to 6% of scan in test set 1 compared with 29% when using conventional algorithms. For test set 2, it failed for 2% to 12% compared with approximately 40%. SOS and BMD correlated significantly in both test sets (test set 1: r2 = 0.87 to 0.92, p < 0.007; test set 2: r2 = 0.68 to 0.79, p < 0.0001). The correlations are comparable with correlations recently reported. However, the number of evaluable signals could be substantially increased, which improves the perspectives of the in vivo measurements. PMID:17445965

  14. Preliminary study report: topological texture features extracted from standard radiographs of the heel bone are correlated with femoral bone mineral density

    NASA Astrophysics Data System (ADS)

    Boehm, H. F.; Lutz, J.; Koerner, M.; Notohamiprodjo, M.; Reiser, M.

    2009-02-01

    With the growing number of eldery patients in industrialized nations the incidence of geriatric, i.e. osteoporotic fractures is steadily on the rise. It is of great importance to understand the characteristics of hip fractures and to provide diagnostic tests for the assessment of an individual's fracture-risk that allow to take preventive action and give therapeutic advice. At present, bone-mineral-density (BMD) obtained from DXA (dual-energy x-ray-absorptiometry) is the clinical standard of reference for diagnosis and follow-up of osteoporosis. Since availability of DXA - other than that of clinical X-ray imaging - is usually restricted to specialized medical centers it is worth trying to implement alternative methods to estimate an individual's BMD. Radiographs of the peripheral skeleton, e.g. the ankle, range among the most ordered diagnostic procedures in surgery for exclusion or confirmation of fracture. It would be highly beneficial if - as a by-product of conventional imaging - one could obtain a quantitative parameter that is closely correlated with femoral BMD in addition to the original diagnostic information, e.g. fracture status at the peripheral site. Previous studies could demonstrate a correlation between calcaneal BMD and osteoporosis. The objective of our study was to test the hypothesis that topological analysis of calcaneal bone texture depicted by a lateral x-ray projection of the ankle allows to estimate femoral BMD. Our analysis on 34 post-menopausal patients indicate that texture properties based on graylevel topology in calcaneal x-ray-films are closely correlated with BMD at the hip and may qualify as a substitute indicator of femoral fracture risk.

  15. CLINICAL ASSESSMENT OF THE 1/3rd RADIUS USING A NEW DESKTOP ULTRASONIC BONE DENSITOMETER

    PubMed Central

    Stein, Emily M.; Rosete, Fernando; Young, Polly; Kamanda-Kosseh, Mafo; McMahon, Donald J.; Luo, Gangming; Kaufman, Jonathan J.; Shane, Elizabeth; Siffert, Robert S.

    2012-01-01

    The objectives of this study were to evaluate the capability of a novel ultrasound device to clinically estimate bone mineral density (BMD) at the 1/3rd radius. The device rests on a desktop and is portable, and permits real-time evaluation of the radial BMD. The device measures two (2) net time delay (NTD) parameters, NTDDW and NTDCW. NTDDW is defined as the difference between the transit time of an ultrasound pulse to travel through soft-tissue, cortex and medullary cavity, and the transit time through soft tissue only of equal overall distance. NTDCW is defined as the difference between the transit time of an ultrasound pulse to travel through soft-tissue and cortex only, and the transit time through soft tissue only again of equal overall distance. The square root of the product of these two parameters is a measure of the radial BMD at the 1/3rd location as measured by dual-energy x-ray absorptiometry (DXA). A clinical IRB-approved study measured ultrasonically sixty adults at the 1/3rd radius. BMD was also measured at the same anatomical site and time using DXA. A linear regression using NTD produced a linear correlation coefficient of 0.93 (P<0.001). These results are consistent with previously reported simulation and in vitro studies. In conclusion, although x-ray methods are effective in bone mass assessment, osteoporosis remains one of the largest undiagnosed and under-diagnosed diseases in the world today. The research described here should enable significant expansion of diagnosis and monitoring of osteoporosis through a desktop device that ultrasonically assesses bone mass at the 1/3rd radius. PMID:23312957

  16. Effect of body composition on bone mineral density in Moroccan patients with juvenile idiopathic arthritis

    PubMed Central

    El Badri, Dalal; Rostom, Samira; Bouaddi, Ilham; Hassani, Asmae; Chkirate, Bouchra; Amine, Bouchra; Hajjaj-Hassouni, Najia

    2014-01-01

    Introduction The link between bone mass and body composition is widely recognized, but only few works were selectively performed on subjects with juvenile idiopathic arthritis. The aim of our study was to investigate the effect of body composition on bone mineral density (BMD) in Moroccan patients with juvenile idiopathic arthritis. Methods Thirty three children with juvenile idiopathic arthritis (JIA) were included in a cross-sectional study. The diagnosis of JIA was made according to the criteria of the International League of Association of Rheumatology (ILAR). Body mass index (BMI) was calculated from the ratio of weight/height2(kg/m2). Pubertal status was determined according to the Tanner criteria. Bone status, body composition and bone mineral content (BMC) were analyzed by using dual-energy X-ray absorptiometry (DXA). BMD was assessed at the lumbar spine (L1-L4) and at total body in (g/cm2). Total body fat tissue mass (FTM) and lean tissue mass (LTM) were also analyzed by DXA and expressed in kilograms. In children, low BMD was defined as a Z-score less than -2 and osteoporosis was defined as a Z-score less than -2 with a fracture history. Results A cross-sectional study was conducted in 33 Moroccan patients with JIA aged between 4 and 16 years, Fat mass was not related to bone density; in contrast, BMD was positively associated to LTM in total body(r = =0.41, p= 0.04) but not in lumbar spine (r = 0.29, p= 0.17). There exist significant correlation between BMC and BMD in total body (r = 0.51, p = 0.01). Conclusion This study suggests that the LTM is a determining factor of the BMD during adolescence. Other studies with a broader sample would be useful to confirm this relation. PMID:25120859

  17. Gonadal steroid–dependent effects on bone turnover and bone mineral density in men

    PubMed Central

    Finkelstein, Joel S.; Lee, Hang; Leder, Benjamin Z.; Goldstein, David W.; Hahn, Christopher W.; Hirsch, Sarah C.; Linker, Alex; Perros, Nicholas; Servais, Andrew B.; Taylor, Alexander P.; Webb, Matthew L.; Youngner, Jonathan M.; Yu, Elaine W.

    2016-01-01

    BACKGROUND. Severe gonadal steroid deficiency induces bone loss in adult men; however, the specific roles of androgen and estrogen deficiency in hypogonadal bone loss are unclear. Additionally, the threshold levels of testosterone and estradiol that initiate bone loss are uncertain. METHODS. One hundred ninety-eight healthy men, ages 20–50, received goserelin acetate, which suppresses endogenous gonadal steroid production, and were randomized to treatment with 0, 1.25, 2.5, 5, or 10 grams of testosterone gel daily for 16 weeks. An additional cohort of 202 men was randomized to receive these treatments plus anastrozole, which suppresses conversion of androgens to estrogens. Thirty-seven men served as controls and received placebos for goserelin and testosterone. Changes in bone turnover markers, bone mineral density (BMD) by dual-energy x-ray absorptiometry (DXA), and BMD by quantitative computed tomography (QCT) were assessed in all men. Bone microarchitecture was assessed in 100 men. RESULTS. As testosterone dosage decreased, the percent change in C-telopeptide increased. These increases were considerably greater when aromatization of testosterone to estradiol was also suppressed, suggesting effects of both testosterone and estradiol deficiency. Decreases in DXA BMD were observed when aromatization was suppressed but were modest in most groups. QCT spine BMD fell substantially in all testosterone-dose groups in which aromatization was also suppressed, and this decline was independent of testosterone dose. Estradiol deficiency disrupted cortical microarchitecture at peripheral sites. Estradiol levels above 10 pg/ml and testosterone levels above 200 ng/dl were generally sufficient to prevent increases in bone resorption and decreases in BMD in men. CONCLUSIONS. Estrogens primarily regulate bone homeostasis in adult men, and testosterone and estradiol levels must decline substantially to impact the skeleton. TRIAL REGISTRATION. ClinicalTrials.gov, NCT00114114

  18. Development and Internal Validation of the Male Osteoporosis Risk Estimation Score

    PubMed Central

    Shepherd, Angela J.; Cass, Alvah R.; Carlson, Carol A.; Ray, Laura

    2007-01-01

    PURPOSE We wanted to develop and validate a clinical prediction rule to identify men at risk for osteoporosis and subsequent hip fracture who might benefit from dual-energy x-ray absorptiometry (DXA). METHODS We used risk factor data from the National Health and Nutrition Examination Survey III to develop a best fitting multivariable logistic regression model in men aged 50 years and older randomized to either the development (n = 1,497) or validation (n = 1,498) cohorts. The best fitting model was transformed into a simplified scoring algorithm, the Male Osteoporosis Risk Estimation Score (MORES). We validated the MORES, comparing sensitivity, specificity, and area under the receiver operating characteristics (ROC) curve in the 2 cohorts and assessed clinical utility with an analysis of the number needed-to-screen (NNS) to prevent 1 additional hip fracture. RESULTS The MORES included 3 variables—age, weight, and history of chronic obstructive pulmonary disease—and showed excellent predictive validity in the validation cohort. A score of 6 or greater yielded an overall sensitivity of 0.93 (95% CI, 0.85–0.97), a specificity of 0.59 (95% CI, 0.56–0.62), and an area under the ROC curve of 0.832 (95% CI, 0.807–0.858). The overall NNS to prevent 1 additional hip fracture was 279 in a cohort of men representative of the US population. CONCLUSIONS Osteoporosis is a major predictor of hip fractures. Experts believe bisphosphonate treatment in men should yield results similar to that in women and reduce hip fracture rates associated with osteoporosis. In men aged 60 years and older, the MORES is a simple approach to identify men at risk for osteoporosis and refer them for confirmatory DXA scans. PMID:18025492

  19. Assessment of Lean Mass and Physical Performance in Sarcopenia.

    PubMed

    Cawthon, Peggy M

    2015-01-01

    This review provides a description of the assessment of lean mass and physical performance with particular attention to how these measures are used in the context of sarcopenia, in both research and clinical settings. One of the most common methods to estimate muscle mass is whole-body dual-energy X-ray absorptiometry (DXA). DXA estimates the total amount of lean tissue but does not directly measure muscle mass. Appendicular lean mass (ALM), derived from DXA scans, is the sum of the lean tissue in the arms and legs. ALM alone, or scaled to height squared (ALM/height(2)) or body mass index (ALM/body mass index), is the most common metric used as an approximation of muscle mass in sarcopenia research. Other methods to assess muscle mass include central or peripheral quantitative computed tomography (to determine muscle cross-sectional area and muscle density, a marker of fat i nfiltration into the muscle); magnetic resonance (to assess muscle cross-sectional area and volume); and bioelectrical impedance analysis (to determine fat-free mass). Many approaches to objectively measuring physical performance have been used in sarcopenia research. Muscle strength is often measured: Grip strength is very inexpensive and straightforward to assess, whereas assessment of lower extremity strength is more difficult. However, lower extremity strength may be a more relevant measure than grip strength in the context of mobility outcomes. Dynamic physical performance is also widely measured in research settings and may be emerging as a routine assessment in clinical care. The most widely used measure of physical performance is walking speed over a short distance, usually 3-6 m. Other measures of objective physical performance include the Short Physical Performance Battery that includes gait speed, ability and time to rise from a chair 5 times, and static balance tests; and the Timed Up and Go test that measures the time to rise from a chair and walk a short distance. Finally, longer

  20. Effect of Body Composition Methodology on Heritability Estimation of Body Fatness

    PubMed Central

    Elder, Sonya J.; Roberts, Susan B.; McCrory, Megan A.; Das, Sai Krupa; Fuss, Paul J.; Pittas, Anastassios G.; Greenberg, Andrew S.; Heymsfield, Steven B.; Dawson-Hughes, Bess; Bouchard, Thomas J.; Saltzman, Edward; Neale, Michael C.

    2014-01-01

    Heritability estimates of human body fatness vary widely and the contribution of body composition methodology to this variability is unknown. The effect of body composition methodology on estimations of genetic and environmental contributions to body fatness variation was examined in 78 adult male and female monozygotic twin pairs reared apart or together. Body composition was assessed by six methods – body mass index (BMI), dual energy x-ray absorptiometry (DXA), underwater weighing (UWW), total body water (TBW), bioelectric impedance (BIA), and skinfold thickness. Body fatness was expressed as percent body fat, fat mass, and fat mass/height2 to assess the effect of body fatness expression on heritability estimates. Model-fitting multivariate analyses were used to assess the genetic and environmental components of variance. Mean BMI was 24.5 kg/m2 (range of 17.8–43.4 kg/m2). There was a significant effect of body composition methodology (p<0.001) on heritability estimates, with UWW giving the highest estimate (69%) and BIA giving the lowest estimate (47%) for fat mass/height2. Expression of body fatness as percent body fat resulted in significantly higher heritability estimates (on average 10.3% higher) compared to expression as fat mass/height2 (p=0.015). DXA and TBW methods expressing body fatness as fat mass/height2 gave the least biased heritability assessments, based on the small contribution of specific genetic factors to their genetic variance. A model combining DXA and TBW methods resulted in a relatively low FM/ht2 heritability estimate of 60%, and significant contributions of common and unique environmental factors (22% and 18%, respectively). The body fatness heritability estimate of 60% indicates a smaller contribution of genetic variance to total variance than many previous studies using less powerful research designs have indicated. The results also highlight the importance of environmental factors and possibly genotype by environmental

  1. A comparison of field methods to assess body composition in a diverse group of sedentary women.

    PubMed

    D'Alonzo, Karen T; Aluf, Ana; Vincent, Linda; Cooper, Kristin

    2009-01-01

    Accurate assessment of body composition is essential in the evaluation of obesity. While laboratory methods are commonly used to assess fat mass, field measures (e.g., skinfold thickness [SKF] and bioelectrical impedance [BIA]) may be more practical for screening large numbers of individuals in intervention studies. In this study, a correlational design was used among 46 racially and ethnically diverse, sedentary women (mean age = 25.73 years) to (a) compare the percentage of body fat as determined by SKF and the upper body BIA and (b) examine the effects of body mass index (BMI), racial/ethnic background, age, and stage of the menstrual cycle on differences in the estimated percentage of body fat obtained using the SKF and BIA. Overall, a significant correlation between SKF and BIA (r = .98, p < .001) was found, with similar findings among Black, Hispanic and White non-Hispanic women. The mean differences between BIA and SKF were not significantly correlated with BMI, age, race/ethnicity or stage of the menstrual cycle. Data from this study suggest that BIA showed similar body fat prediction values compared with SKF and may be a viable alternative to SKF among diverse groups of healthy women. Additional testing and comparison of these field methods with the laboratory methods of hydro-densitometry or dual energy X-ray absorptiometry is recommended to further determine whether BIA devices can be routinely recommended as an alternative to the SKF. PMID:19022781

  2. MRI-derived bound and pore water concentrations as predictors of fracture resistance.

    PubMed

    Manhard, Mary Kate; Uppuganti, Sasidhar; Granke, Mathilde; Gochberg, Daniel F; Nyman, Jeffry S; Does, Mark D

    2016-06-01

    Accurately predicting fracture risk in the clinic is challenging because the determinants are multi-factorial. A common approach to fracture risk assessment is to combine X-ray-based imaging methods such as dual-energy X-ray absorptiometry (DXA) with an online Fracture Risk Assessment Tool (FRAX) that includes additional risk factors such as age, family history, and prior fracture incidents. This approach still does not adequately diagnose many individuals at risk, especially those with certain diseases like type 2 diabetes. As such, this study investigated bound water and pore water concentrations (Cbw and Cpw) from ultra-short echo time (UTE) magnetic resonance imaging (MRI) as new predictors of fracture risk. Ex vivo cadaveric arms were imaged with UTE MRI as well as with DXA and high-resolution micro-computed tomography (μCT), and imaging measures were compared to both whole-bone structural and material properties as determined by three-point bending tests of the distal-third radius. While DXA-derived areal bone mineral density (aBMD) and μCT-derived volumetric BMD correlated well with structural strength, they moderately correlated with the estimate material strength with gender being a significant covariate for aBMD. MRI-derived measures of Cbw and Cpw had a similar predictive ability of material strength as aBMD but did so independently of gender. In addition, Cbw was the only imaging parameter to significantly correlate with toughness, the energy dissipated during fracture. Notably, the strength of the correlations with the material properties of bone tended to be higher when a larger endosteal region was used to determine Cbw and Cpw. These results indicate that MRI measures of Cbw and Cpw have the ability to probe bone material properties independent of bone structure or subject gender. In particular, toughness is a property of fracture resistance that is not explained by X-ray based methods. Thus, these MRI-derived measures of Cbw and Cpw in cortical

  3. Prediction of absolute risk of fragility fracture at 10 years in a Spanish population: validation of the WHO FRAX ™ tool in Spain

    PubMed Central

    2011-01-01

    Background Age-related bone loss is asymptomatic, and the morbidity of osteoporosis is secondary to the fractures that occur. Common sites of fracture include the spine, hip, forearm and proximal humerus. Fractures at the hip incur the greatest morbidity and mortality and give rise to the highest direct costs for health services. Their incidence increases exponentially with age. Independently changes in population demography, the age - and sex- specific incidence of osteoporotic fractures appears to be increasing in developing and developed countries. This could mean more than double the expected burden of osteoporotic fractures in the next 50 years. Methods/Design To assess the predictive power of the WHO FRAX™ tool to identify the subjects with the highest absolute risk of fragility fracture at 10 years in a Spanish population, a predictive validation study of the tool will be carried out. For this purpose, the participants recruited by 1999 will be assessed. These were referred to scan-DXA Department from primary healthcare centres, non hospital and hospital consultations. Study population: Patients attended in the national health services integrated into a FRIDEX cohort with at least one Dual-energy X-ray absorptiometry (DXA) measurement and one extensive questionnaire related to fracture risk factors. Measurements: At baseline bone mineral density measurement using DXA, clinical fracture risk factors questionnaire, dietary calcium intake assessment, history of previous fractures, and related drugs. Follow up by telephone interview to know fragility fractures in the 10 years with verification in electronic medical records and also to know the number of falls in the last year. The absolute risk of fracture will be estimated using the FRAX™ tool from the official web site. Discussion Since more than 10 years ago numerous publications have recognised the importance of other risk factors for new osteoporotic fractures in addition to low BMD. The extension of a

  4. Field method to measure changes in percent body fat of young women: The TIGER Study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Body mass index (BMI), waist (W) and hip (H) circumference (C) are commonly used to assess changes in body composition for field research. We developed a model to estimate changes in dual energy X-ray absorption (DXA) percent fat (% fat) from these variables with a diverse sample of young women fro...

  5. Comparison of five body-composition methods in peritoneal dialysis patients.

    PubMed

    Stall, S H; Ginsberg, N S; DeVita, M V; Zabetakis, P M; Lynn, R I; Gleim, G W; Wang, J; Pierson, R N; Michelis, M F

    1996-08-01

    Body-composition assessment is an important method of evaluating nutritional status in peritoneal dialysis patients. Because body-composition measurement estimates have not been fully validated in this population, we assessed five body-composition methods in 30 well-dialyzed peritoneal dialysis patients. The techniques studied included bioelectrical impedance analysis, dual-energy X-ray absorptiometry, total-body potassium counting, and anthropometry by two techniques. The dialysis patients were matched for age, race, sex, height, weight, and body mass index with 29 healthy control subjects in our laboratory database. By 5 x 2 x 2 analysis of variance, significant differences were found between results by modality (P < 0.0001) as well as by sex, with women having an increased percentage of fat (P < 0.0001). However, there was no significant intermethod difference by condition (peritoneal dialysis or control). That is, although significantly different percentage fat values were found between the body-composition techniques, this variability was independent of whether the measurement was made on control or peritoneal dialysis patients. Despite the differences between modalities, all techniques were found to correlate significantly with each other (P < 0.01 or better for men and P < 0.001 or better for women). Our experience shows that these routine techniques for measuring body composition can be readily applied to stable peritoneal dialysis patients. PMID:8694010

  6. Qualitative and quantitative assessment of bone fragility and fracture healing using conventional radiography and advanced imaging technologies--focus on wrist fracture.

    PubMed

    Firoozabadi, Reza; Morshed, Saam; Engelke, Klaus; Prevrhal, Sven; Fierlinger, Anke; Miclau, Theodore; Genant, Harry K

    2008-09-01

    Fractures of the distal radius are one of the most common injuries presented to orthopaedic surgeons. A variety of treatment options are available for the vast array of fracture patterns. Research that explores bone fragility and fracture healing has led to new treatment modalities. As new products and methods are derived to aid in fracture healing it is essential to develop noninvasive and/or nondestructive techniques to assess structural information about bone. Quantitative assessment of macro-structural characteristics such as geometry, and microstructural features such as relative trabecular volume, trabecular spacing, and connectivity may improve our ability to estimate bone strength. Methods for quantitatively assessing macrostructure include (besides conventional radiographs) dual x-ray absorptiometry (DXA) and computed tomography (CT), particularly volumetric quantitative computed tomography (vQCT). Methods for assessing microstructure of trabecular bone include high resolution computed tomography (hrCT), micro computed tomography (microCT), high resolution magnetic resonance (hrMR), and micro magnetic resonance microMR. Volumetric QCT, hrCT and hrMR are generally applicable in vivo; microCT and microMR are principally applicable in vitro. Clinically, the challenges for bone imaging include balancing the advantages of simple bone densitometry versus the more complex architectural features of bone, or the deeper research requirements versus the broader clinical needs. PMID:18753895

  7. Histological analysis of cells and matrix mineralization of new bone tissue induced in rabbit femur bones by Mg-Zr based biodegradable implants.

    PubMed

    Ragamouni, Sravanthi; Kumar, Jerald Mahesh; Mushahary, Dolly; Nemani, Harishankar; Pande, Gopal

    2013-09-01

    The biological efficacy of bone inducing implant materials in situ can be assessed effectively by performing histological analysis. We studied the peri-implant bone regeneration around two types of biodegradable magnesium-zirconium alloys, Mg-5Zr and Mg-Zr-2Sr, using histological, histochemical and immunohistochemical methods in the femur of New Zealand White strain rabbits. Our study includes three animal groups: (a) Mg-5Zr, (b) Mg-Zr-2Sr and (c) control. In each group three animals were used and in groups 'a' and 'b' the respective alloys were implanted in cavities made at the distal ends of the femur; control animals were left without implants to observe natural bone healing. Qualitative assessment of the cellularity and matrix mineralization events of the newly formed bone tissue was done at three months after implantation by histological methods in methyl methacrylate embedded tissue without decalcifying the bone. Quantitative mineral content and density of the new bone (NB) were evaluated by the statistical analysis of dual energy X-ray absorptiometry (DXA) data obtained from three animals in each experimental group. Based on our analysis we conclude that Mg-Zr-2Sr alloy showed better osseointegration of the newly formed bone with the implant surface. Our methodology of studying peri-implant osteoinduction of degradable implants using low temperature methyl methacrylate embedding resin can be useful as a general method for determining the bio-efficacy of implant materials. PMID:23628266

  8. A phase I feasibility study of multi-modality imaging assessing rapid expansion of marrow fat and decreased bone mineral density in cancer patients

    PubMed Central

    Hui, Susanta K; Arentsen, Luke; Sueblinvong, Thanasak; Brown, Keenan; Bolan, Pat; Ghebre, Rahel G; Downs, Levi; Shanley, Ryan; Hansen, Karen E.; Minenko, Anne G.; Takhashi, Yutaka; Yagi, Masashi; Zhang, Yan; Geller, Melissa; Reynolds, Margaret; Lee, Chung K; Blaes, Anne H.; Allen, Sharon; Zobel, Bruno Beomonte; Le, Chap; Froelich, Jerry; Rosen, Clifford; Yee, Douglas

    2014-01-01

    Purpose Cancer survivors are at an increased risk for fractures, but lack of effective and economical biomarkers limits quantitative assessments of marrow fat (MF), bone mineral density (BMD) and their relation in response to cytotoxic cancer treatment. We report dual energy CT (DECT) imaging, commonly used for cancer diagnosis, treatment and surveillance, as a novel biomarker of MF and BMD. Methods We validated DECT in pre-clinical and Phase I clinical trials and verified with water-fat MRI (WF-MRI), quantitative CT (QCT) and dual-energy X-ray absorptiometry (DXA). Basis material composition framework was validated using water and small-chain alcohols simulating different components of bone marrow. Histologic validation was achieved by measuring percent adipocyte in cadaver vertebrae and compared with DECT and WF-MRI. For a Phase I trial, sixteen patients with gynecologic malignancies (treated with oophorectomy, radiotherapy or chemotherapy) underwent DECT, QCT, WF-MRI and DXA before and 12 months after treatment. BMD and MF percent and distribution were quantified in lumbar vertebrae and the right femoral neck. Results Measured precision (3 mg/cm3) was sufficient to distinguish test solutions. Adiposity in cadaver bone histology was highly correlated with MF measured using DECT and WF-MRI (r = 0.80 and 0.77, respectively). In the clinical trial, DECT showed high overall correlation (r = 0.77, 95% CI: 0.69, 0.83) with WF-MRI. MF increased significantly after treatment (p<0.002). Chemotherapy and radiation caused greater increases in MF than oophorectomy (p<0.032). L4 BMD decreased 14% by DECT, 20% by QCT, but only by 5% by DXA (p<0.002 for all). At baseline, we observed a statistically significant inverse association between MF and BMD which was dramatically attenuated after treatment. Conclusion Our study demonstrated that DECT, similar to WF-MRI, can accurately measure marrow adiposity. Both imaging modalities show rapid increase in MF following cancer treatment

  9. Subcutaneous and Segmental Fat Loss with and without Supportive Supplements in Conjunction with a Low-Calorie High Protein Diet in Healthy Women

    PubMed Central

    Falcone, Paul H.; Tai, Chih Yin; Carson, Laura R.; Joy, Jordan M.; Mosman, Matt M.; Vogel, Roxanne M.; McCann, Tyler R.; Crona, Kevin P.; Griffin, J. Daniel; Kim, Michael P.; Moon, Jordan R.

    2015-01-01

    Background Weight loss benefits of multi-ingredient supplements in conjunction with a low-calorie, high-protein diet in young women are unknown. Therefore, the purpose of this study was to investigate the effects of a three-week low-calorie diet with and without supplementation on body composition. Methods Thirty-seven recreationally-trained women (n = 37; age = 27.1 ± 4.2; height = 165.1 ± 6.4; weight = 68.5 ± 10.1; BMI = 25.1 ± 3.4) completed one of the following three-week interventions: no change in diet (CON); a high-protein, low-calorie diet supplemented with a thermogenic, conjugated linoleic acid (CLA), a protein gel, and a multi-vitamin (SUP); or the high-protein diet with isocaloric placebo supplements (PLA). Before and after the three-week intervention, body weight, %Fat via dual X-ray absorptiometry (DXA), segmental fat mass via DXA, %Fat via skinfolds, and skinfold thicknesses at seven sites were measured. Results SUP and PLA significantly decreased body weight (SUP: PRE, 70.47 ± 8.01 kg to POST, 67.51 ± 8.10 kg; PLA: PRE, 67.88 ± 12.28 kg vs. POST, 66.38 ± 11.94 kg; p ≤ 0.05) with a greater (p ≤ 0.05) decrease in SUP than PLA or CON. SUP and PLA significantly decreased %Fat according to DXA (SUP: PRE, 34.98 ± 7.05% to POST, 32.99 ± 6.89%; PLA: PRE, 34.22 ± 6.36% vs. POST, 32.69 ± 5.84%; p ≤ 0.05), whereas only SUP significantly decreased %Fat according to skinfolds (SUP: PRE, 27.40 ± 4.09% to POST, 24.08 ± 4.31%; p ≤ 0.05). SUP significantly (p ≤ 0.05) decreased thicknesses at five skinfolds (chest, waist, hip, subscapular, and tricep) compared to PLA, but not at two skinfolds (axilla and thigh). Conclusions The addition of a thermogenic, CLA, protein, and a multi-vitamin to a three-week low-calorie diet improved weight loss, total fat loss and subcutaneous fat loss, compared to diet alone. PMID:25875200

  10. Evaluation of Trabecular Micro-Architecture in Non-Osteoporotic Post-Menopausal Women With and Without Fracture

    PubMed Central

    Kijowski, Richard; Tuite, Michael; Kruger, Diane; Del Rio, Alejandro Munoz; Kleerekoper, Michael; Binkley, Neil

    2012-01-01

    Purpose To compare microscopic magnetic resonance imaging (μMRI) parameters of trabecular micro-architecture between postmenopausal women with and without fracture who have normal or osteopenic bone mineral density (BMD) on dual-energy x-ray absorptiometry (DXA). Methods The study included 36 post-menopausal Caucasian women 50 years of age and older with normal or osteopenic BMD (T-scores better than −2.5 at the lumbar spine, proximal femur, and one-third radius on DXA). Eighteen women had a history of low-energy fracture, while 18 women had no history of fracture and served as an age, race, and ultra-distal radius BMD-matched control group. A three-dimensional fast large-angle spin-echo (FLASE) sequence with 137 μm × 137 μm × 400 μm resolution was performed through the non-dominant wrist of all 36 women using the same 1.5T scanner. The high resolution images were used to measure trabecular bone volume fraction, trabecular thickness, surface-to-curve ratio, and erosion index. Wilcoxon signed rank tests were used to compare differences in BMD and μMRI parameters between post-menopausal women with and without fracture. Results Post-menopausal women with fracture had significantly lower (p<0.05) trabecular bone volume fraction and surface-to-curve ratio and significantly higher (p<0.05) erosion index than post-menopausal women without fracture. There was no significant difference between post-menopausal women with and without fracture in trabecular thickness (p=0.80) and BMD of the spine (p=0.21), proximal femur (p=0.19), one-third radius (p=0.47), and ultra-distal radius (p=0.90). Conclusions Post-menopausal women with normal or osteopenic BMD who had a history of low energy fracture had significantly different (p<0.05) μMRI parameters than an age, race, and ultra-distal radius BMD-matched control group of postmenopausal women with no history of fracture. Our study suggests that μMRI can be used to identify individuals without a DXA-based diagnosis of

  11. Use of MR-based trabecular bone microstructure analysis at the distal radius for osteoporosis diagnostics: a study in post-menopausal women with breast cancer and treated with aromatase inhibitor

    PubMed Central

    Baum, Thomas; Karampinos, Dimitrios C.; Seifert-Klauss, Vanadin; Pencheva, Tsvetelina D.; Jungmann, Pia M.; Rummeny, Ernst J.; Müller, Dirk; Bauer, Jan S.

