Cross Calibration of the GE Prodigy and iDXA for the Measurement of Total and Regional Body Composition in Adults (original) (raw)
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PloS one, 2017
Dual energy x-ray absorptiometry (DXA) is an established technique for the measurement of body composition. Reference values for these variables, particularly those related to fat mass, are necessary for interpretation and accurate classification of those at risk for obesity-related health complications and in need of lifestyle modifications (diet, physical activity, etc.). Currently, there are no reference values available for GE-Healthcare DXA systems and it is known that whole-body and regional fat mass measures differ by DXA manufacturer. To develop reference values by age and sex for DXA-derived fat mass measurements with GE-Healthcare systems. A de-identified sample of 3,327 participants (2,076 women, 1,251 men) was obtained from Ball State University's Clinical Exercise Physiology Laboratory and University of Wisconsin-Milwaukee's Physical Activity & Health Research Laboratory. All scans were completed using a GE Lunar Prodigy or iDXA and data reported included percen...
2017
Background Dual energy x-ray absorptiometry (DXA) is an established technique for the measurement of body composition. Reference values for these variables, particularly those related to fat mass, are necessary for interpretation and accurate classification of those at risk for obesityrelated health complications and in need of lifestyle modifications (diet, physical activity, etc.). Currently, there are no reference values available for GE-Healthcare DXA systems and it is known that whole-body and regional fat mass measures differ by DXA manufacturer. Objective To develop reference values by age and sex for DXA-derived fat mass measurements with GE-Healthcare systems. Methods A de-identified sample of 3,327 participants (2,076 women, 1,251 men) was obtained from Ball State University\u27s Clinical Exercise Physiology Laboratory and University of Wisconsin- Milwaukee\u27s Physical Activity & Health Research Laboratory. All scans were completed using a GE Lunar Prodigy or iDXA and da...
iDXA, Prodigy, and DPXL Dual-Energy X-ray Absorptiometry Whole-Body Scans: A Cross-Calibration Study
Journal of Clinical Densitometry, 2009
Purpose: Total body fat, lean, and bone mineral content (BMC) in addition to regional fat and lean mass values for arms, legs, and trunk were compared across a pencil-beam (Lunar DPXL) and 2 fan-beam (GE Lunar Prodigy and GE Lunar iDXA) dual-energy X-ray absorptiometry (DXA) systems. Methods: Subjects were a multiethnic sample of 99 healthy adult males (47%) and females (mean AE SD: age, 46.3 AE 16.9 yr; weight, 73.4 AE 16.6 kg; height, 167.6 AE 9.7 cm; body mass index, 26.0 AE 5.2 kg/m 2 ) who had whole-body scans performed within a 3-h period on the 3 systems. Repeated measures ANOVA was used to test the null hypothesis that the mean values for the 3 systems were equal. Translation equations between the methods were derived using regression techniques. Results: Bone mineral content (BMC): For both genders, total BMC by iDXA was lower ( p 0.004) than the other systems. Lean: for males, iDXA was lower ( p 0.03) than the other systems for total, trunk, and arms. For females, DPXL estimated higher ( p ! 0.001) lean mass compared with the other systems for total, trunk, and arms, but iDXA estimated greater legs lean mass. For both genders, all DPXL mean values were greater than Prodigy mean values ( p ! 0.001).
2007
Objective. Dual-energy X-ray absorptiometry (DXA) is a tool to measure body composition. However, its application is limited in individuals who do not fit in the scanning area. Therefore, the aim of this study was to (i) validate a new method to measure body composition in obese individuals using DXA; and (ii) compare to an existing method. Methods. Body composition was measured using DXA in 50 individuals between 17-68 years with varying body fatness (BMI: 19.9-39.3 kg/m 2 ) and body weight (56.2-120.9 kg). Body composition (fat mass, fatfree soft tissue and bone mineral content) was compared using the arm-replaced (AR) vs existing half-body (HB) method, compared to the reference whole-body scan (RS). Linear regression and Bland-Altman analyses assessed the accuracy and intra-tester reliability.
