The Experts below are selected from a list of 47016 Experts worldwide ranked by ideXlab platform
Eric Ravussin - One of the best experts on this subject based on the ideXlab platform.
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assessment of echomri ah versus dual energy X Ray Absorptiometry by idXa to measure human body composition
European Journal of Clinical Nutrition, 2017Co-Authors: Kara L Marlatt, Frank L Greenway, Eric RavussinAbstract:Assessment of EchoMRI-AH versus dual-energy X-Ray Absorptiometry by iDXA to measure human body composition
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assessment of echomri ah versus dual energy X Ray Absorptiometry to measure human body composition
International Journal of Obesity, 2011Co-Authors: Jose E Galgani, Steven R Smith, Eric RavussinAbstract:Assessment of EchoMRI-AH versus dual-energy X-Ray Absorptiometry to measure human body composition
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use of dual energy X Ray Absorptiometry in obese individuals
The American Journal of Clinical Nutrition, 1995Co-Authors: P A Tataranni, Eric RavussinAbstract:Dual-energy X-Ray Absorptiometry (DXA) provides precise measurements of body composition in humans. Because its use in obese subjects is limited by the size of the scanning area, we eXplored the possibility of estimating whole-body composition from DXA half-body scans. Body composition of 183 subjects with a wide range of body sizes [body mass indeX (BMI ; in kg/m 2 ) of 17.7-52.8] was assessed by DXA and hydrodensitometry. Subjects fitting in the DXA scanning area (group A, n = 156) were scanned once whereas subjects eXceeding it (group B, n = 27) were scanned twice, once for each side of the body. When body-composition results for the right and left sides were compared, only minimal differences between the two sides of the body were found in both groups. Least-squares-regression analysis of whole-body composition by hydrodensitometry on DXA gave the following results : percent body fat, r 2 = 0.89 (SEE = 4.1%) ; fat-free mass, r 2 = 0.89 (SEE = 3.72 kg) ; and fat mass, r 2 = 0.95 (SEE = 3.57 kg). Similar r 2 values and SEEs were obtained for percent body fat when only results from DXA half-body scans of all subjects were considered : right side, r 2 = 0.90 (SEE = 4.1%) ; and left side, r 2 = 0.89 (SEE = 4.2%). The error in predicting body composition by hydrodensitometry from DXA whole- or half-body scans was not affected by the subject's body size and/or scanning technique. In conclusion, our results indicate that half-body scan values by DXA accurately predict whole-body composition.
Glen M Blake - One of the best experts on this subject based on the ideXlab platform.
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obesity increases precision errors in total body dual energy X Ray Absorptiometry measurements
Journal of Clinical Densitometry, 2015Co-Authors: K M Knapp, Ignac Fogelman, Joanne R Welsman, S J Hopkins, Andrew Shallcross, Glen M BlakeAbstract:Total body (TB) dual-energy X-Ray Absorptiometry (DXA) is increasingly being used to measure body composition in research and clinical settings. This study investigated the effect of body mass indeX (BMI) and body fat on precision errors for total and regional TB DXA measurements of bone mineral density, fat tissue, and lean tissue using the GE Lunar Prodigy (GE Healthcare, Bedford, UK). One hundred forty-four women with BMI's ranging from 18.5 to 45.9 kg/m(2) were recruited. Participants had duplicate DXA scans of the TB with repositioning between eXaminations. Participants were divided into 3 groups based on their BMI, and the root mean square standard deviation and the percentage coefficient of variation were calculated for each group. The root mean square standard deviation (percentage coefficient of variation) for the normal ( 30 kg/m²; n = 32) BMI groups, respectively, were total BMD (g/cm(2)): 0.009 (0.77%), 0.009 (0.69%), 0.011 (0.91%); total fat (g): 545 (2.98%), 486 (1.72%), 677 (1.55%); total lean (g): 551 (1.42%), 540 (1.34%), and 781 (1.68%). These results suggest that serial measurements in obese subjects should be treated with caution because the least significant change may be larger than anticipated.
