Regional skeletal muscle measurement: evaluation of new dual-energy X-ray absorptiometry model

• Published in: Journal of applied physiology (1985) Vol. 87; no. 3; pp. 1163 - 1171
• Main Authors: Wang, Wei, Wang, Zimian, Faith, Myles S, Kotler, Donald, Shih, Rick, Heymsfield, Steven B
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Am Physiological Soc 01.09.1999; American Physiological Society
• Subjects: Absorptiometry, Photon - methods; Adipose Tissue - anatomy & histology; Adipose Tissue - physiology; Adult; Algorithms; Biological and medical sciences; Body Composition - physiology; Bone Density; Forearm - physiology; Fundamental and applied biological sciences. Psychology; Humans; Leg - physiology; Male; Models, Biological; Muscle, Skeletal - chemistry; Organ Size - physiology; Predictive Value of Tests; Skin - anatomy & histology; Skin - chemistry; Skinfold Thickness; Striated muscle. Tendons; Tomography, X-Ray Computed; Vertebrates: osteoarticular system, musculoskeletal system; Human; Dual energy absorptiometry; Lean body mass; Corporal biometry; Models; Measurement method; Morphometry; Striated muscle; Body composition; X ray absorption
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/jappl.1999.87.3.1163

Obesity Research Center, St. Luke's-Roosevelt Hospital, Columbia University, College of Physicians and Surgeons, New York, New York 10025 Although there is growing interest in studying muscle distribution, regional skeletal muscle (SM) mass measurement methods remain limited. The aim of the present study was to develop a new dual-energy X-ray absorptiometry (DEXA) model for estimating regional adipose tissue-free skeletal muscle mass (AT-free SM). Relationships were derived from Reference Man data between tissue-system- level components (i.e., AT-free SM, AT, skeleton, and skin) and molecular-level components including fat-free soft tissue, fat, and bone mineral. The proposed DEXA-SM model was evaluated by multiscan computerized axial tomography (CT). Twenty-seven male subjects [age, 36 ± 12 (SD) yr; body mass, 73.2 ± 12.4 kg; 20   were healthy, and 7 had acquired immunodeficiency syndrome] completed DEXA and CT studies. Identical landmarks for DEXA and CT measurements were selected in three regions, including calves, thighs, and forearms. There was a strong correlation for AT-free SM estimates between the new DEXA and CT methods (e.g., sum of three regions, r  = 0.86,  P  < 0.001). Regional AT-free SM measured in the 27 subjects by DEXA and CT, respectively, were 3.44 ± 0.60 and 3.47 ± 0.55   kg (difference 0.9%, P  > 0.05) for calves, 10.49 ± 1.77 and 10.05   ± 1.79 kg (difference 4.4%, P  < 0.05) for thighs, 1.36 ± 0.49   and 1.20 ± 0.41 kg (difference 13.3%, P  < 0.01) for forearms, and 15.29 ± 2.33 and 14.72 ± 2.33 kg (difference 3.9%, P  < 0.05) for the sum all three regions. Although the suggested DEXA-SM model needs minor refinements, this is a promising in vivo approach for measurement of regional SM, because DEXA is widely available, relatively inexpensive, and radiation exposure is low. computerized axial tomography; body composition; adipose tissue; bone mineral content; connective tissue