Bone and Body Composition Measurements of Small Subjects: Discrepancies from Software for Fan-Beam Dual Energy X-Ray Absorptiometry

Koo, Winston; Hammami, Mouhanad; Shypailo, Roman J.; Ellis, Kenneth J.

doi:10.1080/07315724.2004.10719406

Cited by 30 publications

(16 citation statements)

References 14 publications

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“…DXA has been validated and used in all age ranges to estimate body fat and fat-free mass (FFM). [11][12][13] However, the requirement for remaining motionless and the exposure to radiation limit its use in pediatric population and prohibits the possibility of obtaining repeated measures. Having accurate, precise and rapid measures of body composition using technology that allows children to move would greatly facilitate longitudinal studies during early childhood.…”

Section: Introductionmentioning

confidence: 99%

QMR: validation of an infant and children body composition instrument using piglets against chemical analysis

2010

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Objective: This study was undertaken to validate the first quantitative nuclear magnetic resonance (QMR) instrument designed and built to assess body composition in children from birth to adulthood (up to 50 kg). Design: A total of 50 pigs weighing between 3.0 and 49.1 kg were studied. Each piglet's body composition was assessed by quantitative nuclear magnetic resonance (QMR, EchoMRI-AH small), whole-body chemical carcass analysis for lipid and water content, and dual-energy X-ray absorptiometry (DXA, Hologic QDR 4500, using infant or adult whole-body scan acquisition programs where appropriate). Twenty-five piglets (3.1-47.2 kg) were randomly selected to calibrate the QMR instrument. The remaining 25 piglets (3.0-49.1 kg) were used to validate the instrument. Results: The precision of QMR to estimate fat mass (FM), fat-free mass (FFM) and total body water (TBW) for five consecutive scans was excellent (1.3, 0.9 and 0.9%, respectively). QMR measures of FM were highly and significantly correlated with chemical carcass analyses and DXA measures (r 2 ¼ 0.99 and r 2 ¼ 0.98, respectively). QMR and DXA FFM results were highly correlated (R 2 ¼ 0.99, Po0.01). TBW measures were strongly correlated between QMR and carcass analyses (R 2 ¼ 0.99, Po0.01). QMR overestimated FM by 2% and DXA measures (using the infant and adult scan programs) overestimated FM by 15% on average. Conclusion: QMR provides precise and accurate measures of FM, FFM and TBW in piglets weighing up to 50 kg. As the piglet is considered to be an excellent model of human development, these data suggest that QMR should provide the opportunity to acquire valuable body composition data in longitudinal studies in children, which is not possible or practical with other commercially available instrumentation.

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Section: Introductionmentioning

confidence: 99%

QMR: validation of an infant and children body composition instrument using piglets against chemical analysis

2010

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“…This study addresses its potential for infants, using piglets as a generally accepted research model for infant body composition (23,24).…”

Section: Introductionmentioning

confidence: 99%

Validation of Quantitative Magnetic Resonance Body Composition Analysis for Infants Using Piglet Model