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an update on dual energy X Ray Absorptiometry
Seminars in Nuclear Medicine, 2010Co-Authors: Glen M Blake, Ignac FogelmanAbstract:Dual-energy X-Ray Absorptiometry (DXA) scans to measure bone mineral density at the spine and hip have an important role in the evaluation of individuals at risk of osteoporosis, and in helping clinicians advise patients about the appropriate use of antifracture treatment. Compared with alternative bone densitometry techniques, hip and spine DXA eXaminations have several advantages that include a consensus that bone mineral density results should be interpreted using the World Health Organization T score definition of osteoporosis, a proven ability to predict fracture risk, proven effectiveness at targeting antifracture therapies, and the ability to monitor response to treatment. This review discusses the evidence for these and other clinical aspects of DXA scanning. Particular attention is directed at the new World Health Organization Fracture Risk Assessment Tool (FRAX) algorithm, which uses clinical risk factors in addition to a hip DXA scan to predict a patient's 10-year probability of suffering an osteoporotic fracture. We also discuss the recently published clinical guidelines that incorporate the FRAX fracture risk assessment in decisions about patient treatment.
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the clinical role of dual energy X Ray Absorptiometry
European Journal of Radiology, 2009Co-Authors: Glen M Blake, Ignac FogelmanAbstract:Dual energy X-Ray Absorptiometry (DXA) measurements of hip and spine bone mineral density (BMD) have an important role in the evaluation of individuals at risk of osteoporosis, and in helping clinicians advise patients about the appropriate use of anti-fracture treatment. Compared with alternative bone densitometry techniques, hip and spine DXA eXaminations have a number of advantages that include a consensus that BMD results can be interpreted using the World Health Organisation (WHO) T-score definition of osteoporosis, a proven ability to predict fracture risk, proven effectiveness at targeting anti-fracture therapies, and the ability to monitor response to treatment. This review discusses the evidence for these and other clinical aspects of DXA scanning, including its role in the new WHO algorithm for treating patients on the basis of their individual fracture risk.
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role of dual energy X Ray Absorptiometry in the diagnosis and treatment of osteoporosis
Journal of Clinical Densitometry, 2007Co-Authors: Glen M Blake, Ignac FogelmanAbstract:Dual energy X-Ray Absorptiometry (DXA) measurements of spine and hip bone mineral density (BMD) (referred to here as central DXA) have an important role as a clinical tool for the evaluation of individuals at risk of osteoporosis, and in helping clinicians give advice to patients about the appropriate use of antifracture treatment. Compared with alternative bone densitometry techniques such quantitative computed tomography (QCT), peripheral DXA (pDXA) and quantitative ultrasound (QUS), central DXA has a number of significant advantages that include a consensus that BMD results can be interpreted using the World Health Organization (WHO) T-score definition of osteoporosis, a proven ability to predict fracture risk, and proven effectiveness at targeting antifracture treatments. This review article discusses the evidence for these and other advantages of central DXA, including its role in the new WHO algorithm for treating patients on the basis of individual fracture risk.
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visual assessment of vertebral deformity by X Ray Absorptiometry a highly predictive method to eXclude vertebral deformity
Osteoporosis International, 2000Co-Authors: Jianmei Li, Glen M Blake, P Steiger, Harry K Genant, Ignac FogelmanAbstract:The accurate identification of prevalent vertebral fractures is important in both the clinical and research setting as they are associated with increased risk of further fracture and irreversible clinical consequences. This study reports a direct comparison of prevalent vertebral deformity identification using X-Ray Absorptiometry (XA) scans, acquired on a dual-energy X-Ray Absorptiometry (DXA) machine, and conventional radiographs in a diverse group of 161 postmenopausal women, ranging from healthy subjects with normal bone mineral density (BMD) to osteoporotic subjects with multiple vertebral deformities. Deformities were identified by a trained operator by visual assessment of the XA scans (VXA) and semiquantitatively by an eXperienced radiologist on the conventional radiographs (XSQ). Subjects were recruited prospectively and were triaged according to their VXA results into normal, equivocal and definite deformity groups. VXA and XSQ demonstrated good agreement (96.3%, κ= 0.79) in classifying vertebrae as normal or deformed in the 1978 of 2093 vertebrae deemed analyzable on both the XA scans and conventional radiographs. VXA showed good sensitivity (91.9%) in the identification of moderate/severe XSQ deformities and an eXcellent negative predictive value (98.0%) was produced when VXA was used to distinguish subjects without vertebral deformities from those with possible or definite deformities on a per subject basis. The majority of disagreement between the two methods resulted from different classification of mild wedge and endplate deformities and the poor visualization of upper thoracic vertebrae on the XA scans. Agreement improved, particularly on a per subject basis, when analysis was restricted to the vertebral levels from L4 to T7. Visual triage of XA scans by a trained operator would seem to be swift, convenient and cost-effective method, with eXcellent negative predictive value, to distinguish subjects with very low risk of vertebral deformities from those with possible deformities. These ‘normal’ subjects can then be eXcluded prior to performing conventional radiographs and further time-consuming and costly methods of vertebral deformity assessment such as XSQ by an eXperienced radiologist and/or quantitative morphometry. VXA may prove useful in the clinical evaluation of patients at risk of osteoporosis as an adjunct to BMD scans or in the selection of subjects for osteoporosis-related clinical trials.
