Learning objectives
Toexplain the basics of dual energy x-ray absorptiometry (DEXA) and its primary use in assessment of bone density.
To discuss the evolving role of DEXAin evaluation of soft tissues especially for body composition such as quantification of fatand estimation of skeletal muscle mass.
Background
Basics of DEXA:
Xraysare not sensitive in detecting bone loss in patients with osteoporosis. Reduction in bone density can be "seen" in radiographs only after 20-30% of bone mass is lost. DEXA is presently the gold standard and widely used technique for assessment of osteoporosis.
Principle:
DEXA principle is based on the fact that attenuation co-efficient of different tissues (such as bone or soft tissues) decrease at different rates with increase in energy. The difference in attenuation is higher with low energy X-ray beams(compared to...
Findings and procedure details
Body composition and applications:
Normal adults, metabolic syndrome and obesity:
Fat quantification and fat masss indices are better markers than body mass index (BMI). Lean mss index [appendicular lean mass=(arm+leg lean mass)/ht2]. Viseral fat can be separately quantified as well. (Fig. 7).
Obesity can be easily diagnosed even if BMI is normal (Fig.8).
Fraility and sarcopenia:
Definition (As per EWGSOP2) Sarcopenia was defined as 1. Low muscle strength by Hand grip strength and 2. Low muscle quantity and quality by Skeletal muscle index.
Cut-off value...
Conclusion
DEXA is a very useful and safe technology for evaluation of body composition. New interest has evolved in the applications of DEXA in quantification of fat in healthy and obese individuals, assessing lean mass in aged population (in suspected sarcopenia) and also helpful in studying body composition in athletes.
Personal information and conflict of interest
S. Srinivasan; Singapore/SG - nothing to disclose A. Kannivelu; Singapore/SG - nothing to disclose H. Chou; Singapore/SG - nothing to disclose
References
Different methods for diagnosis of sarcopenia and its association with nutritional status and survival in patients with advanced cancer in palliati... - PubMed—NCBI. (n.d.). Retrieved January 8, 2020, from https://www.ncbi.nlm.nih.gov/pubmed/30529186
Moon, J. J., Park, S.-G., Ryu, S. M., & Park, C.-H. (2018). New Skeletal Muscle Mass Index in Diagnosis of Sarcopenia. Journal of Bone Metabolism, 25(1), 15–21.
Onishi, S., Tajika, M., Tanaka, T., Hirayama, Y., Hara, K., Mizuno, N., Kuwahara, T., Okuno, N., Inaba, Y., Kodaira, T., Abe, T., Muro, K., Shimizu, M., & Niwa,...