    2016-01-01

    Summary Purpose Treatment with aromatase inhibitor (AI) is recommended for post-menopausal women with hormone-receptor positive breast cancer. However, AI therapy is known to induce bone loss leading to osteoporosis with an increased risk for fragility fractures. The purpose of this study was to investigate whether changes of magnetic resonance (MR)-based trabecular bone microstructure parameters as advanced imaging biomarker can already be detected in subjects with AI intake but still without evidence for osteoporosis according to dual energy X-ray absorptiometry (DXA)-based bone mineral density (BMD) measurements as current clinical gold standard. Methods Twenty-one postmenopausal women (62±6 years of age) with hormone-receptor positive breast cancer, ongoing treatment with aromatase inhibitor for 23±15 months, and no evidence for osteoporosis (current DXA T-score greater than −2.5) were recruited for this study. Eight young, healthy women (24±2 years of age) were included as controls. All subjects underwent 3 Tesla magnetic resonance imaging (MRI) of the distal radius to assess the trabecular bone microstructure. Results Trabecular bone microstructure parameters were not significantly (p>0.05) different between subjects with AI intake and controls, including apparent bone fraction (0.42±0.03 vs. 0.42±0.05), trabecular number (1.95±0.10 mm−1 vs 1.89±0.15 mm−1), trabecular separation (0.30±0.03 mm vs 0.31±0.06 mm), trabecular thickness (0.21±0.01 mm vs 0.22±0.02 mm), and fractal dimension (1.70±0.02 vs. 1.70±0.03). Conclusion These findings suggest that the initial deterioration of trabecular bone microstructure as measured by MRI and BMD loss as measured by DXA occur not sequentially but rather simultaneously. Thus, the use of MR-based trabecular bone microstructure assessment is limited as early diagnostic biomarker in this clinical setting. PMID:27252740

  12. Improving Osteoporosis Management in Primary Care: An Audit of the Impact of a Community Based Fracture Liaison Nurse

    PubMed Central

    Chan, Tom

    2015-01-01

    Background Osteoporosis and associated fragility fractures are a major health problem; they are more common in women over 50 years old. Fracture liaison nurses have been widely used in secondary care to promote the recognition of fragility fractures and to promote the use of bone-sparing medication to reduce the risk of recurrent facture. Objective Audit the impact of a primary care based fracture liaison nurse on the detection of fragility fractures in people with osteoporosis and their treatment with a bone-sparing medication. Method This audit took place in 12 GP practices using ‘before and after’ cross-sectional extractions of anonymised routine data. We report, for females 50–74 years and ≥75 years old, socio-economic deprivation index, the prevalence of osteoporosis, recording of fragility fractures, dual-energy X-ray absorptiometry (DXA), smoking, and body-mass index (BMI) and use of appropriate bone-sparing medication. We used Altman’s test of independent proportions to compare before and after data. Results Recording of the diagnosis of osteoporosis increased from 1.5% to 1.7% (p = 0.059); the rate of DXA scans fell (1.8% to 1.4%; p = 0.002); recording of fractures and fragility fractures more than doubled (0.8% to 2.0%; p<0.001 and 0.5% to 1.5%; p<0.001, respectively) with approximate doubling of the recording of smoking, and BMI (p<0.001 level). Fragility fracture recording rose from 8.8% to 15% in females aged 50 to 74, and from 0.8% to 2.3% in people aged ≥75years old (p<0.001). There appeared to be inequity in the service, people who were least deprived were more likely to receive DXA scans and the more deprived to be prescribed bone sparing agents. Conclusion A fracture liaison nurse in primary care has been associated with a period of improved management. Liaison nurses based in different parts of the health system should be tested in a prospective trial. PMID:26313924

  13. Commonality versus specificity among adiposity traits in normal-weight and moderately overweight adults

    PubMed Central

    Raja, GK; Sarzynski, MA; Katzmarzyk, PT; Johnson, WD; Tchoukalova, Y; Smith, SR; Bouchard, C

    2014-01-01

    BACKGROUND Many adiposity traits have been related to health complications and premature death. These adiposity traits are intercorrelated but their underlying structure has not been extensively investigated. We report on the degree of commonality and specificity among multiple adiposity traits in normal-weight and moderately overweight adult males and females (mean body mass index (BMI) = 22.9 kg m−2, s.d. = 2.4). METHODS A total of 75 healthy participants were assessed for a panel of adiposity traits including leg, arm, trunk, total fat masses and visceral adipose tissue (VAT) derived from dual energy X-ray absorptiometry (DXA), hepatic and muscle lipids from proton magnetic resonance spectroscopy, fat cell volume from an abdominal subcutaneous adipose tissue biopsy (n = 36) and conventional anthropometry (BMI and waist girth). Spearman’s correlations were calculated and were subjected to factor analysis. RESULTS Arm, leg, trunk and total fat masses correlated positively (r = 0.78–0.95) with each other. VAT correlated weakly with fat mass indicators (r = 0.24–0.31). Intrahepatic lipids (IHL) correlated weakly with all fat mass traits (r = 0.09–0.34), whereas correlations between DXA depots and intramyocellular lipids (IMCL) were inconsequential. The four DXA fat mass measures, VAT, IHL and IMCL depots segregated as four independent factors that accounted for 96% of the overall adiposity variance. BMI and waist girth were moderately correlated with the arm, leg, trunk and total fat and weakly with VAT, IHL and IMCL. CONCLUSION Adiposity traits share a substantial degree of commonality, but there is considerable specificity across the adiposity variance space. For instance, VAT, IHL and IMCL are typically poorly correlated with each other and are poorly to weakly associated with the other adiposity traits. The same is true for BMI and waist girth, commonly used anthropometric indicators of adiposity. These results do not support the view that it will be

  14. Evolution and predictors of change in total bone mineral density over time in HIV-infected men and women in the Nutrition for Healthy Living Study

    PubMed Central

    Jacobson, DL; Spiegelman, D; Knox, TK; Wilson, IB

    2014-01-01

    Background Osteopenia is common in the era of effective antiretroviral therapy (ART), yet the etiology is unclear. We evaluated the association of host factors, disease severity and ART to changes in total body bone mineral density (Total BMD) over time in HIV-infected men (n=283) and women (n=96). Methods Total BMD was measured annually by whole body dual energy absorptiometry (DXA) and medical, dietary and behavioral history was collected. The median time from first to last DXA was 2.5 years (range 0.9 to 6.8). Using a repeated measures regression model, we identified variables independently associated with percent change in Total BMD between consecutive DXA exams (n=799 intervals), adjusted for age, race, sex, menopause and smoking. We estimated percent change in Total BMD over an average interval (one year) standardized for representative levels of each determinant in males, pre- and post-menopausal women. Results Median baseline age, CD4 and viral load were 42 years, 364 cells/mm3 and 2.7 log10 copies/ml, respectively. The estimated change in Total BMD for those not on ART was −0.37%/yr (95%CI −0.76, −0.02) for men, −0.08%/yr (95%CI −0.49, 0.33) for pre-menopausal women and −1.07%/yr (95%CI −1.86, −0.28) for post-menopausal women. Greater loss of Total BMD was associated with lower albumin, lower BMI, prednisone/hydrocortisone use, tenofovir use and longer duration of ddI. Strength training and long duration of d4T and saquinavir prevented or mitigated bone loss. For those on ART for 3 years (not including the above agents), the rate of loss was −0.57%/yr (95%CI −1.00, −0.14) for men, −0.28% (95%CI −0.71, 0.15 ) for pre-menopausal women and −1.27% (95%CI −2.07, −0.47) for post menopausal women. Post-menopausal women had greater loss than pre-menopausal women and men. Conclusion Low body weight, low albumin, catabolic steroid use and menopause may accelerate bone loss, and strength training may be protective. Tenofovir and dd

  15. Commentary: Concurrent administration of PTH and antiresorptives: Additive effects or DXA cosmetics.

    PubMed

    Eriksen, Erik Fink; Brown, Jacques P

    2016-05-01

    Osteoanabolic therapy with parathyroid hormone (PTH(1-84)) or the PTH analogues teriparatide (PTH(1-34), TPTD) and abaloparatide induces a positive remodeling balance and increases modeling and remodeling activity on bone surfaces. As the anabolic action of PTH is primarily remodeling based increased bone turnover maximizes bone accrual. Increased remodeling, however, also increases cortical porosity and reduces mineralization of newly formed bone, which may cause initial reductions in BMD, particularly at sites rich in cortical bone. Increased cortical porosity may also have negative consequences for bone strength. Consequently, an interest developed in concurrent therapies offsetting the potential early negative cortical bone effects developed, and several studies using varying concurrent combinations of TPTD or PTH(1-84) with various antiresorptive (anti-catabolic) agents (estrogen, SERMs, bisphosphonates and denosumab) have been published. This commentary addresses the discrepancy between changes in areal bone mineral density (BMD) and bone turnover markers (BTM) in concurrent therapy studies leading to possible misinterpretations of the results. In studies of concurrent therapies increases in BMD are generally accompanied by decreases in biochemical markers of bone turnover. This includes Procollagen Type I N-Terminal Propetide (PINP), which has emerged as a reliable marker of bone formation during osteoanabolic therapy. We therefore want to submit, that the larger increases in BMD seen initially in patients on concurrent therapy mask the potential for later reduced osteoanabolic action of PTH. This notion is corroborated by: 1) the lesser impairment of bone anabolism seen with milder antiresorptive modalities like hormone replacement therapy (HRT) or Selective Estrogen Receptor Modulators (SERMs); 2) the changes in BMD seen in extension studies where treatment naïve patients previously treated with PTH alone are crossed over to antiresorptive drugs. We therefore advise against a general use of concurrent therapy with PTH and antiresorptive agents, as it entails blunting of osteoanabolic action of PTH in the long run. PMID:26944033

  16. The use of NMR for infant body composition, comparison with DXA and chemical analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Childhood obesity is susceptible to programming during the early stages of development (in utero and/or during the first year of life). Obtaining accurate and precise measures of body composition (BC) in infants and children and through adulthood is critical to testing these hypotheses in both cross...

  17. The Use of NMR for Infant Body Composition, Comparison with DXA and Chemical Analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Childhood obesity is susceptible to programming during the early stages of development (in utero and/or during the first year of life). Obtaining accurate and precise measures of body composition (BC) in infants and children and through adulthood is critical to testing these hypotheses in both cross...

  18. Strain-induced crack formations in PDMS/DXA drug collars.

    PubMed

    Warner, J A; Polkinghorne, J C; Gonerka, J; Meyer, S; Luo, B; Frethem, C; Haugstad, G

    2013-07-01

    Drug-eluting systems are currently used in cardiac leads in order to reduce inflammation and fibrosis at the lead-tissue interface. Drug release from these drug delivery systems can be modulated by the manufacturing processes used to create the drug systems and assemble them onto the cardiac lead. In this study, scanning electron microscopy, atomic force microscopy and Raman microscopy are employed to explore the material characteristics of a polydimethylsiloxane-dexamethasone acetate drug collar used on cardiac leads when varying the strain during collar assembly on the lead. A novel test fixture was created in order to investigate these drug collars under simulated stresses. Measurements of the collar while fitted to a rod revealed microcracks that are hypothesized to affect the drug release performance, resulting in increased drug elution. It was found that the strain that occurs during assembly of the collar onto the lead is a key factor in the formation of these microcracks. Results also suggest that cracks tend to form in areas of high drug particle density, and propagate between drug particles. PMID:23541599

  19. Cross-validation and calibration of Jackson-Pollock equations with DXA: the TIGER study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Jackson-Pollock (J&P) body composition equations were developed primarily from data on white men and women using hydrostatically determined body density (BD) as the criterion measure. This study cross-validated the J&P equations with ethnically diverse subjects and percent fat (%fat) determined ...

  20. Image registration of proximal femur with substantial bone changes: application in 3D visualization of bone loss of astronauts after long-duration spaceflight

    NASA Astrophysics Data System (ADS)

    Li, Wenjun; Sode, Miki; Saeed, Isra; Lang, Thomas

    2006-03-01

    We recently studied bone loss in crewmembers making 4 to 6 months flights on the International Space Station. We employed Quantitative Computed Tomography (QCT) technology (Lang et. al., J Bone Miner Res. 2004; v. 19, p. 1006), which made measurements of both cortical and trabecular bone loss that could not be obtained by using 2-dimensional dual x-ray absorptiometry (DXA) imaging technology. To further investigate the bone loss after spaceflight, we have developed image registration technologies to align serial scans so that bone changes can be directly visualized in a subregional level, which can provide more detailed information for understanding bone physiology during long-term spaceflight. To achieve effective and robust registration when large bone changes exist, we have developed technical adaptations to standard registration methods. Our automated image registration is mutual-information based. We have applied an automatically adaptive binning method in calculating the mutual information. After the pre- and post-flight scans are geometrically aligned, the interior bone changes can be clearly visualized. Image registration can also be applied to Finite Element Modeling (FEM) to compare bone strength change, where consistent loading conditions must be applied to serial scans.

  1. Association of Body Weight and Body Mass Index with Bone Mineral Density in Women and Men from Kosovo

    PubMed Central

    Rexhepi, Sylejman; Bahtiri, Elton; Rexhepi, Mjellma; Sahatciu-Meka, Vjollca; Rexhepi, Blerta

    2015-01-01

    Background and objective: Body weight and body mass index (BMI) are considered potentially modifiable determinants of bone mass. Therefore, the aim of this study was to explore the association between body weight and body mass index (BMI) with total hip and lumbar spine bone mineral density (BMD). Methods: This cross-sectional study included a population of 100 women and 32 men from Kosovo into three BMI groups. All the study subjects underwent dual-energy X-ray absorptiometry (DXA) measurements. Results: Total hip BMD levels of obese menopausal and premenopausal women and men were significantly higher compared to overweight or normal weight subjects, while lumbar spine BMD levels of only menopausal women and men were higher among obese subjects. Age-adjusted linear regression analysis showed that BMI is a significant independent associate of lumbar spine and total hip BMD in menopausal women and men. Conclusion: Despite positive association between BMI and lumbar spine and total hip BMD in menopausal women, presence of more obese and osteoporotic subjects among menopausal women represent a population at risk for fractures because of poor balance and frequent falls; therefore, both obesity and osteoporosis prevention efforts should begin early on in life. PMID:26543419

  2. Periprosthetic bone loss: diagnostic and therapeutic approaches

    PubMed Central

    Cavalli, Loredana; Brandi, Maria Luisa

    2014-01-01

    Total joint replacement surgery is being performed on an increasingly large part of the population. Clinical longevity of implants depends on their osseointegration, which is influenced by the load, the characteristics of the implant and the bone-implant interface, as well as by the quality and quantity of the surrounding bone. Aseptic loosening due to periprosthetic osteolysis is the most frequent known cause of implant failure. Wear of prosthetic materials results in the formation of numerous particles of debris that cause a complex biological response. Dual-energy X-ray Absorptiometry (DXA) is regarded as an accurate method to evaluate Bone Mineral Density (BMD) around hip or knee prostheses. Further data may be provided by a new device, the Bone Microarchitecture Analysis (BMA), which combines bone microarchitecture quantification and ultra high resolution osteo-articular imaging. Pharmacological strategies have been developed to prevent bone mass loss and to extend implant survival. Numerous trials with bisphosphonates show a protective effect on periprosthetic bone mass, up to 72 months after arthroplasty. Strontium ranelate has been demonstrated to increase the osseointegration of titanium implants in treated animals with improvement of bone microarchitecture and bone biomaterial properties. PMID:25642325

  3. Validation of bioelectrical impedance analysis (BIA) for estimation of body composition in Black, White and Hispanic adolescent girls.

    PubMed

    Going, S; Nichols, J; Loftin, M; Stewart, D; Lohman, T; Tuuri, G; Ring, K; Pickrel, J; Blew, R; J Stevens

    2006-01-01

    AIM: Equations for estimating % fat mass (%BF) and fat-free mass (FFM) from bioelectrical impedance analysis (BIA) that work in adolescent girls from different racial/ethnic backgrounds are not available. We investigated whether race/ethnicity influences estimation of body composition in adolescent girls. PRINCIPAL PROCEDURES: Prediction equations were developed for estimating FFM and %BF from BIA in 166 girls, 10-15 years old, consisting of 51 Black (B), 45 non-Black Hispanic (H), 55 non-Hispanic White (W) and 15 mixed (M) race/ethnicity girls, using dual energy x-ray absorptiometry (DXA) as the criterion method. FINDINGS: Black girls had similar %BF compared to other groups, yet were heavier per unit of height according to body mass index (BMI: kg.m(-2)) due to significantly greater FFM. BIA resistance index, age, weight and race/ethnicity were all significant predictors of FFM (R(2) = 0.92, SEE = 1.81 kg). Standardized regression coefficients showed resistance index (0.63) and weight (0.34) were the most important predictors of FFM. Errors in %BF (~2%) and FFM (~1.0 kg) were greater when race/ethnicity was not included in the equation, particularly in Black girls. We conclude the BIA-composition relationship in adolescent girls is influenced by race, and consequently have developed new BIA equations for adolescent girls for predicting FFM and %BF. PMID:17848976

  4. Dental panoramic image analysis for enhancement biomarker of mandibular condyle for osteoporosis early detection

    NASA Astrophysics Data System (ADS)

    Suprijanto; Azhari; Juliastuti, E.; Septyvergy, A.; Setyagar, N. P. P.

    2016-03-01

    Osteoporosis is a degenerative disease characterized by low Bone Mineral Density (BMD). Currently, a BMD level is determined by Dual Energy X-ray Absorptiometry (DXA) at the lumbar vertebrae and femur. Previous studies reported that dental panoramic radiography image has potential information for early osteoporosis detection. This work reported alternative scheme, that consists of the determination of the Region of Interest (ROI) the condyle mandibular in the image as biomarker and feature extraction from ROI and classification of bone conditions. The minimum value of intensity in the cavity area is used to compensate an offset on the ROI. For feature extraction, the fraction of intensity values in the ROI that represent high bone density and the ROI total area is perfomed. The classification will be evaluated from the ability of each feature and its combinations for the BMD detection in 2 classes (normal and abnormal), with the artificial neural network method. The evaluation system used 105 panoramic image data from menopause women which consist of 36 training data and 69 test data that were divided into 2 classes. The 2 classes of classification obtained 88.0% accuracy rate and 88.0% sensitivity rate.

  5. Inadequate Dietary Calcium and Vitamin D Intake in Patients with Osteoporotic Fracture

    PubMed Central

    Yoon, Dong Sik; Lee, Young-Kyun; Ha, Yong-Chan

    2016-01-01

    Background Inadequate calcium and vitamin D intake is a possible risk factor of osteoporosis. Our purposes were to estimate calcium and vitamin D intake in women with osteoporotic fractures, to determine associated factors for low calcium and vitamin D intake, and to evaluate the effects of calcium and vitamin D intake on bone mineral density (BMD). Methods This is a multicenter, hospital-based, and cross-sectional study involving 277 women with osteoporotic fractures. Dietary calcium and vitamin D intake were evaluated using the Korean Calcium Assessment Tool (KCAT) self-reported questionnaire. BMD was measured by dual energy X-ray absorptiometry (DXA) in the lumbar spine and femoral neck. Results Average daily calcium and vitamin D intake was 503.7±274.7 mg and 7.5±12.6 µg, respectively. Patients with low calcium intake had less family history of osteoporosis and were older. There was a negative correlation between age and calcium intake (r=-0.14; P=0.019). In multivariate analysis, calcium intake showed a positive correlation with BMD of femoral neck (β=0.0005, P=0.021). Conclusions About 80% of patients with osteoporotic fracture had calcium and vitamin D intake below the recommended dietary intake. Low calcium intake was associated with no family history of osteoporosis and older age. Dietary calcium intake showed positive effect on BMD. PMID:27294077

  6. Asymmetry in body composition in female hockey players.

    PubMed

    Krzykała, M; Leszczyński, P

    2015-08-01

    The aim of the study was to determine if a sport in which one side of the body is dominant, like field hockey, influences regional body composition and bone mineral density (BMD) distribution in particular body segments, and whether the sporting level is a determining factor. Dual energy X-ray absorptiometry (DXA) method (Lunar Prodigy Advance; General Electric, Madison, USA) with the whole body scan was used to measure bone mineral density, fat mass and lean mass in 31 female field hockey players divided according to their sporting level. The morphological asymmetry level was assessed between two body sides and body segments in athletes from the National Team (n=17) and from the Youth Team (n=14) separately and between groups. Bone mineral density in the lower extremity and of the trunk was significantly asymmetric in favor of the left side in the National Team. In the case of the Youth Team, only the trunk BMD indicated clear left-right difference with left side dominance. Both the lean mass and fat mass values were relatively higher on the left side of all body segments and it related to both analyzed groups of athletes. The present study shows that playing field hockey contributes to laterality in body composition and BMD and that the sporting level is a determining factor. In most cases the left side dominated. A greater asymmetry level was observed in more experienced female field hockey players. PMID:26077573

  7. Prevalence of asymptomatic urinary tract infections in morbidly obese dogs

    PubMed Central

    Witzel, Angela L.; Bartges, Joseph W.; Moyers, Tamberlyn S.; Kirk, Claudia A.

    2016-01-01

    Background. Obesity has reached epidemic proportions in dogs and, as in humans, cost of care has increased due to associated comorbidities. In humans, asymptomatic urinary tract infections (UTI) may be more prevalent in the obese. Asymptomatic bacteriuria (AB) is the term used when UTI are asymptomatic. We hypothesized that morbidly obese dogs are similarly more likely to have asymptomatic bacteriuria than lean, overweight, and moderately obese dogs. Methods. A retrospective study was undertaken to explore a possible association between obesity and asymptomatic bacteriuria. Records from lean, overweight, and obese dogs receiving both a dual energy absorptiometry (DXA) scan and urine culture were included. Results. Six positive urine cultures were identified among 46 dogs fulfilling search criteria. All six positive cultures were found in dogs with body fat percentage of >45%. In dogs with body fat percentage of <45%, there were no positive urine cultures. Discussion. There was an increased prevalence of asymptomatic bacteriuria in the morbidly obese dogs in this study compared to those that were lean, overweight, or moderately obese. Whether antibiotic therapy is necessary in such cases is still being debated, but because asymptomatic bacteriuria may be associated with ascending infections, uroliths, or other complications, the data reported herein support the screening of obese patients for bacteriuria. PMID:26989606

  8. Disordered-Eating Attitudes in Relation to Bone Mineral Density and Markers of Bone Turnover in Overweight Adolescents

    PubMed Central

    Schvey, Natasha A.; Tanofsky-Kraff, Marian; Yanoff, Lisa B.; Checchi, Jenna M.; Shomaker, Lauren B.; Brady, Sheila; Savastano, David M.; Ranzenhofer, Lisa M.; Yanovski, Susan Z.; Reynolds, James C.; Yanovski, Jack A.

    2009-01-01

    Purpose To examine the relationships between cognitive eating restraint and both bone mineral density (BMD) and markers of bone turnover in overweight adolescents. Methods 137 overweight (BMI 39.1±6.8 kg/m2) African American and Caucasian adolescent (age=14.4 ± 1.4y) girls (66.4%) and boys were administered the Eating Disorder Examination (EDE) interview and Eating Inventory (EI) questionnaire and underwent dual energy x-ray absorptiometry (DXA) to measure total lumbar spine BMD. Markers of bone formation (serum bone specific alkaline phosphatase and osteocalcin), bone resorption (24-hour urine N-telopeptides), and stress (urine free cortisol) were measured. Results After accounting for the contribution of demographics, height, weight, serum 25-hydroxyvitamin D, and depressive symptoms, adolescents’ weight concern, as assessed by interview, was a significant contributor to a model of urine free cortisol (β =.30, p <.05). Shape concern, as also assessed by interview, was significantly associated with lumbar spine bone mineral density (β =.−.15, p < 05). Dietary restraint was not a significant predictor in any of these models. Conclusions These findings suggest that among severely overweight adolescents, dissatisfaction with shape and weight may be salient stressors. Future research is required to illuminate the relationship between bone health and disordered-eating attitudes in overweight adolescents. PMID:19541247

  9. Changes in liraglutide-induced body composition are related to modifications in plasma cardiac natriuretic peptides levels in obese type 2 diabetic patients

    PubMed Central

    2014-01-01

    Background and aims Liraglutide treatment can improve glycemic control with a concomitant weight loss, but the underlying mechanism on weight loss is not completely understood. Cardiac natriuretic peptides (NPs) can resist body fat accumulation through increasing adipocytes lypolysis. In this study, we tested the hypothesis that liraglutide-induced weight loss was associated with increased plasma NPs concentrations. Methods Thirty-one outpatients with type 2 diabetes (T2D) treated with metformin and other oral antidiabetic drugs except for thiazolidinediones (TZDs) were subcutaneously administered with liraglutide for 12 weeks. Body composition, abdominal visceral adipose tissue areas (VAT) and subcutaneous adipose tissue areas (SAT) were assessed at pre- and post-treatment by dual-energy X-ray absorptiometry (DXA) scanning and abdominal computerized tomography (CT). Plasma atrial natriuretic peptides (ANP) and B-type ventricular natriuretic peptides (BNP) concentrations were tested by commercial ELISA Kit quantitatively. Results Following 12-week liraglutide treatment, body weight, waist circumference, total fat and lean mass, fat percentage, SAT and VAT areas were significantly reduced from baseline. Concurrently, plasma ANP and BNP levels were significantly increased following 12-week liraglutide treatment. There were significant correlations between the reductions in body compositions and the increases in both plasma ANP and BNP levels. Conclusions There were significant correlations between increases in both plasma ANP and BNP levels and changes in liraglutide-induced body composition. Our data implied that increases in plasma NPs may add a novel dimension to explain how liraglutide induces weight loss. PMID:24498905

  10. Physical Characteristics Associated with Weight Misperception among Overweight and Obese Men: NHANES 1999-2006

    PubMed Central

    Lewis, Dwight W.; Dutton, Gareth R.; Affuso, Olivia

    2014-01-01

    Objective The purpose of this study was to 1) determine the prevalence of weight misperception among overweight and obese men with total body fat levels ≥ 25%; and 2) examine associations of weight misperception with anthropometric and body composition measures. Methods Data came from 4,200 overweight or obese men from the 1999-2006 National Health and Nutrition Examination Surveys. Weight misperception was operationalized as having a dual energy x-ray absorptiometry (DXA) derived total body fat percent (TBF) ≥ 25% and classifying oneself as either “underweight” or “about right weight.” Logistic regression was used to determine physical characteristics associated with weight misperception. Results Weight misperception was highest among Mexican American (35.9%) followed by Black (30.8%) and White men (22.9%). Physical characteristics (OR, 95% CI) associated with weight misperception were decreased arm fat (0.95, 0.91-0.98), being overweight (9.02, 5.34-15.24), and having a waist circumference ≤ 94 cm (2.31, 1.72-3.09). Conclusions Findings suggest that future research should include a measure of adiposity in the operationalization of weight misperception among male populations. PMID:25354815

  11. Relationships between body roundness with body fat and visceral adipose tissue emerging from a new geometrical model

    PubMed Central

    Thomas, Diana M.; Bredlau, Carl; Bosy-Westphal, Anja; Mueller, Manfred; Shen, Wei; Gallagher, Dympna; Maeda, Yuna; McDougall, Andrew; Peterson, Courtney M.; Ravussin, Eric; Heymsfield, Steven B.

