Effects of metal implants on whole-body dual-energy x-ray absorptiometry measurements of bone mineral content and body composition.
OBJECTIVE
The purpose of this study was to evaluate the influence of metal implants on measurements of bone mineral content and body composition by x-ray-based dual-photon absorptiometry.


METHODS
Four whole-body dual-photon absorptiometry scans were performed on 13 participants with metal rods either present or absent during the scans. The influence of the amount of metal (50 g, 100 g and 150 g), the proximity of the metal rod to the x-ray source and the reproducibility of any metal-induced effects were evaluated by altering the position or the size of the metal rod used, or both.


RESULTS
The presence of metal rods weighing 100 g or 150 g significantly increased reported total body mass and bone mineral content (p < 0.034). Soft-tissue mass was increased when the scan included the 100-g rod (p < 0.003). The proximity of the metal to the x-ray source did not have a significant influence on the body composition changes induced by the metal. The effects of the metal rods on body composition variables were reproducible.


CONCLUSIONS
The presence of metal rods inflated body composition variables measured by dual-photon absorptiometry; however, the effects are reproducible during repeat scans of an individual patient. Metal had the largest impact on whole-body bone mineral content, causing errors of 1.5%-3%.
Giangregorio
Lora M
LM
Department of Kinesiology, McMaster University.
Webber
Colin E
CE
D015502:Absorptiometry, Photon / Q000295:instrumentation; D000273:Adipose Tissue / Q000000981:diagnostic imaging; D000293:Adolescent; D000328:Adult; D001823:Body Composition / Q000502:physiology*; D001835:Body Weight / Q000502:physiology; D015519:Bone Density / Q000502:physiology*; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D012016:Reference Values; D015203:Reproducibility of Results