Ignac Fogelman - One of the best experts on this subject based on the ideXlab platform.
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obesity increases precision errors in total body dual energy X Ray Absorptiometry measurements
Journal of Clinical Densitometry, 2015Co-Authors: K M Knapp, Ignac Fogelman, Joanne R Welsman, S J Hopkins, Andrew Shallcross, Glen M BlakeAbstract:Total body (TB) dual-energy X-Ray Absorptiometry (DXA) is increasingly being used to measure body composition in research and clinical settings. This study investigated the effect of body mass indeX (BMI) and body fat on precision errors for total and regional TB DXA measurements of bone mineral density, fat tissue, and lean tissue using the GE Lunar Prodigy (GE Healthcare, Bedford, UK). One hundred forty-four women with BMI's ranging from 18.5 to 45.9 kg/m(2) were recruited. Participants had duplicate DXA scans of the TB with repositioning between eXaminations. Participants were divided into 3 groups based on their BMI, and the root mean square standard deviation and the percentage coefficient of variation were calculated for each group. The root mean square standard deviation (percentage coefficient of variation) for the normal ( 30 kg/m²; n = 32) BMI groups, respectively, were total BMD (g/cm(2)): 0.009 (0.77%), 0.009 (0.69%), 0.011 (0.91%); total fat (g): 545 (2.98%), 486 (1.72%), 677 (1.55%); total lean (g): 551 (1.42%), 540 (1.34%), and 781 (1.68%). These results suggest that serial measurements in obese subjects should be treated with caution because the least significant change may be larger than anticipated.
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an update on dual energy X Ray Absorptiometry
Seminars in Nuclear Medicine, 2010Co-Authors: Glen M Blake, Ignac FogelmanAbstract:Dual-energy X-Ray Absorptiometry (DXA) scans to measure bone mineral density at the spine and hip have an important role in the evaluation of individuals at risk of osteoporosis, and in helping clinicians advise patients about the appropriate use of antifracture treatment. Compared with alternative bone densitometry techniques, hip and spine DXA eXaminations have several advantages that include a consensus that bone mineral density results should be interpreted using the World Health Organization T score definition of osteoporosis, a proven ability to predict fracture risk, proven effectiveness at targeting antifracture therapies, and the ability to monitor response to treatment. This review discusses the evidence for these and other clinical aspects of DXA scanning. Particular attention is directed at the new World Health Organization Fracture Risk Assessment Tool (FRAX) algorithm, which uses clinical risk factors in addition to a hip DXA scan to predict a patient's 10-year probability of suffering an osteoporotic fracture. We also discuss the recently published clinical guidelines that incorporate the FRAX fracture risk assessment in decisions about patient treatment.
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the clinical role of dual energy X Ray Absorptiometry
European Journal of Radiology, 2009Co-Authors: Glen M Blake, Ignac FogelmanAbstract:Dual energy X-Ray Absorptiometry (DXA) measurements of hip and spine bone mineral density (BMD) have an important role in the evaluation of individuals at risk of osteoporosis, and in helping clinicians advise patients about the appropriate use of anti-fracture treatment. Compared with alternative bone densitometry techniques, hip and spine DXA eXaminations have a number of advantages that include a consensus that BMD results can be interpreted using the World Health Organisation (WHO) T-score definition of osteoporosis, a proven ability to predict fracture risk, proven effectiveness at targeting anti-fracture therapies, and the ability to monitor response to treatment. This review discusses the evidence for these and other clinical aspects of DXA scanning, including its role in the new WHO algorithm for treating patients on the basis of their individual fracture risk.