    2013-01-01

    Objective To develop a new geometrical index that combines height, waist circumference (WC), and hip circumference (HC) and relate this index to total and visceral body fat. Design and Methods Subject data were pooled from three databases that contained demographic, anthropometric, dual energy X-ray absorptiometry (DXA) measured fat mass, and magnetic resonance imaging measured visceral adipose tissue (VAT) volume. Two elliptical models of the human body were developed. Body roundness was calculated from the model using a well-established constant arising from the theory. Regression models based on eccentricity and other variables were used to predict % body fat and % VAT. Results A body roundness index (BRI) was derived to quantify the individual body shape in a height-independent manner. Body roundness slightly improved predictions of % body fat and % VAT compared to the traditional metrics of body mass index (BMI), WC, or HC. On this basis, healthy body roundness ranges were established. An automated graphical program simulating study results was placed at http://www.pbrc.edu/bodyroundness. Conclusions Body roundness index, a new shape measure, is a predictor of % body fat and % VAT and can be applied as a visual tool for health status evaluations. PMID:23519954

  12. Lower limbs composition and radiographic knee osteoarthritis (RKOA) in Chingford sample--a longitudinal study.

    PubMed

    Blumenfeld, Orit; Williams, Frances M K; Hart, Deborah J; Arden, Nigel K; Spector, Timothy D; Livshits, Gregory

    2013-01-01

    Our aim in this longitudinal study was to evaluate to what extent fat and lean tissue mass variations are associated and can predict RKOA in a large sample of British women followed-up over 10 years. Kellgren/Lawrence (K/L), joint space narrowing (JSN) and osteophyte (OSP) grades were scored from radiographs of both knees in 909 middle-aged women from the Chingford registry. Body composition components were assessed using the dual energy X-ray absorptiometry (DXA) method. In cross-sectional analysis, combined effect of age, BMI and leg tissue composition was required for best fitting model explaining variations of K/L scoring and osteophytes at lateral compartment. To explain medial osteophytes, age and BMI were sufficient to generate the best fitting model. In prediction analysis, leg lean mass was the more powerful predictor of K/L, medial osteophytes than BMI. In conclusion, BMI appears to influence the development of knee OA through both fat and/or lean mass, depending on RKOA phenotype. PMID:23084478

  13. The Relationship between H. pylori Infection and Osteoporosis in Japan

    PubMed Central

    Asaoka, Daisuke; Nagahara, Akihito; Hojo, Mariko; Sasaki, Hitoshi; Shimada, Yuji; Yoshizawa, Takashi; Osada, Taro; Watanabe, Sumio

    2014-01-01

    Background and Objective. H. pylori infection causes a chronic inflammation in the gastric mucosa. However, this local inflammation may result in extra-digestive conditions. Our aim is to investigate the relationship between H. pylori infection and osteoporosis in Japan. Methods. This cross-sectional study was conducted among outpatients at the Juntendo University Hospital between 2008 and 2014. Participants for patient profile, H. pylori infection status, comorbidity, internal medical therapies, lumbar dual-energy X-ray absorptiometry (DXA), and bone turnover marker were collected and upper gastrointestinal endoscopy for reflux esophagitis, hiatal hernia, peptic ulcer disease (PUD), and endoscopic gastric mucosal atrophy (EGA) was performed. The diagnosis of osteoporosis was performed in accordance with the Japanese criteria. We investigated risk factors of osteoporosis. Results. Of the eligible 200 study subjects, 41 cases were of osteoporosis. Bivariate analysis showed that age, being female, BMI, alcohol, smoking, H. pylori, bone-specific ALP, PUD, and EGA were related to osteoporosis. Multivariate analysis showed that age (OR 1.13; 95%CI 1.07–1.20), being female (OR 4.77; 95%CI 1.78–12.77), BMI (OR 0.79; 95%CI 0.68–0.92), H. pylori (OR 5.33; 95%CI 1.73–16.42), and PUD (OR 4.98; 95%CI 1.51–16.45) were related to osteoporosis. Conclusions. H. pylori infection may be a risk factor of osteoporosis in Japan. PMID:25024699

  14. Effect of hormone therapy on lean body mass, falls, and fractures: Six-year results from the Women’s Health Initiative Hormone Trials

    PubMed Central

    Bea, Jennifer W.; Zhao, Qiuhong; Cauley, Jane A.; LaCroix, Andrea Z.; Bassford, Tamsen; Lewis, Cora E.; Jackson, Rebecca D.; Tylavsky, Frances A.; Chen, Zhao

    2010-01-01

    Objective Loss of lean body mass with aging may contribute to falls and fractures. The objective of this analysis was to determine if taking postmenopausal hormone therapy (HT: estrogen plus progestogen therapy, EPT or estrogen therapy alone, ET) favorably affects age-related changes in lean body mass and if these changes partially account for decreased falls or fractures with HT. Methods Participants randomly assigned to either EPT (n=543) or control (n=471) and ET (n= 453) or control (n= 474) and receiving dual-energy X-ray absorptiometry (DXA) scans to estimate body composition during the Women’s Health Initiative (WHI) were evaluated. Falls and fracture occurrence were obtained by annual self-report. Fractures were confirmed by clinical chart review. Results At 6yrs post-randomization, lean body mass was not different between HT and control groups. Although lean body mass positively influenced BMD, independent of HT status, the preserved lean body mass observed in the HT arms in the first 3 years did not significantly contribute to models evaluating HT influence on falls and fractures between years 3 and 6. Women taking at least 80% of their medication in the HT arms demonstrated fewer falls compared to placebo; this difference was not attributable to change in lean body mass. Conclusions Despite early preservation of lean body mass with HT (3years), HT did not ameliorate long-term (6 years) loss in lean body mass with aging. PMID:20689466

  15. Home-Schooled Children are thinner, leaner, and report better diets relative to traditionally-schooled children

    PubMed Central

    Cardel, Michelle; Willig, Amanda L.; Dulin-Keita, Akilah; Casazza, Krista; Cherrington, Andrea; Gunnarsdottir, Thrudur; Johnson, Susan L.; Peters, John C.; Hill, James O.; Allison, David B.; Fernández, José R.

    2013-01-01

    Objective To examine and compare the relationships among diet, physical activity, and adiposity between home-schooled children (HSC) and traditionally-schooled children (TSC). Design and Methods Subjects were HSC (n=47) and TSC (n=48) aged 7 to 12 years old. Dietary intakes were determined via two 24-hour recalls and physical activity was assessed with 7 days of accelerometry. Fat mass (FM), trunk fat, and percent body fat (%BF) were measured by dual-energy x-ray absorptiometry (DXA). Results Relative to HSC, TSC demonstrated significantly higher BMI percentiles, FM, trunk fat, and %BF; consumed 120 total kilocalories more per day; and reported increased intakes of trans fats, total sugar, added sugars, calcium, and lower intakes of fiber, fruits, and vegetables (p<0.05). At lunch, TSC consumed significantly more calories, sugar, sodium, potassium, and calcium compared to HSC (p<0.05). Physical activity did not differ between groups. Traditional schooling was associated with increased consumption of trans fat, sugar, calcium (p<.05); lower intakes of fiber, and fruits and vegetables (p<.05); and higher FM, %BF, and trunk fat (p<0.01), after adjustment for covariates. Conclusions These data suggest HSC may consume diets that differ in energy and nutrient density relative to TSC, potentially contributing to differences in weight and adiposity. PMID:24039204

  16. Quantitative Magnetic Resonance Fat Measurements in Humans correlate With Established Methods but Are Biased

    PubMed Central

    Gallagher, Dympna; Thornton, John C.; He, Qing; Wang, Jack; Yu, Wen; Bradstreet, Thomas E.; Burke, Joanne; Heymsfield, Steven B.; Rivas, Veronica M.; Kaufman, Rhonda

    2012-01-01

    Precision and accuracy of the quantitative magnetic resonance (QMR) system for measuring fat in phantoms and total body fat (TBF) in humans were investigated. Measurements were made using phantoms: oil, beef with water, beef with oil, and humans with oil and water. TBFQMR in humans was compared with TBF by a four-compartment model (TBF4C). The coefficient of variation (CV) for replicate TBFQMR was 0.437%. QMR fat was lower at 23 °C vs. 37 °C. The fat increase in QMR phantom studies was consistent with the oil increase. When oil was added with humans, the increase in TBFQMR was >250 g for the initial 250 g of oil. With additional oil increments, the increase in TBFQMR was consistent with the amount of oil added. When water was added with humans, the TBFQMR increased independent of the amount of water added. TBFQMR was significantly less (mean ± s.e.) than TBF4C (females: −0.68 ± 0.27 kg, males: −4.66 ± 0.62 kg; P = 0.0001), TBFBV (females: −1.90 ± 0.40 kg; males: −5.68 ± 0.75 kg; P = 0.0001), and TBFD2O for males, but greater for females (1.19 ± 0.43 kg vs. −3.69 ± 0.81 kg for males; P = 0.0003). TBFQMR was lower than TBFiDXA with the difference greater in males (P = 0.001) and decreased with age (P = 0.011). The strong linear relationships between TBFQMR and TBF4C, TBFBV, and TBFD2O with slopes consistent with unity suggest that modifications are required to improve the accuracy. Should the latter be accomplished, QMR holds promise as a highly precise, rapid, and safe, noninvasive method for estimating the amount of and changes in TBF in overweight and severely obese persons. PMID:20448539

  17. Newton's method

    SciTech Connect

    More, J. J.; Sorensen, D. C.

    1982-02-01

    Newton's method plays a central role in the development of numerical techniques for optimization. In fact, most of the current practical methods for optimization can be viewed as variations on Newton's method. It is therefore important to understand Newton's method as an algorithm in its own right and as a key introduction to the most recent ideas in this area. One of the aims of this expository paper is to present and analyze two main approaches to Newton's method for unconstrained minimization: the line search approach and the trust region approach. The other aim is to present some of the recent developments in the optimization field which are related to Newton's method. In particular, we explore several variations on Newton's method which are appropriate for large scale problems, and we also show how quasi-Newton methods can be derived quite naturally from Newton's method.

  18. Sonofluorescence method

    NASA Astrophysics Data System (ADS)

    Li, Huamao

    1998-11-01

    In this paper, a new sonofluorescence method is proposed. Based upon the method, the author has obtained the sonofluorescence emission spectrum of an aqueous luminol- NaOH solution, and displayed the cavitation field distribution in a sonochemical glass reactor.

  19. Usefulness of bone density measurement in fallers.

    PubMed

    Blain, Hubert; Rolland, Yves; Beauchet, Olivier; Annweiler, Cedric; Benhamou, Claude-Laurent; Benetos, Athanase; Berrut, Gilles; Audran, Maurice; Bendavid, Sauveur; Bousson, Valérie; Briot, Karine; Brazier, Michel; Breuil, Véronique; Chapuis, Laure; Chapurlat, Roland; Cohen-Solal, Martine; Cortet, Bernard; Dargent, Patricia; Fardellone, Patrice; Feron, Jean-Marc; Gauvain, Jean-Bernard; Guggenbuhl, Pascal; Hanon, Olivier; Laroche, Michel; Kolta, Sami; Lespessailles, Eric; Letombe, Brigitte; Mallet, Eric; Marcelli, Christian; Orcel, Philippe; Puisieux, François; Seret, Patrick; Souberbielle, Jean-Claude; Sutter, Bruno; Trémollières, Florence; Weryha, Georges; Roux, Christian; Thomas, Thierry

    2014-10-01

    The objective of this systematic literature review is to discuss the latest French recommendation issued in 2012 that a fall within the past year should lead to bone mineral density (BMD) measurement using dual-energy X-ray absorptiometry (DXA). This recommendation rests on four facts. First, osteoporosis and fall risk are the two leading risk factors for nonvertebral fractures in postmenopausal women. Second, BMD measurement using DXA supplies significant information on the fracture risk independently from the fall risk. Thus, when a fall occurs, the fracture risk increases as BMD decreases. Third, osteoporosis drugs have been proven effective in preventing fractures only in populations with osteoporosis defined based on BMD criteria. Finally, the prevalence of osteoporosis is high in patients who fall and increases in the presence of markers for frailty (e.g., recurrent falls, sarcopenia [low muscle mass and strength], limited mobility, and weight loss), which are risk factors for both osteoporosis and falls. Nevertheless, life expectancy should be taken into account when assessing the appropriateness of DXA in fallers, as osteoporosis treatments require at least 12months to decrease the fracture risk. Another relevant factor is the availability of DXA, which may be limited due to geographic factors, patient dependency, or severe cognitive impairments, for instance. Studies are needed to better determine how the fall risk and frailty should be incorporated into the fracture risk evaluation based on BMD and the FRAX® tool. PMID:24703626

  20. Validity of deuterium oxide dilution for the measurement of body fat among Singaporeans.

    PubMed

    Deurenberg-Yap, Mabel; Deurenberg, Paul

    2002-09-01

    Body fat percent (BF%) was measured in 108 adult Chinese, 76 Malays, and 107 Indians in Singapore by densitometry, deuterium oxide dilution (hydrometry), dual energy x-ray absorptiometry (DXA) and a chemical four-compartment model (BF%4c). The hydration of the fat-free mass (FFM) was calculated. Subjects ranged in age from 18 to 69 years and their body mass index ranged from 16 to 40 kg/m2. BF%4c for the various subgroups were: Chinese females (33.5 +/- 7.5%), Chinese males (24.4 +/- 6.1%), Malay females (37.8 +/- 6.3%), Malay males (26.0 +/- 7.6%), Indian females (38.2 +/- 7.0%) and Indian males (28.1 +/- 5.5%). Biases were found between BF%4c and BF% measured by 2-compartment models (hydrometry, densitometry, DXA), with systematic underestimation by DXA and densitometry. On a group level hydrometry had the lowest bias while DXA gave the highest bias. When validated against BF%4c, 2-compartment models were found to be unsuitable for accurate measures of body fat due to high biases at the individual level and the violation of assumptions of constant hydration of FFM and density FFM among the ethnic groups. On a group level the best 2-compartment model for measuring body fat was found to be hydrometry. PMID:12362808

  1. Bone and Celiac Disease.

    PubMed

    Zanchetta, María Belén; Longobardi, Vanesa; Bai, Julio César

    2016-04-01

    More than 50 % of untreated patients with celiac disease (CD) have bone loss detected by bone densitometry (dual-energy X-ray absorptiometry:DXA). Moreover, patients with CD are more likely to have osteoporosis and fragility fractures, especially of the distal radius. Although still controversial, we recommend DXA screening in all celiac disease patients, particularly in those with symptomatic CD at diagnosis and in those who present risk factors for fracture such as older age, menopausal status, previous fracture history, and familial hip fracture history. Bone microarchitecture, especially the trabecular network, may be deteriorated, explaining the higher fracture risk in these patients. Adequate calcium and vitamin D supplementation are also recommended to optimize bone recovery, especially during the first years of gluten free diet (GFD). If higher fracture risk persists after 1 or 2 years of GFD, specific osteoactive treatment may be necessary to improve bone health. PMID:26875096

  2. RESISTIVITY METHODS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Resistivity methods were among the first geophysical techniques developed. The basic concept originated with Conrad Schlumberger, who conducted the initial resistivity field tests in Normandy, France during 1912. The resistivity method, employed in its earliest and most conventional form, uses an ex...

  3. Electrodeionization method

    DOEpatents

    Lin, YuPo J.; Hestekin, Jamie; Arora, Michelle; St. Martin, Edward J.

    2004-09-28

    An electrodeionization method for continuously producing and or separating and/or concentrating ionizable organics present in dilute concentrations in an ionic solution while controlling the pH to within one to one-half pH unit method for continuously producing and or separating and/or concentrating ionizable organics present in dilute concentrations in an ionic solution while controlling the pH to within one to one-half pH unit.

  4. How prevalent and costly are Choosing Wisely low-value services? Evidence from Medicare beneficiaries.

    PubMed

    Collado, Megan

    2014-10-01

    (1) Through the Choosing Wisely initiative, medical specialty societies identified non-indicated cardiac testing in low-risk patients and short-interval dual-energy X-ray absorptiometry (DXA) or bone density testing as low-value care. (2) Nationally, 13 percent of low-risk Medicare beneficiaries received non-indicated cardiac tests, and 10 percent of DXAs reimbursed by Medicare were administered at inappropriately short intervals. There is significant geographic variation in the provision of these services. (2) Carefully designed policy and payment changes will likely prove most effective in reducing low-value care. PMID:25330546

  5. Postmenopausal bone loss and the risk of osteoporosis.

    PubMed

    Christiansen, C

    1994-01-01

    The two most important risk factors for long-term skeletal health are the peak bone mass and the subsequent rate of bone loss. The rate of bone loss after skeletal maturity is determined by both genetic factors and environmental factors. Furthermore, all factors that impair estrogen production will increase bone loss. The present risk of developing osteoporosis and fractures may be assessed by bone mass measurements in the total skeleton, or in local parts of the skeleton such as the spine, hip and forearm, by single-photon/X-ray absorptiometry (SPA or SXA), dual-photon/energy X-ray absorptiometry (DPA or DXA), or quantitative computed tomography (QCT). Furthermore, the rate of bone loss in postmenopausal women may be assessed by means of a number of biochemical markers. The fútúre risk of developing osteoporosis may thus be determined by combining the values for bone mineral content and bone loss. PMID:8081059

  6. Ensemble Methods

    NASA Astrophysics Data System (ADS)

    Re, Matteo; Valentini, Giorgio

    2012-03-01

    Ensemble methods are statistical and computational learning procedures reminiscent of the human social learning behavior of seeking several opinions before making any crucial decision. The idea of combining the opinions of different "experts" to obtain an overall “ensemble” decision is rooted in our culture at least from the classical age of ancient Greece, and it has been formalized during the Enlightenment with the Condorcet Jury Theorem[45]), which proved that the judgment of a committee is superior to those of individuals, provided the individuals have reasonable competence. Ensembles are sets of learning machines that combine in some way their decisions, or their learning algorithms, or different views of data, or other specific characteristics to obtain more reliable and more accurate predictions in supervised and unsupervised learning problems [48,116]. A simple example is represented by the majority vote ensemble, by which the decisions of different learning machines are combined, and the class that receives the majority of “votes” (i.e., the class predicted by the majority of the learning machines) is the class predicted by the overall ensemble [158]. In the literature, a plethora of terms other than ensembles has been used, such as fusion, combination, aggregation, and committee, to indicate sets of learning machines that work together to solve a machine learning problem [19,40,56,66,99,108,123], but in this chapter we maintain the term ensemble in its widest meaning, in order to include the whole range of combination methods. Nowadays, ensemble methods represent one of the main current research lines in machine learning [48,116], and the interest of the research community on ensemble methods is witnessed by conferences and workshops specifically devoted to ensembles, first of all the multiple classifier systems (MCS) conference organized by Roli, Kittler, Windeatt, and other researchers of this area [14,62,85,149,173]. Several theories have been

  7. Ensemble Methods

    NASA Astrophysics Data System (ADS)

    Re, Matteo; Valentini, Giorgio

    2012-03-01

    Ensemble methods are statistical and computational learning procedures reminiscent of the human social learning behavior of seeking several opinions before making any crucial decision. The idea of combining the opinions of different "experts" to obtain an overall “ensemble” decision is rooted in our culture at least from the classical age of ancient Greece, and it has been formalized during the Enlightenment with the Condorcet Jury Theorem[45]), which proved that the judgment of a committee is superior to those of individuals, provided the individuals have reasonable competence. Ensembles are sets of learning machines that combine in some way their decisions, or their learning algorithms, or different views of data, or other specific characteristics to obtain more reliable and more accurate predictions in supervised and unsupervised learning problems [48,116]. A simple example is represented by the majority vote ensemble, by which the decisions of different learning machines are combined, and the class that receives the majority of “votes” (i.e., the class predicted by the majority of the learning machines) is the class predicted by the overall ensemble [158]. In the literature, a plethora of terms other than ensembles has been used, such as fusion, combination, aggregation, and committee, to indicate sets of learning machines that work together to solve a machine learning problem [19,40,56,66,99,108,123], but in this chapter we maintain the term ensemble in its widest meaning, in order to include the whole range of combination methods. Nowadays, ensemble methods represent one of the main current research lines in machine learning [48,116], and the interest of the research community on ensemble methods is witnessed by conferences and workshops specifically devoted to ensembles, first of all the multiple classifier systems (MCS) conference organized by Roli, Kittler, Windeatt, and other researchers of this area [14,62,85,149,173]. Several theories have been

  8. Characterization methods

    SciTech Connect

    Glass, J.T.

    1993-01-01

    Methods discussed in this compilation of notes and diagrams are Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, and other surface analysis techniques (auger electron spectroscopy, x-ray photoelectron spectroscopy, electron energy loss spectroscopy, and scanning tunnelling microscopy). A comparative evaluation of different techniques is performed. In-vacuo and in-situ analyses are described.

  9. Drilling method

    SciTech Connect

    Stokley, C.O.; Haas, R.C.

    1991-04-30

    This patent describes a drilling method. It includes: rotating a drill bit in a well head to drill a well in an earth formation while circulating drilling fluid consisting essentially of a liquid; conducting the returning drilling fluid, and oil and gas from the formation to a flow rate control valve and to a pressure control valve; and conducting fluid from the flow rate control valve and the pressure control valve to a separator vessel maintained under pressure.

  10. SINTERING METHOD

    DOEpatents

    Googin, J.M.

    1963-11-01

    Methods of making articles by powder metallurgy techniques are presented. An article is made by packing a metal powder into a desired shape, raising the temperature of the powder compact to a sintering temperature in the presence of a reducing gas, and alternately increasing and decreasing the pressure of the gas while the temperatume is being raised. The product has a greater density than can be achieved by sintering for the same length of time at a constant gas pressure. (AEC)

  11. COATING METHOD

    DOEpatents

    Townsend, R.G.

    1959-08-25

    A method is described for protectively coating beryllium metal by etching the metal in an acid bath, immersing the etched beryllium in a solution of sodium zincate for a brief period of time, immersing the beryllium in concentrated nitric acid, immersing the beryhlium in a second solution of sodium zincate, electroplating a thin layer of copper over the beryllium, and finally electroplating a layer of chromium over the copper layer.

  12. Genotyping methods.

    PubMed

    Tümmler, Burkhard

    2014-01-01

    Genotyping allows for the identification of bacterial isolates to the strain level and provides basic information about the evolutionary biology, population biology, taxonomy, ecology, and genetics of bacteria. Depending on the underlying question and available resources, Pseudomonas aeruginosa strains may be typed by anonymous fingerprinting techniques or electronically portable sequence-based typing methods such as multiple locus variable number tandem repeat (VNTR) analysis (MLVA), multilocus sequence typing, or oligonucleotide microarray. Macrorestriction fragment pattern analysis is a genotyping method that is globally applicable to all bacteria and hence has been and still is the reference method for strain typing in bacteriology. Agarose-embedded chromosomal DNA is cleaved with a rare-cutting restriction endonuclease and the generated 20-70 fragments are then separated by pulsed-field gel electrophoresis. The chapter provides a detailed step-by-step manual for SpeI genome fingerprinting of Pseudomonas chromosomes that has been optimized for SpeI fragment pattern analysis of P. aeruginosa. PMID:24818895

  13. Prediction Equation for Lower Limbs Lean Soft Tissue in Circumpubertal Boys Using Anthropometry and Biological Maturation

    PubMed Central

    Valente-dos-Santos, João; Coelho-e-Silva, Manuel J.; Machado-Rodrigues, Aristides M.; Elferink-Gemser, Marije T.; Malina, Robert M.; Petroski, Édio L.; Minderico, Cláudia S.; Silva, Analiza M.; Baptista, Fátima; Sardinha, Luís B.

    2014-01-01

    Lean soft tissue (LST), a surrogate of skeletal muscle mass, is largely limited to appendicular body regions. Simple and accurate methods to estimate lower limbs LST are often used in attempts to partition out the influence of body size on performance outputs. The aim of the current study was to develop and cross-validate a new model to predict lower limbs LST in boys aged 10–13 years, using dual-energy X-ray absorptiometry (DXA) as the reference method. Total body and segmental (lower limbs) composition were assessed with a Hologic Explorer-W QDR DXA scanner in a cross-sectional sample of 75 Portuguese boys (144.8±6.4 cm; 40.2±9.0 kg). Skinfolds were measured at the anterior and posterior mid-thigh, and medial calf. Circumferences were measured at the proximal, mid and distal thigh. Leg length was estimated as stature minus sitting height. Current stature expressed as a percentage of attained predicted mature stature (PMS) was used as an estimate of biological maturity status. Backward proportional allometric models were used to identify the model with the best statistical fit: ln (lower limbs LST)  = 0.838× ln (body mass) +0.476× ln (leg length) – 0.135× ln (mid-thigh circumference) – 0.053× ln (anterior mid-thigh skinfold) – 0.098× ln (medial calf skinfold) – 2.680+0.010× (percentage of attained PMS) (R = 0.95). The obtained equation was cross-validated using the predicted residuals sum of squares statistics (PRESS) method (R2PRESS = 0.90). Deming repression analysis between predicted and current lower limbs LST showed a standard error of estimation of 0.52 kg (95% limits of agreement: 0.77 to −1.27 kg). The new model accurately predicts lower limbs LST in circumpubertal boys. PMID:25229472

  14. Gelcasting methods

    DOEpatents

    Walls, Claudia A.; Kirby, Glen H.; Janney, Mark A.; Omatete, Ogbemi O.; Nunn, Stephen D.; McMillan, April D.

    2000-01-01

    A method of gelcasting includes the steps of providing a solution of at least hydroxymethylacrylamide (HMAM) and water. At least one inorganic powder is added to the mixture. At least one initiator system is provided to polymerize the HMAM. The initiator polymerizes the HMAM and water, to form a firm hydrogel that contains the inorganic powder. One or more comonomers can be polymerized with the HMAM monomer, to alter the final properties of the gelcast material. Additionally, one or more additives can be included in the polymerization mixture, to alter the properties of the gelcast material.

  15. QSAR Methods.

    PubMed

    Gini, Giuseppina

    2016-01-01

    In this chapter, we introduce the basis of computational chemistry and discuss how computational methods have been extended to some biological properties and toxicology, in particular. Since about 20 years, chemical experimentation is more and more replaced by modeling and virtual experimentation, using a large core of mathematics, chemistry, physics, and algorithms. Then we see how animal experiments, aimed at providing a standardized result about a biological property, can be mimicked by new in silico methods. Our emphasis here is on toxicology and on predicting properties through chemical structures. Two main streams of such models are available: models that consider the whole molecular structure to predict a value, namely QSAR (Quantitative Structure Activity Relationships), and models that find relevant substructures to predict a class, namely SAR. The term in silico discovery is applied to chemical design, to computational toxicology, and to drug discovery. We discuss how the experimental practice in biological science is moving more and more toward modeling and simulation. Such virtual experiments confirm hypotheses, provide data for regulation, and help in designing new chemicals. PMID:27311459

  16. Measurements in Mandibular Pantomographic X-rays and Relation to Skeletal Mineral Densitometric Values.

    PubMed

    Singh, Saumyendra V; Aggarwal, Himanshi; Gupta, Vaibhav; Kumar, Pradeep; Tripathi, Arvind

    2016-01-01

    The gold standard diagnostic modality for osteoporosis is dual-energy X-ray absorptiometry (DXA). But it is expensive and often unavailable. Studies have demonstrated that decreased bone mineral density (BMD) may affect mandibular bone morphometrically on radiographs. Such studies are rare in the Indian population. This study was conducted to evaluate correlation between radiomorphometric markers on digital orthopantomograms (OPGs) and BMD measurements done by DXA in an Indian population. A total of 344 subjects aged 45 years or above, who visited a dental outpatient department over a period of 6 years were included in the study after obtaining ethical committee approval and informed consent. Digital OPG and DXA BMD measurements were obtained. Subjects' T-scores were obtained, on the basis of which they were divided into osteoporotic, osteopenic, and normal. OPGs were evaluated to obtain the mandibular cortical index (MCI) and the panoramic mandibular index (PMI). Correlations of MCI and PMI with BMD were analyzed statistically with SPSS (version 16.0; SPSS, Chicago, IL). In the osteoporotic group, there was no subject with MCI finding of C1, and 77.42% prevalence of C3 finding was found. C2 finding was in highest proportion in the osteopenic group (p<0.05). Normal BMD group was associated with the C1 finding of 76.47%. Almost 48% of the osteoporotic group had a PMI score of <0.40, whereas 50% of osteopenic subjects had a PMI score of 0.4-0.44. Normal subjects having a PMI score of >0.44 constituted 49.1% of the population. Mean BMD scores decreased significantly with increasing MCI stage and increased significantly with increasing PMI (p<0.05). Significant correlations between PMI and MCI were obtained with DXA BMD. Digital OPGs may provide an economical and reliable diagnostic tool to rule out osteoporosis or osteopenia in undiagnosed patients, where DXA screening may not be available or is financially nonviable. PMID:25934028

  17. Tensiometer methods

    DOEpatents

    Grover, Blair K.; Hubbell, Joel M.; Sisson, James B.; Casper, William L.

