Potential of whole-body dual-energy X-ray absorptiometry to predict muscle volume of psoas major, gluteus maximus and back muscles

Background: Measurement of trunk muscle volume using axial MR images is considered clinically meaningful for understanding several spinal pathologies such as low back pain and spinal sagittal imbalance. However, it remains unclear whether trunk muscle mass (TMM) measured by dual-energy X-ray absorptiometry (DXA) can predict trunk muscle volume. The aim of this study is to investigate correlation between TMM measured by DXA and cross-sectional area (CSA) of trunk muscles measured by MRI in healthy volunteers. Methods: A total of 48 healthy volunteers underwent whole-body DXA and MRI of spinopelvic region. CSAs of psoas major, back muscles, and gluteus maximus were measured on MR axial images. Correlations between TMM measured by DXA and CSA of each musculature were investigated. Spearman rank correlation coefficient was employed for statistical analysis. Results: There was a weak correlation between TMM and CSA of psoas major (r = 0.39, P = 0.0678) in men, and a moderate correlation was found in women (r = 0.58, P = 0.0021). There were moderate correlations between TMM and CSA of back muscles both in men (r = 0.63, P = 0.0012) and women (r = 0.63, P = 0.0007). There was a strong correlation between TMM and CSA of gluteus maximus in men (r = 0.72, P < 0.0001), and a moderate correlation was found in women (r = 0.69, P < 0.0001). Conclusions: TMM was significantly correlated with CSAs of back muscles and gluteus maximus. DXA-derived TMM could reflect the muscle volume of back muscles and gluteus maximus.