Dual-energy X-ray absorptiometry and body composition

Area of Science:

• Biomedical Engineering
• Human Physiology
• Medical Imaging

Background:

• Dual-energy X-ray absorptiometry (DXA) is a common method for assessing body composition, including fat, fat-free soft tissue, and bone mineral.
• Despite its widespread use, DXA technology has known limitations, particularly concerning inter-manufacturer and intra-manufacturer variability.
• Concerns regarding the validity and consistency of DXA measurements necessitate ongoing review and validation.

Purpose of the Study:

• To review recent literature on inter- and intra-manufacturer differences in DXA body composition measurements.
• To critically evaluate the validity of DXA measurements against established criterion methods.
• To highlight the implications of DXA limitations for researchers and clinical practice.

Main Methods:

• Systematic review of recent scientific literature.
• Analysis of studies comparing DXA machines from different manufacturers and generations.
• Evaluation of DXA validity against four-component models and other reference methods.

Main Results:

• Significant differences in body composition measurements exist between newer DXA machines and across manufacturers.
• These discrepancies can be unacceptable for multicenter studies and when upgrading equipment.
• DXA shows notable deviations from four-component models, with wide limits of agreement concerning for individual-level interpretation.

Conclusions:

• Investigators must recognize DXA technology's limitations when interpreting body composition data.
• Continued inter-machine comparisons and validation studies are crucial, especially with new software or hardware.
• DXA remains valuable for tracking compositional changes in longitudinal studies, but cross-calibration may be needed for cross-sectional research.