The value of dual-energy x-ray absorptiometry (DEXA) in the estimation of body composition

Learning Objectives 1. To provide an overview of dual-energy x-ray absorptiometry (DEXA) and its applications. 2. To demonstrate specific situations that measurements of varying components of the body should be performed. 3. To compare techniques of body composition analysis in different/several groups of patients.

Lean body mass is a strong predictor of outcome in starvation and in a variety of acute and chronic illnesses. Depletion of fat-free mass (FFM) commonly occurs in patients with chronic obstructive pulmonary disease (COPD) and chronic renal failure (CRF). Several studies have proposed that FFM is a significant predictor factor of the respiratory function of obese patients with severe COPD, while depletion of lean body tissue/fat-free mass was a prominent finding in CRF. We have also studied, using DEXA, the relation of fat-free mass and bone mineral density with exercise performance in patients with COPD. Whole body DEXA (WBDEXA) can differentiate bone mineral content (BMC) and the soft tissue surrounding the bone by measuring the amount of fat and lean tissue. This exhibit will illustrate the application of WBDEXA in CRF and COPD patients, and its impact in the accurate body composition evaluation resulting in better care by improving their nutritional status. We will also discuss the superiority of WBDEXA compared with other techniques such as anthropometry and bioelectrical impedance analysis.