Psoas Muscle Cross-sectional Area as a Measure of Whole-body Lean Muscle Mass in Maintenance Hemodialysis Patients

J Ren Nutr. 2016 Jul;26(4):258-64. doi: 10.1053/j.jrn.2016.02.002. Epub 2016 Mar 16.


Objective: We investigate whether psoas or paraspinous muscle area measured on a single L4-L5 image is a useful measure of whole lean body mass (LBM) compared to dedicated midthigh magnetic resonance imaging (MRI).

Design: Observational study.

Setting: Outpatient dialysis units and a research clinic.

Subjects: One hundred five adult participants on maintenance hemodialysis. No control group was used.

Intervention: Psoas muscle area, paraspinous muscle area, and midthigh muscle area (MTMA) were measured by magnetic resonance imaging.

Main outcome measure: LBM was measured by dual-energy absorptiometry scan.

Results: In separate multivariable linear regression models, psoas, paraspinous, and MTMA were associated with increase in LBM. In separate multivariate logistic regression models, C statistics for diagnosis of sarcopenia (defined as <25th percentile of LBM) were 0.69 for paraspinous muscle area, 0.81 for psoas muscle area, and 0.89 for MTMA. With sarcopenia defined as <10th percentile of LBM, the corresponding C statistics were 0.71, 0.92, and 0.94.

Conclusions: We conclude that psoas muscle area provides a good measure of whole-body muscle mass, better than paraspinous muscle area but slightly inferior to midthigh measurement. Hence, in body composition studies a single axial MR image at the L4-L5 level can be used to provide information on both fat and muscle and may eliminate the need for time-consuming measurement of muscle area in the thigh.

Publication types

  • Observational Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Absorptiometry, Photon
  • Adult
  • Aged
  • Body Composition*
  • Body Mass Index
  • Cardiovascular Diseases / therapy
  • Diet
  • Dietary Proteins / administration & dosage
  • Female
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Nutrition Assessment
  • Prospective Studies
  • Psoas Muscles / anatomy & histology*
  • Renal Dialysis*
  • Renal Insufficiency, Chronic / therapy
  • Serum Albumin / metabolism


  • Dietary Proteins
  • Serum Albumin