Body composition by DXA

Abstract

Body composition measurements from DXA have been available since DXA technology was developed 30years ago, but are historically underutilized. Recently, there have been rapid developments in body composition assessment including the analysis and publication of representative data for the US, official usage guidance from the International Society for Clinical Densitometry, and development of regional body composition measures with clinical utility. DXA body composition is much more than whole body percent fat. In this paper celebrating 30years of DXA for body composition, we will review the principles of DXA soft tissue analysis, practical clinical and research applications, and what to look for in the future.

Keywords: Bariatrics; Current and future use; Sarcopenia; Total body DXA in athletes.

Copyright © 2017 Elsevier Inc. All rights reserved.

Figures

Figure 1

(left) Screenshot from a Lunar DPX pencil beam system circa 1990. (from (5)). (right) Screenshot from Hologic Horizon circa 2016 (courtesy of J. Shepherd).

Figure 2

Comparisons of table scan areas of three current DXA systems (LEFT). Comparison of table weight limits across makes and models (RIGHT).

Figure 3

Examples of UCSF algorithms to separate DXA images into bone, fat, and lean tissues (left). These images are used to construct statistical appearance models (SAM) that compactly describe tissue variance across individuals (middle). We have used SAMs to identify tissue shape and distribution phenotypes that are associated with adverse metabolic outcomes (right).