    2005-12-20

    A method for collecting data regarding a matric potential of a media includes providing a tensiometer having a stainless steel tensiometer casing, the stainless steel tensiometer casing comprising a tip portion which includes a wetted porous stainless steel membrane through which a matric potential of a media is sensed; driving the tensiometer into the media using an insertion tube comprising a plurality of probe casing which are selectively coupled to form the insertion tube as the tensiometer is progressively driven deeper into the media, wherein the wetted porous stainless steel membrane is in contact with the media; and sensing the matric potential the media exerts on the wetted porous stainless steel membrane by a pressure sensor in fluid hydraulic connection with the porous stainless steel membrane. A tensiometer includes a stainless steel casing.

  18. Casting methods

    DOEpatents

    Marsden, Kenneth C.; Meyer, Mitchell K.; Grover, Blair K.; Fielding, Randall S.; Wolfensberger, Billy W.

    2012-12-18

    A casting device includes a covered crucible having a top opening and a bottom orifice, a lid covering the top opening, a stopper rod sealing the bottom orifice, and a reusable mold having at least one chamber, a top end of the chamber being open to and positioned below the bottom orifice and a vacuum tap into the chamber being below the top end of the chamber. A casting method includes charging a crucible with a solid material and covering the crucible, heating the crucible, melting the material, evacuating a chamber of a mold to less than 1 atm absolute through a vacuum tap into the chamber, draining the melted material into the evacuated chamber, solidifying the material in the chamber, and removing the solidified material from the chamber without damaging the chamber.

  19. WELDING METHOD

    DOEpatents

    Cornell, A.A.; Dunbar, J.V.; Ruffner, J.H.

    1959-09-29

    A semi-automatic method is described for the weld joining of pipes and fittings which utilizes the inert gasshielded consumable electrode electric arc welding technique, comprising laying down the root pass at a first peripheral velocity and thereafter laying down the filler passes over the root pass necessary to complete the weld by revolving the pipes and fittings at a second peripheral velocity different from the first peripheral velocity, maintaining the welding head in a fixed position as to the specific direction of revolution, while the longitudinal axis of the welding head is disposed angularly in the direction of revolution at amounts between twenty minutas and about four degrees from the first position.

  20. Correlation between Parameters of Calcaneal Quantitative Ultrasound and Hip Structural Analysis in Osteoporotic Fracture Patients

    PubMed Central

    Zheng, Hailiang; Li, Ming; Yin, Pengbin; Peng, Ye; Gao, Yuan; Zhang, Lihai; Tang, Peifu

    2015-01-01

    Background Calcaneal quantitative ultrasound (QUS), which is used in the evaluation of osteoporosis, is believed to be intimately associated with the characteristics of the proximal femur. However, the specific associations of calcaneal QUS with characteristics of the hip sub-regions remain unclear. Design A cross-sectional assessment of 53 osteoporotic patients was performed for the skeletal status of the heel and hip. Methods We prospectively enrolled 53 female osteoporotic patients with femoral fractures. Calcaneal QUS, dual energy X-ray absorptiometry (DXA), and hip structural analysis (HSA) were performed for each patient. Femoral heads were obtained during the surgery, and principal compressive trabeculae (PCT) were extracted by a three-dimensional printing technique-assisted method. Pearson’s correlation between QUS measurement with DXA, HSA-derived parameters and Young’s modulus were calculated in order to evaluate the specific association of QUS with the parameters for the hip sub-regions, including the femoral neck, trochanteric and Ward’s areas, and the femoral shaft, respectively. Results Significant correlations were found between estimated BMD (Est.BMD) and BMD of different sub-regions of proximal femur. However, the correlation coefficient of trochanteric area (r = 0.356, p = 0.009) was higher than that of the neck area (r = 0.297, p = 0.031) and total proximal femur (r = 0.291, p = 0.034). Furthermore, the quantitative ultrasound index (QUI) was significantly correlated with the HSA-derived parameters of the trochanteric area (r value: 0.315–0.356, all p<0.05) as well as with the Young’s modulus of PCT from the femoral head (r = 0.589, p<0.001). Conclusion The calcaneal bone had an intimate association with the trochanteric cancellous bone. To a certain extent, the parameters of the calcaneal QUS can reflect the characteristics of the trochanteric area of the proximal hip, although not specifically reflective of those of the femoral neck

  1. Serum Dioxin Concentrations and Bone Density and Structure in the Seveso Women’s Health Study

    PubMed Central

    Warner, Marcella; Sirtori, Marcella; Fuerst, Thomas; Rauch, Stephen A.; Brambilla, Paolo; Mocarelli, Paolo; Rubinacci, Alessandro

    2013-01-01

    Background: 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), a widespread environmental contaminant, is a known endocrine disruptor. In animal studies, TCDD exposure impairs bone metabolism and increases fragility. To our knowledge, no epidemiologic studies have examined this association. Objectives: On 10 July 1976, a chemical explosion in Seveso, Italy, resulted in the highest known residential exposure to TCDD. In 1996, we initiated the Seveso Women’s Health Study, a retrospective cohort study of the health of the women. In 2008, we followed up the cohort. Here, we evaluated the association between TCDD exposure and bone structure and geometry in adulthood, and considered whether timing of TCDD exposure before achievement of peak bone mass (assumed to occur 2 years after onset of menarche) modified the association. Methods: Individual TCDD concentration was measured in archived serum collected soon after the explosion. In 2008, 350 women who were < 20 years old in 1976 underwent a dual-energy X-ray absorptiometry (DXA) bone scan. Bone mineral density was measured at the lumbar spine and hip, and hip geometry was extracted from hip DXA scans using the hip structural analysis method. Results: Among premenopausal women, TCDD serum levels were associated with some indexes indicating better bone structure in women exposed before peak bone mass (n = 219), with stronger associations in those exposed before 5 years of age (n = 46). In contrast, among postmenopausal women, TCDD levels were associated with evidence of better bone structure in women exposed after peak bone mass (n = 48) than in other women (n = 18). Conclusions: Our current results do not support the hypothesis that postnatal TCDD exposure adversely affects adult bone health. Continued follow-up of women who were youngest at exposure is warranted. Future studies should also focus on those exposed in utero. Citation: Eskenazi B, Warner M, Sirtori M, Fuerst T, Rauch SA, Brambilla P, Mocarelli P, Rubinacci A

  2. Tibolone increases bone mineral density but also relapse in breast cancer survivors: LIBERATE trial bone substudy

    PubMed Central

    2012-01-01

    Introduction The Livial Intervention Following Breast Cancer: Efficacy, Recurrence and Tolerability Endpoints (LIBERATE: Clinical http://Trials.gov number NCT00408863), a randomized, placebo-controlled, double-blind trial that demonstrated that tibolone (Livial), a tissue-selective hormone-replacement therapy (HRT), increased breast cancer (BC) recurrence HR 1.40 (95% CI, 1.14 to 1.70; P = 0.001). A subgroup of women was entered into a study of bone mineral density (BMD). Methods Women with surgically excised primary BC (T1-3, N0-2, M-0) within the last 5 years, complaining of vasomotor symptoms, were assigned to tibolone, 2.5 mg daily, or placebo treatment for a maximum of 5 years. The BMD substudy enrolled 763 patients, using dual-energy X-ray absorptiometry (DXA) scanning at baseline and at 2 years. Results In the bone substudy, 699 of 763 women were eligible (345 allocated to tibolone, and 354, to placebo). After undergoing DXA scans, 300 (43%) women had normal BMD; 317 (45%), osteopenia; and 82 (11.7%), osteoporosis. Low body-mass index (P < 0.001), Asian race (P < 0.001), and late age at menarche (P < 0.04) predicted low bone mass at baseline. Tibolone increased BMD by 3.2% at the lumbar spine and 2.9% at the hip compared with placebo (both P < 0.001). The majority of fractures (55%) occurred in osteopenic patients. Women with normal BMD had increased recurrence with tibolone, 22 (15.6%) of 141 compared with placebo, 11 (6.9%) of 159 (P = 0.016), whereas no increased BC recurrence was seen in women with low BMD; 15 (7.4%) of 204 taking tibolone versus 13 (6.7%) of 195 taking placebo. Conclusions Tibolone is contraindicated after BC treatment, as it increases BMD and BC recurrence. Risk of BC recurrence was elevated in BC women with normal BMD (compared with low) who took tibolone. PMID:22251615

  3. Comparing the accuracy of ES-BC, EIS-GS, and ES Oxi on body composition, autonomic nervous system activity, and cardiac output to standardized assessments

    PubMed Central

    Lewis, John E; Tannenbaum, Stacey L; Gao, Jinrun; Melillo, Angelica B; Long, Evan G; Alonso, Yaima; Konefal, Janet; Woolger, Judi M; Leonard, Susanna; Singh, Prabjot K; Chen, Lawrence; Tiozzo, Eduard

    2011-01-01

    Background and purpose The Electro Sensor Complex (ESC) is software that combines three devices using bioelectrical impedance, galvanic skin response, and spectrophotometry: (1) ES-BC (Electro Sensor-Body Composition; LD Technology, Miami, FL) to assess body composition, (2) EIS-GS (Electro Interstitial Scan-Galvanic Skin; LD Technology) to predict autonomic nervous system activity, and (3) ES Oxi (Electro Sensor Oxi; LD Technology) to assess cardiac output. The objective of this study was to compare each to a standardized assessment: ES-BC to dual-energy X-ray absorptiometry (DXA), EIS-GS to heart rate variability, and ES Oxi to BioZ Dx Diagnostic System (BioZ Dx; SonoSite Inc, Bothell, WA). Patients and methods The study was conducted in two waves. Fifty subjects were assessed for body composition and autonomic nervous system activity. Fifty-one subjects were assessed for cardiac output. Results We found adequate relative and absolute agreement between ES-BC and DXA for fat mass (r = 0.97, P < 0.001) with ES-BC overestimating fat mass by 0.1 kg and for body fat percentage (r = 0.92, P < 0.001) with overestimation of fat percentage by 0.4%. For autonomic nervous system activity, we found marginal relative agreement between EIS-GS and heart rate variability by using EIS-GS as the predictor in a linear regression equation (adjusted R2 = 0.56, P = 0.03). For cardiac output, adequate relative and absolute agreement was found between ES Oxi and BioZ Dx at baseline (r = 0.60, P < 0.001), after the first exercise stage (r = 0.79, P < 0.001), and after the second exercise stage (r = 0.86, P < 0.001). Absolute agreement was found at baseline and after both bouts of exercise; ES Oxi overestimated baseline and stage 1 exercise cardiac output by 0.3 L/minute and 0.1 L/minute, respectively, but exactly estimated stage 2 exercise cardiac output. Conclusion ES-BC and ES Oxi accurately assessed body composition and cardiac output compared to standardized instruments, whereas EIS

  4. Legacy effects of short-term intentional weight loss on total body and thigh composition in overweight and obese older adults

    PubMed Central

    Chmelo, E A; Beavers, D P; Lyles, M F; Marsh, A P; Nicklas, B J; Beavers, K M

    2016-01-01

    Objective: Weight regain following intentional weight loss may negatively impact body composition, accelerating fat regain and increasing risk of physical disability. The purpose of this study was to compare long-term changes in whole body and thigh composition in obese older adults who intentionally lost and then partially regained weight to obese older adults who remained weight stable. Subjects/Methods: This pilot study analyzed total body (dual-energy X-ray absorptiometry (DXA)) and thigh (computed tomography (CT)) composition data collected from 24 older (65–79 years) adults 18 months after completion of a 5-month randomized trial that compared resistance training alone (RT) with RT plus caloric restriction (RT+CR). Results: Mean loss of body mass in the RT+CR group (n=13) was 7.1±2.4 kg during the 5-month intervention (74% fat mass; 26% lean mass; all P<0.01), whereas RT (n=11) remained weight stable (+0.3±1.8 kg; P=0.64). Differential group effects were observed for all DXA and CT body composition measures at 5 months (all P⩽0.01); however, by 23 months, group differences persisted only for total body (RT+CR: 81.6±10.0 kg vs RT: 88.5±14.9 kg; P=0.03) and lean (RT+CR: 50.8±9.3 kg vs RT: 54.4±12.0 kg; P<0.01) mass. All RT+CR participants regained weight from 5 to 23 months (mean gain=+4.8±2.6 kg; P<0.01). Total fat mass and all thigh fat volumes increased, whereas thigh muscle volume decreased, during the postintervention follow-up in RT+CR (all P⩽0.01). In the RT group, body mass did not change from 5 to 23 months (−0.2±0.9 kg; P=0.87). Decreased total thigh volume, driven by the loss of thigh muscle volume, were the only postintervention body composition changes observed in the RT group (both P<0.04). Conclusions: Short-term body composition benefits of an RT+CR intervention may be lost within 18 months after completion of the intervention. PMID:27043417

  5. Training with the International Space Station interim resistive exercise device

    NASA Technical Reports Server (NTRS)

    Schneider, Suzanne M.; Amonette, William E.; Blazine, Kristi; Bentley, Jason; Lee, Stuart M C.; Loehr, James A.; Moore, Alan D Jr; Rapley, Michael; Mulder, Edwin R.; Smith, Scott M.

    2003-01-01

    A unique, interim elastomer-based resistive exercise device (iRED) is being used on the International Space Station. PURPOSE: This study characterized iRED training responses in a 1-g environment by: 1) determining whether 16 wk of high-intensity training with iRED produces increases in muscle strength and volume and bone mineral density (BMD), 2) comparing training responses with iRED to free weights, and 3) comparing iRED training responses at two training volumes. METHODS: Twenty-eight untrained men were assigned to four groups of seven subjects each: a no exercise control group (CON), an iRED group who trained with three sets/exercise (iRED3), a free-weight group (FW) who trained with three sets/exercise, and an iRED group who trained with six sets/exercise (iRED6). Training exercises included squat (SQ), heel raise (HR), and dead lift (DL) exercises, 3 d.wk(-1) for 16 wk. RESULTS: For CON, no changes occurred pre- to posttraining. For iRED3, increases (P< or =0.05) in one-repetition maximum (1-RM) strength (SQ 21 +/- 4%, HR 17 +/- 4%, DL 29 +/- 5%), leg lean mass (3.1 +/- 0.5%) by dual energy x-ray absorptiometry (DXA), and thigh (4.5 +/- 0.9%) and calf (5.9 +/- 0.7%) muscle volume (by magnetic resonance imaging) occurred after training with no changes in BMD (DXA). For FW, increases in 1-RM strength (SQ 22 +/- 5%, HR 24 +/- 3%, DL 41 +/- 7%), whole body (3.0 +/- 1.1%) and leg lean mass (5.4 +/- 1.2%), thigh (9.2 +/- 1.3%) and calf (4.2 +/- 1.0%) muscle volumes, and lumbar BMD (4.2 +/- 0.7%) occurred after training. For iRED6, all responses were similar to iRED3. CONCLUSION: High-intensity training with the iRED produced muscle responses similar to FW but was not effective in stimulating bone. Bed rest and spaceflight studies are needed to evaluate the effectiveness of the iRED to prevent microgravity deconditioning.

  6. Women with Anorexia Nervosa: Finite Element and Trabecular Structure Analysis by Using Flat-Panel Volume CT

    PubMed Central

    Phan, Catherine M.; Misra, Madhusmita; Bredella, Miriam A.; Miller, Karen K.; Fazeli, Pouneh K.; Bayraktar, Harun H.; Klibanski, Anne; Gupta, Rajiv

    2010-01-01

    Purpose: To use finite element modeling based on flat-panel volume computed tomography (CT) and bone mineral density (BMD) provided by dual-energy x-ray absorptiometry (DXA) to compare bone failure load, stiffness, and trabecular structure in women with anorexia nervosa (AN) and age-matched normal-weight control subjects. Materials and Methods: The study was approved by the institutional review board and complied with HIPAA guidelines. Informed consent was obtained. Fourteen women, eight with AN (mean age, 26.6 years) and six control subjects (mean age, 26.3 years), underwent flat-panel volume CT of the distal radius to determine apparent trabecular bone volume fraction (BV/TV), apparent trabecular number (TbN), apparent trabecular thickness (TbTh), and apparent trabecular separation (TbSp). Bone strength and stiffness were calculated from uniaxial compression tests by using finite element models created from flat-panel volume CT. DXA was used to determine BMD of the radius, lumbar spine, and hip. Means ± standard deviations of all variables were calculated for both groups and compared (Student t test). Univariate regression analysis and stepwise regression modeling were performed. Results: Patients with AN had lower values for stiffness (284.77 kN/mm ± 76.14 vs 389.97 kN/mm ± 84.90, P = .04), failure load (4.98 kN ± 1.23 vs 7.01 kN ± 1.52, P = .02), BV/TV (0.32% ± 0.09 vs 0.44% ± 0.02, P = .007), and TbN (1.15 mm−3 ± 0.20 vs 1.43 mm−3 ± 0.13, P = .008) and higher values for TbSp (0.62 mm ± 0.20 vs 0.40 mm ± 0.04, P = .02) compared with normal-weight control subjects. TbTh was lower in women with AN (P = .1). BMD measurements were significantly lower for the AN group. BMD measurements and trabecular parameters (except TbTh) correlated with stiffness and failure load (r = 0.58 to 0.83). Conclusion: Failure load and stiffness are abnormal in women with AN compared with those in normal-weight control subjects and correlate with BMD and trabecular

  7. Development and Validation of an Osteoporosis Self-Assessment Tool for Taiwan (OSTAi) Postmenopausal Women-A Sub-Study of the Taiwan OsteoPorosis Survey (TOPS)

    PubMed Central

    Chen, Jia-Feng; Yu, Shan-Fu; Chiu, Wen-Chan; Hsu, Chung-Yuan; Ko, Chi-Hua; Tsai, Ching-Chou; Cheng, Tien-Tsai

    2015-01-01

    Background To develop an OSTAi tool and compare this with the National Osteoporosis Foundation recommendations in 2013 (NOF 2013) for bone mineral density (BMD) testing among Taiwan postmenopausal women. Methods Taiwan Osteoporosis Association (TOA) conducted a nationwide BMD survey by a bus installed with a dual energy X-ray absorptiometry (DXA) between 2008 and 2011. All of the participants completed questionnaire, which included demographics and risk factors of osteoporotic fracture in FRAX tool. We used the database to analyze potential risk factors for osteoporosis and followed the model by Koh et al. to develop a risk index via multiple variable regression analysis and item reduction. We used the index values to set up a simple algorithm (namely OSTAi) to identify those who need BMD measurement. Receiver operating characteristic (ROC) curve and the area under the curve (AUC) was used to compare the sensitivity/specificity analysis of this model with that of recommendations by NOF 2013. Results A total of 12,175 Taiwan postmenopausal women enrolled in this survey. The index value was derived by age and body weight of the participants according to weighted odds of each risk factor and the selected cutoff value was set at “-1”. There are 6393 (52.5%) participants whose index value is below “-1” and whose risk of osteoporosis was 57.5% (3674/6393). The AUC for OSTAi and NOF 2013 were 0.739 (95% confidence interval (CI), 0.728–0.749, P<0.001) and 0.618 (95% CI, 0.606–0.630, P<0.001), respectively. The sensitivity and specificity of OSTAi, at the selected cutoff value of -1, and NOF 2013 to identify osteoporosis were 73.1%, 62.0% and 78.3%, 45.7%, respectively. Conclusions As OSTA for Asian populations, OSTAi is an useful tool to identify Taiwan postmenopausal women with osteoporosis, In comparison with NOF 2013, OSTAi may be an easier and better tool for referral to BMD measurement by DXA in this area. PMID:26086766

  8. Body size and pubertal development explain ethnic differences in structural geometry at the femur in Asian, Hispanic, and white early adolescent girls living in the U.S.

    PubMed Central

    Osborne, D.L.; Weaver, C.M.; McCabe, L.D.; McCabe, G.M.; Novotny, R.; Van Loan, M.D.; Going, S.; Matkovic, V.; Boushey, C.J.; Savaiano, D.A.

    2012-01-01

    Variation in structural geometry is present in adulthood, but when this variation arises and what influences this variation prior to adulthood remains poorly understood. Ethnicity is commonly the focus of research of skeletal integrity and appears to explain some of the variation in quantification of bone tissue. However, why ethnicity explains variation in skeletal integrity is unclear. Methods Here we examine predictors of bone cross sectional area (CSA) and section modulus (Z), measured using dual-energy X-ray absorptiometry (DXA) and the Advanced Hip Analysis (AHA) program at the narrow neck of the femur in adolescent (9–14 yr) girls (n=479) living in the United States who were classified as Asian, Hispanic, or white if the subject was 75% of a given group based on parental reported ethnicity. Protocols for measuring height and weight follow standardized procedures. Total body lean mass (LM) and total body fat mass (FM) were quantified in kilograms using DXA. Total dietary and total dairy calcium intakes from the previous month were estimated by the use of an electronic semi-quantitative food frequency questionnaire (eFFQ). Physical activity was estimated for the previous year by a validated self-administered modifiable activity questionnaire for adolescents with energy expenditure calculated from the metabolic equivalent (MET) values from the Compendium of Physical Activities. Multiple regression models were developed to predict CSA and Z. Results Age, time from menarche, total body lean mass (LM), total body fat mass (FM), height, total calcium, and total dairy calcium all shared a significant (p<0.05), positive relationship with CSA. Age, time from menarche, LM, FM, and height shared significant (p<0.05), positive relationships with Z. For both CSA and Z, LM was the most important covariate. Physical activity was not a significant predictor of geometry at the femoral neck (p≥0.339), even after removing LM as a covariate. After adjusting for covariates

  9. Height, adiposity and body fat distribution and breast density in young women

    PubMed Central

    2012-01-01

    Introduction Breast density is one of the strongest risk factors for breast cancer, but determinants of breast density in young women remain largely unknown. Methods Associations of height, adiposity and body fat distribution with percentage dense breast volume (%DBV) and absolute dense breast volume (ADBV) were evaluated in a cross-sectional study of 174 healthy women, 25 to 29 years old. Adiposity and body fat distribution were measured by anthropometry and dual-energy X-ray absorptiometry (DXA), while %DBV and ADBV were measured by magnetic resonance imaging. Associations were evaluated using linear mixed-effects models. All tests of statistical significance are two-sided. Results Height was significantly positively associated with %DBV but not ADBV; for each standard deviation (SD) increase in height, %DBV increased by 18.7% in adjusted models. In contrast, all measures of adiposity and body fat distribution were significantly inversely associated with %DBV; a SD increase in body mass index (BMI), percentage fat mass, waist circumference and the android:gynoid fat mass ratio (A:G ratio) was each associated significantly with a 44.4 to 47.0% decrease in %DBV after adjustment for childhood BMI and other covariates. Although associations were weaker than for %DBV, all measures of adiposity and body fat distribution also were significantly inversely associated with ADBV before adjustment for childhood BMI. After adjustment for childhood BMI, however, only the DXA measures of percentage fat mass and A:G ratio remained significant; a SD increase in each was associated with a 13.8 to 19.6% decrease in ADBV. In mutually adjusted analysis, the percentage fat mass and the A:G ratio remained significantly inversely associated with %DBV, but only the A:G ratio was significantly associated with ADBV; a SD increase in the A:G ratio was associated with an 18.5% decrease in ADBV. Conclusion Total adiposity and body fat distribution are independently inversely associated with

  10. Decreased bone mineralization in Children with Noonan Syndrome: Another Consequence of Dysregulated RAS MAPKinase Pathway?

    PubMed Central

    Choudhry, Kiran S.; Grover, Monica; Tran, Alyssa; O'Brian Smith, E.; Ellis, Kenneth J.; Lee, Brendan H.

    2012-01-01

    Introduction Noonan syndrome (NS) is a disorder of RAS- mitogen activated protein kinase (MAPK) pathway with clinical features of skeletal dysplasia. This pathway is essential for regulation of cell differentiation and growth including bone homeostasis. Currently, limited information exists regarding bone mineralization in NS. Material and Methods Using dual-energy X-ray absorptiometry (DXA), bone mineralization was evaluated in 12 subjects (mean age 8.7 years) with clinical features of NS. All subjects underwent genetic testing which showed mutations in PTPN11 gene (N=9) and SOS1 gene (N=1). In a subgroup of subjects with low bone mass, indices of calcium-phosphate metabolism and bone turnover were obtained. Results 50% of subjects had low bone mass as measured by DXA. Z-scores for bone mineral content (BMC) were calculated based on age, gender, height, and ethnicity. Mean BMC z-score was marginally decreased at -0.89 {95% CI -2.01 to 0.23; p=0.1}. Mean total body bone mineral density (BMD) z-score was significantly reduced at -1.87 {95% CI -2.73 to -1.0; p= 0.001}. Mean height percentile was close to -2 SD for this cohort, thus total body BMD z-scores were recalculated, adjusting for height age. Adjusted mean total body BMD z-score was less reduced but still significant at -0.82 {95% CI -1.39 to -0.25; p= 0.009}. Biochemical evaluation for bone turnover was unremarkable except serum IGF- I and IGF-BP3 levels which were low-normal for age. Discussion Children with Noonan syndrome have a significantly lower total body BMD compared to age, gender, ethnicity and height matched controls. In addition, total BMC appears to trend lower in children with Noonan syndrome compared to controls. We conclude that the metabolic bone disease present resulted from a subtle variation in the interplay of osteoclast and osteoblast activity, without clear abnormalities being defined in the metabolism of either. Clinical significance of this finding needs to be validated by larger

  11. Adiposity and cardiovascular risk factors in a large contemporary population of pre-pubertal children

    PubMed Central

    Falaschetti, Emanuela; Hingorani, Aroon D.; Jones, Alexander; Charakida, Marietta; Finer, Nicholas; Whincup, Peter; Lawlor, Debbie A.; Davey Smith, George; Sattar, Naveed; Deanfield, John E.

    2010-01-01

    Aims To examine the associations of several markers of adiposity and a wide range of cardiovascular risk factors and biomarkers in pre-pubertal children. Methods and results Four measures of adiposity,body mass index (BMI), waist circumference, dual-energy X-ray absorptiometry (DXA)-determined fat mass, and leptin concentration, were available in up to 7589 children aged 8.8–11.7 (9.9 mean) years from the Avon Longitudinal Study of Parents and Children (ALSPAC). Thirteen per cent of boys and 18.8% of girls were overweight, and 5.3% of boys and 5% of girls were obese. Body mass index was highly correlated with waist circumference (r = 0.91), DXA fat mass (r = 0.87), and leptin concentration (r = 0.75), and all had similar associations with cardiovascular risk factors. A 1 kg/m2 greater BMI was associated with 1.4mmHg (95% CI 1.25–1.44) higher systolic blood pressure (BP). In 5002 children, a 1 kg/m2 greater BMI was associated with a 0.05 mmol/L (95% CI 0.036–0.055) higher non-high-density lipoprotein (HDL) cholesterol and 0.03 mmol/L (95% CI −0.034 to −0.025) lower HDL cholesterol. There were also graded associations with apolipoproteins A1 and B, interleukin-6, and C-reactive protein. Comparing children who were obese with those who were normal weight, the odds ratio for hypertension was 10.7 (95% CI 7.2–15.9) for boys and 13.5 (95% CI 9.4–19.5) for girls. Conclusion In pre-pubertal UK children, overweight/obesity is common and has broadly similar associations with BP, HDL cholesterol, and non-HDL cholesterol to those observed in adults. Future research should evaluate whether effective interventions to maintain healthy weight in childhood could have important benefits for adult cardiovascular risk. PMID:20972265

  12. Bone Mineral Density Changes among HIV-Uninfected Young Adults in a Randomised Trial of Pre-Exposure Prophylaxis with Tenofovir-Emtricitabine or Placebo in Botswana

    PubMed Central

    Kasonde, Michael; Niska, Richard W.; Rose, Charles; Henderson, Faith L.; Segolodi, Tebogo M.; Turner, Kyle; Smith, Dawn K.; Thigpen, Michael C.; Paxton, Lynn A.

