Derivation of Whole Body Bone Measures Through Summation of Individual DXA Scans

Misic, Mark M.; Evans, Ellen M.

doi:10.1016/j.jocd.2005.10.002

« Previous Next »Journal of Clinical Densitometry
Volume 9, Issue 2 , Pages 184-190, April 2006

Derivation of Whole Body Bone Measures Through Summation of Individual DXA Scans

Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL

Received 12 August 2005; received in revised form 5 October 2005; accepted 5 October 2005.

Abstract

A major limitation of dual-energy X-ray absorptiometry (DXA) instruments is the size of the scanning region that precludes obtaining accurate data on individuals who are very wide and/or tall. The purpose of this study was to determine if whole body bone mineral values can be determined in individuals too wide and/or too tall for the scanning region using summed measures from multiple DXA scans. Two to four partial scans of the body were combined to predict bone mineral content (BMC) and bone mineral density (BMD) from a complete whole body (WB) scan. The results indicate that compared with the WB scan, there were strong relations and small differences when summing scans to simulate a wide or tall individual for BMC (wide: r = 0.999, mean [M] ± standard deviation_diff [SD]_diff = −2.1 ± 26.2 g, p = 0.62; tall: r = 0.999; M ± SD_diff = −5.9 ± 27.1 g, p = 0.17) or BMD (wide: r = 0.996; M ± SD_diff = 0.001 ± 0.011 g/cm², p = 0.54; tall: r = 0.994; M ± SD_diff = 0.004 ± 0.014 g/cm², p = 0.10). Notably the differences from the whole body scan were within measurement error. In conclusion, accurate assessment of bone mineral outcomes can be obtained on wide or tall individuals using summed values from multiple DXA scans.