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role of dual energy X Ray Absorptiometry in the diagnosis and treatment of osteoporosis
Journal of Clinical Densitometry, 2007Co-Authors: Glen M Blake, Ignac FogelmanAbstract:Dual energy X-Ray Absorptiometry (DXA) measurements of spine and hip bone mineral density (BMD) (referred to here as central DXA) have an important role as a clinical tool for the evaluation of individuals at risk of osteoporosis, and in helping clinicians give advice to patients about the appropriate use of antifracture treatment. Compared with alternative bone densitometry techniques such quantitative computed tomography (QCT), peripheral DXA (pDXA) and quantitative ultrasound (QUS), central DXA has a number of significant advantages that include a consensus that BMD results can be interpreted using the World Health Organization (WHO) T-score definition of osteoporosis, a proven ability to predict fracture risk, and proven effectiveness at targeting antifracture treatments. This review article discusses the evidence for these and other advantages of central DXA, including its role in the new WHO algorithm for treating patients on the basis of individual fracture risk.
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visual assessment of vertebral deformity by X Ray Absorptiometry a highly predictive method to eXclude vertebral deformity
Osteoporosis International, 2000Co-Authors: Jianmei Li, Glen M Blake, P Steiger, Harry K Genant, Ignac FogelmanAbstract:The accurate identification of prevalent vertebral fractures is important in both the clinical and research setting as they are associated with increased risk of further fracture and irreversible clinical consequences. This study reports a direct comparison of prevalent vertebral deformity identification using X-Ray Absorptiometry (XA) scans, acquired on a dual-energy X-Ray Absorptiometry (DXA) machine, and conventional radiographs in a diverse group of 161 postmenopausal women, ranging from healthy subjects with normal bone mineral density (BMD) to osteoporotic subjects with multiple vertebral deformities. Deformities were identified by a trained operator by visual assessment of the XA scans (VXA) and semiquantitatively by an eXperienced radiologist on the conventional radiographs (XSQ). Subjects were recruited prospectively and were triaged according to their VXA results into normal, equivocal and definite deformity groups. VXA and XSQ demonstrated good agreement (96.3%, κ= 0.79) in classifying vertebrae as normal or deformed in the 1978 of 2093 vertebrae deemed analyzable on both the XA scans and conventional radiographs. VXA showed good sensitivity (91.9%) in the identification of moderate/severe XSQ deformities and an eXcellent negative predictive value (98.0%) was produced when VXA was used to distinguish subjects without vertebral deformities from those with possible or definite deformities on a per subject basis. The majority of disagreement between the two methods resulted from different classification of mild wedge and endplate deformities and the poor visualization of upper thoracic vertebrae on the XA scans. Agreement improved, particularly on a per subject basis, when analysis was restricted to the vertebral levels from L4 to T7. Visual triage of XA scans by a trained operator would seem to be swift, convenient and cost-effective method, with eXcellent negative predictive value, to distinguish subjects with very low risk of vertebral deformities from those with possible deformities. These ‘normal’ subjects can then be eXcluded prior to performing conventional radiographs and further time-consuming and costly methods of vertebral deformity assessment such as XSQ by an eXperienced radiologist and/or quantitative morphometry. VXA may prove useful in the clinical evaluation of patients at risk of osteoporosis as an adjunct to BMD scans or in the selection of subjects for osteoporosis-related clinical trials.
Andrew Davenport - One of the best experts on this subject based on the ideXlab platform.
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comparison of resting and total energy eXpenditure in peritoneal dialysis patients and body composition measured by dual energy X Ray Absorptiometry
European Journal of Clinical Nutrition, 2016Co-Authors: Sally Elkateb, Sivakumar Sridharan, Ken Farrington, Andrew DavenportAbstract:Comparison of resting and total energy eXpenditure in peritoneal dialysis patients and body composition measured by dual-energy X-Ray Absorptiometry
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assessment of body composition in peritoneal dialysis patients using bioelectrical impedance and dual energy X Ray Absorptiometry
American Journal of Nephrology, 2011Co-Authors: Antje Furstenberg, Andrew DavenportAbstract:Introduction: Protein energy wasting is closely related to increased morbidity and mortality in peritoneal dialysis (PD) patients. Simple reliable and easily available methods of determining nutritional status and recognition of short-term changes in body composition are therefore important for clinical practice. Methods: We compared whole-body and segmental composition using multifrequency bioelectrical impedance analysis (MF-BIA) and dual-energy X-Ray Absorptiometry (DEXA) in 104 stable PD patients. Results: Assessment of whole-body composition showed that lean body mass (LBM) was highly correlated with good method agreement using DEXA as the reference test (r = 0.95, p Conclusion: MF-BIA may potentially be a useful tool for determining nutritional status in PD patients and serial estimations may help recognize short-term changes in body composition.