    2014-01-01

    Background Tenofovir-emtricitabine (TDF-FTC) pre-exposure prophylaxis (PrEP) has been found to be effective for prevention of HIV infection in several clinical trials. Two studies of TDF PrEP among men who have sex with men showed slight bone mineral density (BMD) loss. We investigated the effect of TDF and the interaction of TDF and hormonal contraception on BMD among HIV-uninfected African men and women. Method We evaluated the effects on BMD of using daily oral TDF-FTC compared to placebo among heterosexual men and women aged 18–29 years enrolled in the Botswana TDF2 PrEP study. Participants had BMD measurements at baseline and thereafter at 6-month intervals with dual-energy X-ray absorptiometry (DXA) scans at the hip, spine, and forearm. Results A total of 220 participants (108 TDF-FTC, 112 placebo) had baseline DXA BMD measurements at three anatomic sites. Fifteen (6.8%) participants had low baseline BMD (z-score of <−2.0 at any anatomic site), including 3/114 women (2.6%) and 12/106 men (11.3%) (p = 0.02). Low baseline BMD was associated with being underweight (p = 0.02), having high blood urea nitrogen (p = 0.02) or high alkaline phosphatase (p = 0.03), and low creatinine clearance (p = 0.04). BMD losses of >3.0% at any anatomic site at any time after baseline were significantly greater for the TDF-FTC treatment group [34/68 (50.0%) TDF-FTC vs. 26/79 (32.9%) placebo; p = 0.04]. There was a small but significant difference in the mean percent change in BMD from baseline for TDF-FTC versus placebo at all three sites at month 30 [forearm −0.84% (p = 0.01), spine −1.62% (p = 0.0002), hip −1.51% (p = 0.003)]. Conclusion Use of TDF-FTC was associated with a small but statistically significant decrease in BMD at the forearm, hip and lumbar spine. A high percentage (6.8%) of healthy Batswana young adults had abnormal baseline BMD Further evaluation is needed of the longer-term use of TDF in HIV-uninfected persons. Trial

  13. Mid-term study of bone remodeling after femoral cemented stem implantation: comparison between DXA and finite element simulation.

    PubMed

    Herrera, Antonio; Rebollo, Sarai; Ibarz, Elena; Mateo, Jesús; Gabarre, Sergio; Gracia, Luis

    2014-01-01

    This five-year prospective study was designed to investigate periprosthetic bone remodeling associated with two cemented stem models, ABG-II (Stryker) and VerSys (Zimmer), randomly implanted in patients older than 75 years. The sample consisted of 64 cases (32, ABG-II; 32, VerSys). Inclusion criterion was diagnosis of osteoarthritis recommended for cemented total hip arthroplasty. Besides clinical study, Finite Element (FE) simulation was used to analyze biomechanical changes caused by hip arthroplasty. Bone Mineral Density (BMD) measurements showed a progressive increase in bone mass throughout the entire follow-up period for both stems, well correlated with FE results except in Gruen zones 4, 5, 6 for ABG-II and in zones 4, 5 for VerSys, denoting that remodeling in those zones does not depend on mechanical factors but rather on biological or physiological ones. PMID:23725926

  14. Percentage body fat in children and adolescents: Does DXA agree with a four-compartment (4-C) reference model?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Overweight and obese children and adolescents often become obese adults. Hence, intervention strategies are being focused at reducing excess fat gain during childhood. Body fatness, defined at the ratio of body fat to body weight, expressed as a percentage (%Fat), is considered the best body compo...

  15. Three-dimensional parametric mapping in quantitative micro-CT imaging of post-surgery femoral head-neck samples: preliminary results

    PubMed Central

    Giannotti, Stefano; Bottai, Vanna; Panetta, Daniele; De Paola, Gaia; Tripodi, Maria; Citarelli, Carmine; Dell’Osso, Giacomo; Lazzerini, Ilaria; Salvadori, Piero Antonio; Guido, Giulio

    2015-01-01

    Summary Osteoporosis and pathological increased occurrence of fractures are an important public health problem. They may affect patients’ quality of life and even increase mortality of osteoporotic patients, and consequently represent a heavy economic burden for national healthcare systems. The adoption of simple and inexpensive methods for mass screening of population at risk may be the key for an effective prevention. The current clinical standards of diagnosing osteoporosis and assessing the risk of an osteoporotic bone fracture include dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT) for the measurement of bone mineral density (BMD). Micro-computed tomography (micro-CT) is a tomographic imaging technique with very high resolution allowing direct quantification of cancellous bone microarchitecture. The Authors performed micro-CT analysis of the femoral heads harvested from 8 patients who have undergone surgery for hip replacement for primary and secondary degenerative disease to identify possible new morphometric parameters based on the analysis of the distribution of intra-subject microarchitectural parameters through the creation of parametric images. Our results show that the micro-architectural metrics commonly used may not be sufficient for the realistic assessment of bone microarchitecture of the femoral head in patients with hip osteoarthritis. The innovative micro-CT approach considers the entire femoral head in its physiological shape with all its components like cartilage, cortical layer and trabecular region. The future use of these methods for a more detailed study of the reaction of trabecular bone for the internal fixation or prostheses would be desirable. PMID:26811703

  16. No medium-term advantage of electrochemical deposition of hydroxyapatite in cementless femoral stems

    PubMed Central

    Flatøy, Bernhard; Röhrl, Stephan M; Bøe, Berte; Nordsletten, Lars

    2016-01-01

    Background and purpose Hydroxyapatite has been used for a long time as an adjunct to enhance cementless fixation. The benefit of this is still debated, but new methods of hydroxyapatite deposition have emerged, offering possible gains. In order to investigate this further, we compared the migration pattern and periprosthetic bone remodeling in a cementless femoral stem with either electrochemically deposited hydroxyapatite—called Bonemaster (BM)—or a conventional plasma-sprayed hydroxyapatite (HA) coating. Patients and methods 55 hips were randomized to either BM or HA cementless femoral stems. Patients were followed with radiostereometry (RSA), dual-energy X-ray absorptiometry (DXA), radiographic measurements, and hip questionnaires for 5 years. Results For both stems, migration occurred mainly as subsidence and retroversion during the first 3 months. The BM group had a higher retroversion rate of 0.17° per month during this period, as compared to 0.06° per month for the HA group (p = 0.006). Thereafter, there was almost no movement in any direction for both stem types. Bone resorption occurred mainly during the first year, and subsequently decreased to a rate close to what is seen in normal ageing. The greatest total decrease occurred in Gruen zones 1 and 7, similar in the groups at 5 years. There was a slightly higher resorption rate in Gruen zone 7 from 2 to 5 years in the BM group (1.3% per year; p = 0.04), but in a magnitude that would scarcely affect stem stability or survival. Interpretation There were no clinically relevant differences between the 2 stems regarding stability or periprosthetic bone loss at 5 years. Electrochemically deposited HA does not appear to affect fixation or bone remodeling when compared to conventional plasma spraying at 5 years. Thus, at this point, Bonemaster appears to be safe. PMID:26364953

  17. Association with replication between estrogen-related receptor gamma (ESRRgamma) polymorphisms and bone phenotypes in women of European ancestry.

    PubMed

    Elfassihi, Latifa; Giroux, Sylvie; Bureau, Alexandre; Laflamme, Nathalie; Cole, David Ec; Rousseau, François

    2010-04-01

    Osteoporosis is a bone disease characterized by low bone mineral density (BMD), a highly heritable polygenic trait. Women are more prone than men to develop osteoporosis owing to a lower peak bone mass and accelerated bone loss at menopause. Lack of estrogen thus is a major risk factor for osteoporosis. In addition to having strong similarity to the estrogen receptor 1 (ESR1), the orphan nuclear estrogen-related receptor gamma (ESRRgamma) is widely expressed and shows overlap with ESR1 expression in tissues where estrogen has important physiologic functions. For these reasons, we have undertaken a study of ESRRgamma sequence variants in association with bone measurements [heel quantitative ultrasound (QUS) by measurements of broadband ultrasound attenuation (BUA), speed of sound (SOS), and stiffness index (SI) and dual-energy X-ray absorptiometry (DXA) at the femoral neck (FN) and lumbar spine (LS)]. A silent variant was found to be associated with multiple bone measurements (LS, BUA, SOS, and SI), the p values ranging from .006 to .04 in a sample of 5144 Quebec women. The region of this variant was analyzed using the HapMap database and the Gabriel method to define a block of 20 kb. Using the Tagger method, eight TagSNPs were identified and genotyped in a sample of 1335 women. Four of these SNPs capture the five major block haplotypes. One SNP (rs2818964) and one haplotype were significantly associated with multiple bone measures. All SNPs involved in the associations were analyzed in two other sample sets with significant results in the same direction. These results suggest involvement of ESRRgamma in the determination of bone density in women. PMID:19821770

  18. Relevance of 2D radiographic texture analysis for the assessment of 3D bone micro-architecture

    SciTech Connect

    Apostol, Lian; Boudousq, Vincent; Basset, Oliver; Odet, Christophe; Yot, Sophie; Tabary, Joachim; Dinten, Jean-Marc; Boller, Elodie; Kotzki, Pierre-Olivier; Peyrin, Francoise

    2006-09-15

    Although the diagnosis of osteoporosis is mainly based on dual x-ray absorptiometry, it has been shown that trabecular bone micro-architecture is also an important factor in regard to fracture risk. In vivo, techniques based on high-resolution x-ray radiography associated to texture analysis have been proposed to investigate bone micro-architecture, but their relevance for giving pertinent 3D information is unclear. Thirty-three calcaneus and femoral neck bone samples including the cortical shells (diameter: 14 mm, height: 30-40 mm) were imaged using 3D-synchrotron x-ray micro-CT at the ESRF. The 3D reconstructed images with a cubic voxel size of 15 {mu}m were further used for two purposes: (1) quantification of three-dimensional trabecular bone micro-architecture (2) simulation of realistic x-ray radiographs under different acquisition conditions. The simulated x-ray radiographs were then analyzed using a large variety of texture analysis methods (co-occurrence, spectral density, fractal, morphology, etc.). The range of micro-architecture parameters was in agreement with previous studies and rather large, suggesting that the population was representative. More than 350 texture parameters were tested. A small number of them were selected based on their correlation to micro-architectural morphometric parameters. Using this subset of texture parameters, multiple regression allowed one to predict up to 93% of the variance of micro-architecture parameters using three texture features. 2D texture features predicting 3D micro-architecture parameters other than BV/TV were identified. The methodology proposed for evaluating the relationships between 3D micro-architecture and 2D texture parameters may also be used for optimizing the conditions for radiographic imaging. Further work will include the application of the method to physical radiographs. In the future, this approach could be used in combination with DXA to refine osteoporosis diagnosis.

  19. Nutritional status evaluation in patients affected by bethlem myopathy and ullrich congenital muscular dystrophy.

    PubMed

    Toni, Silvia; Morandi, Riccardo; Busacchi, Marcello; Tardini, Lucia; Merlini, Luciano; Battistini, Nino Carlo; Pellegrini, Massimo

    2014-01-01

    Collagen VI mutations lead to disabling myopathies like Bethlem myopathy (BM) and Ullrich congenital muscular dystrophy (UCMD). We have investigated the nutritional and metabolic status of one UCMD and seven BM patients (five female, three male, mean age 31 ± 9 years) in order to find a potential metabolic target for nutritional intervention. For this study, we used standard anthropometric tools, such as BMI evaluation and body circumference measurements. All results were compared to dual-energy X-ray absorptiometry (DXA), considered the "gold standard" method. Energy intake of each patient was evaluated through longitudinal methods (7-day food diary) while resting energy expenditure (REE) was predicted using specific equations and measured by indirect calorimetry. Clinical evaluation included general and nutritional blood and urine laboratory analyses and quantitative muscle strength measurement by hand-held dynamometry. BM and UCMD patients showed an altered body composition, characterized by low free fat mass (FFM) and high fat mass (FM), allowing us to classify them as sarcopenic, and all but one as sarcopenic-obese. Another main result was the negative correlation between REE/FFM ratio (basal energy expenditure per kilograms of fat-free mass) and the severity of the disease, as defined by the muscle megascore (correlation coefficient -0.955, P-value <0.001). We postulate that the increase of the REE/FFM ratio in relation to the severity of the disease may be due to an altered and pathophysiological loss of energetic efficiency at the expense of skeletal muscle. We show that a specific metabolic disequilibrium is related to the severity of the disease, which may represent a target for a nutritional intervention in these patients. PMID:25477818

  20. Nutritional Status Evaluation in Patients Affected by Bethlem Myopathy and Ullrich Congenital Muscular Dystrophy

    PubMed Central

    Toni, Silvia; Morandi, Riccardo; Busacchi, Marcello; Tardini, Lucia; Merlini, Luciano; Battistini, Nino Carlo; Pellegrini, Massimo

    2014-01-01

    Collagen VI mutations lead to disabling myopathies like Bethlem myopathy (BM) and Ullrich congenital muscular dystrophy (UCMD). We have investigated the nutritional and metabolic status of one UCMD and seven BM patients (five female, three male, mean age 31 ± 9 years) in order to find a potential metabolic target for nutritional intervention. For this study, we used standard anthropometric tools, such as BMI evaluation and body circumference measurements. All results were compared to dual-energy X-ray absorptiometry (DXA), considered the “gold standard” method. Energy intake of each patient was evaluated through longitudinal methods (7-day food diary) while resting energy expenditure (REE) was predicted using specific equations and measured by indirect calorimetry. Clinical evaluation included general and nutritional blood and urine laboratory analyses and quantitative muscle strength measurement by hand-held dynamometry. BM and UCMD patients showed an altered body composition, characterized by low free fat mass (FFM) and high fat mass (FM), allowing us to classify them as sarcopenic, and all but one as sarcopenic-obese. Another main result was the negative correlation between REE/FFM ratio (basal energy expenditure per kilograms of fat-free mass) and the severity of the disease, as defined by the muscle megascore (correlation coefficient −0.955, P-value <0.001). We postulate that the increase of the REE/FFM ratio in relation to the severity of the disease may be due to an altered and pathophysiological loss of energetic efficiency at the expense of skeletal muscle. We show that a specific metabolic disequilibrium is related to the severity of the disease, which may represent a target for a nutritional intervention in these patients. PMID:25477818

  1. Systemically alendronate was incorporated into dental tissues but did not cause morphological or mechanical changes in rats teeth.

    PubMed

    Nelson-Filho, Paulo; Lucisano, Marília Pacífico; Da Silva, Raquel Assed Bezerra; Da Silva, Roberto Santana; Serra, Mônica Campos; Gerlach, Raquel Fernanda; Neto, Francisco Carlos Rehder; Carneiro, Zumira Aparecida; Zamarioli, Ariane; Morse, Leslie; Battaglino, Ricardo

    2012-09-01

    This study evaluated the effect of the systemic use of sodium alendronate in rats in vivo. Forty-five Wistar rats aged 36 to 42 days and weighing 200 to 230 g were randomly assigned to a control group (n = 20), which received distilled water, and an experimental group (n = 25), which received 2 weekly doses of 1 mg/kg of chemically pure sodium alendronate. The animals were killed after 60 days of treatment. The tibias were removed for analysis of bone mineral density by dual-energy X-ray absorptiometry (DXA). Then, the maxillary incisors were extracted for analysis of the mineralized dental tissues using fluorescence spectroscopy (FS), scanning electron microscopy (SEM), bright field microscopy (BFM), and cross-sectional microhardness (CSMH) testing. DXA and CSMH data were subjected to statistical analysis by Kruskal-Wallis test (5% significance level). The experimental group presented higher bone mineral density than the control group by DXA. FS analysis revealed presence of alendronate in the mineralized dental tissues of the specimens of the experimental group. Significant morphological differences were not found by SEM and BFM. Enamel and dentin (100 and 300 μm from the dentinoenamel junction) CSMH data did not show significant difference between the control and experimental groups. Based on the obtained results, we conclude that while alendronate increased the bone mineral density and was incorporated into the mineralized dental tissues it did not cause significant alterations in the morphology and microhardness of rat incisor enamel and dentin. PMID:22508272

  2. The effect of lead in bone densitometry

    NASA Astrophysics Data System (ADS)

    Popovic, Marija; McNeill, Fiona E.; Webber, Colin E.; Chettle, David R.

    2004-01-01

    Dual energy X-ray absorptiometry (DXA) is presently considered the standard technique for diagnosis of osteoporosis. It has been suggested that the presence of lead interferes with the accurate measurement of bone mineral density (BMD) by DXA because of the increased attenuation and that an accurate measurement of BMD cannot be determined unless the patient's bone lead content of patients is known. We performed DXA measurements on plaster of Paris phantoms and a Hologic Spine phantom in combination with polyester resin doped with various concentrations of lead. At lead levels which correspond to bone concentrations in occupationally exposed individuals, the suggested increase in densitometric BMD was not detected. Numerical calculations show that the effect of the lead depends upon the two energies of the X-ray beam of a particular device. The discrepancy between the actual and the densitometric BMD increases linearly and is about 0.3% at 100 ppm. Such change cannot be detected by the Hologic QDR 4500A, the device used for this experiment.

  3. Experimental investigation of bone mineral density in Thoroughbreds using quantitative computed tomography.

    PubMed

    Yamada, Kazutaka; Sato, Fumio; Higuchi, Tohru; Nishihara, Kaori; Kayano, Mitsunori; Sasaki, Naoki; Nambo, Yasuo

    2015-01-01

    Bone mineral density (BMD) is one of the indications of the strength and health. BMD measured by quantitative computed tomography (QCT) was compared with that measured by dual energy X-ray absorptiometry (DXA) and radiographic bone aluminum equivalence (RBAE). Limbs were removed from horses that had been euthanized for reasons not associated with this study. Sixteen limbs (left and right metacarpals and metatarsals) from 4 horses were used to compare BMD as measured by QCT with those measured by DXA and RBAE. There was a strong correlation between BMD values measured by QCT and those measured by DXA (R(2)=0.85); correlation was also observed between values obtained by QCT and those obtained by RBAE (R(2)=0.61). To investigate changes in BMD with age, 37 right metacarpal bones, including 7 from horses euthanized because of fracture were examined by QCT. The BMD value of samples from horses dramatically increased until 2 years of age and then plateaued, a pattern similar to the growth curve. The BMD values of bone samples from horses euthanized because of fracture were within the population range, and samples of morbid fracture were not included. The relationship between BMD and age provides a reference for further quantitative studies of bone development and remodeling. Quantitative measurement of BMD using QCT may have great potential for the evaluation of bone biology for breeding and rearing management. PMID:26435681

  4. Experimental investigation of bone mineral density in Thoroughbreds using quantitative computed tomography

    PubMed Central

    YAMADA, Kazutaka; SATO, Fumio; HIGUCHI, Tohru; NISHIHARA, Kaori; KAYANO, Mitsunori; SASAKI, Naoki; NAMBO, Yasuo

    2015-01-01

    ABSTRACT Bone mineral density (BMD) is one of the indications of the strength and health. BMD measured by quantitative computed tomography (QCT) was compared with that measured by dual energy X-ray absorptiometry (DXA) and radiographic bone aluminum equivalence (RBAE). Limbs were removed from horses that had been euthanized for reasons not associated with this study. Sixteen limbs (left and right metacarpals and metatarsals) from 4 horses were used to compare BMD as measured by QCT with those measured by DXA and RBAE. There was a strong correlation between BMD values measured by QCT and those measured by DXA (R2=0.85); correlation was also observed between values obtained by QCT and those obtained by RBAE (R2=0.61). To investigate changes in BMD with age, 37 right metacarpal bones, including 7 from horses euthanized because of fracture were examined by QCT. The BMD value of samples from horses dramatically increased until 2 years of age and then plateaued, a pattern similar to the growth curve. The BMD values of bone samples from horses euthanized because of fracture were within the population range, and samples of morbid fracture were not included. The relationship between BMD and age provides a reference for further quantitative studies of bone development and remodeling. Quantitative measurement of BMD using QCT may have great potential for the evaluation of bone biology for breeding and rearing management. PMID:26435681

  5. Smartphone-Based Bioelectrical Impedance Analysis Devices for Daily Obesity Management.

    PubMed

    Choi, Ahyoung; Kim, Justin Younghyun; Jo, Seongwook; Jee, Jae Hwan; Heymsfield, Steven B; Bhagat, Yusuf A; Kim, Insoo; Cho, Jaegeol

    2015-01-01

    Current bioelectric impedance analysis (BIA) systems are often large, cumbersome devices which require strict electrode placement on the user, thus inhibiting mobile capabilities. In this work, we developed a handheld BIA device that measures impedance from multiple frequencies (5 kHz~200 kHz) with four contact electrodes and evaluated the BIA device against standard body composition analysis systems: a dual-energy X-ray absorptiometry (DXA) system (GE Lunar Prodigy, GE Healthcare, Buckinghamshire, UK) and a whole-body BIA system (InBody S10, InBody, Co. Ltd, Seoul, Korea). In the study, 568 healthy participants, varying widely in body mass index, age, and gender, were recruited at two research centers: the Samsung Medical Center (SMC) in South Korea and the Pennington Biomedical Research Center (PBRC) in the United States. From the measured impedance data, we analyzed individual body fat and skeletal muscle mass by applying linear regression analysis against target reference data. Results indicated strong correlations of impedance measurements between the prototype pathways and corresponding InBody S10 electrical pathways (R = 0.93, p < 0.0001). Additionally, body fat estimates from DXA did not yield significant differences (p > 0.728 (paired t-test), DXA mean body fat 29.45 ± 10.77 kg, estimated body fat 29.52 ± 12.53 kg). Thus, this portable BIA system shows a promising ability to estimate an individual's body composition that is comparable to large stationary BIA systems. PMID:26364636

  6. Bone Density Is Directly Associated With Glomerular Filtration and Metabolic Acidosis but Do Not Predict Fragility Fractures in Men With Moderate Chronic Kidney Disease.

    PubMed

    Lima, Guilherme Alcantara Cunha; de Paula Paranhos-Neto, Francisco; Silva, Luciana Colonese; de Mendonça, Laura Maria Carvalho; Delgado, Alvimar Gonçalves; Leite, Maurilo; Gomes, Carlos Perez; Farias, Maria Lucia Fleiuss

    2016-01-01

    Hyperparathyroidism, vitamin D deficiency, increased fibroblast growth factor-23 (FGF-23), and metabolic acidosis promote bone fragility in chronic kidney disease (CKD). Although useful in predicting fracture risk in the general population, the role of dual-energy X-ray absorptiometry (DXA) in CKD remains uncertain. This cross-sectional study included 51 men aged 50-75 yr with moderate CKD. The stage 4 CKD patients had higher levels of parathyroid hormone (p<0.001), FGF-23 (p=0.029), and lowest 25-hydroxyvitamin D (p=0.016), bicarbonate (p<0.001), total femur (p=0.003), and femoral neck (p=0.011) T-scores compared with stage 3 CKD patients. Total femur and femoral neck T-scores were directly correlated with serum bicarbonate (p=0.003, r=0.447 and p=0.005, r=0.427, respectively) and estimated glomerular filtration rate (p=0.024, r=0.325 and p=0.003, r=0.313, respectively) but were not significantly associated with parathyroid hormone, 25-hydroxyvitamin D, or FGF-23. Only 3.9% of the participants had osteoporosis on DXA scan, whereas 31.4% reported a low-impact fracture. Our data point to a pivotal role of metabolic acidosis for bone impairment and to the inadequacy of DXA to evaluate bone fragility in CKD patients. PMID:24709549

  7. Recommendations for Evaluation and Management of Bone Disease in HIV

    PubMed Central

    Brown, Todd T.; Hoy, Jennifer; Borderi, Marco; Guaraldi, Giovanni; Renjifo, Boris; Vescini, Fabio; Yin, Michael T.; Powderly, William G.

    2015-01-01

    Thirty-four human immunodeficiency virus (HIV) specialists from 16 countries contributed to this project, whose primary aim was to provide guidance on the screening, diagnosis, and monitoring of bone disease in HIV-infected patients. Four clinically important questions in bone disease management were identified, and recommendations, based on literature review and expert opinion, were agreed upon. Risk of fragility fracture should be assessed primarily using the Fracture Risk Assessment Tool (FRAX), without dual-energy X-ray absorptiometry (DXA), in all HIV-infected men aged 40–49 years and HIV-infected premenopausal women aged ≥40 years. DXA should be performed in men aged ≥50 years, postmenopausal women, patients with a history of fragility fracture, patients receiving chronic glucocorticoid treatment, and patients at high risk of falls. In resource-limited settings, FRAX without bone mineral density can be substituted for DXA. Guidelines for antiretroviral therapy should be followed; adjustment should avoid tenofovir disoproxil fumarate or boosted protease inhibitors in at-risk patients. Dietary and lifestyle management strategies for high-risk patients should be employed and antiosteoporosis treatment initiated. PMID:25609682

  8. The Relationships between Anabolic Hormones and Body Composition in Middle-Aged and Elderly Men with Prediabetes: A Cross-Sectional Study

    PubMed Central

    Rabijewski, Michał; Papierska, Lucyna; Piątkiewicz, Paweł

    2016-01-01

    The influence of anabolic hormones and body composition in men with prediabetes (PD) is unknown. In a cross-sectional study we investigated the relationships between total testosterone (TT), calculated free testosterone (cFT), dehydroepiandrosterone sulfate (DHEAS), and insulin-like growth factor 1 (IGF-1) and body composition assessed using dual-energy X-ray absorptiometry (DXA) method in 84 patients with PD (40–80 years) and 56 men in control group. Patients with PD had lower TT, cFT, and DHEAS levels but similar IGF-1 levels in both groups. Patients with PD presented the higher total and abdominal fat as well as the lower total and abdominal lean than control (p < 0.02, p < 0.01, p < 0.05, and p < 0.02, resp.). We observed negative relationship between TT and total fat (p = 0.014) and positive with abdominal lean mass (p = 0.034), while cFT was negatively associated with abdominal (p = 0.02), trunk (p = 0.024), and leg fat (p = 0.037) and positively associated with total (p = 0.022) and trunk lean (p = 0.024). DHEAS were negatively associated with total fat (p = 0.045), and IGF-1 were positively associated with abdominal (p = 0.003) and leg lean (p = 0.015). In conclusion, the lowered anabolic hormones are involved in body composition rearrangement in men with PD. Further studies are needed to establish whether the androgen replacement therapy would be beneficial in men with PD. PMID:27274996

  9. Factors That Contribute to Low Bone Density in Postmenopausal Women in Different Amazonian Communities

    PubMed Central

    Borba-Pinheiro, Cláudio Joaquim; Drigo, Alexandre Janotta; de Alencar Carvalho, Mauro César Gurgel; da Silva, Nádia Souza Lima; Dantas, Estélio Henrique Martin

    2011-01-01

    Background: The aim of this study was to verify socioeconomic differences, nutrition, body balance and quality of life (QoL) in postmenopausal women with low bone mineral density (BMD) in two Amazonian communities. Methods: A total of 42 female volunteers participated in the study. The volunteers were separated into two groups: Villa (n = 20; 53 ± 5.5 years) and City (n = 22; 56 ± 7.9 years). The following evaluation instruments were used: dual energy X-ray absorptiometry (DXA); a socioeconomic questionnaire; a QoL questionnaire; a dietary habits questionnaire; and a balance test. Parametric and nonparametric tests were used. Results: The data showed significant differences in socioeconomic level (Δ%=+15.9%, p = 0.000), lumbar spine L2-L4 (Δ% = +0.10%, p = 0.007), balance (Δ% = +4.3%, p = 0.03) and some important aspects of nutrition, such as the consumption of milk (Δ%=+34%, p = 0.01) and alcohol (+14.8%, p = 0.0001). These significant differences also contributed to the total QoL score (Δ%=+76.2%, p = 0.000) and the majority of the QoL-related functions. Conclusion: This study verified that socioeconomic level, nutritional status, physical activity levels and QoL can influence the BMD of postmenopausal women. The study suggests new strategies for official health organizations to use in order to prevent and treat osteoporosis. In addition, this study can provide an orientation to physical activity, nutrition and medical professionals. PMID:22870468

  10. Discordance in diagnosis of osteoporosis using spine and hip bone densitometry

    PubMed Central

    Moayyeri, Alireza; Soltani, Akbar; Tabari, Nasibeh Khaleghnejad; Sadatsafavi, Mohsen; Hossein-neghad, Arash; Larijani, Bagher

    2005-01-01

    Background Diagnostic discordance for osteoporosis is the observation that the T-score of an individual patient varies from one key measurement site to another, falling into two different diagnostic categories identified by the World Health Organization (WHO) classification system. This study was conducted to evaluate the presence and risk factors for this phenomenon in a large sample of Iranian population. Methods Demographic data, anthropometric measurements, and risk factors for osteoporosis were derived from a database on 4229 patients referred to a community-based outpatient osteoporosis testing center from 2000 to 2003. Dual-energy X-ray absorptiometry (DXA) was performed on L1–L4 lumbar spine and total hip for all cases. Minor discordance was defined as present when the difference between two sites was no more than one WHO diagnostic class. Major discordance was present when one site is osteoporotic and the other is normal. Subjects with incomplete data were excluded. Results In 4188 participants (3848 female, mean age 53.4 ± 11.8 years), major discordance, minor discordance, and concordance of T-scores were seen in 2.7%, 38.9% and 58.3%, respectively. In multivariate logistic regression analysis, older age, menopause, obesity, and belated menopause were recognized as risk factors and hormone replacement therapy as a protective factor against T-score discordance. Conclusion The high prevalence of T-score discordance may lead to problems in interpretation of the densitometry results for some patients. This phenomenon should be regarded as a real and prevalent finding and physicians should develop a particular strategy approaching to these patients. PMID:15762986

  11. A Study to Assess and Correlate Osteoporosis and Periodontitis in Selected Population of Maharashtra

    PubMed Central

    Lohana, Mohini; Abbayya, Keshava; Varma, Siddharth; Zope, Sameer; Kale, Vishwajeet

    2015-01-01

    Background Osteoporosis is a systemic bone disorder characterized by decreased bone mass and increased risk for fracture. It has been proposed as a possible risk factor for periodontal disease progression. Recent literature has shown periodontitis to be a risk indicator for osteoporosis, suggesting a possible two way relationship. However the association between these two diseases still remains unclear leading to a scope of further research in this area. Aim The aim of the present study was to assess and Correlate the severity of osteoporosis and periodontitis by using variables like probing pocket depth, clinical attachment loss, plaque index, body mass index and bone mineral density. Materials and Methods A total of 65 subjects aged between 45-75 years suffering from periodontitis were considered. All subjects were assessed for periodontal disease severity by plaque index (PI), probing pocket depth (PPD) and clinical attachment loss (CAL). The bone mineral density (BMD) of patients was assessed using dual energy X- ray absorptiometry (DXA) at lumbar spine (L1 – L4). The severity of periodontal disease was correlated with severity of osteoporosis. Descriptive statistics like frequency and percentage were calculated for all the variables. Chi-square test was performed to assess the association between the study variables. Result Among the entire group 78.46% had high plaque index score, and the severity of periodontitis increased with increase in plaque index score showing a statistical significance. Osteopenia was observed in 25.33% of the subjects, out of whom 63.15% suffered from severe periodontitis. Osteoporosis was observed in 17.33% of the subjects, and all the subjects (100%) suffered from severe periodontitis. Conclusion The results of the present study suggest that increasing severity of periodontitis increased the risk of osteoporosis and vice versa. We conclude that there is a definite association between periodontitis and osteoporosis. PMID:26266217

  12. Relationship between insulin-like growth factor I, dehydroepiandrosterone sulfate and proresorptive cytokines and bone density in cystic fibrosis

    PubMed Central

    Binello, E.; LeBoff, M. S.; Wohl, M. E.; Rosen, C. J.; Colin, A. A.

