Inaccuracies Inherent in Patient-Specific Dual-Energy X-Ray Absorptiometry Bone Mineral Density Measurements: Comprehensive Phantom-Based Evaluation
- 1 February 2001
- journal article
- Published by Oxford University Press (OUP) in Journal of Bone and Mineral Research
- Vol. 16 (2), 417-426
- https://doi.org/10.1359/jbmr.2001.16.2.417
Abstract
An extensive series of dual-energy X-ray absorptiometry (DXA) scans and dual polyenergetic X-ray simulation studies of 150 different phantom arrays were carried out to evaluate quantitatively the extent of systematic inaccuracies inherent in DXA in vivo bone mineral density (BMD). These measurements are particularly relevant to lumbar vertebral and proximal femoral sites. The phantoms were specially fabricated near perfect absorptiometric representations of bone material, red marrow (RM) and yellow marrow (YM), and extraosseous mixtures of fat (F) and lean muscle that spanned the full range of soft tissue anthropometrics encountered clinically. In each case, the DXA-measured BMD values obtained using Hologic, Lunar, and Norland densitometers were found to be virtually the same and to be in excellent agreement with the corresponding quantitative simulation study BMD results. Comparisons of the known phantom BMD values and DXA-measured BMD in each case allowed the BMD inaccuracies to be evaluated. These present findings show that these ubiquitous inaccuracies in DXA BMD methodology are of in vivo soft tissue anthropometric genesis. It is found that patient-specific DXA-measured in vivo BMD inaccuracies as high as 20% or more can be readily anticipated clinically, particularly in cases of osteopenic, osteoporotic, and elderly patients. As these inaccuracies exceed considerably DXA precision errors, they may compromise patient-specific evaluations of fracture risk and, in prospective studies, mask or exaggerate clinically significant true changes in BMD. It is concluded that the magnitudes and variability of inherent inaccuracies in DXA-measured in vivo BMD underscore the need for prudence and circumspection in interpretations and assessments of DXA-based clinical studies.Keywords
This publication has 35 references indexed in Scilit:
- Analytic and quantitative exposition of patient‐specific systematic inaccuracies inherent in planar DXA‐derived in vivo BMD measurementsMedical Physics, 1998
- Pitfalls in the Measurement of Bone Mineral Density by Dual Energy X-ray AbsorptiometrySpine, 1996
- Precision and accuracy of measurements of whole-body bone mineral: comparisons between Hologic, Lunar and Norland dual-energy X-ray absorptiometersThe British Journal of Radiology, 1994
- Hip fractures in the elderly: A world-wide projectionOsteoporosis International, 1992
- Errors due to non-uniform distribution of fat in dual X-ray absorptiometry of the lumbar spineThe British Journal of Radiology, 1992
- The impact of measurement errors on the diagnostic value of bone mass measurements: Theoretical considerationsOsteoporosis International, 1991
- The error due to fat inhomogeneity in lumbar spine bone mineral measurementsClinical Physics and Physiological Measurement, 1989
- The effect of fat on bone mineral measurements in normal subjects with recommended values of bone, muscle and fat attenuation coefficientsClinical Physics and Physiological Measurement, 1987
- STATISTICAL METHODS FOR ASSESSING AGREEMENT BETWEEN TWO METHODS OF CLINICAL MEASUREMENTThe Lancet, 1986
- Epoxy resin based tissue substitutesThe British Journal of Radiology, 1977