Comparison of in vivo body composition using two lunar dual-energy X-ray absorptiometers

Oldroyd, B.; Milner, Richard; Stewart, S. P.; Smith, A.H.; Westmacott, CF; Smith, Mark A.

doi:10.1016/s0969-8043(97)00068-7

Cited by 7 publications

(8 citation statements)

References 1 publication

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“…It has been asserted that DXA allows precise measurements of bone mineral content [21], but the source of variation in the results caused by different quality assurance data in the hardware of the same models of DXA scanners has not been sufficiently clarified [35]. When TBMC and TBMD were measured in 8 adolescents by the two Lunar DPX-L instruments used in the present study significant differences were found [30].…”

Section: Discussionmentioning

confidence: 56%

Whole-Body Bone Mineral Measurements in 15-Year-Old Swedish Adolescents

Lötborn¹,

Bratteby²,

Samuelson³

et al. 1999

Osteoporosis International

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Bone mineral area (BA), total bone mineral content (TBMC) and total bone mineral density (TBMD) were assessed by dual-energy X-ray absorptiometry (DXA) in 396 randomly selected, healthy 15-year-old Swedish boys and girls. The influence of body size, pubertal development, physical activity level (PAL), total energy expenditure (TEE), dietary intake of energy, calcium and vitamin D, and alcohol and smoking habits on TBMC and TBMD were examined in bi- and multivariate analyses. In bivariate analyses BA, TBMC and TBMD showed strong correlations with weight, height and TEE in both sexes. In boys but not in girls these bone variables were significantly correlated with dietary intakes of energy, calcium and vitamin D. No significant correlations were found between PAL and the three bone variables. In multivariate analyses with TBMC as dependent variable BA, height, weight and Tanner stages explained 88% and 87% of the variance in boys and girls respectively. In similar analyses with TBMD as dependent variable the corresponding figures were 50% and 54%. The major part of the variance in all these models was explained by BA, and only a few percent by all the other independent variables. No significant reduction was found when TEE or daily intakes of calcium or vitamin D were introduced into the models. These results illustrate the importance of including BA, weight and height as independent variables in regression models of TBMC to avoid spurious associations with other variables in the analyses. The results may also indicate that in normal Swedish adolescents environmental factors such as dietary intake of nutrients play a minor role as determinants of bone mineralization. High levels of physical activity and bone mineral measures possibly explain the lack of significant correlations between these variables and do not imply a lack of association.

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Section: Discussionmentioning

confidence: 56%

Whole-Body Bone Mineral Measurements in 15-Year-Old Swedish Adolescents

Lötborn¹,

Bratteby²,

Samuelson³

et al. 1999

Osteoporosis International

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“…GE Lunar vs. Hologic)(4, 14–17), within manufacturer models using different technologies (pencil-beam versus fan-beam)(3, 4, 6, 13, 18), within the same manufacturer using the same technologies(19))(4, 20) and within the same manufacturer and same instrument but different software versions(15, 19). This study reports on differences between the newest version from GE Lunar, the iDXA (fan-beam) compared to older versions namely the DPXL (pencil-beam) and Prodigy (fan-beam).…”

Section: Discussionmentioning

confidence: 99%

iDXA, Prodigy, and DPXL Dual-Energy X-ray Absorptiometry Whole-Body Scans: A Cross-Calibration Study

Hull

Thornton

et al. 2009

Journal of Clinical Densitometry

104

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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 DPX-L) and two fan-beam (GE Lunar Prodigy and GE Lunar iDXA) dual energy x-ray absorptiometry (DXA) systems.Methods-Subjects were a multi-ethnic sample of 99 healthy adult males (47%) and females (mean ± SD: age 46.3 ± 16.9 yrs; weight 73.4±16.6 kg; height 167.6±9.7 cm; BMI 26.0±5.2 kg/m 2 ) who had whole-body scans performed within a 3 hour period on the three systems. Repeated measures ANOVA was used to test the null hypothesis that the mean values for the three systems were equal. Translation equations between the methods were derived using regression techniques. Results-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 to 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).Fat: In females, all 3 systems were different from each other for total, trunk, and legs (P≤0.04). For arms, DPXL and iDXA were higher than Prodigy (P<0.0004). For males, DPXL was less (P<0.001) for total body, trunk and legs compared to the other two systems and greater than Prodigy only for arms (P<0.0007). These data were used to derive translation equations between systems. For several measurements, the differences between systems were related to gender.Conclusion-For estimation of BMC and body composition, there was high agreement between all DXA systems (R 2 =0.85 to 0.99). Even so, cross-calibration equations should be used to examine data across systems to avoid erroneous conclusions.