    2011-01-01

    Introduction Patients with cystic fibrosis (CF) are known to be at risk for early osteoporosis, and the mechanisms that mediate bone loss are still being delineated. The aim of the present investigation was to investigate if a correlation exists in these patients between skeletal measurements by dual-energy x-ray absorptiometry (DXA) and two anabolic factors, dehydroepiandrosterone (DHEA) and insulin-like growth factor I (IGF-I), and proresorptive factors such as the cytokines interleukin-1β, tumor necrosis factor α, and interleukin-6. Methods We studied 32 outpatients (18 females; mean age: 26.2 ± 7.9 years) at a tertiary care medical center. The subjects had venous samples obtained, underwent anthropometric and bone mineral density (BMD) measurements, and completed a health survey. Serum IGF-I concentrations were below the age-adjusted mean in 78% of the participants, and DHEA sulfate (DHEAS) concentrations were low in 72%. Serum concentrations of all cytokines were on the low side of normal; nonetheless, there was a modest inverse correlation between IL-1β and BMD at all sites. Results In univariate analyses, IGF-I and DHEAS were significant correlates of BMD or bone mineral content. In final multivariate models controlling for anthropometric and other variables of relevance to bone density, only IGF-I was identified as a significant independent skeletal predictor. While alterations in DHEAS, IGF-I, and specific cytokines may contribute to skeletal deficits in patients with CF, of these factors a low IGF-I concentration appears to be most strongly correlated with BMD. Conclusions These findings may have therapeutic implications for enhancing bone density in these patients. PMID:16541207

  13. Reloading partly recovers bone mineral density and mechanical properties in hind limb unloaded rats

    NASA Astrophysics Data System (ADS)

    Zhao, Fan; Li, Dijie; Arfat, Yasir; Chen, Zhihao; Liu, Zonglin; Lin, Yu; Ding, Chong; Sun, Yulong; Hu, Lifang; Shang, Peng; Qian, Airong

    2014-12-01

    Skeletal unloading results in decreased bone formation and bone mass. During long-term space flight, the decreased bone mass is impossible to fully recover. Therefore, it is necessary to develop the effective countermeasures to prevent spaceflight-induced bone loss. Hindlimb Unloading (HLU) simulates effects of weightlessness and is utilized extensively to examine the response of musculoskeletal systems to certain aspects of space flight. The purpose of this study is to investigate the effects of a 4-week HLU in rats and subsequent reloading on the bone mineral density (BMD) and mechanical properties of load-bearing bones. After HLU for 4 weeks, the rats were then subjected to reloading for 1 week, 2 weeks and 3 weeks, and then the BMD of the femur, tibia and lumbar spine in rats were assessed by dual energy X-ray absorptiometry (DXA) every week. The mechanical properties of the femur were determined by three-point bending test. Dry bone and bone ash of femur were obtained through Oven-Drying method and were weighed respectively. Serum alkaline phosphatase (ALP) and serum calcium were examined through ELISA and Atomic Absorption Spectrometry. The results showed that 4 weeks of HLU significantly decreased body weight of rats and reloading for 1 week, 2 weeks or 3 weeks did not recover the weight loss induced by HLU. However, after 2 weeks of reloading, BMD of femur and tibia of HLU rats partly recovered (+10.4%, +2.3%). After 3 weeks of reloading, the reduction of BMD, energy absorption, bone mass and mechanical properties of bone induced by HLU recovered to some extent. The changes in serum ALP and serum calcium induced by HLU were also recovered after reloading. Our results indicate that a short period of reloading could not completely recover bone after a period of unloading, thus some interventions such as mechanical vibration or pharmaceuticals are necessary to help bone recovery.

  14. Lower periprosthetic bone loss and good fixation of an ultra-short stem compared to a conventional stem in uncemented total hip arthroplasty

    PubMed Central

    Salemyr, Mats; Muren, Olle; Ahl, Torbjörn; Bodén, Henrik; Eisler, Thomas; Stark, André; Sköldenberg, Olof

    2015-01-01

    Background and purpose — We hypothesized that an ultra-short stem would load the proximal femur in a more physiological way and could therefore reduce the adaptive periprosthetic bone loss known as stress shielding. Patients and methods — 51 patients with primary hip osteoarthritis were randomized to total hip arthroplasty (THA) with either an ultra-short stem or a conventional tapered stem. The primary endpoint was change in periprosthetic bone mineral density (BMD), measured with dual-energy x-ray absorptiometry (DXA), in Gruen zones 1 and 7, two years after surgery. Secondary endpoints were change in periprosthetic BMD in the entire periprosthetic region, i.e. Gruen zones 1 through 7, stem migration measured with radiostereometric analysis (RSA), and function measured with self-administered functional scores. Results — The periprosthetic decrease in BMD was statistically significantly lower with the ultra-short stem. In Gruen zone 1, the mean difference was 18% (95% CI: −27% to −10%). In zone 7, the difference was 5% (CI: −12% to −3%) and for Gruen zones 1–7 the difference was also 5% (CI: −9% to −2%). During the first 6 weeks postoperatively, the ultra-short stems migrated 0.77 mm more on average than the conventional stems. 3 months after surgery, no further migration was seen. The functional scores improved during the study and were similar in the 2 groups. Interpretation — Up to 2 years after total hip arthroplasty, compared to the conventional tapered stem the ultra-short uncemented anatomical stem induced lower periprosthetic bone loss and had equally excellent stem fixation and clinical outcome. PMID:26134386

  15. Early loss of bone mineral density is correlated with a gain of fat mass in patients starting a protease inhibitor containing regimen: the prospective Lipotrip study

    PubMed Central

    2013-01-01

    Background HIV-infected patients starting antiretroviral treatment (ART) experience deep and early disorders in fat and bone metabolism, leading to concomitant changes in fat mass and bone mineral density. Methods We conducted a prospective study in treatment-naive HIV-infected patients randomized to receive two nucleoside reverse transcriptase inhibitors in combination with either a protease inhibitor (PI) or a non-nucleosidic reverse transcriptase inhibitor (NNRTI), to evaluate early changes in body composition, bone mineral density and metabolic markers as differentially induced by antiretroviral therapies. We measured changes in markers of carbohydrate, of fat and bone metabolism, and, using dual-emission X-ray absorptiometry (DXA), body composition and bone mineral density (BMD). Complete data on changes between baseline and after 21 months treatment were available for 35 patients (16 in the PI group and 19 in the NNRTI group). Results A significant gain in BMI and in total and lower limb fat mass was recorded only in patients receiving PI. A loss of lumbar BMD was observed in both groups, being higher with PI. Plasma markers of bone metabolism (alkaline phosphatase, osteocalcin, collagen crosslaps) and levels of parathormone and of 1,25diOH-vitamin D3 significantly increased in both groups, concomitant with a decline in 25OH-vitamin D3. Lipids and glucose levels increased in both groups but rise in triglyceride was more pronounced with PI. A correlation between loss of BMD and gain of fat mass is observed in patients starting PI. Conclusions We evidenced an early effect of ART on lipid and bone metabolisms. PI lead to a significant gain in fat mass correlated with a sharp drop in BMD but active bone remodelling is evident with all antiretroviral treatments, associated with low vitamin D levels and hyperparathyroidism. In parallel, signs of metabolic restoration are evident. However, early increases in lean and fat mass, triglycerides, waist circumference and

  16. IINFLUENCE OF THE IMMUNOSUPPRESSANT TACROLIMUS (FK-506) ON THE FLEXURAL STRENGTH OF FEMUR: A STUDY IN RATS

    PubMed Central

    Pithon, Matheus Melo; de Andrade, Ana Carolina Dias Viana; de Brito Rodrigues, Vinícius; dos Santos, Rogério Lacerda

    2015-01-01

    Objective: To evaluate the resistance to femoral fractures among rats treated with the immunosuppressant tacrolimus FK-506 and compare these to untreated rats and rats treated with placebo. Methods: Ninety male Wistar rats were used. The animals were nine weeks old and weighed between 220 g and 280 g. The immunosuppressive agent tacrolimus was used in this study at a dose of 2 mg/kg/day, administered orally. The suspension was administered using an insulin syringe, and the maintenance therapeutic dose was sufficient to maintain the immunosuppressive activity. The animals were randomly divided into three groups (n = 30): group 1, no substance administered; group 2, administration of the immunosuppressant tacrolimus FK-506; and group 3, administration of the vehicle alone. Treatment with FK-506 was administered for 28 days. Total leukocyte counts and differential counts (lymphocytes, monocytes, eosinophils and neutrophils) were evaluated in order to monitor the immunosuppressive effect. Bone densitometry analysis by means of dual-energy x-ray absorptiometry (DXA) was also performed before and after administration of the drug. To evaluate the resistance to flexion, a support device was developed so that mechanical tests using an EMIC universal testing machine could be carried out. Results: The results from the flexion resistance tests showed statistical differences between groups 1 and 2 (p = 0.001) and between groups 2 and 3 (p = 0.001). No statistical difference was found between groups 1 and 3 (p = 0.995). Conclusions: The femurs of rats treated with the immunosuppressive agent had lower mechanical strength than did those of normal rats and those that received placebo. PMID:27022554

  17. Increased migration of uncemented acetabular cups in female total hip arthroplasty patients with low systemic bone mineral density

    PubMed Central

    Finnilä, Sami; Moritz, Niko; SvedströM, Erkki; Alm, Jessica J; Aro, Hannu T

    2016-01-01

    Background and purpose Low bone mineral density (BMD) may jeopardize the initial component stability and delay osseointegration of uncemented acetabular cups in total hip arthroplasty (THA). We measured the migration of uncemented cups in women with low or normal BMD. Patients and methods We used radiostereometric analysis (RSA) to measure the migration of hydroxyapatite-coated titanium alloy cups with alumina-on-alumina bearings in THA of 34 female patients with a median age of 64 (41–78) years. 10 patients had normal BMD and 24 patients had low systemic BMD (T-score ≤ −1) based on dual-energy X-ray absorptiometry (DXA). Cup migration was followed with RSA for 2 years. Radiographic follow-up was done at a median of 8 (2–10) years. Results Patients with normal BMD did not show a statistically significant cup migration after the settling period of 3 months, while patients with low BMD had a continuous proximal migration between 3 and 12 months (p = 0.03). These differences in cup migration persisted at 24 months. Based on the perceived risk of cup revision, 14 of the 24 cases were “at risk” (proximal translation of 0.2 to 1.0 mm) in the low-BMD group and 2 of the10 cases were “at risk” in the normal-BMD group (odds ratio (OR) = 8.0, 95% CI: 1.3–48). The radiographic follow-up showed no radiolucent lines or osteolysis. 2 cups have been revised for fractures of the ceramic bearings, but none for loosening. Interpretation Low BMD contributed to cup migration beyond the settling period of 3 months, but the migrating cups appeared to osseointegrate eventually. PMID:26569616

  18. Changes in Physical Activity and Body Composition in Postmenopausal Women over Time

    PubMed Central

    Sims, Stacy T.; Kubo, Jessica; Desai, Manisha; Bea, Jennifer; Beasley, Jeannette M.; Manson, JoAnn E.; Allison, Matthew; Seguin, Rebecca A.; Chen, Zhao; Michael, Yvonne L.; Sullivan, Shannon D.; Beresford, Shirley; Stefanick, Marcia L.

    2013-01-01

    Purpose Higher physical activity (PA) has been associated with greater attenuation of body-fat gain and preservation of lean mass across the lifespan. These analyses aimed to determine relationships of change in PA to changes in fat and lean body mass in a longitudinal prospective study of postmenopausal women. Methods Among 11,491 women enrolled at three Women’s Health Initiative (WHI) clinical centers were selected to undergo dual-energy x-ray absorptiometry (DXA), 8,352 had baseline body composition measurements, with at least one repeated measure at yr 1, 3, and 6. PA data were obtained by self-report at baseline, 3 and 6 yr of follow-up. Time-varying PA impact on change in lean and fat mass during the six-yr study period for age groups (50–59y, 60–69y, 70–79y) was estimated using mixed effects linear regression. Results Baseline PA and body composition differed significantly among the three age groups. The association of change in fat mass from baseline and time-varying PA differed across the three age groups (p=0.0006). In women aged 50–59, gain in fat mass from baseline was attenuated with higher levels of physical activity. Women aged 70–79 lost fat mass at all PA levels. In contrast, change in lean mass from baseline and time-varying PA did not differ by age group (p=0.1935). Conclusions The association between PA and change in fat mass varies by age group, with younger, but not older, women benefitting from higher levels of aerobic PA. Higher levels of aerobic activity are not associated with changes in lean mass, which tends to decrease in older women regardless of activity level. Greater attention to resistance training exercises may be needed to prevent lean mass loss as women age. PMID:23439422

  19. Proximal Femoral Geometry as Fracture Risk Factor in Female Patients with Osteoporotic Hip Fracture

    PubMed Central

    Han, Jun

    2016-01-01

    Background Proximal femoral geometry may be a risk factor of osteoporotic hip fractures. However, there existed great differences among studies depending on race, sex and age of subjects. The purpose of the present study is to analyze proximal femoral geometry and bone mineral density (BMD) in the osteoporotic hip fracture patients. Furthermore, we investigated proximal femoral geometric parameters affecting fractures, and whether the geometric parameters could be an independent risk factor of fractures regardless of BMD. Methods This study was conducted on 197 women aged 65 years or more who were hospitalized with osteoporotic hip fracture (femur neck fractures ; 84, intertrochanteric fractures; 113). Control group included 551 women who visited to check osteoporosis. Femur BMD and proximal femoral geometry for all subjects were measured using dual energy X-ray absorptiometry (DXA), and compared between the control and fracture groups. Besides, proximal femoral geometric parameters associated with fractures were statistically analyzed. Results There were statistically significant differences in the age and weight, cross-sectional area (CSA)/length/width of the femoral neck and BMD of the proximal femur between fracture group and control group. BMD of the proximal femur in the control group was higher than in the fracture group. For the femoral neck fractures group, the odds ratio (OR) for fractures decrease in the CSA and neck length (NL) of the femur increased by 1.97 times and 1.73 times respectively, regardless of BMD. The OR for fractures increase in the femoral neck width increased by 1.53 times. In the intertrochanteric fracture group, the OR for fractures increase in the femoral neck width increased by 1.45 times regardless of BMD. Conclusions We found that an increase of the femoral neck width could be a proximal femoral geometric parameter which plays important roles as a risk factor for fracture independently of BMD. PMID:27622182

  20. Meconium Tenofovir Concentrations and Growth and Bone Outcomes in Prenatally Tenofovir Exposed HIV-Uninfected Children

    PubMed Central

    Himes, Sarah K.; Wu, Julia W.; Jacobson, Denise L.; Tassiopoulos, Katherine; Hazra, Rohan; Kacanek, Deborah; Van Dyke, Russell B.; Rich, Kenneth C.; Siberry, George K.; Huestis, Marilyn A.

    2015-01-01

    Background Maternal tenofovir disoproxil fumarate (TDF) treatment among HIV-infected pregnant women results in fetal tenofovir (TFV) exposure. Fetal TFV toxicity was demonstrated in animals, but most clinical investigations have not observed toxicity in humans. Methods We evaluated HIV-exposed, uninfected infants in the SMARTT cohort of the Pediatric HIV/AIDS Cohort Study whose mothers were prescribed TDF for ≥8 third trimester weeks. Infant dual-energy X-ray absorptiometry (DXA) scans were obtained at 0–4 weeks to measure whole body bone mineral content (BMC). Meconium TFV concentrations were quantified by liquid chromatography-tandem mass spectrometry. Results Fifty-eight TFV-exposed infants had meconium TFV quantified. Detectable concentrations were 11–48,100 ng/g; 3 infants had undetectable concentrations. Maternal TDF prescription duration ranged from 8–41 gestational weeks; infant gestational ages were 36–41 weeks. Meconium TFV concentrations were not correlated with TFV exposure duration or timing and did not vary by concomitant prescription of protease inhibitors. Increased meconium TFV concentrations were associated with greater gestational ages (ρ=0.29, P=0.03) and lower maternal plasma HIV RNA before delivery (ρ=−0.29, P=0.04). Meconium TFV concentrations were not associated with infant weight, length (n=58), or BMC (n=49). Conclusions For the first time, we explored associations between meconium TFV concentrations and infant growth and bone measurements; we did not observe a meconium concentration-dependent relationship for these infant outcomes. These findings support other clinical research failing to show dose-response relationships for growth and bone outcomes among intrauterine TFV-exposed infants. High meconium TFV concentrations correlated with low maternal viral load, suggesting maternal TDF adherence significantly contributes to meconium TFV concentrations. PMID:25961889

  1. Effect of paracentesis on metabolic activity in patients with advanced cirrhosis and ascites.

    PubMed

    Knudsen, Anne Wilkens; Krag, Aleksander; Nordgaard-Lassen, Inge; Frandsen, Erik; Tofteng, Flemming; Mortensen, Christian; Becker, Ulrik

    2016-05-01

    Objective Patients with decompensated cirrhosis often suffer from malnutrition. To enable appropriate nutritional supplementation a correct estimation of resting energy expenditure (REE) is needed. It is, however, unclear whether the volume of ascites should be included or not in the calculations of the REE. Material and methods In 19 patients with cirrhosis and ascites, measurements of REE by indirect calorimetry were performed before paracentesis, after paracentesis, and four weeks after paracentesis. Moreover, handgrip strength (HGS), dual X-ray absorptiometry (DXA), and biochemistry were assessed. Results Calculated and measured REE differed more than 10% in 63% of the patients at baseline. By including the weight of ascites in the calculation of REE, the REE was overestimated by 283 (-602-1381) kJ/day (p = 0.69). By subtracting the weight of ascites in the calculation of REE, it was underestimated by -379 (-1915 - 219) kJ/day, (p  = 0.06). Patients in whom measured REE decreased after paracentesis had higher middle arterial pressure (MAP) (p = 0.02) and p-sodium (p = 0.02) at baseline. Low HGS (M: <30 kg; W < 20 kg) was evident in 68% of the patients. T-scores revealed osteopenia and osteoporosis in 58% and 16%, respectively. Reduced vitamin D levels (<50 nmol/l) were found in 68%. Conclusions The presence of ascites seems to increase REE, why we suggest that when REE is calculated, the weight of ascites should be included. Indirect calorimetry is, however, preferable for REE estimation. More than two-third of patients with ascites suffer from muscle weakness and/or osteopenia. PMID:26673350

  2. Experiences with the Plasmacup--early stability, wear, remodelling, and outcome.

    PubMed

    Wilkinson, J Mark; Gordon, Andrew; Stockley, Ian

    2003-01-01

    Whilst advances in cementing technique have led to improvement in the survival of cemented femoral stems in total hip arthroplasty (THA), cup failure due to aseptic loosening remains a major clinical problem. These observations have led to a move away from cemented cup designs, particularly in young patients, towards uncemented implants. The Plasmacup is a hemispherical, press-fit, cementless, titanium-shelled, acetabular component with a polyethylene liner. In this article we review our experience of its pattern of early migration, wear, bone remodelling, and mid-term survival. In 18 cups followed for 2 years in subjects with a mean age at operation of 58 years, the mean total vectorial cup migration was 0.75 mm, and cup orientation remained stable (EBRA method). The mean polyethylene linear wear rate over this period was 0.21 mm/year. In 27 cups followed for 6 months using dual-energy X-ray absorptiometry (DXA), average bone loss was -5%, and the pelvic bone-remodelling pattern was consistent with the rim-loading principle of the cup design. In a clinical review of the outcome of 128 cups in 104 patients with a mean age at operation of 51 years and follow-up of 59 months, we found that 82% of patients had a good or very good Merle D'Aubigne score, and cup survival rate was 98% (Kaplan-Meier). Four cups had small radiographic areas of focal osteolysis and three had been revised (two for recurrent dislocation and one for deep sepsis; none were revised for aseptic loosening). The mean linear wear rate in this series was 0.14 mm/year. In conclusion, the Plasmacup shows satisfactory early stability, a wear rate similar to other uncemented cups, and favourable mid-term clinical function and survival rates. PMID:14565679

  3. Predicting Trabecular Bone Stiffness from Clinical Cone-Beam CT and HR-pQCT Data; an In Vitro Study Using Finite Element Analysis

    PubMed Central

    Moreno, Rodrigo; Brismar, Torkel B.; Pahr, Dieter H.; Smedby, Örjan

    2016-01-01

    Stiffness and shear moduli of human trabecular bone may be analyzed in vivo by finite element (FE) analysis from image data obtained by clinical imaging equipment such as high resolution peripheral quantitative computed tomography (HR-pQCT). In clinical practice today, this is done in the peripheral skeleton like the wrist and heel. In this cadaveric bone study, fourteen bone specimens from the wrist were imaged by two dental cone beam computed tomography (CBCT) devices and one HR-pQCT device as well as by dual energy X-ray absorptiometry (DXA). Histomorphometric measurements from micro-CT data were used as gold standard. The image processing was done with an in-house developed code based on the automated region growing (ARG) algorithm. Evaluation of how well stiffness (Young’s modulus E3) and minimum shear modulus from the 12, 13, or 23 could be predicted from the CBCT and HR-pQCT imaging data was studied and compared to FE analysis from the micro-CT imaging data. Strong correlations were found between the clinical machines and micro-CT regarding trabecular bone structure parameters, such as bone volume over total volume, trabecular thickness, trabecular number and trabecular nodes (varying from 0.79 to 0.96). The two CBCT devices as well as the HR-pQCT showed the ability to predict stiffness and shear, with adjusted R2-values between 0.78 and 0.92, based on data derived through our in-house developed code based on the ARG algorithm. These findings indicate that clinically used CBCT may be a feasible method for clinical studies of bone structure and mechanical properties in future osteoporosis research. PMID:27513664

  4. Modifiable risk factors associated with bone deficits in childhood cancer survivors

    PubMed Central

    2012-01-01

    Background To determine the prevalence and severity of bone deficits in a cohort of childhood cancer survivors (CCS) compared to a healthy sibling control group, and the modifiable factors associated with bone deficits in CCS. Methods Cross-sectional study of bone health in 319 CCS and 208 healthy sibling controls. Bone mineral density (BMD) was measured by dual-energy x-ray absorptiometry (DXA). Generalized estimating equations were used to compare measures between CCS and controls. Among CCS, multivariable logistic regression was used to evaluate odds ratios for BMD Z-score ≤ -1. Results All subjects were younger than 18 years of age. Average time since treatment was 10.1 years (range 4.3 - 17.8 years). CCS were 3.3 times more likely to have whole body BMD Z-score ≤ -1 than controls (95% CI: 1.4-7.8; p = 0.007) and 1.7 times more likely to have lumbar spine BMD Z-score ≤ -1 than controls (95% CI: 1.0-2.7; p = 0.03). Among CCS, hypogonadism, lower lean body mass, higher daily television/computer screen time, lower physical activity, and higher inflammatory marker IL-6, increased the odds of having a BMD Z-score ≤ -1. Conclusions CCS, less than 18 years of age, have bone deficits compared to a healthy control group. Sedentary lifestyle and inflammation may play a role in bone deficits in CCS. Counseling CCS and their caretakers on decreasing television/computer screen time and increasing activity may improve bone health. PMID:22455440

  5. The Association between Newborn Regional Body Composition and Cord Blood Concentrations of C-Peptide and Insulin-Like Growth Factor I

    PubMed Central

    Carlsen, Emma M.; Renault, Kristina M.; Jensen, Rikke B.; Nørgaard, Kirsten; Jensen, Jens-Erik B.; Nilas, Lisbeth; Cortes, Dina; Michaelsen, Kim F.; Pryds, Ole

    2015-01-01

    Background Third trimester fetal growth is partially regulated by C-peptide and insulin-like growth factor I (IGF-I). Prenatal exposures including maternal obesity and high gestational weight gain as well as high birth weight have been linked to subsequent metabolic disease. We evaluated the associations between newborn regional body composition and cord blood levels of C-peptide and IGF-I. Methods We prospectively included obese and normal-weight mothers and their newborns; cord blood was collected and frozen. Analyses of C-peptide and IGF-I were performed simultaneously, after recruitment was completed. Newborn regional body composition was assessed with dual-energy X-ray absorptiometry scanning (DXA) within 48 hours of birth. Results Three hundred thirty-six term infants were eligible to participate in the study; of whom 174 (52%) infants had cord blood taken. Total, abdominal and arm and leg fat mass were positively associated with C-peptide (p < 0.001). Arm and leg fat mass was associated with IGF-I concentration: 28 g [95% confidence interval: 4, 53] per doubling of IGF-I. There was no association between total or abdominal fat mass and IGF-I. Fat-free mass was positively associated with both C-peptide (p < 0.001) and IGF-I (p = 0.004). Conclusion Peripheral fat tissue accumulation was associated with cord blood C-peptide and IGF-I. Total and abdominal fat masses were related to C-peptide but not to IGF-I. Thus, newborn adiposity is partially mediated through C-peptide and early linear growth is associated with IGF-I. PMID:26151559