Mitchell¹

2011

Pediatr Res

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ABSTRACT:A study was conducted to validate the use of a quantitative magnetic resonance (QMR) device for measuring the body composition of infants and neonates weighing Ͻ12 kg using the pig as a model. A total of 25 piglets weighing between 2 and 12 kg were studied. Body composition was assessed by QMR, dual-energy x-ray absorptiometry (DXA), and whole-body chemical analysis (CA) of carcass for lipid and water content. The precision, mean and SD of repeated measurements, of QMR to estimate fat mass (FM), lean mass (LM), and total body water (TBW) for five consecutive scans with reposition was 12.5, 32.0, and 36.0 g, respectively. QMR measures of FM, LM, and TBW were highly and significantly correlated with CA of carcass. In terms of accuracy, mean difference between QMR and CA (percent of mean value for CA), QMR overestimated FM by 40 g (4.7%), overestimated LM by 114.9 g (2.1%), and underestimated TBW by 134.6 g (3.1%). This study concludes that QMR provides precise and accurate measures of FM, LM, and TBW in piglet weighing up to 12 kg. These results suggest that QMR can provide valuable body composition data in longitudinal studies in infants. A ccurate assessment and tracking of infant body composition is useful in evaluating the amount and quality of weight gain, which can provide key information in both clinical and research settings. Body composition analysis (BCA) can be used to monitor and evaluate infant growth patterns, efficacy of nutritional and medical interventions, progression of chronic disease, and recovery from malnutrition (1-5).A large variety of nondestructive BCA methods have been developed, each with its advantages and shortcomings, such as air-displacement plethysmography (ADP) (6), bioelectrical impedance analysis (BIA) (7), dual-energy x-ray absorptiometry (DXA) (8), total-body electrical conductivity (TOBEC) (9), total body potassium (TBK) (10), isotope dilution (11), skin-fold thickness measurements (SFT) (12), multicompartment models (13), computed tomography (CT) (14), MRI (15), magnetic resonance spectroscopy (MRS) (16), and quantitative magnetic resonance (QMR) (17).Common shortcomings include complexity and time needed to obtain results (multicomponent models, TBK, isotope dilution, MRI, and MRS), immobilization requirement (MRI, MRS, CT, and DXA), expensive equipment (MRI, MRS, CT, DXA, QMR, and TOBEC), reliability and correspondence of relations between measured quantities and body components (BIA, TOBEC, ADP, and SFT), radiation exposure (CT and DXA), and potential vulnerability to oversimplification (ADP and SFT).QMR devices stand out in that they are fast and very easy to use, require no sedation or anesthesia, and are free of radiation, while capable of unsurpassed precision and high accuracy. Typical scan times range from Ͻ1 min to Ͻ4 min in different specific devices and applications, and less than half an hour of training is sufficient for a typical user.The QMR method is a branch of nuclear magnetic resonance (NMR), for whole body measurement of fat, lean tissues, free...

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“…Infant scan precision data in the literature are sparse, with most findings based on repeat scans of piglets. Precision values noted by other investigators include percentage CV for BMC of 2.0-2.8%, BMD of 1.5-2.5%, lean mass of 1.3-2.5%, with fat consistently showing the poorest repeatability with values approaching 6.9% (24)(25)(26)(27). These value ranges are not far removed from the percentage CV data from our infant phantom.…”

Section: Discussionmentioning

confidence: 62%

Solid anthropomorphic infant whole-body DXA phantom: design, evaluation, and multisite testing

Shypailo

Ellis

2013

Pediatr Res

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Background: Dual-energy X-ray absorptiometry (DXA) requires phantoms for quality control and cross-calibration. No commercially available phantoms are designed specifically for whole-body scanning of infants. Methods: We fabricated a phantom closely matching a 7-kg human infant in body habitus using polyvinyl chloride (PVC), nylon mix, and polyethylene for bone, lean tissue, and fat, respectively, for evaluating the comparability of instruments used in studies on infant body composition. We scanned the phantom multiple times for short-and long-term repeatability and then shipped it to six other sites for comparison scans. All instruments were Hologic Delphi or Discovery models. Scan analyses were in-house procedures (Hologic V12.1). results: Short-and long-term results were not significantly different. Nylon mix underrepresented expected lean mass values by 5%, PVC underrepresented bone by 12%, and polyethylene overrepresented fat by 30%. Precision values were as follows: lean mass ≈ 3%; bone ≈ 3.5%; and fat = 5.5-7.5%. Instruments differed significantly for bone mineral content and density results in most instances. Three instruments differed in fat and lean mass. The two Hologic models differed significantly in all compartments except bone density. conclusion: The phantom design came close to emulating bone, lean tissue, and fat and showed good reproducibility. Significant differences among various DXA instruments highlight the necessity of cross-calibration for any multicenter studies.

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Bone and Body Composition Measurements of Small Subjects: Discrepancies from Software for Fan-Beam Dual Energy X-Ray Absorptiometry

Abstract: The commercial software for fan-beam DXA measurement of piglets, matched for the size of human infants and young children, has major inaccuracies for bone mineral and body composition that become further exaggerated with increasing weight of the subject.

Cited by 30 publications

References 14 publications

QMR: validation of an infant and children body composition instrument using piglets against chemical analysis

QMR: validation of an infant and children body composition instrument using piglets against chemical analysis

Validation of Quantitative Magnetic Resonance Body Composition Analysis for Infants Using Piglet Model

Solid anthropomorphic infant whole-body DXA phantom: design, evaluation, and multisite testing

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