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“…This study is the first to report cross calibration of regional body composition between two modern fan‐beam scanners. Existing cross‐calibration reports of regional body composition have compared older pencil‐beam scanners (6,19,21) or a first generation fan‐beam scanner to a pencil‐beam scanner (5). Cross‐calibration reports on pencil‐beam scanners found significant differences in regional fat and nonosseous lean mass for different models of the same maker (19,21) and between scanners produced by different makers (6).…”

Section: Discussionmentioning

confidence: 99%

“…Precision within a given device is high (1,2,3), but between different devices there can be significant differences in body composition. These differences are generally greatest between devices from different manufacturers (4,5,6), but also occur for different models from the same manufacturer (1,7,8) and even for different devices of the same make and model (9). Most reports of DXA cross‐calibration for body composition have focused on whole body data (1,3,10), with only a few examining comparability of regional body composition between scanners (5,6).…”

Section: Introductionmentioning

confidence: 99%

Regional Body Composition: Cross‐calibration of DXA Scanners—QDR4500W and Discovery Wi

Covey

Berry

Hacker

2010

Obesity

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articlesMethods and techniques comprised of three compartments: BMC, nonosseous lean mass, and fat mass. This research was approved by the institutional review board at University of Illinois at Chicago. Subjects gave written informed consent at the initial study visit. subjects Forty-one women over 18 years of age enrolled in the study. To be eligible, subjects were able to lie supine for ~6 min, had body weight <137 kg (table weight limit is 136 kg for the QDR4500W, 159 kg for the Discovery Wi), and were not pregnant. Subjects were recruited primarily through posted flyers and mass e-mails directed toward faculty, staff, and students in the College of Nursing at the University of Illinois at Chicago, but a few subjects were recruited through word of mouth. Body weight was determined using a balance-beam scale and recorded to the nearest 0.2 kg. Height was determined with a stadiometer to the nearest 0.6 cm. BMI was calculated as body mass in kilograms (kg)/ height in meters squared (m 2 ). Body compositionBody composition was measured by DXA whole body scans performed on two different scanners: QDR4500W and Discovery Wi (Hologic, Bedford, MA). Both DXA scanners use fan-beam technology and switch between two X-ray potentials (100 and 140 kVp) from an X-ray source mounted beneath the subject. The following software versions were used: version 9.10 for the QDR4500W and QDR for Windows XP, version 12.6 for the Discovery Wi. The manufacturer reported that the soft tissue analysis for nonosseous lean mass would be lower and fat mass higher with software version 12.6 compared to versions 9-11. Quality control was maintained by daily scanning of a spine phantom constructed of hydroxyapatite molded from a cadaver spine (L 1 -L 4 ) encased in epoxy resin. The coefficient of variation for spine phantom bone mineral density was 0.48% for the QDR4500W and 0.49% for the Discovery Wi. One highly experienced researcher performed and analyzed all scans and great care was taken in consistent positioning. Subjects were placed in the supine position on the scanner bed with the body centered along the longitudinal axis. Shoulders were gently pressed down to provide separation between the base of the skull and the top of the shoulder. Forearms were positioned parallel to the longitudinal edge of the scanner bed just within the limit of the scanning area. Legs were fully extended with the toes pointing slightly medially and feet were secured with a light weight cotton twill tape to avoid foot motion during the scan.

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Comparison of in vivo body composition using two lunar dual-energy X-ray absorptiometers

Cited by 7 publications

References 1 publication

Whole-Body Bone Mineral Measurements in 15-Year-Old Swedish Adolescents

Whole-Body Bone Mineral Measurements in 15-Year-Old Swedish Adolescents

iDXA, Prodigy, and DPXL Dual-Energy X-ray Absorptiometry Whole-Body Scans: A Cross-Calibration Study

Regional Body Composition: Cross‐calibration of DXA Scanners—QDR4500W and Discovery Wi

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