Single cross-sectional area of pectoralis muscle by computed tomography - correlation with bioelectrical impedance based skeletal muscle mass in healthy subjects.

PURPOSE: Skeletal muscle depletion is an important prognostic factor in patients with chronic obstructive pulmonary disease (COPD); a recent study demonstrated significant correlations between pectoralis muscle area on an axial CT image and COPD-related traits. The purpose of this study was to evaluate the relation between pectoralis muscle areas on CT scans and total body skeletal muscle mass (SMM) in healthy subjects.

METHODS: For 434 subjects that underwent a low-dose chest CT and bioelectrical impedance analysis (BIA) during health screening from January to June of 2014, cross-sectional area of pectoralis muscles were measured in CT scans. Pearson's correlation and multiple linear regression analysis were used to assess the relationship between cross-sectional CT areas of pectoralis muscles and BIA-assessed SMMs.

RESULTS: Mean age was 50 ± 10 years (78·8% were male). The mean cross-sectional area of pectoralis muscles was 24·1 cm2  ± 6·8. A moderate correlation was observed between pectoralis muscle area and BIA-based SMM (r = 0·665, P<0.001). Multivariable analysis showed CT determined pectoralis muscle area was significantly associated with BIA-assessed SMM after adjusting for gender, weight, height and age (β = 0·14 ± 0·02, P<0·001).

CONCLUSION: Cross-sectional area of the pectoralis muscles on single axial CT images shows moderate correlation with total body SMM determined by BIA in healthy subjects.