  6. Periprosthetic tibial bone mineral density changes after total knee arthroplasty

    PubMed Central

    Jaroma, Antti; Soininvaara, Tarja; Kröger, Heikki

    2016-01-01

    Background and purpose Total knee arthroplasty (TKA) may cause postoperative periprosthetic bone loss due to stress shielding. Bone also adapts to mechanical alterations such as correction of malalignment. We investigated medium-term changes in bone mineral density (BMD) in tibial periprosthetic bone after TKA. Patients and methods 86 TKA patients were prospectively measured with dual-energy X-ray absorptiometry (DXA), the baseline measurement being within 1 week after TKA and the follow-up measurements being at 3 and 6 months, and at 1, 2, 4, and 7 years postoperatively. Long standing radiographs were taken and clinical evaluation was done with the American Knee Society (AKS) score. Results The baseline BMD of the medial tibial metaphyseal region of interest (ROI) was higher in the varus aligned knees (25%; p < 0.001). Medial metaphyseal BMD decreased in subjects with preoperatively varus aligned knees (13%, p < 0.001) and in those with preoperatively valgus aligned knees (12%, p = 0.02) between the baseline and 7-year measurements. No statistically significant changes in BMD were detected in lateral metaphyseal ROIs. No implant failures or revision surgery due to tibial problems occurred. Interpretation Tibial metaphyseal periprosthetic bone is remodeled after TKA due to mechanical axis correction, resulting in more balanced bone stock below the tibial tray. The diaphyseal BMD remains unchanged after the initial drop, within 3–6 months. This remodeling process was related to good component survival, as there were no implant failures or revision operations due to tibial problems in this medium-term follow-up. PMID:27120266

  7. Bone mineral density and factors influencing it in Asian Indian population with type 2 diabetes mellitus

    PubMed Central

    Kamalanathan, Sadishkumar; Nambiar, Vimal; Shivane, Vyankatesh; Bandgar, Tushar; Menon, Padmavathy; Shah, Nalini

    2014-01-01

    Objective: To assess bone mineral density (BMD) in type 2 diabetes mellitus (T2DM) patients and its relation, if any, to clinical, hormonal and metabolic factors. Materials and Methods: A prospective evaluation of 194 T2DM patients (97 men and 97 women) was carried out. BMD was done with dual energy X-ray absorptiometry (DXA) at the lumbar spine and total hip. Physical activity, nutritional intake and sunlight exposure were calculated. Biochemical and hormonal tests included serum 25 hydroxy vitamin D [25(OH) D], parathyroid hormone, estrogen, testosterone and urinary calcium-creatinine ratio. Glycosylated hemoglobin and complete lipid profiles were done in patients with diabetes. Five hundred and seventy one non-diabetic controls (262 males and 309 females) were evaluated for BMD alone. Results: BMD was normal (Z score > -2) in 156 (80.5%) and low (Z score ≤ -2) in 38 (19.5%) patients in the diabetes study group. BMD in the diabetes group was significantly higher than the control group in both sexes at the hip and spine. The difference was no longer significant on analysis of a BMI matched control subgroup. Weight and BMI showed significant correlation to BMD. Duration of T2DM, degree of glycemic control, use of drugs like statins and thiazolidinediones, 25(OH) D levels, calcium intake, sunlight exposure and physical activity did not significantly affect BMD in this cohort of individuals with diabetes. Conclusions: Bone mineral density of Asian Indian T2DM subjects was similar to that of healthy volunteers in this study. PMID:25364679

  8. Relationship Between Body Composition Parameters and Metabolic Syndrome in Young Thai Adults

    PubMed Central

    Namwongprom, Sirianong; Rerkasem, Kittipan; Wongthanee, Antika; Pruenglampoo, Sakda; Mangklabruks, Ampica

    2014-01-01

    Objective: The aim of this study was to evaluate the relationship between body composition parameters, i.e. waist circumference, android fat mass (AFM), gynoid fat mass (GFM), android to gynoid fat mass ratio (AG ratio) and metabolic syndrome (MS) risk components in young Thai adults. Methods: This was a cross-sectional study conducted among 391 adolescents (174 male, 217 female). The body mass index (BMI), waist circumference, blood pressure, triglyceride, high-density lipoprotein (HDL) cholesterol and glucose levels were determined. AFM, GFM and AG ratio were assessed by dual-energy X-ray absorptiometry (DXA). Linear regression analysis was done to assess the relationship of waist circumference, AFM, GFM and AG ratio with MS risk components’ score, separately. Results: Among 391 young adults aged 18.5-21.8 years, MS was found in 5.9%. Participants with MS (n=23) had a significantly higher weight, height and BMI than those without MS. There was no statistically significant difference in bone mineral density between the two groups. At univariable linear regression analysis, waist circumferences, AFM, GFM and AG ratio showed significant relationship with MS risk components’ score. However, after adjusting for gender, birth weight and BMI, AG ratio demonstrated greater relationship with MS risk components’ score (β 1.89, 95%CI 1.096-2.978) than waist circumference (β 0.046, 95%CI 0.033-0.058) and AFM (β 0.979, 95%CI 0.667-1.290). No significant association was observed between GFM and MS risk components’ score (β 0.077, 95%CI -0.089-0.243). Conclusion: The results from this study indicated that AG ratio is a stronger predictor of MS than waist circumference and AFM in young Thai adults. The role of AG ratio for the diagnosis of MS needs to be further investigated. PMID:25541893

  9. Associations of Obesity Genes with Obesity-related Outcomes in Multiethnic Children

    PubMed Central

    Klimentidis, Yann C.; Chen, Guo-Bo; López-Alarcón, Mardia; Harris, Jacqueline J.; Duarte, Christine W.; Fernández, José R.

    2012-01-01

    Background and Aims Genome-wide association studies (GWAS) have identified several loci that are associated with body mass index (BMI = kg/m2). However, little is known regarding whether the genetic basis of BMI differs among children of diverse racial/ethnic backgrounds, how the cumulative effect of these genes influences weight, or the contribution of these variants to body composition. This study examined the association between 17 GWAS-identified loci located in 16 genes and body-composition phenotypes in a multiethnic pediatric sample and evaluated the association of a composite genetic risk score with these phenotypes. Methods Anthropometric measures of BMI, waist circumference and waist-to-hip ratio were obtained in a sample of 298 children. Lean and fat mass were obtained from dual-energy X-ray absorptiometry (DXA). Genotypes of 17 single nucleotide polymorphisms (SNPs) were tested for association with the phenotypic measures, adjusted by standard covariates and estimates of genetic admixture. Results Both SNPs rs8050136 and rs9939609 in FTO were associated with BMI and waist circumference in a direction opposite to that observed among adults, and an inverse association was detected between the risk variant in MC4R and total lean body mass. Lean body mass mediated the association between TMEM18 and BMI. The association between the genetic risk score and body composition differed according to ethnic/racial classification. Conclusions Our findings suggest that genetic associations with BMI among children are different from those in adults, that some loci may operate through lean body mass, and that genetic risk scores will not have universal applicability across ethnic/racial groups. PMID:22051089

  10. Exploratory study into the effect of abdominal mass loading on airways resistance and ventilatory failure

    PubMed Central

    Dattani, Raj S; Swerner, Casey B; Stradling, John R; Manuel, Ari RG

    2016-01-01

    Objective We hypothesised that the airway resistance during tidal breathing would correlate with a particular pattern of increasing obesity, particularly when supine, and would differ between participants with and without ventilatory failure. Methods In our cross-sectional cohort study, 72 morbidly obese patients (40 males, 32 females, mean body mass index (BMI) 47.2) had measurements of both airways resistance (by impulse oscillometry (IOS)) and adiposity (by dual-energy X-ray absorptiometry (DXA)). Results All measures of airways resistance increased in the supine position: total airways resistance (R5) +37% (p<0.0005); large airways resistance (R20) +29% (p<0.0005); and small airways resistance (R5–R20) +52% (p<0.0005). BMI was correlated with seated R5, seated R5–R20, supine R5 and supine R5–R20 (r=0.33 p<0.006, r=0.32 p<0.004, r=0.30 p<0.02 and r=0.36 p<0.04, respectively). Visceral adipose tissue mass was correlated with supine R5–20 (r=0.46 p<0.05). Supine measures of total airways resistance (R5) and large airways resistance (R20) differed between those with and without ventilatory failure, as did mean weight and BMI. Conclusions Our study identifies a potentially detrimental effect of the supine posture on tidal breathing airways resistance in obese patients. This change is correlated most with visceral adipose tissue mass and the small airways. We were able to demonstrate that supine increases in airways resistance during tidal breathing, within obese patients, are different between those with and without ventilatory failure. Trial registration number NCT01380418; pre-results. PMID:27335651

  11. Fetal and infant growth predict hip geometry at six years old: Findings from the Southampton Women’s Survey

    PubMed Central

    Harvey, Nicholas C; Cole, Zoe A; Crozier, Sarah R; Ntani, Georgia; Mahon, Pamela A; Robinson, Sian M; Inskip, Hazel M; Godfrey, Keith M; Dennison, Elaine M; Cooper, Cyrus

    2013-01-01

    Background We investigated relationships between early growth and proximal femoral geometry at age six years in a prospective population-based cohort, the Southampton Women’s Survey. Methods In 493 mother-offspring pairs we assessed linear size (individual measure dependent on developmental stage) using high-resolution ultrasound at 11, 19 and 34 weeks gestation (femur length) and at birth, 1, 2, 3, 4 and 6 years (crown-heel length/height). Standard deviation (SD)-scores were created and conditional regression modelling generated mutually independent growth variables. Children underwent hip DXA (Dual X-ray absorptiometry) at 6 years (Hologic Discovery, Hologic Inc., MA); hip structure analysis software yielded measures of geometry and strength. Results There were strong associations between early linear growth and femoral neck section modulus (Z) at 6 years, with the strongest relationships observed for femur growth from 19-34 weeks gestation (β=0.26 cm3/SD, p<0.0001), and for height growth from birth to 1 year (β=0.25 cm3/SD, p<0.0001) and 1-2 years (β=0.33 cm3/SD, p<0.0001), with progressively weaker relationships over years 3 (β=0.23 cm3/SD, p=0.0002) and 4 (β=0.10 cm3/SD, p=0.18). Conclusions These results demonstrate that growth before age 3 years predicts proximal femoral geometry at six years old. The data suggest critical periods in which there is capacity for long term influence on the later skeletal growth trajectory. PMID:23857297

  12. Seven years of follow up of trabecular bone score, bone mineral density, body composition and quality of life in adults with growth hormone deficiency treated with rhGH replacement in a single center

    PubMed Central

    Allo Miguel, Gonzalo; Serraclara Plá, Alicia; Partida Muñoz, Myriam Lorena; Martínez Díaz-Guerra, Guillermo; Hawkins, Federico

    2016-01-01

    Background: Adult growth hormone deficiency (AGHD) is characterized by impaired physical activity, diminished quality of life (QoL), weight and fat mass gain, decreased muscle mass and decreased bone mineral density (BMD). The aim of this study was to evaluate the effects of long-term treatment (7 years) with recombinant human growth hormone (rhGH) on metabolic parameters, body composition (BC), BMD, bone microarchitecture and QoL. Patients and Methods: In this prospective study, BMD and BC were assessed by dual-energy X-ray absorptiometry (DXA). Bone microarchitecture was assessed with the trabecular bone score (TBS). The QoL-AGHDA test was used to assess QoL. Results: A total of 18 AGHD patients (mean age, 37.39 ± 12.42) were included. Body weight and body mass index (BMI) showed a significant increase after 7 years (p = 0.03 and p = 0.001, respectively). There was a significant tendency of body fat mass (BFM) (p = 0.028) and lean body mass (LBM) (p = 0.005) to increase during the 7 years of rhGH treatment. There was a significant increase in lumbar spine (LS) BMD (p = 0.01). TBS showed a nonsignificant decrease after 7 years of treatment, with a change of -0.86% ± 1.95. QoL showed a large and significant improvement (p = 0.02). Conclusion: Long-term rhGH treatment in AGHD patients induces a large and sustained improvement in QoL. Metabolic effects are variable with an increase in LBM as well as in BMI and BFM. There is a positive effect on BMD based on the increase in LS BMD, which stabilizes during long-term therapy and is not associated with a similar increase in bone microarchitecture. PMID:27293538

  13. Weight and Lean Body Mass Change with Antiretroviral Initiation and Impact on Bone Mineral Density: AIDS Clinical Trials Group Study A5224s

    PubMed Central

    Erlandson, Kristine Mace; Kitch, Douglas; Tierney, Camlin; Sax, Paul E.; Daar, Eric S.; Tebas, Pablo; Melbourne, Kathleen; Ha, Belinda; Jahed, Nasreen C.; Mccomsey, Grace A.

    2014-01-01

    Objective To compare the effect initiating different antiretroviral therapy (ART) regimens have on weight, body mass index (BMI), and lean body mass (LBM) and explore how changes in body composition are associated with bone mineral density (BMD). Methods A5224s was a substudy of A5202, a prospective trial of 1857 ART-naïve participants randomized to blinded abacavir-lamivudine (ABC/3TC) or tenofovir DF-emtricitabine (TDF/FTC) with open-label efavirenz (EFV) or atazanavir-ritonavir (ATV/r). All subjects underwent dual-energy absorptiometry (DXA) and abdominal CT for body composition. Analyses used 2-sample t-tests and linear regression. Results A5224s included 269 subjects: 85% male, 47% white non-Hispanic, median age 38 years, HIV-1 RNA 4.6 log10 copies/mL, and CD4 233 cells/µL. Overall, significant gains occurred in weight, BMI, and LBM at 96 weeks post randomization (all p<0.001). Assignment to ATV/r (vs EFV) resulted in significantly greater weight (mean difference 3.35 kg) and BMI gain (0.88 kg/m2; both p=0.02), but not LBM (0.67 kg; p=0.15), while ABC/3TC and TDF/FTC were not significantly different (p≥0.10). In multivariable analysis, only lower baseline CD4 count and higher HIV-1 RNA were associated with greater increase in weight, BMI, or LBM. In multivariable analyses, increased LBM was associated with an increased hip BMD. Conclusions ABC/3TC vs. TDF/FTC did not differ in change in weight, BMI, or LBM; ATV/r vs. EFV resulted in greater weight and BMI gain but not LBM. A positive association between increased LBM and increased hip BMD should be further investigated through prospective interventional studies to verify the impact of increased LBM on hip BMD. PMID:24384588

  14. Reference Values of Skeletal Muscle Mass for Korean Children and Adolescents Using Data from the Korean National Health and Nutrition Examination Survey 2009-2011

    PubMed Central

    Kim, Eun Young

    2016-01-01

    Background Skeletal muscle mass (SMM) plays a crucial role in systemic glucose metabolism. Objective To obtain reference data on absolute and relative values of SMM for Korean children and adolescents. Methods Cross-sectional results from 1919 children and adolescents (1024 boys) aged 10–18 years that underwent dual-energy X-ray absorptiometry (DXA) during the Korean National Health and Nutrition Examination Survey 2009–2011 were analyzed. SMMs were evaluated as follows; absolute SMM (appendicular skeletal muscle mass [ASM]) and relative SMMs, namely, height-adjusted skeletal muscle index (SMI; ASM/height2), %SMM (ASM/weight x 100), and skeletal muscle-to-body fat ratio (MFR; ASM/body fat mass). Results Percentile curves illustrated the developmental patterns of the SMMs of Korean children and adolescents. ASM and SMI increased with age in both genders, and increased from age 10 throughout adolescence in boys, whereas in girls, they increased until age 13 and then stabilized. In boys, %SMM and MFR were highest at age 15 and then slowly stabilized or decreased, whereas in girls, they peaked at age 10 to 11 and then decreased through adolescence. Cut-off values for low MFR were identified and a significant association was found between a low MFR and high risk of metabolic syndrome. However, this association was found to be dependent on gender and the level of BMI. Conclusion This study provides reference values of absolute and relative SMM for Korean children and adolescents. Detailed body composition analyses including skeletal muscle and fat mass might provide improved measures of metabolic risk. PMID:27073844

  15. Intra-abdominal fat is related to metabolic syndrome and non-alcoholic fat liver disease in obese youth

    PubMed Central

    2013-01-01

    Background Previous studies have shown an association between adiposity, especially intra-abdominal adipose tissue, and hemodynamic/metabolic comorbidities in adults, however it is not clear in pediatric population. The aim of the study was to analyze the relationship between non-alcoholic fatty liver disease (NAFLD) and components of metabolic syndrome (MS) with values of intra-abdominal (IAAT) and subcutaneous (SCAT) adipose tissue in obese children and adolescents. Methods Cross-sectional study. Subjects: 182 obese sedentary children and adolescents (aged 6 to 16 y), identified by the body mass index (BMI). Measurements: Body composition and trunk fat by dual-energy X-ray absorptiometry- DXA; lipid profile, blood pressure and pubertal stage were also assessed. NAFLD was classified as absent (0), mild (1), moderate (2) and severe (3), and intra-abdominal and subcutaneous abdominal fat thickness were identified by ultrasound. The MS was identified according to the cut offs proposed by World Health Organization adapted for children and adolescents. The chi-square test was used to compare categorical variables, and the binary logistic regression indicated the magnitude of the associations adjusted by potential cofounders (sex, age, maturation, NAFLD and HOMA-IR). Results Higher quartile of SCAT was associated with elevated blood pressure (p = 0.015), but not associated with NAFLD (p = 0.665). Higher IAAT was positively associated with increased dyslipidemia (p = 0.001), MS (p = 0.013) and NAFLD (p = 0.005). Intermediate (p = 0.007) and highest (p = 0.001) quartile of IAAT were also associated with dyslipidemia, independently of age, sex, maturation, NAFLD and HOMA-IR (homeostatic model assessment-insulin resistance). Conclusion Obese children and adolescents, with higher IAAT are more prone to develop MS and NAFLD than those with higher values of SCAT, independent of possible confounding variables. PMID:23919592

  16. Bone Density in Patients with Cervical Cancer or Endometrial Cancer in comparison with Healthy Control; According to the stages

    PubMed Central

    Lee, Yubin; Kim, Ari; Kim, Heung Yeol; Eo, Wan Kyu; Lee, Eun Sil; Chun, Sungwook

    2015-01-01

    Objective: To evaluate the bone mineral density (BMD) in the lumbar spine and femur in postmenopausal women with cervical cancer and endometrial cancer without bone metastasis in comparison with that in healthy control postmenopausal women, and to assess the loss of BMD according to the cancer stage. Materials and methods: We analyzed the BMD of the lumbar spine and femur using dual-energy X-ray absorptiometry (DXA) in 218 patients with cervical cancer, 85 patients with endometrial cancer, and 259 healthy controls. The serum levels of calcium (Ca), phosphorus (P), osteocalcin (OSC), and total alkaline phosphatase (ALP), and urine deoxypyridinoline(DPL) were measured in all participants. Results: Age, body mass index, parity, and time since menopause were not significantly different between the three groups. Serum Ca level was higher in the cervical cancer group (p = 0.000), however, urine DPL was lower in endometrial cancer group (p = 0.000). The T-scores of basal BMD at the second and fourth lumbar vertebra (L2, L4) were significantly lower in patients with cervical cancer (p = 0.038, 0.000, respectively) compared to those in the healthy control groups. Additionally, the incidence of osteoporosis and osteopenia basal status of bone mass was significantly higher in patients with cervical cancer compared to that in controls (p = 0.016). No differences in basal BMD of the lumbar spine and femur were observed between patients with cervical cancer according to their stages. Conclusion: Our results suggest that postmenopausal women with cervical cancer have a lower BMD and are at increased risk of osteoporosis in the lumbar spine before receiving anticancer treatment compared with postmenopausal women with endometrial cancer. PMID:26185529

  17. Periprosthetic tibial bone mineral density changes after total knee arthroplasty.

    PubMed

    Jaroma, Antti; Soininvaara, Tarja; Kröger, Heikki

    2016-06-01

    Background and purpose - Total knee arthroplasty (TKA) may cause postoperative periprosthetic bone loss due to stress shielding. Bone also adapts to mechanical alterations such as correction of malalignment. We investigated medium-term changes in bone mineral density (BMD) in tibial periprosthetic bone after TKA. Patients and methods - 86 TKA patients were prospectively measured with dual-energy X-ray absorptiometry (DXA), the baseline measurement being within 1 week after TKA and the follow-up measurements being at 3 and 6 months, and at 1, 2, 4, and 7 years postoperatively. Long standing radiographs were taken and clinical evaluation was done with the American Knee Society (AKS) score. Results - The baseline BMD of the medial tibial metaphyseal region of interest (ROI) was higher in the varus aligned knees (25%; p < 0.001). Medial metaphyseal BMD decreased in subjects with preoperatively varus aligned knees (13%, p < 0.001) and in those with preoperatively valgus aligned knees (12%, p = 0.02) between the baseline and 7-year measurements. No statistically significant changes in BMD were detected in lateral metaphyseal ROIs. No implant failures or revision surgery due to tibial problems occurred. Interpretation - Tibial metaphyseal periprosthetic bone is remodeled after TKA due to mechanical axis correction, resulting in more balanced bone stock below the tibial tray. The diaphyseal BMD remains unchanged after the initial drop, within 3-6 months. This remodeling process was related to good component survival, as there were no implant failures or revision operations due to tibial problems in this medium-term follow-up. PMID:27120266

  18. Association of sarcopenia and physical activity with femur bone mineral density in elderly women

    PubMed Central

    Lee, Inhwan; Ha, Changduk; Kang, Hyunsik

    2016-01-01

    [Purpose] This study examined the association of femur bone mineral density (BMD) with body composition and physical activity in elderly women. [Methods] This was a cross sectional study involving 119 women with mean age of 73.1±5.5 years. Body composition parameters including body mass index (BMI), percent of body fat (%BF), appendicular skeletal muscle mass (ASM) index and femur BMD was measured by dual-energy X-ray absorptiometry (DXA). Physical activity was assessed by the uniaxial accelerometer for 7 consecutive days including weekends. Based on femur BMD T-scores, subjects were classified as optimal group, osteopenia group, and osteoporosis group. Based on ASM index, subjects were classified as normal group and sarcopenia group. According to WHO recommendations of physical activity for elderly, the subjects were classified as active group or inactive group. Logistic regression analyses were used to determine the odds ratio (OR) for osteopenia and osteoporosis. [Results] There were linear decreases for body composition parameters including weight (P=.023), BMI (P=.039), lean mass (P=.032), ASM index (P=.007) and physical activity parameters including daily of step (P<.001), low intensity physical activity (P<.001), moderate intensity physical activity (P=.001) across femur BMD levels. Compared to the normal group (OR=1), the sarcopenia group had a significantly higher OR (OR=4.823; P=.042), and the inactive group had a significantly higher OR (OR=5.478; P=.005) having osteopenia and osteoporosis when compared to the active group (OR=1). [Conclusion] The findings of this study suggested that physical activity along with a healthy nutrition should be promoted as a preventive strategy against osteopenia and osteoporosis in elderly women. PMID:27298809

  19. Panoramic-Based Mandibular Indices and Bone Mineral Density of Femoral Neck and Lumbar Vertebrae in Women

    PubMed Central

    Marandi, S.; Bagherpour, A.; Imanimoghaddam, M.; Hatef, MR.; Haghighi, AR.

    2010-01-01

    Objective: The aim of this cross-sectional analytic study was to evaluate the diagnostic efficacy of panoramic-based indices of the mandible (Mental Index-MI, Mandibular Cortical Index-MCI and Panoramic Mandibular Index-PMI) and to determine their correlation with bone mineral density (BMD) of the femoral neck and lumbar vertebrae (L2-L4) in order to assess the possibility of using these parameters as indicators of osteoporosis. Materials and Methods: The mandibular indices of 67 women over 35 years old were measured from panoramic radiographs, and bone densitometry was performed in the femoral neck and lumbar vertebrae (L2-L4), using DXA (Dual Energy X-ray Absorptiometry) technique. The patients were divided into three categories of normal, osteopenic and osteoporotic in each skeletal region. One-way ANOVA and ROC curve analyses were applied. The results were considered statistically significant when the P-value was less than 0.05. Results: Comparing the mean BMD in the femoral neck in women between C1 and C3 subgroups of MCI, a significant difference was detected (P=0.04). The mean PMI in the three skeletal subgroups was not different according to the skeletal region (P>0.05). We found a significant difference in mean MI between normal and osteopenic subgroups in the femoral neck (P=0.042). Conclusion: Using radiomorphometric indices of the mandible (MCI-MI) may be useful in determining the skeletal status of the patients, but is not sufficient for precise evaluation. PMID:21998782

  20. Collagen type-I leads to in vivo matrix mineralization and secondary stabilization of Mg-Zr-Ca alloy implants.

    PubMed

    Mushahary, Dolly; Wen, Cuie; Kumar, Jerald Mahesh; Lin, Jixing; Harishankar, Nemani; Hodgson, Peter; Pande, Gopal; Li, Yuncang

    2014-10-01

    Biodegradable magnesium-zirconia-calcium (Mg-Zr-Ca) alloy implants were coated with Collagen type-I (Coll-I) and assessed for their rate and efficacy of bone mineralization and implant stabilization. The phases, microstructure and mechanical properties of these alloys were analyzed using X-ray diffraction (XRD), optical microscopy and compression test, respectively, and the corrosion behavior was established by their hydrogen production rate in simulated body fluid (SBF). Coll-I extracted from rat tail, and characterized using fourier transform infrared (FT-IR) spectroscopy, was used for dip-coating the Mg-based alloys. The coated alloys were implanted into the femur bones of male New Zealand white rabbits. In vivo bone formation around the implants was quantified by measuring the bone mineral content/density (BMC/BMD) using dual-energy X-ray absorptiometry (DXA). Osseointegration of the implant and new bone mineralization was visualized by histological and immunohistochemical analysis. Upon surface coating with Coll-I, these alloys demonstrated high surface energy showing enhanced performance as an implant material that is suitable for rapid and efficient new bone tissue induction with optimal mineral content and cellular properties. The results demonstrate that Coll-I coated Mg-Zr-Ca alloys have a tendency to form superior trabecular bone structure with better osteoinduction around the implants and higher implant secondary stabilization, through the phenomenon of contact osteogenesis, compared to the control and uncoated ones in shorter periods of implantation. Hence, Coll-I surface coating of Mg-Zr-Ca alloys is a promising method for expediting new bone formation in vivo and enhancing osseointegration in load bearing implant applications. PMID:25179112

  1. Trabecular bone score in healthy ageing

    PubMed Central

    Bazzocchi, A; Ponti, F; Diano, D; Amadori, M; Albisinni, U; Battista, G

    2015-01-01

    Objective: The main aim of this work was to report on trabecular bone score (TBS) by dual-energy X-ray absorptiometry (DXA) of healthy Italian subjects to be used as a reference standard for future study in clinical and research settings. The secondary aim was to investigate the link between TBS and conventional parameters of bone and body composition by DXA. Methods: 250 individuals of 5 age bands (spanning from 18 to 70 years of age, equally distributed for both age and sex) were prospectively recruited. A lumbar spine (LS) DXA scan (Lunar iDXA™; GE Healthcare, Madison, WI) was acquired for each subject and then analysed with the latest version of TBS iNsight v. 2.1 (Med-Imaps, Pessac, France) software. LS bone mineral density (LS BMD), Z-score, T-score and TBS values were collected. Pearson's test was used to investigate the correlations between TBS and LS BMD and the influence of age, body mass index (BMI) and body composition on these parameters. Results: A significant decrease of TBS and LS BMD was observed with ageing in both males (TBS mean values from 1.486 to 1.374; LS BMD mean values from 1.219 to 1.187) and females (TBS mean values from 1.464 to 1.306; LS BMD mean values from 1.154 to 1.116). No statistically significant difference was achieved among males and females of the same age group for both TBS and LS BMD, with the exception of the fifth age group. A significant correlation was found between LS BMD and TBS values in both sexes (r  = 0.555–0.655, p < 0.0001). BMI influenced LS BMD but not TBS. TBS values were inversely correlated with some fat mass parameters, in particular with visceral adipose tissue (in males: r = −0.332, p < 0.001; in females: r = −0.348, p < 0.0001). No significant correlation was found between TBS and total lean mass, opposite to LS BMD (in males: r = 0.418; p < 0.0001; in females: r = −0.235; p < 0.001). Conclusion: This report is an attempt to start building a database for

  2. Normative Data for Bone Mass in Healthy Term Infants from Birth to 1 Year of Age

    PubMed Central

    Gallo, Sina; Vanstone, Catherine A.; Weiler, Hope A.