Steven B. Heymsfield - One of the best experts on this subject based on the ideXlab platform.
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dual energy X Ray Absorptiometry body composition reference values from nhanes
PLOS ONE, 2009Co-Authors: Thomas L Kelly, Kevin E Wilson, Steven B. HeymsfieldAbstract:In 2008 the National Center for Health Statistics released a dual energy X-Ray Absorptiometry (DXA) whole body dataset from the NHANES population-based sample acquired with modern fan beam scanners in 15 counties across the United States from 1999 through 2004. The NHANES dataset was partitioned by gender and ethnicity and DXA whole body measures of %fat, fat mass/height2, lean mass/height2, appendicular lean mass/height2, %fat trunk/%fat legs ratio, trunk/limb fat mass ratio of fat, bone mineral content (BMC) and bone mineral density (BMD) were analyzed to provide reference values for subjects 8 to 85 years old. DXA reference values for adults were normalized to age; reference values for children included total and sub-total whole body results and were normalized to age, height, or lean mass. We developed an obesity classification scheme by using estabbody mass indeX (BMI) classification thresholds and prevalences in young adults to generate matching classification thresholds for Fat Mass IndeX (FMI; fat mass/height2). These reference values should be helpful in the evaluation of a variety of adult and childhood abnormalities involving fat, lean, and bone, for establishing entry criteria into clinical trials, and for other medical, research, and epidemiological uses.
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dual energy X Ray Absorptiometry lean soft tissue hydration independent contributions of intra and eXtracellular water
American Journal of Physiology-endocrinology and Metabolism, 2004Co-Authors: Mariepierre Stonge, Zimian Wang, Mary Horlick, Jack Wang, Steven B. HeymsfieldAbstract:Dual-energy X-Ray Absorptiometry (DEXA) provides a measure of lean soft tissue (LST). LST hydration, often assumed to be constant, is relevant to several aspects of DEXA body composition estimates....
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intermuscular adipose tissue free skeletal muscle mass estimation by dual energy X Ray Absorptiometry in adults
Journal of Applied Physiology, 2004Co-Authors: Jaehee Kim, Dympna Gallagher, Stanley Heshka, Donald P Kotler, Laurel E S Mayer, Jeanine Albu, Wei Shen, Pamela U Freda, Steven B. HeymsfieldAbstract:Skeletal muscle (SM) is a large and physiologically important compartment. Adipose tissue is found interspersed between and within SM groups and is referred to as intermuscular adipose tissue (IMAT). The study objective was to develop prediction models linking appendicular lean soft tissue (ALST) estimates by dual-energy X-Ray Absorptiometry (DXA) with whole body IMAT-free SM quantified by magnetic resonance imaging. ALST and total-body IMAT-free SM were evaluated in 270 healthy adults [body mass indeX (BMI) of 16 kg/m(2)) but not in those with a BMI of <16 kg/m(2) (n = 12). The DXA-based models are accurate for predicting IMAT-free SM in selected populations and thus provide a new opportunity for quantifying SM in physiological and epidemiological investigations.
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are dual energy X Ray Absorptiometry regional estimates associated with visceral adipose tissue mass
International Journal of Obesity, 2002Co-Authors: Yongwoo Park, Steven B. Heymsfield, Dympna GallagherAbstract:Are dual-energy X-Ray Absorptiometry regional estimates associated with visceral adipose tissue mass?
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dual energy X Ray Absorptiometry body composition model review of physical concepts
American Journal of Physiology-endocrinology and Metabolism, 1996Co-Authors: Angelo Pietrobelli, Caterina Formica, Zimian Wang, Steven B. HeymsfieldAbstract:Although dual-energy X-Ray Absorptiometry (DXA) is widely used in clinical research as a means of quantifying body composition, there remains at present little published information that reviews the method's underlying physical basis. Because a clear understanding of DXA physical concepts is integral to appropriate use and interpretation, we present here a three-section review that includes both relevant in vitro and in vivo eXperimental demonstrations. In the first section we describe the main physical principles on which DXA is based. The section that follows presents a step-by-step analysis of the DXA two-component soft tissue model. In the final section we demonstrate how knowledge of physical concepts can lead to resolution of important methodological concerns, such as the influence of hydration changes on DXA fat estimates. A thorough understanding of DXA physical concepts provides a basis for appropriate interpretation of measurement results and stimulates many new and important research questions.