2000
Background: Dual-energy X-ray absorptiometry (DXA) has be- comeoneofthemostfrequentlyusedmethodsforestimatinghuman body composition. Although the DXA technique has been validated for the measurement of fat-free mass and fat mass, differences in calibration between instruments produced by different manufactur- ers, as well as between different models produced by the same manufacturer, have been reported. Objective: The objective was to compare the calibration of the
Measuring body composition in overweight individuals by dual energy x-ray absorptiometry
BMC medical imaging, 2005
BACKGROUND: Dual energy x-ray absorptiometry (DXA) is widely used for body composition measurements in normal-weight and overweight/obese individuals. The limitations of bone densitometers have been frequently addressed. However, the possible errors in assessing body composition in overweight individuals due to incorrect positioning or limitations of DXA to accurately assess both bone mineral density and body composition in obese individuals have not received much attention and are the focus of this report. DISCUSSION: We discuss proper ways of measuring overweight individuals and point to some studies where that might not have been the case. It appears that currently, the most prudent approach to assess body composition of large individuals who cannot fit under the scanning area would be to estimate regional fat, namely the regions of thigh and/or abdomen. Additionally, using two-half body scans, although time consuming, may provide a relatively accurate measurement of total body f...
European Journal of Clinical Nutrition, 2016
Background-Comparison of percent fat mass across different body composition analysis devices is important given variation in technology accuracy and precision, as well as the growing need for cross-validation of devices often applied across longitudinal studies. Subjects/Methods-We compared EchoMRI-AH and Lunar iDXA quantification of percent body fat (PBF) in 84 adults (43M, 41F) with mean age 39.7±15.9 y and BMI 26.2±5.3 kg/m 2. Results-PBF correlated strongly between devices (r>0.95, p<0.0001). A prediction equation was derived in half of the subjects, and the other half were used to cross-validate the proposed equation (EchoMRI-AH PBF=[0.94*iDXA PBF]+[0.14*Age]+[3.3*Female]−8.83). Mean PBF difference (predicted-measured) in the validation group was not different from 0 (diff=0.27%, 95%CI: −0.42-0.96, p=0.430). Bland-Altman plots showed a bias with higher measured PBF on EchoMRI-AH versus iDXA in all 84 subjects (β=0.13, p<0.0001). Conclusions-The proposed prediction equation was valid in our cross-validation sample, and has the potential to be applied across multicenter studies.
American Journal of Clinical Nutrition
Dual-energy X-ray absorptiometry (DXA) is widely used to assess body composition in research and clinical practice. Several studies have evaluated its accuracy in healthy persons; however, little attention has been directed to the same issue in patients. The objective was to compare the accuracy of the Lunar Prodigy DXA for body-composition analysis with that of the reference 4-component (4C) model in healthy subjects and in patients with 1 of 3 disease states. A total of 215 subjects aged 5.0-21.3 y (n = 122 healthy nonobese subjects, n = 55 obese patients, n = 26 cystic fibrosis patients, and n = 12 patients with glycogen storage disease). Fat mass (FM), fat-free mass (FFM), and weight were measured by DXA and the 4C model. The accuracy of DXA-measured body-composition outcomes differed significantly between groups. Factors independently predicting bias in weight, FM, FFM, and percentage body fat in multivariate models included age, sex, size, and disease state. Biases in FFM were...
In vivo validation of whole body composition estimates from dual-energy X-ray absorptiometry
Journal of applied physiology (Bethesda, Md. : 1985), 1997
We validated whole body composition estimates from dual-energy X-ray absorptiometry (DEXA) against estimates from a four-component model to determine whether accuracy is affected by gender, race, athletic status, or musculoskeletal development in young adults. Measurements of body density by hydrostatic weighing, body water by deuterium dilution, and bone mineral by whole body DEXA were obtained in 172 young men (n = 91) and women (n = 81). Estimates of body fat (%Fat) from DEXA (%FatDEXA) were highly correlated with estimates of body fat from the four-component model [body density, total body water, and total body mineral (%Fatd,w,m); r = 0.94, standard error of the estimante (SEE) = 2.8% body mass (BM)] with no significant difference between methods [mean of the difference +/- SD of the difference = -0.4 +/- 2.9 (SD) % BM, P = 0.10] in women and men. On the basis of the comparison with %Fatd,w,m, estimates of %FatDEXA were slightly more accurate than those from body density (r = 0...