    2012-01-01

    For over 2 decades, dual-energy X-ray absorptiometry (DXA) has been the gold standard for estimating bone mineral density (BMD) and facture risk in adults. More recently DXA has been used to evaluate BMD in pediatrics. However, BMD is usually assessed against reference data for which none currently exists in infancy. A prospective study was conducted to assess bone mass of term infants (37 to 42 weeks of gestation), weight appropriate for gestational age, and born to healthy mothers. The group consisted of 33 boys and 26 girls recruited from the Winnipeg Health Sciences Center (Manitoba, Canada). Whole body (WB) as well as regional sites of the lumbar spine (LS 1–4) and femur was measured using DXA (QDR 4500A, Hologic Inc.) providing bone mineral content (BMC) for all sites and BMD for spine. During the year, WB BMC increased by 200% (76.0 ± 14.2 versus 227.0 ± 29.7 g), spine BMC by 130% (2.35 ± 0.42 versus 5.37 ± 1.02 g), and femur BMC by 190% (2.94 ± 0.54 versus 8.50 ± 1.84 g). Spine BMD increased by 14% (0.266 ± 0.044 versus 0.304 ± 0.044 g/cm2) during the year. This data, representing the accretion of bone mass during the first year of life, is based on a representative sample of infants and will aid in the interpretation of diagnostic DXA scans by researchers and health professionals. PMID:23091773

  3. Prevalent Morphometric Vertebral Fractures in Professional Male Rugby Players

    PubMed Central

    Hind, Karen; Birrell, Fraser; Beck, Belinda

    2014-01-01

    There is an ongoing concern about the risk of injury to the spine in professional rugby players. The objective of this study was to investigate the prevalence of vertebral fracture using vertebral fracture assessment (VFA) dual energy X-ray absorptiometry (DXA) imaging in professional male rugby players. Ninety five professional rugby league (n = 52) and union (n = 43) players (n = 95; age 25.9 (SD 4.3) years; BMI: 29.5 (SD 2.9) kg.m2) participated in the research. Each participant received one VFA, and one total body and lumbar spine DXA scan (GE Lunar iDXA). One hundred and twenty vertebral fractures were identified in over half of the sample by VFA. Seventy four were graded mild (grade 1), 40 moderate (grade 2) and 6 severe (grade 3). Multiple vertebral fractures (≥2) were found in 37 players (39%). There were no differences in prevalence between codes, or between forwards and backs (both 1.2 v 1.4; p>0.05). The most common sites of fracture were T8 (n = 23), T9 (n = 18) and T10 (n = 21). The mean (SD) lumbar spine bone mineral density Z-score was 2.7 (1.3) indicating high player bone mass in comparison with age- and sex-matched norms. We observed a high number of vertebral fractures using DXA VFA in professional rugby players of both codes. The incidence, aetiology and consequences of vertebral fractures in professional rugby players are unclear, and warrant timely, prospective investigation. PMID:24846310

  4. Elevated Circulating Sclerostin Concentrations in Individuals With High Bone Mass, With and Without LRP5 Mutations

    PubMed Central

    Poole, Kenneth E. S.; McCloskey, Eugene V.; Duncan, Emma L.; Rittweger, Jörn; Fraser, William D.; Smith, George Davey; Tobias, Jonathan H.

    2014-01-01

    Context: The role and importance of circulating sclerostin is poorly understood. High bone mass (HBM) caused by activating LRP5 mutations has been reported to be associated with increased plasma sclerostin concentrations; whether the same applies to HBM due to other causes is unknown. Objective: Our objective was to determine circulating sclerostin concentrations in HBM. Design and Participants: In this case-control study, 406 HBM index cases were identified by screening dual-energy x-ray absorptiometry (DXA) databases from 4 United Kingdom centers (n = 219 088), excluding significant osteoarthritis/artifact. Controls comprised unaffected relatives and spouses. Main measures: Plasma sclerostin; lumbar spine L1, total hip, and total body DXA; and radial and tibial peripheral quantitative computed tomography (subgroup only) were evaluated. Results: Sclerostin concentrations were significantly higher in both LRP5 HBM and non-LRP5 HBM cases compared with controls: mean (SD) 130.1 (61.7) and 88.0 (39.3) vs 66.4 (32.3) pmol/L (both P < .001, which persisted after adjustment for a priori confounders). In combined adjusted analyses of cases and controls, sclerostin concentrations were positively related to all bone parameters found to be increased in HBM cases (ie, L1, total hip, and total body DXA bone mineral density and radial/tibial cortical area, cortical bone mineral density, and trabecular density). Although these relationships were broadly equivalent in HBM cases and controls, there was some evidence that associations between sclerostin and trabecular phenotypes were stronger in HBM cases, particularly for radial trabecular density (interaction P < .01). Conclusions: Circulating plasma sclerostin concentrations are increased in both LRP5 and non-LRP5 HBM compared with controls. In addition to the general positive relationship between sclerostin and DXA/peripheral quantitative computed tomography parameters, genetic factors predisposing to HBM may contribute to

  5. From Method to Post Method: A Panacea!

    ERIC Educational Resources Information Center

    Masouleh, Nima Shakouri

    2012-01-01

    The foundation of language teaching has undergone many changes. The rise and fall of language teaching methods depends upon a variety of factors extrinsic to a method itself and often reflects the influence of profit-seekers and promoters, as well as the forces of the intellectual marketplace. There was always a source of contention among people…

  6. The Multidimensional WKB Method.

    ERIC Educational Resources Information Center

    Knudson, Stephen K.; Noid, D. W.

    1989-01-01

    Discusses a new method for determining the eigenvalues of the Schroedinger equation when the potential energy function does not have a simple form. Describes the mathematical methods and provides an application. Lists limitations to the method. (MVL)

  7. Uranium price forecasting methods

    SciTech Connect

    Fuller, D.M.

    1994-03-01

    This article reviews a number of forecasting methods that have been applied to uranium prices and compares their relative strengths and weaknesses. The methods reviewed are: (1) judgemental methods, (2) technical analysis, (3) time-series methods, (4) fundamental analysis, and (5) econometric methods. Historically, none of these methods has performed very well, but a well-thought-out model is still useful as a basis from which to adjust to new circumstances and try again.

  8. The Moore Method

    ERIC Educational Resources Information Center

    Jones, F. Burton

    1977-01-01

    The Moore methods, in which college mathematics students prove theorems for themselves, is described. Difficulties and drawbacks to this method, appropriate areas of mathematics in which the Moore method can be used, and techniques in using the method are discussed. (DT)

  9. Designing ROW Methods

    NASA Technical Reports Server (NTRS)

    Freed, Alan D.

    1996-01-01

    There are many aspects to consider when designing a Rosenbrock-Wanner-Wolfbrandt (ROW) method for the numerical integration of ordinary differential equations (ODE's) solving initial value problems (IVP's). The process can be simplified by constructing ROW methods around good Runge-Kutta (RK) methods. The formulation of a new, simple, embedded, third-order, ROW method demonstrates this design approach.

  10. Failure combination method

    SciTech Connect

    Hedin, F.; Le Coguiec, A.; Le Floch, C.; Llory, M.; Villemeur, A.

    1981-01-01

    The method described in this paper is an inductive method for combining failures (called the Failure Combination Method (FCM)). It is based on a preliminary analysis of the systems performed with an FMEA. As a study has been undertaken to test the method, the organization of the study as well as its first results from a methodological point of view are stressed. 8 refs.

  11. Radiochemical method development

    SciTech Connect

    Erickson, M.D.; Aldstadt, J.H.; Alvarado, J.S.; Crain, J.S.; Orlandini, K.A.; Smith, L.L.

    1994-09-01

    The authors have developed methods for chemical characterization of the environment under a multitask project that focuses on improvement of radioanalytical methods with an emphasis on faster and cheaper routine methods. The authors have developed improved methods for separation of environmental levels of technetium-99, radium, and actinides from soil and water; separation of actinides from soil and water matrix interferences; and isolation of strontium. They are also developing methods for simultaneous detection of multiple isotopes (including nonradionuclides) by using a new instrumental technique, inductively coupled plasma-mass spectrometry (ICP-MS). The new ICP-MS methods have greater sensitivity and efficiency and could replace many radiometric techniques. They are using flow injection analysis to integrate and automate the separation methods with the ICP-MS methodology. The final product of all activities will be methods that are available (published in the U.S. Department of Energy`s analytical methods compendium) and acceptable for use in regulatory situations.

  12. Methods and application of bone densitometry in clinical diagnosis

    SciTech Connect

    Wahner, H.W.; Riggs, B.L.

    1986-01-01

    With the awareness of osteoporosis as a major health problem for an aging population, there is great interest in early recognition and treatment of abnormal bone loss. Effective prevention of bone loss has to occur prior to the occurrence of irreparable damage. Standard radiographic procedures are not sensitive enough for the task. Therefore, a number of alternative procedures to estimate bone loss have been developed over the years, ranging from efforts to quantitate information obtained from radiographic images to sophisticated procedures such as neutron activation analysis or procedures based on the Compton scatter phenomenon. Only two procedures, photon absorptiometry and computed tomography (CT), have emerged as applicable for routine clinical use. In photon absorptiometry the entire bone mineral (cortical and trabecular bone) of a specific skeletal site is measured. CT allows measuring of bone mineral of trabecular or cortical bone alone. Normally, bone mass reaches a maximum in the third decade and then continuously declines. This age-related bone loss is greater in women in whom an accelerated rate of loss occurs at the menopause. When bone density reaches a critical fracture threshold, skeletal fractures occur (spine, hip, and distal long bones). The age at which this critical fracture threshold is reached depends on the maximal bone mass achieved in early adulthood and the rate of loss with increasing age. With the exception of NaF, present-day therapeutic efforts only retard or prevent bone loss but do not significantly add bone mineral to the skeleton. Recognition of high-risk groups and early treatment are therefore required. 79 references.

  13. Selecting Needs Analysis Methods.

    ERIC Educational Resources Information Center

    Newstrom, John W.; Lilyquist, John M.

    1979-01-01

    Presents a contingency model for decision making with regard to needs analysis methods. Focus is on 12 methods with brief discussion of their defining characteristics and some operational guidelines for their use. (JOW)

  14. Electromagnetic induction methods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Electromagnetic induction geophysical methods are finding greater and greater use for agricultural purposes. Electromagnetic induction methods measure the electrical conductivity (or resistivity) for a bulk volume of soil directly beneath the surface. An instrument called a ground conductivity meter...

  15. Geobacteraceae strains and methods

    DOEpatents

    Lovley, Derek R.; Nevin, Kelly P.; Yi, Hana

    2015-07-07

    Embodiments of the present invention provide a method of producing genetically modified strains of electricigenic microbes that are specifically adapted for the production of electrical current in microbial fuel cells, as well as strains produced by such methods and fuel cells using such strains. In preferred embodiments, the present invention provides genetically modified strains of Geobacter sulfurreducens and methods of using such strains.

  16. Space methods in oceanology

    NASA Technical Reports Server (NTRS)

    Bolshakov, A. A.

    1985-01-01

    The study of Earth from space with specialized satellites, and from manned orbiting stations, has become important in the space programs. The broad complex of methods used for probing Earth from space are different methods of the study of ocean, dynamics. The different methods of ocean observation are described.

  17. Equations and closure methods

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Basic differential equations governing compressible turbulent boundary layer flow are reviewed, including conservation of mass and energy, momentum equations derived from Navier-Stokes equations, and equations of state. Closure procedures were broken down into: (1) simple or zeroth-order methods, (2) first-order or mean field closure methods, and (3) second-order or mean turbulence field methods.

  18. Methods in human cytogenetics

    SciTech Connect

    1993-12-31

    Chapter 4, discusses the various techniques used in the study human cytogenetics. The methods are discussed in historical order, from direct methods to tissue culture techniques, prenatal studies, meiotic studies, sex chromatin techniques, banding techniques, prophase banding and replication studies. Nomenclature of human chromosomes and quantitative methods are also mentioned. 60 refs., 3 figs.

  19. Redefining the "Scientific Method".

    ERIC Educational Resources Information Center

    Spiece, Kelly R.; Colosi, Joseph

    2000-01-01

    Surveys 15 introductory biology textbooks for their presentation of the scientific method. Teaching the scientific method involves more than simplified steps and subjectivity--human politics, cultural influences, and chance are all a part of science. Presents an activity for students to experience the scientific method. (Contains 34 references.)…

  20. Accelerated molecular dynamics methods

    SciTech Connect

    Perez, Danny

    2011-01-04

    The molecular dynamics method, although extremely powerful for materials simulations, is limited to times scales of roughly one microsecond or less. On longer time scales, dynamical evolution typically consists of infrequent events, which are usually activated processes. This course is focused on understanding infrequent-event dynamics, on methods for characterizing infrequent-event mechanisms and rate constants, and on methods for simulating long time scales in infrequent-event systems, emphasizing the recently developed accelerated molecular dynamics methods (hyperdynamics, parallel replica dynamics, and temperature accelerated dynamics). Some familiarity with basic statistical mechanics and molecular dynamics methods will be assumed.

  1. An extended Lagrangian method

    NASA Technical Reports Server (NTRS)

    Liou, Meng-Sing

    1992-01-01

    A unique formulation of describing fluid motion is presented. The method, referred to as 'extended Lagrangian method', is interesting from both theoretical and numerical points of view. The formulation offers accuracy in numerical solution by avoiding numerical diffusion resulting from mixing of fluxes in the Eulerian description. Meanwhile, it also avoids the inaccuracy incurred due to geometry and variable interpolations used by the previous Lagrangian methods. Unlike the Lagrangian method previously imposed which is valid only for supersonic flows, the present method is general and capable of treating subsonic flows as well as supersonic flows. The method proposed in this paper is robust and stable. It automatically adapts to flow features without resorting to clustering, thereby maintaining rather uniform grid spacing throughout and large time step. Moreover, the method is shown to resolve multi-dimensional discontinuities with a high level of accuracy, similar to that found in one-dimensional problems.

  2. Study Protocol - Accurate assessment of kidney function in Indigenous Australians: aims and methods of the eGFR Study

    PubMed Central

    2010-01-01

    Background There is an overwhelming burden of cardiovascular disease, type 2 diabetes and chronic kidney disease among Indigenous Australians. In this high risk population, it is vital that we are able to measure accurately kidney function. Glomerular filtration rate is the best overall marker of kidney function. However, differences in body build and body composition between Indigenous and non-Indigenous Australians suggest that creatinine-based estimates of glomerular filtration rate derived for European populations may not be appropriate for Indigenous Australians. The burden of kidney disease is borne disproportionately by Indigenous Australians in central and northern Australia, and there is significant heterogeneity in body build and composition within and amongst these groups. This heterogeneity might differentially affect the accuracy of estimation of glomerular filtration rate between different Indigenous groups. By assessing kidney function in Indigenous Australians from Northern Queensland, Northern Territory and Western Australia, we aim to determine a validated and practical measure of glomerular filtration rate suitable for use in all Indigenous Australians. Methods/Design A cross-sectional study of Indigenous Australian adults (target n = 600, 50% male) across 4 sites: Top End, Northern Territory; Central Australia; Far North Queensland and Western Australia. The reference measure of glomerular filtration rate was the plasma disappearance rate of iohexol over 4 hours. We will compare the accuracy of the following glomerular filtration rate measures with the reference measure: Modification of Diet in Renal Disease 4-variable formula, Chronic Kidney Disease Epidemiology Collaboration equation, Cockcroft-Gault formula and cystatin C- derived estimates. Detailed assessment of body build and composition was performed using anthropometric measurements, skinfold thicknesses, bioelectrical impedance and a sub-study used dual-energy X-ray absorptiometry. A

  3. Total body bone mineral density in young children: influence of head bone mineral density.

    PubMed

    Taylor, A; Konrad, P T; Norman, M E; Harcke, H T

    1997-04-01

    Dual-energy X-ray absorptiometry (DXA) with its short scan time, low radiation dose, and high precision and accuracy have made this technique particularly suitable for measuring total body bone mineral density (TBMD) in children. Other published reports have related TBMD to age in children 2-18 years of age. However, in young normal children aged 2-9 years (51 girls, 43 boys), we found that regression equations for TBMD with age as the predictor did not explain enough of the variance to warrant their use for predicting TBMD (adjusted R2 0.47, females; 0.41, males). Subtotal BMD (TBMD-head BMD) is predicted better by age because of a possibly invalid adult algorithm for head BMD (adjusted R2 0.73, females; 0.71, males). PMID:9101377

  4. [Medical Equipment Maintenance Methods].

    PubMed

    Liu, Hongbin

    2015-09-01

    Due to the high technology and the complexity of medical equipment, as well as to the safety and effectiveness, it determines the high requirements of the medical equipment maintenance work. This paper introduces some basic methods of medical instrument maintenance, including fault tree analysis, node method and exclusive method which are the three important methods in the medical equipment maintenance, through using these three methods for the instruments that have circuit drawings, hardware breakdown maintenance can be done easily. And this paper introduces the processing methods of some special fault conditions, in order to reduce little detours in meeting the same problems. Learning is very important for stuff just engaged in this area. PMID:26904890

  5. An extended Lagrangian method

    NASA Technical Reports Server (NTRS)

    Liou, Meng-Sing

    1993-01-01

    A unique formulation of describing fluid motion is presented. The method, referred to as 'extended Lagrangian method', is interesting from both theoretical and numerical points of view. The formulation offers accuracy in numerical solution by avoiding numerical diffusion resulting from mixing of fluxes in the Eulerian description. Meanwhile, it also avoids the inaccuracy incurred due to geometry and variable interpolations used by the previous Lagrangian methods. The present method is general and capable of treating subsonic flows as well as supersonic flows. The method proposed in this paper is robust and stable. It automatically adapts to flow features without resorting to clustering, thereby maintaining rather uniform grid spacing throughout and large time step. Moreover, the method is shown to resolve multidimensional discontinuities with a high level of accuracy, similar to that found in 1D problems.

  6. Texture analysis of X-ray radiographs is a more reliable descriptor of bone loss than mineral content in a rat model of localized disuse induced by the Clostridium botulinum toxin.

    PubMed

    Chappard, D; Chennebault, A; Moreau, M; Legrand, E; Audran, M; Basle, M F

    2001-01-01

    Botulism is a generalized paralyzing disease caused by the toxin of Clostridium botulinum (BTX). The toxin acts 3-4 days after injection by blocking the release of acetylcholine to the muscle. Six Wistar rats received a 2-U injection of BTX in the right quadriceps. Six rats were similarly injected with saline and were used as control. Paralysis of the quadriceps was obtained 4-5 days after the injection. Animals were killed 4 weeks after the BTX injection. The bone mineral content (BMC) was measured by dual-energy X-ray absorptiometry (DXA) on the femur and tibia. No side-to-side difference was observed for BMC on the whole tibia and femur in the BTX group. When subregions were selected in the bones, a significant decrease in BMC was obtained on the proximal tibia (-17.4 +/- 2.5%, p < 0.02). No significant difference could be observed on the proximal or distal femur, nor on the diaphyseal shafts. Numeric X-rays were done and a region of interest was transferred to an image analyzer. The texture of the trabecular bone was analyzed by the run length and fractal methods (skyscrapers and blanket). Significant differences were obtained on the proximal tibia for all methods except with fractal skyscrapers. On the distal femur, significant differences were obtained with the run length method, and the skyscrapers and the blanket method in the vertical direction. No differences were obtained with any method on the tibia and femur from control animals. Bone is a highly anisotropic material and its architecture at the microscopic level is conditioned by strains. The trabecular pattern differs in the proximal tibia than in the distal femural. Depending on the trabecular anisotropy, the algorithms can be more or less pertinent. BTX induced a significant bone loss on the bony subparts that are directly influenced by disuse. Texture analysis of X-ray images can reveal differences that were not evidenced by naked eyes. However, a combination of several methods appears necessary to

  7. New Dry Fractionation Methods

    NASA Technical Reports Server (NTRS)

    McKay, David S.; Cooper, Bonnie L.

    2010-01-01

    This slide presentation describes new fractionation methods that are used to create dust that is respirable for testing the effects of inhalation of lunar dust in preparation for future manned lunar exploration. Because lunar dust is a very limited commodity, a method that does not result in loss of the material had to be developed. The dust separation system that is described incorporates some traditional methods, while preventing the dust from being contaminated or changed in reactivity properties while also limiting losses.

  8. The Schwinger Variational Method

    NASA Technical Reports Server (NTRS)

    Huo, Winifred M.

    1995-01-01

    Variational methods have proven invaluable in theoretical physics and chemistry, both for bound state problems and for the study of collision phenomena. For collisional problems they can be grouped into two types: those based on the Schroedinger equation and those based on the Lippmann-Schwinger equation. The application of the Schwinger variational (SV) method to e-molecule collisions and photoionization has been reviewed previously. The present chapter discusses the implementation of the SV method as applied to e-molecule collisions.

  9. Methods of Voice Reconstruction

    PubMed Central

    Chen, Hung-Chi; Kim Evans, Karen F.; Salgado, Christopher J.; Mardini, Samir

    2010-01-01

    This article reviews methods of voice reconstruction. Nonsurgical methods of voice reconstruction include electrolarynx, pneumatic artificial larynx, and esophageal speech. Surgical methods of voice reconstruction include neoglottis, tracheoesophageal puncture, and prosthesis. Tracheoesophageal puncture can be performed in patients with pedicled flaps such as colon interposition, jejunum, or gastric pull-up or in free flaps such as perforator flaps, jejunum, and colon flaps. Other flaps for voice reconstruction include the ileocolon flap and jejunum. Laryngeal transplantation is also reviewed. PMID:22550443

  10. Spectral methods for CFD

    NASA Technical Reports Server (NTRS)

    Zang, Thomas A.; Streett, Craig L.; Hussaini, M. Yousuff

    1989-01-01

    One of the objectives of these notes is to provide a basic introduction to spectral methods with a particular emphasis on applications to computational fluid dynamics. Another objective is to summarize some of the most important developments in spectral methods in the last two years. The fundamentals of spectral methods for simple problems will be covered in depth, and the essential elements of several fluid dynamical applications will be sketched.

  11. Multigrid contact detection method

    NASA Astrophysics Data System (ADS)

    He, Kejing; Dong, Shoubin; Zhou, Zhaoyao

    2007-03-01

    Contact detection is a general problem of many physical simulations. This work presents a O(N) multigrid method for general contact detection problems (MGCD). The multigrid idea is integrated with contact detection problems. Both the time complexity and memory consumption of the MGCD are O(N) . Unlike other methods, whose efficiencies are influenced strongly by the object size distribution, the performance of MGCD is insensitive to the object size distribution. We compare the MGCD with the no binary search (NBS) method and the multilevel boxing method in three dimensions for both time complexity and memory consumption. For objects with similar size, the MGCD is as good as the NBS method, both of which outperform the multilevel boxing method regarding memory consumption. For objects with diverse size, the MGCD outperform both the NBS method and the multilevel boxing method. We use the MGCD to solve the contact detection problem for a granular simulation system based on the discrete element method. From this granular simulation, we get the density property of monosize packing and binary packing with size ratio equal to 10. The packing density for monosize particles is 0.636. For binary packing with size ratio equal to 10, when the number of small particles is 300 times as the number of big particles, the maximal packing density 0.824 is achieved.

  12. An Extended Lagrangian Method

    NASA Technical Reports Server (NTRS)

    Liou, Meng-Sing

    1995-01-01

    A unique formulation of describing fluid motion is presented. The method, referred to as 'extended Lagrangian method,' is interesting from both theoretical and numerical points of view. The formulation offers accuracy in numerical solution by avoiding numerical diffusion resulting from mixing of fluxes in the Eulerian description. The present method and the Arbitrary Lagrangian-Eulerian (ALE) method have a similarity in spirit-eliminating the cross-streamline numerical diffusion. For this purpose, we suggest a simple grid constraint condition and utilize an accurate discretization procedure. This grid constraint is only applied to the transverse cell face parallel to the local stream velocity, and hence our method for the steady state problems naturally reduces to the streamline-curvature method, without explicitly solving the steady stream-coordinate equations formulated a priori. Unlike the Lagrangian method proposed by Loh and Hui which is valid only for steady supersonic flows, the present method is general and capable of treating subsonic flows and supersonic flows as well as unsteady flows, simply by invoking in the same code an appropriate grid constraint suggested in this paper. The approach is found to be robust and stable. It automatically adapts to flow features without resorting to clustering, thereby maintaining rather uniform grid spacing throughout and large time step. Moreover, the method is shown to resolve multi-dimensional discontinuities with a high level of accuracy, similar to that found in one-dimensional problems.

  13. Cost-Effectiveness of Osteoporosis Screening Strategies for Men.

    PubMed

    Nayak, Smita; Greenspan, Susan L

    2016-06-01

    Osteoporosis affects many men, with significant morbidity and mortality. However, the best osteoporosis screening strategies for men are unknown. We developed an individual-level state-transition cost-effectiveness model with a lifetime time horizon to identify the cost-effectiveness of different osteoporosis screening strategies for US men involving various screening tests (dual-energy X-ray absorptiometry [DXA]; the Osteoporosis Self-Assessment Tool [OST]; or a fracture risk assessment strategy using age, femoral neck bone mineral density [BMD], and Vertebral Fracture Assessment [VFA]); screening initiation ages (50, 60, 70, or 80 years); and repeat screening intervals (5 years or 10 years). In base-case analysis, no screening was a less effective option than all other strategies evaluated; furthermore, no screening was more expensive than all strategies that involved screening with DXA or the OST risk assessment instrument, and thus no screening was "dominated" by screening with DXA or OST at all evaluated screening initiation ages and repeat screening intervals. Screening strategies that most frequently appeared as most cost-effective in base-case analyses and one-way sensitivity analyses when assuming willingness-to-pay of $50,000/quality-adjusted life-year (QALY) or $100,000/QALY included screening initiation at age 50 years with the fracture risk assessment strategy and repeat screening every 10 years; screening initiation at age 50 years with fracture risk assessment and repeat screening every 5 years; and screening initiation at age 50 years with DXA and repeat screening every 5 years. In conclusion, expansion of osteoporosis screening for US men to initiate routine screening at age 50 or 60 years would be expected to be effective and of good value for improving health outcomes. A fracture risk assessment strategy using variables of age, femoral neck BMD, and VFA is likely to be the most effective of the evaluated strategies within accepted cost

  14. Methods of inventory control.

    PubMed

    Lindley, C; Mackowiak, J

    1985-01-01

    Various methods for controlling inventory are described, and the advantages and disadvantages of each are discussed. The open-to-buy (OTB) budget method limits purchases to a specific amount of funds available for purchasing pharmaceuticals during a specified period. The emphasis of the OTB method is financial control of the pharmacy inventory. Although it is useful in monitoring and adjusting the dollar value of the inventory, it should be combined with other methods for a total inventory control system. The primary emphasis of the short-list method is to provide accurate and timely inventory information to the person responsible for order placement. The short list identifies the items that are in short supply. It is the most common feedback and control mechanism in use, but it is best suited for settings where duplicate or reserve stock is maintained and monitored by more rigorous methods. The main objective of the minimum and maximum method is to determine when and how much to order of each item. It also provides limited dollar control. The major disadvantage of this method is the time it requires to establish the minimum and maximum levels and to update them regularly to reflect changes in demand. The stock record card method is used to record information on the movement of goods in and out of the storage area. Stock cards can also be used to monitor inventory levels and facilitate order initiation. It is probably the optimum method to be used alone. The most effective system of inventory control is one employing a combination of these methods tailored to meet the institution's needs and available resources. PMID:3970028

  15. Proven Weight Loss Methods

    MedlinePlus

    Fact Sheet Proven Weight Loss Methods What can weight loss do for you? Losing weight can improve your health in a number of ways. It can lower ... at www.hormone.org/Spanish . Proven Weight Loss Methods Fact Sheet www.hormone.org

  16. DISCOURSE ON METHODS.

    ERIC Educational Resources Information Center

    BOUCHER, JOHN G.

    THE AUTHOR STATES THAT BEFORE PRESENT FOREIGN LANGUAGE TEACHING METHODS CAN BE DISCUSSED INTELLIGENTLY, THE RESEARCH IN PSYCHOLOGY AND LINGUISTICS WHICH HAS INFLUENCED THE DEVELOPMENT OF THESE METHODS MUST BE CONSIDERED. MANY FOREIGN LANGUAGE TEACHERS WERE BEGINNING TO FEEL COMFORTABLE WITH THE AUDIOLINGUAL APPROACH WHEN NOAM CHOMSKY, IN HIS 1966…

  17. Method of forming nanodielectrics